JPH09200532A - Multi-value image data transmission device - Google Patents

Abstract

(57) Abstract: The present invention provides a multi-valued image data transmission device capable of compression-encoding multi-valued image data at a high compression rate and transmitting the multi-valued image data, and receiving and appropriately decoding and outputting the multi-valued image data. A multi-valued image data transmission device 1 expands multi-valued image data input from an input unit 2 into bit planes BP7 to BP0 from MSB to LSB, and stores the corresponding storage area 3a in a bit plane memory 3. Store in ~ 3h. The upper 3 bit planes BP7 to BP5 of the bit plane memory 3 are sequentially transferred to the gray coding unit 4 for each bit plane BP7 to BP5, gray coded, and then the upper bit plane BP7 in the coding unit 5. To bit planes BP5 are sequentially compression-encoded, transmitted from the transmission unit 7 to the other party, and the lower 5 bit bit planes BP4 to BP0 are transferred to the binarization unit 6 and binarized. The coding unit 5 sequentially performs compression coding, and the transmission unit 7 transmits the data to the other party.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-valued image data transmission apparatus, and more particularly, to a multi-valued image data compression-encoded multi-valued image data at a high compression ratio, and a multi-valued image data which is received and appropriately decoded and output. The present invention relates to an image data transmission device.

[0002]

2. Description of the Related Art Conventionally, in an image data transmission apparatus, for example, a facsimile apparatus, as shown in the block diagram of FIG. 12, a facsimile apparatus 70 is controlled by a system control unit 71, and a scanner 72 is used for transmission. The image data of the read original is read by the encoding / decoding unit 73 by M
H (Modified Huffman) coding method, MR (Modufied R)
elliptic element address designate) encoding method, or compression encoding using a standard encoding method for binary facsimile such as MMR (Modified MR) encoding method, and then temporarily storing it in the image memory 74 to establish a communication control unit. The data is output to the line L via the communication unit 75, the modem 76 and the network control unit 77 to be transmitted to the partner facsimile machine. When receiving, the facsimile device 70 receives the encoded image data sent via the line L by the network control unit 77, the modem 76, and the communication control unit 75 under the control of the system control unit 71. After being temporarily stored in the image memory 74, the encoding / decoding unit 73 decodes the original image data and the plotter 78 records and outputs the original image data. In FIG. 12, the operation display section 79 is provided with various operation keys for performing various operations such as transmission operation and a display for displaying information from the facsimile device 70 to the operator. It is connected.

In the conventional facsimile apparatus 70, only binary image data, that is, black and white binary image data is handled, but recently, due to the development of the recording system, one pixel has a plurality of gradations. You can record with,
Accordingly, it is necessary to transmit multi-valued image data even in the image data transmission method.

However, since the data amount of multi-valued image data is extremely large as compared with that of binary image data, if the data is encoded and transmitted by the conventional encoding method, the communication time becomes longer, and the communication becomes longer. The cost will be high.

Therefore, it is necessary to efficiently compress and code multi-valued image data for transmission. As a compression coding method of such multi-valued image data, for example, ADCT (Adaptive Discrete Cosine) has been conventionally used. Transform) is used to transform an image, and then entropy coding is performed, or the image is decomposed into bit planes and each plane is compressed by a normal binary coding method.

An example of using the latter method is a bit plane coding method and apparatus described in Japanese Patent Laid-Open No. 5-300382. This method uses arithmetic coding as a binary coding method, is configured as a matrix of a plurality of pixel values, and is the same in the method of decomposing a digital image in which each pixel value is represented as a k-bit binary number. Forming a first bit plane consisting of each bit of importance,
Forming k-1 or less bit planes of a plurality of bits having a specific bit importance different from the bit importance of the first bit plane, and at least one of the bit planes. Encoding each bit of the k-1 or less bit planes according to the context formed by each bit value from the two bit planes. That is, this method incorporates other bit-plane information and extends the context pixel assignment to include pixels from both the current and previous planes, thereby providing digital in progressive mode without gray code representation. It is intended to efficiently store, transmit and / or display images. The term "progressive mode" used in Japanese Unexamined Patent Publication No. 5-300382 is based on the meaning of IS.
O / IEC Commission Draft 11544-Coded Display of Picture and Audio Information-Progressive Binary Image Compression, WG9
-SIR It seems to be a translation of the progressive mode defined by JBIG (Joint Binary Image Group) on September 11, 1991, but the defined progressive mode is a transmission in which the image changes from low resolution to high resolution. While the mode is shown, the above publication uses it as a transmission mode in which an image changes from a binary image to a multi-valued image.

[0007]

However, in the encoding method and the encoding apparatus described in Japanese Patent Laid-Open No. 5-300382, the image data is decomposed into bit planes, and each plane is compressed and encoded. At the time of encoding, since the bit plane encoding is performed by referring to the plane in which the pixel of interest exists and the other plane pixels, there is a problem that the compression rate does not become as high as intended.

That is, in contrast to the reduction of the entropy of each plane when the Gray code is used, even if the reference pixel is expanded to a plane other than the plane in which the pixel of interest exists, the entropy is rarely reduced. In order to increase the height, it is necessary to refer to more bit planes at the same time, which causes a new problem of increasing the size of the device.

In order to transmit a high-quality image, it is usually necessary to transmit an image of, for example, about 8 bits / pixel, but if this is encoded by the bit plane encoding method, one image is transmitted. 8 bit planes are required to configure the above, and communication time is long. As a method of reducing this bit plane, for example, there is a method of using a multi-level dither method which has an effect of reducing the amount of data while suppressing deterioration of image quality. When simply applied, the information on each bit plane becomes discrete, the compression rate decreases, and the communication time cannot be shortened as intended.

In the bit plane coding system, the MSB (Most Significant Bit) side or the LSB is used.
The planes are sequentially encoded from the (Least Significant Bit) side, but when the lower bits are binarized by the dither method or the error diffusion method, the standard encoding method for the ordinary facsimile (for example, the MH method, the MR method) is used. , MMR method),
There is a problem in that not only the data cannot be compressed, but also the data amount may become larger than the original data due to the encoding.

Further, in the bit plane coding method, the arithmetic coding method (QM-Coder) is used for the coding.
Can be used, and in the case of performing arithmetic coding, the compression rate can be improved by performing the information source separation using the pixel reference template. However, the template normally used by default is not necessarily suitable for the systematic dither image and the like, and if the default template is used as it is, the compression rate cannot be improved.
Therefore, conventionally, there is an adaptive template in which the template shape is adaptively changed according to the state of the image, and when this is used, the compression rate can be improved from several times to more than ten times in the case of the systematic dither method. However, the algorithm for changing the shape of the adaptive template is not simple, and the circuit scale of the encoder increases, and the steps according to the algorithm are required until the template conforms to the features of the dither matrix. In the meantime, there is a problem that the compression rate is lower than in the case of using the template after adaptation.

Therefore, in the invention according to claim 1, in the bit plane encoding, the multi-valued image data is divided into the upper bit side and the lower bit side, and the upper bit side is
The multi-level dither method is used by gray-coding the data of each pixel in the gradation direction, compression-coding each bit plane, and binarizing and compressing the lower-bit side after compression. It is an object of the present invention to provide a multi-valued image data transmission device which can improve the compression efficiency without increasing the number of pixel change points of each bit plane.

According to a second aspect of the present invention, in the bit plane encoding, the data of each pixel is gray-coded in the gradation direction on the upper bit side, and then each bit plane is subjected to a normal binary facsimile standard code. It is compression-encoded by the encoding method, and the lower bit side is binarized and then not compressed, thereby preventing an increase in the code amount by compressing the binary facsimile standard encoding method. It is an object of the present invention to provide a multi-valued image data transmission device capable of improving compression efficiency.

According to a third aspect of the present invention, whether the operator compresses and transmits the lower bit side depending on whether the multi-valued image data has many continuous tone images such as photographs or many images such as characters, By making it possible to select whether to transmit the data without compression, it is possible to appropriately prevent an increase in the code amount by compressing with the standard encoding method for binary facsimile, and to further improve the compression efficiency. An object is to provide a multi-valued image data transmission device.

According to the fourth aspect of the present invention, whether the multi-valued image data is automatically discriminated whether there are many continuous tone images such as photographs or images such as characters, and the lower bit side is compression-coded and transmitted. , It is possible to automatically select whether to send it without compression,
An object of the present invention is to provide a multi-valued image data transmission device capable of more appropriately preventing an increase in the code amount by compressing with the standard encoding method for binary facsimiles and further improving the compression efficiency. I am trying.

According to a fifth aspect of the present invention, in the bit plane coding, the upper bit side is gray coded, and then each bit plane is compression-coded by the arithmetic coding method using a default template to obtain the lower bit. On the side, compression encoding is performed by an arithmetic encoding method using a template corresponding to the dither matrix, thereby simplifying the encoding means on the transmitting side and the decoding means on the receiving side, while improving the compression efficiency. It is an object of the present invention to provide a multivalued image data transmission device that can be used.

According to a sixth aspect of the present invention, it is divided into a high-order bit side and a low-order bit side, the high-order bit side is gray-coded for each pixel, then compression-coded for each bit plane, and the low-order bit side is binarized. It is an object of the present invention to provide a multi-valued image data transmission device that can appropriately decode and reconstruct multi-valued image data that has been compression-encoded and transmitted.

According to a seventh aspect of the present invention, the high-order bit side and the low-order bit side are divided, and the high-order bit side is gray-coded for each pixel, then compression-coded for each bit plane, and the low-order bit side is binarized. It is an object of the present invention to provide a multi-valued image data transmission device that can appropriately decode and reconstruct multi-valued image data that has been transmitted after being compressed.

The present invention is divided into an upper bit side and a lower bit side, the upper bit side is gray-coded for each pixel, compression-coded for each bit plane, and the lower bit side is binarized. It is an object of the present invention to provide a multi-valued image data transmission device that can appropriately decode and reconstruct multi-valued image data that has been transmitted after being uncompressed or compression-encoded.

According to a ninth aspect of the present invention, the high-order bit side and the low-order bit side are divided, and the high-order bit side is gray-coded for each pixel, and then the first pixel reference template which is the default for each bit plane is used. Compression-encoded using, and the lower bit side is binarized by the systematic dither method,
To provide a multi-valued image data transmission apparatus capable of appropriately decoding and reconstructing multi-valued image data that has been compression-encoded and transmitted using a second pixel reference template corresponding to a dither matrix. It is an object.

[0021]

According to a first aspect of the present invention, there is provided a multivalued image data transmission device, wherein multivalued image data input from an input means is encoded by a Gray code encoding method and transmitted by a transmission means. In the multi-valued image data transmission device, a storage unit that expands the input multi-valued image data into bit planes and stores each bit plane,
Gray-coding means that gray-codes each pixel data of the multi-valued image data expanded on the bit plane in the storage means in the gradation direction; and the multi-valued image data expanded on the bit plane in the storage means. A binarizing unit for binarizing and an encoding unit for compressing and encoding the multi-valued image data are provided, and the multi-valued image data expanded on the bit plane in the storage unit is located at a predetermined bit position at the upper bit side. And the lower bit side, the upper bit side is Gray coded for each pixel by the Gray coding unit, and then the coding unit compression-codes each bit plane and transmits the lower bit side. The above object is achieved by performing binarization by the binarization unit, compression-encoding by the encoding unit and transmitting.

Here, the storage means has, for example, a storage area for the number of gradations of the multi-valued image data, and stores the multi-valued image data expanded into bit planes for each bit plane.

The gray coding means gray-codes each pixel data of the multi-valued image data of the upper several bits stored in the storage means by bit plane expansion and gray-codes it in the gradation direction, and outputs it to the coding means. To do. The binarizing means converts the remaining low-order few bits of multi-valued image data stored in the storage means by bit plane expansion into two by a predetermined binarizing method.
It is digitized and output to the encoding means.

The encoding means compression-encodes the bit planes inputted from the gray encoding means and the binarizing means by a predetermined encoding method, outputs the compression data to the transmission means, and the transmission means transmits it to the other party.

According to the above construction, the multi-valued image data is divided into the high-order bit side and the low-order bit side at a predetermined bit position, the high-order bit side is gray-coded, compression-coded and transmitted, and the low-order bit side is sent. Since it can be binary-coded, compression-encoded, and then transmitted, the gray code can be used to reduce the change points of pixels to improve the compression efficiency and to use the multi-level dither method. In addition, it is possible to improve the compression efficiency of each bit plane while reducing the number of planes to be transmitted, and it is possible to shorten the communication time.

A multivalued image data transmission apparatus according to a second aspect of the present invention is a multivalued image data transmission apparatus for encoding multivalued image data input from an input means by a Gray code encoding method and transmitting it by a transmission means. A storage unit that expands the input multi-valued image data into bit planes and stores each bit plane; and pixel data of the multi-valued image data expanded into the bit planes in the storage unit in the gradation direction. Gray coding means for gray coding, binarizing means for binarizing the multi-valued image data expanded on the bit plane in the storage means, and multi-valued image data compressed by a binary facsimile standard encoding method. And encoding means for encoding, wherein the multi-valued image data expanded in a bit plane in the storage means is arranged at a predetermined bit position at a higher bit side and a lower bit side. And the upper bit side is gray coded for each pixel by the gray coding means, and then the coding means compressively codes each bit plane for transmission and the lower bit side is the The above object is achieved by transmitting the data in a non-compressed state after binarizing it by the digitizing means.

According to the above configuration, the multi-valued image data is divided into the high-order bit side and the low-order bit side at a predetermined bit position, the high-order bit side is gray-coded, compression-coded and transmitted, and the low-order bit side is transmitted. Since it can be transmitted without being compressed after being binarized, by using the Gray code, it is possible to reduce the change points of pixels and improve the compression efficiency, and at the same time, the standard encoding method for binary facsimile is used. It is possible to prevent an increase in the code amount by compressing the data in step (1), reduce the number of planes to be transmitted, improve the compression efficiency of each bit plane, and shorten the communication time.

According to a third aspect of the present invention, there is provided a multivalued image data transmission device, wherein multivalued image data input from the input means is encoded by the Gray code encoding system and transmitted by the transmission means. A storage unit that expands the input multi-valued image data into bit planes and stores each bit plane, and a pixel unit of each pixel data of the multi-valued image data expanded into the bit planes in the storage unit is grayed in the gradation direction. Gray coding means for coding,
A binarizing means for binarizing the multi-valued image data expanded into bit planes in the storage means; an encoding means for compression-encoding the multi-valued image data by a binary facsimile standard encoding method; When the value image data includes many continuous tone images such as photographs, the first mode is selected, and when there are many images such as characters, the second mode is selected. The multi-valued image data expanded on the bit plane is divided into a high-order bit side and a low-order bit side at a predetermined bit position, the high-order bit side is gray coded for each pixel by the gray coding means, and then the coding means The bit planes are compression-encoded and transmitted by the bit planes, and the lower bit side is binarized by the binarization means when the selection mode selects the first mode. After that, the data is transmitted in an uncompressed state, and when the selection unit selects the second mode, the binarization unit performs binarization, and the encoding unit compresses and encodes the data for transmission. Thus, the above-mentioned object is achieved.

Here, the coding means performs compression coding by the standard coding system for binary facsimile such as the MH coding system, the MR coding system, or the MMR coding system.
The selection unit uses, for example, a predetermined key of the operation unit of the multi-valued image data transmission device, and when the operator has many continuous tone images such as photographs in the multi-valued image data to be transmitted, the first key When the mode is selected and there are many images such as characters, the second mode is selected.

According to the above configuration, the multi-valued image data is divided into the high-order bit side and the low-order bit side at a predetermined bit position, the high-order bit side is gray-coded, compression-coded and transmitted, and the low-order bit side is transmitted. Depending on whether the multi-valued image data has many continuous tone images such as photographs or many images such as characters, it is binarized and then uncompressed according to the operator's selection, or a standard code for binary facsimiles. Since it can be compression-encoded by the encoding method and transmitted, by using the Gray code, it is possible to reduce the change points of pixels and improve the compression efficiency, and to compress with the standard encoding method for binary facsimile. Therefore, when the code amount increases, it is possible to improve the compression efficiency of each bit plane by transmitting without encoding and reducing the number of planes to be transmitted. It can be, it is possible to shorten the communication time.

According to a fourth aspect of the present invention, there is provided a multi-valued image data transmission device in which multi-valued image data input from the input means is encoded by the Gray code encoding system and transmitted by the transmission means. A storage unit that expands the input multi-valued image data into bit planes and stores each bit plane; and pixel data of the multi-valued image data expanded into the bit planes in the storage unit in the gradation direction. Gray coding means for gray coding, binarization means for binarizing the multi-valued image data expanded on the bit plane in the storage means, and compression coding of the image data by a binary facsimile standard coding method. And the encoding means for determining whether there are many continuous tone images such as photographs or images such as characters in the multivalued image data, and determines that there are many continuous tone images. And an image area separation unit that selects the second mode when the first mode is selected and it is determined that there are many images such as characters, and the multi-valued image expanded into a bit plane in the storage unit. The data is divided into a high-order bit side and a low-order bit side at a predetermined bit position, the high-order bit side is gray-coded for each pixel by the Gray coding means, and then compression-coded for each bit plane by the coding means. When the image area separation means selects the first mode while transmitting the lower bit side, the image area separation means performs binarization by the binarization means, and then transmits the image data in an uncompressed state. When the means selects the second mode, the above-described object is achieved by performing binarization by the binarization means, compression-encoding by the encoding means, and transmitting.

According to the above construction, it is automatically determined whether the multi-valued image data has many continuous tone images such as photographs or many images such as characters, and the lower bit side is compression-encoded for transmission.
It is possible to automatically select whether or not to transmit the data without compression, and it is possible to more appropriately prevent the amount of code from increasing by compressing with the standard encoding method for binary facsimile, and further improve the compression efficiency. You can

According to a fifth aspect of the present invention, there is provided a multi-valued image data transmission device, wherein multi-valued image data input from the input means is encoded by the Gray code encoding method and transmitted by the transmission means. In the storage unit, the input multi-valued image data is expanded into bit planes and stored for each bit plane, and each pixel data of the multi-valued image data expanded into the bit planes in the storage unit is displayed in the gradation direction. Gray coding means for gray coding, binarizing means for binarizing the multi-valued image data expanded in bit planes in the storage means by a systematic dither method using a predetermined dither matrix, and a default Of the first pixel reference template and a second pixel reference template corresponding to the dither matrix,
Coding means for compressing and coding multi-valued image data by an arithmetic coding method using the first pixel reference template or the second pixel reference template,
After dividing the multi-valued image data expanded on the bit plane in the storage means into a high-order bit side and a low-order bit side at a predetermined bit position, the high-order bit side is gray coded for each pixel by the gray coding means. , The encoding means arithmetically encodes each bit plane using the first pixel reference template, transmits the lower bit side by the binarizing means, and then the encoding is performed. The above-mentioned object is achieved by arithmetically encoding and transmitting by the means using the second pixel reference template.

Here, the binarizing means binarizes the multivalued image data by the systematic dither method using a predetermined dither matrix, and the encoding means uses the default first image reference template, or The multi-valued image data is encoded by the arithmetic encoding method using the second pixel reference template corresponding to the dither matrix.

According to the above configuration, the multi-valued image data is divided into the high-order bit side and the low-order bit side at a predetermined bit position, the high-order bit side is gray coded, and then the default template is used to perform the arithmetic coding method. After compression-encoding and transmitting, and binarizing the lower bit side, it is possible to compression-encode and transmit by the arithmetic encoding method using a template according to the dither matrix, so by using the Gray code, It is possible to reduce the change points of pixels and improve the compression efficiency, and also to improve the compression efficiency and shorten the communication time while simplifying the encoding means on the transmission side and the decoding means on the reception side. it can.

According to a sixth aspect of the present invention, there is provided a multivalued image data transmitting apparatus, wherein the multivalued image data encoded by the Gray code encoding method received by the receiving means is decoded and output by the output means. In the data transmission device, a decoding means for decoding the received encoded multi-valued image data, a binary evolution means for converting the gray code data decoded by the decoding means into natural binary data, and a bit. Storage means for storing plane-expanded multi-valued image data, divided into an upper bit side and a lower bit side, and the upper bit side is gray-coded for each pixel and then compression-coded for each bit plane. When the compression-encoded multi-valued image data is transmitted after the lower bit side is binarized, the upper bit side is sequentially decoded by the decoding means. After being reproduced as the output plane data, each pixel data is converted into natural binary data by the binarizing means and stored in the corresponding bit plane position of the storing means, and the lower bit side is converted by the decoding means. After decoding, by storing as bit plane data in the corresponding bit plane position of the storage means, reconstructing an image, and outputting the multivalued image data stored in the storage means by the output means, It has achieved the above objectives.

Here, the decoding means decodes the multi-valued image data compressed and encoded by the decoding method corresponding to the encoding method of the encoding means on the transmission side, and the binarizing means is the decoding means. When the decoded multi-valued image data is gray code data, this gray code data is converted into natural binary data.

According to the above configuration, the upper bit side and the lower bit side are divided, the upper bit side is gray-coded for each pixel, then the compression coding is performed for each bit plane, and the lower bit side is binarized. After that, the multi-valued image data that has been compression-encoded and transmitted can be appropriately decoded and reconstructed.

According to a seventh aspect of the present invention, there is provided a multivalued image data transmitting apparatus, wherein the multivalued image data encoded by the Gray code encoding method received by the receiving means is decoded and output by the output means. In the data transmission device, a decoding means for decoding the received encoded multi-valued image data, a binary evolution means for converting the gray code data decoded by the decoding means into natural binary data, and a bit. Storage means for storing plane-expanded multi-valued image data, divided into an upper bit side and a lower bit side, and the upper bit side is gray-coded for each pixel and then compression-coded for each bit plane. When the uncompressed multi-valued image data is transmitted after the lower bit side is binarized, the upper bit side is sequentially decoded by the decoding means and bit-coded. After playing as Ndeta,
Each pixel data is converted into natural binary data by the binarization means and stored in the corresponding bit plane position of the storage means, and the lower bit side is directly used as bit plane data in the corresponding bit plane position of the storage means. The object is achieved by storing the image, reconstructing the image, and outputting the multivalued image data stored in the storage means by the output means.

According to the above construction, the upper bit side and the lower bit side are divided, the upper bit side is gray-coded for each pixel, then compression-coded for each bit plane, and the lower bit side is binarized. After that, the multi-valued image data transmitted without compression can be appropriately decoded and reconstructed.

In the multi-valued image data transmission apparatus of the present invention as defined in claim 8, the multi-valued image data encoded by the Gray code encoding method received by the receiving means is decoded and output by the output means. In the data transmission device, a decoding means for decoding the received encoded multi-valued image data, a binary evolution means for converting the gray code data decoded by the decoding means into natural binary data, and a bit. Storage means for storing multi-valued image data expanded into a plane and whether the multi-valued image data received by the receiving means is compressed data or non-compressed data, and the decoding means and the storage means And a discriminating and switching means for outputting by switching between the upper bit side and the lower bit side, the upper bit side is gray-coded for each pixel, and When the non-compressed or compression-encoded multi-valued image data is transmitted after the low-order bit side is binarized after compression-encoded for each unit, the high-order bit side is sequentially processed by the decoding means. After decoding and reproducing as bit plane data, each pixel data is converted into natural binary data by the binarization means and stored in the corresponding bit plane position of the storage means. When the means outputs the received multi-valued image data to the decoding means, after decoding by the decoding means, it is stored in the corresponding bit plane position of the storage means as bit plane data, and the discrimination switching means When the received multi-valued image data is output to the storage means as it is, the corresponding bit plane position of the storage means becomes bit plane data. So stored, the image to reconstruct the, by outputting multi-valued image data stored in said memory means by said output means, to achieve the above objects.

Here, the discrimination switching means discriminates whether the received multi-valued image data is compressed data or non-compressed data, and receives it according to whether it is compressed data or non-compressed data. The multi-valued image data is output by switching between the decoding means and the storage means.

According to the above configuration, the upper bit side and the lower bit side are divided, the upper bit side is gray-coded for each pixel, compression-coded for each bit plane, and the lower bit side is binarized. After that, the multi-valued image data that has been transmitted after being uncompressed or compression-encoded can be appropriately decoded and reconstructed according to whether it is compression-encoded or uncompressed.

According to a ninth aspect of the present invention, there is provided a multivalued image data transmission device, wherein the multivalued image data encoded by the Gray code encoding method received by the receiving means is decoded and output by the output means. The data transmission device includes a default first pixel reference template and a second pixel reference template corresponding to a dither matrix, and the received image data is stored in the first pixel reference template or the second pixel. Decoding means for decoding by the arithmetic decoding method using the reference template,
The binarizing means for converting the gray code data decoded by the decoding means into natural binary data, and the storing means for storing the multi-valued image data expanded in bit planes are provided, and the upper bit side and the lower bit side are provided. , The upper bit side is gray-coded for each pixel, and then compression-coded using the first pixel reference template which is the default for each bit plane, and the lower bit side is binary by the systematic dither method. After being converted, when multi-valued image data compressed and encoded using the second pixel reference template corresponding to the dither matrix is transmitted, the higher-order bit side is sequentially processed by the decoding means. After decoding using the first pixel reference template and reproducing as bit plane data, each pixel data is converted into natural binary data by the binarizing means. In other words, the data is stored in the corresponding bit plane position of the storage means, the lower bit side is decoded by the decoding means using the second pixel reference template, and then stored as the lower bit plane data. Store it in the corresponding bitplane position of the instrument,
The above object is achieved by reconstructing an image and outputting the multi-valued image data stored in the storage means by the output means.

Here, the decoding means decodes the received image data by the arithmetic decoding method using the default first pixel reference template or the second pixel reference template corresponding to the dither matrix.

According to the above configuration, the upper bit side and the lower bit side are divided, and the upper bit side is gray-coded for each pixel, and then the first pixel reference template which is the default for each bit plane is used. Compression encoded,
After the lower bit side is binarized by the systematic dither method, the multi-valued image data that has been compression-encoded and transmitted using the second pixel reference template according to the dither matrix is appropriately decoded and re-encoded. Can be configured.

[0047]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The embodiments described below are preferred embodiments of the present invention, and therefore have various technically preferable limitations. However, the scope of the present invention refers to the present invention particularly in the following description. Unless otherwise stated, the present invention is not limited to these embodiments.

FIGS. 1 and 2 are views showing a multi-valued image data transmission device to which the first embodiment of the multi-valued image data transmission device of the present invention is applied. In this embodiment, a bit plane code is used. In the conversion, the multi-valued image data is divided into the high-order bit side and the low-order bit side, and on the high-order bit side, the data of each pixel is gray-coded in the gradation direction, and then compression-coded for each bit plane. The lower bit side is binarized and then compression-encoded.
It corresponds to.

In FIG. 1, a multi-valued image data transmission device 1
Includes an input unit 2, a bit plane memory 3, a Gray coding unit 4, a coding unit 5, a binarization unit 6, a transmission unit 7, and the like. Although not shown, a control unit, an operation unit, and the like are additionally provided. I have it. Note that the multi-valued image data will be described below assuming that it is 8 bits / pixel.

The input unit (input means) 2 is, for example, a scanner device or a video camera device, and is used to generate multivalued image data and input it into the multivalued image data transmission device 1.

The multi-valued image data input from the input unit 2 is expanded into bit planes BP7 to BP0 from MSB to LSB by a control unit (not shown), and the bit planes BP7 to BP0 are stored in the bit plane memory 3. To be done. The bit plane memory (storage means) 3 has at least a number of storage areas corresponding to the number of gradations of multi-valued image data. As shown, the storage areas 3a to 3h for eight binary images are provided to store the expanded bit planes BP7 to BP0, respectively.

As shown in FIG. 2, in the case of multi-valued image data of 8 bits / pixel, the bit planes BP7 to BP0 are a collection of binary equal bits representing one pixel for each plane. The image is decomposed into eight binary images.

The bit plane memory 3 is a bit plane BP of the storage areas 3a to 3c for storing the upper 3 bits.
7 to BP5 are output to the Gray coding unit 4, and the Gray coding unit (Gray coding unit) 4 inputs the bit planes BP7 to BP5 from the bit plane memory 3.
Is gray-coded (alternating binary coding) in the gradation direction (depth direction) for each plane and output to the coding unit 5.

The bit plane memory 3 has the lower 5 bits.
The bit planes BP4 to BP0 of the storage areas 3d to 3h that store bits are output to the binarization unit 6 and the binarization unit 6 is output.
Outputs the sequentially input pixel data to a coding unit 5 by binarizing the pixel data by a predetermined binarizing method, for example, a binarizing method such as an error diffusion method.

The encoding unit (encoding means) 5 performs compression encoding in order from the upper bit plane BP0 to the lower bit plane BP7 and outputs it to the transmitting unit 7. As the encoding method in the encoding unit 5, for example, various standard methods such as a normal facsimile standard encoding method such as an MH encoding method, an MR encoding method, an MMR encoding method, or an arithmetic encoding method are used. Can be used.

The transmission unit (transmission means) 7 transmits (transmits) the compression-encoded multi-valued image data input from the encoding unit 5 to a predetermined destination by wire or wirelessly.

The transmission order of the transmission unit 7 does not have to be the order of the bit planes BP7 to BP0, as long as it is consistent with the reception side. Further, in the multi-valued image data transmission device 1, 3 bits are used for the upper bit side and 5 bits are used for the lower bit side. However, when the bit planes BP7 to BP0 are divided into the upper side and the lower side, the above 3 bits are used. It is not limited to dividing into 5 bits and
For example, the method may be such that the upper bits are 4 bits and the lower bits are 4 bits, or another method may be used.

Next, the operation will be described. When the 8-bit / pixel multi-valued image data is input from the input unit 2, the multi-valued image data transmission device 1 outputs the multi-valued image data from the MSB to the LSB to the bit plane BP7 under the control of a control unit (not shown). To BP0 and store in corresponding storage areas 3a to 3h of the bit plane memory 3, respectively.

The multi-valued image data transmission apparatus 1 uses the bit planes BP7 to BP5 of the storage areas 3a to 3c, which store the upper 3 bits of the bit plane memory 3, respectively.
The bit planes BP7 to BP5 are sequentially transferred to the Gray coding unit 4 and are gray coded by the Gray coding unit 4. Then, the coding unit 5 sequentially compression-codes the upper bit planes BP7 to BP5, Transmission unit 7
To send to the other party.

Then, the multi-valued image data transmission apparatus 1 has the bit planes BP4 to BP of the storage areas 3d to 3h which store the lower 5 bits of the bit plane memory 3, respectively.
The P0 is sequentially transferred to the binarization unit 6, binarized by the binarization unit 6, sequentially encoded by the encoding unit 5, and transmitted from the transmission unit 7 to the other party.

Therefore, according to the multi-valued image data transmission device 1, in the bit plane encoding, the multi-valued image data is divided into the high-order bit side and the low-order bit side, and the data of each pixel on the high-order bit side. Is gray-coded in the gradation direction and then compression-coded for each bit plane BP7 to BP0. The lower bit side can be binarized and then compression-coded for transmission. , And each bit plane BP7-B
The change point of the pixel of P0 can be reduced and the compression efficiency can be improved.

In the above embodiment, the binary data is binarized by the dither method of mixing the original data with noise and then binarized, or the arithmetic coding method (QM-Coder).
Can be compression encoded. Then, when performing the binarization using the dither method, the binarization is performed using the dither matrix. As the dither matrix,
For 5 bits, for example, there is one as shown in FIG. 3. In the systematic dither method using this dither matrix, there is a pixel having a correlation at every 8 pixels.

When arithmetic coding is used as the coding method, for example, a binary image data compression standard JBIG 3-line template (pixel reference template) as shown in FIG. By performing the separation, the compression ratio can be improved. In FIG. 4, the mark x indicates the pixel of interest, and the inside of the frame is the reference pixel.

However, the template normally used by default is not
It may not be suitable, and it may not be possible to obtain the intended high compression rate. For example, in the case of the dither matrix shown in FIG. 3 above, pixels having a high correlation occur in a cycle of 8 pixels, and therefore the template shown in FIG. The compression ratio is reduced due to the decrease of the medium ratio.

Therefore, the compression rate can be improved by using a template as shown in FIG. 5 according to the bit position of the multi-valued image data. That is, FIG.
If the middle x mark is the pixel of interest and α is the reference pixel, α
The reference pixel at the position of is moved so as to refer to the position 8 pixels before the target pixel on the same line as the target pixel, so that the pixel at the position having a higher correlation with the target pixel is referred to as the reference pixel. Can be encoded by
The compression ratio can be improved.

However, in this case, there is an adaptive template in which the template shape is adaptively changed according to the state of the image. However, when this adaptive template is used, the compression rate is several times to several times in the case of the systematic dither method. Although it is improved by about 10 times, the algorithm that adaptively changes the template shape is not simple, and the circuit scale of the encoder becomes extremely large, and the template is adapted to the characteristics of the dither matrix according to the algorithm. The steps are required, and until the matching, the compression rate is lower than that in the case of using the template after the matching.

Therefore, in the above embodiment, the lower 5
Regarding bit planes BP4 to BP0 on the bit side, FIG.
When binarization is performed using the dither matrix as shown in the above, the bit plane B on the upper 3 bits side of the multi-valued image data which is gray coded by the gray coding unit 4
P7 to BP5 are compressed and encoded by using the default template as shown in FIG. 4, and the lower 5 bits are compressed and encoded by using the template as shown in FIG. The compression efficiency can be improved without increasing the circuit scale. This method corresponds to claim 5.

That is, in the encoding unit 5 of FIG. 1, the default template (first pixel reference template) as shown in FIG. 4 and the template (second pixel) as shown in FIG. (The pixel reference template of No. 1) and the bit planes BP7 to BP5 on the higher-order bit side input from the Gray encoding unit 4 are compression-encoded using the default first pixel reference template. The bit planes BP4 to BP0 on the lower bit side input from the binarization unit 6 are compression-encoded using the second pixel reference template according to the dither matrix. In this case, J
In the BIG encoding method, since the moving destination of the floating pixel (pixel corresponding to α shown in FIG. 5) of the adaptive template can be indicated in the code string, the corresponding position of this floating pixel (for example, The data indicating the position (8 pixels apart on the same line as the pixel of interest) is described in the code.

Therefore, since it is not necessary to use the adaptive template, the compression efficiency can be improved without increasing the circuit scale.

In this case, since the pixels having a high correlation differ depending on the dither matrix used, it is necessary to use a template corresponding thereto.

FIG. 6 is a diagram showing a multi-valued image data transmission device to which the second embodiment of the multi-valued image data transmission device of the present invention is applied. In this embodiment, in the bit plane encoding, The multi-valued image data is divided into the upper bit side and the lower bit side, and on the upper bit side, after the data of each pixel is gray coded in the gradation direction, compression coding is performed for each bit plane, and the lower bit 2 for the bit side
After being digitized, it is transmitted in an uncompressed form, which corresponds to claim 2.

The present embodiment is applied to a multi-valued image data transmission device similar to that of the first embodiment, and has the same configuration as the multi-valued image data transmission device shown in FIG. The same reference numerals are given to the parts, and detailed description thereof will be omitted.

In FIG. 6, a multi-valued image data transmission device 1
0 includes an input unit 2, a bit plane memory 3, a Gray encoding unit 4, an encoding unit 5, a binarizing unit 6, a transmitting unit 7, and the like, like the multi-valued image data transmission device 1. Although not shown, a control unit, an operation unit and the like are additionally provided.
Also in the case of the present embodiment, the multi-valued image data will be described below assuming that it is 8 bits / pixel.

In the multi-valued image data transmission device 10, only the gray coded image data of the gray coding unit 4 is output to the coding unit 5, and the binarized image data of the binarization unit 6 is directly transmitted. It is output to the unit 7.

Multivalued image data transmission device 1 of the present embodiment
0 indicates that when the multi-valued image data transmission device 1 receives the multi-valued image data of 8 bits / pixel from the input unit 2 in the same manner as described above, the multi-valued image data M
The bit planes BP7 to BP0 from SB to LSB are expanded and stored in the corresponding storage areas 3a to 3h of the bit plane memory 3, respectively.
The bit planes BP7 to BP5 of the storage areas 3a to 3c storing the upper 3 bits of
The data is transferred to the Gray coding unit 4 every P7 to BP5. The gray coding unit 4 receives the input bit planes BP7-
After BP5 is Gray coded, it is output to the coding unit 5,
The encoding unit 5 sequentially compresses and encodes the upper bit plane BP7 to the bit plane BP5, and transmits from the transmitting unit 7 to the other party.

Then, the multi-valued image data transmission device 10 is
Bit planes BP4 to BP4 of storage areas 3d to 3h respectively storing the lower 5 bits of the bit plane memory 3
BP0 is sequentially transferred to the binarization unit 6, and the binarization unit 6 outputs 2
When the value is converted, the value is directly transmitted from the transmitter 7 to the other party.

Therefore, the multi-valued image data transmission device 10
According to this, in the bit plane encoding, the multi-valued image data is divided into the upper bit side and the lower bit side, and the upper bit side is gray-coded in the gradation direction of the data of each pixel, It is possible to perform compression encoding for each of the planes BP7 to BP5, binarize the lower bit side, and transmit the data as it is in an uncompressed state.

As a result, the lower bit is encoded by using the multi-value dither method or the error diffusion method, so that the compression rate is lowered and a code which exceeds the original data amount is generated. In addition, it is possible to prevent the compression from being impossible with the binary facsimile standard encoding method, and after the binarization, the control system is easily transmitted by directly transmitting without encoding. Can improve the compression efficiency,
The transmission time can be shortened.

FIG. 7 is a diagram showing a multi-valued image data transmission device to which the third embodiment of the multi-valued image data transmission device of the present invention is applied. In this embodiment, in the bit plane encoding, The multi-valued image data is divided into the upper bit side and the lower bit side, and on the upper bit side, after the data of each pixel is gray coded in the gradation direction, compression coding is performed for each bit plane, and the lower bit As for the bit side, depending on whether the multi-valued image data has many continuous tone images such as photographs or many images such as characters, it is either compression-encoded according to the operator's selection, or transmitted uncompressed. This corresponds to claim 3.

The present embodiment is applied to a multi-valued image data transmission device similar to that of the second embodiment, and has the same configuration as the multi-valued image data transmission device shown in FIG. The same reference numerals are given to the parts, and detailed description thereof will be omitted. Also in the case of the present embodiment, the multi-valued image data will be described below assuming that it is 8 bits / pixel.

In FIG. 7, the multi-valued image data transmission device 2
0 indicates the input unit 2, the bit plane memory 3, the gray coding unit 4, the coding unit 5, the binarization unit 6, the transmission unit 7, the switching unit 21, and the like, as in the multi-valued image data transmission device 1. Although not shown, it also includes a control unit, an operation unit, and the like.

The operation section has a mode selection key (mode selection means) for selecting a mode depending on whether multi-valued image data input from the input section 2 has many continuous tone images such as photographs or many images such as characters. ) Is provided and the operator
Using this mode selection key, when there are many continuous tone images such as photographs, the photograph mode is selected as the first mode, and when there are many letters and the like, the character mode is selected as the second mode.

In the multi-valued image data transmission device 10, only the gray coded image data of the gray coding unit 4 is output to the coding unit 5, and the binarized image data of the binarization unit 6 is switched to the switching unit. 21 is output.

The switching section 21 switches the binarization section 6 to the coding section 5 and the transmission section 7 and connects them, and the switching terminal 21a is connected to the coding section 5 by the control section (not shown).
And a terminal b connected to the transmitter 7 are alternatively connected.

When the first mode (photograph mode) is selected by the mode selection key of the operation unit, the control unit (not shown)
When the switching terminal 21a of the switching unit 21 is connected to the terminal a side and the second mode (character mode) is selected, the switching terminal 2
1a is connected to the terminal b side.

Multi-valued image data transmission device 2 of the present embodiment
According to 0, the multi-valued image data transmission device 1 receives multi-valued image data of 8 bits / pixel from the input unit 2 under the control of the control unit (not shown) in the same manner as described above. From MSB to LSB bit plane BP7-
It is expanded to BP0 and stored in the corresponding storage areas 3a to 3h of the bit plane memory 3, respectively.

Then, the operator judges whether the input multi-valued image data has many continuous tone images such as photographs or many characters, and when there are many continuous tone images, the operator selects the mode selection key of the operation unit. , The photo mode is selected as the first mode, and when there are many characters and the like, the character mode is selected as the second mode.

The multi-valued image data transmission device 20 includes a gray coding unit for the bit planes BP7 to BP5 of the storage areas 3a to 3c in which the upper 3 bits of the bit plane memory 3 are stored, sequentially for each bit plane BP7 to BP5. 4 and the input bit planes BP7 to BP5 are Gray-coded by the Gray coding unit 4 and output to the coding unit 5, and the coding unit 5 outputs the upper bit plane B.
P7 to bit plane BP5 are sequentially compression-encoded and transmitted from the transmission unit 7 to the other party.

Then, the multi-valued image data transmission device 20 is
Bit planes BP4 to BP4 of storage areas 3d to 3h respectively storing the lower 5 bits of the bit plane memory 3
BP0 is sequentially transferred to the binarization unit 6, and the binarization unit 6 outputs 2
When binarized and output to the switching unit 6, the multi-valued image data has many continuous tone images such as photographs and the first mode is selected, the binarizing unit 6 is transmitted from the switching unit 21 to the transmitting unit 7. Bit planes BP7 to B that are connected and binarized by the binarization unit 6
The P0 is transmitted from the transmitting unit 7 to the other party as it is uncompressed.
In the multi-valued image data transmission device 20, when there are many images such as characters in the multi-valued image data and the second mode is selected, the switching unit 21 connects the binarization unit 6 to the encoding unit 5, Bit planes BP4 to BP binarized by the binarization unit 6
The P0 is compression-encoded by the encoder 5 and then transmitted via the transmitter 7.

Therefore, the multi-valued image data transmission device 10
According to this, in the bit plane encoding, the multi-valued image data is divided into the upper bit side and the lower bit side, and the upper bit side is gray-coded in the gradation direction of the data of each pixel, Compression coding is performed for each of the planes BP7 to BP5, and for the lower bit side, depending on the mode selected by the operator depending on whether the input multi-valued image data has many images such as characters or many continuous tone images such as photographs. ,
It is possible to select whether to perform compression coding and transmission after binarization, or to perform transmission after being binarized and then in uncompressed state as it is.

As a result, with respect to the lower bits, when images such as characters are large, they are binarized, compression encoded and transmitted, and when there are many continuous tone images such as photographs, they are binarized and then uncompressed. The transmission efficiency can be improved and the transmission time can be shortened.

FIG. 8 is a diagram showing a multi-valued image data transmission device to which the fourth embodiment of the multi-valued image data transmission device of the present invention is applied. In this embodiment, in the bit plane encoding, The multi-valued image data is divided into the upper bit side and the lower bit side, and on the upper bit side, after the data of each pixel is gray coded in the gradation direction, compression coding is performed for each bit plane, and the lower bit Regarding the bit side, the multi-valued image data is automatically discriminated whether there are many continuous tone images such as photographs or many images such as characters, and compression-encoded or non-compressed data is transmitted. It corresponds to 4.

The present embodiment is applied to a multi-valued image data transmission device similar to that of the third embodiment, and has the same configuration as the multi-valued image data transmission device shown in FIG. The same reference numerals are given to the parts, and detailed description thereof will be omitted. Also in the case of the present embodiment, the multi-valued image data will be described below assuming that it is 8 bits / pixel.

In FIG. 8, the multi-valued image data transmission device 2
0 is the input unit 2, the bit plane memory 3, the Gray coding unit 4, the coding unit 5, the binarization unit 6, the transmission unit 7, the switching unit 21 and the image, as in the multi-valued image data transmission device 1. Although not shown, it is provided with a control unit, an operation unit, etc.

In the multi-valued image data transmission device 10, only the gray coded image data of the gray coding unit 4 is output to the coding unit 5, and the binarized image data of the binarization unit 6 is switched to the switching unit. 21 is output.

The switching unit 21 connects the binarizing unit 6 by switching between the encoding unit 5 and the transmitting unit 7, and the switching terminal 21a of the encoding unit is switched by the control signal input from the image area separating unit 31. 5 connected to the terminal a and the transmitter 7 connected to the terminal b
And are alternatively connected.

The image area separating section (image area separating means) 31 includes bit plane memories 3 to BP7-B.
P0 is input, and the image area separation unit 31 determines whether the multivalued image data is an image with many continuous tone images such as a photograph or a character image based on each bit plane input from the bit plane memory 3. It is determined whether there are many images, and when there are many continuous tone images, a control signal for selecting the first mode and connecting the switching terminal 21a to the terminal b side is selected. Select mode and switch terminal 2
A control signal for connecting 1a to the terminal a side is output to the switching unit 21.

Multi-valued image data transmission device 3 of the present embodiment
According to 0, the multi-valued image data transmission device 1 receives multi-valued image data of 8 bits / pixel from the input unit 2 under the control of the control unit (not shown) in the same manner as described above. From MSB to LSB bit plane BP7-
It is expanded to BP0 and stored in the corresponding storage areas 3a to 3h of the bit plane memory 3, respectively.

Then, the image area separation unit 31 determines whether the input multi-valued image data has many continuous tone images such as photographs or many characters, and when there are many continuous tone images, the first image A control signal for selecting the mode and connecting the switching terminal 21a to the terminal b side is provided to the switching unit 21 when a large number of characters and the like are selected and a second mode is selected for connecting the switching terminal 21a to the terminal a side. Output.

The multi-valued image data transmission device 30 gray-codes the bit planes BP7 to BP5 of the storage areas 3a to 3c in which the upper 3 bits of the bit plane memory 3 are stored, sequentially for each bit plane BP7 to BP5. 4 and the input bit planes BP7 to BP5 are Gray-coded by the Gray coding unit 4 and output to the coding unit 5, and the coding unit 5 outputs the upper bit plane B.
P7 to bit plane BP5 are sequentially compression-encoded and transmitted from the transmission unit 7 to the other party.

Then, the multi-valued image data transmission device 30 is
Bit planes BP4 to BP4 of storage areas 3d to 3h respectively storing the lower 5 bits of the bit plane memory 3
BP0 is sequentially transferred to the binarization unit 6, and the binarization unit 6 outputs 2
When the first region is selected by the image area separation unit 31, the conversion unit 21 binarizes the image after binarizing and outputting the binarized image to the switching unit 6. 6
Is connected to the transmission unit 7, and the bit planes BP7 to BP0 binarized by the binarization unit 6 are transmitted from the transmission unit 7 to the other party without being compressed. In the multi-valued image data transmission device 30, when there are many images such as characters in multi-valued image data and the second mode is selected by the image area separation unit 31, the switching unit 21 causes the binarization unit 6 to encode. 5, the bit planes BP4 to BP0 binarized by the binarizing unit 6 are connected by the encoding unit 5,
After compression and encoding, the data is transmitted via the transmission unit 7.

Therefore, the multi-valued image data transmission device 10
According to this, in the bit plane encoding, the multi-valued image data is divided into the upper bit side and the lower bit side, and the upper bit side is gray-coded in the gradation direction of the data of each pixel, Compression coding is performed for each of the planes BP7 to BP0, and on the lower bit side, the image area separation unit 31 automatically determines whether the input multi-valued image data has many images such as characters or many continuous tone images such as photographs. Then, it is possible to select whether the data is binarized and then compression-encoded for transmission, or binarized and then transmitted as it is for transmission.

As a result, with respect to the lower bits, when there are many images such as characters, they are automatically binarized and then compressed and encoded for transmission. When there are many continuous tone images such as photographs, they are automatically binarized. After conversion, it can be transmitted uncompressed, and the compression time can be improved appropriately and efficiently according to the image of the multi-valued image data without the operator having to make a selection operation. It can be shortened.

FIG. 9 is a diagram showing a multi-valued image data transmission device to which a sixth embodiment of the multi-valued image data transmission device of the present invention is applied. This embodiment is the same as the first embodiment. Which receives the data transmitted from the multivalued image data transmission device 1 in the form, appropriately decodes the data, and then outputs the data.
This corresponds to claim 6.

In FIG. 9, the multi-valued image data transmission device 4
0 includes a receiving unit 41, a decoding unit 42, a bit plane memory 43, an output unit 44, and the like, and although not shown,
In addition, a control unit, an operation unit, etc. are provided.

The reception section (reception means) 41 operates under the control of a control section (not shown) and receives data transmitted from the transmission section 7 of the multi-valued image data transmission apparatus 1 by wire or wirelessly, Output to the decoding unit 42.

The decoding unit (decoding means) 42 operates under the control of a control unit (not shown) and has the same decoding table or template as the encoding unit 5 of the multivalued image data transmission apparatus 1. Alternatively, the coded data input from the receiving unit 41 is constructed and decoded, and the decoded upper 3 bit side bit planes BP7 to BP5 are provided to the natural binary evolution unit 43, and the lower 5 bit side bit planes BP4 to BP are included.
0 is directly output to the bit plane memory 44 and stored in the bit plane memory 44.

The natural binary evolution unit (binary evolution means) 43 is a gray-coded upper 3-bit bit plane BP7.
.About.BP5 are converted into natural binary data for each bit plane BP7 to BP5, output to the bit plane memory 44, and stored in the bit plane memory 44.

Bit plane memory (storage means) 44
Has a storage area of a number corresponding to the number of gradations of multi-valued image data. For example, in order to store image data of 8 gradations, as shown in FIG. Bit planes BP7-B provided with storage areas 44a-44h
Store P0 respectively.

The bit plane memory 44 stores the bit planes BP7 to BP5 corresponding to the upper 3 bits of the multivalued image data input from the natural binary evolution unit 43 in the storage area 44a.
To 44c, the bit planes BP4 to BP0, which are the lower 5 bits input from the decoding unit 42, are stored in the storage area 44.
Stored in d to 44h, respectively. That is, the data are stored in the respective storage areas 44a to 44h of the bit plane memory 44 in the order transmitted from the multi-valued image data transmission device 1 of FIG.

The multi-valued image data transmission device 40 receives all the bit planes BP7 to BP0, performs the above decoding and natural binarization or decoding, and outputs the bit plane memory 4
When stored in 4, the control unit (not shown) reads the bit planes BP7 to BP0 of the bit plane memory 44, reconstructs the image, and then outputs the image to the output unit 45.

An output unit (output means) 45, which is composed of, for example, a printer device, a display device, a hard disk, or the like, is capable of performing hard copy of multi-valued image data on the printer device, soft copying (displaying) on the display device, or , Output to a hard disk, etc.

Next, the operation will be described. The multi-valued image data transmission device 40 is the multi-valued image data transmission device 1 shown in FIG.
The multi-valued image data is reconstructed and output after receiving and decoding the data from the multi-valued image data transmission device 1.
After P7 to BP5 are Gray coded, they are compression-encoded, and the bit planes BP4 to BP0 on the lower 5 bits are binarized, then compression-encoded and transmitted.

Therefore, the multi-valued image data transmission device 40 is
When this data is received by the receiving unit 41, first, all the data is decoded by the decoding unit 42 in accordance with the coding of the multi-valued image data transmission device 1, and the upper 3 bit side bit planes BP7 to BP5 are Is Nature 2 Evolution 4
After converting the gray coded data in 3 into natural binary data, the storage area 44a of the bit plane memory 44
~ 44c. In addition, the multi-valued image data transmission device 4
0 is the bit planes BP4 to BP0 on the lower 5 bit side
With respect to, the bit planes BP4 to BP0 decoded by the decoding unit 42 are directly transferred to the storage areas 44d to 44h of the bit plane memory 44 and stored therein.

The multi-valued image data transmission device 40 receives all the data, decodes it, then naturally binarizes it, or stores it as the bit planes BP7 to BP0 in the bit plane memory 44 as it is. After reading the bit planes BP7 to BP0 from the plane memory 44 and reconstructing them as multi-valued image data, the output unit 4
5, and the output unit 45 outputs a hard copy, a soft copy, or a copy.

As described above, according to the multi-valued image data transmission device 40 of the present embodiment, the multi-valued image data is divided into the upper bit side and the lower bit side, and the upper bit side bit planes BP7 to BP5. Is Gray-coded, then compression-coded, and bit planes BP4 to B on the lower bit side
When P0 is binarized, compression-encoded, and then transmitted, it can be appropriately decoded, reconstructed, and output.

In this case, as described above, when the received data is coded by arithmetic coding, for the bit planes BP7 to BP5 on the high-order bit side,
Decoding is performed using the default first pixel reference template shown in FIG. 4, and for the bit planes BP4 to BP0 on the lower bit side, the second pixel reference template corresponding to the dither matrix shown in FIG. Decrypt using. This corresponds to claim 9.

That is, the decoding unit 42 is provided with a default first pixel reference template and a second pixel reference template corresponding to the dither matrix, and the receiving unit 41 sets the bit plane BP7 on the upper 3 bits side. ~
When BP5 is input, bit planes BP7 to BP5
Are decoded using the default first pixel reference template shown in FIG. 4, and output to the natural binary evolution unit 43. Further, the decoding unit 42, when receiving the bit planes BP4 to BP0 on the lower 5 bit side from the receiving unit 41,
The bit planes BP4 to BP0 are decoded using the second pixel reference template according to the dither matrix shown in FIG. 5, and output to the bit plane memory 44.

In this case, as described above, floating pixels of the adaptive template (corresponding to α in FIG. 5) in the coded sequence.
Since the data indicating the moving destination is added, it is not necessary to separately indicate the moving destination information by a protocol or the like, and the decoding unit 42 selects the reference pixel based on the data in the encoded sequence, Decryption can be done.

Therefore, the transmitting side uses the arithmetic coding method,
Even if the upper side is encoded with the default first image reference template and the lower side is encoded with the second image reference template according to the dither matrix and transmitted, simple and small decoding The unit 42 can appropriately decode, reconstruct, and output.

FIG. 10 is a diagram showing a multi-valued image data transmission device to which the seventh embodiment of the multi-valued image data transmission device of the present invention is applied. This embodiment is the same as the second embodiment. The data transmitted from the multi-valued image data transmission device 10 in the form is received, appropriately decoded, and then output, which corresponds to claim 7.

The present embodiment is applied to the same multivalued image data transmission device as the sixth embodiment, and has the same configuration as the multivalued image data transmission device shown in FIG. The same reference numerals are given to the parts, and detailed description thereof will be omitted.

In FIG. 10, the multi-valued image data transmission device 50, like the multi-valued image data transmission device 40, is provided with a receiving unit 41, a decoding unit 42, a bit plane memory 43, an output unit 44, etc. However, only the upper 3 bits of data are input to the decoding unit 42.

That is, the receiving unit 41 receives the data transmitted by wire or wirelessly from the transmitting unit 7 of the multi-valued image data transmitting apparatus 1, and decodes the bit planes BP7 to BP5 on the upper 3 bits side thereof. And outputs to the unit 42 and the bit planes BP4 to
The BP0 is output to the bit plane memory 44 as it is.

The decoding unit 42 decodes and decodes the encoded data input from the receiving unit 41 based on the same decoding table or template as the encoding unit 5 of the multivalued image data transmission device 1. The bit planes BP7 to BP5 on the higher 3 bits are output to the natural binarization unit 43. Natural 2 evolution part 43 is the top 3 gray coded
The bit planes BP7 to BP5 of the bits are converted into natural binary data for each bit plane BP7 to BP5, output to the bit plane memory 44, and stored in the bit plane memory 44.

The bit plane memory 44 stores the bit planes BP7 to BP5 corresponding to the upper 3 bits of the multivalued image data input from the natural binary evolution unit 43 in the storage area 44a.
To 44c, the bit planes BP4 to BP0, which are the lower 5 bits input from the decoding unit 42, are stored in the storage area 44.
Stored in d to 44h, respectively.

The multi-valued image data transmission device 50 receives all the bit planes BP7 to BP0, and performs the above decoding and natural binarization or the bit plane memory 44 as it is.
, The bit planes BP7 to BP0 of the bit plane memory 44 are read out, the image is reconstructed, and then output to the output unit 45. At the output unit 45, the multivalued image data is hard-copied by the printer device, It is soft-copied (displayed) on a display device or recorded and output to a hard disk or the like.

That is, the multi-valued image data transmission device 50
Receives the data from the multi-valued image data transmission device 10 shown in FIG. 6, decodes the upper 3 bits and expands the lower 5 bits to the bit plane memory 44 as it is. The data is reconstructed and output. From the multi-valued image data transmission device 10, the upper 3 bit side bit planes BP7 to BP5 are gray coded, then compression encoded, and the lower 5 bit side bits are output. After the planes BP4 to BP0 are binarized, they are transmitted uncompressed.

Therefore, the multi-valued image data transmission device 50 is
When this data is received by the reception unit 41, first, the decoding unit 42 decodes the bit planes BP7 to BP5 on the higher 3 bits side in accordance with the encoding of the multi-valued image data transmission device 10, and then the natural 2 The evolution unit 43 converts the gray-coded data into natural binary data and transfers it to the storage areas 44a to 44c of the bit plane memory 44.
In addition, the multi-valued image data transmission device 50 is configured so that the bit planes BP4 to BP0 on the lower 5 bit side of the multi-valued image data transmission device 50 receive the signal from the receiving unit 4.
Since it is transmitted uncompressed from 1, it is directly transferred to the storage areas 44d to 44h of the bit plane memory 44 and stored therein.

The multi-valued image data transmission device 50 receives all the data, decodes it, and then naturally binarizes it or stores it in the bit plane memory 44 as bit planes BP7 to BP0 as it is. , The bit planes BP7 to BP0 are read from the bit plane memory 44, reconstructed as multi-valued image data, transferred to the output unit 45, and the output unit 45 outputs hard copy, soft copy, or copy. Let

As described above, according to the multi-valued image data transmission device 50 of the present embodiment, the multi-valued image data is divided into the high-order bit side and the low-order bit side, and the high-order bit side bit planes BP7 to BP5. Is Gray-coded, then compression-coded, and bit planes BP4 to B on the lower bit side
When P0 is transmitted after being binarized without being compressed, it can be appropriately decoded, reconstructed, and output.

FIG. 11 is a diagram showing a multi-valued image data transmission device to which the eighth embodiment of the multi-valued image data transmission device of the present invention is applied. This embodiment is the same as the third embodiment. 9. The data transmitted from the multivalued image data transmission device 20 of the embodiment or the multivalued image data transmission device 30 of the fourth embodiment is received, appropriately decoded, and then output. It corresponds to.

The present embodiment is applied to a multi-valued image data transmission device similar to that of the sixth embodiment, and has the same configuration as the multi-valued image data transmission device shown in FIG. The same reference numerals are given to the parts, and detailed description thereof will be omitted.

In FIG. 11, the multi-valued image data transmission device 60, like the multi-valued image data transmission device 40, includes a receiving unit 41, a decoding unit 42, a bit plane memory 43, an output unit 44, and the like, and switches between them. The unit 61 is provided, and in addition, a control unit, an operation unit, and the like (not shown) are provided.

That is, the receiving section 41 has the multi-valued image data transmission device 20 or the multi-valued image data transmission device 30.
Of the data transmitted by wire or wirelessly from the transmission unit 7 and outputs the upper 3 bit side bit planes BP7 to BP5 to the decoding unit 42, and the lower 5 bit side bit planes BP4 to BP0. , To the switching unit 61.

The switching unit (discrimination switching means) 61 includes a receiving unit 4
1 is switched to the decoding 42 and the bit plane memory 44 and connected, and the switching terminal 61 is switched by the control unit (not shown).
a is selectively connected to the terminal a connected to the decoding unit 42 and the terminal b connected to the bit plane memory 44.

If the received data is encoded data, the control unit (not shown) switches the switching terminal 61 of the switching unit 61.
a is connected to the terminal a side, and when the data is not encoded, the switching terminal 61a is connected to the terminal b side.

The decoding unit 42 receives the upper 3 data input from the receiving unit 41 based on the same decoding table or template as the encoding unit 5 of the multivalued image data transmission device 1.
The bit planes BP7 to BP5 on the bit side are decoded, and the decoded bit plane BP7 on the upper 3 bits side is decoded.
~ BP5 is output to the natural binary evolution section 43, and the switching section 6
Bit planes BP4 to BP0 from 1 to lower 5 bits
Is input, the bit planes BP4 to BP0 are decoded and output to the bit plane memory 44. Nature 2
The evolution unit 43 converts the gray-coded upper 3 bit bit planes BP7 to BP5 into the bit planes BP7 to BP7.
It is converted into natural binary data for each BP5, output to the bit plane memory 44, and stored in the bit plane memory 44.

The bit plane memory 44 stores the bit planes BP7 to BP5, which are the upper 3 bits of the multivalued image data input from the natural binary evolution unit 43, in the storage area 44a.
To 44c from the switching unit 61 or the decoding unit 42
Bit plane B which is the lower 5 bits input from
P4 to BP0 are stored in the storage areas 44d to 44h, respectively.

The multi-valued image data transmission device 60 receives all the bit planes BP7 to BP0 and stores them in the bit plane memory 44 by performing the above decoding and natural binarization, the decoding or the bit plane memory 44. After reading BP7 to BP0 and reconstructing an image, the image is output to the output unit 45. At the output unit 45, multivalued image data is hard-copied by a printer device or soft-copied (displayed) on a display device. Alternatively, it is recorded and output to a hard disk or the like.

That is, the multi-valued image data transmission device 60
Receives the data from the multi-valued image data transmission device 20 shown in FIG. 7 or the multi-valued image data transmission device 30 shown in FIG. 8 and decodes the upper 3 bits side and the lower 5 bits side as it is or After decoding and expanding in the bit plane memory 44, the multi-valued image data is reconstructed and output, and the upper 3 bits from the multi-valued image data transmission device 20 or the multi-valued image data transmission device 30. Side bit planes BP7 to BP5 are Gray coded and then compressed and coded, and lower 5 bit side bit planes BP4 to BP0 are binarized and then compressed or coded and transmitted. .

Therefore, the multi-valued image data transmission device 60 is
When this data is received by the reception unit 41, first, the decoding unit 42 decodes the bit planes BP7 to BP5 on the higher 3 bits side in accordance with the encoding of the multi-valued image data transmission device 10, and then the natural 2 The evolution unit 43 converts the gray-coded data into natural binary data and transfers it to the storage areas 44a to 44c of the bit plane memory 44.
Further, the multi-valued image data transmission device 40 determines whether the bit planes BP4 to BP0 on the lower 5 bit side are compression-encoded or uncompressed, and when they are compressed, the switching unit 61 decodes them. After being transferred to the digitization unit 42 and decoded, the storage area 44 of the bit plane memory 44
d to 44h, and when uncompressed, the storage area 4 of the bit plane memory 44 is directly passed through the switching unit 61.
4d to 44h are transferred and stored.

The control unit confirms, on the protocol, whether the received data is compressed data or uncompressed data, or a message indicating that the received data is added to a part of the code. Make a decision based on the information in. For example, on the G3 facsimile protocol, when notifying from the transmitting side to the receiving side, information to that effect can be added by an NSF (non-standard function notification) signal.

The multi-valued image data transmission device 60 receives all the data, decodes it, and then naturally binarizes it, or selects a state in which it remains decoded or received, and the bit plane memory 44 Bit planes BP7 to BP
If it is stored as 0, the bit planes BP7 to BP0 are read from the bit plane memory 44, reconstructed as multi-valued image data, and then transferred to the output unit 45, and the output unit 45 performs hard copy, soft copy, or
Causes output such as copying.

As described above, according to the multi-valued image data transmission apparatus 60 of the present embodiment, the multi-valued image data is divided into the upper bit side and the lower bit side, and the upper bit side bit planes BP7 to BP5. Is Gray-coded, then compression-coded, and bit planes BP4 to B on the lower bit side
After P0 is binarized, it can be appropriately decoded, reconstructed, and output when it is transmitted in a compressed or non-compressed state according to the state of the image.

Although the invention made by the present inventor has been specifically described based on the preferred embodiments, the present invention is not limited to the above, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

[0147]

According to the multivalued image data transmission apparatus of the invention described in claim 1, the multivalued image data is divided into the upper bit side and the lower bit side at a predetermined bit position, and the upper bit side is gray coded. After that, the data can be compression-encoded and transmitted, and the lower bit side can be binarized and then compression-encoded and transmitted. Therefore, by using the Gray code, the change points of pixels are reduced and the compression efficiency is improved. In addition, the number of planes to be transmitted can be reduced, the compression efficiency of each bit plane can be improved, and the communication time can be shortened without using the multilevel dither method.

According to the multi-valued image data transmission device of the second aspect of the invention, the multi-valued image data is divided into a high-order bit side and a low-order bit side at a predetermined bit position, and the high-order bit side is gray-coded. It is possible to compress and code the data, to binarize the lower bit side, and then to send the data uncompressed. Therefore, by using the Gray code, it is possible to reduce the change points of pixels and improve the compression efficiency. In addition, it is possible to prevent an increase in the code amount by compressing with the standard encoding method for binary facsimile, reduce the number of planes to be transmitted, and improve the compression efficiency of each bit plane. Communication time can be shortened.

According to the multi-valued image data transmission device of the third aspect of the invention, the multi-valued image data is divided into the upper bit side and the lower bit side at a predetermined bit position, and the upper bit side is gray-coded and then compressed. It is encoded and transmitted, and the lower bit side is uncompressed after being binarized according to the operator's selection, depending on whether the multi-valued image data has many continuous tone images such as photographs or many images such as characters. Alternatively, since it can be compression-encoded and transmitted by the standard encoding method for binary facsimile, the change point of pixels can be reduced and the compression efficiency can be improved by using the Gray code. If the code amount increases by compressing with the standard facsimile encoding method, it is transmitted without encoding, and the number of planes to be transmitted is reduced, while each bit block is transmitted. It is possible to improve the compression efficiency of over emissions, it is possible to shorten the communication time.

According to the multi-valued image data transmission device of the fourth aspect, it is automatically determined whether the multi-valued image data has many continuous tone images such as photographs or many images such as characters, and the lower bit It is possible to automatically select whether the side is compressed and encoded or transmitted, and it is possible to more appropriately prevent an increase in the code amount by compressing with the standard encoding method for binary facsimile. Thus, the compression efficiency can be further improved.

According to the multi-valued image data transmission device of the fifth aspect of the invention, the multi-valued image data is divided into a high-order bit side and a low-order bit side at a predetermined bit position, and the high-order bit side is gray-coded. Compress and code using the default template using the arithmetic coding method, and then send the data, binarize the lower bit side, and then use the template according to the dither matrix to compress and code using the arithmetic coding method before sending. Therefore, by using the Gray code, it is possible to reduce the change points of the pixels and improve the compression efficiency, and at the same time, simplify the encoding means on the transmission side and the decoding means on the reception side while improving the compression efficiency. It is possible to improve the communication time and shorten the communication time.

According to the multi-valued image data transmission device of the invention described in claim 6, the high-order bit side and the low-order bit side are divided, and the high-order bit side is gray-coded for each pixel.
It is compressed and encoded for each bit plane, and the lower bit side is 2
After being digitized, the multi-valued image data that has been compression-encoded and transmitted can be appropriately decoded and reconstructed.

According to the multi-valued image data transmission device of the invention as defined in claim 7, the high-order bit side and the low-order bit side are divided, and after the high-order bit side is gray-coded for each pixel,
It is compressed and encoded for each bit plane, and the lower bit side is 2
After being digitized, the multi-valued image data that has been transmitted without compression can be appropriately decoded and reconstructed.

According to the multi-valued image data transmission device of the invention described in claim 8, the high-order bit side is divided into the low-order bit side, and the high-order bit side is gray-coded for each pixel.
It is compressed and encoded for each bit plane, and the lower bit side is 2
After being digitized, the multi-valued image data that has been sent uncompressed or compressed and encoded can be appropriately decoded and reconstructed depending on whether it is compression-encoded or uncompressed. .

According to the multi-valued image data transmission device of the invention described in claim 9, the high-order bit side and the low-order bit side are divided, and the high-order bit side is gray-coded for each pixel,
After compression coding is performed using the default first pixel reference template for each bit plane and the lower bit side is binarized by the systematic dither method, the second pixel reference template corresponding to the dither matrix is set. It is possible to appropriately decode and reconstruct multi-valued image data that has been compression-encoded and transmitted.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a multi-valued image data transmission device to which a first embodiment of a multi-valued image data transmission device of the present invention is applied.

FIG. 2 is a conceptual diagram of a bit plane.

FIG. 3 is a diagram showing an example of a 5-bit data dither matrix.

FIG. 4 is a diagram showing an example of a three-line template of a binary image data compression standard.

5 is a diagram showing an example of a template corresponding to the dither matrix of FIG.

FIG. 6 is a block diagram of a main part of a multi-valued image data transmission device to which a second embodiment of the multi-valued image data transmission device of the present invention is applied.

FIG. 7 is a block diagram of a main part of a multi-valued image data transmission device to which a third embodiment of the multi-valued image data transmission device of the present invention is applied.

FIG. 8 is a block diagram of a main part of a multi-valued image data transmission device to which a fourth embodiment of the multi-valued image data transmission device of the present invention is applied.

FIG. 9 is a block diagram of a main part of a multi-valued image data transmission device to which a fifth embodiment of the multi-valued image data transmission device of the present invention is applied.

FIG. 10 is a block diagram of a main part of a multi-valued image data transmission device to which a sixth embodiment of the multi-valued image data transmission device of the present invention is applied.

FIG. 11 is a block diagram of a main part of a multi-valued image data transmission device to which a seventh embodiment of the multi-valued image data transmission device of the present invention is applied.

FIG. 12 is a circuit block diagram of a facsimile device as a conventional multi-valued image data transmission device.

[Explanation of symbols]

 1, 10, 20, 30 Multi-valued image data transmission device 2 Input unit 3 bit plane memories 3a to 3h Storage area 4 Gray coding unit 5 Encoding unit 6 Binarization unit 7 Transmission unit 21 Switching unit 31 Image area separation unit 40, 50, 60 Multi-value image data transmission device 41 Reception unit 42 Decoding unit 43 Natural binary evolution unit 44 Bit plane memory 44a to 44h Storage area 45 Output unit 61 Switching unit BP0 to BP7 Bit plane

Claims (9)

[Claims] 1. A multi-valued image data transmission device, wherein multi-valued image data input from an input means is encoded by a Gray code encoding method and transmitted by a transmission means, wherein the input multi-valued image data is a bit plane. Storage means for expanding the data into bit planes and storing it for each bit plane; gray coding means for gray coding each pixel data of the multi-valued image data expanded in the bit planes in the storage means in the gradation direction; Binarizing means for binarizing the multi-valued image data expanded on the bit plane by the means;
Encoding means for compressing and encoding multi-valued image data, dividing the multi-valued image data expanded into a bit plane in the storage means into a high-order bit side and a low-order bit side at a predetermined bit position, and the high-order bit After the side is gray coded for each pixel by the gray coding means, the coding means compressively codes each bit plane for transmission, and the lower bit side is binarized by the binarization means A multi-valued image data transmission device, wherein the multi-valued image data transmission device is compression-encoded by the encoding means and transmitted. 2. A multi-valued image data transmission device, wherein multi-valued image data input from an input means is encoded by a Gray code encoding method and transmitted by a transmission means, wherein the input multi-valued image data is formed into a bit plane. Storage means for expanding and storing for each bit plane; gray coding means for gray-coding the pixel data of the multi-valued image data expanded on the bit plane in the storage means in the gradation direction; and the storing means. Binarizing means for binarizing the multi-valued image data expanded on the bit plane,
Coding means for compressing and coding multi-valued image data by a binary facsimile standard coding method, wherein the multi-valued image data expanded in a bit plane in the storage means are arranged at a predetermined bit position at a higher bit side and a lower bit side. The bit side is divided, the upper bit side is gray-coded for each pixel by the Gray coding means, and then the coding means compressively codes each bit plane for transmission, and the lower bit side is used for the 2
A multi-valued image data transmission device, characterized in that it is binarized by a binarizing means and then transmitted in an uncompressed state. 3. A multi-valued image data transmission device, wherein multi-valued image data input from an input means is encoded by a Gray code encoding method and transmitted by a transmission means, wherein the input multi-valued image data is formed into a bit plane. Storage means for expanding and storing for each bit plane; gray coding means for gray-coding the pixel data of the multi-valued image data expanded on the bit plane in the storage means in the gradation direction; and the storing means. Binarizing means for binarizing the multi-valued image data expanded on the bit plane,
Encoding means for compressing and encoding multi-valued image data by a binary facsimile standard encoding method, and when the multi-valued image data has many continuous tone images such as photographs, the first mode is selected to select characters or the like. When there are many images, the selection means for selecting the second mode is provided, and the multi-valued image data expanded in the bit plane in the storage means is divided into a high-order bit side and a low-order bit side at a predetermined bit position, The high-order bit side is gray-coded for each pixel by the gray-coding means, and then the coding means compressively codes the bit planes for transmission, and the low-order bit side is processed by the selection means. When the first mode is selected, it is binarized by the binarizing means and then transmitted in an uncompressed state, and when the second mode is selected by the selecting means, the After binarized by binarization unit, multi-level image data transmission apparatus and transmits to compression encoding by said encoding means. 4. A multi-valued image data transmission device, wherein multi-valued image data input from an input means is encoded by a Gray code encoding method and transmitted by a transmission means, wherein the input multi-valued image data is formed into a bit plane. Storage means for expanding and storing for each bit plane; gray coding means for gray-coding the pixel data of the multi-valued image data expanded on the bit plane in the storage means in the gradation direction; and the storing means. Binarizing means for binarizing the multi-valued image data expanded on the bit plane,
Encoding means for compressing and encoding image data by a binary facsimile standard encoding method, and determining whether the multi-valued image data has many continuous tone images such as photographs or many images such as characters to determine the continuous floor. If it is determined that there are many toned images, the first mode is selected, and if it is determined that there are many images such as characters, an image area separation unit that selects the second mode is provided, and the storage unit is expanded to a bit plane. The multi-valued image data thus obtained is divided into a high-order bit side and a low-order bit side at a predetermined bit position, the high-order bit side is gray-coded for each pixel by the gray-coding means, and then the bit-plane is obtained by the coding means. When the image area separation means selects the first mode for the lower bit side, it is binarized by the binarization means and then transmitted in an uncompressed state. Shi When the image area separation means for selecting said second mode of said 2 was binarized by binarization unit, multi-level image data transmission apparatus and transmits to compression encoding by said encoding means. 5. A multi-valued image data transmission device, wherein multi-valued image data input from an input means is encoded by a Gray code encoding method and transmitted by a transmission means, wherein the input multi-valued image data is a bit plane. Storage means for expanding the data into bit planes and storing it for each bit plane; gray coding means for gray coding each pixel data of the multi-valued image data expanded in the bit planes in the storage means in the gradation direction; Means for binarizing the multi-valued image data expanded on the bit plane by a systematic dither method using a predetermined dither matrix; and a default first pixel reference template and the dither matrix. According to the first pixel reference template or the first pixel reference template. Coding means for compressing and coding by the arithmetic coding method using the pixel reference template of No. 2, and the multi-valued image data expanded into bit planes in the storage means at a predetermined bit position on the upper bit side. The lower bit side is divided, and the upper bit side is gray coded for each pixel by the Gray coding means, and then the arithmetic means is coded by the coding means for each bit plane using the first pixel reference template. It is characterized in that the low-order bit side is binarized by the binarizing means, and then is arithmetically coded by the coding means using the second pixel reference template before being transmitted. Multi-value image data transmission device. 6. A multi-valued image data transmission device, which decodes multi-valued image data encoded by the Gray code encoding method received by a reception means, and outputs the decoded multi-valued image data by an output means. Decoding means for decoding the value image data, binarization means for converting the gray code data decoded by the decoding means into natural binary data, and storage means for storing the multivalued image data expanded in bit planes. And is divided into a high-order bit side and a low-order bit side, and the high-order bit side is gray-coded for each pixel,
It is compressed and encoded for each bit plane, and the lower bit side is 2
When the compression-encoded multi-valued image data is transmitted after being digitized, the upper bit side is sequentially decoded by the decoding means and reproduced as bit plane data, and then each pixel data is converted. It is converted to natural binary data by the binarization means, stored in the corresponding bit plane position of the storage means, the lower bit side is decoded by the decoding means, and then stored as bit plane data in the storage means. A multi-valued image data transmission device characterized in that the multi-valued image data is stored in a corresponding bit plane position to reconstruct an image, and the multi-valued image data stored in the storage means is output by the output means. 7. A multi-valued image data transmission apparatus, which decodes multi-valued image data encoded by the Gray code encoding method received by a reception means and outputs the multi-valued image data by an output means, wherein: Decoding means for decoding the value image data, binarization means for converting the gray code data decoded by the decoding means into natural binary data, and storage means for storing the multivalued image data expanded in bit planes. And is divided into a high-order bit side and a low-order bit side, and the high-order bit side is gray-coded for each pixel,
It is compressed and encoded for each bit plane, and the lower bit side is 2
When the non-compressed multi-valued image data is transmitted after being digitized, the upper bit side is sequentially decoded by the decoding means and reproduced as bit plane data, and then each pixel data is converted into The image data is converted into natural binary data by the evolution means and stored in the corresponding bit plane position of the storage means, and the lower bit side is stored as the bit plane data as it is in the corresponding bit plane position of the storage means. A multivalued image data transmission device, characterized in that the multivalued image data reconstructed and stored in the storage means is output by the output means. 8. A multi-valued image data transmission apparatus, which decodes multi-valued image data encoded by the Gray code encoding method received by a reception means and outputs the multi-valued image data by an output means, wherein: Decoding means for decoding the value image data, binarization means for converting the gray code data decoded by the decoding means into natural binary data, and storage means for storing the multivalued image data expanded in bit planes. And a discrimination switching unit that discriminates whether the multi-valued image data received by the receiving unit is compressed data or non-compressed data, and switches between the decoding unit and the storage unit to output. , The high-order bit side and the low-order bit side are divided, the high-order bit side is gray-coded for each pixel, and then compression-coded for each bit plane, and the low-order bit side is binarized. Then, when non-compressed or compression-encoded multi-valued image data is transmitted,
After being sequentially decoded by the decoding means and reproduced as bit plane data, each pixel data is converted into natural binary data by the binarization means and stored in the corresponding bit plane position of the storage means, and the lower bit On the side, when the discrimination switching means outputs the received multi-valued image data to the decoding means, it is decoded by the decoding means and then stored as bit plane data in a corresponding bit plane position of the storage means. Then, when the discrimination switching means outputs the received multi-valued image data as it is to the storage means, it is stored as bit plane data in a corresponding bit plane position of the storage means to reconstruct an image, and the storage means is stored. A multi-valued image data transmission device, wherein the multi-valued image data stored in is output by the output means. 9. A multi-valued image data transmission apparatus, which decodes multi-valued image data encoded by the Gray code encoding method received by the reception means and outputs the multi-valued image data by the output means, for reference of the first pixel by default. A second pixel reference template corresponding to the template and the dither matrix is provided, and the received image data is decoded by an arithmetic decoding method using the first pixel reference template or the second pixel reference template. And a decoding unit for converting the gray code data decoded by the decoding unit into natural binary data, and a storage unit for storing multi-valued image data expanded into bit planes. It is divided into the bit side and the lower bit side, and after the upper bit side is gray-coded for each pixel, it is defaulted for each bit plane. Is compressed and encoded using the first pixel reference template, the lower bit side is binarized by the systematic dither method, and then compressed using the second pixel reference template according to the dither matrix. When the encoded multi-valued image data is transmitted, the upper bit side is sequentially decoded by the decoding means using the first pixel reference template and reproduced as bit plane data, Each pixel data is converted into natural binary data by the binarization means and stored in the corresponding bit plane position of the storage means, and the lower bit side is used by the decoding means with the second pixel reference template. Stored in the corresponding bit plane position of the storage means to reconstruct the image and stored in the storage means. Multivalue image data transmission apparatus and outputs the multilevel image data by said output means.