JPH10285406A - Image processing apparatus and method - Google Patents

Abstract

(57) Abstract: In an image processing apparatus for processing a color image signal composed of a plurality of color components, communication or storage of the color image signal is achieved by easily reducing an enormous amount of data. To reduce the load for. SOLUTION: Four of C, M, Y, Bk inputted as multi-values
Of the color components, the value of Bk is added to adders 11-1, 11-2,
At 11-3, the image data is converted into three color components by adding to the values of C, M, and Y.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image processing apparatus and method, and more particularly, to an image processing apparatus and method for compressing color image data.

[0002]

2. Description of the Related Art In recent years, the development of data communication technology has been remarkable, and accordingly, image processing apparatuses for performing communication and accumulation of image data and realizing so-called multimedia have become widespread. In such an image processing apparatus, in order to process a higher-quality image, it is inevitable that the image needs to be colored and have a higher resolution, and the amount of image data to be processed must be enormous.

For example, when a conventional image processing apparatus handles a color image, a color image is recorded by an additive color mixture method based on the color-separated image signal. That is, Y
(Yellow), M (magenta), C (cyan), Bk
A color image is expressed by obtaining signals for each of the four (black) recording agents and recording the respective colors in a superimposed manner. Then, when communicating or storing this color image signal,
In order to reduce the load on the image processing apparatus, it is usual to reduce the amount of data by performing compression.

In addition, color signals for three colors of Y, M, and C are obtained, and Bk is used for a pixel where all of the three color printing materials overlap.
There is also known an image processing apparatus in which the amount of data to be handled is reduced by recording by replacing with a color recording material. A method of outputting four color signals of Y, M, C, and Bk from three color signals of Y, M, and C will be described below with reference to FIG.

First, the RGB signals read from a scanner or the like are logarithmically converted to obtain the levels of the three color signals C0, M0, and Y0. An example of C0, M0, and Y0 is shown in 8-1. Then, of these three color signals, the color signal having the minimum level value is extracted as the Bk value. This state is shown in 8-2. In the example of FIG. 8, since the Y0 signal has the minimum level, the level value of the Y0 signal becomes the level value of the Bk signal as it is. Then, the value obtained by subtracting the level value of Bk from each level value of C0, M0, Y0 is C,
It is determined as a new level value of M and Y. This state is 8
-3. As described above, the color image signals handled in the apparatus are limited to the three colors of Y, M, and C, and the four color signals of Y, M, C, and Bk are generated based on the three-color signals at the time of output. As a result, the compression processing in the apparatus can be performed for three colors, and the load is reduced.

[0006]

However, in the conventional image processing apparatus, color images obtained by the additive color mixture method are input as image data of four colors of C, M, Y, and Bk, respectively, and are output as image data of the four colors. To output,
Compression processing is individually performed on each color signal to create a compressed image signal for four colors. Therefore, no matter how much a color image is compressed, the data amount is four times as large as that of a monochrome image of the same size, and the load for communication and storage in the image processing apparatus is still large. Met.

Here, the input C, M, Y, Bk 4
By converting color image data into three colors of R (red), G (green), and B (blue) instead of handling the image data as it is, it is also possible to handle the same amount of data as a monochrome image of the same size. is there. As a result, the load of communication and storage in the image processing apparatus is reduced as compared with the case where image data of four colors is handled as it is. However, this method requires a process of converting image data for four colors of C, M, Y, and Bk into three colors of R, G, and B. When the conversion process is realized by software, the processing time is required. Therefore, a large-scale circuit configuration needs to be added in order to realize the hardware.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is possible to simply reduce the data amount of color image data having four color component signals of C, M, Y, and Bk. It is an object of the present invention to provide an image processing apparatus and a method thereof capable of reducing the load of communication or storage.

[0009]

As one means for achieving the above object, the image processing apparatus of the present invention has the following arrangement.

That is, an image processing apparatus for processing a color image signal composed of a plurality of color components, comprising: a data conversion means for performing conversion so as to reduce the number of color components constituting the color image signal; Compression means for compressing the color image signal converted by the means.

In particular, the color image signal is composed of four color components, and the data conversion means converts the color image signal into three color components.

For example, the color component is multi-valued, and the data conversion means adds the value of the first color among the four colors to the value of the other three colors.

For example, the color component is binary, and the data conversion means performs a logical OR of the value of the first color of the four colors and the value of the other three colors.

For example, the color image signal is characterized by comprising color components based on an additive color mixture method.

For example, the color image signal is cyan,
The data conversion means is constituted by four color components of magenta, yellow and black, and the data conversion means converts the color image signal into three color components of cyan, magenta and yellow.

[0016] For example, the first color is black.

Further, as one method for achieving the above object, the image processing method of the present invention includes the following steps.

In other words, there is provided an image processing method for processing a color image signal composed of a plurality of color components, the data conversion step of performing conversion so as to reduce the number of color components constituting the color image signal; And a compression step of compressing the color image signal converted by the step.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below in detail with reference to the drawings.

<First Embodiment>

FIG. 1 shows a block diagram of an image processing apparatus according to the present embodiment. In FIG. 1, 110 is a CCD
An image input unit configured by a scanner or the like, for inputting image data, an image processing unit 111 for performing various image processing including data conversion processing, which is a feature of the present embodiment, and a command input unit 112 such as an operation panel. An operation unit for notifying an operator of the state of the image processing apparatus; 113, an image display unit for displaying image data such as a CRT; 114, a communication unit for transmitting and receiving image data; Is an image output unit that outputs.

Hereinafter, the image processing section 111 of the present embodiment will be described with reference to FIGS.

As described in the above-mentioned conventional example, the RGB signals are inputted to the conventional image processing apparatus and the C, M, Y,
In the case of outputting a Bk four-color image signal, first, as shown in FIG. 8, the RGB signal is logarithmically converted, and the obtained C0, M0, Y0 are obtained.
And the minimum level value of the three color signals of
The remaining values obtained by subtracting the value of Bk from the values of 0, M0, and Y0 are output as the values of C, M, and Y.

In the present embodiment, contrary to the above conventional example, when compressing color image data to be treated as C, M, Y, Bk, the value of Bk is added to C, M, Y, respectively. It is characterized in that the data amount is reduced by substituting three color components.

FIG. 2 is a diagram showing a characteristic configuration of the image processing unit 111. The 8-bit data of each of C, M, Y, and Bk input from the image input unit 110 is converted into three colors of C1, M1, and Y1 in the image data conversion unit 11. The data for the three colors is transferred to the image data compression unit 12.
And output as C2, M2, Y2.
Thereafter, various types of image processing are performed in a processing unit (not shown). After performing the desired image processing on the four color components of C, M, Y, and Bk, the image data may be input to the image data conversion unit 11, or the desired values may be applied to the uncompressed C1, M1, Y1. Of course, a configuration for performing the above image processing is also possible.

FIG. 3 shows a detailed configuration of the image data conversion unit 11 and will be described.

Of the input C, M, Y, and Bk (8-bit signals), the C, M, and Y signals are added to adders 11 respectively.
-1, 11-2, and 11-3. On the other hand, the Bk signal is input to all the adders 11-1, 11-2, and 11-3. Then, each adder 11-1, 11-2, 11-
3, the sum of the C, M, Y signal and the Bk signal is C1, M
1 and Y1 respectively.

FIG. 4 shows a detailed configuration of the image data compression unit 12 and will be described.

In FIG. 4, reference numeral 12-1 denotes a JPEG image compression circuit, which is a JPEG encoding system which is a standard encoding method for a multi-valued image signal input with 8-bit C1, M1, Y1 respectively. Compression by C2, M2,
Output as Y2.

As described above, according to the present embodiment,
When processing multi-valued image data of four colors of C, M, Y, and Bk, image data for three colors of C1, M1, and Y1 may be compressed. , The amount of data to be processed can be reduced as compared to the case where compression is performed.

In the present embodiment, an example has been described in which the image data conversion unit 11 is configured by hardware and realized. However, the same effect can be obtained by calculation processing by software.

Similarly, an example in which the JPEG image compression circuit 12-1 is used as the image data compression unit 12 has been described. However, this may be a circuit that executes compression by another method. Processing can also be performed.

<Second Embodiment>

Hereinafter, a second embodiment according to the present invention will be described.

In the above-described first embodiment, an example in which multi-valued color image signals are handled has been described. In the second embodiment, an example in which C, M, Y, and Bk binary color image signals are handled is described. explain.

Conventionally, a color image 2
When performing value recording, the part to be expressed as Bk is B
It can also be expressed by outputting k single colors or by superimposing and outputting three colors of C, M, and Y.

In the second embodiment, C, M, Y, B
When a binary image signal of k is input, the value of Bk is converted so as to be expressed by superimposing C, M, and Y, that is, the Bk component is replaced with three color components of C, M, and Y. It is characterized by.

The schematic configuration of the image processing apparatus according to the second embodiment is similar to that of the above-described first embodiment shown in FIG.
Description is omitted. Image processing unit 11 in second embodiment
1 is shown in FIG. 5 and will be described below.

C, M, input from the image input unit 110
Each one-bit data of Y and Bk is converted to an image data
Are converted into three colors of C1, M1, and Y1. Then, the data for the three colors is compressed by the image data compression unit 22 and output as C2, M2, and Y2. afterwards,
Various image processing is performed in a processing unit (not shown). still,
After subjecting the four color components of C, M, Y, and Bk to desired image processing, the image data may be input to the image data conversion unit 21,
Of course, a configuration in which desired image processing is performed on C1, M1, and Y1 before compression is also possible.

FIG. 6 shows a detailed configuration of the image data conversion unit 21 and will be described.

Of the input C, M, Y, and Bk (one bit each) signals, the C, M, and Y signals are respectively supplied to the OR circuit 2.
1-1, 21-2, and 21-3. On the other hand, Bk
The signal is input to all the OR circuits 21-1, 21-2, and 21-3. Then, each OR circuit 21-1, 21-2,
From 21-3, the logical sum of the C, M, and Y signals and the Bk signal is output as C1, M1, and Y1, respectively.

FIG. 7 shows a detailed configuration of the image data compression unit 22 and will be described.

In FIG. 7, reference numeral 22-1 denotes a JBIG image compression circuit, which applies a JBIG encoding method, which is a standard encoding method, to a binary image signal input with 1-bit C1, M1, and Y1, respectively. Compression by C2, M2,
Output as Y2.

As described above, according to the second embodiment,
When processing binary image data of four colors of C, M, Y, and Bk, image data of three colors of C1, M1, and Y1 may be compressed. , The amount of data to be processed can be reduced as compared to the case where compression is performed.

In the second embodiment, an example has been described in which the image data conversion unit 11 is configured and implemented by hardware. However, the same effect can be obtained by arithmetic processing using software.

Similarly, an example in which the JBIG image compression circuit 22-1 is used as the image data compression unit 22 has been described. However, this may be a circuit that executes compression by another method. Processing can also be performed.

<Other Embodiments>

Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine, a facsimile, etc.) comprising one device Device).

It is another object of the present invention to provide a system or an apparatus with a storage medium storing a program code of software for realizing the functions of the above-described embodiments, and to provide a computer (or CPU) of the system or the apparatus.
And MPU) read and execute the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided on a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instructions of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0054]

As described above, according to the present invention, the Bk components of the four color component signals of C, M, Y, and Bk are replaced with three color components of C, M, and Y by a simple configuration. By performing compression thereafter, the data amount after compression can be reduced. Therefore, communication of the compressed image data,
Alternatively, it is possible to reduce the load on the image processing device during accumulation.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of an image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of an image processing unit according to the embodiment.

FIG. 3 is a block diagram illustrating a detailed configuration of an image data conversion unit according to the embodiment.

FIG. 4 is a block diagram illustrating a detailed configuration of an image data compression unit according to the embodiment.

FIG. 5 is a block diagram illustrating a schematic configuration of an image processing unit according to a second embodiment of the present invention.

FIG. 6 is a block diagram illustrating a detailed configuration of an image data conversion unit according to a second embodiment.

FIG. 7 is a block diagram illustrating a detailed configuration of an image data compression unit according to a second embodiment.

FIG. 8 is a diagram for explaining a method of generating a CMYBk signal in a conventional image processing apparatus.

[Explanation of symbols]

 11, 21 image data conversion unit 12, 22, image data compression unit 11-1, 11-2, 11-3 adder 21-1, 21, 2, 21-3 OR circuit 111 image processing unit

Claims (14)

[Claims] 1. An image processing apparatus for processing a color image signal composed of a plurality of color components, comprising: data conversion means for performing conversion so as to reduce the number of color components constituting the color image signal; Compression means for compressing the color image signal converted by the means. 2. The image processing apparatus according to claim 1, wherein said color image signal is composed of four color components, and said data conversion means converts said color image signal into three color components. apparatus. 3. The color conversion device according to claim 2, wherein the color component is multi-valued, and the data conversion unit adds a value of a first color among the four colors to a value of the other three colors. Image processing device. 4. The data conversion device according to claim 1, wherein the color component is binary, and the data conversion unit performs a logical sum of a value of a first color of the four colors and a value of the other three colors. 3. The image processing device according to 2. 5. The image processing apparatus according to claim 3, wherein the color image signal is configured by a color component based on an additive color mixture method. 6. The color image signal is composed of four color components of cyan, magenta, yellow, and black, and the data conversion means converts the color image signal into cyan,
6. The image processing apparatus according to claim 5, wherein the image is converted into three color components of magenta and yellow. 7. The image processing apparatus according to claim 6, wherein said first color is black. 8. An image processing apparatus according to claim 3, wherein said compression means performs JPEG compression. 9. The image processing apparatus according to claim 4, wherein said compression means performs compression by JBIG. 10. An image processing method for processing a color image signal composed of a plurality of color components, comprising: a data conversion step of performing conversion so as to reduce the number of color components constituting the color image signal; A compression step of compressing the color image signal converted by the step. 11. The image according to claim 10, wherein said color image signal is composed of four color components, and said data conversion step converts said color image signal into three color components. Processing method. 12. The method according to claim 1, wherein the color component is multi-valued, and in the data conversion step, a value of a first color of the four colors is added to a value of the other three colors.
2. The image processing method according to 1. 13. The data conversion step, wherein in the data conversion step, a logical sum of a value of a first color among four colors and a value of other three colors is obtained. Item 12. The image processing method according to Item 11. 14. The image processing method according to claim 12, wherein the first color is black.