JPH05252404A - Picture information processor - Google Patents

Abstract

PURPOSE:To extract a variation point or an outline of an image, and to compress data with high efficiency by obtaining exclusive OR in order with regard to a picture element to be processed at present and a picture element which is adjacent thereto and is to be processed in the next time. CONSTITUTION:An image reading part 28 contains a one-dimensional image sensor, executes read of picture information on a document, obtains binarized image data, and inputs it to a compressing/expanding circuit part 29. The circuit part 29 obtains exclusive OR between two adjacent picture elements in the main scanning direction. In this case, the picture element to be processed is moved by one picture element each to the right end from the left and at every scanning line, and with regard to the respective picture elements to be processed, exclusive OR to the picture element to be processed in the next time is taken and a signal state is replaced with its result. Accordingly, in the case the signal state of two picture elements is '0' and '1', the state is replaced with image data of '1', and only in the case the signal state in the image data is varied, a variation point consisting of signals '1' of a one-picture element portion is generated, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image information processing apparatus for compressing image data read by an image reading section or expanding the compressed image data, such as a facsimile machine, and particularly to a high resolution. The present invention relates to an image information processing apparatus suitable for compression and expansion of digitized binary image data.

[0002]

2. Description of the Related Art For example, in a facsimile machine, image information on a document is read by an image reading section using a one-dimensional image sensor. CCITT (International Telegraph and Telephone Advisory Committee) stipulates that the image data of a document is composed of pixels arranged on a scanning line. Here, the first scanning line is located at the leading edge of the document and is moved toward the right edge with the left edge as the starting point. The next scan line is located immediately below the previous scan line and is also adapted to move from the left edge to the right edge. The same applies hereinafter. A pixel is a unit area area and is the minimum unit of image information to be read.

The image information of analog level, which represents the shade of each pixel obtained by reading the image, is binarized at a predetermined threshold level. As a result, each scanning line becomes image data in which white or black "runs" alternately appear. Here, "run" means that pixels of the same color are connected to the pixels of the next different color. Black "runs" and white "runs" are always arranged alternately in one scan line, so if the first "run" color is known for each scan line, the subsequent "run" colors will be Determined automatically in order. Therefore, the "run" after the first "run" can be reproduced by only having information (run length) regarding their length (the number of pixels of the same color).

The MH (Modified Huffman) coding method has been well known as a compression method focusing on this point. In addition to this, MR which is an improvement of this MH coding method
There are (Modified Read) coding system and MMR (Modified MR) coding system.

In the MH coding system, a white or black run length on a scanning line is a terminating code showing a run length of "0" to "63" and "64" ×.
Coding is performed in combination with a makeup code indicating the run length of n. In this encoding method, in the case of a run length of "63" or less, encoding is performed using only the terminating code, and when the run length becomes "64" or more, the makeup code and the terminating code are encoded. Encoding is performed as the sum.

As described above, the reason why the encoding is performed only with the terminating code for the run length of "63" or less is that the appearance rate is relatively high and the run length is short. This is because shorter codes are assigned to increase the compression ratio. On the other hand, when the run length is "64" or more, the compression ratio does not decrease so much even when the combined relatively long code is used.

In the MR coding system and the MMR coding system, it is not necessary to pay attention to only the scanning line currently being compressed,
The compression is performed in relation to the adjacent reference line. Since the present invention relates to a compression device that focuses on the scan line itself that is currently being compressed, it is not directly related to these two encoding methods. Therefore, detailed description thereof will be omitted.

FIG. 14 shows an example of a manuscript to be read when an image is read by the MH coding system. It is assumed that the characters A, B, C, D, ... Are written as image information on the original 11 in this example. The arrow 12 represents the main scanning direction as the reading direction of the document 11. A one-dimensional image sensor (not shown) for reading an image is arranged in this direction.
The other arrow 13 represents the sub-scanning direction orthogonal to the main scanning direction.

FIG. 15 shows a state of image data when the character "E" in FIG. 14 is read and binarized. Each of the boxes shown in this figure is a pixel 14. White pixels are represented by a signal "0", for example. In this case, the black pixel is represented by the signal "1".

FIG. 16 is a table showing white run lengths and their code words, and black run lengths and their code words in the MH coding system. For example, the code word in the case where the run length is “4” in which four white pixels are continuous is “1100”, and the code word in the case where the run length is “4” in which four black pixels are continuous is “011”. ..

FIG. 17 shows a state of signal processing when the scanning line indicated by the arrow 15 in FIG. 15 is encoded by the table shown in FIG. Of these, Figure 1
7A shows a state of image information on the scanning line shown by the arrow 15 in FIG. Here, the first 3 pixels are white W, the next 20 pixels are black B, and the remaining 4 pixels are white W again.

FIG. 17B shows image data after the image is read and binarized.
Since it has not been compressed yet, the first three pixels become the signal "0" and the next two pixels
0 pixel is signal “1”, last 4 pixels is signal “0”
It is represented by. FIG. 17C shows a state of the image data after being encoded by the MH encoding method. The run length "3" is represented by white as "1011", the run length "20" is represented by black as "0000100", and the run length "4" is represented as white as "1100". As a result, the 27-bit image data shown in FIG.
Will be encoded as 0000101100.

[0013]

By the way, ISDN
With the spread of (service integrated digital network), an era has arrived where a large amount of data can be transmitted at high speed and at low cost.
Therefore, for example, in a facsimile apparatus, it is expected that not only the transmission time of the original document will be shortened but also the resolution thereof will be significantly improved as compared with the related art.

However, if the same compression method as the conventional one is adopted for the facsimile apparatus having the improved resolution, there is a problem that the compression ratio is difficult to improve. That is, if the resolution is improved by 10 times compared with the conventional one, the run length is increased to “70” even in the image area where the run length is only “7” in the related art, and the termination
It becomes impossible to encode using only the code. That is, most of the run lengths in the scan line are coded as the sum of the makeup code and the terminating code, and the compression ratio is considerably lowered.

Therefore, an object of the present invention is to provide an image information processing apparatus capable of ensuring a high compression rate even if the resolution of image information is improved.

Another object of the present invention is to provide an image information processing apparatus capable of restoring the image data processed at such a high compression rate to the original image information.

[0017]

According to a first aspect of the present invention, image data input means for sequentially inputting binarized image data in pixel units in the scanning direction, and a pixel to be currently processed in this image data. The image information processing apparatus is provided with a logic circuit that performs an exclusive OR with a pixel to be processed next, which is adjacent thereto, and a coding unit that codes the output of the logic circuit.

That is, according to the first aspect of the invention, the exclusive OR of the two adjacent pixels is sequentially taken while shifting the binarized image data pixel by pixel, and the colors of the two adjacent pixels are different ( Change point) is detected. In this way, the contour of the original image is extracted and coded to increase the image data with a run length of 1 pixel, so that a high compression rate can be achieved even if the resolution is improved. And achieve the first objective described above.

According to the second aspect of the present invention, an image obtained by sequentially taking the exclusive OR of the pixel to be currently processed of the binarized image data and the pixel to be processed next adjacent to this pixel. Enter the data in line units, and enter 1 of the specified color.
A change point detecting means for detecting a change point formed of each pixel and each point so that the signal state is alternately inverted when the respective change points detected by the change point detecting means are traced in a predetermined direction. The image information processing device is provided with image information restoring means for restoring the image information by replacing the signal from the following point to a signal of one color.

That is, according to the second aspect of the present invention, the change points forming the contour line of the image are detected, and a signal of one color is supplied from each point to the next point so that the signal state is inverted at each of these change points. By recreating the original image by substituting for, the second objective described above is achieved.

According to a third aspect of the present invention, the reading unit that scans the document line by line to read the image information, and the pixel to be currently processed in the binarized image data read by the reading unit are the same. A logic circuit that takes an exclusive OR with the pixel to be processed next adjacent to this on the line, an encoding means that encodes the output of this logic circuit by a predetermined compression method, and the image data after encoding Transmitting means for transmitting, receiving means for receiving image data similarly processed and transmitted from another device, and inputting the received image data, a change point constituted by one pixel of a predetermined color The change point detecting means for detecting and the first change point and the next change point of each line detected by this change point detecting means are replaced with a signal state other than the signal state immediately before, and thereafter, alternately. Signal There is provided in the image processing apparatus and an image information restoring means to restore the image information from each point to the next point by replacing the color of the signal to invert.

That is, according to the third aspect of the present invention, the reading means for reading the original is provided, and the change point is extracted by taking the exclusive OR of the read image data with the logic circuit, and the output of this logic circuit is obtained. When the encoded image data is encoded and transmitted, and when the encoded image data is received by the same principle, the change points of each scanning line are detected and the desired change points are filled with one color such as black. I decided to reproduce the image information on the manuscript.

[0023]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 shows an outline of a circuit configuration of a facsimile apparatus using a compression apparatus according to an embodiment of the present invention. This facsimile apparatus is a CPU (central processing unit) for executing various processing such as image data compression processing.
It is equipped with 21. The CPU 21 is connected to various circuit devices via a bus 22 such as a data bus.

Of these, the ROM 23 is a read only program that stores a program for controlling compression processing and other general facsimile communication control, and a table representing make-up codes and terminating codes. It is a memory. The working memory 24 is a CPU
Reference numeral 21 is a random access memory for storing data that is temporarily required for executing various operations. The operation panel 25 is a panel for performing a communication operation, and various key switches and a liquid crystal display panel are arranged here. The communication control unit 26 is connected to the line 27 so as to transmit and receive a facsimile signal.

The image reading section 28 has a built-in one-dimensional image sensor and reads image information on a document. The compression / expansion circuit unit 29 is composed of a circuit for compressing or expanding image information. Image recording unit 3
Reference numeral 0 denotes a laser printer, for example, which records received images and the like.

The image reading unit 28 of the image information processing apparatus having such a configuration reads the original 11 shown in FIG. 14 and binarizes the image data of the character "E" as shown in FIG. Shall be obtained. However, here, it is assumed that the image reading density for the character "E" is the same as the conventional one.

FIG. 2 shows image data obtained as a result of inputting this image data to the compression / decompression circuit section shown in FIG. 1 and taking an exclusive OR between two adjacent pixels in the main scanning direction. It is a thing. The pixel to be processed is moved one pixel at a time from the left end to the right end for each scanning line, and the exclusive OR of each pixel to be processed with the pixel to be processed next is calculated, and the result is signal state. To be replaced. That is, when the signal states of the two pixels that take the exclusive OR are divided into two states of “0” and “1”, the signal state is replaced with the image data of “1” (black), and other In this case, the signal state is replaced with image data of "0" (white). In this way, the change points each consisting of the signal "1" for one pixel appear only at the places where the signal state in the image data changes.

FIG. 3 shows a table for encoding the image data thus obtained.
This table is basically the same as the table shown in FIG. 16 with respect to the white run length. As for the black run length, only the data of the run length "1" appears at each change point as shown in FIG. 2, so this is represented by the data "1" of the shortest bit length.

FIG. 4 shows the state of signal processing when the scanning line indicated by the arrow 35 in FIG. 2 is encoded by the table shown in FIG. Of these, Figure 4
(A) shows the state of the image data converted by the table in this scanning line. Here, the first two pixels are white W, and the next one pixel is black B as a change point. The next 19 pixels are originally black, but are replaced by white W. Next, there is a black color B as a change point for one pixel, and the remaining four pixels are the original white color W
Is.

FIG. 4B shows a signal waveform of this image data. Image data of white W is signal “0”
The black B image data is represented by the signal "1". FIG. 4C shows a state of the image data after being encoded using the table shown in FIG. The run length "2" has a white color of "1000", the run length "1" has a black color of "1", and the run length "19" has a white color of "10", and the next run length "1".
The black color is represented by "1", and the white color of the last run length "4" is represented by "1100". As a result, the 27-bit image data shown in FIG. 9B is eventually encoded into the 12-bit image data "100011011100".

In this example, when the character "E" was encoded, the compression process was performed on the assumption that the resolution was the same as the conventional one. However, even if the resolution is improved, the "edge" of the black image portion is used in this embodiment. Are extracted as change points, and these are displayed as 1-bit signals. Therefore, when the resolution is improved, compression is performed at a higher ratio than in the conventional case.

FIG. 5 extracts the change points as shown in FIG.
Is a configuration of a change point extraction circuit for
It The compression / expansion circuit unit 29 shown in FIG.
(N-1) exclusive OR gate 41₁, 41₂, ……
41_n-1Are arranged. These have the same scan line
The image data P of two pixels adjacent to each other is input at
It has become so. Here, the first exclusive OR gate
To 41₁Is the image data P of the first pixel.₁And the second picture
Raw image data P₂Is input, the second exclusive OR
41₂Is the image data P of the second pixel.₂And the third
Pixel image data P ₃Is entered. Similarly below
(N-1) exclusive OR gate 41_n-1In the (n
-1) Pixel image data P_n-1And the image data of the nth pixel
Data P_nIs entered.

It should be noted that the numerical value n does not have to be equal to all pixels for each scan line, and may be a predetermined numerical value smaller than this. In this case, the image data of one scanning line is divided into several pieces, which are sequentially input to the change point extraction circuit shown in FIG. 5 to perform data processing for each n pixels. Now, suppose that the numerical value n is "27" which corresponds to the number of pixels of the scanning line in the area shown in FIG.
Assuming that 1 ₁ , 41 ₂ , ... 41 _n-1 take an exclusive OR, a logical result consisting of a combination of “0” or “1” as shown at the right end of FIG. 5 can be obtained. become.

In this way, the image data after the change point is detected is encoded by the table shown in FIG. 3, and the communication control unit 26 shown in FIG.
7 and is transmitted to the facsimile machine (not shown) on the other side.

FIG. 6 shows the flow of processing of the image information processing apparatus during such image transmission. Figure 1
When receiving the instruction to prepare the transmission of the original document, the CPU 21 shown by means of the image reading unit 28 reads an image for one line, binarizes the image, and expands it in the working memory 24 (step S101). Then, the image data is divided into image data of a predetermined length, which are sequentially input to the change point extraction circuit shown in FIG. 5 and replaced with image data obtained by exclusive OR (EXOR) (step S102). When the processing for one line is completed in this way, this operation is repeated until the processing for all main scanning lines for one page is completed (step S103).

When the image data for one page is created,
A white run length and a black run length are extracted from the image data of each line (step S104). Then, those run lengths are encoded using the table of FIG. 3 (step S105). The encoded image data for one page is accumulated in the work memory 24 until it is transmitted.

When the encoding of the image data for one page is completed in this way, the CPU 21 determines whether or not the next page (original) to be transmitted exists (step S10).
6) If it exists (Y), the process returns to step S101 to process the page. When the processing of all pages is completed (step S106; Y), the preparation for transmission is completed (END).

FIG. 7 shows a flow of decompression processing for one page when a facsimile signal subjected to such coding processing is received. The reception data received by the communication control unit 26 is expanded by one line by the compression / expansion circuit unit 29 while referring to the table shown in FIG. 3 (step S201), and then one bit (black) on the same line. Every other area sandwiched by is painted black (step S202). At this time, the first part of one line is processed as a white pixel. The filling process will be described later in detail.

When the filling of the answer portion on one line is completed, the CPU 21 checks whether or not the same processing has been completed for the processing of all the lines on one page (step S203), and if not completed, step S20.
The process returns to 1 and the next one line is processed. In this way, the expansion process for one page is completed (END). When a plurality of pages are received, the processing shown in FIG. 7 is repeated for that page.

By the way, the image data to be processed by the above expansion processing is a serial data string composed of the signal "0" or the signal "1". In this data string, as is clear from the table shown in FIG. 3, the length of the bit string corresponding to one color is not always constant. Therefore,
A description will be given of at which position these are separated and reproduced as image data in association with the table.

The code words shown in the table shown in FIG. 3 are unique to each other, and the same code word does not appear in other colors or run lengths. In this embodiment, each scan line starts from a white pixel, and is sequentially repeated black, white, black, and white. When decompressing the image data, the table of FIG. 3 is referred to bit by bit from the leading bit in order, and the time when the unmatched bits appear is set as the boundary between the white and black pixels.

FIG. 8 shows the relationship between certain image information and its compressed data as an example. Here, the principle will be described separately from the table shown in FIG. Figure 8
(A) shows the state of the read pixels. The first three are white pixels W, the next four are black pixels B, and the next four are white pixels W. FIG. 2B shows the compressed data obtained by this.

FIGS. 9 and 10 show the principle of referring to the table when decompressing the compressed data.
In these figures, the left half of the table 51 (different from the table of FIG. 3) represents the tree structure as the system of black code words, and the right half represents the tree structure as the system of white code words. ing. In these tree structures, the individual signal states forming the word are searched in order from the top of them. The dashed line 52 indicates that the tree is broken at those positions.

Since the head of the compressed data is the signal "1" in FIG. 8B, the right half white code word is referred to in the first stage shown in FIG. And "1", "0",
Since the tree is interrupted by the fourth signal by sequentially tracing "1" and "1", it is determined that the run length is white indicated by the four code words "1011".

Turning now to FIG. 10, the black codeword, which is now located in the left half, is referenced. In this case,
Since the tree is interrupted by the third signal by going through “0”, “1”, “1” in order, three code words “01”
It is determined to be a black run length indicated by 1 ". Next, the white code word located in the right half is referred to. In this way, the length of each word is different. Even white and black run lengths can be reproduced.

The system of code words in the general table 51 different from the table of FIG. 3 has been described above. In this example, the head is the signal "0" for the black run length, and the head is the signal "1" for black.
When it is known how many run lengths the scan line is composed of, the relationship between the signal state at the beginning and the color does not necessarily have to be set to one-to-one. In the table shown in FIG. 3, the code word when the black run length is "1" is "1", but the code words of the other black run lengths all start from the signal "0". Therefore, it can be distinguished from other code words.

By the way, whether or not the extraction of the changing point or the black contour and the restoration of the image information described above are performed regardless of the number of consecutive pixels of the same color on the scanning line is a problem. This is a problem as to whether or not the image is correctly reproduced even when the image reading unit 28 reads a thin line that originally has only one pixel. Therefore, while comparing this with the case of normal image data, it is verified that the image information processing apparatus of the present embodiment operates without any problem.

FIG. 11 shows how the image data is processed in a normal case where three or more pixels are continuous. In this example, the image information of a certain scanning line is white for the first and second pixels as shown in FIG.
The th pixel ~ is black, the sixth and seventh pixels are,
Is white. That is, in this example, three black pixels are consecutive.

The compression / expansion circuit unit 29 shown in FIG. 1 takes an exclusive OR for each adjacent pixel, and as a result, obtains image data as shown in FIG. In this state, the image data is compressed using the table of FIG. 3 and expanded when the image information is reproduced ((c) and (d) in FIG. 3), and the image data as shown in (e) in FIG. can get. If this is filled in, the original image information is reproduced as shown in FIG. However, the filling process here does not simply fill the signal “0” sandwiched between the signals “1” as described above, but the first signal “1” is converted into white image information. The replacement process is performed.

FIG. 12 shows how the image data is processed when two pixels are continuous. In this example, the image information of a certain scanning line is, as shown in FIG. 7A, the first and second pixels, white is the third pixel, the fourth pixel is the black, and the fifth to seventh pixels ~ Is white.
That is, in this example, two black pixels are continuous. In this figure, (a) to (f) show the same processing steps as shown in FIG. Thus, also in this case, two consecutive black pixels are reproduced without fail.

Finally, FIG. 13 shows how the image data is processed when one pixel is isolated. In this example, the image information of a certain scanning line is, as shown in FIG. 3A, that the first to third pixels are white, the fourth pixel is black, and the fifth to seventh pixels are white. is there. That is, in this example, only one black pixel is isolated. Also in this figure, (a) to (f) represent the same processing steps as shown in FIG. Thus, in this case too, the black one
One pixel is accurately reproduced without disappearing or stretching.

In the above-described embodiments, the facsimile apparatus is taken as an example of the image information processing apparatus, but the image data is compressed and stored in a file, and if necessary, this is read and the original image is reproduced. It goes without saying that the present invention can be similarly applied to such other image information processing apparatuses. Further, although the embodiment has been described by taking the MH coding method as an example, it goes without saying that the present invention can be similarly applied to other coding methods.

[0054]

As described above, according to the invention described in claim 1, 2
Since the binarized image data is sequentially input pixel by pixel in the scanning direction, and the pixel to be currently processed and the pixel to be processed next adjacent to this pixel are exclusively ORed in order, the image change Points or contours can be extracted. Therefore, when encoding this, by setting the length of the code corresponding to the change point to be short, the data can be compressed with high efficiency.

According to the second aspect of the present invention, the change points composed of predetermined one pixel are detected, and the signal states are alternately inverted when the respective change points are traced in the predetermined direction. Since the processing from each point to the next point is replaced with the signal of one color, the compressed binary image data can be accurately restored to the original image data.

According to the third aspect of the invention, the pixel to be processed next in the same line as the pixel to be processed in the image data read and binarized by the reading means is exclusive to the pixel to be processed next. While taking the logical sum and encoding and transmitting this, the image data after such encoding processing is received, the change point composed of one pixel of a predetermined color is detected, and the first of each line is detected. Replace between the change point and the next change point with a signal state other than the signal state immediately before it,
From this point onward, the image information is restored by replacing each point to the next point with a signal of one color so that the signal states are alternately inverted, so image data can be transmitted and received with a smaller amount of information. Therefore, it is possible to reduce the communication cost and the communication time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a circuit configuration of an image information processing apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing image data after an exclusive OR is performed on a binary image in which a character “E” is read in the present embodiment.

FIG. 3 is an explanatory diagram showing contents of a table used for compressing and decompressing image data in this embodiment.

FIG. 4 is an explanatory diagram showing a state of signal processing at the time of encoding a scanning line according to the present embodiment.

FIG. 5 is a circuit diagram showing a configuration of a change point extraction circuit in this embodiment.

FIG. 6 is a flowchart showing a processing flow of the image information processing apparatus at the time of image transmission in this embodiment.

FIG. 7 is a flowchart showing a flow of decompression processing for one page when a facsimile signal subjected to the coding processing in this embodiment is received.

FIG. 8 is an explanatory diagram showing the relationship between certain image information and its compressed data.

9 is an explanatory diagram showing a state of referring to a table in the first stage in the example shown in FIG.

10 is an explanatory diagram showing a state of table reference in the second stage in the example shown in FIG.

FIG. 11 is an explanatory diagram showing a process of image data processing in a normal case where three or more pixels are continuous in the present embodiment.

FIG. 12 is an explanatory diagram showing a process of processing image data when two or more pixels are continuous in the present embodiment.

FIG. 13 is an explanatory diagram showing a process of processing image data when one pixel is isolated in the present embodiment.

FIG. 14 is a plan view showing an example of an original document to be read when an image is read by the MH encoding method.

FIG. 15 is an explanatory diagram showing a state of image data when the character “E” in FIG. 14 is read and binarized.

FIG. 16 is an explanatory diagram showing the contents of a conventionally used table in the MH encoding system.

17 is an explanatory diagram showing a state of signal processing when encoding is performed using the table shown in FIG.

[Explanation of symbols]

21 ... CPU, 23 ... ROM, 24 ... Working memory, 2
5 ... Operation panel, 26 ... Communication control section, 28 ... Image reading section, 29 ... Compression / expansion circuit section, 41 ... Exclusive OR gate, B ... Black pixel, W ... White pixel

Claims (3)

[Claims] 1. An image data input means for sequentially inputting binarized image data in the scanning direction pixel by pixel, a pixel to be currently processed in this image data and a pixel to be processed next adjacent to the pixel. An image information processing apparatus comprising: a logic circuit that takes an exclusive OR, and a coding unit that codes an output of the logic circuit. 2. The image data obtained by sequentially taking the exclusive OR of the pixel to be currently processed of the binarized image data and the pixel to be processed next adjacent thereto is input in line units. Then, a change point detecting means for detecting a change point composed of one pixel of a predetermined color, and a signal state alternately inverted when the respective change points detected by the change point detecting means are traced in a predetermined direction. As described above, the image information restoration device that restores image information by replacing each point to the next point with a signal of one color. 3. A reading unit that scans an original document line by line to read image information, and a pixel to be currently processed in the image data read by the reading unit and binarized is adjacent to the reading line on the same line. A logic circuit that takes an exclusive OR with the pixel to be processed next, a coding means that codes the output of this logic circuit by a predetermined compression method, and a transmission means that transmits the image data after coding, Receiving means for receiving the image data after the encoding processing, changing point detecting means for inputting the received image data, and detecting changing points each constituted by one pixel of a predetermined color, and this changing point detecting means Replace the signal state between the first transition point and the next transition point of each line detected by the above with a signal state other than the signal state immediately before, and after that, change the signal state alternately from the next to the next. To the point 2. An image information processing apparatus, comprising: an image information restoring unit that restores the image information by replacing (1) with a signal of one color.