JP2003018400A - Facsimile terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a facsimile terminal that cannot lose reproducibility of an original image even when reducing the stored image. SOLUTION: In this invention, when an image stored in a memory is reduced 50%, an original pixel of the image is referenced in the main scanning direction by using 2-bit for one set, when a referenced combination pattern is the same as a reference pixel pattern with a combination of different pixels appeared precedingly, pixels of kinds different from a precedingly selected pixel is selected and reduced to half, then even when a reference pattern comprising different pixels consecutively appears, consecutive selection of the same pixel cannot be caused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile machine having an image reduction function.

[0002]

2. Description of the Related Art Conventionally, when transmitting data to a memory in a facsimile apparatus of this type, the original is read by the transmitting side before the call is made and the image is stored in the memory, so that the image cannot be processed according to the capability of the other party. . Therefore, the resolution of the image read on the transmission side may exceed the capability of the other device. For example, the transmission side may store images at 400 dpi main scanning, while the other device may only have 200 dpi main scanning capability. In this case, on the transmitting side, it is necessary to reduce the image of 400 dpi accumulated in the memory by 50% and convert it into the image of main scanning 200 dpi.

With respect to this reduction method, simple thinning out is performed by simply thinning out a pixel located first among two consecutive pixels,
There are reduction methods such as white holding to thin out white pixels when two adjacent pixels have different values, black thinning to hold black pixels when two adjacent pixels have different values, and the like. .

However, in the case of these reduction systems, as a result of converting the read image data into binary data, "010101"
If a "01" pattern occurs in the image, it is simply "111".
1) or "0000." As described above, since the image data after reduction is all white or all black, the fidelity to the original image is significantly impaired.

Therefore, in order to prevent such inconvenience, a reduction system called random thinning out is employed which randomly decides which one of two consecutive pixels is thinned out. According to the random thinning, pixels are thinned out irregularly, so that it is possible to avoid that the image resulting from the reduction becomes an image of all white or all black.

[0006]

However, according to such a conventional technique, the following problems occur.

That is, according to the random thinning, since no consideration is given to maintaining the black ratio or the white ratio of the original image, the black ratio or the white ratio is different between the original image and the reduced image, and the fidelity to the original image is impaired. There is a problem.

Further, according to the random thinning, it is necessary to add a process for randomly thinning. If a dedicated random circuit for random thinning is provided, not only the processing man-hour but also the hardware configuration becomes complicated.
In addition, when the random circuit is configured by ASIC, the number of gates increases.

Further, when the random processing is performed by software, there is a problem that the load on the CPU increases, the processing time increases, and the processing performance decreases.

Therefore, an object of the present invention is to prevent the reproducibility of an original image from being impaired even if the accumulated image is reduced.

[0011]

According to the present invention, when an image stored in a memory is reduced by 50%, a reference pattern in which the original pixel of the image is a set of two pixels in the main scanning direction is referred to. Is the same as the reference pixel pattern of the combination of different pixels that appeared last time, a pixel of a different type from the previously selected pixel is selected and reduced to 1/2.

As a result, even if reference patterns composed of different pixels appear consecutively, the same pixel will not be consecutively selected. Therefore, even if the accumulated image is reduced, the reproducibility with respect to the original image can be maintained.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the facsimile apparatus according to the first aspect of the present invention, when reducing an image stored in a memory by 50%, the original pixel of the image is referred to as a set of two pixels in the main scanning direction. Referring to the pattern, if the reference pattern is a combination of the same pixel, select one of the pixels,
In the case where the reference pattern is a combination of different pixels, one of the pixels is selected, and then the reference pattern is composed of a combination of different pixels, and the combination of the different pixels is the same as the combination of the different pixels that previously appeared. When it appears, a pixel of a type different from the selected pixel from the reference pattern of the combination of different pixels that appeared last time is selected from the reference pattern of the combination of different pixels that appears this time, and 1 /
A configuration including an image reducing means for reducing to 2 is adopted.

With this configuration, the periodicity of the bit pattern of the original image can be maintained almost completely. Therefore, the fidelity to the original image can be maintained at 50% while maintaining the fidelity to the original image with simple software or hardware.
Reduction can be performed.

In the facsimile apparatus according to the second aspect of the present invention, when the main scanning resolution of the image stored in the memory prior to making a call is twice the main scanning resolution of the partner machine determined by the communication procedure, A reference pattern in which the original pixel of the image is a set of two pixels in the main scanning direction is referred to, and when the reference pattern is a combination of the same pixels, one of the pixels is selected, while the reference pattern is a different pixel. In the case of selecting one of the pixels in the case of the combination of, and thereafter consisting of a combination of different pixels, the combination of the different pixels, when the reference pattern that is the same as the combination of the different pixels that appeared last time appears, A pixel of a type different from the selected pixel from the reference pattern of the combination of different pixels that appeared last time is selected from the reference pattern of the combination of different pixels that appears this time, and reduced to 1/2. A configuration provided with the image reduction means that.

With this structure, the periodicity of the bit pattern of the original image can be maintained almost completely, so that the fidelity to the original image can be maintained by 50% while maintaining the fidelity to the original image with simple software or hardware.
Reduction can be performed.

In the facsimile apparatus according to the third aspect of the present invention, the image stored in the memory is 50% to 100%.
In the case of reducing with a reduction ratio between the above-mentioned reduction ratios, the thinning-out pixels that are the thinning-out determination target are determined from the reduction ratio, and a reference pattern in which two pixels of the above-mentioned thinning-out pixel and an adjacent pixel are set is referred to, and the reference pattern is the same. In the case of a combination of pixels, one of the pixels is selected, while in the case where the reference pattern is a combination of different pixels, one of the pixels is selected, and then the combination of different pixels is formed. When the reference pattern that is the same as the combination of different pixels that appeared last time appears, the different pixel that appears this time as a pixel of a different type from the selected pixel from the reference pattern of the combination of different pixels that appeared last time The reference pattern of the combination is selected, and the image reduction means for reducing from 50% to 100% is provided.

With this configuration, when thinning out one pixel from a combination of two different pixels, black pixels and white pixels are always thinned out alternately without thinning out pixels of the same type continuously in the same pattern. It is possible to reduce the size with software or hardware while maintaining the fidelity to the original image.

In the facsimile apparatus according to the fourth aspect of the present invention, when the main scanning resolution of the image stored in the memory prior to making a call is 1 to 2 times the main scanning resolution of the partner machine determined by the communication procedure. , Determining a reduction ratio based on the relationship of the main scanning resolution, determining a thinning pixel to be a thinning determination target from the reduction ratio, and referring to a reference pattern in which two pixels of the thinning pixel and an adjacent pixel are a set, When the reference pattern is a combination of the same pixels, either one of the pixels is selected, while when the reference pattern is a combination of different pixels, either one of the pixels is selected, and then the combination of different pixels is formed. When the reference pattern in which the combination of different pixels is the same as the combination of the different pixels that appeared last time appears, a selection image from the reference pattern of the combination of different pixels that appeared last time The appeared time a different type of pixel and by selecting from the reference pattern of the combination of the different pixels, a configuration provided with the image reduction means for reducing 50% to 100%.

With this configuration, when thinning out one pixel from a combination of two different pixels, black pixels and white pixels are always thinned out alternately without thinning out pixels of the same type continuously in the same pattern. It is possible to reduce the size with software or hardware while maintaining the fidelity to the original image.

According to a fifth aspect of the present invention, in the facsimile apparatus according to any one of the first to fourth aspects, the image reduction means uses the reference pattern of the combination of different pixels that has appeared this time last time. When the reference pattern of the combination of different pixels that appears is different, the first pixel of the reference pattern of the combination of different pixels is selected.

As a result, when the reference pattern of the combination of different pixels that appears this time is different from the reference pattern of the combination of different pixels that appeared last time, the thinned pixel is set as the first pixel regardless of which type of pixel was thinned last time. By doing so, when the reference pattern of the combination of different pixels is different from the previous reference pattern, the black pixel and the white pixel are alternately selected. Therefore, the balance between the white ratio and the black ratio in the original image can be maintained in the reduced image, and the fidelity to the original image can be maintained.

According to a sixth aspect of the present invention, in the facsimile apparatus according to any one of the first to fifth aspects, there is provided holding means for holding a reference pattern of the combination of different pixels that appeared last time. When the reference pattern of the combination of different pixels appears, the image reducing unit refers to the holding unit, and the reference pattern of the combination of different pixels that appears this time is the reference pattern of the combination of different pixels that appeared last time. It is determined whether or not the combination is the same.

By thus referring to the holding means, it is possible to easily determine whether or not the reference pattern of the combination of different pixels that appears this time is the same as the reference pattern of the combination of different pixels that appeared last time.

According to a seventh aspect of the present invention, in the facsimile apparatus according to the sixth aspect, the holding means holds the reference pattern of the same pixel combination as an initial value,
When the reference pattern of the combination of different pixels appears, the image reducing unit refers to the holding unit to set the reference pattern of the combination of different pixels that appears this time to the reference pattern of the combination of different pixels that first appears. Recognized as a reference pattern,
The first pixel of the reference pattern of the combination of different pixels is selected.

In this way, by holding the combination of the same pixel values in the holding means, even if a reference pattern of any combination of different pixels first appears, this reference pattern is irrelevant regardless of the combination. It is possible to reduce the image by recognizing that the first appears and thinning out the leading pixel.

According to an eighth aspect of the present invention, in the facsimile apparatus according to any one of the first to seventh aspects, a pixel holding for holding a pixel thinned out from a reference pattern of the combination of different pixels that appeared last time. If the reference pattern of the combination of different pixels that appears this time is the same as the combination pattern of the reference patterns of the combination of different pixels that appeared last time, the image reduction device includes a pixel held in the pixel holding unit. Is selected as an effective pixel.

As a result, the pixel to be selected as the effective pixel this time can be easily selected, and the image reduction processing can be speeded up.

In a ninth aspect of the present invention, when the image stored in the memory is reduced by 50%, the original pattern of the image is referred to as a set of two pixels in the main scanning direction. Is a combination of the same pixels, either one of the pixels is selected. On the other hand, when the reference pattern is a combination of different pixels, either one of the pixels is selected, and then the combination of different pixels is selected. When the reference pattern whose combination is the same as the combination of different pixels that appeared last time appears, a pixel of a type different from the selected pixel from the reference pattern of the combination of different pixels that appeared last time appears this time. This is an image reducing method of selecting from the reference patterns of combinations of different pixels and reducing it to 1/2.

The configuration of the facsimile apparatus according to the embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a block diagram of a facsimile apparatus according to the above embodiment.

The facsimile apparatus 100 is provided with a CPU 101 which performs a predetermined process based on a program stored in a storage means. The CPU 101 controls various processing units included in the facsimile device 100.

Further, the facsimile apparatus 100 has an RO for storing programs and various settings as a storage means.
An M102, a work memory 104 for temporarily storing image data sent from another terminal, a temporary storage for image data sent to another terminal, and an image memory 103 for storing encoded image data are provided. Has been.

Further, the facsimile machine 100 is provided with a MODEM 105 for transmitting / receiving image data to / from another terminal. The MODEM 105 transmits / receives image data according to a facsimile procedure.

Further, the facsimile apparatus 100 has a MO
A scanner 106 for reading image data to be sent to another terminal via the DEM 105 from a document and a reading control circuit 107 for controlling the scanner 106 are provided. The scanner 106 outputs the optically read image data as analog data, and the reading control circuit 107 converts the analog data into multivalued digital image data and performs image processing such as shading correction. After that, the reading control circuit 107 converts the binary image data and outputs it. Then, the binary image data generated by the reading control circuit 107 is sent to the work memory 104 and temporarily stored therein.

Further, the facsimile apparatus 100 has a MO
A printing device 108 that records image data sent from another terminal via the DEM 105 and a recording control circuit 109 that controls the printing device 108 are provided.

Further, the facsimile apparatus 100 is provided with a CODEC 110 which encodes raw image data and decodes the encoded image data. CODEC
Reference numeral 110 encodes raw image data stored in the work memory 104, or encodes image data sent from an image reduction unit 111 described later. In addition, the image memory 10
Decode the encoded image data stored in 3,
It is sent to the image reduction unit 111 or the work memory 104.

Further, the facsimile apparatus 100 has an AS
An image reduction unit 111 composed of an IC is provided.
When the image reduction unit 111 sends image data read by the scanner 106 to another terminal, the image processing capability of the other terminal is inferior to the image processing capability of the facsimile apparatus 100, and the resolution of the image data to be sent is low. This is to reduce the resolution of image data to be sent when the processing capacity of another terminal is exceeded.

The image reduction unit 111 refers to a reference pattern in which two original pixels included in the sent image data in the main scanning direction (two bits because image data is binary data in this embodiment) are set as a set. However, if the reference pattern is a combination of the same pixels, the determination processing unit 112 that selects the first pixel is provided. On the other hand, the determination processing unit 112
In case of a combination of pixels having different reference patterns, either one of the pixels is selected. Specifically, the determination processing unit 11
When the combination of different pixels appears in the reference pattern, it is judged whether the pattern of the combination is the same as the pattern of the different pixel that appeared last time. Then, the determination processing unit 112
If the reference pattern that appears this time is the same as the reference pattern that appeared last time, a pixel of a type different from the selected pixel of the reference pattern that appeared last time is selected. If the reference pattern that appears this time is different from the pattern that appeared last time, the determination processing unit 112 selects the first pixel of the reference pattern.

Further, the image reducing section 111 is provided with a pattern holding section 113 for holding a reference pattern composed of a combination of different pixels that appeared last time. The pattern holding unit 113 holds a combination of the same pixels, which is “00” as an initial value.

Further, in the image reducing unit 111, when a reference pattern composed of a combination of different pixels (hereinafter referred to as a reference pattern of different pixels) appears, it is not selected, that is, the pixel holding unit 114 that holds thinned pixels. Is provided.

As described above, since the pattern holding unit 113 is provided in the image reducing unit 111, the judgment processing unit 112 is provided.
When a reference pattern of a different pixel appears, it is possible to easily determine whether the reference pattern of the different pixel that appears this time is the same as the reference pattern that appeared last time by referring to the pattern holding unit 113.

Further, the pixel holding unit 1 is added to the image reducing unit 111.
14 is provided, the determination processing unit 112, when the reference pattern of the different pixel that appears this time is the same as the reference pattern of the different pixel that appears last time, the pixel holding unit 114.
By referring to, a pixel different from the pixel selected last time can be recognized, so that a pixel value different from the previous time can be easily selected this time.

Further, by referring to the pattern holding unit 113, the judgment processing unit 112 can easily judge that the reference pattern of the different pixel that appears this time is different from the reference pattern of the different pixel that appeared last time. When the reference pattern of the different pixel that appears this time is different from the reference pattern of the different pixel that appeared last time, the determination processing unit 112 selects the first pixel of the reference pattern of the different pixel that appears this time.

Since the pattern holding unit 113 holds a combination of "00" pixels as an initial value, when a reference pattern of a different pixel appears for the first time, the reference pattern of the different pixel that appears appears in the pattern holding unit. It is always different from the reference pattern held in 113. Therefore, the determination processing unit 11
2 is different from the reference pattern held in the pattern holding unit 113 even when the reference pattern of the different pixel appears for the first time, so that the first pixel of the reference pattern of the different pixel can be selected.

In this way, the image reduction unit 111 reduces the resolution of image data.

Next, the image data transmission process of the facsimile apparatus 100 configured as described above will be described with reference to FIG. FIG. 2 is a flow chart of image data transmission processing of the facsimile apparatus according to the above embodiment. In addition,
FIG. 2 is a processing flow chart when image data is reduced and transmitted.

When the operator places an original on the scanner 106 and gives an instruction for memory transmission, the scanner 106 reads the image data of the original, and the reading control circuit 107 converts the image data into binary data and the work memory 104.
Send to. When the image data is stored in the work memory 104, the image data stored in the work memory 104 is sent to the CODEC 110. And CODEC11
0 encodes the sent image data, and the image memory 1
Send to 03. In this way, the image data is encoded in advance and stored in the image memory 103 before calling.

Next, the facsimile apparatus 100 makes a call to the partner machine and grasps the capability of the partner machine in the communication procedure. When the resolution of the image data stored in the image memory 103 is higher than the resolution of the other device, it becomes necessary to reduce the image data according to the resolution of the other device. Therefore, the encoded image data accumulated in the image memory 103 is transmitted to the CODEC 110 to be decoded, and the image data that has been decoded is sequentially transferred to the image reduction unit 111 line by line (ST201).

Next, the image reduction unit 111 performs plate conversion (reduction conversion) processing on the transmitted image data line by line, and transmits the processed image data to the CODEC 110 (ST202). The details of the reduction conversion process performed by the image reduction unit 111 will be described later.

Next, the CODEC 110 encodes the line for which the plate conversion processing has been completed, and sequentially transfers the image data of the encoded line to the work memory 104 (ST20).
3). Next, the work memory 104 accumulates the encoded image data of the line, and when the accumulation is completed, the MODEM is sequentially operated.
105 to 105. Then, the MODEM 105 transmits the transmitted image data to another terminal (ST20).
4).

When the transmission of the image data of one line is completed in this way, the facsimile apparatus 100 next
Judge whether the transmission is completed up to the last line of the page (ST
205), if not completed, the process proceeds to ST201 and the remaining lines are transmitted. On the other hand, ST205
If the transmission is completed up to the last line in step ST1, it is determined whether the transmission is completed up to the last page of the document (ST20
6) If not completed, the process proceeds to ST201 and the process for the remaining pages. On the other hand, in ST206, when the transmission up to the final page is completed, the memory transmission process is completed.

Next, the image reduction processing performed by the image reduction unit 111 in ST202 will be described in detail with reference to FIG. FIG. 3 is an operation flow diagram of the image reducing unit according to the above embodiment.

When the one-line reduction process is started, the image reduction unit 111 sets the reference pattern held in the pattern holding unit 113 to 00, and sets the thinned pixel value held in the pixel holding unit 114 to 0. The generated reference pattern and the held thinned pixels are cleared (ST301).

Next, the judgment processing section 11 of the image reducing section 111.
2 sets the first pixel of one line as the pixel to be processed (ST302). Furthermore, the determination processing unit 112 determines ST3.
The processed pixel set in 02 and the next 2 pixels (2
bit) as a set and the combination of the pixel values as a reference pattern (ST303).

The determination processing unit 112 differs in the processing of determining the pixels to be thinned out from the pixel set depending on whether the reference pattern is a combination of the same pixels, that is, "00" or "11". Therefore, next, the determination processing unit 112 determines whether or not the reference pattern is a combination of the same pixels (ST304).

When the determination processing unit 112 determines in ST304 that the reference pattern is a combination of the same pixels, it simply thins out one of the pixels of the pixel set. In this case, the determination processing unit 112
Selects the first pixel of the pixel set as the effective pixel and the subsequent pixels as the thinning target pixels (ST305).

Then, the judgment processing section 112 judges whether or not the reduction processing is completed for all the pixels included in one line (ST306), and if the processing is completed, the one line reduction processing is ended. On the other hand, the determination processing unit 112 determines ST30.
If the thinning process is not completed for all the pixels included in one line in 6, the process pixel is advanced by two pixels, and the process of reducing the remaining pixels included in one line is performed (ST307).

On the other hand, when the determination processing unit 112 determines in ST304 that the reference pattern is not a combination of the same pixels, the determination processing unit 112 determines whether the reference pattern of the different pixel is the reference pattern of the different pixel first appearing in the line currently being processed. In order to do so, it is determined whether or not the reference pattern of the different pixel that appears this time is stored in the pattern holding unit 113 (S
T308). Here, in the case of the reference pattern of the different pixel that first appears in the line currently being processed,
The pattern held in the pattern holding unit 113 is “0.
Since it is 0 ″, it is always different from the pattern held in the pattern holding unit 113.

In this way, when the initial value consisting of the same combination of pixel values is held in the pattern holding unit 113 at the start of the image reduction processing, when a reference pattern of a different pixel of any combination first appears. However, regardless of the combination, it can be recognized that this reference pattern appears first.

When the judgment processing unit 112 judges in ST308 that the reference pattern of the different pixel appearing in the pattern holding unit 113 is not held, the reference pattern of the different pixel appears first in the line being processed. Therefore, the head pixel is simply set as the effective pixel (ST3
09). Then, the determination processing unit 112 stores the reference pattern of the different pixel that appears this time in the pattern holding unit 113, and also stores the pixels that are not validated in ST309, that is, the thinned pixel values in the pixel holding unit 114 (S).
T310). Then, the determination processing unit 112 is ST306.
Process shifts to.

On the other hand, when the judgment processing unit 112 judges in ST308 that the reference pattern is held in the pattern holding unit 113, it means that the reference pattern of the different pixel appears in the line which is already being processed. In this case, different processing is performed depending on whether or not the reference pattern of the different pixel that appears this time is the same as the reference pattern of the different pixel that appeared last time. Therefore, the determination processing unit 112 determines whether or not the reference pattern of the different pixel that appears this time is the same as the reference pattern of the different pixel that appeared last time (ST311). In this way, when reference pixels of different pixel combinations appear,
By referring to the pattern holding unit 113, it can be easily determined whether the reference pattern of the different pixel that appears this time is the same as the reference pattern of the different pixel that appeared last time.

Then, the judgment processing section 112 determines ST311.
If it is determined that the reference pattern of the different pixel that appears this time is not the same as the reference pattern of the different pixel that appeared last time, the first pixel of the reference pattern of the different pixel that appears this time is set as an effective pixel (ST309). As described above, when the reference pattern of the different pixel that appears this time is different from the reference pattern of the different pixel that appeared last time, the thinned pixel of the reference pattern of the different pixel of this time is set to the top regardless of which type of pixel was thinned last time. When the pixel is used, the black pixel and the white pixel are alternately selected. Then, the determination processing unit 112
Saves the reference pattern of the different pixel that appears this time in the pattern holding unit 113 (updates the reference pattern), and S
Pixels that are not validated in T309, that is, the thinned pixel values are saved in the pixel holding unit 114 (update of saved pixels)
(ST310). Then, the determination processing unit 112, S
The process moves to T306.

On the other hand, when the judgment processing unit 112 judges in ST311 that the reference pattern of the different pixel that appears this time is the same as the reference pattern of the different pixel that appeared last time, the reference pattern of the different pixel that appears this time is changed to the previous pattern. A pixel different from the pixel selected from the reference pattern of the different pixel that appears is selected. That is, the determination processing unit 112 sets the pixels thinned last time from the reference pattern of the different pixels that appeared last time, which are stored in the pixel holding unit 114, as effective pixels (ST3).
12). In this way, when the same reference pattern of different pixels appears consecutively, the pixel held in the pixel holding unit 114 is set as an effective pixel, so that the reference pixel of the different pixel that appears last time appears in the reference pattern of the different pixel that appears this time. Pixels different from the reference pattern can be easily selected. As a result, a pixel of a type different from the previously selected pixel is selected and the reduction processing is performed, so that the balance between the white ratio and the black ratio in the original image can be maintained.
Then, the determination processing unit 112 moves to the processing of ST310.

As described above, the image reduction unit 111 reduces the image data to 1/2.

Next, the image reduction unit 111 displays "11001".
The process of reducing the line consisting of pixels "0101001" by 50% will be described with reference to FIG.
It is a figure for explaining 50% reduction processing of an image reduction part concerning the above-mentioned embodiment.

First, the pattern holding unit 113 is set to "00".
Then, by setting the pixel holding unit 114 to “0”, the stored reference pattern and the stored pixels are cleared (4 in the figure).
01).

Next, the first pixel "1" of "110010101001" and the next pixel "1" are set as the reference pattern. In this case, since the reference pattern is “11” and the combination of the same pixels is used, the determination processing unit 112 regards the leading pixel “1” as an effective pixel. In this case, since the reference pattern is composed of the same pixels, the contents held in the pattern holding unit 113 and the pixel holding unit 114 are not updated (402 in the figure).

Next, the judgment processing section 112 selects the processing pixel as 2 pixels.
By advancing the pixels, 2 bits of "0" and "0" which is the next pixel are used as a reference pattern. In this case, the reference pattern is "0
Since it is "0", and it is composed of the same pixel, the determination processing unit 112 regards the leading pixel "1" as an effective pixel.
In this case, since the reference pattern consists of the same pixels, the contents held in the pattern holding unit 113 and the pixel holding unit 114 are not updated (403 in the figure).

Next, the judgment processing section 112 selects the processing pixel as 2 pixels.
By advancing pixels, 2 bits of "1" and "0" which is the next pixel are used as a reference pattern. In this case, the reference pattern is "1.
Since it is 0 ”, and a combination of different pixels is obtained, the determination processing unit 1
Reference numeral 12 refers to the pattern holding unit 113. in this case,
Since “00” is stored in the pattern holding unit 113, the determination processing unit 112 sets the leading pixel “1” as an effective pixel. Further, in this case, since the reference patterns are composed of pixels different from each other, the reference pattern “10” that appears this time in the pattern storage unit 113 and the pixel storage unit 11 are displayed.
"0" which is the thinned pixel is stored in 4 (40 in the figure).
4).

Next, the judgment processing section 112 selects the processing pixel as 2 pixels.
By advancing pixels, 2 bits of "1" and "0" which is the next pixel are used as a reference pattern. In this case, the reference pattern is "1.
The determination processing unit 112 refers to the pattern holding unit 113 because it is 0 ”and the pixel combination is different. In this case, the determination processing unit 112 stores“ 10 ”in the pattern holding unit 113. Detects a pixel thinned out last time by referring to the pixel holding unit 114 in order to validate a pixel different from the pixel validated last time in this reference pattern. ”
Therefore, the determination processing unit 112 sets the pixel “0” this time as an effective pixel. Further, in this case, since the reference pattern is composed of different pixels, the reference pattern "10" that appears this time in the pattern holding unit 113 and the thinned pixel "1" are stored in the pixel holding unit 114 ( 4 in the figure
05).

Next, the judgment processing section 112 selects the processing pixel as 2
By advancing pixels, 2 bits of "1" and "0" which is the next pixel are used as a reference pattern. In this case, the reference pattern is "1.
The determination processing unit 112 refers to the pattern holding unit 113 because it is 0 ”and the pixel combination is different. In this case, the determination processing unit 112 stores“ 10 ”in the pattern holding unit 113. Detects a pixel thinned out last time by referring to the pixel holding unit 114 in order to validate a pixel different from the pixel validated last time in this reference pattern. ”
Therefore, the determination processing unit 112 sets the pixel “1” this time as the effective pixel. Further, in this case, since the reference patterns are composed of different pixels, the pattern holding unit 113
The reference pattern "10" that appears this time and the thinned pixel "0" are stored in the pixel holding unit 114 (406 in the figure).

Next, the judgment processing unit 112 selects the processing pixel as 2 pixels.
By advancing pixels, 2 bits of "0" and "1" which is the next pixel are used as a reference pattern. In this case, the reference pattern is "0
The determination processing unit 112 refers to the pattern holding unit 113 because it is 1 ”and the pixel combination is different. In this case, since“ 10 ”is stored in the pattern holding unit 113, the determination processing unit 112. Means that the reference pattern consisting of the different pixels that appears this time and the reference pattern consisting of the different pixels that appeared last time are different.
The determination processing unit 112 sets “0”, which is the first pixel in the reference pattern, as an effective pixel. Further, in this case, since the reference patterns are composed of pixels different from each other, the pattern holding unit 1
The reference pattern "01" that appears this time and the thinned pixel "1" are stored in the pixel holding unit 114 (407 in the figure).

In this way, the image reduction unit 111
Original image (line) of "110010101001"
Is reduced by 50% to generate a reduced image (line) of "101010". The point to be noted here is "11
The original picture "0010101001" and "101010"
That is, the black ratio or white ratio does not differ from the reduced image. Further, the difference between the distribution of black pixels in the reduced image and the distribution of black pixels in the original image is very small with respect to the original image. That is, the image is reduced while maintaining the periodicity of the bit pattern of the original image almost completely. In this way, the image reducing unit 111 can reduce the image while maintaining the fidelity to the original image.

Further, the image reducing section 111 converts the image data into 5
Not only 0% reduction but also 50% to 100% reduction is possible. The 50% to 100% reduction processing of the image reduction unit 111 will be described below with reference to FIG. Figure 5
Is 50% to 1 of the image reduction unit according to the above embodiment.
It is an operation | movement flowchart in 00% reduction processing.

When the one-line reduction processing is started, the image reduction unit 111 sets the combination pattern of pixels held in the pattern holding unit 113 to 00 and the thinned pixel value held in the pixel holding unit 114 to 0. , The held combination pattern of pixels and the held thinned pixel value are cleared (ST501). Next, the determination processing unit 112 of the image reduction unit 111 sets the leading pixel of one line as the pixel to be processed (ST502).

Next, the judgment processing section 112 judges whether the processing pixel is a normal reduction judgment target pixel (thinning target pixel) and is a pixel corresponding to the thinning pixel depending on the judgment (ST503). This is because, when the reduction rate is 50%, the thinning processing is performed by referring to 2 bits from the leading pixel, but when the reduction rate is 50% to 100%, there are pixels that are the reduction determination processing target pixels and pixels that are not. . Whether or not the processed pixel is a normal reduction determination target pixel can be determined by the reduction ratio. For example, if the reduction ratio is 80%,
The reduction determination target pixels are arranged every four pixels. That is,
When the reduction ratio is 80%, the reduction determination target pixel is 5
One of the pixels becomes the reduction determination target pixel.

When the determination processing unit 112 determines in ST503 that the processed pixel is not a normal reduction determination target pixel, the processing pixel is not a reduction target pixel.
The processed pixel is set as an effective pixel as it is (ST504).

Then, the judgment processing section 112 judges whether or not the reduction processing has been completed for all the pixels included in one line (ST505). If the processing has been completed, the one-line reduction processing is ended. On the other hand, the determination processing unit 112 determines ST50.
In 5, when the thinning-out process is not completed for all the pixels included in one line, the processed pixel is advanced by one pixel and the process is shifted to the reduction process for the remaining pixels included in one line (ST506).

On the other hand, when the determination processing section 112 determines in ST503 that the processing pixel is a normal reduction determination target pixel, the processing pixel is a reduction determination target pixel. Therefore, the processing pixel set in ST502, Two bits of the next pixel are set as a set, and a combination of pixel values of this set is set as a reference pattern (ST507).

Next, the determination processing unit 112 determines the pixels to be thinned out from the set of pixels depending on whether the reference pattern is a combination of the same pixels, that is, "00" or "11". It is determined whether or not the pattern is a combination of the same pixels (ST508).

When the determination processing section 112 determines in ST508 that the reference pattern is a combination of the same pixels, the determination processing section 112 simply thins out one of the pixels of the pixel set. In this case, the determination processing unit 112
Selects the first pixel of the pixel set as the effective pixel and the subsequent pixels as the thinning target pixels (ST509).

Then, the judgment processing section 112 judges whether or not the reduction processing has been completed for all the pixels included in one line (ST511), and when the processing has been completed, the one-line reduction processing is ended. On the other hand, the determination processing unit 112 determines ST51.
When the thinning-out process is not completed for all the pixels included in one line in 1, the process pixel is advanced by two pixels and the process of reducing the remaining pixels included in one line is performed (ST512).

On the other hand, when the judgment processing section 112 judges in ST508 that the reference pattern is not a combination of the same pixels, the judgment processing section 112 judges whether or not the reference pattern of different pixels first appears in the line currently being processed. It is determined whether or not the reference pattern of this different pixel is already stored in the holding unit 113 (ST513). Further, since the pattern holding unit 113 holds a combination of “00” pixels as an initial value, when a reference pattern of a different pixel appears for the first time, the reference pattern of the appearing different pixel is held in the pattern holding unit 113. The reference pattern is always different.

If the judgment processing unit 112 judges in ST513 that the reference pattern is not held in the pattern holding unit 113, it means that the reference pattern of the different pixel first appears in the line being processed, and therefore, simply. The first pixel is set as an effective pixel (ST514). And
The determination processing unit 112 stores the reference pattern of the different pixel that appears this time in the pattern holding unit 113, and ST51
The pixels that are not validated in 4, ie, the thinned pixel values are stored in the pixel holding unit 114 (ST510). Then, the determination processing unit 112 shifts to the processing of ST511.

On the other hand, when the judgment processing section 112 judges in ST513 that the reference pattern of the reference different pixel is held in the pattern holding section 113, the reference pattern of the different pixel has already appeared in the line being processed. become. In this case, different processing is performed depending on whether or not the reference pattern of the different pixel that appears this time is the same as the reference pattern of the different pixel that appeared last time. Therefore, the determination processing unit 1
12 determines whether the reference pattern of the different pixel that appears this time is the same as the reference pattern of the different pixel that appeared last time (S).
T515).

Then, the judgment processing section 112 proceeds to ST515.
When it is determined that the reference pattern of the different pixel that appears this time is not the same as the reference pattern of the different pixel that appeared last time, the first pixel of the reference pattern that appears this time is set as the effective pixel (ST514). Then, the determination processing unit 112
Saves the reference pattern of the different pixel that appears this time in the pattern holding unit 113 (updates the reference pattern), and S
Pixels that are not validated in T514, that is, the thinned pixel values are saved in the pixel holding unit 114 (update of saved pixels)
(ST510). Then, the determination processing unit 112, S
The processing moves to T511.

On the other hand, when the determination processing section 112 determines in ST515 that the reference pattern of the different pixel that appears this time is the same as the reference pattern of the different pixel that appeared last time, the reference pattern of the different pixel that appears this time is changed to the previous pattern. A pixel different from the pixel selected from the reference pattern of the different pixel that appears is selected. That is, the determination processing unit 112 sets the pixels thinned last time from the reference pattern of different pixels stored in the pixel holding unit 114 as the effective pixels (ST516). Then, the determination processing unit 112 moves to the processing of ST510.

As described above, the image reducing section 111 reduces the pixel by 50% with respect to the pixel to be reduced, which is determined according to the reduction rate.
By performing the same processing as reduction, image data can be reduced from 50% to 1
It can be reduced by 00%.

Next, the image reducing section 111 displays "10010".
A process of reducing the line consisting of pixels 1010010 ”by 80%, that is, reducing one pixel from five pixels to four pixels will be described with reference to FIG.
FIG. 8 is a diagram for explaining 80% reduction processing of the image reduction unit according to the above embodiment.

First, the pattern holding unit 113 is set to "00".
Then, by setting the pixel holding unit 114 to “0”, the stored reference pattern and the stored pixels are cleared (6 in the figure).
01).

Next, it is determined whether "1", which is the first pixel of "100101010010", corresponds to the thinned pixel in the reduction determination. Here, if the reduction process is performed by thinning out either the first pixel or the second pixel from the five pixels, the first pixel “1” corresponds to the thinning pixel. First pixel “1” and next pixel “0”
Is set as the reference pattern. In this case, the determination processing unit 11
In No. 2, since the reference pattern is “10” and the pixel is composed of different pixel combinations, the determination processing unit 112 refers to the pattern holding unit 113. In this case, the pattern holding unit 113
Since “00” is stored in the table, the determination processing unit 11
For 2, the first pixel "1" is the effective pixel. Also,
In this case, since the reference patterns consist of different pixels, the reference pattern "10" that appears this time in the pattern holding unit 113 and the thinned pixel "0" are stored in the pixel holding unit 114 (in the figure). 602).

Next, the judgment processing unit 112 selects the processing pixel as 2 pixels.
The pixel is advanced, and the process proceeds to the processing of the pixel of “0”. Since the pixel of “0” is not the reduction determination target pixel, the determination processing unit 112
Sets the pixel of “0” as it is as an effective pixel. In this case, the reference pattern stored in the pattern holding unit 113 and the pixels stored in the pixel holding unit 114 are not updated (603 in the figure).

Next, the judgment processing unit 112 sets the processing pixel to 1
The pixel advances, and the process shifts to the processing of the pixel of "1". Since the pixel of “1” is not the reduction determination target pixel, the determination processing unit 112
Sets the pixel of “1” as it is as an effective pixel. In this case, the reference pattern stored in the pattern holding unit 113 and the pixels stored in the pixel holding unit 114 are not updated (604 in the figure).

Next, the judgment processing unit 112 sets the processing pixel to 1
The pixel is advanced, and the process proceeds to the processing of the pixel of “0”. Since the pixel of “0” is not the reduction determination target pixel, the determination processing unit 112
Sets the pixel of “0” as it is as an effective pixel. Further, in this case, the reference pattern stored in the pattern holding unit 113 and the pixels stored in the pixel holding unit 114 are not updated (605 in the figure).

Next, the judgment processing unit 112 sets the processing pixel to 1
The pixel advances, and the process shifts to the processing of the pixel of "1". Since the pixel of “1” is the reduction determination target pixel, the determination processing unit 112
Is a reference pattern of 2 bits of "1" pixel and "0" which is the next pixel. In this case, the reference pattern is "1.
The determination processing unit 112 refers to the pattern holding unit 113 because it is 0 ”and the pixel combination is different. In this case, the determination processing unit 112 stores“ 10 ”in the pattern holding unit 113. Detects a pixel thinned out last time by referring to the pixel holding unit 114 in order to validate a pixel different from the pixel validated last time in this reference pattern. ”
Therefore, the determination processing unit 112 sets the pixel “0” this time as an effective pixel. Further, in this case, since the reference patterns are composed of different pixels, the pattern holding unit 113
The reference pattern "10" that appears this time and the thinned pixel "1" are stored in the pixel holding unit 114 (606 in the drawing).

Next, the judgment processing unit 112 sets the processing pixel to 1
The pixel advances, and the process shifts to the processing of the pixel of "1". Since the pixel of “1” is not the reduction determination target pixel, the determination processing unit 112
Sets the pixel of “1” as it is as an effective pixel. In this case, the reference pattern stored in the pattern holding unit 113 and the pixels stored in the pixel holding unit 114 are not updated (607 in the figure).

Next, the judgment processing unit 112 sets the processing pixel to 1
The pixel is advanced, and the process proceeds to the processing of the pixel of “0”. Since the pixel of “0” is not the reduction determination target pixel, the determination processing unit 112
Sets the pixel of “0” as it is as an effective pixel. Further, in this case, the reference pattern stored in the pattern holding unit 113 and the pixels stored in the pixel holding unit 114 are not updated (608 in the figure).

Next, the judgment processing section 112 selects the processing pixel as 2 pixels.
The pixel is advanced, and the process proceeds to the processing of the pixel of “0”. Since the pixel of “0” is not the reduction determination target pixel, the determination processing unit 112
Sets the pixel of “0” as it is as an effective pixel. In this case, the reference pattern stored in the pattern holding unit 113 and the pixels stored in the pixel holding unit 114 are not updated (603 in the figure).

Next, the judgment processing unit 112 sets the processing pixel to 1
The pixel is advanced, and the process proceeds to the processing of the pixel of “0”. Since the pixel of “0” is not the reduction determination target pixel, the determination processing unit 112
Sets the pixel of “0” as it is as an effective pixel. In this case, the reference pattern stored in the pattern holding unit 113 and the pixels stored in the pixel holding unit 114 are not updated (609 in the figure).

Next, the judgment processing unit 112 sets the processing pixel to 1
Pixel advance, let's say to process the pixel of "1". "1"
Is a reduction determination target pixel, the determination processing unit 11
2 is 2 bits of "1" pixel and "0" which is the next pixel
Is a reference pattern. In this case, the reference pattern is "1.
The determination processing unit 112 refers to the pattern holding unit 113 because it is 0 ”and the pixel combination is different. In this case, the determination processing unit 112 stores“ 10 ”in the pattern holding unit 113. Detects a pixel thinned out last time by referring to the pixel holding unit 114 in order to validate a pixel different from the pixel validated last time in this reference pattern. ”
Therefore, the determination processing unit 112 sets the pixel “1” this time as the effective pixel. Further, in this case, since the reference patterns are composed of different pixels, the pattern holding unit 113
The reference pattern "10" that appears this time and the thinned pixel "0" are stored in the pixel holding unit 114 (610 in the drawing).

In this way, the image reduction unit 111
Original image (line) of "100101010010"
Is reduced by 80% to generate a reduced image (line) of "101001001". The point to be noted here is that 50% of the reduction determination target pixel and the next pixel
The point is that the same reduction processing is performed as in the case of reduction. As a result, even when the original image is reduced by 80%, the image can be reduced while maintaining the fidelity to the original image.

As described above, according to the above-described embodiment, when the image stored in the memory is reduced by 50%,
When the reference pattern in which the original pixel of the image is a set of 2 bits in the main scanning direction is referred to and the reference pattern is the same as the reference pattern of the different pixel that appeared last time, the reference pattern of the different pixel that appeared last time is selected. It is possible to select a pixel of a different type from the above-mentioned pixel and reduce it to 1/2. In this way, when reference patterns of different pixels appear consecutively, the pixels of the same type are not thinned out continuously, and black pixels and white pixels are always thinned out alternately. The sex can be maintained almost completely. As a result, 50% reduction can be performed while maintaining the fidelity to the original image.

Further, in the above embodiment, continuous 2 bi
Since the simple process of referring to the pixel of t and determining the thinned pixel based on the combination of consecutive pixels is performed, the image reducing unit 111 can be configured with a simple hardware configuration.

Further, according to the above-described embodiment, when the image stored in the memory is reduced at a reduction rate between 50% and 100%, the reduction determination target pixel (thinning determination target pixel) is determined from this reduction rate. If the reference pattern is the same as the reference pattern of the previously-appearing different pixel, the reference of the previously-appearing different pixel is referred to. A pixel of a different type from the pixel selected from the pattern can be selected and reduced. As a result, when one pixel is thinned out from a combination of two different pixels, black pixels and white pixels are always thinned out alternately in the same reference pattern without continuously thinning out pixels of the same type. It is possible to reduce the size while maintaining it.

Further, according to the above embodiment, when the same reference pattern of different pixels appears consecutively, the pixel held in the pixel holding unit 114 is set as an effective pixel.
A pixel different from the reference pattern of the different pixel that appeared last time can be easily selected as the reference pattern of the different pixel that appears this time. In this way, by selecting a pixel of a type different from the previously selected pixel and performing reduction processing, it is possible to maintain the balance between the white ratio and the black ratio in the original image, so that the fidelity to the original image can be maintained.

Further, according to the above embodiment, when the reference pattern of the different pixel that appears this time is different from the reference pattern of the different pixel that appeared last time, the first pixel of the reference pattern of the different pixel that appears this time can be selected. it can. This allows
If the reference pattern of the different pixel that appeared this time is different from the reference pattern of the different pixel that appeared last time, the thinned pixel of the reference pattern of the current different pixel should be the first pixel regardless of which type of pixel was thinned last time. Thus, the black pixel and the white pixel are alternately selected. As a result, the balance between white ratio and black ratio in the original image can be maintained in the reduced image,
The fidelity to the original picture can be maintained.

In the above embodiment, the image reduction unit 1
11 is composed of simple hardware, the image reduction unit 111
Alternatively, the CPU 101 may perform the image reduction processing of the image reduction unit 111 by using a program as the processing.
Even in this case, the image reduction process can be executed with a simple program.

Further, in the above-described embodiment, in the case of performing memory transmission in which an image is accumulated and then a call is made, the resolution of the facsimile apparatus 100 which is the terminal of the transmission side exceeds the resolution of the terminal of the transmission destination. In this case, the image data is reduced according to the resolution of the destination terminal, but
In addition to reducing the image data used for transmission, the image reducing method of the above embodiment may be used. For example, it may be used when the image data read by the scanner 106 is reduced and printed by the printing device 108 or when reduced and displayed on the display unit.

[0109]

As described above, according to the present invention,
When the image data is reduced, even if reference pixel patterns composed of different pixels appear consecutively, the same pixel is not continuously selected. Therefore, even if the accumulated image is reduced, the reproducibility with respect to the original image can be maintained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a facsimile apparatus according to an embodiment of the present invention.

FIG. 2 is a flow chart of image data transmission processing of the facsimile apparatus according to the above embodiment.

FIG. 3 is an operation flowchart of the image reduction unit according to the above embodiment.

FIG. 4 is a diagram for explaining the 50% reduction processing of the image reduction unit according to the above embodiment.

FIG. 5 is an operation flow chart in the 50% to 100% reduction processing of the image reduction unit according to the above embodiment.

FIG. 6 is a diagram for explaining 80% reduction processing of the image reduction unit according to the above embodiment.

[Explanation of symbols]

100 facsimile machine 101 CPU 103 image memory 104 work memory 105 MODEM 106 scanner 108 printing device 110 CODEC 111 Image reduction unit 112 Judgment processing unit 113 pattern holder 114 pixel holding unit

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5B057 BA01 BA23 CD06 CD07 CD10                       CH11 CH18                 5C076 AA22 BA07 BB06 BB15 CB01                       CB03

Claims (9)

[Claims] 1. When reducing an image stored in a memory by 50%, a reference pattern in which the original pixel of the image is a set of two pixels in the main scanning direction is referred to, and the reference pattern is a combination of the same pixels. When either one of the pixels is selected, and when the reference pattern is a combination of different pixels, either one of the pixels is selected, and then the combination of different pixels is formed, and the combination of the different pixels is the previously-appearing different combination. When the reference pattern that is the same as the combination of pixels appears, the reference of the combination of different pixels that newly appears a pixel of a type different from the selected pixel from the reference pattern of the combination of different pixels that appeared last time Select from the patterns and
Facsimile apparatus equipped with image reducing means for reducing to 2. 2. When the main scanning resolution of the image stored in the memory prior to the calling is twice the main scanning resolution of the other device determined by the communication procedure, the original pixel of the image is set to 2 in the main scanning direction. Referring to a reference pattern having a set of pixels, when the reference pattern is a combination of the same pixels, one of the pixels is selected, while when the reference pattern is a combination of different pixels, one of the pixels is selected. In addition, if the reference pattern consisting of a combination of different pixels and the combination of different pixels is the same as the combination of different pixels that appeared last time, then the reference pattern of the combination of different pixels that appeared last time Facsimile apparatus equipped with an image reducing means for selecting a pixel of a type different from the selected pixel from the reference pattern of the combination of different pixels that has appeared this time and reducing the pixel size to 1/2. 3. From 50% to 1 of the images stored in the memory
When reducing at a reduction ratio of 00%, a thinning pixel to be a thinning determination target is determined from the reduction ratio, and a reference pattern in which two pixels of the thinning pixel and an adjacent pixel are combined is referred to Is a combination of the same pixels, either one of the pixels is selected. On the other hand, when the reference pattern is a combination of different pixels, either one of the pixels is selected, and then the combination of different pixels is selected. When the reference pattern whose combination is the same as the combination of different pixels that appeared last time appears, a pixel of a type different from the selected pixel from the reference pattern of the combination of different pixels that appeared last time appears this time. A facsimile apparatus equipped with an image reducing means for reducing from 50% to 100% by selecting from the reference pattern of a combination of different pixels. 4. When the main scanning resolution of the image stored in the memory prior to making a call is 1 to 2 times the main scanning resolution of the partner machine determined by the communication procedure, the reduction ratio is based on the relationship of the main scanning resolution. Determining a thinning pixel to be a thinning determination target from the reduction ratio, and referring to a reference pattern in which two pixels of the thinning pixel and an adjacent pixel are set, and when the reference pattern is a combination of the same pixels, One of the pixels is selected, and on the other hand, when the reference pattern is a combination of different pixels, either one of the pixels is selected, and then the combination of different pixels is formed, and the combination of the different pixels previously appeared. When the reference pattern that is the same as the combination of No. 1 and No. 2 appears, the different pixel that has newly appeared a pixel of a type different from the selected pixel from the reference pattern of the combination of different pixels that appeared last time. Facsimile apparatus equipped with an image reducing means for reducing from 50% to 100% by selecting from the reference patterns of the combination of. 5. When the reference pattern of the combination of different pixels that appears this time is different from the reference pattern of the combination of different pixels that appeared last time, the image reducing means determines the first pixel of the reference pattern of the combination of different pixels. The facsimile machine according to any one of claims 1 to 4, wherein the facsimile machine is selected. 6. A holding unit that holds a reference pattern of the combination of different pixels that appeared last time, and the image reducing unit refers to the holding unit when the reference pattern of the combination of different pixels appears. 6. The method according to claim 1, wherein it is determined whether the reference pattern of the combination of different pixels that appears this time is the same as the reference pattern of the combination of different pixels that appeared last time. The described facsimile machine. 7. The holding unit holds the reference pattern of the same pixel combination as an initial value, and the image reducing unit refers to the holding unit when a reference pattern of the different pixel combination appears. Then, the reference pattern of the combination of different pixels that appears this time is recognized as the reference pattern of the combination of the different pixels that appears first, and the first pixel of the reference pattern of the combination of the different pixels is selected. The facsimile apparatus according to claim 6. 8. The image reduction apparatus further comprises a pixel holding unit for holding pixels thinned out from a reference pattern of the combination of different pixels that appeared last time, and the image reduction apparatus has previously appeared the reference pattern of the combination of different pixels that appeared this time. The facsimile according to any one of claims 1 to 7, wherein when the combination pattern of the reference patterns of the combination of different pixels is the same, the pixel held in the pixel holding unit is selected as an effective pixel. apparatus. 9. When reducing an image stored in a memory by 50%, a reference pattern in which the original pixel of the image is a set of two pixels in the main scanning direction is referred to, and the reference pattern is a combination of the same pixels. When either one of the pixels is selected, and when the reference pattern is a combination of different pixels, either one of the pixels is selected, and then the combination of different pixels is formed, and the combination of the different pixels is the previously-appearing different combination. When the reference pattern that is the same as the combination of pixels appears, the reference of the combination of different pixels that newly appears a pixel of a type different from the selected pixel from the reference pattern of the combination of different pixels that appeared last time Select from the patterns and
Image reduction method to reduce to 2.