JPH05303633A - Processor for thinning binary picture - Google Patents

Abstract

(57) [Summary] [Purpose] 2 of binary images and halftone pictures including fine lines such as characters.
Provided is a binary image thinning-out processing device in which thin line image portions are not missing or moire fringes are less likely to occur when thinning out a value image. A binarization processing unit 12 binarizes a grayscale image signal input from an image input unit 11 to generate a binary image. The processing target area confirmation unit 16 sequentially sets the processing target area on the binary image according to the thinning rate over the entire image. The thinning-out processing unit 14 determines the type of pixel that represents the inside of the processing target area based on the size relationship between the numbers of black and white pixels within the processing target area and the middle feed flag, and also determines the type of the determined pixel and the inside of the processing target area. The next middle-feed flag is determined from the pixel data of each pixel included in.

Description

Detailed Description of the Invention

[0001]

This invention relates to an image scanner,
The present invention relates to an image processing technique implemented in a facsimile machine, a copying machine, and the like. In particular, the present invention performs a thinning process on a binary image obtained by binarizing an input image to obtain a lower image than an input binary image. The present invention relates to a binary image thinning-out processing device that generates a binary image of resolution.

[0002]

2. Description of the Related Art For example, a conventional image scanner uses an image input section in which a CCD is used as an image pickup element, and an analog amount image signal input from the image input section is converted into a digital signal and then binarized. It has a binarization processing unit that generates a value image and a thinning processing unit that performs a thinning process on the binary image obtained by the binarization processing unit to generate a low-resolution binary image. The processed binary image is output to a display device such as a printer or a CRT of a microcomputer.

40 to 42 show the principle of the thinning process which has been conventionally carried out. In the figure, 1 is a binary image before thinning processing, 2 is a low-resolution binary image after thinning processing, and each rectangular mesh is a binary image 1, 2.
Pixels 3 and 4 forming 2 are shown.

For example, a binary image 1 of 400 dpi is 100
When the thinning process is performed on the binary image 2 of dpi, as shown in FIG. 40, (4 × n) of the binary image 1 (where n = 0,
1,2, ...), which is (4 × m-1)
The pixel data (“1” or “0”) of each pixel 3A located in the column corresponding to (where m = 1, 2, ...) Is converted into a binary image in the image region 5 of 4 rows × 4 columns. It is extracted as representative pixel data, and this is used as the pixel data of the binary image 2 after the thinning process.

In addition, a binary image 1 of 400 dpi is converted to 200 d
When the thinning process is performed on the binary image 2 of pi, as shown in FIG. 41, the row corresponding to (2 × n) of the binary image 1 is located in the column corresponding to (2 × m−1). The pixel data of each pixel 3A to be extracted is extracted as the pixel data representing the binary image in the image area 5 of 2 rows × 2 columns, and this is set as the pixel data of the binary image 2 after the thinning process.

Further, a binary image 1 of 400 dpi is set to 300
When performing the thinning processing on the binary image 2 of dpi, as shown in FIG. 42, (2 × n) and (2 × n +) of the binary image 1 are obtained.
1), pixel data of pixels 3A to 3I located in rows and columns corresponding to (2 × n + 2) are extracted as pixel data forming a binary image in the image region 5 of 4 rows × 4 columns. , And the pixel data of the binary image 2 thinned out into 3 rows × 3 columns.

[0007]

According to the above-described thinning processing, each pixel of the binary image 1 from which pixel data is to be extracted is a pixel at a predetermined position in the image area 5 determined according to the thinning ratio. Therefore, when the binary image 1 is a thin line such as a character, there is a possibility that the thin line may be missing or discontinued from the thinned binary image 2. Further, when the thinning process is performed on the binary image 1 of the halftone dot photograph, there is a problem that moire fringes occur in the binary image 2 after the thinning process due to the periodicity of the thinning process.

The present invention has been made in view of the above problems, and it has been proposed that a binary image including a fine line such as a character or a halftone dot photograph be displayed.
An object of the present invention is to provide a thinning-out processing device for a binary image in which thin lines are omitted and discontinuity and moire fringes are generated when thinning out a value image.

[0009]

According to a first aspect of the present invention, a binary image obtained by binarizing an input image is subjected to a thinning process to obtain a binary image having a lower resolution than the input binary image. A binary image thinning-out processing device for generating an image, wherein processing target area setting means sequentially sets a processing target area over the entire image according to a thinning rate on the binary image, and setting of the processing target area. A binary image in the processing target area is obtained from the size relationship between the number of black pixels and the number of white pixels in the processing target area for each position and the pixel designation information obtained at the set position of the processed processing target area. A representative pixel determination unit that determines a type of a representative pixel and generates each pixel data of a binary image, a type of the pixel determined by the representative pixel determination unit, and a binary image in a processing target region are configured. From the pixel data of each pixel, Designation information determining means for determining pixel designation information for the setting position of the processing target area and outputting it to the representative pixel determining means, and pixel data from the representative pixel determining means to generate a binary image after thinning processing 2 And a value image generating means.

According to a second aspect of the present invention, there is provided the binary image thinning-out processing device according to the first aspect, wherein the processing target area setting means sets the image on the binary image in accordance with the thinning rate. The processing target area along the direction orthogonal to the scanning direction is sequentially set over the entire image.

According to a third aspect of the invention, there is provided the binary image thinning-out processing apparatus according to the first aspect, wherein the designation information determining means is the type of pixel determined by the representative pixel determining means. The pixel designation information for the next set position of the processing target area is determined from the pixel data of each pixel forming the binary image in the processing target area and the pixel designation information obtained at the set position of the processed processing target area. And output to the representative pixel determining means.

According to a fourth aspect of the present invention, a binary image is obtained by performing a thinning process on a binary image obtained by binarizing the input image to generate a binary image having a lower resolution than the input binary image. An image thinning processing device, comprising:
For each pixel forming the value image, a pixel number determination unit that determines the magnitude relationship of the pixel types from the pixel data of the target pixel and the pixel data of the pixels before and after it, and the pixel number of the target pixel from the determination result by the pixel number determination unit And a binary image generating means for correcting the pixel data to generate a binary image.

According to a fifth aspect of the present invention, the binary image thinning processing device according to any one of the first to fourth aspects is applied to an image scanner.

[0014]

The type of pixel representing the inside of the processing target area is determined based on the magnitude relation between the numbers of black and white pixels within the processing target area set on the binary image and the pixel designation information. Claim 1
Alternatively, in the invention of claim 2, the following pixel designation information is determined from the determined pixel type and each pixel data in the processing target region, and in the invention of claim 3, the determined pixel type and processing target are determined. Since the next pixel designation information is determined from each pixel data in the area and the processed pixel designation information, when thinning a binary image including thin lines such as characters or a binary image of a halftone dot photograph. On the other hand, the loss of fine lines and the occurrence of discontinuity and moire fringes are suppressed.

Further, in the thinning processing apparatus according to the second aspect, since the processing target area along the direction orthogonal to the scanning direction of the image is sequentially set over the entire image, a binary image including a thin line such as a character or a halftone photograph can be displayed. When the value image is thinned out, it is possible to prevent the thin lines in the vertical direction from being lost and discontinuous and the moire fringes in the vertical direction from being generated.

According to a fourth aspect of the present invention, in the thinning-out processing apparatus, for each pixel constituting the binary image after the thinning-out process, the size relation of the kind of the pixel is judged from the pixel data of the target pixel and the pixel data of the pixels before and after it, and Since the binary data is generated by correcting the pixel data of the target pixel based on the determination result, it is possible to prevent the horizontal fine lines from being missing and discontinuous and the horizontal moire fringes from being generated.

According to the fifth aspect of the present invention, since the thinning processing apparatus according to the first to fourth aspects is implemented in the image scanner, it is possible to obtain a compressed image in which fine lines are not missing, discontinuity, and moire fringes are small.

[0018]

1 shows an example of the circuit configuration of an image scanner 10 in which the present invention is implemented. The image scanner 10 of the illustrated example includes an image input unit 11, a binarization processing unit 12, a binary image memory 13, a thinning processing unit 14, a setting input unit 15, and a processing target area confirmation unit 16, and the thinning processing unit. 1
The output of No. 4 is connected to the display device 18 via the communication means 17 such as RS-232C.

The image input unit 11 uses CC as an image pickup device.
D is a CCD sensor or the like, which captures the grayscale information of the object and generates a grayscale image signal of an analog amount. The binarization processing unit 12 inputs the grayscale image signal from the image input unit 11, and outputs the grayscale image signal of this analog amount to, for example, 8
After being converted into a bit digital signal, the digital signal is binarized by a predetermined binarization threshold value to generate a binary image. Pixels forming this binary image are composed of pixel data of "1" which represents a white pixel and pixel data of "0" which represents a black pixel. The binary image is stored in the binary image memory 13 in pixel units. Is stored.

The setting input section 15 is for inputting information necessary for setting the processing target area according to the thinning ratio on the binary image. The setting input section 15 is the processing target area confirming section 16 Together with this, the processing target area setting unit 19 is configured. The processing target area confirmation unit 16 is a binary image memory 1
3 for sequentially setting the processing target area at a predetermined position on the binary image read out from the whole image, and processing each pixel data of the binary image read out from the binary image memory 13 It is confirmed whether or not the pixel data is the pixel data of the pixels included in the target area, and the data is output.

The thinning processing section 14 inputs each pixel data of the binary image from the processing target area confirming section 16 and performs thinning processing to generate a binary image having a lower resolution than the input binary image. The binary image after the thinning process is transmitted to the display device 18 via the communication unit 17. Display device 1
Reference numeral 8 denotes a display or printer of a microcomputer, which displays or prints a binary image after the thinning process.

2 to 4 show the principle of the thinning processing by the thinning processing unit 14. In these figures, 21
Is a binary image before thinning processing, 22 is a low-resolution binary image after thinning processing, and each rectangular mesh represents pixels 23 and 24 that form binary images 21 and 22, respectively. ..

For example, the binary image 21 of 400 dpi is converted into 10
When thinning processing is performed on the binary image 22 of 0 dpi,
(4 × n) of the binary image 21 (where n =
0, 1, 2, ...), and a horizontally long processing target area 25 having a size of 4 pixels and extending in the scanning direction of the image is sequentially arranged every 4 pixels from the first pixel over the entire image. The pixel type representing the binary image in the processing target area 25 is determined for each set position, that is, whether the pixel is a white pixel or a black pixel, and if it is a white pixel, pixel data of "1" is set. If it is a black pixel, the pixel data of “0” is used as thinned-out data of the binary image in the image area 26 (4 vertical pixels × 4 horizontal pixels) surrounded by the broken line, and this is used as the thinned-out binary image 22 of the binary image 22. Set to pixel data for one pixel.

In addition, the binary image 21 of 400 dpi is set to 200
When performing the thinning processing on the binary image 22 of dpi, as shown in FIG. 3, the row corresponding to (2 × n) of the binary image 21 has a size of two pixels and is in the scanning direction of the image. Along the entire image, the horizontally long processing target area 25 is sequentially set every two pixels from the first pixel, and the type of pixel representing the binary image in the processing target area 25 is determined for each set position. If there is a pixel data of “1” if there is a black pixel, pixel data of “0” if it is a black pixel, the image area 26 surrounded by a broken line
As the thinned-out data of the binary image in (vertical 2 pixels × horizontal 2 pixels), this is set as the pixel data for one pixel of the binary image 22 after the thinning processing.

Furthermore, the binary image 21 of 400 dpi is set to 30.
When performing the thinning-out process on the binary image 22 of 0 dpi,
, The binary image 21 has (2 × n), (2 × n +
1), for a row corresponding to (2 × n + 2), a horizontally long processing target area 25 having a size of 2 pixels and extending in the scanning direction of the image is sequentially set every 4 pixels from the 3rd pixel over the entire image. , (2 × n) th column and (2 × n + 1)
For each pixel in the column, the pixel data of the binary image 21 is extracted as it is, and the (2 × n + 2) -th column and the (2 × n +)-th column are extracted.
3) For each pixel in the column, the type of pixel that represents the binary image in the processing target area 25 is determined, and the binary image in the image area 26 (4 vertical pixels x 4 horizontal pixels) is shown by a broken line. The thinning data is set to pixel data of vertical 3 pixels × horizontal 3 pixels of the binary image 22 after the thinning processing.

FIG. 5 and FIG. 6 show the procedure of the processing by the processing target area confirmation unit 16 and the thinning processing unit 14 according to the first embodiment from step 1 (indicated by “ST1” in the drawings) to
This is shown in step 20. First, in the initial setting of step 1, the sending flag F as the pixel designation information is "invalid" (F =-
1), the count value N _{W of} white pixels and the count value N of black pixels N
Clear _B and zero to zero.

In the next step 2, it is judged whether or not the processing target area is set by the horizontal synchronizing clock, and in the subsequent step 3, it is judged by the pixel clock whether or not the pixel data is within the processing target area. "YE
S ”, if the input pixel data is a white pixel, the count value N _W of the white pixel is calculated. If the input pixel data is a black pixel, the count value N _W of the black pixel is calculated.
_B is incremented respectively (step 4). If step 2 is "NO", the process proceeds to step 19, and if step 3 is "NO", the process proceeds to step 18.

In the next step 5, it is judged whether or not the counting process has been completed for all the pixels in the processing target area. If the judgment is "NO", the pixel data inputted next is judged. Is performed (step 4), and if “YES”, it is determined in the next step 6 whether or not the count value N _W of white pixels and the count value N _{B of} black pixels match. It is determined whether or not the count value N _{W of} white pixels is larger than the count value N _{B of} black pixels.

If the count values N _W and N _B match,
When the determination in step 6 is "YES", the process proceeds to step 8, and it is determined whether or not the application flag F determined at the previous setting position of the processing target area is "1". If the submission flag F is set to "1", the determination in step 8 is "YES", and the pixel data "1" representing a white pixel is set as the pixel data representing the binary image in the processing target area. Set (step 9).

If the submission flag F is set to "0", the determination at step 8 becomes "NO" and the process proceeds to step 10 where black is used as pixel data representing the binary image in the processing target area. Pixel data "0" representing a pixel is set.

[0031] In step 6, the count value N _B count value N _W and black pixels of a white pixel is determined to mismatch, yet the count value of the white pixel in Step 7 N _W count of black pixels N
_If it is determined that the value is larger than _B , the process proceeds from step 7 to step 9, and pixel data "1" representing a white pixel is set as pixel data representing the binary image in the processing target area. If it is determined in step 7 that the count value N _W of the white pixels is smaller than the count value N _{B of the} black pixels, the process proceeds from step 7 to step 10 and sets the binary image in the processing target area as pixel data representing the binary image. Pixel data "0" representing a black pixel
To set.

In step 11 shown in FIG. 6, it is judged whether or not the set pixel data is pixel data "0" representing a black pixel. If the judgment is "YES", then In step 12, it is determined whether or not white pixels exist in the processing target area based on the count value N _W. If the determination of “N _W = 0” in step 12 is “NO”, the process proceeds to step 13 and the flag F is “1”.
Set. If the determination in step 12 is "YES", the process proceeds to step 16 and the submission flag F is set to "-.
Set to 1 ”.

When it is determined in step 11 that the set pixel data is the pixel data "1" representing the white pixel, the process proceeds from step 11 to step 14,
Whether the black pixel exists in the processing target area is determined by the value of the count value N _B. If step 14 "N _B =
If the determination of "0" is "NO", the process proceeds to step 15 and "0" is set as the delivery flag F. If the determination of step 14 is "YES", the process proceeds to step 16 and the delivery flag. Set "-1" as F.

Next, after the count values T _W and T _B are cleared in step 17, it is determined in step 18 whether or not the processing for one row of the binary image is completed. If this judgment is "NO", the procedure returns to step 3 and the same procedure is executed. If the judgment is "YES", the flag F is reset to "-1" in the next step 19. rear,
In the next step 20, it is determined whether or not the processing has been completed for all the rows. If the determination in step 20 is "N
If “O”, the process returns to step 3 and the same procedure is executed. When the processing for all the rows is completed by repeatedly executing such a procedure, the determination in step 20 becomes “YES”, and the thinning processing of the binary image is completed.

FIGS. 7 to 9 show examples of preventing thin lines in the horizontal direction from being lost. These figures show the processing results of the thinning processing according to the conventional example and the processing results of the thinning processing according to the first embodiment. Are also shown.

FIG. 7 shows a 100 dpi binary image of 400 dpi.
It is a comparative example of the processing result when the thinning processing is performed on the binary image of dpi. In the figure, 23 is a constituent pixel of a binary image before thinning processing, 27 is a constituent pixel of a binary image after thinning processing according to the conventional example, and 24 is a binary image after thinning processing according to the first embodiment. Each of the constituent pixels is shown. Again 2
5A to 25F (indicated by a thick line frame in the figure) indicate the setting position of the processing target area. White circles mean pixel data representing white pixels, and black circles mean pixel data representing black pixels, and the black pixels form an image portion such as a thin line.

In the figure, at the setting position 25A of the first processing target area, the second and third pixels are black pixels. According to the conventional thinning processing, the pixels after the thinning processing become white pixels, whereas according to the thinning processing of the first embodiment, the count value N _W of white pixels and the count value N _{B of} black pixels are Match (“YES” in step 6 of FIG. 5) and the flag F is “−1” (step 8).
Is “NO”), the pixel after the thinning process becomes a black pixel (step 10). In this case, the pixels after the thinning processing are black pixels (“YES” in step 11), and there are white pixels in the processing target area 25A (step 12).
Is "YES"), and the submission flag F is set to "1" (step 13).

At the set position 25B of the second processing target area, only the second pixel is a black pixel, but according to the conventional thinning processing, the pixel after the thinning processing becomes a white pixel, whereas According to the thinning-out process of the first embodiment, the count value N _{W of} white pixels is larger than the count value N _{B of} black pixels (“YES” in step 7), so the pixels after the thinning-out process become white pixels (step 9). ). In this case, the pixel after the thinning process is a white pixel (“NO” in step 11) and there is a black pixel in the processing target area 25B (“YES” in step 14). "0" is set (step 15).

At the set position 25C of the third processing target area, the first and second pixels are black pixels, but according to the conventional thinning processing, the pixels after the thinning processing become white pixels. On the other hand, according to the thinning process of the first embodiment,
Since the count value N _{W of} white pixels and the count value N _{B of} black pixels match (step 6 is “YES”) and the flag F is “0” (step 8 is “NO”), thinning is performed. The processed pixel becomes a black pixel (step 10). In this case, the pixel after the thinning process is a black pixel (step 11
Is "YES"), and since white pixels exist in the processing target area 25C ("YES" in step 12), "1" is set as the report flag F (step 1).
3).

Setting position 25 of the fourth and subsequent processing target areas
Similar processing is performed for D to 25F, and as a result,
In the thinning processing according to the conventional example, the following processing results are white pixels, white pixels, and white pixels, whereas in the thinning processing according to the first embodiment, white pixels, black pixels, and white pixels are obtained.

FIG. 8 shows a binary image of 400 dpi for 200d.
FIG. 9 shows a comparison example of processing results when thinning out a binary image of pi, and FIG. 9 shows a binary image of 400 dpi at 300 dpi.
Comparative examples of the processing results when thinning out the binary image are shown below. In any case, the processing is the same as that in FIG. 7, and here, the processing result of the thinning processing according to the conventional example and the processing result of the thinning processing according to the first embodiment are illustrated, and the detailed description thereof is omitted.

FIGS. 10 to 12 show examples of preventing the occurrence of moire fringes in the lateral direction. In these figures, the processing result of the thinning processing according to the conventional example and the processing result of the thinning processing according to the first embodiment are shown. Are also shown together.

FIG. 10 shows 100 binary images of 400 dpi.
FIG. 11 shows a comparison example of processing results when thinning out a binary image of dpi, FIG. 11 shows a comparison example of processing results when thinning a binary image of 400 dpi into a binary image of 200 dpi, and FIG. Comparative examples of the processing results when the value image is thinned out to a binary image of 300 dpi are shown. In the processing result of the thinning processing according to the conventional example, black pixels or black pixel groups periodically appear and moire fringes are generated. However, in the thinning processing result according to the first embodiment, the generation of black pixels or black pixel groups occurs. There is no periodicity, and moire fringes do not occur. Note that each of the cases of FIGS. 10 to 12 is similar to that of FIG. 7, and the description thereof is omitted.

FIG. 13 shows a circuit configuration example of the thinning processing section 14 based on the principle of FIG. 2 for carrying out the processing procedure of FIGS. 5 and 6. The thinning processing unit 14 in the illustrated example includes a white pixel counter 30, a 1/2 arithmetic unit 31, a comparator 32, a request flag determination unit 33, a request flag buffer 34, a logic circuit 35, a selector 36, and an output unit 37. Including as a configuration. The functions of the respective components will be specifically described below, but the series of operations of the thinning processing unit 14 conforms to the processing procedure of FIGS. 5 and 6, and the description thereof will be omitted.

The white pixel counter 30 inputs the pixel data of each pixel included in the processing target area from the processing target area confirmation unit 16 and counts the number of white pixels in the processing target area.

The processing target area confirmation unit 16 is provided with a horizontal synchronizing clock and a pixel clock, and the number of pixels in the target area (4 pixels in this example), and the binary image memory 13 is obtained by the count value of the horizontal synchronizing clock. It is determined whether the input pixel data is the pixel data of the pixel located in the set row of the processing target area, and whether it is the pixel data of the pixel in the processing target area based on the count value of the pixel clock. To judge.

A pixel clock and the number of pixels in the processing target area are given to the white pixel counter 30, and when the number of pixel clocks corresponding to the number of pixels (4 pixels in this example) is input, the count value T _W is output and reset.

The 1/2 calculator 31 divides the number of pixels in the processing target area by 2 to calculate the reference value S (S = 2 in this example). The comparator 32 compares the count value N _W of the white pixel counter 30 and the reference value S with each other, and N _W > S (N in this example is N
_{If W} = 3 or 4), the first output Out1 is
If N _W = S (when N _W = 2 in this example), the second output Out2 is N _W <S (N _W = 1 or 0 in this example).
In case of), the third output Out3 is "1".
Becomes

The request flag determination unit 33 inputs the count value N _W of the white pixel counter 30 and the thinned output OUT of the output unit 37, and sets the request flag F to "1""0""-1". Decide That is, when the pixel data of the thinned-out output OUT is pixel data “0” representing a black pixel and the count value N _W is N _W ≧ 1, the flag F is set to “1”. Further, the pixel data of the thinned-out output OUT is pixel data “1” representing a white pixel, and the count value N _W is N _W ≦
When it is 3, the flag F is set to "0". Further, the pixel data of the thinned-out output OUT is pixel data “0” representing a black pixel and the count value N _W is N _W = 0, or the pixel data of the thinned-out output OUT is pixel data “1” representing a white pixel. And the count value N _W is N _W = 4, the submission flag F is determined to be “−1”.

The delivery flag buffer 34 is for temporarily storing the delivery flag F determined by the delivery flag determination unit 33. When the storage operation is performed, the delivery flag determination unit 33 stores the delivery flag F. Contents are reset.

The logic circuit 35 outputs a logical output F'of "1" when the delivery flag F stored in the delivery flag buffer 34 is "1", and when it is "0" or "-1". The logical output F ′ of “0” is output to each selector 36. When the second output Out2 is given as a clock from the comparator 32, the selector 36 outputs the logic output F ′ from the logic circuit 35 to the output section 37.

The output section 37 receives the first to third outputs Out1 to Out3 from the comparator 32 and the selector 36.
Logic output F'is given respectively, and the first output Ou
When t1 or the third output Out3 is "1", "1" is output as the thinned output Out, and when the second output Out2 is "1", the value of the logical output F'is output as the thinned output Out.

Note that the thinning processing unit 14 based on the principle of FIGS. 3 and 4 has the same circuit configuration, but the thinning processing unit 14 based on the principle of FIG. It is necessary to have a circuit configuration in which the pixel data of each pixel in the (n) th column and the (2 × n + 1) th column is sent from the processing target region confirmation section 16 to the output section 37.

14 to 16 show the principle of the thinning process of the image scanner according to the second embodiment of the present invention.
The second embodiment is intended to prevent the vertical fine lines from being missing and discontinuous and the vertical moire fringes to occur, and the overall circuit configuration is the same as that of the first embodiment shown in FIG. Illustration is omitted.

In these figures, 21 is a binary image before thinning processing, and 22 is a low-resolution binary image after thinning processing.
Each of the rectangular cells is a binary image 2
Pixels 23 and 24 forming 1 and 22 are shown.

For example, the binary image 21 of 400 dpi is converted into 10
When performing the thinning processing on the binary image 22 of 0 dpi,
As shown in FIG. 4, (4 × n) of the binary image 21 (where n
= 0, 1, 2, ...), a vertically long processing target area 25 having a size of 4 pixels and extending in a direction orthogonal to the scanning direction of the image is sequentially set over the entire image and set. For each position, the type of pixel that represents the binary image in the processing target area 25, that is, whether it is a white pixel or a black pixel, is determined, and if it is a white pixel, the pixel data of "1" is changed to a black pixel. If so, the pixel data of “0” is used as thinned-out data of the binary image in the image area 26 (4 vertical pixels × 4 horizontal pixels) enclosed by the broken line, and this is used as the binary image 22 after the thinning processing.
Is set to the pixel data for one pixel.

In addition, the binary image 21 of 400 dpi is set to 200
In the case of performing the thinning processing on the binary image 22 of dpi, FIG.
As shown in FIG. 5, for a column corresponding to (2 × n) of the binary image 21, a vertically long processing target area 25 having a size of 2 pixels and extending in a direction orthogonal to the scanning direction of the image is provided over the entire image. The regions to be processed 25 are sequentially set, and the processing target area 25
The type of pixel that represents the binary image in the inside is determined. If the pixel is a white pixel, the pixel data of “1”, and if the pixel is a black pixel, the pixel data of “0” is surrounded by a broken line. Pixel data for one pixel of the binary image 22 after the thinning process is set as thinned data of the binary image in (pixel × horizontal two pixels).

Furthermore, the binary image 21 of 400 dpi is set to 30.
When performing the thinning processing on the binary image 22 of 0 dpi,
As shown in FIG. 6, (2 × n) and (2 × n) of the binary image 21.
For columns corresponding to (+1) and (2 × n + 2), a vertically long processing target area having a size of 2 pixels and extending in the direction orthogonal to the scanning direction of the image is set, and the (2 × n) th row and For each pixel in the (2 × n + 1) th row, the pixel data of the binary image 21 is extracted as it is, and for each pixel in the (2 × n + 2) th row and the (2 × n + 3) th row, in the processing target area 25. The types of pixels that represent the binary image are determined, and as the thinned-out data of the binary image in the image area 26 (4 pixels in the vertical direction × 4 pixels in the horizontal direction) indicated by a broken line, the vertical direction of the binary image 22 after the thinning process The pixel data for 3 pixels × 3 pixels in the horizontal direction is set.

17 to 19 show steps 1 to 22 of the processing procedure by the processing target area confirmation unit 16 and the thinning processing unit 14 in the second embodiment. First, in the initial setting of step 1, the flag F is set to "-1" and the count value N _{W of} white pixels and the count value N _{B of} black pixels are cleared to zero.

In the next step 2, it is judged whether or not it is the set column of the processing target area by the pixel clock, and in the following step 3, it is judged by the horizontal synchronization clock whether or not it is the pixel data in the processing target area. The judgment is also "YE
When "S", it is determined whether the input pixel data is pixel data "1" representing a white pixel. If the determination is “YES”, the count value N _W of white pixels is incremented, and if it is a black pixel, the count value N _B of black pixels is incremented, and the count value is assigned to the corresponding column of the predetermined memory. It is stored in the storage area corresponding to (steps 5 and 6). If step 2 is “NO”, go to step 22 and step 3
If is “NO”, the process proceeds to step 21.

In the next step 7, it is judged whether or not the input pixel data is for the last pixel in the processing target area. If the judgment is "NO", then If the determination in step 7 is “YES”, the process proceeds to the pixel processing, and the count value N _W of white pixels and the count value N _{B of} black pixels stored in the storage area of the corresponding column in step 8 And whether the white pixel count value N _W is greater than the black pixel count value N _{B is} determined in subsequent step 9.

If the count values N _W and N _B match,
When the determination in step 8 is "YES", the process proceeds to step 10, and it is determined whether or not the delivery flag F determined at the previous setting position of the processing target area in the same column is "1". The request flag F is also stored in a predetermined memory for each set column of the processing target area. If the request flag F is set to "1", the determination in step 10 is "YES", and the process Pixel data "1" representing a white pixel is set as pixel data representing a binary image in the target area (step 11).

If the sending flag F is set to "0", the determination in step 10 becomes "NO" and the process proceeds to step 12, where black is used as pixel data representing the binary image in the processing target area. Pixel data "0" representing a pixel is set.

[0064] In step 8, the count value N _B count value N _W and black pixels of a white pixel is determined to mismatch, yet the count value of the white pixel in Step 9 N _W count of black pixels N
_If it is determined that it is larger than _B , the process proceeds to step 11 and pixel data "1" representing a white pixel is set as pixel data representing the binary image in the processing target area. If it is determined in step 9 that the count value N _W of white pixels is smaller than the count value N _{B of} black pixels, the process proceeds to step 12 and black pixels are selected as pixel data representing the binary image in the processing target area. The pixel data “0” to be represented is set.

In the next step 13, it is judged whether or not the set position of the processing target area is the final position of the row. If the judgment is "YES", the process proceeds to step 19 and the flag F is set to " -1 "is set.

If the determination in step 13 is "NO", the process proceeds to step 14 and it is determined whether the set pixel data is pixel data "0" representing a black pixel. If the determination is "YES", then step 15
Then, it is determined by the value of the count value N _W whether or not a white pixel exists in the processing target area. If step 15 “N _W
If the determination of "= 0" is "NO", the process proceeds to step 16 and "1" is set as the submission flag F. If the determination in step 12 is "YES", the process proceeds to step 19 and "-1" is set as the submission flag F.

When it is determined in step 14 that the set pixel data is the pixel data "1" representing the white pixel, the process proceeds from step 14 to step 17,
Whether the black pixel exists in the processing target area is determined by the value of the count value N _B. If step 17 "N _B =
If the determination of "0" is "NO", the process proceeds to step 18 and "0" is set as the reporting flag F. If the determination of step 17 is "YES", the process proceeds to step 19 and the reporting flag. Set "-1" as F.

Next, after the count values T _W and T _B are cleared in step 20, it is determined in step 21 whether or not the processing for one line of the binary image is completed. If this determination is "NO", the same procedure is executed by returning to step 3, and if the determination is "YES", it is determined in the next step 22 whether or not the processing has been completed for all rows. judge. If the determination in step 22 is "NO", the process returns to step 2 and the same procedure is executed. When the processing for all the rows is completed by repeatedly executing such a procedure, the determination in step 22 is “YE
S ”, and the thinning processing of the binary image is completed.

It is to be noted that the figures showing the processing results of the thinning-out processing according to the second embodiment, that is, FIGS.
The diagram corresponding to FIG. 12 is similar to that of the first embodiment, and therefore, illustration and description thereof are omitted here.

FIG. 20 shows a circuit configuration example of the thinning processing section 14 based on the principle of FIG. 14 for carrying out the processing procedure of FIGS. The thinning processing unit 14 shown in FIG.
3, a white pixel counter 30, a 1/2 arithmetic unit 31, a comparator 32, an application flag determination unit 33, an application flag buffer 34, and a logic circuit 3.
5, a selector 36, an output unit 37, a count value memory 38, and an application flag memory 39 are provided.

The count value memory 38 has an area for storing the count value N _W of the white pixel counter 30 for each set column of the processing target area. The white pixel counter 30 stores the input pixel data. When the pixel data is “1” representing a white pixel, 1 is added to the count value N _W stored in the storage area corresponding to the set column of the processing target area, and the storage result of the count value memory 38 (total The numerical value N _W ) is updated.

The submission flag memory 39 also has an area for storing the submission flag F for each set column of the processing target area, and the submission flag F corresponding to the set column of the processing target area is submitted. The flag is read from the corresponding storage area of the flag memory 39 and set in the delivery flag buffer 34. The rest of the configuration is similar to that of the first embodiment, and the same description will not be repeated here.

21 and 22 show the thinning-out processing procedure of the image scanner according to the third embodiment of the present invention. The entire circuit configuration of the third embodiment is the same as that of the first embodiment of FIG. The same is true, and illustration is omitted here.

In the figure, step 1 to step 10
Is a procedure for setting pixel data representing a binary image in the processing target area, and is similar to the procedure (steps 1 to 10) shown in FIG. 6 of the first embodiment.

Next, in step 11 of FIG. 22, it is judged whether or not the set pixel data is pixel data "0" representing a black pixel. If the judgment is "YES", then In step 12, it is determined whether or not there are white pixels in the processing target area based on the count value N _W. If the determination of “N _W = 0” in step 12 is “NO”, the process proceeds to step 14 and the flag F is “1”.
Set.

If the determination in step 12 is "YES", the process proceeds to step 13 and it is determined whether the delivery flag F is "1". If the determination is "YES", the process proceeds to step 14 and "1" is set as the submission flag F. If the determination in step 13 is "NO", the process proceeds to step 18 and "-1" is set as the report flag F.

When it is determined in step 11 that the set pixel data is the pixel data "1" representing the white pixel, the process proceeds from step 11 to step 15,
Whether the black pixel exists in the processing target area is determined by the value of the count value N _B. If step 15 "N _B =
If the determination of "0" is "NO", the process proceeds to step 17 and "0" is set as the submission flag F.

If the determination at step 15 is "YES", then at step 16, it is determined whether the application flag F is "0". If the determination is “YES”, the process proceeds to step 17, and “0” is set as the report flag F. If the determination in step 16 is “NO”, the process proceeds to step 18 and the report flag F is set. Set to "-1".

The following Steps 19 to 22 correspond to Steps 17 to 20 in FIG. 6 and will not be described here.

FIGS. 23 to 25 show examples of preventing thin lines in the horizontal direction from being lost. These figures show the processing results of the thinning processing according to the conventional example and the processing results of the thinning processing according to the third embodiment. Are also shown.

FIG. 23 shows a 10-bit binary image of 400 dpi.
It is a comparative example of the processing result when the thinning processing is performed on the binary image of 0 dpi. In the figure, 23 is a constituent pixel of a binary image before thinning processing, 27 is a constituent pixel of a binary image after thinning processing according to the conventional example, and 24 is a binary image after thinning processing according to the second embodiment. Each of the constituent pixels is shown. Further, 25A to 25F (indicated by a thick line frame in the figure) indicate the setting position of the processing target area. White circles mean pixel data representing white pixels, and black circles mean pixel data representing black pixels, and the black pixels form an image portion such as a thin line.

In the figure, at the setting position 25A of the first processing target area, the second and third pixels are black pixels. According to the conventional thinning processing, the pixels after the thinning processing become white pixels, whereas according to the thinning processing of the third embodiment, the count value N _W of white pixels and the count value N _{B of} black pixels are Match (“YES” in step 6 of FIG. 21),
Moreover, since the sending flag F is "-1"("NO" in step 8), the pixels after the thinning process become black pixels (step 10). In this case, the pixels after the thinning-out process are black pixels (“YES” in step 11) and there are white pixels in the processing target area 25A (“NO” in step 12). "1" is set (step 14).

At the set position 25B of the second processing target area, only the second pixel is a black pixel, but according to the conventional thinning processing, the pixel after the thinning processing becomes a white pixel, whereas According to the thinning-out process of the third embodiment, the count value N _{W of} white pixels is larger than the count value N _{B of} black pixels (step 7 is “YES”), so the pixels after the thinning-out process become white pixels (step 9). In this case, the pixel after the thinning process is a white pixel (“NO” in step 11) and there are black pixels in the processing target area 25B (“NO” in step 14). "0"
Are set (step 17).

If the second processing target area setting position 2
5B, assuming that all the processing target areas are black pixels, the count value N _W of the white pixels is smaller than the count value N _{B of the} black pixels (step 7 is “NO”), and thus the pixels after the thinning processing are It becomes a black pixel (step 10). In this case, the pixel after the thinning process is a black pixel (“YES” in step 11), there is no white pixel in the processing target area 25B (“YES” in step 12), and the flag F is set. Since it is "1" (step 13 is "YES"),
"1" is set as the report flag F (step 14). In this case, if the report flag F is "0" (step 13 is "NO"), "-1" is set as the report flag F (step 18).

If it is assumed that the processing target area is entirely white pixels, the count value N _{W of} white pixels is larger than the count value N _{B of} black pixels (step 7 is “YES”).
The pixels after the thinning process become white pixels (step 9). In this case, the pixel after the thinning process is a white pixel (“NO” in step 11), there is no black pixel in the processing target area 25B (“YES” in step 15), and the application flag F is set. Since it is "1" (step 16 is "N"
O "), and" -1 "is set as the report flag F (step 18). In this case, if the delivery flag F is "0" (step 16 is "YES"), "0" is set as the delivery flag F (step 1).
7).

Setting position 25 of the third and subsequent processing target areas
Similar processing is performed for C to 25F, and as a result,
In the thinning processing according to the conventional example, the following processing results are white pixels, white pixels, white pixels, and white pixels.
In the thinning processing according to the embodiment, black pixels, white pixels, black pixels, and white pixels are obtained.

FIG. 24 shows 200 binary images of 400 dpi.
FIG. 25 shows a comparative example of processing results when thinning out a binary image of dpi of 300 dpi, and FIG.
An example of comparison of processing results when thinning out a binary image of i
Shown respectively. In any case, the processing is the same as that in FIG. 23, and here, the processing result of the thinning processing according to the conventional example and the processing result of the thinning processing according to the third embodiment are illustrated, and the detailed description thereof will be omitted.

26 to 28 show examples of preventing the generation of moire fringes in the lateral direction. These figures show the processing result of the thinning processing according to the conventional example and the processing result of the thinning processing according to the third embodiment. Are also shown.

FIG. 26 shows 100 binary images of 400 dpi.
27 shows a comparative example of processing results when thinning out a binary image of dpi, FIG. 27 shows a comparative example of processing results when thinning a binary image of 400 dpi into a binary image of 200 dpi, and FIG. Comparative examples of the processing results when the value image is thinned out to a binary image of 300 dpi are shown. In the processing result of the thinning processing according to the conventional example, black pixels or black pixel groups appear periodically and moire fringes are generated. However, in the thinning processing result according to the third embodiment, black pixels or black pixel groups are generated. There is no periodicity, and moire fringes do not occur. Note that each of the cases of FIGS. 26 to 28 is similar to that of FIG. 23, and the description thereof is omitted.

FIG. 29 is a thinning-out processing unit 14 based on the principle of FIG. 2 for carrying out the processing procedure of FIGS. 22 and 23.
An example of the circuit configuration of is shown. The thinning-out processing unit 14 in the illustrated example has the same configuration as that of the first embodiment shown in FIG. 13, that is, a white pixel counter 30, a 1/2 calculator 31, a comparator 32,
Request flag determination unit 33, request flag buffer 34,
It includes a logic circuit 35, a selector 36, and an output section 37.

In the third embodiment, the application flag determining unit 33 outputs the thinned-out output OUT from the output unit 37, the count value N _W of the white pixel counter 30, and the previous application flag held in the application flag buffer 34. Enter the flag F and
This is different from the first embodiment in that the report flag F is determined from these. The rest of the configuration is similar to that of the first embodiment, and the same description will not be repeated here.

FIG. 30 shows a circuit configuration example of the image scanner 10 according to the fourth embodiment of the present invention. The image scanner 10 of the illustrated example includes an image input unit 11 and a binarization processing unit 1.
It includes a binary image memory 13, a thinning-out processing unit 50, a setting input unit 51, and a majority voting correction unit 52, and the output of the majority voting correction unit 52 is sent to a display device 18 via a communication means 17 such as RS-232C. It is connected.

The image input section 11, the binarization processing section 12 and the binary image memory 13 are the same as those in the first embodiment of FIG. 1 and their explanations are omitted. The thinning-out processing unit 50 executes the thinning-out process based on the conventional thinning-out principle shown in FIGS. 40 to 42, and for example 400d based on the information related to the thinning-out ratio input from the setting input unit 51.
The binary image of pi is 100 dpi, the binary image of 400 dpi is 200 dpi, and the binary image of 400 dpi is 30 dpi.
A low-resolution binary image thinned out at 0 dpi is generated.

As shown in FIG. 32, the majority decision correcting unit 52, for each pixel forming the binary image after the thinning processing, pixel data of the target pixel 41 (pixel data "1" representing a white pixel in the illustrated example). ) And the pixel data of each of the pixels 42 and 43 before and after that (in the illustrated example, the pixel data "0" represents the black pixel for the pixel 42 and the pixel data "1" represents the white pixel for the pixel 43). The magnitude relationship with the number of pixels is determined, and the pixel data of the target pixel 41 is corrected from the determination result to generate a binary image.

2 corrected by the majority corrector 52
The value image is transmitted to the display device 18 via the communication means 17. The display device 18 is a display or printer of a microcomputer, and displays or prints the binary image.

FIG. 31 shows the procedure of processing by the majority decision correction section 52 in steps 1 to 7. First, in step 1, the binary image after the thinning process is input, and it is determined whether or not the target pixel is the first pixel of each horizontal line. If the target pixel is now the first pixel, step 1
Is YES, the process proceeds to step 2, and the pixel data of the target pixel is output as it is as the pixel data after the majority correction.

Next, when the target pixel is the second pixel, the determination in step 1 is "NO", so the process proceeds to step 3 and the pixel data of the target pixel and the pixel data of the preceding and following pixels are counted. The number of white pixels is counted as.

In the next step 4, the count value n _W is 2
It is determined whether or not the above is true. If the determination is "YES", the pixel data of the target pixel is set to the pixel data "1" representing the white pixel (step 5). If the determination in step 4 is "NO", the pixel data of the target image is set to pixel data "0" representing a black pixel (step 6).

In the next step 7, it is judged whether or not the processing for all the pixels is completed, and the judgment is "N".
If it is "O", the process returns to step 1 and the same counting process and majority decision are performed for the next target pixel. The same procedure is executed for all the pixels forming the binary image, and when the determination in step 7 is “YES”, the majority correction process is completed.

FIGS. 33 to 35 show examples of preventing the interruption of thin lines in the horizontal direction. These figures show the processing results of the thinning processing according to the conventional example and the thinning processing according to the fourth embodiment for performing the majority correction. The processing result of is also shown.

In FIG. 33, a binary image of 400 dpi is converted into 10
It is a processing result when a thinning process is performed on a binary image of 0 dpi. In the figure, 23 is a constituent pixel of a binary image before thinning processing, 27 is a constituent pixel of a binary image after thinning processing according to a conventional example that does not perform majority correction, and 24 is a fourth embodiment that performs majority correction. Each of the constituent pixels of the binary image after the thinning processing by is shown.

White circles represent pixel data representing white pixels, and black circles represent pixel data representing black pixels.
In the binary image after the thinning processing according to the conventional example, the discontinuous portion T
On the other hand, such a discontinuity does not exist in the binary image after the thinning processing according to the fourth embodiment.

In the figure, the pixel data of the (4n + 1) th (where n = 0, 1, 2, ...) Pixel data of the binary image before thinning processing is extracted to obtain pixel data after thinning processing (conventional example). It corresponds to the thinning processing result by). Therefore, since the first pixel is a white pixel, the pixel after the thinning process is a white pixel, the fifth pixel is a black pixel, the pixel after the thinning process is a black pixel, and so on. Pixels, white pixels, black pixels, black pixels follow.

Since the first pixel after the thinning-out process is a white pixel, the pixel after the majority correction is a white pixel as it is. If the next pixel is the target pixel for majority correction, the target pixel is a black pixel, the immediately preceding pixel (first) is a white pixel, and the immediately following pixel (third) is a black pixel. The number of white pixels becomes smaller than 2, and the pixels after the majority correction become black pixels. From the same principle, the following target pixels are all set to black pixels after the majority correction.

FIG. 34 shows a 200-value binary image of 400 dpi.
FIG. 35 shows the processing result when the binary image of dpi is thinned, and FIG. 35 shows the processing result when the binary image of 400 dpi is thinned to the binary image of 300 dpi. In any case, it is similar to that of FIG. 33, and detailed description thereof is omitted here.

FIGS. 36 to 38 show an example of preventing the generation of moire fringes in the lateral direction. In these figures, the processing results of the thinning processing according to the conventional example and the thinning processing according to the fourth embodiment (majority decision correction) are shown. And the processing result of the thinning processing).

FIG. 36 shows 100 binary images of 400 dpi.
FIG. 3 shows the processing result when thinning out a binary image of dpi.
7 shows the processing result when a binary image of 400 dpi is thinned out to a binary image of 200 dpi, and FIG.
The processing results when a binary image of pi is thinned into a binary image of 300 dpi are shown respectively. In the processing result of the thinning processing according to the conventional example, black pixels or a group of black pixels periodically appear and moire fringes are generated. In the thinning-out processing result according to the third embodiment, the black pixels or the black pixel groups have no periodicity, and moire fringes do not occur.

FIG. 39 shows a circuit configuration example of the majority correction unit 52 for carrying out the processing procedure of FIG. The majority correction unit 52 in the illustrated example includes a white pixel counter 53, a comparator 54, and a binary image generation unit 55. The binary image generation unit 55 includes a pixel determination unit 56 and two inversion circuits 57. , 5
9, 2 OR circuits 58, 62, 2 gate circuits 6
Including 0,61.

The white pixel counter 53 is supplied with the pixel clock, the horizontal synchronizing clock, and the number of pixels to be counted (3 in this case).
The binary image after the thinning process is input, and the number of white pixels is counted from the pixel data of each target pixel and each pixel data of the pixels before and after it.

The comparator 54 compares the count value n _W of the white pixel counter 53 with the reference value “2” of the majority decision, and n
_{If W} ≧ 2, the first output Out1 is “1”, and if n _W <2, the second output Out2 is “1”.

The first output Out1 of the comparator 54 is given as one input of the OR circuit 58, the second output Out2 is given as the other input of the OR circuit 58 via the inverting circuit 57, and the output of this OR circuit 58 is given. Is one gate circuit 6
Given to 1.

The pixel discriminating unit 56 inputs the binary image after the thinning process, and outputs "1" as the discrimination output when the target pixel corresponds to the first pixel of each horizontal line. This discrimination output is given to the inverting circuit 59, and the inverting output opens and closes the gate circuit 61.

The other gate circuit 60 includes a thinning processing unit 5
The binary image after the thinning process is input from 0, and the gate circuit 60 is opened / closed by the discrimination output of the pixel discrimination unit 56. The gate circuit 60 allows only the pixel data of the first pixel of each horizontal line to pass as it is, and the gate circuit 61 allows the pixel data after the majority correction for the pixels other than the first pixel of each horizontal line to pass. The pixel data are combined by the OR circuit 62 and output as pixel data after the majority correction.

Although each of the above-described embodiments shows an example in which the present invention is applied to an image scanner, the present invention is not limited to the image scanner and can be applied to a facsimile or a copying machine.

[0115]

As described above, according to the present invention, the type of pixel representing the inside of the processing target area is determined based on the size relationship between the number of black and white pixels in the processing target area set on the binary image and the pixel designation information. In the invention of claim 1, the pixel designation information is determined from the determined type of pixel and the pixel data of each pixel included in the processing target region. In the invention of claim 3, the pixel designation information is determined. Since the pixel designation information is determined from the type of the pixel and the pixel data of each pixel included in the processing target area and the processed pixel designation information, a thin line such as a character is included.
When thinning out a binary image such as a value image or a halftone dot photograph, it is possible to prevent the image portion of the thin line from being missing, discontinuity, and moire fringes.

In the thinning processing apparatus according to the second aspect, since the processing target area along the direction orthogonal to the scanning direction of the image is sequentially set over the entire image, the binary image including the thin line such as a character or the halftone photograph is displayed. When thinning out the value image, it is possible to prevent the occurrence of fine lines in the vertical direction and breaks and the generation of moire fringes in the horizontal direction.

Further, in the thinning-out processing device according to the fourth aspect, for each pixel forming the binary image after the thinning-out process, the size relation of the kind of pixel is judged from the pixel data of the target pixel and the pixel data of the pixels before and after it. Since the pixel data of the target pixel is corrected based on the determination result to generate a binary image, it is possible to similarly prevent the thin line from being missing, discontinuity, and moire fringes.

Further, according to the invention of claim 5, since the thinning processing device is implemented in the image scanner, there is a remarkable effect that a compressed image in which thin lines are not missing, discontinuity and moire fringes are few can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an image scanner embodying the present invention.

FIG. 2 is an explanatory diagram showing a principle of thinning processing by a thinning processing unit.

FIG. 3 is an explanatory diagram showing a principle of thinning processing by a thinning processing unit.

FIG. 4 is an explanatory diagram showing the principle of thinning processing by a thinning processing unit.

FIG. 5 is a flowchart showing a procedure of processing by a processing target area confirmation unit and a thinning processing unit in the first embodiment.

FIG. 6 is a flowchart showing a procedure of processing by a processing target area confirmation unit and a thinning processing unit in the first embodiment.

FIG. 7 is an explanatory diagram showing an example of preventing loss of thin lines according to the first embodiment.

FIG. 8 is an explanatory diagram showing an example of preventing thin line loss according to the first embodiment.

FIG. 9 is an explanatory diagram showing an example of preventing loss of fine lines according to the first embodiment.

FIG. 10 is an explanatory diagram showing an example of preventing the generation of moire fringes according to the first embodiment.

FIG. 11 is an explanatory diagram showing an example of preventing the generation of moire fringes according to the first embodiment.

FIG. 12 is an explanatory diagram showing an example of preventing the generation of moire fringes according to the first embodiment.

FIG. 13 is a block diagram showing a circuit configuration example of a thinning-out processing unit in the first embodiment.

FIG. 14 is an explanatory diagram showing the principle of thinning processing according to the second embodiment of the present invention.

FIG. 15 is an explanatory diagram showing the principle of thinning processing according to the second embodiment of the present invention.

FIG. 16 is an explanatory diagram showing the principle of thinning processing according to the second embodiment of the present invention.

FIG. 17 is a flowchart showing a procedure of processing by a processing target area confirmation unit and a thinning processing unit in the second embodiment.

FIG. 18 is a flowchart showing a procedure of processing by a processing target area confirmation unit and a thinning processing unit in the second embodiment.

FIG. 19 is a flowchart showing a procedure of processing by a processing target area confirmation unit and a thinning processing unit in the second embodiment.

FIG. 20 is a block diagram showing a circuit configuration example of a thinning-out processing unit in the second embodiment.

FIG. 21 is a flowchart showing a thinning-out processing procedure in the third embodiment of the present invention.

FIG. 22 is a flowchart showing a thinning-out processing procedure in the third embodiment of the present invention.

FIG. 23 is an explanatory diagram showing an example of preventing thin line loss according to the third embodiment.

FIG. 24 is an explanatory diagram showing an example of preventing thin line loss according to the third embodiment.

FIG. 25 is an explanatory diagram showing an example of preventing thin line loss according to the third embodiment.

FIG. 26 is an explanatory diagram showing an example of preventing the generation of moire fringes according to the third embodiment.

FIG. 27 is an explanatory diagram showing an example of preventing the generation of moire fringes according to the third embodiment.

FIG. 28 is an explanatory diagram showing an example of preventing the generation of moire fringes according to the third embodiment.

FIG. 29 is a block diagram showing a circuit configuration example of a thinning-out processing unit in the third embodiment.

FIG. 30 is a block diagram showing a circuit configuration of an image scanner according to a fourth embodiment of the present invention.

FIG. 31 is a flowchart showing a processing procedure of majority voting correction processing in the fourth embodiment.

FIG. 32 is an explanatory diagram showing the principle of majority voting correction in the fourth embodiment.

FIG. 33 is an explanatory diagram showing an example of preventing thin line loss in the fourth embodiment.

FIG. 34 is an explanatory diagram showing an example of preventing thin line loss in the fourth embodiment.

FIG. 35 is an explanatory diagram showing an example of preventing thin line loss in the fourth embodiment.

FIG. 36 is an explanatory diagram showing an example of preventing the generation of moire fringes according to the fourth embodiment.

FIG. 37 is an explanatory diagram showing an example of preventing the generation of moire fringes according to the fourth embodiment.

FIG. 38 is an explanatory diagram showing an example of preventing the generation of moire fringes according to the fourth embodiment.

FIG. 39 is a block diagram illustrating a circuit configuration example of a majority decision correction unit in the fourth embodiment.

FIG. 40 is an explanatory diagram showing the principle of conventional thinning processing.

FIG. 41 is an explanatory diagram showing the principle of conventional thinning processing.

FIG. 42 is an explanatory diagram showing the principle of conventional thinning processing.

[Explanation of symbols]

 Reference Signs List 10 image scanner 11 image input unit 12 binarization processing unit 14, 50 thinning processing unit 16 processing target area confirmation unit 19 processing target area setting unit 52 majority decision correction unit 53 white pixel counter 54 comparator 55 binary image generation unit

Claims (5)

[Claims] 1. A binary image thinning processing device for thinning a binary image obtained by binarizing an input image to generate a binary image having a lower resolution than the input binary image. And a processing target area setting unit that sequentially sets the processing target area over the entire image according to the thinning ratio on the binary image, and the number of black pixels in the processing target area for each setting position of the processing target area. And the number of white pixels and the pixel designation information obtained at the set position of the processed region to be processed, the type of pixel representing the binary image in the processed region is determined to determine the binary image. Representative pixel determining means for generating each pixel data of, and the type of pixel determined by the representative pixel determining means,
Designation information determining means for determining pixel designation information for the next set position of the processing target area from pixel data of each pixel forming a binary image in the processing target area and outputting the pixel designation information to the representative pixel determining means; A binary image thinning processing device, comprising: a binary image generating means for inputting pixel data from the determining means to generate a binary image after thinning processing. 2. The processing target area setting means sequentially sets the processing target area along the direction orthogonal to the scanning direction of the image over the entire image according to the thinning rate on the binary image. The binary image thinning processing device described in 1. 3. The designation information determining means, the type of pixel determined by the representative pixel determining means, the pixel data of each pixel forming a binary image in the processing target area, and the processed processing target area. The binary image thinning-out according to claim 1, wherein the pixel designation information for the next set position of the processing target area is determined from the pixel designation information obtained at Processing equipment. 4. A binary image thinning processing device for thinning a binary image obtained by binarizing an input image to generate a binary image having a lower resolution than the input binary image. A pixel number determining unit that determines a magnitude relationship between pixel types from pixel data of a target pixel and pixel data of pixels before and after the pixel of the binary image after the thinning processing; A binary image thinning processing device comprising: a binary image generating unit that corrects pixel data of a target pixel from a determination result of the determining unit to generate a binary image. 5. The binary image thinning processing device according to claim 1, wherein the binary image thinning processing device is implemented in an image scanner.