JP2009212823A - Image processing apparatus, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently reduce an image without generating lack of information. <P>SOLUTION: A reduction part 160 of this image processing apparatus 10 reduces an original image acquired via an image input part 12 by a factor of f. A magnification part 162 increases a reduction result image obtained by the reduction part 160 by a factor of f. An NG area discrimination part 1640 of a reduced NG mask creation part 164 discriminates an NG area where the lack of information is generated by reduction processing by comparing the original image with a magnification result image obtained by the magnification part 162. A reduced NG mask correction part 1642 corrects the NG area, and creates a corrected reduced NG mask including the NG area after correction. A deformation reduction part 166 deforms and reduces the original image using different reduction ratios for the NG area in the corrected reduced NG mask and areas except the NG area. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image processing apparatus and a program.

  In the binary image reduction conversion process, information may be lost before and after the conversion. For example, a thin line in the original image before the reduction conversion may disappear in the image after the reduction conversion. Further, for example, a thin line of the background color in the original image disappears in the converted image, so that a plurality of different lines or regions in the original image may be represented as one line or region in the converted image. . When such information loss occurs in the reduction conversion process, the image quality deteriorates.

  As a conventional technique for preventing the occurrence of information loss in image reduction conversion processing, for example, Patent Document 1 evaluates the characteristics of black pixel distribution in binary image data, and based on this evaluation result, An apparatus for reducing and converting binary image data by preferentially eliminating regions with low distribution is disclosed.

  Patent Document 2 discloses an image data reduction apparatus that divides an image including a plurality of pixels into unit image areas and executes image reduction processing in which each unit image area is one pixel of a reduced image. . In this image data reduction device, when it is detected that a pixel array arranged in a straight line exists in the unit image area, the color information of the pixel array is emphasized, and the reduced image corresponding to the unit image area is displayed. Determine the pixel color of the image.

  Further, for example, in the reduction conversion device disclosed in Patent Document 3, each of the pixels (conversion pixels) in the conversion image is mapped to the original image, and the original image arranged within a certain range around each conversion pixel. By detecting the inversion of the pixel value for the pixel, the presence or absence of a thin line having a width of one pixel within the range of the original image is detected. If a thin line is detected, the pixel value representing the color of the detected thin line is used as the value of the converted pixel, and the thin line is stored. If no thin line is detected, the pixel of the original image closest to the converted pixel Is the value of the conversion pixel.

JP 08-214150 A Japanese Patent Laid-Open No. 2001-100729 JP 05-041795 A

  An object of the present invention is to provide a technique capable of efficiently reducing an image while preventing information loss due to image reduction processing.

  The invention according to claim 1 is a reduction unit that reduces an original image at a predetermined reduction rate, information acquired based on an image obtained as a result of reduction by the reduction unit, and information acquired based on the original image , Comparing the image quality degradation area determination unit for determining an image quality degradation area that is an area in the original image corresponding to an area where image quality degradation occurs in the reduction result image, the image quality degradation area, and the image quality An image processing apparatus comprising: a deformation / reduction unit that reduces the original image by using different reduction ratios for the other areas in the original image other than the deteriorated area.

  According to a second aspect of the present invention, in the first aspect of the present invention, the image processing apparatus further includes an enlargement unit that enlarges the reduction result image using an inverse of the predetermined reduction rate used by the reduction unit as an enlargement rate. The degradation area determination unit includes a value of each pixel included in the image of the enlargement result by the enlargement unit, and a value of a pixel arranged at a position in the original image corresponding to the position of the pixel in the enlargement result image. , And the image quality degradation region is determined.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the deformation / reduction unit does not reduce the image quality deterioration area, and does not reduce the image quality deterioration area other than the area in the original image. Reduction is performed at the predetermined reduction ratio used by the reduction unit.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the region is corrected based on a position in the original image of the region determined by the image quality degradation region determination unit. An image quality deterioration area correction unit that uses a later area as the image quality deterioration area is further provided.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein after performing processing of each unit included in the image processing apparatus with one scanning direction of the original image as a processing direction, Processing of each unit included in the image processing apparatus is performed with a direction perpendicular to the scanning direction as a processing direction.

  The invention according to claim 6 is the invention according to claim 5, wherein the image quality degradation area is a rectangular area having sides parallel to the processing direction from other areas in the original image. A margin adjustment which detects a margin which is an area including only pixels representing a background color and instructs the deformation reduction unit to reduce the detected margin to a size smaller than the size when reduced at the predetermined reduction rate. The deformation reduction unit further reduces the original image in accordance with an instruction from the margin adjustment unit.

  The invention according to claim 7 is the invention according to claim 6, wherein the size of the image after reduction by the deformation reduction unit is obtained, and when the obtained size is larger than the size of the reduction result image, For the original image, processing of at least the reduction unit, the image quality degradation area determination unit, and the margin adjustment unit is executed using a reduction rate different from the predetermined reduction rate used by the reduction unit.

  The invention according to claim 8 is the invention according to any one of claims 1 to 4, wherein the size of the image after reduction by the deformation reduction unit is obtained, and the obtained size is the size of the reduction result image. If the image quality degradation area is larger than the original image, each of the image quality degradation areas is used as an original image, and at least processing of the reduction section and the image quality degradation area determination section is performed using a reduction ratio different from the predetermined reduction ratio used by the reduction section. Execute.

  The invention according to claim 9 is the invention according to any one of claims 1 to 4, wherein at least the reduction unit and the image quality using a plurality of different reduction ratios with an image designated as a processing target as an original image. Of the reduction ratios used in the reduction unit when the image quality deterioration region determination unit determines that the image quality deterioration region does not exist by repeatedly executing the processing of the deterioration region determination unit, the size of the image after reduction And a possible reduction ratio determining unit that determines a reduction ratio that minimizes as a possible reduction ratio of the designated image.

  The invention according to claim 10 is the invention according to claim 9, wherein each of the image quality degradation regions is designated as a processing target and the processing of the possible reduction ratio determining unit is executed, and the deformation reduction unit is configured to perform the image quality degradation. The image quality degradation region is reduced using the possible reduction rate determined by the possible reduction rate determination unit for each of the regions.

  The invention according to claim 11 is a reduction step of reducing an original image at a predetermined reduction rate, information acquired based on an image obtained as a result of reduction by the reduction step, and information acquired based on the original image , Comparing the image quality degradation area determining step for determining the image quality degradation area that is an area in the original image corresponding to the area where the image quality degradation occurs in the reduced result image, the image quality degradation area, and the image quality A program that causes a computer to execute a deformation and reduction step of reducing the original image by using different reduction ratios for the other areas in the original image other than the deteriorated area.

  According to the invention according to claim 1 or 11, the image quality degradation region can be reliably determined by comparing the information acquired based on the reduction result image and the information acquired based on the original image. And other areas in the original image are reduced at different reduction rates, the original image can be reduced without causing deterioration in image quality.

  According to the second aspect of the present invention, the image quality degradation region can be easily determined.

  According to the third aspect of the present invention, it is possible to perform the deformation / reduction process that ensures that the image quality does not deteriorate.

  According to the fourth aspect of the present invention, the corrected image quality degradation region and other regions in the original image can be reduced at different reduction ratios.

  According to the fifth aspect of the present invention, the processing for reducing the image quality degradation region and other regions in the original image at different reduction ratios can be executed by easy calculation.

  According to the invention of claim 6, by reducing the margin in the image to a smaller size, the size of the image as a result of reducing the image quality degradation region and the other regions in the original image at different reduction ratios can be reduced. can do.

  According to the invention of claim 7, when the size of the image after the deformation reduction process is larger than the size of the image as a result of reducing the entire original image at the predetermined reduction rate, the reduction is different from the predetermined reduction rate. It is possible to repeatedly execute the process of determining the image quality degradation area of the original image using the rate, and as a result, the image closer to the size of the image obtained by reducing the entire original image at a predetermined reduction rate is deformed and reduced. It can be obtained as a result of processing.

  According to the eighth aspect of the present invention, when the size of the image after the deformation reduction process is larger than the size of the image as a result of reducing the entire original image at a predetermined reduction ratio, the entire original image is An image having a size closer to the size of the image obtained as a result of reduction at the reduction rate can be obtained as a result of the deformation reduction processing.

  According to the ninth aspect of the present invention, it is possible to obtain a reduction ratio for reducing the image to be processed to the smallest extent within a range where image quality degradation does not occur.

  According to the tenth aspect of the present invention, the entire original image is reduced by a predetermined size as compared with the case where the image quality deteriorated region is not reduced and the other areas of the original image in the image quality deteriorated region are reduced at a predetermined reduction rate. An image having a size closer to the size of the image obtained as a result of reduction at a rate can be obtained as a result of the deformation reduction processing.

  FIG. 1 is a block diagram illustrating an example of a schematic configuration of an image processing apparatus 10 according to an embodiment of the present invention. The image processing apparatus 10 includes an image input unit 12, a user input unit 14, a processing unit 16, a storage unit 18, and an output unit 20.

  The image input unit 12 receives input of image data to be processed and passes it to the processing unit 16. The image data received by the image input unit 12 is, for example, digital data of a binary image having a value representing either white or black for each pixel. The image input unit 12 receives input of image data from a general digital image generation device such as a scanner, for example. Further, for example, the image input unit 12 may receive input of image data from an information processing apparatus such as a computer connected to the image processing apparatus 10 via a network (not shown) such as the Internet or a LAN (Local Area Network). Good. In the following description, digital image data composed of pixels having numerical values representing colors and the like is simply referred to as “image”.

  The user input unit 14 receives an instruction input from the user and passes it to the processing unit 16. The user input unit 14 may be a general input device such as a keyboard and a mouse.

  The processing unit 16 performs processing on the image received by the image input unit 12. The processing unit 16 includes a reduction unit 160, an enlargement unit 162, a reduction NG mask creation unit 164, and a deformation reduction unit 166.

  The reduction unit performs a process of reducing the original image at a predetermined reduction rate. The reduction unit reduces the original image by, for example, a general reduction method used as an image reduction method.

  The enlargement unit 162 performs a process of enlarging an image (hereinafter, also referred to as “reduction result image”) obtained as a result of reduction by the reduction unit. The enlargement unit 162 uses the reciprocal of the reduction rate used by the reduction unit as the enlargement rate, and enlarges the reduction result image by a method corresponding to the reduction method used by the reduction unit. For example, when the reduction unit reduces the original image by a factor of 1/2, the enlargement unit 162 enlarges the reduction result image by a factor of two. The image resulting from the enlargement by the enlargement unit 162 (hereinafter also referred to as “enlargement result image”) has the same size as the original image before being reduced by the reduction unit.

  The reduced NG mask creation unit 164 creates a reduced NG mask including an NG area representing an area in the original image where information loss may occur due to the reduction process of the reduction unit. The reduced NG mask includes a pixel corresponding to each pixel in the original image. Each pixel in the reduced NG mask has information used in processing of the deformation reduction unit 166 described later. For example, each pixel in the reduced NG mask has an NG mask value that is set to ON when the pixel is included in the NG area and set to OFF when the pixel is not included in the NG area. The reduced NG mask creation unit 164 includes an NG area determination unit 1640 and a reduced NG mask correction unit 1642.

  The NG area determination unit 1640 determines a region where information loss may occur due to the reduction process of the reduction unit. For example, the NG area determination unit 1640 determines, as the NG area, an area in which image quality degradation such as disappearance of thin lines or collapse of lines occurs due to the reduction process. For example, the NG area determination unit 1640 determines the NG area by comparing the value of each pixel of the enlarged result image with the value of each pixel of the original image.

  The reduced NG mask correcting unit 1642 corrects the NG area determined by the NG area determining unit 1640 and generates a corrected reduced NG mask. Details of the correction process performed by the reduced NG mask correction unit 1642 will be described later.

  The deformation reduction unit 166 reduces the original image in accordance with the reduced NG mask created by the reduced NG mask creation unit 164. For example, the deformation reduction unit 166 reduces the original image using different reduction ratios for various regions represented by the reduction NG mask. For example, the deformation / reduction unit 166 reduces the NG area represented by the reduced NG mask at a reduction ratio of 1.0 (that is, does not reduce), and the original image area other than the NG area is a predetermined area used by the reduction unit. Reduce at the reduction rate.

  The storage unit 18 is a storage device that stores information necessary for processing in the processing unit 16. For example, the storage unit 18 stores an image to be processed by the processing unit 16, values of variables used in processing performed by the processing unit 16, a program describing a procedure of processing performed by the processing unit 16, and the like.

  The output unit 20 outputs the result of processing by the processing unit 16. For example, the output unit 20 outputs an image generated as a result of processing by the processing unit 16 to a display device (not shown), and causes the display device to display the image. Alternatively, for example, the output unit 20 may output the processing result image to a device connected to the image processing apparatus 10 via the network by outputting the processing result image to a network (not shown). .

  FIG. 2 is a flowchart illustrating an example of a procedure of processing performed by the processing unit 16.

  With reference to FIG. 2, the processing unit 16 first acquires an original image to be processed from the image input unit 12 in step S <b> 1. In this example, the original image is digital data of a binary image.

  Next, in step S2, the processing unit 16 sets the processing direction to the main scanning direction of the original image. After step S3, each unit included in the processing unit 16 performs each process on the pixel line in the current processing direction.

  In step S3, the reduction unit of the processing unit 16 reduces the original image at a predetermined reduction rate in the current processing direction. For example, the reduction unit reduces each pixel line in the main scanning direction of the original image by 1 / f times (1.0 <f). The value of the reduction ratio 1 / f may be a value designated by the user, for example. The reduction unit can acquire the value of the reduction ratio 1 / f specified by the user via the user input unit 14. Alternatively, the reduction unit may use a reduction rate 1 / f that is preset and stored in the storage unit 18. The reduction unit performs reduction processing by a method generally used in image reduction conversion processing. For example, a plurality of pixels are selected from each pixel line of the original image at a fixed interval determined according to the reduction ratio 1 / f, and the value of each selected pixel is included in the corresponding pixel line of the reduction result image It is set as the value of each pixel. When the reduction process ends, the reduction unit 160 passes the reduction result image to the enlargement unit 162.

  In step S4, the enlargement unit 162 enlarges the reduction result image acquired from the reduction unit. The enlargement unit 162 enlarges the reduction result image in the set processing direction at an enlargement rate f represented by the reciprocal of the reduction rate 1 / f used by the reduction unit. For example, the enlargement unit 162 enlarges each pixel line in the main scanning direction of the reduction result image by f times. The enlargement unit 162 performs the enlargement process by a method corresponding to the method used by the reduction unit in the reduction process (step S3). It can be said that the enlargement process (step S4) of the enlargement unit 162 obtains an enlargement result image by inverse conversion of the conversion in the reduction process (step S3). For example, when the reduction processing is performed by the method of the above example in which the values of the pixels selected at regular intervals from each pixel line of the original image are the values of each pixel included in the pixel line of the reduction result image, For each pixel line of the reduction result image, the unit 162 sets a pixel line in which a predetermined number of pixels determined according to the enlargement ratio f are inserted between the pixels as the pixel line of the enlargement result image. Here, the value of the pixel inserted between the pixels may be set to the same value as one of the two pixels sandwiching the inserted pixel, for example. When the enlargement process ends, the enlargement unit 162 passes the enlargement result image to the reduced NG mask creation unit 164.

When some information loss occurs in the reduction process (step S3), the enlarged result image obtained by enlarging the reduced result image in step S4 maintains the information missing state in the reduced result image. For example, referring to FIG. 3, the pixel line A is one pixel line in the main scanning direction of the original image IMG _O. The pixel line B is a pixel line obtained by reducing the pixel line A to 1 / f times in the main scanning direction (the direction of the arrow M). That is, the pixel line B is a pixel line corresponding to the pixel line A of the original image IMG _O in the reduction result image. The pixel line C is a pixel line obtained by enlarging the pixel line B f times in the main scanning direction. That is, the pixel line C is a pixel line C corresponding to the pixel line A of the original image IMG _O in the enlarged result image.

In the pixel lines A of the original image IMG _O illustrated in FIG. 3, 1 between are arranged four black pixels in the portion p1 surrounded by a chain line, the black pixels and the black pixels of the adjacent Tsunoshiro Pixels are arranged. On the other hand, in the pixel line B of the reduced result image, four black pixels are continuously arranged in a portion corresponding to the portion p1 of the pixel line A, and are arranged between the black pixel and the black pixel in the pixel line A. The white pixels that have been deleted have disappeared. This indicates that the white thin line disappears due to the reduction process, and four independent black lines in the original image IMG _O are crushed and appear as one line in the reduction result image. In addition, one black pixel existing in the portion p2 surrounded by the alternate long and short dash line in the pixel line A has disappeared in the pixel line B. This represents that the black thin line in the original image IMG _O disappears in the reduction result image. Even in the pixel line C obtained by enlarging the pixel line B, there is no white pixel corresponding to the white pixel in the portion p1 of the pixel line A, and the black pixel corresponding to the black pixel in the portion p2 of the pixel line A is not exist. That is, the pixel line C of the enlarged result image reflects the information missing state in the pixel line B of the reduced result image. Therefore, by comparing the pixel line A of the original image IMG _O and the pixel line C of the enlarged result image, it is possible to determine a portion where information loss has occurred due to the reduction process.

  Referring to FIG. 2 again, in step S5, the reduced NG mask creating unit 164 creates a reduced NG mask by comparing the original image and the enlarged result image.

  FIG. 4 shows an example of a detailed procedure of the reduced NG mask creation process. When step S5 of FIG. 2 is started, the reduced NG mask creation unit 164 of the processing unit 16 starts processing of the procedure illustrated in FIG.

  Referring to FIG. 4, reduced NG mask creation unit 164 first initializes a reduced NG mask (step S50). In the initialization process, the reduced NG mask creation unit 164 creates, for example, a reduced NG mask including pixels corresponding to each pixel of the original image, and sets the NG mask values of all the pixels in the created reduced NG mask to OFF. To do. After the initialization process, the reduced NG mask creation unit 164 acquires one pixel line in the processing direction of the original image (step S51), and acquires a pixel line corresponding to this pixel line from the enlarged result image (step S52). ). For example, when the pixel line A in the example of FIG. 3 is acquired from the original image in step S51, the pixel line C in the example of FIG. 3 is acquired from the enlarged result image in step S52.

  Next, in step S54, the NG area determination unit 1640 of the reduced NG mask creation unit 164 obtains the target pixel line of the original image (obtained in step S51) and the corresponding pixel line of the enlarged result image (obtained in step S52). ), And the difference between the two is obtained. For example, in step S54, the NG area determination unit 1640 performs a logical AND operation on the value of each pixel of the pixel line of the original image and the value of each pixel of the pixel line of the corresponding enlarged result image. Thus, the position on the pixel line in which the pixel line pixel of the original image and the pixel line pixel of the enlarged result image have different values is obtained.

  Referring to FIG. 5, the line diff indicates the processing in step S54 by the NG area determination unit 1640 for the pixel line A of the original image in the example of FIG. 3 and the pixel line C of the enlarged result image in the example of FIG. An example of the result of performing is shown. In the line diff in FIG. 5, the hatched squares have different values for the pixel on the pixel line A and the pixel on the pixel line C corresponding to the position of this pixel (AND operation). The result is FALSE) representing the pixel position. The pixel position represented by the hatched square is a difference between the pixel line A and the pixel line C. Further, in the line diff, at the pixel position where the hatched square is not arranged, the pixel on the pixel line A and the pixel on the pixel line C have the same value (the result of the AND operation is TRUE).

  Returning to the description of FIG. 4, after obtaining the difference between the pixel line of the original image and the pixel line of the enlarged result image, in step S56, the NG area determination unit 1640 sets the pixel line of the enlarged result image to the same color. The pixel is divided into continuous portions. For example, the pixel line C in the example of FIG. 5 is divided into c0, c1, c2, c3, and c4. The portions c1 and c3 are portions where black pixels are continuous, and the portions c0, c2 and c4 are portions where white pixels are continuous.

  In step S58, the NG area determination unit 1640 selects one of the parts divided in step S56.

  Next, in step S60, the NG area determining unit 1640 determines whether or not the divided portion selected in step S58 includes a different portion between the pixel line of the original image and the pixel line of the enlarged result image. If a different part is included, the process proceeds to step S62. If a different part is not included, the process proceeds to step S64. For example, when the part c0 of the pixel line C in FIG. 5 is selected in step S58, the part corresponding to the part c0 in the line diff representing the difference between the pixel line A of the original image and the pixel line C of the enlarged image. Does not include a different portion (square with hatched lines), the process proceeds to step S64 as a result of the determination in step S60. Further, for example, when the part c1 of the pixel line C in FIG. 5 is selected in step S58, the part corresponding to the part c1 in the line diff includes a different part, so the process proceeds to step S62 as a result of the determination in step S60.

  In step S62, the NG area determination unit 1640 at least part of the pixels included in the portion corresponding to the division portion to be processed (selected in step S58) for the pixel line corresponding to the pixel line of the original image in the reduced NG mask. The NG mask value of is set to ON. The NG area determination unit 1640, for example, at a position corresponding to a pixel position of a different part that has been confirmed to exist in step S60 among pixels included in a part corresponding to the division part to be processed in the pixel line of the reduced NG mask. The NG mask value is set to ON for the pixel to be arranged and the pixel arranged at a position within a predetermined range from this pixel. Referring to FIG. 5, the pixel line NG is a pixel line corresponding to the pixel line A of the original image in the reduced NG mask. In the pixel line NG, the NG mask value of all the pixels included in the portion corresponding to the divided portion c1 of the pixel line C of the enlarged result image is set to ON, and the pixels included in the portion corresponding to the divided portion c2 of the pixel line C Among these, the position corresponding to the different part and the NG mask value of the pixel adjacent to the left are set to ON. As described above, an area composed of pixels having the NG mask value set to ON is an NG area, and is an area where it is determined that information loss occurs due to the reduction process of the reduction unit 160 (step S3 in FIG. 2).

  After step S62, the process proceeds to step S64.

  In step S64, the NG area determination unit 1640 determines whether or not all the divided parts of the pixel lines of the enlarged result image have been processed. If all the divided parts have not been processed, the process returns to step S58 to select one unprocessed divided part and repeat the processes of steps S60 to S64. If all the divided parts have been processed, the process proceeds to step S66.

  In step S66, the NG area determination unit 1640 determines whether or not all of the pixel lines in the processing direction of the original image have been processed. If all the pixel lines have been processed, the reduced NG mask creation process ends. If all the pixel lines have not been processed, the process returns to step S51 to obtain an unprocessed pixel line. Is repeated.

FIG. 6 shows an example of a reduced NG mask generated by the reduced NG mask creation process of the procedure illustrated in FIG. FIG. 6 is an example of a reduced NG mask when processing of the procedure illustrated in FIG. 4 is performed on the original image IMG _{O in} the example of FIG. The NG areas a1, a2, and a3 represented by the hatched squares in the reduced NG mask MSK represent areas that are determined to lack information when the original image IMG _O is reduced by the reduction unit 160, respectively. . For example, the NG areas a1 and a3 represent areas in which a plurality of black lines in the original image IMG _O are crushed due to the disappearance of white thin lines, and the NG area a2 represents an area in which the black thin lines disappear. .

  Returning to the description of FIG. 2, when the reduced NG mask creation processing (step S <b> 5 in FIG. 2, FIG. 4) ends, the reduced NG mask correction unit 1642 of the reduced NG mask creation unit 164 performs processing to correct the reduced NG mask. (Step S7). In the deformation / reduction process (step S8), which will be described later, for the original image, the NG area represented by the reduced NG mask and the area other than the NG area are reduced in the processing direction at different reduction rates. A pixel shift may occur in the direction. For example, referring to FIG. 6, broken lines l1, l2, l3, l4, and l5 correspond to the ends of each NG area in the vertical direction (direction perpendicular to the current processing direction M). When the deformation / reduction processing is performed according to the reduced NG mask MSK in the example of FIG. 6, pixel shift occurs in the processing direction in the image after deformation / reduction with respect to the pixel lines positioned above and below the broken lines l1, l2, l3, l4, and l5. . The reduced NG mask correcting unit 1642 of the reduced NG mask creating unit 164 corrects the reduced NG mask and reduces the portion where the pixel shift occurs due to the deformation / reduction process (step S8).

  FIG. 7 shows an example of a detailed procedure of the reduced NG mask correction process. When the reduced NG mask correction process (step S7) of FIG. 2 is started, the reduced NG mask correction unit 1642 starts the process of the procedure of the example of FIG.

  Referring to FIG. 7, first, in step S70, the reduced NG mask correcting unit 1642 determines whether or not an unprocessed NG area exists in the reduced NG mask created by the reduced NG mask creating unit 164. If an unprocessed NG area exists in the reduced NG mask, the process proceeds to step S72, and if not, the process ends.

  For example, in the reduction process (step S3 in FIG. 2), if no information loss occurs in any pixel line, the NG mask is not set to ON in the reduction NG mask creation process for any pixel line. (NO determination is always made in step S60 in FIG. 4), the reduced NG mask does not include an NG area. In this case, after the reduced NG mask correction process is started, the process proceeds to NO in the first determination in step S70, and the processes after step S72 are not performed.

  In step S72, the reduced NG mask correction unit 1642 selects one unprocessed NG area from the reduced NG mask.

  Next, in step S73, the reduced NG mask correction unit 1642 corrects the selected NG area so as to be a rectangle having sides parallel to the processing direction. For this purpose, the reduced NG mask correction unit 1642, for example, among the pixel lines in the processing direction passing through the selected NG area, 2 in the rectangular processing direction representing the outer frame of the reduced NG mask (corresponding to the outer frame of the original image). Two pixel lines closest to each of the sides are detected. Similarly, of the pixel lines in the direction perpendicular to the processing direction passing through the selected NG area, two lines closest to each of the two sides in the direction perpendicular to the rectangular processing direction of the outer frame of the reduced NG mask This pixel line is detected. Then, the selected NG area is made rectangular by setting the NG mask value of all the pixels included in the rectangular range formed by the four detected pixel lines to ON.

  As a specific example of the process in step S73, a process when the NG area a of the reduced NG mask MSK0 is a processing target will be described with reference to FIG. The reduced NG mask correcting unit 1642 includes two pixel lines u and d closest to two sides in the rectangular processing direction of the outer frame of the reduced NG mask among the pixel lines in the processing direction passing through the NG area a, and the reduced mask. The four pixel lines, i.e., the two pixel lines l and r closest to the two sides in the direction perpendicular to the rectangular processing direction of the outer frame are detected. Then, the NG mask value of the pixel within the rectangular range formed by the detected pixel lines u, d, l, r is set to ON. By the process of step S73, the smallest rectangle including all the selected NG areas is set as the NG area.

  Note that when an NG area that is a rectangle having a side parallel to the processing direction has already been selected, such as the NG areas a1, a2, and a3 in the example of FIG. 6, the process of step S73 can be omitted.

  In step S74, the reduced NG mask correction unit 1642 includes pixels whose NG mask value is set to ON in the pixel line immediately above the pixel line including the upper edge of the rectangle representing the selected NG area. It is determined whether or not. Here, the “upper edge” is one of the two sides in the processing direction of the rectangle representing the NG area, and the “upper pixel line” on the upper edge includes the upper edge. The pixel line that does not pass through the selected NG area among the two pixel lines in the processing direction adjacent to the pixel line.

  If the pixel line that is one pixel above the pixel line that includes the upper edge of the NG area includes a pixel for which the NG mask value is set to ON, the process proceeds from step S74 to step S76, and the pixel that is one level higher. In the line, the NG mask value of the pixel corresponding to the position of the selected NG area is set to ON. Then, this pixel line becomes a pixel line including a new upper edge of the selected NG area. Thereafter, the processes in steps S74 and S76 are repeated until it is determined in step S74 that the pixel line immediately above the pixel line including the upper edge of the NG area does not include a pixel with the NG mask value ON. If NO is determined in step S74, the process proceeds to step S78.

  For example, when the NG area a1 of the reduced NG mask MSK in the example of FIG. 6 is selected in step S72, the NG mask value is ON for the pixel line immediately above the pixel line including the upper edge of the NG area a1. There is no pixel set to. Therefore, the determination in step S74 proceeds to NO, and the determination in step S78 is performed.

  Further, for example, when the NG area a3 in the example of FIG. 6 is selected in step S72, the pixel line one pixel above the pixel line including the upper end of the NG area a3 passes through the NG areas a1 and a2, and therefore the NG mask value. Includes ON pixels. Therefore, the determination in step S74 proceeds to YES, and in step S76, the NG mask value of the pixel corresponding to the position of the NG area a3 is turned ON in the pixel line immediately above the pixel line including the upper edge of the NG area a3. And this pixel line becomes a pixel line including a new upper edge of the NG area a3. Then, when the processes of steps S74 and S76 are repeated and the upper edge of the NG area a3 reaches the position of the broken line l1, NO is determined in step S74 and the process proceeds to step S78.

  In step S78, it is determined whether the pixel line immediately below the pixel line including the lower edge of the NG area selected in step S72 includes a pixel whose NG mask value is set to ON. Note that the “lower edge” is the other edge parallel to the above “upper edge” in the rectangle representing the selected NG area, and the “lower pixel line” of the lower edge is the lower edge. Of the two pixel lines in the processing direction adjacent to the side, the pixel line does not pass through the selected NG area. If the pixel line immediately below the pixel line including the lower edge includes an NG mask value ON pixel, the process proceeds from step S78 to step S80, and the pixel line corresponds to the position of the selected NG area. The NG mask value of the pixel to be set is set to ON. This pixel line becomes a pixel line including a new lower edge of the selected NG area.

  For example, when the NG area a1 in the example of FIG. 6 is selected in step S72, the pixel line immediately below the pixel line corresponding to the lower edge of the NG area a1 passes through the NG area a3. Includes pixels that are set to ON. In this case, the process proceeds from step S78 to step S80.

  After step S80, the processes in steps S78 and S80 are performed until it is determined in step S78 that the pixel line immediately below the pixel line corresponding to the lower edge of the NG area does not include an NG mask ON pixel. If the determination is NO in step S78, the process returns to step S70.

  As a result of the reduced NG mask correction process of the procedure illustrated in FIG. 7, for example, a corrected reduced NG mask MSK ′ shown in FIG. 9 is generated. FIG. 9 is an example of a corrected reduced NG mask when the reduced NG mask correction process of the example of FIG. 7 is performed on the reduced NG mask MSK of the example of FIG. Referring to FIG. 9, each of the NG areas a1 ′, a2 ′, a3 ′ included in the corrected reduced NG mask MSK ′ has the same length in the direction perpendicular to the main scanning direction M, and The uppermost pixel line and the lowermost pixel line are positioned on one straight line (broken lines 11 and 15 respectively). According to the correction reduction NG mask MSK ′ in the example of FIG. 9, pixel displacement in the main scanning direction M may occur for the pixel lines above and below the broken lines 11 and 15 in the deformation reduction process (step S <b> 8 in FIG. 2) described later. However, pixel shift does not occur in the pixel lines above and below the broken lines l2, l3, and l4.

  Returning to the description of FIG. 2, when the reduced NG mask correction process (step S7, FIG. 7) ends, the deformation / reduction unit 166 reduces the original image according to the corrected reduced NG mask in step S8. For example, the deformation / reduction unit 166 reduces (that is, does not reduce) the NG area represented by the corrected reduction NG mask in the current processing direction with a reduction ratio of 1.0 (in other words, does not reduce the area). Reduce to 1 / f times.

Hereinafter, an example of the deformation reduction process performed by the deformation reduction unit 166 will be described with reference to FIGS. 10 and 11. Referring to FIG. 10, the original image IMG _O and the corrected reduced NG mask MSK ′ are the same as the original image IMG _{O in} FIG. 3 and the corrected reduced NG mask MSK ′ in FIG. 9, respectively. The deformation reduction unit 166 deforms each pixel line in the main scanning direction M of the original image IMG _O with reference to the NG mask value of each pixel included in the pixel line of the correction reduction NG mask MSK ′ corresponding to this pixel line. Perform reduction processing. In FIG. 10, the image IMG _M after this deformation / reduction is shown below the original image IMG _O. In the post-deformation / reduction image IMG _M shown in FIG. 10, the regions surrounded by the alternate long and short dash line correspond to the NG areas in the correction reduction NG mask MSK ′. In FIG. 10, the pixel line A in the original image IMG _O and the pixel line E corresponding to the pixel line A in the corrected reduced NG mask MSK ′ between the original image IMG _O and the deformed and reduced image IMG _M In addition, a pixel line F corresponding to the pixel line A in the deformed / reduced image IMG _M is shown.

Hereinafter, a case where the deformation reduction process for the pixel lines A of the original image IMG _O will be described as an example. First, the deformation reduction unit 166 acquires the pixel line E of the correction reduction NG mask MSK ′ corresponding to the pixel line A. Then, a part of the pixel line E where the NG mask value is set to ON is detected, and a part of the pixel line A corresponding to the part of the NG mask value ON is detected. Since the pixel line E passes through the NG areas a1 ′, a2 ′, and a3 ′, portions included in the NG areas a1 ′, a2 ′, and a3 ′ on the pixel line E are detected. As the portions of the pixel line A corresponding to the portions of the NG areas a1 ′, a2 ′, and a3 ′ detected on the pixel line E, portions of lengths L ₂ , L ₄ , and L ₆ are detected, respectively. Next, for the pixel line A, the deformation / reduction unit 166 has a reduction ratio of 1.0 for portions corresponding to the NG area (lengths L ₂ , L ₄ , L ₆ ), and a portion other than the portion corresponding to the NG area ( The lengths L ₁ , L ₃ , L ₅ , L ₇ ) are reduced in the main scanning direction at a reduction ratio of 1 / f. Here, the lengths L ₁ , L ₃ , L ₅ , and L ₇ are reduced by the same method as the method used by the reduction unit 160 in the reduction process (step S3 in FIG. 2). In the pixel line F obtained by deforming and reducing the pixel line A, the lengths of the portions corresponding to the lengths L ₁ , L ₃ , L ₅ and L ₇ of the pixel line A are L ₁ / f, L ₃ / f, L ₅ / f, and L ₇ / f. In the pixel line F, the lengths of the portions corresponding to the lengths L ₂ , L ₄ and L ₆ of the pixel line A remain as L ₂ , L ₄ and L ₆ , respectively.

11 shows an example of the results was performed deformation reduction processes described above the pixel lines A Examples in each of all the lines of pixels in the original image IMG _O. Referring to FIG. 11, the original image IMG _O, depending whether including NG area representing the correction reduction NG mask MSK' (region surrounded by a chain line), the length of one side in the main scanning direction of the original image IMG _O Are divided into rectangular areas (area 1, area 2, area 3) having a width W _O of the first and second areas. Area 1 and area 3 do not include an NG area, and area 2 includes an NG area. The widths of areas 1, 2, and 3 as a result of performing the above-described deformation / reduction processing for each pixel line of the original image are W ₁ , W ₂ , and W ₃ , respectively. Since area 1 and area 3 do not include the NG area, the area is reduced to 1 / f times in the main scanning direction as a whole, and W ₁ = W ₃ = W _O / f = (L ₁ + L ₂ + L ₃ + L ₄ + L ₅₎ + L ₆ + L ₇ ) / f. For the area 2 including the NG area, as described with reference to FIG. 10, the portion (L ₂ , L ₄ , L ₆ ) that is not reduced and the portion (L ₁ , L ₃ , L ₅ , L ₇ ) and W ₂ = L ₂ + L ₄ + L ₆ + (L ₁ + L ₃ + L ₅ + L ₇ ) / f. Therefore, W ₁ = W ₃ <W ₂ . In this state, there is no pixel in the region corresponding to the difference between W1 or W3 and W2 (the region indicated by the broken line in FIG. 11). These regions are complemented with, for example, pixels of the background color (white in this example). Or you may complement by the pixel which has the average value of the pixel value in the pixel line corresponding to these area | regions. By performing pixel complementation processing in this way, a post-transformation reduced image IMG _M (see FIG. 10) having a width W ₂ is generated.

  In the above, the example of the deformation | transformation reduction process (step S8 of FIG. 2) by the deformation | transformation reduction part 166 was demonstrated. In the deformation / reduction process of this example, the area (NG area) in which information loss has occurred in the reduction process (step S3) is not reduced, and the area in which no information loss has occurred in the reduction process (area other than the NG area) Then, reduction is performed using the same method and reduction ratio as those used in the reduction processing. Therefore, no information is lost in the deformation reduction process of this example.

  Returning to the description of FIG. 2, when the deformation / reduction process (step S8) is completed, it is determined whether or not the process has been completed in the sub-scanning direction (step S9). If not processed, the processing direction is set to the sub-scanning direction (step S10), and the processing after step S3 is performed. If the processing has been completed for the sub-scanning direction, the processing of the procedure in the example of FIG. 2 ends.

  FIG. 12 is a block diagram illustrating an example of a schematic configuration of an image processing apparatus according to another embodiment. In FIG. 12, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. The processing unit 17 of the image processing apparatus 11 illustrated in FIG. 12 includes an image width adjustment unit 168 in addition to the components of the processing unit 16 of the image processing apparatus 10 in the example of FIG.

  The image width adjustment unit 168 reduces the reduction ratios of various regions in the original image so that the width of the image after deformation / reduction approaches the target width as long as no information is lost in the deformation / reduction processing of the deformation / reduction unit 166. Or the process which determines the width | variety after reduction is performed.

The image width adjustment unit 168 includes an image width calculation unit 1680 and a margin adjustment unit 1682. The image width calculation unit 1680 calculates the width of the image as a result of the deformation / reduction performed by the deformation / reduction unit 166. For example, the image width calculation unit 1680 performs a process of calculating each value of the widths W ₁ , W ₂ , and W ₃ in the example of FIG.

  The margin adjustment unit 1682 detects a margin in the original image, and detects the detected margin so that the detected margin is smaller than when the reduction is performed at the reduction ratio used for the reduction of the area other than the NG area in the deformation reduction process. Performs the process of determining the reduction ratio of the margin or the width after reduction.

  FIG. 13 is a flowchart illustrating an example of a procedure of processing performed by the processing unit 17 of the image processing apparatus 11 illustrated in FIG. In FIG. 13, processing steps that perform the same processing as the processing illustrated in FIG. 2 are denoted by the same reference numerals as in FIG. 2.

  Referring to FIG. 13, first, the processing unit 17 acquires an original image (step S1), and sets the processing direction to the main scanning direction (step S2).

  Next, the processing unit 17 creates a corrected reduced NG mask using the reduction ratio 1 / f (step S30). The value of the reduction ratio 1 / f may be a value designated by the user as in the process of the procedure illustrated in FIG. 2 or may be a value set in advance and stored in the storage unit 18. . In step S30, a corrected reduced NG mask is generated by a process similar to the process of steps S3 to S7 described with reference to FIGS.

In step S40, the image width calculation unit 1680 of the image width adjustment unit 168 displays an image after deformation / reduction when the deformation / reduction unit 166 deforms / reduces the original image according to the corrected reduction / NG mask generated as a result of the process of step S30. The width of is calculated. Here, the “image width” means the size of the image in the current processing direction. The image width calculation unit 1680 calculates the image width by the following procedure, for example. First, the image width calculation unit 1680 divides the original image into rectangular regions having one side having the same size as the width W _{O of the} original image, according to whether or not the NG area represented by the corrected reduced NG mask is included. For example, in the case of the original image IMG _O and the corrected reduced NG mask in FIG. 11, the original image IMG _O is divided into area 1, area 2, and area 3. Next, one pixel line is selected from each of the divided areas, and the length of each pixel line as a result of performing the deformation / reduction process according to the correction reduction NG mask is calculated. The length of each pixel line is the width after deformation of each divided area. In the example of FIG. 11, the widths W ₁ , W ₂ , and W ₃ after deformation / reduction of the area 1, area 2, and area 3 of the original image IMG _O are calculated.

In step S42, the image width adjustment unit 168 determines whether or not the maximum value of the width obtained by the image width calculation unit 1680 in step S40 is 1 / f times or less the width W _O of the original image. In the example of FIG. 11, it is determined whether or not the width W ₂ having the maximum value among the widths W ₁ , W ₂ , and W ₃ calculated in step S40 is equal to or less than 1 / f times the width W _O of the original image. To do.

  If the maximum value of the image width after deformation / reduction exceeds 1 / f times the width of the original image, the process proceeds to image width adjustment processing (step S44).

  FIG. 14 is a flowchart illustrating an example of a detailed procedure of image width adjustment processing.

  Referring to FIG. 14, first, the margin adjustment unit 1682 sets an area in the original image having the maximum width after deformation and reduction as a target area. For example, area 2 in the example of FIG. 11 is the target area. Then, in the target area, a rectangular blank having one side having the same length as the side of the target area in the direction perpendicular to the processing direction is detected from the areas other than the NG area represented by the correction reduced NG mask (step S440). . Here, the “margin” means a portion composed only of background color pixels of the original image. In the following, the margin detected in step S440 of FIG. 14 may be referred to as “vertical margin”.

Referring to FIG. 15, gray rectangles bl1, bl2, bl3, and bl4 are examples of vertical margins detected when the process of step S440 is performed on the original image IMG _{O in} the example of FIG. Each of the vertical margins bl1, bl2, bl3, and bl4 has one side having the same length as the side of the area 2 in the sub-scanning direction (direction perpendicular to the main scanning direction M).

  Referring to FIG. 14 again, after detecting the vertical margin, the margin adjustment unit 1682 makes the width after the deformation reduction process smaller than 1 / f times the original width for each of the detected vertical margins. The width of the vertical margin is adjusted (step S442). For example, the area corresponding to each vertical margin in the corrected reduction NG mask is associated with information instructing to perform the deformation reduction process so that the width after the deformation reduction becomes one pixel width. Alternatively, for example, if a plurality of vertical margins are detected, the width ratio of the detected vertical margins is maintained, and the width is smaller than 1 / f times the original vertical margin width. Information instructing to perform the reduction process may be associated with an area corresponding to each vertical margin in the corrected reduced NG mask.

  Next, in step S444, the image width calculation unit 1680 calculates the width of the target area after deformation / reduction using the width of the vertical margin after deformation / reduction adjusted in step S422. For example, in the case of the area 2 in FIG. 11, the widths of the vertical margins bl1, bl2, bl3, and bl4 in FIG. 15 are set to one pixel width, and the widths of the portions corresponding to the NG area remain L2, L4, and L6. The width of the area 2 after deformation reduction is calculated by setting the width of the portion not corresponding to any of the NG area and the vertical margin as 1 / f times the original width.

Next, it is determined whether or not the width of the target area calculated in step S444 is 1 / f or less of the width W _O of the original image (step S446), and if it is less than or equal to the target image width (W _O / f). If the target image width (W _O / f) is exceeded, the process proceeds to step S448.

  In step S <b> 448, the processing unit 17 represents that the width of the image after deformation / reduction exceeds the target image width even if the deformation / reduction processing is performed after adjusting the width of the vertical margin via the output unit 20. Output warning information. For example, by outputting this warning information to a display device (not shown) and displaying it, it is possible to notify the user that the image width after deformation reduction after vertical margin adjustment exceeds the target image width.

In step S450, it is determined whether to execute again the process of creating a corrected reduced NG mask for the original image using a reduction ratio 1 / (f−α) larger than the current reduction ratio 1 / f. That is, it is determined whether or not to perform the process of creating the corrected reduction NG mask by reducing the original image more slowly than the reduction unit 160 reduces the current reduction ratio 1 / f. Here, the value of α is, for example, the value at the beginning of the f of the processing of FIG. 13 as f _ST, the following formula:
1 / f _ST <1 / (f _ST −α) <1.0
Is set in advance to a constant in the range of 0 <α <f _ST −1.0. If it is decided to execute the correction reduced NG mask generation process again, the value of f is set to f−α (that is, the reduction ratio 1 / f is set to 1 / (f−α)) in step S452, and FIG. Returning to step S30, the processes after step S30 are performed again. When it is determined not to execute the correction / reduction NG mask creation process again, the image width adjustment process ends.

  The determination in step S450 is performed according to a user instruction, for example. For example, in step S448, information prompting the user to input whether or not the user desires to execute a correction reduced NG mask creation process using a new reduction ratio 1 / (f−α) together with the above-described warning information. Is displayed on the display device, the process proceeds from step S450 to step S452 when the user receives an input indicating that execution is desired, and the process is terminated when the user receives an input indicating that execution is not desired. Alternatively, for example, in step S450, if 1 / (f−α) is within a predetermined value range, the process may proceed to YES, and if it is outside the predetermined value range, the process may proceed to NO. This value range is set to a value range 0 <1 / (f−α) <1.0, which is appropriate as a reduction ratio used in the reduction process of the reduction unit 160, for example. If both the conditions that the user has received an input indicating that execution is desired and the value of 1 / (f−α) is within a predetermined range are satisfied, the process proceeds to YES in step S450. Good.

  Returning to the description of FIG. 13, in step S8, deformation and reduction are performed according to the correction reduction NG mask. If instruction information regarding vertical margin reduction is set in the corrected reduced NG mask by the image width adjustment process, the deformation reduction unit 166 determines the width of the vertical margin after deformation reduction according to the instruction information. For regions other than the vertical margin of the corrected reduced NG mask, processing similar to the deformation reduction processing in step S8 of FIG. 2 described with reference to FIGS. 10 and 11 is performed according to whether the NG mask value is ON or OFF. .

  If the sub-scanning direction has not been processed after the deformation reduction process (NO in step S9), the processing direction is set to the sub-scanning direction (step S10), and the processes after step S30 are performed in the sub-scanning direction. If the process has been completed for the sub-scanning direction (YES in step S9), the process ends.

  As described above, according to the processing of the procedure illustrated in FIG. 13 and FIG. 14, the image after deformation / reduction is an original image with the reduction ratio 1 / f set at the start of the processing of FIG. It has the width closest to the width when. For example, when the process of FIG. 13 is started using the reduction ratio 1 / f specified by the user, a deformed and reduced image having a size closest to the image size desired by the user can be obtained within a limit where no information is lost. . Further, for example, when the process of FIG. 13 is started using a reduction ratio 1 / f that is sure to cause information loss, a deformed and reduced image having a minimum size that does not cause information loss is obtained.

  Hereinafter, another example of the detailed procedure of the image width adjustment process (step S44 in FIG. 13) will be described with reference to FIGS. 14, 16, and 17. FIG.

In the image width adjustment process of this example, the image width adjustment unit 168 first performs the processes of steps S440 to S448 described with reference to FIG. If the width of the target area after the adjustment of the width of the vertical margin exceeds the target width (W _O / f) (NO in step S446), warning information indicating that is output (step S448). ), The image width adjustment unit 168 starts the processing of the procedure illustrated in FIG.

Referring to FIG. 16, first, in step S460, it substitutes the value of the current reduction ratio 1 / f in the target reduction ratio 1 / f _T. Next, one NG area is selected from the NG areas included in the target area (step S462), and the possible reduction ratio 1 / fmin is determined for the selected NG area (step S464). The possible reduction ratio 1 / fmin is a reduction ratio at which the size of the image after reduction is the smallest among the reduction ratios in which information loss does not occur when the reduction processing of the reduction unit 160 is performed on the processing target image.

  When the possible reduction rate determination process (step S464) is started, the image width adjustment unit 168 starts the process of the procedure illustrated in FIG.

Referring to FIG. 17, it is determined in step S600 whether 0 <1 / (f−α) <1.0. Here, the value of α is, for example, in the range of 0 <α <f _ST −1 (f _ST is the start of the processing of FIG. 13), similar to α in the processing of steps S450 and S452 described with reference to FIG. It is set to a constant of the value of time f).

  If YES in step S600, f-α is set as a new value of f in step S602. Next, a corrected reduced NG mask creation process (step S30) is performed using the reduction ratio 1 / f for the NG area selected in step S462 in FIG. In step S30, the selected NG area is used as the original image and the processing of steps S3 to S7 described with reference to FIGS. 2 to 9 is executed using the reduction ratio 1 / f. A corrected reduced NG mask for the NG area is created.

  After step S30, it is determined whether or not there is an NG area in the corrected reduced NG mask created for the selected NG area (step S604). If it is determined in step S604 that an NG area exists in the corrected reduced NG mask, the process returns to step S600, and the processes in and after step S600 are repeated. If it is determined in step S604 that there is no NG area in the corrected reduced NG mask, the current f value is set as the fmin value (step S606), and the possible reduction ratio 1 / fmin is determined. The process in FIG. 17 ends.

  The value of the reduction ratio 1 / f used in step S30 is larger than the value of the reduction ratio used in the previous correction reduction NG mask creation process for the selected NG area. Therefore, in step S604, it is determined whether or not information loss occurs when the selected NG area is reduced at a more gradual reduction rate when information loss occurs when the selected NG area is reduced using a certain reduction rate. I can say that.

  If the processing loop including steps S600, S602, and S604 is repeated, the value of 1 / (f−α) may fall outside the range of 0 <1 / (f−α) <1.0. In this case, the determination in step S600 proceeds to NO, and 1.0 is set as the value of f (step S608). The process proceeds to step S606, and the value of the possible reduction ratio 1 / fmin is determined to be 1.0.

  In the corrected reduced NG mask created for the original image in step S30 in FIG. 13, the NG area that is the target of the possible reduction ratio determination process in the example of FIG. 17 is deformed at the determined possible reduction ratio 1 / fmin. Information for instructing to perform reduction processing is set.

  Referring to FIG. 16 again, when the possible reduction ratio determination process (step S464, FIG. 17) ends, in step S466, the image width calculation unit 1680 calculates the width of the target area after deformation / reduction. In step S466, the NG area that has already been subjected to the possible reduction ratio determination process is reduced at the determined possible reduction ratio 1 / fmin, and the NG area that has not yet been subjected to the possible reduction ratio determination process has a reduction ratio of 1.0. The width of the target area when the image is reduced and deformed / reduced is calculated. In step S466, the width of the target area is further calculated in consideration of the result of the vertical margin adjustment process in step S442 of FIG.

If the width of the target area calculated in step S466 is equal to or less than 1 / f _T times the width W _O of the original image, the image width adjustment process ends, and the calculated width of the target area is the target image width W _O / f. If it exceeds _T , the process proceeds to step S470. In step S470, it is determined whether all NG areas included in the target area have been processed. If there is NG area untreated, sets the value of f _T as the value of f proceeds to step S474, the process returns to step S462, selects one NG area unprocessed, step S464 the following process repeat.

  If it is determined in step S470 that all NG areas included in the target area have been processed, in step S472, the image width adjustment unit 168 enables all NG areas in the target area via the output unit 20. Even if the image width is reduced as much as possible, information indicating that the image width after deformation reduction exceeds the target image width is output, and the image width adjustment processing ends.

  As described above, in the example of the image width adjustment processing described with reference to FIGS. 14, 16, and 17, since the NG area is present in the original image, the image width after deformation / reduction exceeds the target image width, By creating a reduced NG mask using a larger reduction ratio for each NG area, a possible reduction ratio at which no information loss occurs in the NG area is obtained. In the deformation reduction process (step S8 in FIG. 13), each NG area is reduced using the possible reduction ratio of the NG area instead of using the reduction ratio 1.0. By performing both adjustment of the width of the vertical margin (step S442 in FIG. 14) and reduction according to the possible reduction ratio of each NG area, a deformed and reduced image having a width equal to or smaller than the target image width without causing information loss is obtained. May be obtained.

  In the above description, the possible reduction rate determination process of FIG. 17 has been described as part of the procedure of the image width adjustment process. However, the possible reduction rate determination process of FIG. 17 may be performed on the original image as a processing target. When the possible reduction rate determination process of FIG. 17 is performed on the original image, the possible reduction rate of the original image can be obtained.

  Further, the processing unit 17 of the image processing apparatus 11 in the example of FIG. 12 performs, for each NG area included in the corrected reduced NG mask of the original image, the image width adjustment processing in the above two examples using the NG area as the original image. The process of the procedure of the example of FIG. 13 including any of the above can also be recursively executed.

  In the example of the deformation / reduction process of the various embodiments described above, the reduction process is performed at different reduction ratios for different regions in the original image according to the corrected reduction / NG mask. Therefore, in the above-described various examples of deformation / reduction processing, the length and thickness of lines in an image may be converted at different ratios depending on the area in the original image. However, the connection relationship between lines in the original image and the presence of lines in the original image are also preserved in the image after the deformation / reduction process. Therefore, when the deformation / reduction processing of the above-described various examples is performed on an image in which the connection relationship between elements and the presence of a line give meaning to the drawing, such as an electric circuit diagram, the meaning of the information represented in the drawing is changed. The image is reduced.

  The image processing apparatuses 10 and 11 according to the embodiments described above are typically realized by executing a program describing functions or processing contents of each unit of the electronic document processing apparatus described above on a general-purpose computer. . In the computer, for example, as shown in FIG. 18, a CPU (central processing unit) 60, a memory (primary storage) 62, various I / O (input / output) interfaces 64, and the like are connected via a bus 66 as hardware. Circuit configuration. An input device 68 such as a keyboard and a mouse and a display device 70 such as a CRT (Cathode Ray Tube) and a liquid crystal display are connected to the bus 66 via, for example, an I / O interface 64. Also, the bus 66 has an HDD (Hard Disk Drive) 72 and a disk drive 74 for reading portable non-volatile recording media of various standards such as a CD, a DVD and a flash memory via an I / O interface 64. Connected. Such drives 72 and 74 function as an external storage device for the memory. The program describing the processing contents of the embodiment is stored in a fixed storage device such as the HDD 72 via a recording medium such as a CD or DVD or via a network, and is installed in a computer. The programs stored in the fixed storage device are read out to the memory 62 and executed by the CPU 60, whereby the processes of the various embodiments described above are realized.

It is a block diagram which shows the structural example of the image processing apparatus of one Embodiment of this invention. 2 is a flowchart illustrating an example of a procedure of processing performed by a processing unit of the image processing apparatus in the example of FIG. 1. It is a figure which shows an example of the mode of the information missing produced by the reduction process of an image. It is a flowchart which shows an example of the procedure of a reduced NG mask creation process. It is a figure for demonstrating the example of the process which determines a NG area. It is a figure which shows an example of the reduction | restoration NG mask produced with respect to an original image. It is a flowchart which shows an example of the procedure of a reduction NG mask correction process. It is a figure for demonstrating the example of a part of procedure of a reduction NG mask correction process. It is a figure which shows an example of the correction | amendment reduction NG mask which correct | amended the reduction NG mask. It is a figure for demonstrating the example of a deformation | transformation reduction process. It is a figure for demonstrating the example of a deformation | transformation reduction process. It is a block diagram which shows the structural example of the image processing apparatus of other one Embodiment of this invention. 13 is a flowchart illustrating an example of a processing procedure performed by a processing unit of the image processing apparatus illustrated in FIG. 12. It is a flowchart which shows an example of the procedure of an image width adjustment process. It is a figure for demonstrating the example of the process which adjusts the width | variety of a margin. It is a flowchart which shows another example of the procedure of an image width adjustment process. It is a flowchart which shows an example of the procedure of a possible reduction rate determination process. It is a figure which shows an example of the hardware constitutions of a computer.

Explanation of symbols

  10, 11 image processing device, 12 image input unit, 14 user input unit, 16, 17 processing unit, 18 storage unit, 20 output unit, 62 memory, 64 interface, 66 bus, 68 input device, 70 display device, 72 HDD 74 disk drive, 160 reduction unit, 162 enlargement unit, 164 reduction NG mask creation unit, 166 deformation reduction unit, 168 image width adjustment unit, 1640 NG area determination unit, 1642 reduction NG mask correction unit, 1680 image width calculation unit, 1682 Margin adjustment unit.

Claims (11)

A reduction unit that reduces the original image at a predetermined reduction rate;
By comparing information acquired based on the image of the reduction result by the reduction unit and information acquired based on the original image, the image corresponding to a region where image quality degradation occurs in the reduction result image An image quality degradation area determination unit that determines an image quality degradation area that is an area in the original image;
A deformation / reduction unit that reduces the original image using different reduction ratios for the image quality degradation region and the other regions in the original image of the image quality degradation region;
An image processing apparatus comprising: An enlargement unit for enlarging the reduction result image using an inverse of the predetermined reduction rate used by the reduction unit as an enlargement rate;
The image quality degradation region determination unit includes a value of each pixel included in an image as a result of enlargement by the enlargement unit and a pixel disposed at a position in the original image corresponding to the position of the pixel in the enlargement result image. The image processing apparatus according to claim 1, wherein the image quality degradation region is determined by comparing the value.   The deformation / reduction unit does not reduce the image quality deterioration region, and reduces other regions in the original image other than the image quality deterioration region at the predetermined reduction ratio used by the reduction unit. The image processing apparatus according to claim 1.   An image quality deterioration region correction unit that corrects the region based on the position of the region determined by the image quality deterioration region determination unit in the original image and sets the corrected region as the image quality deterioration region; The image processing apparatus according to any one of claims 1 to 3.   After performing processing of each unit included in the image processing apparatus with one scanning direction of the original image as a processing direction, processing of each unit included in the image processing apparatus is performed with a direction perpendicular to the scanning direction as a processing direction. The image processing apparatus according to claim 1, wherein the image processing apparatus is an image processing apparatus. From a region in the original image other than the image quality degradation region, a margin that is a rectangular region having sides parallel to the processing direction and includes only pixels representing the background color of the original image is detected, A margin adjustment unit that instructs the deformation / reduction unit to reduce the size of the detected margin to a size smaller than the size when reduced at the predetermined reduction rate;
Further comprising
The image processing apparatus according to claim 5, wherein the deformation reduction unit further reduces the original image according to an instruction from the margin adjustment unit.   The size of the image after reduction by the deformation reduction unit is obtained, and when the obtained size is larger than the size of the reduction result image, the predetermined reduction rate used by the reduction unit for the original image The image processing apparatus according to claim 6, wherein processing of at least the reduction unit, the image quality degradation region determination unit, and the margin adjustment unit is executed using different reduction ratios.   The size of the image after reduction by the deformation reduction unit is obtained, and when the obtained size is larger than the size of the reduction result image, each of the image quality degradation regions is used as an original image by the reduction unit. 5. The image processing apparatus according to claim 1, wherein at least processing of the reduction unit and the image quality degradation area determination unit is executed using a reduction rate different from the predetermined reduction rate. 6. .   Using the image designated as the processing target as an original image, the processing of at least the reduction unit and the image quality degradation area determination unit is repeatedly performed using a plurality of different reduction ratios, and the image quality degradation area is determined by the image quality degradation area determination unit. A possible reduction ratio that determines, as a possible reduction ratio of the designated image, a reduction ratio that minimizes the size of the image after reduction among the reduction ratios used by the reduction unit when it is determined that the image does not exist. The image processing apparatus according to claim 1, further comprising a determination unit. Specifying each of the image quality degradation regions as a processing target and executing the processing of the possible reduction rate determination unit,
The image processing device according to claim 9, wherein the deformation reduction unit reduces the image quality degradation region using the possible reduction rate determined by the possible reduction rate determination unit for each of the image quality degradation regions. . A reduction step for reducing the original image at a predetermined reduction rate;
By comparing the information acquired based on the image of the reduction result obtained by the reduction step with the information acquired based on the original image, the image corresponding to the region where the image quality is degraded in the reduction result image. An image quality degradation area determination step for determining an image quality degradation area that is an area in the original image;
A deformation reduction step of reducing the original image using different reduction ratios for the image quality deterioration region and the other regions in the original image of the image quality deterioration region;
A program that causes a computer to execute.

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