JP2002185791A - Image processing unit, image processing method and recording medium, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing unit that distinguishes an image on the front side of an original from an image on the other side so as to be able to apply set-off reduction processing proper to the respective images. SOLUTION: The image processing unit of this invention is provided with an image input section 10 that receives an image printed on paper in color as digital color image data, an area discrimination section 20 that discriminates in which of an area in a color on the or the other area the received image exists according to the feature quantity, and a reduction processing section 40 that applies the set-off reduction processing suitable for the respective images based on the discriminated result so as to reduce the set-off caused on both the paper color area and the other area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image processing apparatus, an image processing method, a recording medium, and an image forming apparatus.
More specifically, the present invention relates to a technique for reducing show-through or lay-through in digital color image processing, and is particularly suitable for application to a color image forming apparatus such as a color copying machine, a color printer, and a color facsimile.

[0002]

2. Description of the Related Art With the spread of image input devices such as scanners, digital cameras, and digital copiers, when inputting paper documents such as books, magazines, catalogs, advertisements, and newspapers,
When these documents are printed on both sides of a thin sheet of paper having high transmittance, the image on the back side may be transparent and “show-through” may be input in the image on the front side. In order to eliminate such show-through, a method of detecting and reducing show-through components from an image on one side without mechanically devising a pressing plate or the like has been proposed (Japanese Patent Laid-Open No. 7-3075).
7, JP-A-7-298055 and JP-A-10
-65521, JP-A-10-257325, JP-A-11-187266 and the like). These methods aim to support not only normal images but also images with many stains by determining a noise removal threshold from the distribution of the histogram of the luminance of the document.
In addition to requiring a histogram of the entire image in advance,
Since only the threshold value for removing the noise is adaptively changed, if the luminance of the highlight region of the surface image is higher than the luminance of the show-through region, the surface image may not always be reproduced. Also, Japanese Patent Application Laid-Open No. 2000-20943
In Japanese Patent Application Laid-Open No. H8-264409 and Japanese Patent Application Laid-Open No. H7-264409, the highlight region of the surface image is retained and the show-through is removed by determining the characteristics of the surface image and determining whether or not to perform show-through removal. It is intended to be. JP 2000
Japanese Patent Application Laid-Open No. 209438 uses color information and the number of edges in a window as feature values. However, when a thin highlight area is represented by a halftone dot with a low screen ruling, the area may not be able to be retained. Japanese Patent Application Laid-Open No. 7-264409 calculates the saturation and the density level (luminance) for each pixel value,
Pixels whose saturation is higher than the threshold value or whose density level is lower than the threshold value are regarded as pixels constituting the foreground image. For this reason, in a thin highlight area represented by halftone dots with a low screen ruling as in Japanese Patent Application Laid-Open No. 2000-209438, since some pixels inside the area are corrected, the appearance of the area in the output may be different from that of the original. It can change.

All of the above-mentioned conventional techniques can deal only with show-through on a white background of paper, and cannot deal with show-through occurring in a halftone area or the like. In general, in the print area and the paper area, the print area has lower brightness, and the paper area has the highest transmittance in the document except for special paper quality. Therefore, in general, show-through tends to be stronger in the paper area than in the print area. However, in the technique of Japanese Patent Application No. 11-354412 filed by the present applicant, the color edge strength is mainly reduced in the show-through area. Because of this, the intensity of show-through is different, and it is difficult to cope with the show-through of the print area and the show-through of the paper area in a single method.

[0004]

However, as in the prior art described above, the correspondence between print-through and show-through of a paper area for a single document is determined by a single threshold value. If the processing is performed as a background removal process or the like, a trade-off will occur between preservation of a highlight area and removal of show-through. Further, in the show-through reduction processing specialized for the highlight area, there is a problem that it is difficult to deal with show-through generated on a white background due to a difference in strength of show-through. SUMMARY An advantage of some aspects of the invention is to provide an image processing apparatus capable of distinguishing an image on a front surface of an original from an image other than the original and performing a show-through reduction process suitable for each of the images. It is an object to provide an image processing method, a recording medium, and an image forming apparatus.

[0005]

According to a first aspect of the present invention, there is provided an image processing apparatus comprising: an image input unit for inputting an image color-printed on paper as digital color image data; An area discriminating section for discriminating whether the input image is in a paper color area or another area based on the image feature amount, and a reduction processing section for performing show-through reducing processing suitable for each of the areas based on the discrimination result. To reduce the show-through generated in both the paper color and the other area. According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, brightness, saturation,
It is characterized by using edge strength. Claim 3
In the image processing apparatus according to the present invention, in the image processing apparatus according to claim 2, the area determination unit compares the hue information of a specific paper color and the hue information of the input image to determine a paper color area. Is determined. Claim 4
In the image processing apparatus according to the present invention, in the image processing apparatus according to claim 2, the area determination unit determines whether the area is a paper color area based on hue information of a specific paper color and hue information of an input image. Discriminating, and when the reduction processing unit determines that the area is the paper color area,
Alternatively, it is characterized in that it is possible to instruct whether to leave. The image processing apparatus according to the fifth aspect of the present invention provides the image processing apparatus according to the first aspect.
The image processing apparatus according to any one of claims 1 to 4,
The reduction processing unit performs a reduction process using only information inside a local window when the area determination unit determines that the area is outside the paper color. An image processing apparatus according to a sixth aspect of the present invention provides an image processing apparatus comprising: an image input unit for inputting an image color-printed on paper as digital color image data; A region discriminating unit for discriminating whether or not there is an image feature amount of brightness, saturation, edge intensity, and hue, and performing a show-through reduction process suitable for each according to the discrimination result by the region discriminating unit, thereby obtaining a paper color. And a reduction processing unit that reduces show-through generated in both the other areas.

[0006] An image processing apparatus according to a seventh aspect of the present invention comprises:
7. The image processing apparatus according to claim 6, wherein the reduction processing unit performs a process using only information inside a local window when the area determination unit determines that the area is not a paper color. And According to the image processing method of the present invention, an image color-printed on paper is input as digital color image data, and whether the input image is in a paper color area or in another area is determined. The discrimination is performed based on the image feature amount, and the show-through reduction processing suitable for each is performed based on the discrimination result, thereby reducing the show-through occurring in both the paper surface color and the other area. In the image processing method according to the ninth aspect of the present invention, an image color-printed on a paper is input as digital color image data, and whether the input image is in a paper color area or another area is determined. Discrimination based on image features such as brightness, saturation, edge strength, and hue, and applying the appropriate show-through reduction processing based on the discrimination results, reduces the show-through that occurs in both the paper color and other areas. It is characterized in that it is made to be. Further, the recording medium of the invention according to claim 10 is executed by a computer, and an image input function for inputting an image color-printed on paper as digital color image data to the computer; A region discriminating function for discriminating whether a region is located in a region or a region other than the region based on an image feature amount, and a reduction processing function for reducing show-through occurring in both the paper surface color and the other region based on a result of the determination. The program for realizing was recorded.

[0007] The recording medium according to the eleventh aspect of the present invention is executed by a computer, and is stored in the computer.
An image input function for inputting an image color-printed on paper as digital color image data, and determining whether the input image is in a paper color area or other area by brightness, saturation, edge strength, and hue. An area discriminating function for discriminating based on the image feature amount of the image, and a reduction processing function for reducing show-through occurring in both the paper surface color and the other areas by performing a show-through reduction process suitable for each of the discrimination results. The program for realizing was recorded. An image forming apparatus according to a twelfth aspect of the present invention is an image forming apparatus, comprising: an image input unit for inputting an image color-printed on paper as digital color image data; Area reduction unit that determines whether or not there is an image feature amount, a reduction processing unit that reduces show-through that has occurred in both the paper color and other areas based on the determination result, and a pixel that has undergone this reduction processing. And an image output unit for outputting image data subjected to halftone processing or the like. According to a thirteenth aspect of the present invention, there is provided an image forming apparatus, comprising: an image input unit for inputting an image color-printed on paper as digital color image data; And an area discriminating unit for discriminating whether the image is present in the image based on brightness, saturation, edge strength, and hue. The image processing apparatus further includes a reduction processing unit configured to reduce show-through generated in the area, and an image output unit configured to output image data obtained by performing halftone processing or the like on the pixels subjected to the reduction processing.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. (1) Approach to show-through processing according to the present invention The scenes in which show-through processing is actually used include incorporation into a digital color copying machine, application software for a scanner, digital camera, and color document image analysis / recognition system. A situation / environment such as processing is assumed. Considering such various situations and environments,
In the present invention, the following approach has been studied to deal with the problem of show-through of a color image. First, in order to solve the problems of the conventional technology, it is necessary to distinguish the image on the front side of the document from the other. A printing device such as a laser printer uses a special halftone pattern such as a halftone dot or a line pattern in order to express a halftone from the characteristics of a pigment or a dye. Therefore, even if these prints are macroscopically uniform regions, dots formed of pigments and dyes are visible when enlarged and microscopically viewed. As digital image processing devices such as copiers and scanners have become more sophisticated, the resolution of those devices has been improved, so halftone dots and line patterns can be seen in images captured at a resolution of about 600 dpi. The difference in the appearance of micro and macro colors becomes a problem. Conversely, when an image is captured at a high resolution, the pigments and dyes that make up the printed portion will be visible, so the difference in the degree of saturation between the printed portion and the paper surface will be greater than the macro appearance. Therefore, since the show-through component is seen through a white paper surface, the wavelength component is the same as that in which white noise is added, and the saturation of the show-through area does not exceed a certain value depending on the paper quality. . Further, when edges are extracted from an image at a resolution higher than that at which dots constituting halftone dots can be seen, edges resulting from the dots in the image on the surface are also extracted. Further, to hold the halftone area means to hold the dots forming the halftone pattern. Conversely, when the dots are held, the color appearance in the macro is held.

For the reasons described above, the degree of saturation of the show-through area,
Since there is a large difference in the degree of saturation between the dots constituting the surface image, the effectiveness of the threshold processing is higher in a high-resolution image than in a low-resolution image in which halftone dots are smoothed. Therefore, the condition that the saturation level is larger than the specific threshold value TH1 can be used as a condition for specifying the front image highlight area expressed in the halftone. This threshold TH1
Has a correlation with the transmittance of the paper and depends on an image input device such as a scanner. Therefore, a representative paper type is statistically obtained in advance for each image input device. In addition, since TH1 separates the image of the front surface from the other, it may be set as the parameter of the applicable range of the show-through reduction process and set on the user side. Further, low-luminance pixels are extracted from the high-resolution image, and a certain threshold T
The fact that the luminance is lower than H2 may be used as a condition for specifying the image highlight area on the surface expressed in the halftone. This threshold value TH2 is obtained in advance similarly to the threshold value TH1. Furthermore, the halftone processing is performed by determining that the edge amount (edge strength) caused by the halftone pattern obtained by extracting the edge from the high-resolution image is larger than a certain threshold TH3. A condition for specifying the image highlight area on the front surface can also be used. For this edge extraction, for example, Laplacian may be used. This threshold value TH3 is obtained in advance similarly to the threshold value TH1.

(2) Functional Configuration and Operation of Image Forming Apparatus of One Embodiment of the Present Invention Hereinafter, the configuration and operation of the embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram illustrating functions of an image forming apparatus according to an embodiment of the present invention. That is, the image forming apparatus according to the embodiment includes the image input unit 10, the area determination unit 20, the reduction processing unit 40, the parameter setting unit 30, the image processing unit 50, and the image output unit 60. The image input unit 10 inputs an image from a digital color copying machine or a scanner, performs A / D conversion processing, and temporarily stores the image in a memory or the like. Further, image data may be received from application software of a digital camera or a color document image analysis / recognition system.
The area determination unit 20 converts each pixel of the image data temporarily stored in a memory (not shown) into a hue, saturation, and brightness color space (HSV color space), and the pixel is present in the print area. Is determined. For this color space conversion,
General well-known conversion formulas, for example, Color Technology For
This is performed using the method described in Electronic Imaging Devices (HRKang: 1997). This determination, as described by the above approach, specifies that the target pixel satisfies one of the following three conditions as a highlight area (that is, a print area). (Condition 1) When the degree of saturation is greater than a certain threshold value TH1. (Condition 2) A case where low-luminance pixels are extracted from a high-resolution image and the luminance is lower than a specific threshold TH2. (Condition 3) A case where an edge amount (edge strength) caused by a halftone pattern obtained by extracting an edge from a high-resolution image is larger than a certain threshold value TH3. These threshold values TH1, TH2, and TH3 are correlated with the transmittance of the paper and depend on the image input device such as a scanner. Calculate statistically.

The parameter setting unit 30 includes three threshold values TH1, TH2, and TH used in the area discriminating unit 20.
3 is determined in advance, and the user designates it as an adaptation range parameter of the show-through reduction processing from an input device such as a keyboard. The reduction processing unit 40 determines, for example, an area determined as a highlight area (print area) by the area determination unit 20, for example, Japanese Patent Application No. 11-35 filed by the present applicant.
4412 is used to reduce show-through. In addition, for a portion determined not to be a highlight area, the following background removal processing is performed. For a document printed on both sides, the content of the image on the back side cannot be specified, so that the area determined as the document paper area is simply multiplied by a specific weighting coefficient to the pixel value to improve the brightness, and the paper area is Makes appearing images inconspicuous. At this time, by calculating the luminance from the original pixel value and changing the weighting coefficient according to the luminance, it is possible to prevent the occurrence of a pseudo edge between the printed portion and the rest. If the output device cannot output a very thin highlight area, all the pixels determined to be the paper area may be replaced with white to reduce the amount of calculation instead of the above weighting processing. Further, by storing in advance color information such as newspaper color or hue information such as a marker added to an original, a corresponding area can be protected. As a result, in the case of an extremely thin marker, it may be erroneously determined to be show-through, which can be avoided. Conversely, by allowing the user to select a hue using input means (not shown), it is possible to selectively delete only a specific marker. The image processing unit 50 performs image processing such as removal of isolated points, color correction, and area identification for moire reduction on the image data obtained as a result of the processing by the reduction processing unit 40, so as to be compatible with each image output device. Is converted to The image output unit 60 outputs the data processed by the image processing unit 50 to an image output device.

FIG. 2 is a flowchart for explaining the operation of the image forming apparatus according to one embodiment of the present invention. First, an image is input from an image input device such as a digital color copying machine or a scanner, and A / D conversion processing is performed, and the image is temporarily stored in a memory or the like (step S10). Each pixel of the image data temporarily stored in the memory is converted into a hue, saturation, and brightness color space (HSV color space), and it is determined whether the pixel is in a print area (step S).
20). In this determination, when the target pixel satisfies any of the following three conditions, it is determined that the pixel is in the highlight area (that is, the print area). (Condition 1) When the degree of saturation is greater than a certain threshold value TH1. (Condition 2) A case where low-luminance pixels are extracted from a high-resolution image and the luminance is lower than a specific threshold TH2. (Condition 3) A case where an edge amount (edge strength) caused by a halftone pattern obtained by extracting an edge from a high-resolution image is larger than a certain threshold value TH3. These threshold values TH1, TH2, and TH3 may be obtained in advance and stored in a memory or the like, or may be specified by a user as a parameter from an input device such as a keyboard. Furthermore, if hue information such as a paper color of a newspaper or a marker added to a manuscript is held in advance, the hue information is compared with the hue information of the target pixel,
If they are the same, it can be determined that the area is a paper color area. In this manner, the present invention can be applied to a case where the paper surface color is not white or an area written with a marker.

The show-through reduction processing is performed for each pixel in the area specified by the above determination (step S3).
0). For an area determined to be a highlight area (print area), show-through reduction processing is performed using, for example, the method of Japanese Patent Application No. 11-354412. In addition, for a pixel determined to be not in the highlight area, the weighting coefficient is adjusted according to the luminance of the pixel to multiply the pixel value to improve the luminance, thereby making the image appearing in the paper area inconspicuous. If the output device cannot output an extremely thin highlight area, the weight may be replaced with white instead of the weighting process. Here, if the area determined as the paper color or the marker area based on the hue information is replaced with the pixel value of the paper color, the background removal processing can be performed even if the area is not a white background area. In addition, by allowing the user to select a hue, a highlight region by a marker can be selectively removed. The image data resulting from the show-through reduction processing is subjected to image processing such as removal of isolated points, color correction, and area identification for moiré reduction, and is converted to be compatible with each image output device (step S).
40). The image-processed data is output to the image output device (step S50).

(3) Processing Procedure of Reduction Processing FIG. 3 is a flowchart for explaining the show-through reduction processing. The first pixel data of the input pixel data (see FIG. 4) is extracted (step S110). For example, the pixel at the head (1, 1) of the scanned image data is extracted (here, the pixel at the i-th row and the j-th column is represented by (i, j)). Pixels represented in the RGB color space (other color spaces may be used as long as the color space is interchangeable with the RGB color space) is converted to the HSV color space, and the hue and saturation S (i, j) are converted. ) And brightness V (i, j) are calculated (step S120).
It is determined whether or not the saturation S (i, j) is a pixel satisfying the above condition 1 (step S130). Saturation degree S
If (i, j) is larger than the threshold value TH1, step S1
Proceed to 70. Otherwise, it is determined whether the brightness V (i, j) is a pixel satisfying the above condition 2 (step S1).
40). If the brightness V (i, j) is smaller than the threshold value TH2, the process proceeds to step S170. Otherwise, the position of this pixel is defined as (x, y), and the edge intensity E (i, j) at (x, y) in the input image is calculated by, for example, Laplacian, and the edge intensity E (i , J) to determine whether Condition 3 is satisfied (Step S1).
50). When the edge strength E (i, j) is larger than the threshold value TH3, the process proceeds to step S170. Otherwise, it is apparently set as a pixel in the original paper area, and this pixel is subjected to show-through removal processing for a white background (step S160), and the process proceeds to step S180. In the background removal processing, the weighting coefficient is changed according to the luminance of the pixel, the luminance is improved by multiplying the pixel value, and the image appearing in the paper area is made inconspicuous. As a result, it is possible to prevent the occurrence of a pseudo edge between the printed portion and the other portion.

If the output device cannot output an extremely thin highlight area, all the pixels determined to be the paper area are replaced with white instead of the above weighting processing to reduce the amount of calculation. Is also good. Further, in the case of output to an output device having a high reproducibility of a highlight area such as a CRT, for example, the pixel value may be converted by the following equation.
This can suppress generation of an unnatural edge between the print area on the front surface and the other area. here,
The brightness V of the input pixel value is in the range of 0 to 255,
Is black, and the brightness increases as the numerical value increases.
Further, it is assumed that the saturation S is in the range of 0 to 255, and 0 is achromatic and becomes closer to a pure color as it becomes larger. Then, the output lightness Vout can be calculated from the lightness V of the input pixel by the following conversion formula. 1) When S <TH1 Vout = V (when V ≦ a) Vout = {(255−a) / (ba)} * V + (b−255) * a (when a <V <b) Vout = 255 (when V ≧ b) In the above equation, a may be set to the threshold value TH2. 2) When S ≧ TH1 Vout = V Here, a and b indicate a modulation range of the luminance of the input pixel, and a pixel having an input luminance larger than a and smaller than b is
The output changes sharply with respect to the input. For example, FIG. 4 shows a function of a simple example in which all white pixel values (255) are set when the luminance of an input pixel is equal to or higher than a certain value. FIG. 5 shows a graph of a function cut out when the degree of saturation in FIG. 4 is zero.

FIG. 6 shows that the luminance of the input pixel is larger than a (a = 180 in this figure) and b (b = 23 in this figure).
0), Vout = 1.5 V-90 so that the relationship between the input and output becomes steep, and when the luminance of the input pixel is b or more, all are set to the white pixel value (255). FIG. 7 shows a graph of a function extracted from the case where the degree of saturation in FIG. 6 is zero. In step S170, a pixel that satisfies one of the conditions 1, 2, and 3 is regarded as being in the print area, a show-through reduction process for the highlight area is performed, and the process proceeds to step S180. This mitigation process is performed by setting a local window of an appropriate size, centering on the target pixel, and using the technique of Japanese Patent Application No. 11-354412 for the window. You. Step 180
Then, it is determined whether the processing has been completed for all the pixels of the input image. If the processing has been completed for all the pixels, the reduction processing ends. If the processing has not been completed, the next target pixel of the input image data is extracted (step S190), and the processing is repeated from step S120.

FIG. 9 shows pixels satisfying the conditions 1 to 3 in the image data of FIG. 8 in black.
A halftone show-through reduction process is performed on this black area, and a show-through removal process for a white background is performed on pixels represented by white. As a result, the output is as shown in FIG. The calculation amount can be reduced by narrowing down the conditions as described above as compared with the case where each condition is calculated for all the pixels of the input image. By configuring the present embodiment as described above, the following effects can be achieved. -The show-through in both the highlight area and the paper area can be reduced. It is possible to selectively remove show-through on a white background, which is likely to occur when a document printed on both sides of a white paper is converted into digital data using a scanner or the like. It is possible to remove show-through having a lower luminance than the highlight area in the original front image, and to retain the highlight area expressed in halftone. Further, the present invention can be applied to a highlight region of a specific hue, such as a newspaper color or a marker, which is not expressed in a halftone. By performing color space conversion calculation first and calculating edge strength only for pixels that satisfy the conditions for saturation and lightness,
The amount of calculation can be reduced. (However, if the calculation amount of the edge strength is smaller than the color space conversion, the edge extraction may be performed first.)

(4) Realization by Computer FIG. 11 is a hardware configuration diagram for configuring an image forming apparatus according to an embodiment of the present invention using a computer. In the present embodiment, a color image input from the image input device 1 such as a scanner or a digital camera is stored in the memory 6. Further, the processing function of the above-described color image processing apparatus is the same as that of the RO holding the program for realizing the processing function.
M (Read Only Memory) 7 to CPU (Central Processes)
sing unit) 5 is executed by reading the program. The progress and the results during the processing are presented to the user through the display device 2 such as a display, and when necessary, the user inputs and specifies parameters necessary for the processing from the input device 3 such as a keyboard or a touch panel. Further, the intermediate data created during the image processing is stored in the memory 6 and read, corrected and written by the CPU 5 as necessary. The show-through removed image generated as a result of the series of processing is read from the memory 6 and output to the image output device (such as a printer) 4. Further, a server computer that holds a program for realizing the image processing function of the present invention in a storage device such as a magnetic disk and a user terminal (a computer or an image forming apparatus such as a printer or a copying machine may be used). ) Can be connected to a network and distributed from the terminal in the form of download or the like, or can be distributed from the server to the terminal.

[0019]

As described above, according to the present invention,
Since the image on the front side of the document can be distinguished from the image due to the other part, it is possible to perform the show-through reduction process suitable for each.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a functional configuration according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of processing according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating a show-through reduction process according to the present invention.

FIG. 4 is a diagram illustrating a luminance modulation function of output luminance with respect to input luminance.

FIG. 5 is a diagram extracted from the graph of FIG. 4 when the degree of saturation is zero.

FIG. 6 is a diagram illustrating a luminance modulation function of output luminance with respect to input luminance.

7 is a diagram extracted from the graph of FIG. 6 when the saturation is zero.

FIG. 8 is a diagram showing an example in which show-through exists in both a halftone area and a white background area.

FIG. 9 is a diagram showing an example in which pixels satisfying conditions 1 to 3 are displayed in black.

FIG. 10 is a diagram illustrating an output example in which show-through in both a halftone area and a white background area is reduced.

FIG. 11 is a hardware configuration diagram for realizing an image forming apparatus according to an embodiment of the present invention.

[Description of Signs] 10 image input unit 20 area discriminating unit 30 parameter setting unit 40 reduction processing unit 50 image processing unit 60 image output unit 1 image input device 2 ... Display device 3 Input processing 4 Image output device 5 CPU 6 Memory 7 ROM 8 Data bus

Claims (13)

[Claims] 1. An image input unit for inputting an image color-printed on paper as digital color image data, and determining whether the input image is in a paper color area or another area by an image feature amount. An area determining unit for determining,
An image processing apparatus comprising: a reduction processing unit that performs a show-through reduction process suitable for each of the determination results, and reduces show-through occurring in both the paper color and the other area. 2. The image processing apparatus according to claim 1, wherein the image characteristic amount of the area determination unit includes brightness, saturation,
An image processing device using edge strength. 3. The image processing apparatus according to claim 2, wherein the area determination unit compares the hue information of a specific paper color and the hue information of an input image to determine that the area is a paper color area. An image processing apparatus comprising: 4. The image processing apparatus according to claim 2, wherein the area determination unit determines whether or not the area is a paper color area based on hue information of a specific paper color and hue information of an input image. The reduction processing unit removes the area when it is determined that the area is the paper color, or
An image processing apparatus characterized in that it is possible to instruct whether to leave. 5. The image processing apparatus according to claim 1, wherein the reduction processing unit determines whether the area is determined to be an area other than a paper color by the area determination unit. An image processing apparatus characterized in that a reduction process is performed using only the information of the image processing apparatus. 6. An image input unit for inputting an image color-printed on paper as digital color image data, and determining whether the input image is in a paper color area or other area by brightness and saturation. A region discriminating unit for discriminating based on the image feature amount of the edge strength and the hue, and performing a show-through reduction process suitable for each according to the discrimination result by the region discriminating unit to apply both to the paper surface color and the other region. An image processing apparatus comprising: a reduction processing unit configured to reduce generated show-through. 7. The image processing apparatus according to claim 6, wherein the reduction processing unit performs processing using only information inside a local window when the area determination unit determines that the area is not a paper color. An image processing apparatus characterized by performing: 8. An image color-printed on paper is input as digital color image data, and it is determined whether the input image is in a paper color area or in an area other than the paper color area based on an image feature amount. An image processing method characterized by reducing show-through occurring in both the paper surface color and the other area by performing a show-through reduction process suitable for each of the determination results. 9. An image color-printed on paper is input as digital color image data, and whether the input image is in a paper color area or a non-color area is determined by brightness, saturation, edge intensity, and the like. The feature is that it is determined based on the image feature amount of the hue, and the show-through reduction processing suitable for each is performed to reduce the show-through generated in both the paper surface color and the other area based on the determination result. Image processing method. 10. An image input function which is executed by a computer and inputs an image printed in color on paper as digital color image data to the computer.
An area discriminating function for discriminating whether the input image is in the paper color area or the other area based on the image feature amount, and a back surface generated in both the paper color and other areas is determined based on a result of the discrimination. A computer-readable recording medium on which a program for realizing a reduction processing function for reducing reflection is recorded. 11. An image input function which is executed by a computer and inputs an image printed in color on paper as digital color image data to the computer.
An area discriminating function for discriminating whether the input image is in a paper color area or a non-paper area based on image feature amounts of lightness, saturation, edge intensity, and hue, and a result of the discrimination, which is suitable for each. A computer-readable recording medium storing a program for realizing a reduction processing function for reducing show-through occurring in both the color of the paper and other areas by performing the show-through reduction processing. 12. An image input unit for inputting an image color-printed on paper as digital color image data, and determining whether the input image is in a paper color area or in another area by an image feature amount. An area discriminating section for discriminating, a reduction processing section for reducing show-through generated in both the paper color and other areas based on the discrimination result, and a halftone process or the like is performed on the pixel subjected to the reduction processing. An image forming apparatus comprising: an image output unit that outputs image data. 13. An image input unit for inputting an image color-printed on paper as digital color image data, and determining whether the input image is in a paper color area or in other areas by brightness and saturation. , An area discriminating unit that discriminates based on the image feature amount of edge strength and hue, and, based on the discrimination result, reduces the show-through that occurs in both the paper color and the other areas by performing an appropriate show-through reduction process An image forming apparatus comprising: a reduction processing unit that performs a reduction process; and an image output unit that outputs image data obtained by performing a halftone process or the like on the pixel subjected to the reduction process.