Image processing apparatus, control method for image processing apparatus, and storage medium

An image processing apparatus processes image data generated by a reading unit configured to read a document, using at least one of a plurality of types of reading elements that have different spectral sensitivity characteristics and are cyclically arrayed in a first direction, by scanning the document in a second direction vertical to the first direction. The image processing apparatus includes a processing unit configured to perform, on the image data, filter processing for averaging pixel values of pixels at least equal in number to the types of the reading elements in the first direction, wherein the processing unit is implemented by at least one processor or at least one circuit.

BACKGROUND

Field

The present disclosure relates to an image processing apparatus that processes image data read from an original document, a control method for an image processing apparatus, and a storage medium.

Description of the Related Art

A copier and a multifunction printer includes an image reader for reading an image from an original document. Examples of a conventionally known image reader include one that includes a contact image sensor (CIS) that directly reads an image using a linear sensor via a Selfoc (registered trademark) lens.

Among such image readers, a type widely in use has a configuration in which a plurality of linear sensors having respective lengths thereof extending in a certain direction are arranged side by side in parallel, so that such a type of image reader reads an original document by these linear sensors physically scanning the original document in a direction perpendicular to the lengths of the linear sensors. Within each of the linear sensors, a plurality of photosensitive elements (light receiving elements) that have the same spectral sensitivity are arrayed. The plurality of linear sensors intended to read different colors such as red, green, and blue is configured to include corresponding color filters applied over light receiving surfaces. The sensors consequently have respectively different spectral sensitivities. An image is read by each of the linear sensors, and photoelectrically converted into signals. Signal values thus obtained are combined with coordinates at which the image has been read, and then read-image data is generated. In the combining process, the signal values of the sensors having different spectral sensitivities are treated as signal values that correspond to one set of coordinates. Thus, color image data can be generated.

There is also known a type of image reader in which, instead of a plurality of line sensors each having the spectral sensitivity for the same color arranged side by side in parallel, a plurality of line sensors in each of which photosensitive elements having different spectral sensitivities are arrayed are arranged side by side in parallel. Such an image reader reads an image by causing these line sensors to scan the image.

Yet another known type of image reader includes, instead of line sensors, an area sensor (for example, a charge-coupled device (CCD) image sensor with the Bayer pattern) in which photosensitive elements having different spectral sensitivities are two-dimensionally arrayed. Such an image reader reads an image by causing the area sensor to scan the image.

In such an image reader, instead of a monochromatic line sensor in which photosensitive elements having the same spectral characteristic are arrayed in the direction vertical to the sensor scanning direction, photosensitive elements having different spectral characteristics are arrayed in a specific pattern, which enables reading with even higher density, speed, and accuracy.

However, deterioration in image quality may occur in edge portions of an object such as a character or a line on an original document due to an optical error of the sensor and an error in driving of the sensor for scanning during image reading, or shaking of the image reader caused by an external factor.

FIG. 8illustrates examples of deterioration in image quality (cyclic unevenness and color shift).

InFIG. 8, image data800illustrates deterioration in image quality that occurs in an edge portion of a monochrome line when a monochrome gray image is generated by reading using only a sensor for green among those for red, green, and blue. In this example, the edge portion of the monochrome line is not uniformly aligned, and cyclic unevenness (irregularities) occur.

Image data801illustrates deterioration in image quality that occurs in an edge portion of a monochrome line when a color image is generated by reading using sensors for three colors of red, green, and blue. In this example, the red, green, and blue colors are not uniformly distributed in the edge portion of the monochrome line, and a color shift cyclically occurs.

Furthermore, the occurrence of such a color shift not only causes deterioration in image quality but also raises another issue. Some image readers employ an image processing technique called Auto Color Select (ACS). This technique determines whether an original document read by the image reader is printed in color or only in monochrome. This ACS, however, may determine an area in which the color shift has occurred as a continuous area composed of color pixels and thus erroneously determine a monochrome original document as a color document.

Techniques for overcoming these issues include a technique for correcting the color shift after determining whether correction needs to be performed on the read image (Japanese Patent Application Laid-Open No. 2017-208602) and a technique in the ACS is executed after correcting the color shift (Japanese Patent Application Laid-Open No. 2011-259427).

If a position and an amount of deterioration in image quality, typically caused by the occurrence of cyclic unevenness and color shift as in the above-described examples, have been identified in advance as known characteristics of an image reader, the ACS can be correctly performed by correcting the deterioration in image quality and/or excluding the identified position from positions used for ACS determination.

SUMMARY

It has now been determined that causes of deterioration in image quality include not only reproducible causes resulting from known factors but also causes resulting from shaking of an image reader due to an external factor and unreproducible shaking due to an original document or driving of a sensor. Deterioration in image quality due to such unexpected causes cannot be improved by conventional techniques.

In conventional techniques, if a position and an amount of deterioration in image quality can be determined from read image data, the ACS can be correctly performed by correcting the deterioration in image quality and/or by excluding the determined position from positions used as references for ACS determination. However, it is difficult to make a distinction between a content originally contained in an original document and a phenomenon generated as a result of deterioration in age quality. Therefore, a correct content of the original document may be corrected excessively as a result of erroneous determination.

As described above, the conventional techniques have an issue that, on such a read image that has been deteriorated in its image quality, correction that is effective in improving the image quality or accurate ACS may not be executed.

Based on the above-discussed considerations, in accordance with an aspect of the present disclosure, an image processing apparatus processes image data generated by a reading unit configured to read a document, using at least one of a plurality of types of reading elements that have different spectral sensitivity characteristics and are cyclically arrayed in a first direction, by scanning the document in a second direction vertical to the first direction. The image processing apparatus includes a processing unit configured to perform, on the image data, filter processing for averaging pixel values of pixels at least equal in number to the types of the reading elements in the first direction, wherein the processing unit is implemented by at least one processor or at least one circuit.

DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments for carrying out the aspects of the present disclosure are described below with reference to the accompanying drawings. Configurations provided in the following exemplary embodiments are merely examples, and the scope of the present disclosure shall not be limited to configurations illustrated in the drawings.

A first exemplary embodiment is described below. The present exemplary embodiment will be described using an example of a configuration in which a gray image of 600 dpi is generated using only photosensitive elements (light receiving elements or reading elements) having the same specific spectral characteristic in a sensor that includes photosensitive elements having different spectral sensitivity characteristics arrayed in specific patterns. An alternative configuration for generating a gray image may be employed in which the gray image is generated by blending colors after color images are generated. However, the configuration according to the present exemplary embodiment is characterized by generating a gray image in a simpler manner and at higher speed than the alternative configuration in which colors are blended.

FIG. 1is a diagram illustrating an example of the configuration of an image processing apparatus according to an exemplary embodiment of the present disclosure. In the configuration of the image processing apparatus according to the present exemplary embodiment, after a monochrome gray image is generating by reading an original document, improvement processing for improving image quality is executed on the generated image.

As illustrated inFIG. 1, an image processing apparatus100according to the present exemplary embodiment includes a main control unit110, a storage unit120, an operation unit130, a reading unit101, and a filter processing unit102.

The main control unit110controls the entirety of the image processing apparatus100. The main control unit110is, for example, a controller and includes a central processing unit (CPU)110aand a nonvolatile memory110b. The CPU110aimplements various kinds of control by executing computer programs stored in the nonvolatile memory110b.

The storage unit120stores therein image data, information associated with the image data, and the like. The storage unit120is, for example, configured of a dynamic random access memory (DRAM).

The operation unit130receives instructions from an operator and displays information for the operator. The operation unit130is, for example, an operation touch panel user interface.

The reading unit101includes a sensor300illustrated inFIG. 3, which will be described below. The reading unit101reads an original document using the sensor300to generate image data.

The filter processing unit102performs filter processing on an image. The filter processing will be described below.

FIGS. 2A and 2Bare flowcharts illustrating examples of operations of the image processing apparatus100according to the present exemplary embodiment.FIG. 2Aillustrates the overall operation in the present exemplary embodiment.FIG. 2Billustrates details of the filter processing in the present exemplary embodiment. The processing in each of the flowcharts illustrated inFIGS. 2A and 2Bis implemented by the CPU110ain the main control unit110when the CPU110areads a program stored in the nonvolatile memory110band executes the read program. The processing inFIG. 2Ais started by the main control unit110upon receiving, via the operation unit130, an operation performed by the operator to start reading.

In step S201, under the control of the main control unit110, the reading unit101reads an original document to generate image data, and stores the generated image data in the storage unit120. In the subsequent processing, this image data serves as target data on which image processing is performed.

The configuration of the sensor300in the reading unit101will be described.

FIG. 3schematically illustrates the sensor300in the reading unit101.

InFIG. 3, a direction302is a direction (scanning direction) in which the sensor300performs scanning. A direction301is a direction vertical to the direction302.

In the sensor300, photosensitive elements that acquire red, green, and blue luminance signals are arrayed in specific patterns in the respective directions302and301.

In other words, in the direction301, the photosensitive elements are arrayed in order of red, green, and blue in a repetitive manner.

In the direction302, three photosensitive elements are arrayed in order of red, blue, and green, order of green, red, and blue, or order of blue, green, and red. That is, in the sensor300, the photosensitive elements are arrayed in the direction302in a repetitive manner in the minimum unit of three photosensitive elements. In the present exemplary embodiment, the sensor300thus configured is used to read a document using only the green photosensitive elements.

That is, the reading unit101includes the sensor300in which a plurality of kinds of reading elements (photosensitive elements for red, green, and blue) that have different spectral sensitivity characteristics are cyclically arrayed in the direction301. The reading unit101reads an original document by scanning the original document in the direction302using at least one (green in the above-described example) of the plurality of kinds of photosensitive elements and generates image data.

First, ideal image reading will be described.

FIG. 4illustrates ideal image reading.FIG. 4illustrates reading of a monochrome gray image in an ideal state, that is, in a state where no deterioration in image quality has occurred. The identical reference numerals are assigned to components that are identical to those inFIG. 3.

An original document410has an image printed thereon that has a black object on a white background.

When the image is read with the sensor300scanning the original document410in the direction302, for example, luminance signals of 8 bits as indicated in tables420,421, and422are acquired. The table420of luminance signals is generated using the fact that respective sets of acquisition coordinates (x, y) of the green photosensitive elements arrayed in the sensor300are different from one another at an acquisition time t.

For example, sensor positions411,412, and413are defined as positions of the sensor300at times t=0, 1, and 2, respectively. A luminance signal value acquired at the time t by the sensor300at the sensor position expressed by coordinates (X, Y) is defined as a luminance signal value L(X, Y, t). Accordingly, a green signal value corresponding to coordinates (x, y)=(0, 2) on the original document410is acquired as a luminance signal value L(0, 2, 0) (corresponding to a value for y=2 in the table420). Similarly, a green signal value corresponding to coordinates (x, y)=(1, 2) on the original document410is acquired as a luminance signal value L(1, 0, 2) (corresponding to a value for y=2 in the table421). A green signal value corresponding to coordinates (x, y)=(2, 2) is acquired as L(2, 1, 1) (corresponding to a value for y=2 in the table422). Green signals for the respective pixels are reconstructed, so that image data430ofFIG. 4is obtained as digital image data into which the original document410has been correctly reproduced.

Next, a case of image reading in which deterioration in image quality has occurred will be described.

FIG. 5illustrates reading of a monochrome gray image in which cyclic unevenness has occurred. The identical reference numerals are assigned to components identical to those inFIGS. 3 and 4.

As described inFIG. 4, the original document410has an image printed thereon that has a black object on a white background.

When the image is read by the sensor300scanning the original document410in the direction302, for example, luminance signals of 8 bits as illustrated in tables520,521, and523are acquired.

Here, it is assumed that, at the time t=2, the sensor300that is supposed to be at the sensor position513is shifted upward in the direction302to a position the same as the sensor position512at the time t=1. At this time, in a column for x=0, the photosensitive element for green in the sensor300reads a signal value (255) at a white pixel517, i.e., at coordinates (x, y)=(0, 3) although the green photosensitive element is supposed to read a signal value (0) at a black pixel516, i.e., at coordinates (x, y)=(0, 4).

For example, in a column for x=1, the sensor300reads a signal value (0) at a black pixel518, i.e., at coordinates (x, y)=(1, 4), at the time (t=4) when the sensor300is correctly positioned at a position515.

As a result, as compared with the table521where the x-coordinate value is one (x=1) and the table522where the x-coordinate value is two (x=2), the luminance signal of the sensor300obtained when the x-coordinate value is zero (x=0) extends downward by one pixel in the direction302as in the table520. That is, unevenness (deterioration in image quality) occurs in three-pixel cycles at an edge portion of the black object on the original document410. Digital image data acquired under such a condition is image data530ofFIG. 5.

Pixels at the coordinates (x, y)=(0, 4) in the table520, the coordinates (x, y)=(3, 4) in the table521, and the coordinates (x, y)=(6, 4) in the table522, respectively, correspond to pixels531,532, and533in the digital image data530ofFIG. 5. In other words, from the case illustrated inFIG. 5, it can be understood that unevenness has occurred in three-pixel cycles at the edge portion.

For the sake of simplified explanation, a case in which an image containing only black pixels and white pixels is read without any blurring has been described with reference toFIG. 5. The amount of the shift of the sensor position that can cause deterioration in image quality has been described to be exactly one pixel in the foregoing case. The period for which the shift of the sensor position occurs is also limited to a certain one-frame period.

In reality, however, blurring due to printing characteristics depending on an original document and/or blurring due to characteristics associated with an optical system in the reading unit exit at the edge portion, i.e., the boundary between the black pixels and white pixels. The amount of the shift of the sensor position is not necessarily limited to exactly one pixel and may exceed one pixel or be less than one pixel. Furthermore, the period for which the shift of the sensor position occurs is not necessarily limited to a one-frame period, and the shift of the sensor position occurs over a plurality of frames in most cases.

Image data that has been obtained by reading the original document410in such a case and in which deterioration in image quality has occurred as a result is illustrated as image data600inFIG. 6.

FIG. 6is a diagram illustrating image data in which deterioration in image quality has occurred and effects of filter processing. The identical reference numerals are assigned to components that are identical to those inFIG. 5.

InFIG. 6, the image data600is image data generated by reading the original document410under a condition where such deterioration in image quality may occur. Numerical values provided in respective pixels in the image data600indicate luminance signals of 8 bits. The higher numerical value represents a whiter pixel, whereas the lower numerical value represents a blacker pixel. That is, focusing on the sensor scanning direction302in the image data600, it can be understood that blurring of about 3 pixels has occurred due to the printing quality of the original document and the accuracy of the read sensor. In the direction301vertical to the direction302in the image data600, meanwhile, it can be understood that shading has occurred in three-pixel cycles as a result of a positional shift of the sensor.

The description returns to the flowchart inFIG. 2A.

Upon completion of the processing in step S201, the processing proceeds to step S202.

In step S202, under the control of the main control unit110, the filter processing unit102performs filter processing by performing convolution on image data. Details of the filter processing is illustrated inFIG. 2B.

In processing of steps S203to S206inFIG. 2B, the main control unit110performs control such that the processing in steps S204and S205is repeatedly performed on all the pixels of the image read in step S201.

In step S204, under the control of the main control unit110, the filter processing unit102weights on a target pixel and neighboring pixels on the right and left of the target pixel. Filter coefficients are illustrated in 1×3 filter coefficient matrix610inFIG. 6. The filter coefficients in the filter coefficient matrix610are the filter coefficients of a filter for averaging a target pixel630and neighboring pixels on the right and left of the target pixel by equally weighting the three pixels. In other words, the filter coefficient matrix610is used to average pixels at least equal in number to the types of photosensitive elements in the vertical direction301in the image data generated by the reading unit101. In this case, three pixel values are averaged because three types of the photosensitive elements, i.e., red, green, and blue photosensitive elements, are used. The filter processing unit102performs processing in step S204using the filter coefficient matrix610.

Image data640is a part605cut out from the image data600. When the filter coefficient matrix610is applied to perform weighting on an image that has the pixel values as illustrated in the image data640, image data641is obtained as a result.

Subsequently, in step S205, under the control of the main control unit110, the filter processing unit102sums up the target pixel and neighboring pixels on the right and left sides thereof (i.e., values obtained as the results of the weighting in step S205) and determines the resultant value as a pixel value of the target pixel. The result value obtained by performing the summation on the image data641is a target pixel642.

Upon completion of the processing in step S205, the main control unit110performs control such that the processing in steps S204and S205is repeatedly performed on the subsequent pixels. Upon completion of the processing on all the pixels in the image data600, the filter processing inFIG. 2B(step S202inFIG. 2A) is ended.

A result obtained by convolutionally applying the filter coefficient matrix610to the image data600is image data601. In the image data601, the unevenness that appears in three-pixel cycles in the image data600is improved and smoothed by the averaging processing.

Upon completion of the processing in step S202, the processing inFIG. 2Ais ended.

The operation in the present exemplary embodiment has been described above.

As described above, according to the present exemplary embodiment, unevenness (deterioration in image quality) that occurs in three-pixel cycles can be improved by the filter processing that includes averaging pixel values. Since the cycle depends on the array pattern of the photosensitive elements, it is not limited to the three-pixel cycle. In a case where the cycle has a length of two pixels or four or more pixels, the same effect can be obtained by averaging based on the length. Thus, the image quality of image data read by scanning by a sensor that includes photosensitive elements having respectively different spectral characteristics arrayed in a specific pattern can be improved by a simple configuration. In particular, deterioration in image quality in edge portions can be prevented.

A second exemplary embodiment will be described below. In the first exemplary embodiment described above, image data on which the filter processing is performed contains not only a horizontal line edge as illustrated in the image data600inFIG. 6but also a vertical line edge as illustrated in image data602inFIG. 6. When the filter processing is performed on this image data602using the filter coefficient matrix610, image data603illustrated inFIG. 6is obtained. In the image data603, as compared with the image data602, the vertical line edge is averaged (smoothed) and consequently blurred. That is, the filter processing using the filter coefficient matrix610has an issue that an edge in a resultant image is blurred compared to an original image.

In the second exemplary embodiment, filter processing that is effective not only for a horizontal line edge but also for a vertical line edge.

In the second exemplary embodiment, a filter coefficient matrix611illustrated inFIG. 6is used. The 1×5 filter coefficient matrix611includes filter coefficients to be applied to pixels around a pixel631as a target pixel. The filter coefficient matrix611is obtained by convolutionally applying an edge enhancement filter matrix612to the filter coefficient matrix610. In this application, values to be applied to the both ends of the filter coefficient matrix611are set to 0.

A result obtained by performing filter processing using the filter coefficient matrix611on the image data600that contains the horizontal line edge is the image data601.

A result obtained by performing the filter processing using the filter coefficient matrix611on the image data600that contains the vertical line edge is image data604.

Through this filter processing, similar to the image data601in which unevenness at the horizontal line edge is improved, the image data604maintains the vertical line edge having almost the same level of sharpness as that of the original image. In other words, in the image data604generated using the filter coefficient matrix611, the issue at the vertical line edge has been resolved compared to the image data603generated using the filter coefficient matrix610in the first exemplary embodiment. This filter processing utilizes the difference between a frequency characteristic of the unevenness occurring in three-pixel cycles, which is about 8 lines/mm, and a frequency characteristic of the edge portion of an object such as a character or a line, which is about 3 to 5 lines/mm, in a read image of 600 dpi. In general, a document used as an original document has a frequency characteristic of about 3 to 5 lines/mm in most cases. For example, in the case of a kanji (or Chinese) character for “den (electricity)” in a Microsoft Ming font, which has a relatively high frequency among other characters in other fonts, the character in a 5-point Microsoft Ming font, that is in size close to the limit of readability, includes seven horizontal lines in a range of about 1.4 mm between the uppermost line and the lowermost line of the character, thus having a frequency characteristic of about 5 lines/mm. In reality, however, those characters that are larger than 5-point characters and have relatively low frequency components are used in most cases. Therefore, the frequency of an object such as a character or a line falls within 3 to 5 lines/mm while varying depending on the degree of blurring at edge portions.

As described above, in the present exemplary embodiment, filter processing is performed on read image data using the filter coefficient matrix611for smoothing unevenness due to deterioration in image quality using the elements of an averaging filter and for maintaining sharpness of edge components using an edge enhancement filter. The characteristic of the filter coefficient matrix611enables not only the unevenness to be improved in a horizontal line edge but also the sharpness of a vertical line edge to be maintained at almost the same level as in an original image.

A third exemplary embodiment will be described below. The present exemplary embodiment will be described using a configuration in which a color image of 600 dpi is generated using a sensor (for example, the sensor300illustrated inFIG. 3) in which photosensitive elements having different spectral characteristics are arrayed in a specific pattern.

In a case where a color image is read, the apparatus configuration of an image reader and a flowchart indicating the operation of the image reader are the same as those for reading a gray scale image in the first and the second exemplary embodiments. A difference from the first and the second exemplary embodiments is that, as described below, image reading and filter processing are for each color of red, green, and blue, not for a single color. Detailed description is given below with reference toFIGS. 2A, 2B, and7.

In the third exemplary embodiment, in step S201inFIG. 2A, the reading unit101reads an original document to generate full-color (red, green, and blue) image data and stores the generated image data in the storage unit120under the control of the main control unit110. Specifically, red image data, green image data, and blue image data are stored in the storage unit120.

FIG. 7illustrates an image in which a color shift has occurred and effects of filter processing according to the third exemplary embodiment.

InFIG. 7, pieces of image data700,701, and702are red image data, green image data, and blue image data, respectively, generated by reading the original document410in the first exemplary embodiment, i.e., an image containing a black object on a white background.

The image data701indicates luminance signals read by the green photosensitive elements and is accordingly the same as the image data600illustrated inFIG. 6.

The image data700indicates luminance signals read by the red photosensitive elements. The image data702indicates luminance signals read by the blue photosensitive elements. The pieces of image data700and702are acquired under the conditions same as those when the image data701is acquired, except that the arrays of the photosensitive elements differ in phase. Accordingly, the image data700and702correspond to images obtained by shifting the phase of the image data600. That is, in all of the image data700to702, the same unevenness (deterioration in image quality) has occurred in phases respectively different by the colors.

The image data703schematically represents color image data obtained by combining the image data700(red),701(green), and702(blue).

In the image data703, “W” indicates a white pixel, and “Bk” indicates a black pixel. “R” indicates a pixel that is slightly more reddish than a pure gray color, “G” a pixel that is slightly more greenish than the pure gray color, and “B” a pixel that is slightly more bluish than the pure gray color.

The red luminance signals, the green luminance signals, and the blue luminance signals in the image data703are acquired in respectively different phases, so that the blue, red, and green images are colored in this order in three-pixel cycles. In other words, a color shift has occurred in an edge area located at the boundary between the black object and the white background in the image data703.

The description returns to the flowchart inFIG. 2A.

Upon completion of the processing in step S201, the processing proceeds to step S202.

In the third exemplary embodiment, in step S202, the filter processing unit102performs convolutional filter processing on each of the pieces of image data acquired using the respective kinds (red, green, and blue) of photosensitive elements under the control of the main control unit110.

Specifically, the filter processing unit102performs filter processing on the red image data700, the green image data701, and the blue image data702individually under the control of the main control unit110. Results obtained by performing the filter processing on the image data700,701, and702using the filter coefficient matrix611inFIG. 6are image data710,711, and712, respectively. The evenness in the edge areas is improved by the effect of the filter processing as in the first exemplary embodiment.

Color image data obtained by combining the pieces of image data710(red),711(green), and712(blue) is schematically represented as image data713. In the image data713, “W”, “Bk”, and “Gy” indicate a white pixel, a black pixel, and a gray pixel, respectively. The luminance signal values in the respective pixels are the same among the red image data710, the green image data711, and the blue image data712, so that the edge area is all expressed by gray pixels in the image data713. That is, the color shift has been improved.

Upon completion of the processing in step S202, the main control unit110ends the processing inFIG. 2A.

The operation in the present exemplary embodiment has been described above.

As described above, a color shift that occurs in three-pixel cycles can be improved by performing filter processing according to the present exemplary embodiment. As in the first exemplary embodiment described above, the cycle depends on the array pattern of the photosensitive elements, so that the cycle is not limited to the three-pixel cycle. Thus, even when the cycles have a length of two pixels or four or more pixels, the same effect can be obtained by averaging based on the number of pixels in each cycle.

According to each of the exemplary embodiments described above, the image quality of image data read by scanning by a sensor in which photosensitive elements having different spectral characteristics are arrayed in a specific pattern can be improved by a simple configuration. In particular, deterioration in image quality in an edge portion of the image data can be prevented. As a result, erroneous ACS determination can be also prevented.

Each of the exemplary embodiments described above has been described using, as an example, the image processing apparatus100that includes the reading unit101and the filter processing unit102as illustrated inFIG. 1. Another configuration may be employed in which the filter processing inFIG. 2Bis performed by an information processing apparatus (for example, a personal computer (PC)) that includes the filter processing unit102and is capable of receiving image data generated by reading an original document by an image reader (scanner) that includes the reading unit101, in this case, a scanner driver (scanner driver that controls the scanner that includes the reading unit101) installed in the PC may have the function of the filter processing unit102. Furthermore, another configuration may be employed in which image data generated by the scanner that includes the reading unit101is temporally stored in a storage device accessible by the PC, and the image data is processed by the filter processing unit102included in the PC.

The same effect as in the above exemplary embodiments can be produced in a case where any of these alternative configuration is employed.

In conventional techniques, there is an issue that, when reading an image using a sensor having a specific array pattern, the image quality thereof is deteriorated as a result of the occurrence of cyclic unevenness (irregularities) and a color shift. In association with this issue, there arises another issue that correct ACS determination may not be achieved in the conventional techniques. According to the present exemplary embodiments, these issues can be solved by performing filter processing on a read image to average a target pixels and neighboring pixels around the target pixel in a direction vertical to the scanning direction of the sensor.

The various data described above are not limited to the configurations and the content thereof described above and may have different configurations and content in accordance with applications and purposes thereof.

While exemplary embodiments of the present disclosure have been described above, the aspects of the present disclosure may be embodied in the form of such as a system, an apparatus, a method, a computer program, or a storage medium. Specifically, the aspects of the present disclosure may be embodied in the form of a system including a plurality of devices or may be embodied in the form of an apparatus including a single device.

Furthermore, any combination of the above exemplary embodiments shall be construed as being included in the scope of the present disclosure.

Other Embodiments

This application claims the benefit of Japanese Patent Application No. 2018-197086, filed Oct. 19, 2018, which is hereby incorporated by reference herein in its entirety.