JP2004343216A - Image processing apparatus and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus and an image processing method capable of converting color image data into monochromatic image data so that a difference between colors of characters can easily be distinguished from each other. <P>SOLUTION: A flowchart indicating a control flow in an image processing section includes: a step S1 of recognizing pixel data in a character region included in the color image data; a step S2 of discriminating the color of the character region to be any color among a plurality of predetermined colors (R, G, B, C, M, Y, Bk, W) on the basis of each of density value data of three primary colors RGB included in the pixel data of the character region; a step S6 of applying a matrix arithmetic operation (filter arithmetic operation) to the image data of the character region converted into monochromatic pixel data with a prescribed density in response to the color of the character region. The original character image is converted into a character image emphasized in a mode in response to the color of the original character image and the converted character image is recorded on recording paper. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image processing device and an image processing method for converting color image data into monochrome image data.
[0002]
[Prior art]
Some image forming apparatuses such as digital copiers convert (binarize) color image data of a document read by a scanner into monochrome image data and record a monochrome image based on the monochrome image data on recording paper. (A so-called monochrome output device).
In this type of image forming apparatus, for example, for each pixel data of color image data of a read original, a monochrome density based on density values (RGB density values) of respective color components of RGB three primary colors (red R, green G, blue B). By calculating the value, each pixel data can be converted into monochrome pixel data having a density corresponding to the brightness. In such an image forming apparatus, for example, when a document image including characters of a plurality of colors is read, the characters of each color are converted into a monochrome image having a density corresponding to the brightness, and are recorded on a recording sheet.
[0003]
However, the above-described configuration has a problem that it is difficult to distinguish characters having similar brightness (for example, black characters and dark red characters) when viewing paper after image recording.
Therefore, there has been proposed a configuration in which characters having different lightnesses are subjected to predetermined emphasis processing (for example, white characters are formed) so that characters having similar lightness can be clearly distinguished (for example, see Patent Reference 1).
[0004]
[Patent Document 1]
JP-A-7-147630
[0005]
[Problems to be solved by the invention]
However, in the above-described configuration, since the emphasis processing is performed based only on the brightness of the character, it is difficult to distinguish characters composed of different colors with the same brightness.
The present invention has been made under such a background, and provides an image processing apparatus and an image processing method capable of converting color image data into monochrome image data so that differences in character colors can be easily distinguished. With the goal.
[0006]
Means for Solving the Problems and Effects of the Invention
According to a first aspect of the present invention, there is provided an image processing apparatus (1) for converting color image data into monochrome image data, wherein the character processing unit authenticates pixel data of a character area included in the color image data. Based on the area recognition means (11, S1) and the density values (R value, G value, B value) of the three primary colors RGB included in the pixel data of the character area, a plurality of colors (R , G, B, C, M, Y, Bk, W), and character color determining means (12, S2, T1 to T9), and pixel data of the character area are converted to monochrome pixel data of a predetermined density. A monochrome conversion means (13, S3 to S5) for converting the pixel data of the character area converted by the monochrome conversion means into a color corresponding to the color of the character area determined by the character color determination means. Transform It makes it an image processing apparatus characterized by comprising a enhancement processing means for performing processing for emphasizing in a manner corresponding to the character area in the color (14, S6).
[0007]
It should be noted that the alphanumeric characters in parentheses represent corresponding components in the embodiments described below. Hereinafter, the same applies in this section.
For example, the image processing apparatus is provided in an image forming apparatus such as a digital copying machine, and a monochrome image is recorded on a recording sheet based on image data (monochrome image data) after image processing by the image processing apparatus. It has become.
According to this configuration, since the image enhancement processing is performed in a mode corresponding to the color of the character area, the original character image is converted into a character image enhanced in a mode corresponding to the color and is recorded on the recording paper. . Therefore, when looking at the sheet after the image recording, the difference in the character color can be easily distinguished depending on the emphasis mode of the character image.
[0008]
As described in the second aspect of the present invention, the emphasis processing means (14, S6) sequentially sets each pixel of the character area as a pixel of interest, and processes each monochrome pixel data of the pixel of interest and a pixel adjacent to the pixel of interest. The (matrix) operation may be performed according to the color of the character area determined by the character color determination means (12, S2, T1 to T9).
The character color determining means (12, S2, T1 to T9) calculates a difference value (| R value−G value |, | G value−B value |) of each density value data of the three primary colors RGB included in the pixel data of the character area. , | B value−R value |), and among the difference values calculated by the difference value calculating means, the maximum value and the second value of the respective density value data of the three primary colors RGB. If the difference value between the density value and the maximum density value is equal to or more than a predetermined first threshold value (V4) (YES in T3), the color of the pixel is determined to be the color corresponding to the maximum value among the three primary colors of RGB. If (12, T4) is included, the color of the character area can be determined better.
[0009]
The character color determining means (12, S2, T1 to T9) determines the maximum value of the density value data of each of the three primary colors RGB and the second among the difference values calculated by the difference value calculating means (12, T1). If the difference value from the larger density value is smaller than the first threshold value (V4) (NO in T3), the color of the pixel is calculated from the CMY3 complementary colors by the difference value calculated by the difference value calculating means. If it includes the means (12, T6) for determining the complementary color of the color corresponding to the minimum value among the density value data of the three primary colors RGB, the color of the character area can be determined even better.
[0010]
Further, the character color determination means (12, S2, T1 to T9) determines that the difference value calculated by the difference value calculation means (12, T1) is a second threshold value determined in advance corresponding to each difference value. (V1), when the third threshold value (V2) and the fourth threshold value (V3) are smaller than each other (NO in T2), means (12, T8, T9) for determining the color of the character area as a monochrome color is included. If so, the color of the character area can be determined even better.
[0011]
Furthermore, the character color determination means (12, S2, T1 to T9) determines whether all the density value data of the three primary colors RGB included in the pixel data of the character area are larger than a predetermined fifth threshold value (V5). (YES in T7), if it includes the means (12, T9) for determining the color of the character area as white, the color of the character area can be determined even better.
The monochrome conversion means (13, S3 to S5) converts the pixel data of the character area into monochrome pixel data of a predetermined density by an operation based on each density value data of the RGB primary colors included in the pixel data of the character area. 13, S3).
[0012]
The monochrome conversion means (13, S3 to S5) converts the pixel data of the character area into monochrome pixels having an average density of the pixel data determined to be black by the character color determination means (12, S2, T1 to T9). It may include means (13, S5) for converting to data.
According to a third aspect of the present invention, there is provided the setting means (4) for setting the color of the character area in correspondence with the mode of processing by the emphasis processing means (14, S6) according to the color. The image processing device (1) according to claim 1 or 2, wherein:
[0013]
According to this configuration, the emphasis processing can be performed in a manner according to the user's preference for each color of the character area, which is convenient.
According to a fourth aspect of the present invention, there is provided an image processing method for converting color image data into monochrome image data, wherein a character area recognition step (S1) for determining pixel data of a character area included in the color image data; The character color determination step (S2) of determining the color of the character area to be one of a plurality of predetermined colors based on the respective density value data (R value, G value, and B value) of the three primary colors RGB included in the pixel data of , T1 to T9), a monochrome conversion step (S3 to S5) for converting pixel data of the character area into monochrome pixel data of a predetermined density, and monochrome pixel data of the character area converted in the monochrome conversion step. An emphasis processing step (S) that performs a process for emphasizing the character area in a mode corresponding to the color by performing conversion according to the color of the character area determined in the character color determination step. ) And an image processing method characterized by comprising a.
[0014]
According to this configuration, since the image enhancement processing is performed in a mode corresponding to the color of the character area, the original character image is converted into a character image enhanced in a mode corresponding to the color and is recorded on the recording paper. . Therefore, when looking at the sheet after the image recording, the difference in the character color can be easily distinguished depending on the emphasis mode of the character image.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a digital copying machine including an image processing unit 1 according to an embodiment of the present invention.
This digital copying machine is provided with an image reading section 2 for reading a document image using, for example, a scanner. The image reading unit 2 is capable of reading a full-color original image, and each color component of three primary colors of RGB (red R, green G, and blue B) in each pixel of the color image data read by the image reading unit 2. (Pixel data) representing the density value (RGB density value) is input to the image processing unit 1.
[0016]
The image processing unit 1 is configured by, for example, a microcomputer, and functionally includes a region separation unit 11, a character color determination unit 12, a monochrome conversion unit 13, an image enhancement unit 14, a gradation processing unit 15, and the like. I have. The segmentation unit 11 certifies, based on the pixel data input from the image reading unit 2, pixels corresponding to a character area included in the color image. The character color determination unit 12 determines the color (character color) of the character area based on pixel data that has been identified as a pixel corresponding to the character area. The monochrome conversion unit 13 converts color image data into monochrome image data by converting each pixel data in the character area into monochrome pixel data having a predetermined density. The image emphasizing unit 14 performs emphasis processing on pixel data (monochrome image data) in a character area in a mode corresponding to the character color. At the time of image processing in the image processing unit 1, input pixel data (coordinate and character color data) is stored in the storage unit 16 as necessary.
[0017]
The monochrome image data that has been subjected to the enhancement processing by the image enhancement unit 14 is sent to the output unit 3 after being subjected to predetermined gradation processing by the gradation processing unit 15. The output unit 3 records a monochrome image on recording paper based on the monochrome image data sent from the image processing unit 1. The configuration of the output unit 3 is, for example, a well-known configuration, and may be such that a toner image based on monochrome image data is formed on the surface of the photoconductor, and the toner image is transferred to recording paper.
[0018]
In this embodiment, for example, the operation display unit 4 configured by a liquid crystal display with a touch panel is connected to the image processing unit 1 so as to be able to input and output. By operating the operation display unit 4, for example, the setting of the image processing mode in the image processing unit 1 can be performed.
FIG. 2 is a flowchart illustrating a flow of control in the image processing unit 1.
Referring to FIG. 2, when color image data based on a color image of a document is input from image reading unit 2, image processing unit 1 performs region separation processing in region separation unit 11 (step S1). In this region separation processing, for example, each pixel is sequentially set as a target pixel, and based on each pixel data of the target pixel and pixels adjacent to the target pixel, whether or not the target pixel is an edge pixel forming an edge of an image is determined. Is determined, pixels in the character area are identified. Thereafter, the image processing unit 1 performs a character color determination process in the character color determination unit 12 (Step S2).
[0019]
FIG. 3 is a flowchart illustrating a flow of control by the image processing unit 1 during the character color determination process. FIG. 4 is a diagram illustrating a specific example of the content of the character color determination process for a plurality of color pixels (colors CL1 to CL12). In the character color determination processing, the image processing unit 1 sequentially sets each pixel in the character area as a target pixel, and performs processing as shown in FIG. 3 for each target pixel.
Referring to FIGS. 3 and 4, in the character color determination process, first, the image processing unit 1 determines the difference value (| R value−G value) of the RGB density values (R value, G value, B value) at the pixel of interest. |, | G value−B value |, | B value−R value |) (step T1). Then, the image processing unit 1 compares each difference value with a corresponding threshold value (threshold values V1 to V3), and determines whether there is a difference value equal to or greater than the corresponding threshold value (step S2).
[0020]
Taking the color CL1 shown in FIG. 4 as an example, the RGB density values of this color CL1 are R value = 242, G value = 60, B value = 39, and each difference value is | R value−G value | = 182, | G value−B value | = 21, | B value−R value | = 203. Therefore, among the three difference values, | R value−G value | and | B value−R value | are larger than the corresponding threshold values (threshold value V1 = 20, threshold value V3 = 30). The symbols “O” and “X” shown in FIG. 4 indicate the magnitude of the value of the column and the corresponding threshold, and “O” indicates that the value of the column is equal to or greater than the corresponding threshold. “×” indicates that the value in that column is less than the corresponding threshold value.
[0021]
When at least one difference value equal to or greater than the threshold value exists as in the example of the color CL1 (YES in step T2), the image processing unit 1 sets each density value (R value, It is determined whether or not a difference value (difference value of upper two values) between the maximum value of the G value and the B value) and the second largest density value is equal to or greater than a predetermined threshold value (threshold value V4 = 60) (step). T3). If the difference between the upper two values is equal to or greater than the threshold value V4 (YES in step T3), the image processing unit 1 determines that the color of the target pixel is a color corresponding to the maximum value of the density value ( Step T4).
[0022]
In the example of the color CL1, the upper two values are the R value and the G value, and the difference value (| R value−G value | = 182) is larger than the threshold value V4 (= 60). The pixel is determined to be a color (red R) corresponding to the maximum density value (R value = 242). Similarly, in the example of the color CL7, the target pixel is determined to be red R.
In the example of the color CL2, the upper two values are the G value and the B value, and the difference value (| G value−B value |) is larger than the threshold value V4 (= 60). , The color (green G) corresponding to the maximum density value (G value = 149). Further, in the example of the colors CL3, CL6, and CL9, since the difference value of the upper two values is larger than the threshold value V4 (= 60), the target pixel of each color CL3, CL6, and CL9 corresponds to the maximum value of the density value. The color (blue B) is determined.
[0023]
On the other hand, if the difference value of the upper two values is less than the threshold value V4 (NO in step T3), the image processing unit 1 sets the color of the target pixel to a complementary color (cyan C, magenta, magenta C) corresponding to the minimum density value. M, yellow Y) (step T6). More specifically, when the color corresponding to the minimum density value is red R, cyan C is used (in the case of color CL8), and when the color corresponding to the minimum density value is green G, magenta M is used. (In the case of color CL5), and when the color corresponding to the minimum density value is blue B, yellow Y (in the case of color CL4) is determined to be the color of the target pixel as a complementary color.
[0024]
If it is determined in step T2 that there is no difference value equal to or larger than the threshold values V1 to V3 (NO in step T2), the image processing unit 1 sets the RGB density values (R value, G value, B value). Are all greater than or equal to a predetermined threshold (threshold V5 = 210) (step T7).
Taking the color CL10 shown in FIG. 4 as an example, the RGB density values of this color CL10 are R value = 198, G value = 190, B value = 192, and each density value is greater than the threshold value V5 (= 210). Is also small. As described above, when at least one of the density values is less than the threshold value V5 (NO in step T7), the image processing unit 1 determines that the color of the target pixel is black Bk (step T8). . Similarly, in the example of the color CL11, the target pixel is determined to be black Bk.
[0025]
On the other hand, taking the color CL12 shown in FIG. 4 as an example, the RGB density values of this color CL12 are R value = 242, G value = 240, B value = 233, and each density value is equal to the threshold value V5 (= 210 ) Less than. As described above, when all the density values are equal to or more than the threshold value V5 (YES in step T7), the image processing unit 1 determines that the color of the target pixel is white W (step T9).
The coordinates of the target pixel and the data of the character color subjected to the character color determination processing in this manner are stored in the storage unit 16 (step T5).
[0026]
Referring again to FIG. 2, when the character color determination processing is completed, image processing section 1 performs monochrome conversion processing in monochrome conversion section 13 (steps S3 to S5). More specifically, first, the image processing unit 1 sequentially sets each pixel of the character area as a target pixel, and substitutes RGB density values (R value, G value, B value) for each target pixel into the following equation (1). Then, the monochrome density value (K value) of each target pixel is calculated (step S3; monochrome conversion calculation).
[0027]
K value = R value × 0.30 + G value × 0.59 + B value × 0.11 (1)
The K value is a value from “0” to “255”, and black Bk is associated with K value = 0, and white W is associated with K value = 255. That is, the monochrome values (gray densities) of 256 gradations are associated with the K values of “0” to “255”. For example, in the example of the color CL12 shown in FIG. 4, the result of the monochrome conversion operation is K value ≒ 240, and the K value corresponding to light gray close to white W is calculated. However, the monochrome conversion operation may be configured to be performed only for the pixels determined to be black Bk in the character color determination processing among the pixels in the character area.
[0028]
When the monochrome conversion operation is completed, the image processing unit 1 calculates the average value of the monochrome density values of the pixels determined as black Bk in the character color determination process (the pixels of the black character portion) among the pixels in the character area (step S4). Then, the image processing unit 1 replaces the monochrome density values of all the pixels in the character area with the average value calculated in step S4 (step S5). As a result, the monochrome density values of the pixel data of all the character areas are equalized to the average density of the pixels of the black character portion. However, the monochrome density value of the pixel data in the character area is not equalized. For example, steps S4 and S5 are omitted, and the monochrome density value of each pixel calculated by the monochrome conversion operation is directly used as the pixel data of each pixel. It may be configured to be used as.
[0029]
Thereafter, the image processing unit 1 performs an image enhancement process in the image enhancement unit 14 (Step S6). More specifically, the image processing unit 1 sequentially sets each pixel in the character area as a target pixel, and performs a matrix operation (filter operation) on each pixel data (monochrome density value) of the target pixel and a pixel adjacent to the target pixel. I do. Then, the image processing unit 1 performs, in the gradation processing unit 15, gradation processing for adjusting the density gradation of each pixel data after the image enhancement processing to a suitable gradation (step S7). This is given to the output unit 3.
[0030]
FIG. 5 is a diagram showing, in association with each other, a pattern of a filter (matrix) used in the image enhancement process and a specific example of a character form recorded on a recording sheet when the image enhancement process is performed using each filter. It is.
In this embodiment, for example, filters of six patterns P1 to P6 are stored in the storage unit 16 as filters used for the image enhancement processing. The filters of the patterns P1 to P6 are associated one-to-one with each color of red R, green G, blue B, cyan C, magenta M, and yellow Y.
[0031]
In the filter operation, for example, each monochrome density value of the target pixel and a plurality of pixels adjacent to the target pixel is extracted as a matrix having the same number of rows and columns as the filter to be used. This is performed by adding the elements of the matrix calculated by the matrix operation and dividing the sum by a predetermined value as the monochrome density value of the target pixel. In this way, the monochrome density values of all the pixels in the character area are replaced with the monochrome density values after the filter operation, and when the image forming process based on the monochrome density values is performed, as shown in FIG. Corresponding to the patterns P1 to P6, the character image emphasized (converted to a different mode) with respect to the original character image is recorded on recording paper.
[0032]
According to this embodiment, since the image enhancement processing is performed using the filters of the patterns P1 to P6 corresponding to the color of the character area, the original character image is converted into a character image emphasized in a mode corresponding to the color. Is recorded on a recording sheet. Therefore, when looking at the sheet after the image recording, the difference in the character color can be easily distinguished depending on the emphasis mode of the character image.
FIG. 6 is a diagram for describing a first modification of this embodiment, and shows a specific example of the display content of the operation display unit 4.
[0033]
In the first modification, the correspondence between the filters of the patterns P1 to P6 and the colors of red R, green G, blue B, cyan C, magenta M, and yellow Y is set in advance by operating the operation display unit 4 ( (Initial setting).
In the initial setting screen as shown in FIG. 6, two operation keys 41 and 42 for deciding whether or not to perform the image enhancement process (the process of changing the character image quality in the monochrome mode) are displayed. Is touched, the image emphasis processing is set not to be performed.
[0034]
On the other hand, when the user touches the operation key 42 displayed as “execute”, the screen is switched to a screen for setting the filter patterns P1 to P6 used in the image enhancement processing of each color, and when the setting operation ends. On the initial setting screen, a filter pattern corresponding to each set color is displayed on the setting pattern display section 43 arranged on the right side of the display of each color (Bk, R, G, B, C, M, Y). Is done. In the example of FIG. 6, the filter of pattern P2 is used for red R and green G, the filter of pattern P1 is used for blue B, the filter of pattern P3 is used for cyan C, the filter of pattern P4 is used for magenta M, and the filter of yellow Y is used for pattern. The filters of P5 are set in association with each other. “No change” is displayed on the setting pattern display section 43 corresponding to the black Bk, which indicates that the emphasis processing is not performed on the black Bk characters.
[0035]
FIG. 7 is a diagram for explaining a second modification of this embodiment, and shows a specific example of the display content of the operation display unit 4.
In the second modification, as in the first modification, the correspondence between the filters of the patterns P1 to P6 and each color of red R, green G, blue B, cyan C, magenta M, and yellow Y is set in advance. Instead, the setting can be made after the image is read by the image reading unit 2. That is, as a result of performing the area separation processing and the character color determination processing based on the image data read by the image reading unit 2, if it is determined that there are two or more types of character colors, the setting as shown in FIG. The screen is displayed.
[0036]
In the setting screen shown in FIG. 7, for example, a character determined as a color character by the character color determination processing is displayed on the thumbnail display unit 44 (thumbnail display). On the right side of each thumbnail display section 44, two operation keys 45 and 46 for determining whether or not to perform image enhancement processing (image quality change) are displayed. When the operation key 45 is touched, the setting is made not to perform the image enhancement processing, and the display of “do not perform” is displayed on the setting pattern display section 47 arranged on the right side of the operation key 46.
[0037]
On the other hand, when the user touches the operation key 46 displayed as “do”, the screen is switched to a screen for setting the filter patterns P1 to P6 used in the image enhancement processing of the character color, and the setting operation is performed. Upon completion, the set filter pattern is displayed in the corresponding setting pattern display section 47 of the original setting screen.
If there are four or more types of character colors in the image read by the image reading unit 2 and the thumbnail display corresponding to those character colors cannot all be displayed in the setting screen shown in FIG. A screen switching key may be displayed on the screen, and the screen may be switched according to the operation of the screen switching key.
[0038]
If the configuration is such that the filter patterns P1 to P6 used at the time of image enhancement processing can be set by operating the operation display unit 4 as in the first and second modified examples, a mode according to the user's preference for each character color This is convenient because the emphasis processing can be performed by using.
The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims.
[0039]
For example, the character color determination process is not limited to being performed on all pixel data in a character region, but may be performed only on any pixel data in each character region. In this case, the character color determination processing may be performed only on any one pixel data of each character area, or the character color determination processing may be performed on one pixel data of each character area and its surrounding pixel data. When the determination result of the one pixel data is different from the determination result of the surrounding pixel data, the color determined by the character color determination processing of the surrounding pixel data is determined to be the color of the character area. Configuration may be used.
[0040]
When the character color determination process is performed for all the pixel data in the character area, the RGB density values of most of the pixel data are the same (or approximately the same), and the RGB density values of some of the pixel data are substantially equal to the RGB density values. When the RGB density values of the pixel data are different (or significantly different) from the RGB density values of the pixel data, the RGB density values of some of the pixel data are disregarded, and characters are determined based on the RGB density values of most of the pixel data. A configuration in which color determination processing may be performed, or a configuration in which character color determination processing is performed by replacing the RGB density values of some of the pixel data with the RGB density values of most of the pixel data. There may be.
[0041]
Further, the character color determination process is not limited to the configuration in which the color of the character region is certified as one of red R, green G, blue B, cyan C, magenta M, yellow Y, black Bk, and white W. The color to be used may be further subdivided.
The image processing unit 1 is not limited to the configuration provided in the digital copying machine, and may be provided separately from the digital copying machine.
Further, the image processing unit 1 can be provided in connection with not only a digital copying machine but also other image forming apparatuses such as a printer and a facsimile.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a schematic configuration of a digital copying machine including an image processing unit according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a control flow in an image processing unit.
FIG. 3 is a flowchart illustrating a flow of control performed by an image processing unit during a character color determination process.
FIG. 4 is a diagram illustrating a specific example of the content of a character color determination process for a plurality of color pixels;
FIG. 5 is a diagram showing patterns of filters (matrices) used in the image enhancement processing and specific examples of the form of characters recorded on recording paper when the image enhancement processing is performed using each filter. It is.
FIG. 6 is a diagram for describing a first modification of the embodiment, and shows a specific example of display contents of an operation display unit.
FIG. 7 is a diagram for explaining a second modification of the embodiment, and shows a specific example of display contents of an operation display unit.
[Explanation of symbols]
1 Image processing unit
4 Operation display
11 Area separation unit
12 Character color judgment section
13 Monochrome converter
14 Image enhancement section

Claims (4)

An image processing apparatus for converting color image data into monochrome image data,
A character area recognition unit that recognizes pixel data of a character area included in the color image data;
Character color determining means for determining the color of the character area to be one of a plurality of predetermined colors based on each of the density value data of the three primary colors RGB included in the pixel data of the character area;
Monochrome conversion means for converting pixel data of the character area into monochrome pixel data of a predetermined density,
By converting the monochrome pixel data of the character area converted by the monochrome conversion means according to the color of the character area determined by the character color determination means, the character area is changed according to the color. An image processing apparatus comprising: an emphasis processing unit that performs a process for emphasizing the image. The emphasis processing means sequentially sets each pixel of the character area as a target pixel, and applies the pixel of interest and each monochrome pixel data of a pixel adjacent to the pixel of interest to the pixel area of the character area determined by the character color determination means. 2. The image processing apparatus according to claim 1, wherein the calculation is performed in accordance with a color. 3. The image processing apparatus according to claim 1, further comprising a setting unit configured to set a color of a character area in correspondence with a mode of processing by the emphasis processing unit according to the color. An image processing method for converting color image data into monochrome image data,
A character area recognition step of determining pixel data of a character area included in the color image data;
A character color determining step of determining the color of the character area to be one of a plurality of predetermined colors based on the respective density value data of the three primary colors RGB included in the pixel data of the character area;
A monochrome conversion step of converting pixel data of the character area into monochrome pixel data of a predetermined density;
An aspect according to the color of the character area determined by performing the conversion in the character color determination step on the monochrome pixel data of the character area converted in the monochrome conversion step. And an emphasis processing step of performing a process for emphasizing the image.

Images