JP2008235965A - Image processing apparatus, image processing method, program, and recording medium - Google Patents

Abstract

Color correction is appropriately performed according to the type and degree of color vision so that input color image data can be easily viewed by a user with color vision impairment.
When image data is input from a color conversion unit 2 and color vision characteristic type information is input from a color vision characteristic input unit 3, a color correction unit 4 corrects a color included in the image data according to the type information. Determine the color you need. Further, based on the color vision characteristic degree information from the color vision characteristic input unit 3, a color correction amount is determined and color correction is performed. The color converter 5 converts the corrected data into image formation data.
[Selection] Figure 1

Description

  The present invention relates to an image processing apparatus, an image processing method, a program, and a recording medium that perform color correction processing according to color vision characteristics on input color image data, and output the display. Scanner, digital camera, color printer, The present invention relates to a technique suitable for color conversion devices such as color fax and color hard copy, and software for color printers operating on personal computers and workstations.

  In recent years, with the development of color image output technology for displaying and printing color images, various colored characters and color images are used for documents and web pages created by individuals and companies. In such a document, in many cases, the color itself has important information by using colored characters or the like for notation to call attention or grouping of graphs. In addition, in order to correctly understand the contents of these documents, it is necessary to recognize characters and images and to determine the difference in colors used in the documents.

  Even in a document using such various colors, it is difficult to distinguish color information when there is a defect in color vision. For example, in the case of color vision that is difficult to distinguish between red and green, it may be difficult to distinguish between red and green in a graph using red, green, and blue, or it may not be possible to distinguish at all. possible.

  By the way, according to the physiological and medical research on human color vision, the types of color blindness, such as red-green color blindness, red-green color blindness, yellow-blue color blindness, all-color blindness, etc. It is known that there is. Recently, CUDO (NPO Color Universal Design Organization) is not a line drawing that color vision is normal or abnormal, but C type / P type (strong / weak) (equivalent to conventional red-green blindness) / D type (strong / weak) ) (Equivalent to conventional red-green blindness) / T-type (equivalent to conventional yellow-blue blindness) / U-type (equivalent to conventional all-color blindness).

  Conventionally, in consideration of a user having such a color vision type, for example, in Japanese Patent Application Laid-Open No. 2004-26853, a confusion color is used from a color included in input document data so that a color used in a document can be easily distinguished. (See Non-Patent Document 1) Based on information, a set of colors that are confused with each other is determined, and a predetermined process is performed on the color portion included in the set to identify that different colors are used Adjustment is possible.

  However, in the case of the above prior art, since information on the type and degree of color vision is not used, uniform color correction can be performed regardless of the degree of color vision even for users with mild color vision disorders. Therefore, there are cases where the image becomes unnatural due to excessive correction.

  Also, in Patent Document 2, image data is processed so as to form an image in which at least one color is removed from the input color image, the hue is rotated on the color plane, and coloring of a color that should be originally used is performed. By changing the colorant to a colorant of a different color and forming an image, an image that is easy to understand for people with color blindness is formed.

  However, if one color is removed or the hue is rotated on the plane, the color of the entire image will change, affecting the discriminable colors that do not need to be corrected. The image will be very unnatural when viewed by users other than the color vision type.

  Further, in Patent Document 3, the user himself / herself designates the color vision characteristic while looking at the hue circle displayed on the operation unit, determines the user's color vision characteristic based on the information, and performs processing on the image data according to the color vision characteristic. Has changed.

JP 2004-246739 A JP 2004-80118 A JP 2004-94814 A Ota Noboru, “Color Engineering”, Tokyo Denki University Press, p. 209-211

  Patent Document 3 described above has an advantage of being able to cope with the discrimination between adjacent colors in a hue circle even when used by a user with normal color vision. However, it is difficult for a user with color blindness to input color vision characteristics, and it is difficult for a document creator to output it in advance with a color printer or the like to a user with color blindness.

The present invention has been made in view of the above problems,
An object of the present invention is to provide an image processing apparatus, an image processing method, a program, and a recording medium that perform appropriate color correction according to the type and degree of color vision so that input color image data can be easily seen by users with color vision impairment. It is to provide.

  That is, an object of the present invention is to provide an image processing apparatus that performs appropriate color correction according to the type and degree of color vision so that input color image data can be easily viewed by users with color vision impairment.

  It is an object of the present invention to provide an image processing apparatus that changes a color component to be corrected depending on the type of color vision characteristic that has been input, whether it is U-shaped or otherwise.

  Another object of the present invention is to provide an image processing apparatus capable of determining whether or not correction of a color included in an input color image signal is necessary according to the type of input color vision characteristic.

  An object of the present invention is to provide an image processing apparatus that suppresses overcorrection by changing the correction amount for the input color image data in accordance with the degree of the input color vision characteristic.

  It is an object of the present invention to provide an image processing apparatus capable of performing color correction only on the intermediate chroma and high chroma portions when the type of the color vision characteristic input is other than the U type.

  An object of the present invention is to provide an image processing apparatus capable of performing color correction only in the brightness direction when the type of the color vision characteristic inputted is a U type.

  An object of the present invention is to provide an image processing apparatus capable of suppressing a hue correction amount when an important color is included in input color image data.

  An object of the present invention is to provide an image processing apparatus that performs color correction so as to maintain continuity at the boundary between a low saturation part that does not perform color correction, and a middle saturation part and high saturation part that perform color correction. Is to provide.

  An object of the present invention is to provide an image processing method for performing appropriate color correction according to the type and degree of color vision so that the input color image data can be easily seen by a user with color vision impairment.

  An object of the present invention is to provide an image processing program for performing appropriate color correction according to the type and degree of color vision so that the input color image data can be easily seen by a user with color vision impairment.

  The present invention provides an image processing apparatus for converting an input color image signal into an image signal for image formation of a color image output apparatus, and a color vision characteristic input means for designating a type of color vision characteristic of a user or a type and degree of color vision characteristics. And color correction means for correcting the input color image signal based on the type and degree of the input color vision characteristic.

  Claims 1, 9, and 10: In an image processing device for converting an input color image signal into an image signal for image formation of a color image output device, the image processing device comprises a means for inputting the type of color vision characteristic or the type and degree of the user. By performing color correction based on the input color vision characteristics, it is possible to suppress overcorrection and perform color correction according to the type and degree of color vision of the user.

  Claims 2 and 3: By changing the color component to be corrected according to the input color vision characteristic, while making the determination of the confusion color and the color correction process simple, appropriate color correction according to the color vision characteristic of the user is performed. Is possible.

  Claim 4: By changing the correction amount in accordance with the degree of the color vision characteristic, it is possible to perform appropriate color correction while suppressing overcorrection.

  The fifth aspect of the present invention provides the saturation determination means, while simplifying the confusion color determination processing and the color correction processing in the low saturation portion of the input image data that is created with substantially different brightness. Appropriate color correction can be performed.

  Claim 6: When the input color vision type is U-type, it is appropriate for users of U-type color vision while simplifying the process by correcting only brightness without performing color correction. Color correction can be performed.

  Claim 7: When the important color is included in the input data, the hue correction amount of the important color is suppressed, so that it is possible for the user of C-type color vision to perform the color correction with less discomfort for the hue. is there.

  Claim 8: Even when color correction is not performed in the low saturation portion, it is possible to perform color correction with reduced discontinuity at the boundary with the intermediate saturation region where color correction is performed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Example 1: (A correction amount is changed based on information on the degree of color vision characteristics)
FIG. 1 shows the overall configuration of an image processing apparatus according to the present invention. An image processing apparatus shown in FIG. 1 includes a color conversion unit 2 that converts input data 1 into a color space for color correction, a color vision characteristic input unit 3 for a user to input color vision characteristics, and input data and color vision characteristics. Accordingly, a color correction unit 4 that performs color correction in response to the color correction unit 4 and a color conversion unit 5 that converts data corrected by the color correction unit 4 into image formation data depending on the image forming apparatus. The color vision characteristics refer to the type and degree of color vision.

  FIG. 2 shows a detailed configuration of the image processing apparatus according to the present invention. The color correction unit 4 includes a confusion color determination unit 45, a lightness correction unit 42, a saturation correction unit 43, and a hue correction unit 44.

  When the input color image data is input from the color conversion unit 2 and the type information of the color vision characteristic is input from the color vision characteristic input unit 3, the confusion color determination unit 45 receives the color included in the input color image data according to the type information. A color that needs to be corrected is determined, and input data and information on whether correction is necessary are sent to the lightness correction unit 42, the saturation correction unit 43, and the hue correction unit 44.

  When the lightness correction unit 42, the saturation correction unit 43, and the hue correction unit 44 receive information on the necessity of correction from the confusion color determination unit 45, the lightness correction unit 42, the saturation correction unit 43, and the hue correction unit 44 are based on the color vision characteristic degree information sent from the color vision characteristic input unit 3. The color correction amount is determined and color correction is performed. Then, the corrected data is sent to the color conversion unit 5. The color conversion unit 5 receives the image data after color correction from the color correction unit 4 and calculates image forming data for the input data using a method such as interpolation calculation using a 3D-LUT.

  Next, the operation of each processing unit will be described in detail with reference to the processing flowcharts of FIGS. First, the color conversion unit 2 converts data (RGB) input via a network interface or various storage media into a color space for performing confusion color determination and color correction in the color correction unit 2 (step S10). . Examples of the color space to be converted include a JCh space of the color appearance model CIECAM02, and a CIELAB space. Further, as will be described later, in order to facilitate the explanation of the determination of the confusion color using the confusion color line defined on the CIE xy chromaticity diagram, it is converted into a space of xy chromaticity and luminance Y ( Not shown). Note that JCh corresponds to lightness, saturation, and hue, respectively, and CIELAB has color information including lightness, saturation, and hue in a similar manner. Further, xy and Y are information on color and luminance, respectively.

  Next, the color vision characteristic input unit 3 displays a user interface as shown in FIG. 7 on the operation unit, prompts the user to input color vision characteristic information, and the user inputs the color vision characteristic (step S11).

  The confusion color determination unit 45 divides the input data for each color area used. Specifically, when the input data is image data, a widely known method can be used. For example, the method described in the chapter of region division on page 689 or less of “Image Analysis Handbook” (published by the University of Tokyo Press) can be used, and detailed description thereof will be omitted.

  In addition, when the input data is data created by software such as a general office application, the input data is divided into regions according to the data structure such as lines, characters, and figures, and stored as region information.

  Next, based on the stored area information, color information, and color vision type information sent from the color vision characteristic input unit 3, color information that is determined to represent colors that are visually impaired by color blind persons is searched. Then, a set of color information that is confused with each other is generated. However, this process is omitted when there are no colors that are confused with each other.

  The confusion color search processing method is described in Patent Document 1 described above as a confusion color search method when the color vision type information sent from the color vision characteristic input unit 3 is a color vision other than the U type. A method using a confusion line locus defined for each color vision characteristic shown in FIG. 6 can be applied, and detailed description thereof will be omitted.

  On the contrary, when the color vision type information sent from the color vision characteristic input unit 3 is U-type color vision, since the color vision is a color vision that cannot perceive color, only the information related to light and darkness such as brightness and brightness is included as color information. By using this method to search for confusion colors, the processing can be simplified (step S12).

  Next, a method for determining the color correction direction for the searched confusion color will be described. In order to be able to discriminate between the two colors determined to be confused colors (assumed to be confused color A and confused color B), the two colors are the same confused on the xy chromaticity diagram and the method of changing the brightness of each other There is a method of shifting the chromaticity in one or both directions in a direction perpendicular to the confusion line so that it does not come on the line.

  When making the brightness different, the confusion color determination unit 45 sends to the lightness correction unit 42 information for correcting the color information and lightness of the confusion color A or B to the high lightness side. The confusion color A or B may be determined at random, or it may be determined that A is always selected. Similarly, the lightness correction direction may be determined randomly or in a fixed direction. Furthermore, both the confusion colors A and B may be corrected, and any combination may be used as long as the correction directions are opposite to each other.

  When shifting the chromaticity, the confusion color determination unit 45 holds information on some representative numbers among a myriad of confusion lines defined in advance, and the confusion colors A and A of these confusion lines are stored. The confusion line with the smallest distance from B is selected. Then, a direction orthogonal to the selected confusion line is determined. In that case, the direction vector may be set at two arbitrary points on the confusion line, and the orthogonal vector may be calculated, or the orthogonal direction may be calculated from the inclination of the confusion line. Which of the confusion colors A and B is moved is the same as in the case where the brightness is different. Furthermore, both brightness and chromaticity may be moved.

  When the direction is determined, the subscript values of ΔA and ΔB in the expressions (1) and (2), that is, the unit vector in the correction direction are determined. However, when both A and B are moved, the size of the difference vector may be set to 1. At this time, the vector sizes in the A direction and the B direction may be equal to 0.5 and 0.5, or any value between 0 and 1.0 so that the sum is 1. A combination of

Next, the value of J′C′h ′ corresponding to x′y′Y ′ calculated in this way is obtained by a general calculation method. Then, correction amounts ΔJ, ΔC, Δh serving as a base from the input data are calculated as follows (step S13).
ΔJ = J−J ′
ΔC = C−C ′
Δh = h−h ′ (3)
The confusion color determination unit 45 sends the input data and the base correction amount calculated in this way to the color correction units 42 to 44 for each color component. At this time, if the values of the base correction amounts are all 0, there is no need for color correction.

Then, the lightness correction unit 42, the saturation correction unit 43, and the hue correction unit 44 are based on the data sent from the confusion color determination unit 45 and the color vision type degree information sent from the color vision characteristic input unit 3. Color correction is performed (step S14). If the corrected values are J ″, C ″, h ″, these are J ″ = J + α * ΔJ
C ″ = C + α * ΔC
h ″ = h + α * Δh (4)
Given in.

  As shown in FIG. 9A as an example, the constant α is usually set to increase the correction amount as the color vision type is higher, that is, as the degree of color blindness is higher. By setting in this way, a user with mild color blindness can suppress excessive color correction and obtain a more natural correction result. Furthermore, these are values that are appropriately set according to the level of the type of color vision that is input, and are not limited to the values shown in FIG.

  The data corrected in this way is sent to the color conversion unit 5, and in the color conversion unit 5, the image forming data depending on the image forming apparatus for the input data held in advance is set. The input data is converted into image forming data by using a method such as an interpolation operation using an LUT.

  In the embodiment described above, it is possible to perform an appropriate color conversion process that suppresses overcorrection according to the color vision characteristics.

Example 2: (Saturation determination is performed, and the low saturation part is speeded up by omitting the confusion color determination and considering the continuity at the boundary part)
In this embodiment, the saturation of input data is determined, and color correction is performed only for the intermediate saturation and high saturation portions. First, the overall configuration and operation are the same as those in the first embodiment, and are composed of the color conversion unit 2, the color vision characteristic input unit 3, the color correction unit 4, and the color conversion unit 5, and the operation of each unit is also the same.

  Next, the configuration and operation of each processing unit will be described. FIG. 3 shows the configuration of an image processing apparatus according to Embodiment 2 of the present invention. In the figure, 41 is a saturation determination unit, and the confusion color determination unit 45, lightness correction unit 42, saturation correction unit 43, and hue correction unit 44 are the same as those in the first embodiment.

  When the input color image data, for example, JCh is input from the color conversion unit 2, the saturation determination unit 41 determines whether the saturation is low saturation or medium to high saturation. Then, the saturation determination result is sent to the confusion color determination unit 45 together with the input data. Further, the correction strength coefficient may be sent simultaneously. The confusion color determination unit 45 receives the input data and the saturation determination result, and determines the confusion color based on the saturation determination result and the color vision type information input from the color vision characteristic input unit 3. If input data, necessity of correction, and correction intensity coefficient are received, these are also sent to the correction units 42 to 44. The lightness correction unit 42, saturation correction unit 43, and hue correction unit 44 convert the input color image data using the data received from the confusion color determination unit 45 and the color vision type degree information received from the color vision characteristic input unit 3. Correct and send to the color converter 5. The color conversion unit 5 calculates image forming data for the input data by using a method such as interpolation calculation using a 3D-LUT for the received corrected image data.

  Next, the operation of each processing unit will be described in detail. First, the color conversion unit 2 converts data input via a network interface or various storage media into a color space for performing confusion color determination or color correction in the color correction unit 2, and a saturation determination unit 41. Send to. When the saturation determination unit 41 receives input data from the color conversion unit 2, it performs saturation determination. For saturation determination, for example, a determination table as shown in FIG. 9B is prepared in advance. In the example of FIG. 9B, the value range of the saturation C is divided into 0 to 10 and 10 to 20, with low saturation for C = 0 to 30 and medium saturation for C = 30 to 70. , C = 70˜ is classified as high saturation. Further, a saturation correction coefficient (used when correcting a color to be described later) is set such that the value increases as the saturation increases and finally becomes 1 for each saturation range of 10 increments.

The saturation determination unit 41 searches in which saturation range of the table the saturation of the input data falls, and reads out the corresponding saturation category and correction intensity coefficient. However, the saturation determination and the setting of the correction strength coefficient may be performed by other methods. For example, a threshold value of less than 25 is set in the low saturation area, and the low saturation is set to be less than or equal to the threshold value. It may be determined whether the degree is greater than or equal to medium saturation. Also, with respect to the correction strength coefficient K,
K = 0.0 (C <25)
K = C / 75 (C <75)
K = 1.0 (C ≧ 75) (5)
Like, you may give. Further, the value of equation (5) is not limited to the above value, and any appropriate value may be set.

  Next, the saturation determination unit 41 sends the input data, the saturation determination result, and the correction strength coefficient to the confusion color determination unit 45. More specifically, the saturation determination result may be determined as to whether or not to search for a confusion color. For example, the saturation determination result is a flag such as 0 for a low saturation portion and 1 for other cases. good. When the confusion color determination unit 45 receives the data from the saturation determination unit 41, the confusion color determination unit 45 first determines whether or not to perform a confusion color search from the saturation determination result, and needs to search, that is, data from medium saturation to high saturation. If there is, the confusion color search is performed in the same manner as in the first embodiment based on the color vision type information received from the color vision characteristic input unit 3.

  Then, in addition to the same input data and base correction amount as in the first embodiment, the correction strength coefficient K is sent to the lightness correction unit 42, the saturation correction unit 43, and the hue correction unit 44. In the lightness correction unit 42, the saturation correction unit 43, and the hue correction unit 44, the following equation (6) is obtained from the data received from the confusion color determination unit 45 and the color vision type degree information received from the color vision characteristic input unit 3. Correct as follows.

J '= J + K * α * ΔJ
C ′ = C + K * α * ΔC
h ′ = h + K * α * Δh (6)
Given in.

  The data corrected in this way is sent to the color conversion unit 5, and in the color conversion unit 5, the image forming data depending on the image forming apparatus for the input data held in advance is set. The input data is converted into image forming data by using a method such as an interpolation operation using an LUT.

  In the embodiment described above, it is possible to perform color correction in the middle saturation portion or higher, and thereby, in the low saturation portion close to the achromatic color axis considered to be distinguishable by the difference between light and dark originally, By not performing unnecessary color correction, the process is simplified. In addition, by reflecting the correction intensity coefficient set according to the saturation of the input data in the color correction amount, abrupt color correction at the boundary between the low saturation part and the intermediate saturation part is suppressed, and at the boundary part It is possible to perform color correction with reduced discontinuity.

Example 3: (In the case of U type, only brightness correction is performed to speed up processing)
In this embodiment, when the color vision type input from the color vision characteristic input unit is the U type, the correction of color tone is omitted. First, the overall configuration and operation are the same as those in the first embodiment, and are composed of the color conversion unit 2, the color vision characteristic input unit 3, the color correction unit 4, and the color conversion unit 5, and the operation of each unit is also the same.

  Next, the configuration and operation of each processing unit will be described. FIG. 4 shows a configuration example of an image processing apparatus according to Embodiment 3 of the present invention. The third embodiment has the confusion color determination unit 45 and the lightness correction unit 42, and does not have the saturation and hue correction units among the color components.

  When the confusion color determination unit 45 receives input color image data from the color conversion unit 2 and data indicating that the type of color vision characteristic is U-type color vision from the color vision characteristic input unit 3, the color confusion color is based on lightness information alone. Search for. Then, the base correction amount is calculated, and the brightness information together with the input data is sent to the brightness correction section 42, and the saturation and hue information are sent to the color conversion section 5 without any processing. The color conversion unit 5 converts the received image data into image formation data by a method such as interpolation using a 3D-LUT.

  Next, the operation of each processing unit will be described in detail. When the confusion color determination unit 45 receives the input color image data from the color conversion unit 2 and the data indicating that the color vision characteristic type is U-type color vision from the color vision characteristic input unit 3, the color confusion color determination unit 45 determines the color of the confusion color based only on the brightness information. Perform a search. In the case of U-type color vision, since color cannot be perceived at all, it is not a set of colors on the same confusion line, but almost the same confusion plane (the chromaticity xy is arbitrary and the luminance Y is constant or the saturation and hue are arbitrary J (The constant surface is called a confusion surface.) The color on the upper surface may be searched as a confusion color.

  Further, the base correction amount can be calculated by the same method as the determination of the correction direction in which the lightness is different in the first embodiment because correction with different lightness is effective in the case of U-type color vision.

  Next, the confusion color determination unit 45 sends the base correction amount calculated in this way and the lightness information of the input data to the lightness correction unit 42, and the saturation and hue information of the input data to the color conversion unit 5. The brightness correction unit 42 calculates the corrected brightness based on the data received from the confusion color determination unit 45 and the color vision type degree information received from the color vision characteristic input unit 3.

J '= J + α * ΔJ
C '= C (not corrected)
h ′ = h (not corrected) (7)
Then, the brightness correction unit 42 sends the corrected brightness information J ′ to the color conversion unit 5. The color conversion unit 5 uses the lightness information of the input data received from the lightness correction unit 42 and the saturation and hue information of the input data received from the confusion color determination unit 45 by a method such as interpolation calculation as in the first and second embodiments. And converted into data for image formation.

  In the embodiment described above, when the input color vision type is a U-type color vision, the confusion color determination and the color correction processing are simplified, and the color correction processing effective for the U-type color vision person is performed at high speed. Is possible.

Example 4: (In the case of an important color, the hue correction amount is suppressed, and color correction that is not unnatural for users of C-type color vision is performed)
In this embodiment, color correction is performed with respect to input data of important colors such as skin color, plant green, sea or sky blue, with a hue correction amount suppressed. First, the overall configuration and operation are the same as in the other embodiments, and are composed of a color conversion unit 2, a color vision characteristic input unit 3, a color correction unit 4, and a color conversion unit 5, and the operation of each unit is also the same.

  Next, the configuration and operation of each processing unit will be described. FIG. 5 shows a configuration example of an image processing apparatus according to Embodiment 4 of the present invention. In the fourth embodiment, an important color determination unit 46 is further added to the configuration of the first embodiment.

  When the input color image data is input from the color conversion unit 2, the important color determination unit 46 determines whether the color is an important color. In parallel, the input color image data is also input to the confusion color determination unit 45, and the confusion color determination unit 45 uses the color vision type information input from the color vision characteristic input unit 3 to determine whether or not a confusion color exists. The base correction amount is calculated. Next, input data and base correction amount data are sent from the confusion color determination unit 45 to the lightness correction unit 42, the saturation correction unit 43, and the hue correction unit 44. Further, color vision type degree information is sent from the color vision characteristic input unit 3 to the correction units 42 to 44. Further, the important color determination unit 46 sends the important color determination result to the hue correction unit 44.

  The lightness correction unit 42, the saturation correction unit 43, and the hue correction unit 44 perform color correction on the input color image data based on the input data, and send it to the color conversion unit 5. The color conversion unit 5 that has received the corrected color image data converts the input color image data into data for image formation by an interpolation operation using a 3D-LUT or the like that is stored in advance.

  Next, the operation of each processing unit will be described in detail. Since the operation of the confusion color determination unit 45 is the same as that of the first embodiment, the description thereof is omitted. The important color determination unit 46 determines whether or not an important color is included in the input color image data sent from the color conversion unit 2. Specifically, a table defining important color gamuts as shown in FIG. 9C is stored in advance, and it is determined whether or not each important color is included. When certain input color data is input, the important color determination unit 46 first determines whether or not the hue h is the hue range of all the important colors. Then, among each important color, only the important color including the hue of the input data is subjected to saturation determination and lightness determination. Then, when all the color components are included in the range, it is determined that the input data is the target important color. Important colors often have a hue such as skin color, sky blue, or plant green. Therefore, the hue range of all important colors is determined first, and saturation and lightness are determined. By narrowing down the important colors, it is possible to efficiently determine whether the colors are important.

  Then, the important color determination unit 46 sends an important color determination result indicating whether or not the input data is an important color to the hue correction unit 44. This determination result information may be a flag given by 0 or 1.

  Next, the lightness correction unit 42 and the saturation correction unit 43 are respectively based on the input image data and the base correction amount received from the confusion color determination unit 45 and the color vision type degree information received from the color vision characteristic input unit 3. Correct saturation. In addition to the information, the hue correction unit 44 further corrects the hue using the important color determination result from the important color determination unit 46 (Equation (8)).

J '= J + α * ΔJ
C ′ = C + α * ΔC
h ′ = h + β * α * Δh (8)
Β in the equation (8) takes a value of β = 1.0 when the important color determination unit 46 determines that it is not an important color, and performs hue correction similar to that in the first embodiment and determines that it is an important color. Takes a value of 0 ≦ β <1.0 and suppresses the hue correction amount. If it is an important color, the value of β may be any value as long as it is 0 or more and less than 1.0. For example, a value may be set for each important color as shown in FIG. The same value may be set for. The color image data that has been corrected as described above is sent to the color converter 5 and converted into image forming data in the same manner as in the other embodiments.

  In the embodiment described above, when an important color is included in the input color image data, the hue correction amount is suppressed to perform color correction considering a user with a color vision other than the C type at the same time. Even when viewed by a user with C-type color vision, that is, general color vision, it is possible to perform color correction with a little uncomfortable color tone.

Example 5: (Example for media claim)
FIG. 10 shows a hardware configuration example of the image processing system according to the present invention. The computer 10 includes a program reading device 10a, a CPU 10b for controlling the whole, a RAM 10c used as a work area for the CPU 10b, a ROM 10d for storing a control program for the CPU 10b, a hard disk 10e, a NIC 10f, a mouse 10g, a keyboard 10h, an image It includes a display 11 on which data can be displayed and information can be input by a user touching the screen directly, and an image forming apparatus 12 such as a color printer. This image processing system can be realized by, for example, a workstation or a personal computer.

  In such a configuration, the functions of the color conversion units 2 and 5 and the color correction unit 4 shown in FIG. 1 can be provided to the CPU 10b. Further, the function of the color vision characteristic input unit 3 can be provided in any of the mouse 10g, the keyboard 10h, and the display 11. Note that image processing functions such as color conversion and color correction like the CPU 10b can be provided in the form of a software package, specifically, an information recording medium such as a CD-ROM or a magnetic disk. In the example shown in FIG. 10, when an information recording medium is set, a medium driving device for driving the information recording medium is provided.

  As described above, the image processing apparatus and the image processing method according to the present invention allow a general-purpose computer system having a display or the like to read a program recorded on an information recording medium such as a CD-ROM, and perform central processing of the general-purpose computer system. The present invention can also be implemented in an apparatus configuration in which the apparatus performs color space conversion and color correction based on color vision characteristic information input from an input interface. In this case, the program for executing the image processing of the present invention, that is, the program used in the hardware system is provided in a state recorded in a recording medium. The information recording medium on which the program and the like are recorded is not limited to the CD-ROM, and for example, a ROM, RAM, flash memory, magneto-optical disk, etc. may be used. The program recorded in the recording medium is installed in a storage device incorporated in the hardware system, for example, the hard disk 10e, so that this program can be executed to realize color conversion and color correction functions.

  In addition, the program for realizing the color conversion and color correction functions of the present invention is not only provided in the form of a recording medium, but may be provided from a server by communication via a network, for example. .

1 shows the overall configuration of the present invention. The structure of Example 1 of this invention is shown. The structure of Example 2 of this invention is shown. The structure of Example 3 of this invention is shown. The structure of Example 4 of this invention is shown. It is a figure explaining the confusion line in each color vision characteristic. An example of a color vision characteristic setting screen is shown. 3 is a flowchart of color correction processing according to the first exemplary embodiment. The relationship between the input color vision degree information and the value of α is shown. An example of the configuration when the present invention is implemented by software is shown.

Explanation of symbols

1 Input data 2, 5 color conversion unit 3 Color vision characteristic input unit 4 Color correction unit

Claims (11)

  In an image processing apparatus for converting an input color image signal into an image signal for image formation of a color image output apparatus, a color vision characteristic input means for designating a user's color vision characteristic type or color vision characteristic type and degree, and the input An image processing apparatus comprising: color correction means for correcting the input color image signal based on the type and degree of the color vision characteristic.   The image processing apparatus according to claim 1, wherein the color correction unit changes a color component to be corrected according to whether the type of the input color vision characteristic is a U type or another type.   The color correction means includes confusion color determination means for determining whether or not color correction is necessary for the input color image signal based on information on a type of the input color vision characteristic. The image processing apparatus according to 1.   The image processing apparatus according to claim 1, wherein the color correction unit changes a correction amount with respect to the input color image signal based on information regarding the degree of the input color vision characteristic.   The color correction unit includes a saturation determination unit that determines the saturation of the input color image signal, the determination result of the saturation is medium saturation and high saturation, and the type of the input color vision characteristic is U type The image processing apparatus according to claim 1, wherein color correction is performed only in a middle saturation portion and a high saturation portion in the case of a type other than the above.   The image processing apparatus according to claim 1, wherein the color correction unit performs color correction only in the brightness direction when the type of the inputted color vision characteristic is a U type.   The color correction unit includes an important color determination unit that determines whether or not a color included in the input color image signal is an important color, and suppresses a hue correction amount if the color is an important color as a result of the determination. The image processing apparatus according to claim 1, wherein:   The image processing apparatus according to claim 5, wherein color correction is performed so as to maintain continuity at a boundary portion between the intermediate and high saturation portions and the low saturation portion.   In an image processing method for converting an input color image signal into an image signal for image formation of a color image output device, a color vision characteristic input step for designating a user's color vision characteristic type or color vision characteristic type and degree, and the input And a color correction step of correcting the input color image signal based on the type and degree of the color vision characteristic.   A program for causing a computer to implement the image processing method according to claim 9.   A computer-readable recording medium having recorded thereon a program for causing a computer to implement the image processing method according to claim 9.

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