JP2005130308A - Image processing apparatus, image processing system, image processing method, and program and recording medium thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus provided with a color converter having a color LUT with high color conversion accuracy by taking into account an interpolation calculation error due to visual nonlinearity of a color space including a lattice point giving a large effect on interpolation accuracy under the restriction of a storage capacity of the converter in use. <P>SOLUTION: A deviation amount calculation means 3 calculates a deviation amount between a calculation value of color data when lattice point data stored in a color LUT data storage means 4 are used and lattice point data not stored in the color LUT are calculated by interpolation calculation and an actually measured value of the color data stored in an actually measured lattice point data storage means 7. A lattice point data selection means 2 selects a lattice point required for color conversion by using the calculated deviation amount and a color LUT generating means 5 generates a color LUT having lattice point data of the selected lattice point and a color conversion means 6 executes the color conversion by using the generated color LUT. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus such as a color printer, a color copying machine, or a color management system, an image processing system, an image processing method, a program thereof, and a recording medium, and in particular, an image processing apparatus that performs color correction signal processing on a color image. The present invention relates to an image processing system, an image processing method, a program thereof, and a recording medium.

  Normally, when color conversion processing is performed using a color LUT, since color conversion is at least three-dimensional conversion, creating a color LUT corresponding to all possible inputs requires a large amount of memory. Therefore, it is not possible to have all the data. Therefore, an interpolation process using only representative data is performed. In that case, if the number of representative data allocated to the grid points is increased, the color conversion accuracy is improved, but an extra storage capacity is required.

  In general, the accuracy of color conversion can be increased by increasing the density of the lattice point spacing. This is because the accuracy of average interpolation calculation is improved. Increasing the density of grid points will require extra storage capacity to store the color LUT in the device used, so the density of grid points cannot be increased without limit, and there is a limit to increasing the color conversion accuracy. was there.

  In addition, many conventional color LUTs have the lattice point spacing equally arranged. However, in such color conversion, since the color space is not a linear space that is visually uniform in every color portion, a large part of nonlinearity is obtained. However, there is a problem that the color correction error becomes large.

  Therefore, as disclosed in Patent Documents 1, 2, and 3, the lattice point interval of the color LUT is adapted to the non-linearity, for example, the lattice point density is increased as a low density region where gradation is required. It was considered to arrange them unevenly.

  Japanese Patent Application Laid-Open No. 2004-228620 discloses a method of minimizing image quality degradation due to quantization error by finely dividing a lower density region when setting lattice points.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique of calculating color correction values easily and at high speed with a configuration in which lattice points are freely arranged.

  Patent Document 3 discloses a technique related to a hierarchical optimization method of a color correction table that adjusts a lattice point density for a color within a color reproduction range.

  Patent Document 4 discloses a technique related to a function of increasing the resolution of the LUT stepwise (increasing the number of bits) by interpolation processing. A feature is that an LUT having a large number of bits is automatically generated from an original LUT having a small number of bits by interpolation processing. Color conversion is performed after constructing the LUT by interpolating step by step until the required resolution level is reached. The lattice point density of the LUT is increased evenly in steps.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for obtaining a color deviation amount between an actual measurement value and a predicted value by color conversion using an LUT, obtaining a correction amount for eliminating the deviation amount, and correcting the LUT based on the correction amount.

  Patent Document 6 discloses a technique related to color conversion that interpolates a γ table so that the difference between a predicted value and a measured value is less than or equal to a predetermined value, and the total sum of differences is less than or equal to a predetermined value. ing.

  Patent Document 7 discloses a technique of compressing an LUT and supplying it from a server to an external device.

Patent Document 8 discloses a technique for selecting an optimum LUT from a plurality of LUTs. In the technique, an LUT including a three-color lattice point having a chromaticity value that is the smallest difference from the chromaticity value of the color sample is selected as an optimum LUT.
JP-A-9-294212 JP 2001-8044 A JP-A-8-287226 JP 2002-304621 A Japanese Patent Laid-Open No. 11-112822 JP-A-8-307714 JP 2002-64716 A JP 2001-36760 A JP-A-8-237497

  In Patent Document 1, when setting the lattice points, the lower the density region, the finer the division, the image quality deterioration due to the quantization error is minimized. However, there was a problem in that the degree of visual linearity of the color space was not taken into consideration.

  That is, since the low density area is uniformly made fine without being based on the linearity of the color space, the area where the interpolation accuracy is high without being divided finely is wasted.

  Patent Document 2 discloses a technique of calculating color correction values easily and at high speed with a configuration in which grid points are freely arranged. However, if the number of grid points increases, the required storage capacity increases. There's a problem.

  In Patent Document 7, the LUT is compressed and supplied from the server to the external device. However, since the LUT capacity is not adjusted according to the capacity of the storage device of the external device, it cannot be used depending on the LUT capacity. There is time. Further, since the LUT data does not function without all the data, the LUT cannot be used even when the communication line is down during data transfer.

  Therefore, in view of the above-described problems, the present invention provides a color conversion device using a color LUT having a configuration in which grid points to which color correction values are assigned are freely arranged, which is the best under the total number of grid points of the color LUT. By providing means for determining grid points to obtain accuracy, and by providing means for determining grid points that take into consideration the color gamut that the user places importance on, color conversion accuracy can be reduced under the constraints of the storage capacity of the equipment used. An object of the present invention is to provide an image processing apparatus, an image processing system, an image processing method, a program thereof, and a recording medium that provide a high color conversion LUT and perform high-accuracy color conversion according to a user's request and usage tendency.

  According to the first aspect of the present invention, measured value grid point data storage means having color data measured values of grid points in a color space used for color conversion, and grid points of the color LUT used for the color conversion. A color LUT data storage means for storing data, a deviation amount calculation means for calculating a deviation amount between a calculated value and an actual measurement value when interpolation calculation is performed using grid point data of the color LUT, and the deviation amount is used. The grid point data selection means for selecting the grid point data, the color LUT creation means for creating a color LUT having the selected grid point data, and the grid point data already possessed by the color LUT Grid point data updating means for updating to grid point data included in the color LUT, and color conversion means for performing color conversion using the color LUT having the updated grid point data Characterized in that the image forming apparatus.

  According to a second aspect of the present invention, the deviation amount calculating means has a function of calculating a sum of deviation amounts of representative colors in a specific color gamut or all color gamuts, and the grid point data selecting means is configured to calculate the deviation amount. The image processing apparatus according to claim 1, wherein the selected grid point data is preferentially selected so that the total sum of the values is minimized.

  The invention according to claim 3 further comprises storage capacity calculation means for calculating a storage capacity necessary for recording the selected grid point data, wherein the grid point data selection means is calculated by the storage capacity calculation means. The image processing apparatus according to claim 1, wherein the grid point data is selected based on the stored storage capacity.

  The invention according to claim 4 comprises specific color designating means for designating a color for improving color conversion accuracy, and grid point data extracting means for extracting grid point data used for color conversion of the designated color, The image processing according to claim 1, wherein the grid point data selection unit selects grid point data of a color LUT to be used for color conversion of the designated color using the extracted grid point data and the shift amount. It is a device.

  The invention described in claim 5 comprises color conversion frequency calculation means for calculating conversion frequency for each color, and the grid point data selection means selects grid point data using the conversion frequency for each color. The image processing apparatus according to item 1 is provided.

  The invention according to claim 6 is the image processing apparatus according to claim 1, wherein the deviation amount calculation means uses an actual measurement value corresponding to a lattice point of a color LUT composed of high-density lattice points. And

  According to a seventh aspect of the present invention, the color LUT creation means includes: a color LUT initial setting means for presetting a color LUT; and the grid point data selection means based on the grid point data of the initially set color LUT. The image processing apparatus according to claim 1, wherein grid points necessary for color conversion are selected.

  The invention according to claim 8 is the image processing apparatus according to claim 7, wherein the color LUT set by the color LUT initial setting means is set by default and used for color conversion.

  The invention according to claim 9 comprises a plurality of the color LUT data storage means, and selectively uses the plurality of color LUT data storage means according to the use conditions of the user for color conversion. A processing apparatus is provided.

  The invention according to claim 10 further comprises an input image type discriminating unit for discriminating the type of the input image, and the grid point data selecting unit is configured to select a color based on the input image type discriminated by the input image type discriminating unit. The image processing apparatus according to claim 1, wherein grid point data necessary for conversion is selected.

  According to the eleventh aspect of the present invention, when the input image type determining unit determines that the input image is a natural image, the grid point data selecting unit is necessary for color conversion so as not to increase the grid point density. 11. The image processing apparatus according to claim 1 or 10, which selects simple grid point data.

  The invention according to claim 12 comprises a user discriminating unit for discriminating a user and a user request detecting unit for recognizing a user request, wherein the grid point data selecting unit is discriminated by the user discriminating unit, and the user 12. The image processing apparatus according to claim 1, wherein grid image data necessary for color conversion is selected based on a user request detected by a detection unit.

  According to a thirteenth aspect of the present invention, there is provided a color LUT data storage means for storing color LUT grid point data used for color conversion, a calculated value and an actual measurement when interpolation calculation is performed using the color LUT grid point data. Shift amount calculating means for calculating a shift amount between them, grid point data selecting means for selecting the grid point data using the shift amount, and the color of each grid point in the color space used for the color conversion Color conversion data calculation apparatus comprising actual measurement grid point data storage means having actual data measurement values, and grid point data transmission means for transmitting the selected grid point data to the image processing apparatus, and the color conversion data calculation Grid point data receiving means for receiving grid point data transmitted from the apparatus, color LUT storage means for storing a color LUT having the received grid point data, and the color storage A color LUT updating means for updating a color LUT having grid point data already stored in the stage to a color LUT having the received grid point data, and a color LUT having the received grid point data. And an image processing device comprising color conversion means for color conversion, wherein the image processing device and the color conversion data calculation device have means for exchanging data with each other via a network. An image processing system is provided.

  According to a fourteenth aspect of the present invention, there is provided a grid point data selection method communication means for communicating a method for selecting grid point data of a color LUT from the image processing apparatus to the color conversion data calculation apparatus, and the color conversion data calculation apparatus. 14. The image processing according to claim 13, further comprising: means for selecting lattice point data based on the communicated lattice point data selection method; and means for transmitting the selected lattice point data to the image processing apparatus. It is a system.

  According to a fifteenth aspect of the invention, the grid point data update unit changes the grid point data already stored in the color LUT storage unit to the selected grid point data at a timing designated by a user. Item 13. The image processing apparatus according to any one of Items 1 to 12 is provided.

  According to a sixteenth aspect of the present invention, the received grid point data is transmitted at a timing when the color LUT data updating unit designates a color LUT having grid point data already stored in the color LUT storage unit. The image processing apparatus according to claim 13, wherein the image processing apparatus is changed to a color LUT having a color difference.

  The invention according to claim 17 is the image processing apparatus according to any one of claims 1 to 12, wherein the grid point data updating means sets the change contents designated by the user every time the grid point data is changed. It is characterized by that.

  The invention according to claim 18 is the image processing apparatus according to claim 13 or 14, wherein the color LUT data update means sets the change contents designated by the user every time the color LUT is changed. To do.

  According to a nineteenth aspect of the present invention, an actual value grid point data storage step for storing color data actual value of each grid point in a color space used for color conversion, and the grid point data used for the color conversion are stored. A color LUT data storage step to store, a shift amount calculation step of calculating a shift amount between a calculated value and an actual measurement value when interpolation calculation is performed using the grid point data, and the grid point using the shift amount The created color LUT has grid point data selection step for selecting data, a color LUT creation step for creating a color LUT having the selected grid point data, and grid point data that the color LUT already has. The image processing method includes a lattice point data update step for updating to lattice point data and a color conversion step using the created color LUT.

  The invention according to claim 20 further comprises a storage capacity calculation step of calculating a storage capacity required to record the selected grid point data, wherein the grid point data selection step is calculated by the storage capacity calculation step. The image processing method according to claim 19, wherein the grid point data is selected based on the stored storage capacity.

  According to a twenty-first aspect of the present invention, there is provided a readable information recording medium on which a program for causing a computer to execute the processing according to the first to twentieth aspects is recorded.

  The invention described in claim 22 is a program for causing a computer to execute the processes described in claims 1 to 20.

  According to the present invention, it is possible to construct a color LUT including grid points that greatly affect the interpolation accuracy under the limitation of the storage capacity of the device used, and to determine the color LUT grid point spacing in the color space. It is possible to construct a color LUT with high color conversion accuracy that is non-uniformly arranged so as to match the above nonlinearity and that takes into account interpolation calculation errors caused by the visually nonlinear nonlinearity of the color space. Furthermore, the color conversion accuracy can be increased in consideration of the color gamut that the user is paying attention to. Therefore, it is possible to perform optimal and high-accuracy color conversion in accordance with user requirements, usage trends, or restrictions on the storage capacity of devices used.

  One embodiment of the color conversion apparatus in the image forming apparatus according to the present invention includes a grid point data update unit 1, a grid point selection unit 2, a shift amount calculation unit 3, a color LUT data storage unit 4, and a color LUT. A creation unit 5, a color conversion unit 6, and an actual measurement grid point data storage unit 7 are provided.

  Then, using the grid point data of the color LUT data storage unit 4, the calculated value of the color data when the grid point data not held in the color LUT is calculated by interpolation calculation, and the actually measured value grid point data storage unit 7 is calculated by the shift amount calculation means 3 with respect to the actually measured value of the color data 7.

  Next, using the calculated deviation amount, the grid point data selection means 2 selects grid points necessary for color conversion, and creates a color LUT having grid point data of the selected grid points. It is characterized in that it is created by means 5 and color conversion is performed by color conversion means 6 using the created color LUT.

  According to the present embodiment, the color conversion includes the grid points that greatly affect the interpolation accuracy under the limitation of the storage capacity of the device used, and the interpolation calculation error due to the visual nonlinearity of the color space is considered. A color conversion apparatus having a highly accurate color LUT can be realized.

  The present invention relates to a color conversion apparatus using a color LUT that performs high-accuracy color conversion under the limitation of a predetermined storage capacity of an image processing apparatus.

  Embodiments of the color conversion apparatus according to the present invention will be described below with reference to the accompanying drawings. First, a schematic configuration of the color conversion apparatus of this embodiment and an outline of color correction processing in the color conversion apparatus will be described.

  FIG. 3 is a schematic configuration diagram of the color conversion apparatus according to the present embodiment. As shown in FIG. 3, the color conversion apparatus of this embodiment includes a grid point data update unit 1, a grid point data selection unit 2, a shift amount calculation unit 3, a color LUT data storage unit 4, a color LUT creation unit 5, and a color. A conversion unit 6 and an actual measurement grid point data storage unit 7 are provided.

  The color conversion apparatus in the image processing apparatus to which the present invention is applied includes at least a grid point data update unit 1, a grid point data selection unit 2, a deviation amount calculation unit 3, a color LUT data storage unit 4, and a color LUT creation unit 5. The color conversion means 6 is provided.

  The measured value grid point data storage means 7 stores measured values of color data of each grid point in the color space before color conversion.

  In this embodiment, as shown in FIG. 3, the color conversion device is provided with the measured value grid point data storage means 7. However, an apparatus including the measured value grid point data storage unit 7 may be coupled to the color conversion apparatus via a network.

  The color LUT data storage unit 4 has grid point data indicating the correspondence between the color data of each grid point and the color data after color conversion at specific coordinate values in the color space before color conversion. . Note that measured values are used for the color data of each grid point in the color space before the color conversion.

  Further, the color LUT data storage means 4 normally does not have the grid point data for all grid points in the color space. Therefore, for the grid points that do not have the grid point data in the color space, an interpolation operation is usually performed using the grid point data that the color LUT has, but the resulting color data is The value is different from the actually measured value.

  Further, the shift amount calculation means 3 uses the grid point data of the color LUT to calculate the grid point data of the grid points not held by the color LUT by interpolation calculation, and the calculated grid point data is calculated. A deviation amount (interpolation calculation error) between the calculated value of the color data obtained by using the measured value of the color data held by the measured value grid point data storage means 7 is calculated.

  Next, an outline of the color correction processing of the color conversion apparatus according to this embodiment will be described. First, the measured value grid point data storage means 7 has color data of measured values corresponding to grid points having a sufficiently high grid point density, and first prepares a color LUT composed of high density grid points. Keep it.

  Next, the grid point data selection unit 2 calculates the shift amount using the actual measurement value of the color data that the actual measurement value grid point data storage unit 7 has and the grid point data that the color LUT storage unit 4 has. .

  Subsequently, the grid point data selection unit 2 refers to the calculated deviation amount, selects, for example, grid points that do not greatly affect the interpolation accuracy, and sequentially selects the selected grid points. The color LUT having high density lattice points is deleted.

  The deletion of the grid points is performed, for example, so as to satisfy the limitation of the storage capacity of the device used and so that the total sum of the shift amounts calculated by the shift amount calculation unit 3 is minimized. Further, there may be cases where the user request, for example, the color conversion accuracy of the color gamut focused on by the user is considered.

  Next, the color LUT creation means 5 creates a color LUT having the grid point data using the grid point data obtained as a result of the above-described grid point deletion (reconstruction of the color LUT). Subsequently, the reconfigured (customized) color LUT is stored in the color LUT storage unit 4 by the lattice point data update unit 1.

  Subsequently, the color conversion unit 6 performs color conversion using the color LUT stored in the color LUT storage unit 4. Note that the color conversion apparatus may include image processing means other than the above-described constituent means.

  The color LUT customization described above is provided with a color LUT initial setting means, and further provided with a means for setting this initial setting as a default. When using the image processing apparatus, the color LUT is first customized. You may be able to do it.

  Further, the color LUT may be changed at the timing designated by the user by the grid point data updating means while using the image processing apparatus. Further, every time the color LUT is changed, the change contents of the grid point data may be set by the user.

According to the present embodiment, a color LUT including a grid point that satisfies the constraints on the storage capacity of the device used and that greatly affects the interpolation accuracy is constructed by using the deviation amount, and the color space is visually checked. It is possible to realize a color conversion apparatus having a color LUT with high color conversion accuracy in consideration of the interpolation calculation error due to the above nonlinearity.

  Next, details of color interpolation processing (correction) performed using the grid point data of the color LUT will be described with reference to the accompanying drawings. In general, there are several known methods for performing color interpolation processing (correction). Any known method may be applied to the color interpolation processing (correction) applied to the present embodiment. Here, the details of typical interpolation calculations disclosed in Patent Documents 2 and 9 will be described.

  In a color conversion device using a color LUT, for example, in the case of an input color space of three colors such as RGB, the input color space is divided into a plurality of rectangular parallelepipeds, and linear interpolation is performed using eight lattice points constituting the rectangular parallelepiped. .

  FIG. 7 is a diagram for explaining a general interpolation method. A general interpolation method for color conversion from the RGB color space to the YMC color space will be described with reference to FIG. In this description, the case where the Y component is output will be described. Note that color correction can be similarly performed for the MC component.

  First, let the input pixel value be (R, G, B). The input pixel value (R, G, B) can be represented as a point P in the three-dimensional space shown in FIG. The point P is surrounded by eight surrounding lattice points. The coordinates of the lattice points are (Ri, Gi, Bi), (Ri + 1, Gi, Bi), (Ri, Gi + 1, Bi), (Ri + 1, Gi + 1, Bi), (Ri, Gi, (Bi + 1), (Ri + 1, Gi, Bi + 1), (Ri, Gi + 1, Bi + 1), (Ri + 1, Gi + 1, Bi + 1).

  The output color correction pixel value corresponding to the grid point (Rk, Gk, Bk) is assumed to be Y (Rk, Gk, Bk). At this time, the output correction pixel value Yp (R, G, B) corresponding to the point P can be obtained by (Expression 1) shown in the following formula 1.

  However, (Lr, Lg, Lb) is a distance between lattice points in each coordinate direction, and (lr, lg, lb) is a point P (R, G, Bi) from the lattice point (Ri, Gi, Bi). The distance to each coordinate direction up to B).

  In order to obtain the interpolation data using (Equation 1) shown in Equation 1, for the input pixel value (R, G, B), the lattice point position (Ri, Gi, Bi), the distance between lattice points (Lr) , Lg, Lb), and the relative position (lr, lg, lb) within the lattice points.

  Here, FIG. 8 is a block diagram illustrating an interpolation method. In FIG. 8, the logarithmization table, the adder, and the exponentization table are collectively shown as a multiplier for the purpose of simply explaining only an essential part of the interpolation method.

  Further, the color interpolation calculation described with reference to FIG. 8 is a calculation in the case where the output color component is only one component, each RBG is input with a pixel value of 8 bits, and the color correction output Y component is output with 8 bits. .

  Reference numeral 10101 shown in FIG. 8 is a grid point distance table that inputs RGB data and outputs a grid point distance corresponding to the input data. There are three grid point distance tables 10101 corresponding to RGB.

  Reference numeral 10102 shown in FIG. 8 is an intra-grid point relative position table for inputting RGB data and outputting the relative position within the lattice point corresponding to the input data. There are three in-lattice relative position tables 10102 corresponding to RGB.

  Reference numeral 10103 shown in FIG. 8 is an intra-grid point relative position table (part 2) for inputting RGB data and outputting a second intra-grid point relative position corresponding to the input data. There are three lattice point relative position tables (No. 2) 10103 corresponding to RGB. The second relative position within the lattice point indicates (distance between lattice points−relative position within the lattice point).

  Reference numeral 10104 shown in FIG. 8 denotes a grid point address table that inputs RGB data and outputs corresponding addresses of the LUT in which color correction output values of grid points are accumulated. There are three grid point address tables 10104 corresponding to RGB.

  8, 10105 is a lattice point distance multiplier, 10107 is a relative position multiplier that multiplies the relative position in the lattice point, and 10108 is a lattice point address adder that adds the lattice point addresses to generate an LUT address. 10109 is a LUT for storing color correction output values of lattice points, 10110 is a lattice point pixel value multiplier, 10111 is a lattice point pixel value adder, and 10112 is a lattice multiplied by the added lattice point pixel value. A divider that divides by the distance between points.

  Hereinafter, specific color interpolation calculation will be described. First, the table R in the inter-lattice distance table 10101 outputs the inter-lattice distance Lr using the input 8-bit R data. Similarly, the table G outputs the inter-lattice distance Lg using the input 8-bit G data. Further, the table B outputs the inter-lattice distance Lb using the input 8-bit B data.

  Subsequently, the lattice point distances Lr, Lg, and Lb output in the lattice point distance table 10101 are input to the lattice point distance multiplier 10105. The lattice point distance multiplier 10105 performs an operation of Lr × Lg × Lb and outputs the result to the divider 10112.

  In addition, the table R in the lattice point relative position table (No. 2) 10102 outputs the lattice point relative position lr using the input 8-bit R data. Similarly, the table G outputs the relative position lg within the lattice point using the input 8-bit G data. Further, the table B outputs the relative position lb in the lattice point using the input 8-bit B data.

  Further, in the table R in the relative position in lattice point table 10103, the second relative position Lr-lr in second lattice point is output using the input 8-bit R data. Similarly, the table G outputs the second in-grid relative position Lg-lg using the input 8-bit G data. Further, the table B outputs the second relative position Lb-lb within the lattice point using the input 8-bit B data.

  Subsequently, in the relative position multiplier 10107, lr, lg, lb, Lr-lr, Lg-lg, and Lb obtained from the relative position table 10102 within the lattice point and the relative position table (part 2) 10103 within the lattice point. Using -lb, 8 types of multiplication are performed using Equations 2 to 9 shown below.

  Here, it is assumed that the space is divided into 8 for each RGB space, and the number of grid points is 9 for each color component. Therefore, the LUT 10109 stores output pixel values corresponding to 9 × 9 × 9 grid points. For example, for each RBG color space, the address of the LUT corresponding to the r-th, g-th, and b-th grid points (r, g, and b are integers from 0 to 8) is calculated by the formula r + g × 9 + b × 81. Can be obtained.

  Further, the table R in the grid point address table 10104 outputs r, the table G outputs g × 9, and the table B outputs b × 81.

  Let the LUT address corresponding to (Ri, Gi, Bi) be A. The lattice point address adder 10108 performs an operation of A = r + g × 9 + b × 81 and outputs the address of the LUT 10109 corresponding to (Ri, Gi, Bi).

  Further, the lattice point address adder 10108 calculates (r + 1) + g × 9 + b × 81 = A + 1 to calculate an address corresponding to (Ri + 1, Gi, Bi). Further, the calculation of r + (g + 1) × 9 + b × 81 = A + 9 is performed to calculate an address corresponding to (Ri, Gi + 1, Bi).

  Further, an operation of (r + 1) + (g + 1) × 9 + b × 81 = A + 10 is performed to calculate an address corresponding to (Ri + 1, Gi + 1, Bi). Further, the calculation of r + g × 9 + (b + 1) × 81 = A + 81 is performed to calculate an address corresponding to (Ri, Gi, Bi + 1).

  Further, an operation of (r + 1) + g × 9 + (b + 1) × 81 = A + 82 is performed to calculate an address corresponding to (Ri + 1, Gi, Bi + 1). Further, an operation of r + (g + 1) × 9 + (b + 1) × 81 = A + 90 is performed to calculate an address corresponding to (Ri, Gi + 1, Bi + 1). Further, an operation of (r + 1) + (g + 1) × 9 + (b + 1) × 81 = A + 91 is performed to calculate an address corresponding to (Ri + 1, Gi + 1, Bi + 1).

  Subsequently, the LUT 10109 receives pixel values Y (Ri, Gi, Bi), Y (Ri + 1, Gi, Bi), Y (Ri, Gi + 1, Bi), Y (Ri +) corresponding to the above eight addresses. 1, Gi + 1, Bi), Y (Ri, Gi, Bi + 1), Y (Ri + 1, Gi, Bi + 1), Y (Ri, Gi + 1, Bi + 1), Y (Ri +) 1, Gi + 1, Bi + 1).

  Subsequently, the lattice point pixel value multiplier 10110 multiplies the eight types of output values of the relative position multiplier 10107 and the eight types of output values of the LUT 10109 to obtain the following Equation 3 (Equations 10 to 17). 8 types of output values are generated.

  Subsequently, the lattice point pixel value adder 10111 adds the above eight types of data, and generates a value obtained using Equation (18) shown below.

  Subsequently, the divider 10112 divides the calculation result in the grid point pixel value adder 10111 by the calculation result (Lr × Lg × Lb) in the grid point distance multiplier 10105 to realize the calculation of (Equation 1), The interpolation pixel value Yp (R, G, B) is output.

  The color interpolation calculation described above is a device that faithfully implements the calculation of Equation 1 (Equation 1).

  Next, the color LUT customization process of this embodiment to which the present invention is applied will be described. FIGS. 9 and 10 are diagrams illustrating a processing flow of the color LUT customization processing according to the present exemplary embodiment.

  The method for customizing a color LUT using an LUT composed of high-density grid points according to the present invention has a low-density grid point data as shown in FIG. In contrast to the method of sequentially selecting the grid points to be applied and increasing the grid point data, conversely, as shown in FIG. 10, the grid points that have high-density grid point data at the beginning and do not affect the interpolation accuracy are sequentially selected. There is a way to reduce the grid point data.

  In both of the above-described methods, the grid points are selected so as to minimize the interpolation calculation error within the range of the constraint condition of the total number of grid points (= the number of selected grid points) due to the capacity limit of the storage device. To do.

  First, as shown in FIG. 9, a method of increasing the grid point data by sequentially selecting grid points having low density grid point data and having a great influence on the interpolation accuracy will be described. As shown in FIG. 9, in step <2>, initial grid point data is initialized. In this setting, low density grid point data is selected and initialized.

  Subsequently, in step <3>, it is determined whether or not the number of grid points can be increased. If it is determined that the number of grid points cannot be increased, the customization process is terminated. If it is determined that there is room for increasing the number of grid points, the process proceeds to step <4>.

  Here, the end of the customization process in step <3> will be described. In the end determination of step <3>, that is, whether or not the number of grid points can be changed can be determined based on whether or not the storage capacity constraint condition of the device used is satisfied. That is, the determination can be made based on whether or not the total number of selected grid points falls within the range of the storage capacity restriction condition of the device used.

  Specifically, in the initial setting of grid points in step <2>, the total number of grid points (= total number of selected grid points) is set, and in the end determination in step <3>, the total number of grid points. It is determined whether or not the number of newly added grid points> the upper limit value of the total number of grid points. Note that the upper limit of the total number of grid points is typically determined by the capacity of a usable storage device.

  If the above condition is satisfied, the customization process is terminated. Otherwise, the process proceeds to step <4>.

  In step <4>, a grid point data candidate to be increased is selected, and an interpolation operation is performed on each selection candidate to calculate an interpolation error.

  Subsequently, in step <5>, after the newly added lattice point data having the largest interpolation error is determined from the selection candidates, the newly selected number of lattice points is added to the total number of lattice points (grid). The total number of points = the total number of grid points + the number of newly added grid points).

  Thereafter, the process returns to step <3>, and the end determination of <3> is performed using the newly updated total number of grid points. Thereafter, the above-described processing is repeated.

  Note that the method of increasing the number of grid points at a time in step <5> may be one grid point or a plurality of grid points. FIG. 1 is a conceptual diagram when the latter plurality of lattice points are increased. A plurality of lattice points increase around a certain lattice point.

  On the other hand, the color LUT customization process flow shown in FIG. 9 gradually increases the grid points, whereas in the process flow shown in FIG. 10, the grid points are gradually reduced. As shown in FIG. 10, a description will be given of a method of sequentially selecting grid points that have high-density grid point data and do not affect the interpolation accuracy, and reducing the grid point data.

  First, as shown in FIG. 10, in step <2>, initial grid point data is initialized. In this setting, high-density grid point data is selected and initialized. Subsequently, in step <3>, it is determined whether or not the number of grid points can be reduced. If it is determined that the number of grid points cannot be reduced, the customization process is terminated. If it is determined that there is room for reducing the number of grid points, the process proceeds to step <4>.

  Here, determination of the end of the customization process in step <3> will be described. In the end determination of step <3>, that is, whether or not the number of grid points can be changed can be determined based on whether or not the storage capacity constraint condition of the device used is satisfied. That is, the determination can be made based on whether or not the total number of selected grid points falls within the range of the storage capacity constraint condition of the device used.

  Specifically, in the initial setting of grid points in step <2>, the total number of grid points (= total number of selected grid points) is set, and in the end determination in step <3>, the total number of grid points. It is determined whether or not the number of grid points to be newly deleted <the upper limit value of the total number of grid points. Note that the upper limit of the total number of grid points is typically determined by the capacity of a usable storage device.

  If the above condition is satisfied, the customization process is terminated. Otherwise, the process proceeds to step <4>. In step <4>, a grid point data candidate to be deleted is selected, and an interpolation operation is performed on each selection candidate to calculate an interpolation error.

  Subsequently, in step <5>, after the lattice point data to be newly deleted with the smallest interpolation error is determined from the selection candidates, the number of newly selected lattice points is subtracted from the total number of lattice points (grid points). The total number = the total number of grid points−the number of grid points to be newly deleted).

  Thereafter, the process returns to step <3>, and the end determination of <3> is performed using the newly updated total number of grid points. Thereafter, the above-described processing is repeated. In addition, as a method of reducing the grid points at a time in step <5>, one grid point or a plurality of grid points may be used. FIG. 2 is a conceptual diagram when the latter plurality of lattice points are reduced. A plurality of lattice points decrease around a certain lattice point.

  In addition, the color LUT customization processing method to which the present invention is applied is not limited to the above-described method, and the lattice LUT customization process is performed so as to be within the range of the constraint conditions under different constraint conditions for each device used. The total number of points (= number of selected grid points) is controlled.

  Next, details of the construction (reconfiguration or customization) of the color LUT according to this embodiment will be described. As described above, the construction of the color LUT in the customization processing flow of the color LUT of this embodiment shown in FIGS. 9 and 10 creates the color LUT by sequentially increasing / decreasing the grid points based on the color LUT set in advance. It is characterized by that.

  At this time, the lattice point can be selected at a higher speed as the lattice point of the color LUT to be initialized is as close as possible to the finally generated lattice point. Therefore, it is desirable that the color LUT set by the color LUT initial setting means is a standard default setting that does not cause much problem if used as it is. This is because only subtle modifications are required.

  Further, in the color LUT customization process flow shown in FIG. 9, while increasing the LUT density sequentially based on the initially set color LUT, an error is calculated when interpolation is performed using the LUT. For example, an LUT having an error below a certain value is used.

  On the other hand, in the color LUT customization process flow shown in FIG. 10, while the LUT density is sequentially decreased based on the initially set color LUT, an error is calculated when interpolation is performed using the LUT. For example, an LUT having an error below a certain value is used.

  Of course, the processing flow for constructing the color LUT is not limited to that shown in FIGS. 9 and 10, and the increase and decrease of the grid points may be mixed based on the initially set color LUT.

  Next, details of the selection of grid points by the grid point data selection means 2 shown in FIG. 3 will be described. As described above, according to the present invention, in the image processing apparatus that performs color conversion using the color LUT, the calculated value of the color data and the actually measured value of the color data when the interpolation calculation is performed using the grid point data of the color LUT. The color LUT is constructed by selecting the grid points of the color LUT to be used in the color conversion using the amount of deviation (interpolation calculation error).

  Typically, in the selection of grid points in this embodiment (FIG. 9, 10: step <3>), the calculated color data and the color data at the grid points of representative colors in a specific color gamut or the entire color gamut are displayed. The color LUT is constructed by selecting the grid points so that the total sum of the deviations of the actually measured values (interpolation calculation error) is minimized.

  More specifically, in the selection of grid points (FIG. 9, 10: Step <3>), the grid points of the selection candidates are used to select the grid points of the representative color in a specific color gamut or the entire color gamut. The amount of deviation (each color) = interpolated value (each color) −measured value (each color) is calculated, the amount of deviation is calculated for all representative color grid points, and the total amount of deviation is calculated.

  At this time, a value calculated as evaluation point (each color) = importance (each color) × deviation amount (each color) may be used depending on the importance of the color to be evaluated. Here, the importance is set so that, for example, the color of the color gamut that is of high interest has a higher value.

  Finally, the grid point having the largest overall evaluation score is selected. Overall evaluation score = Σ evaluation point: Sums are obtained for all representative color grid points. The representative color evaluated here may be a color obtained by interpolation calculation. By selecting the representative color as a high-frequency color, the accuracy of the high-frequency color can be increased.

  Here, the actual measurement value of the color data is obtained, for example, by the actual measurement value grid point data storage means 6 (data server) having the actual measurement values of the color data of the high density grid points shown in FIG. 3 via the data bus or the network. As the actual measurement values, the actual measurement values of the color data stored in the actual measurement grid point data storage unit 6 are used.

  As described above, the grid points are selected so that the interpolation calculation error is the smallest within the range of the constraints on the number of grid points due to the capacity limitation of the storage device.

  The present embodiment relates to a color LUT customization processing method in a color conversion apparatus of an image processing apparatus that provides grid point data of a plurality of color LUTs to which the present invention is applied. FIG. 4 is a configuration example of a color conversion apparatus in an image processing apparatus that provides grid point data of a plurality of color LUTs to which the present invention is applied. In this configuration example, in addition to the configuration of the color conversion apparatus in the typical image processing apparatus to which the present invention is applied as shown in FIG. 3, a plurality of color LUT data storage means 4 are provided.

  In the color conversion apparatus in the image processing apparatus shown in FIG. 6, grid point data is provided to each of a plurality of color LUT data storage means 4, and usage conditions of the image processing apparatus, for example, user's color conversion accuracy are provided. Depending on the required level, an appropriate color LUT data storage unit 4 is selected from the plurality of color LUT data storage units 4, and color conversion is performed using this.

  Furthermore, an input image type discriminating unit (not shown in FIG. 4) is provided, the type of the input image is discriminated, and the grid point data can be selected based on the input image type discrimination.

  In general, when an input image to be color-converted is a natural image, it is desirable to control so that the tone continuity requirement of the image is low and the lattice point density is not increased. In this case, the upper limit value of the total number of grid points may be reduced in the end condition of step <3> of the color LUT customization process flow shown in FIGS.

  FIG. 11 is a processing flow for setting each color conversion table when there are a plurality of color LUTs of this embodiment. The present embodiment is characterized in that in the processing flow <2> #, the grid point selection parameter is set according to each color conversion table generation request.

  Specifically, in step <2> #, a grid point selection parameter (for example, an upper limit value of the total number of grid points, a grid point area (block), or an importance level for each color) is set as required.

  Subsequently, in step <3>, initial grid point data is set. For example, low density (high density) grid point data is selected and initialized.

  Specifically, in the initial setting of grid points in step <3>, the total number of grid points (= total number of selected grid points) is set, and in the end determination in step <4>, the total number of grid points. It is determined whether or not the number of newly added (deleted) grid points> (<) the upper limit value of the total number of grid points. Note that the upper limit of the total number of grid points is typically determined by the capacity of a usable storage device.

  Subsequently, in step <4>, if it is determined that the number of grid points cannot be increased (decreased), the customization process is terminated. If it is determined that there is room for increasing (decreasing) the number of grid points, the process proceeds to step <5>.

  In step <5>, a grid point data candidate is selected from the designated grid point area (block), and an interpolation operation is performed on each selection candidate to calculate an interpolation error.

  Subsequently, in step <6>, after the grid point data to be newly added (deleted) is determined from the selection candidates having the largest (smallest) interpolation error, the number of newly selected grid points is set to the total number of grid points. (The total number of grid points = the total number of grid points + (−) is the number of grid points to be newly added (deleted)).

  Thereafter, the process returns to step <3>, and the completion determination of step <4> is performed using the newly updated total number of grid points. Thereafter, the above-described processing is repeated.

  The present embodiment relates to a color LUT customization processing method in a color conversion apparatus of an image processing apparatus to which the present invention is applied to improve the color conversion accuracy of a specific color. FIG. 5 is a configuration example of a color conversion apparatus of an image processing apparatus to which the present invention is applied to improve the color conversion accuracy of a specific color.

  In this configuration example, in addition to the configuration of the color conversion apparatus in the typical image processing apparatus to which the present invention is applied as shown in FIG. 3, a color designation means for improving the color conversion accuracy, for example, the color conversion frequency is calculated. The color conversion frequency calculation means 8 is newly provided.

  The specific color typically includes a color having a high frequency of color conversion. The color conversion frequency is the frequency of the used color, and is stored in the form of a histogram, for example. The object of the present embodiment is to learn a color gamut used frequently and to improve the accuracy of the color gamut.

  The present embodiment is characterized in that color information whose color conversion accuracy is desired to be increased is used in the selection of grid point data in step <4> shown in FIGS. The method for increasing the color conversion accuracy of a specific color will be described below. However, as long as the color conversion accuracy is improved, not only the frequently used color but also the color specified by the user may be used. .

  A method for increasing the color conversion accuracy of a specific color will be specifically described. The increase / decrease of the lattice points in step <5> of FIGS. 9 and 10 may be one lattice point or a plurality of lattice points. At this time, the accuracy can be improved by partially increasing / decreasing the density of grid points in the processing flow as shown below.

<1> Start
<2> Setting the first grid point data (select low-density grid point data and initialize it)
<3> End if the number of grid points cannot be increased (decreased).
<4> Selects the color and grid point data candidates in the specified grid point area (block), and performs interpolation on each selection candidate to calculate the interpolation error.
<5> Increase (decrease) the grid point with the largest color interpolation error among selection candidates to <3>

  The present embodiment is characterized in that the grid point selection in FIGS. 9 and 10 is selected from the designated grid point area.

  Further, in this embodiment, by specifying the grid point area (block) to be designated as an important color area designated by the user, the color conversion precision of the designated color can be improved by increasing the color conversion precision.

  The method is not limited to this. As another realization method, with the processing flow shown in FIGS. 9 and 10, the designated important color tone is also obtained by increasing the importance value of the color gamut for which the designated color conversion accuracy is desired to be increased and evaluating the shift amount. The color conversion accuracy can be increased. Here, the importance is set so that, for example, the color of the color gamut that is of high interest has a higher value.

  Further, as described above, in this embodiment, the representative color for which the deviation amount is calculated is set to an important color or high-frequency color designated by the user, thereby improving the color conversion accuracy of the important color or high-frequency color. It can also be increased.

  This embodiment relates to a color LUT customization processing method in an image processing system to which the present invention is applied and which has a system configuration for providing grid point data via a network. FIG. 6 is a system configuration diagram of an image processing system to which the present invention is applied for explaining a network environment in which the present invention is applied and a server having a color LUT supplies color LUT data to an output device.

  As shown in FIG. 6, in the image processing system of this embodiment, the image processing apparatus 13 (client) and the color conversion data calculation apparatus 12 (server) exchange data with each other via a network.

  The color conversion data calculation device 12 selects the grid point using a deviation amount (interpolation calculation error) between the calculated value of the color data and the actual measurement value when interpolation calculation is performed using the grid point data of the color LUT. Grid point data selecting means 2 and grid point data transmitting means 9 for transmitting the selected grid point data to the image processing device 13 are provided.

  On the other hand, the image processing device 13 uses the grid point data receiving means 10 that receives the grid point data transmitted from the color conversion data calculation device and the color LUT that performs color conversion using the color LUT having the received grid point data. Conversion means 6 is provided.

A typical operation of the image processing system of this embodiment will be described. First, new conditions (color conversion information) such as color use frequency information or important color information are provided from the image processing device 13 to the color conversion data calculation device 12 at a preset timing.

  The new condition (color conversion information) provided from the image processing device 13 to the color conversion data calculation device 12 is transmitted by a grid point selection method communication unit not shown in FIG.

  Subsequently, based on the new condition (color conversion information), the color conversion data calculation device 12 newly extracts a color LUT by the method already described with reference to FIGS. Send to.

  Subsequently, the image processing apparatus 13 performs color conversion using the newly extracted color LUT. Note that the method for improving the color conversion accuracy of a color using the color use frequency information or the important color information is the same as the method already described.

  FIG. 12 shows a processing flow of the image processing apparatus 13. FIG. 13 shows a processing flow of the color conversion data calculation apparatus.

  In the present embodiment, transmission / reception of lattice point data or the like may be compressed in order to increase the transfer speed. In that case, it is decompressed on the receiving side. In the transfer, only information related to the corrected grid point data may be transmitted and received. In that case, the image processing apparatus 13 only needs to update the value of the corrected data. Alternatively, the grid point data to be transmitted may be transferred with priority for each color area in an order that allows color conversion using only halfway data.

  Next, the update timing adjustment of the color LUT will be described. Another typical implementation method of this embodiment is to provide a device configuration in which grid point data is provided at a timing specified by the user and the color LUT update means 11 changes the color LUT.

  The timing designated by the user is, for example, when the image processing apparatus starts up. At that time, as described above, the color LUT may be updated by the color LUT update unit 11 shown in FIG. 6 using the frequency information used up to that time. Further, it is possible to allow the user to set the change contents every time the color LUT is changed.

It is a figure explaining the customization method of the color LUT in the Example of this invention. It is a figure explaining the customization method of the other color LUT in the Example of this invention. 1 is a schematic configuration diagram of a color conversion device according to a first embodiment of the present invention. It is a schematic block diagram of the color conversion apparatus in the 2nd Example of this invention. It is a schematic block diagram of the color conversion apparatus in the 3rd Example of this invention. It is a schematic block diagram of the image processing system in the 4th Example of this invention. It is a figure for demonstrating the general interpolation calculation method applied to this invention. It is a block diagram for demonstrating the general interpolation calculation method applied to this invention. FIG. 6 is a flowchart illustrating a color LUT customization process flow according to the first embodiment. It is a figure which shows the other customization process flow of the color LUT in a 1st Example. It is a figure which shows the processing flow of the color LUT in a 2nd Example. It is a figure which shows the processing flow of the image processing apparatus in a 4th Example. It is a figure which shows the processing flow of the color conversion data calculation apparatus in a 4th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lattice point data update means 2 Lattice point data selection means 3 Deviation amount calculation means 4 Color LUT data storage means 5 Color LUT creation means 6 Color conversion means 7 Actual measurement value grid point data storage means 8 Color conversion frequency calculation means 9 Grid point data Transmission means 10 Lattice point data reception means 11 Color LUT data update means 12 Image processing device 13 Color conversion data calculation device 10101 Lattice point distance table 10102 Lattice point relative position table 10103 Lattice point relative position table (2)
10104 Lattice point address table 10105 Lattice point distance multiplier 10107 Relative position multiplier that multiplies the relative position within a lattice point 10108 Lattice point address adder 10109 LUT that accumulates color correction output values of lattice points
10110 Lattice point pixel value multiplier 10111 Lattice point pixel value adder 10112 Divider

Claims (22)

Actual value grid point data storage means having color data actual value of each grid point in the color space used for color conversion;
Color LUT data storage means for storing grid point data of the color LUT used for the color conversion;
A deviation amount calculating means for calculating a deviation amount between a calculated value and an actual measurement value when interpolation calculation is performed using grid point data of the color LUT;
Grid point data selection means for selecting the grid point data using the deviation amount;
Color LUT creation means for creating a color LUT having the selected grid point data;
Grid point data updating means for updating grid point data already possessed by the color LUT to grid point data possessed by the created color LUT;
An image processing apparatus comprising: color conversion means for performing color conversion using a color LUT having the updated lattice point data. The deviation amount calculation means has a function of calculating the sum of deviation amounts of representative colors of a specific color gamut or all color gamuts,
The image processing apparatus according to claim 1, wherein the grid point data selection unit preferentially selects the selected grid point data so that the total sum of the shift amounts is minimized. Comprising a storage capacity calculating means for calculating a storage capacity necessary for recording the selected lattice point data;
The image processing apparatus according to claim 1, wherein the grid point data selection unit selects the grid point data based on the storage capacity calculated by the storage capacity calculation unit. A specific color designating means for designating a color for improving color conversion accuracy;
Grid point data extraction means for extracting grid point data used for color conversion of the specified color,
The grid point data selection unit selects grid point data of a color LUT to be used for color conversion of the specified color using the extracted grid point data and the shift amount. The image processing apparatus according to 1. Color conversion frequency calculation means for calculating the conversion frequency for each color is provided,
The image processing apparatus according to claim 1, wherein the grid point data selection unit selects grid point data using the conversion frequency for each color.   2. The image processing apparatus according to claim 1, wherein the deviation amount calculation means uses an actual measurement value corresponding to a lattice point of a color LUT composed of high-density lattice points. The color LUT creation means includes a color LUT initial setting means for presetting the color LUT;
The image processing apparatus according to claim 1, wherein the grid point data selection unit selects grid points necessary for color conversion based on the grid point data of the color LUT that is initially set.   8. The image processing apparatus according to claim 7, wherein the color LUT set by the color LUT initial setting means is set by default and used for color conversion. A plurality of color LUT data storage means;
2. The image processing apparatus according to claim 1, wherein the plurality of color LUT data storage means are selectively used according to a use condition of a user to perform color conversion. Comprising an input image type discrimination means for discriminating the type of the input image;
The image processing apparatus according to claim 1, wherein the grid point data selection unit selects grid point data necessary for color conversion based on the input image type determined by the input image type determination unit.   When the input image type determining unit determines that the input image is a natural image, the grid point data selecting unit selects grid point data necessary for color conversion so as not to increase the grid point density. The image processing apparatus according to claim 1 or 10. A user identification means for identifying a user;
Comprising user request detection means for recognizing user requests,
2. The grid point data selection unit selects grid point data necessary for color conversion based on a user request detected by the user determination unit and detected by the user detection unit. The image processing apparatus according to any one of 10 and 11.   The grid point data update unit changes the grid point data already stored in the color LUT storage unit to the selected grid point data at a timing designated by a user. 13. The image processing apparatus according to any one of items 12.   The image processing apparatus according to any one of claims 1 to 12, wherein the grid point data update unit sets a change content designated by a user every time the grid point data is changed. Color LUT data storage means for storing grid point data of the color LUT used for color conversion;
A deviation amount calculation means for calculating a deviation amount between the calculated value and the actual measurement when interpolation calculation is performed using the grid point data of the color LUT;
Grid point data selection means for selecting the grid point data using the deviation amount;
Actual value grid point data storage means having color data actual value of each grid point in the color space used for the color conversion;
A color conversion data calculation device comprising: lattice point data transmission means for transmitting the selected lattice point data to the image processing device;
Grid point data receiving means for receiving grid point data transmitted from the color conversion data calculation device;
Color LUT storage means for storing a color LUT having the received grid point data;
A color LUT update means for updating a color LUT having grid point data already stored in the color storage means to a color LUT having the received grid point data;
An image processing apparatus comprising color conversion means for performing color conversion using a color LUT having the received grid point data,
An image processing system comprising means for allowing the image processing apparatus and the color conversion data calculation apparatus to exchange data with each other via a network. Grid point data selection method communication means for communicating a method for selecting grid point data of a color LUT from the image processing device to the color conversion data calculation device;
Means for selecting grid point data based on the communicated grid point data selection method, the color conversion data calculation device;
Means for transmitting the selected grid point data to the image processing device;
16. The image processing system according to claim 15, further comprising:   The color LUT data update unit changes a color LUT having grid point data already stored in the color LUT storage unit to a color LUT having the received grid point data at a timing designated by a user. The image processing system according to claim 15 or 16.   The image processing system according to claim 15 or 16, wherein the color LUT data update unit sets a change content designated by a user every time the color LUT is changed. An actual value grid point data storage step for storing color data actual value of each grid point in the color space used for color conversion; and a color LUT data storage step for storing the grid point data used for the color conversion;
A deviation amount calculating step for calculating a deviation amount between a calculated value and an actual measurement value when interpolation calculation is performed using the grid point data;
A grid point data selection step of selecting the grid point data using the shift amount;
A color LUT creation step of creating a color LUT having the selected grid point data;
A grid point data update step of updating grid point data already possessed by the color LUT to grid point data possessed by the created color LUT;
And a color conversion process using the created color LUT. A storage capacity calculating step for calculating a storage capacity necessary for recording the selected grid point data;
20. The image processing method according to claim 19, wherein the grid point data selection step selects the grid point data based on the storage capacity calculated by the storage capacity calculation step.   21. A readable information recording medium on which a program for causing a computer to execute the processing according to claim 1 is recorded.   A program for causing a computer to execute the processing according to claim 1.

Images