JP2024035723A - Image processing device, image processing method, and program - Google Patents

Abstract

To more efficiently perform color conversion processing on an input image.SOLUTION: A total of a reference table holding region A and an interpolation calculation result region B is adjusted so as to be fit in a predetermined size, and a ratio thereof is changed according to a distribution situation of colors for each image type such as graphic, portrait and a richly colored image. When a color value predicted to be possessed by an input image is largely distributed in a high saturation region known to have high reusability of a color, a size ratio of the interpolation calculation result region B is increased, and a size ratio of the reference table holding region A is lowered. On the contrary, when the color value predicted to be possessed by the input image is largely distributed in an intermediate saturation region, the size ratio of the interpolation calculation result region B is lowered, and the size ratio of the reference table holding region A is increased, compared to a case of the high saturation region. The size ratio of the reference table holding region A and the interpolation calculation result region B can be adjusted by adjusting amounts of developed data and compressed data of a reference table held by the reference table holding region A.SELECTED DRAWING: Figure 7

Description

The present invention relates to a technique for controlling memory for color conversion processing.

BACKGROUND ART Conventionally, rendering methods have been widely used in which contour information (also called edge information) of a figure is extracted from coordinate information and the like of the figure in order to draw the figure, and an image is formed based on the contour information. Documents to be printed (including text, graphics, and photographic images) are often composed of color data, and are displayed, edited, and saved as colored documents on a display or the like. When printing on paper or the like, it is common that the data is sent to a printer as PDL format data, and an image is formed and output through processing within the printer. When printing based on PDL data, various processes are performed for each page, and CMS (color management system) processing is performed as color conversion processing for the color of each object in the PDL data. When these processes are implemented in software, the processing speed depends on the amount of computational resources that the processing device has.

Patent Document 1 discloses a method in which a color look-up table (color LUT) that associates color values before and after conversion is fully developed in a cache memory in order to maximize processing speed with limited computational resources. ing. This method is effective in a processing device such as a PC that has sufficient computing resources for the amount of computing required to process PDL data, especially a large cache memory of the CPU.

Japanese Patent Application Publication No. 2008-141502

However, depending on the processing device, the computational resources may not be sufficient for the size of the PDL data, such as the size of the cache memory of the CPU being small or the bandwidth of the bus being narrow. In such cases, with the method described in Patent Document 1, the number of color LUTs that can be expanded at once is insufficient, or it takes time to read data, resulting in a decrease in processing efficiency and slowing down the processing speed. The problem is that it becomes difficult to improve.

The present invention provides an image processing device for performing a color conversion process on an input image, wherein the memory area used for the color conversion process includes a first memory area and a second memory area different from the first memory area. a setting means for setting a memory area of the input image, and storing first color conversion information in which an output color value is associated with a predetermined input color value in the first memory area; For color values that are not included in the input color values of the first color conversion information, correspond to color values obtained by performing interpolation calculation processing based on the color values and the first color conversion information. storage control means for storing the attached second color conversion information in the second memory area, and the setting means sets a size ratio of the first memory area and the second memory area, The ratio is set based on a ratio determined according to a color distribution predicted to be included in the input image.

According to the present invention, it is possible to perform color conversion processing on an input image more efficiently.

A diagram showing a schematic configuration of an image forming section in an embodiment of the present invention A diagram showing an example of a hardware configuration of an image processing device that constitutes a control board in an embodiment of the present invention. A diagram showing a schematic configuration of a printing system according to an embodiment of the present invention A diagram showing a configuration example of each module of the image processing device in Embodiment 1. A configuration diagram showing a color matching processing module in an embodiment of the present invention An overview diagram explaining general interpolation processing A diagram showing a case where the ratio of the partial interpolation value holding area A and the interpolation calculation result area B of the memory area is different in an embodiment of the present invention. A schematic diagram for explaining a ratio table in an embodiment of the present invention Flowchart outlining the flow of color conversion processing in an embodiment of the present invention A diagram showing a configuration example of each module of the image processing device in Embodiment 2 A diagram showing a schematic configuration of a memory allocator in Embodiment 3

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

<Embodiment 1>
An overview of image processing in the printing system of this embodiment will be described.

FIG. 1 shows a schematic configuration example of an image forming section in a color printer 2010 of this embodiment. In the figure, 2200 to 2230 are color ink cartridges filled with yellow (Y) color ink, magenta (M) color ink, cyan (C) color ink, and black (K) color ink, respectively. Each of the ink cartridges 2200 to 2230 and the pressure pump 2160 are connected by independent pipes for supplying ink, and the ink of each color is pumped from the pressure pump 2160 to the print head 2120 at a constant pressure. ing. Recording paper is supplied from the rear of the color printer 2010 and is fixed by a platen 2110 and a front guide roller 2150. The color printer 2010 is operated by pressing keys on the control panel 2180, and the control board 2190 controls all operations of the color printer 2010.

In order to print using the color printer 2010, a print control command and print data may be sent to the control board 2190 via an interface (not shown). When the control board 2190 receives the print control command and print data, for example, if RGB is specified in the color designation command, the control board 2190 converts the RGB data into CMYK data using its internal color processing unit, and then drives the print head 2120. to print.

FIG. 2 is a diagram illustrating an example of the hardware configuration of an image processing device that constitutes the control board 2190. The CPU 220 executes programs such as the OS and general applications loaded into the main memory (DRAM or the like) 230 from a non-volatile storage device (such as a hard disk) or ROM 240 (not shown), and realizes software functions described below.

The main memory 230 functions as the main memory, work area, etc. of the CPU 220. The ROM 240 is a nonvolatile storage area that holds an initial program for initialization processing by the CPU 220 when the power is turned on.

Since the CPU 220 shown in FIG. 2 is a CPU with a two-core configuration, it is internally equipped with CPU cores 221 and 222, and is equipped with a high-speed SRAM as a cache memory in a two-stage configuration. One is L1 caches 223 and 224 provided individually for each of the CPU cores 221 and 222, and the other is an L2 cache 225 that is common to the CPU cores 221 and 222. As a method for selecting internal lines for each cache memory, a number of methods have been proposed to improve efficiency, such as full associative, direct map, and N-way set associative methods, but any of these methods may be used.

FIG. 3 is a schematic diagram illustrating internal processing tasks in this embodiment. When print job data (hereinafter referred to as PDL (Page Description Language) data) is passed, the system task 311 detects this and issues a print start command to the PDL task 312.

After accumulating print job setting information, the PDL task 312 requests the image forming task 313 to start RIP (Raster Image Processor) processing.

The image formation task 313 starts image formation (RIP processing) while interpreting information such as figures and characters written in the PDL data, and generates raster image data. If an image is embedded in the PDL data passed at this time, the configuration is such that the image data is read from the secondary storage device as necessary. At this time, the speed at which images are read into memory is, for example, about 10 MB per second in a typical system.

On the other hand, the raster image data generated by the image forming task 313 is sequentially generated in units of bands, for example, and is passed to the PDL task 312 as raster image data. The average data generation rate assumed by the system is assumed here to be approximately 6 MB/sec. The data is then passed to the control system of the engine device, control task 314.

Control task 314 is configured to appropriately pass the received raster image data to the engine device. The speed at which data is received on the engine device side varies depending on the type of printer engine, but here, as a typical example, we assume a device that receives data at approximately 1 MB per second.

For each module, guidelines are set for image forming speed, transfer bandwidth, processing time, etc., and each module is designed to avoid bottlenecks.

FIG. 4 shows a configuration example of each module of a printer controller 400, which is an image processing apparatus in this embodiment. FIG. 4 illustrates three modules: a print control unit 411, a CMS module 412, and a RIP module 413.

The print control unit 411 is a module that executes the aforementioned system task 311 and PDL task 312, and is a module that controls the entire print process. When a print job is input, it is configured to pass the job to the lower RIP module 413 to generate raster image data for print output.

The CMS module 412 is a module in charge of CMS (color management system) processing, and is configured to be called by the RIP module 413 for color conversion processing. The CMS module 412 includes setting information for color conversion, a converter for color conversion (CONV-A, etc.) that is appropriately generated based on the setting information, and a table that holds development data used in a part of the conversion process. It has departments, etc. The converter for each color conversion calculates a desired conversion value by performing interpolation calculation processing from data such as an ICC profile or a color LUT. In addition, the converter can expand and use a color LUT consisting of interpolation calculation results in the cache memories 223 to 225 in order to further speed up processing. By holding a fixed amount of input color values that have been converted once and output color values that are the results of interpolation calculations in the cache memories 223 to 225, it is possible to omit the complementary calculation process when the same color is repeatedly converted. As described later, the input color values of the color LUT consisting of the interpolation calculation results held in the cache memory include a hash generated based on the color values in the input color space instead of the color values in the input color space. Values may also be used. In addition, the expanded data holds fixed values such as the γ value, and can be converted by simply referencing the values without having to calculate each time.

It is assumed that memory management of the cache memories 223 to 225, the main memory 230, etc. is performed by a storage control unit (not shown).

Next, interpolation processing for color conversion will be explained using FIG. 5.

A color LUT (lookup table), which is color conversion information used in color conversion based on interpolation processing, divides the input color space into cubes of a predetermined size, and calculates the input color corresponding to the vertex (grid point) of each cube. Has value only for values. If each color component corresponding to each axis constituting the input color space is composed of 8-bit values, the input color values are values from 0 to 255. In this case, if the input color space is divided into 16 cubes, the input color values of each color component in the reference table take values of 0, 15, 31, . . . , 255 at every 16 steps. When using a reference table, conventional techniques perform linear interpolation using values of adjacent grid points to obtain values between grid points. As a technique for interpolation processing, 8-point interpolation shown in FIG. 5 is widely used, and a linear calculation is performed starting from the value of each grid point. In this calculation, since addition and accumulation processing is executed, it is advantageous in terms of processing speed to have fewer points. Therefore, five-point interpolation and four-point interpolation processing have also been proposed and are widely used. However, regarding interpolation accuracy, it must be noted that the accuracy tends to decrease as the number of points decreases.

Next, interpolation processing using 8-point interpolation will be explained in more detail. In the case of 8-point interpolation, first, with respect to one predetermined color component, for example, the R-axis direction, a point located between grid points having the same value as the conversion target point Ti is derived. In the example shown in FIG. 5, an intermediate value Q1 is calculated at grid points P1 and P2, and similarly, Q2 is calculated based on P3 and P4, Q3 is calculated based on P5 and P6, and Q4 is calculated based on P7 and P8. Next, using the points Q1 to Q4, points R1 and R2 located between the grid points having the same value as the conversion target point Ti are derived for color components other than the R component, for example in the G-axis direction. Finally, using the points R1 and R2, a point S located between the grid points having the same value as the transformation target point Ti, that is, a transformation target point Ti, is derived with respect to the remaining B component, that is, the B-axis direction.

Note that, in this embodiment, as shown in FIG. 5, an interpolation processing method is used in which interpolation is performed sequentially for each component of color values. In this interpolation processing method, the interpolated value of the first component (the values of Q1, Q2, Q3, and Q4 in FIG. 7(a)) is not determined by linear interpolation calculation based on the values of grid points. , to get the value from the reference table. However, even for one component, developing a reference table for all input color values requires a large memory area. Therefore, only the reference table for the portion corresponding to the color gamut with high importance is developed, and the reference table for the portion corresponding to the color gamut with low importance is kept compressed. In this embodiment, the reference table is appropriately switched between uncompressed and compressed based on the importance of each color gamut that is set in advance for each color distribution of the input image. Note that when the compressed color gamut reference table is expanded for use, it is configured to be expanded primarily in a reserved area (not shown) (a shared area and allocated several kilobytes). ing.

FIG. 6 is a schematic diagram illustrating a memory area (interpolation result holding area B) for holding values obtained by performing interpolation calculation for color conversion. The interpolation result holding area B is an area that holds a hash table in which hash keys generated based on input color values are associated with output color values (converted values) obtained by interpolation from grid point values. be. Once a converted value is registered in a hash table, if the input color value before conversion of that converted value appears again, the hash table is searched using the hash value generated from the input color value and a matching hash key is found. , it is possible to obtain an output color value as a converted value without performing an interpolation operation. Since it takes time to perform interpolation operations and derive converted values, by retaining the converted values once calculated, output color values can be obtained without incurring processing costs (time) if the input color values are the same. becomes possible.

The size of this interpolation result holding area B is variable, and the area size is allocated based on size information instructed from a system (not shown). In the example shown in FIG. 6, registration permission is determined for an RGB input color value (0xA723CE), and then a hash key for search is generated from this input color value. The generated hash key is passed to the subsequent registration process, and if it has already been registered in the hash table, the output color value is obtained from the interpolation calculation result holding area B, and if it is not registered, it is obtained from the expanded reference table. Perform an interpolation operation on the values of grid points. The output color value obtained by the interpolation calculation is stored in a hash table held in the interpolation calculation result holding area B together with the corresponding hash key. However, the size of the interpolation result holding area B is limited by a predetermined alloc size. Therefore, the output color values and hash keys newly obtained by interpolation are stored in the hash table only if they do not exceed the predetermined alloc size set in interpolation result area B. be remembered.

FIG. 7 is a diagram showing a case where the size ratios of the reference table holding area A and the interpolation calculation result holding area B of the memory area are different. In this embodiment, the total of the reference table holding area A and the interpolation calculation result area B is adjusted to fit within a predetermined size, and is adjusted according to the color distribution status of each image type such as graphics, portraits, and richly colored images. The aim is to improve processing efficiency by changing the ratio. For example, if the color values predicted to be included in the input image are often distributed in a highly chromatic area where color reusability is known to be high, the interpolation result holding area B as shown in FIG. 7(b) The size ratio of the reference table holding area A is increased, and the size ratio of the reference table holding area A is decreased. On the other hand, if the color values that the input image is predicted to have are mostly distributed in the neutral color area, the size ratio of the interpolation result holding area B should be set as compared to the case of the high color area, as shown in FIG. 7(a). and increase the size ratio of the reference table holding area A. As shown in FIG. 7, the size ratio between the reference table holding area A and the interpolation result holding area B is adjusted by adjusting the amount of expanded data and compressed data of the reference table held in the reference table holding area A. can do. The size ratio between the reference table holding area A for the image color distribution and the interpolation calculation result holding area B may be determined experimentally, or higher processing efficiency can be pursued by optimizing it using a learning function, etc. .

FIG. 8 is a schematic diagram for explaining a ratio table representing ratio information that determines the size ratio between the reference table holding area A and the interpolation result holding area B in the memory area for each color gamut of the input color space. In this embodiment, a color LUT that associates values of grid points of a 16x16x16 cube with output color values is roughly divided into eight regions each consisting of four cubes, as shown in FIG. 8(b). IDs 1 to 8 are assigned to each area. The ratio table shown in FIG. 8(a) holds the ratio between the reference table holding area A and the interpolation result holding area B for each ID. For example, in an area where the ID of the RGB color space is "1", the ratio between the reference table holding area A and the interpolation result holding area B is set to 3:2.

FIG. 9 is a flowchart outlining the flow of color conversion processing in this embodiment.

In S911, the sizes of the cache memories 223 to 225 allocated to the CPU cores 221 and 222 are acquired from the ROM 240.

In S912, a ratio table that defines the ratio between the reference table holding area A and the interpolation result holding area B in a predetermined area of the input color space is read.

In S913, a color LUT is generated. This means, for example, color LUT synthesis processing from an input side RGB color space (such as sRGB) to an output side RGB color space (device RGB). In this embodiment, in this color LUT synthesis process, the size ratio between the reference table holding area A and the interpolation result holding area B is determined based on the ratio table read in S912.

The steps up to this point are preparation processes for the color conversion process, and S911 to S913 may be performed by a module provided within the printer controller 400, or may be performed by an external information processing device separate from the printer controller 400. good. In subsequent steps, color conversion processing is executed as appropriate for each print job.

In S914, the storage control unit that performs memory management performs job start processing including securing and initializing a cache memory area.

In S915, the CMS module 412 performs interpolation calculation using the color LUT generated in S913 to perform color conversion processing. In this color conversion process, the interpolation process that involves the interpolation calculation explained in FIG. If it appears again, the output color value is obtained from the cache memory without performing interpolation.

In S916, the print control unit 411 determines whether there is a print job. If there is a next print job, the process returns to S914; if there is no print job to process, the process proceeds to S917.

In S917, the CMS module 412 discards the color LUT generated in S913 to end the color conversion process.

In S918, the storage control unit executes print job termination processing, including releasing the cache memory, and ends the processing.

Note that in cases where the number of colors specified in the PDL data is not extremely large, problems such as memory capacity shortage will not occur, but there are often limits to the memory that can be used by the system, and it is necessary to The available memory is on the order of tens of MB. When compressed reference tables are expanded one after another, or when interpolation calculation results are stored one after another, there is a possibility that the system will run out of memory. Therefore, when the usage amount of the reference table holding area A reaches a preset threshold value, the compressed reference table will not be expanded and held from then on. Similarly, if the usage amount of the interpolation result holding area B reaches a preset threshold, no newly obtained interpolation results will be held thereafter.

Alternatively, you can assign a priority to the reference table, for example, based on the frequency of appearance at that point, quality information for each grid described in the profile, etc., and develop the reference table with a lower priority in subsequent processing. The data may also be erased from the cache memory. It is assumed that the reference table from which the expanded data has been deleted is held in the reference table holding area A as compressed data. The most frequent update of expanded data for reference tables is every time each reference table is generated, the second most frequent update is every time a reference table for each object is generated, and the next most frequent update is every time a reference table for each object is generated. This is done every time a reference table for each print job is generated. In addition, if the system side requests that the expanded data of the reference table on the cache memory be erased separately from these timings, the expanded data of the reference table with a lower priority is immediately erased from the cache memory and compressed. Retain as data.

In this embodiment, the number of calculations in the interpolation process is such that the interpolation process for the first one component is omitted by using a lookup table, so the processing speed can be improved, especially in cases where the number of colors is large. Further, since the reference tables held in the cache memory are limited to those in a specific area, the required capacity can be suppressed. As a result, the reference table can be placed even in an environment where the size of the cache memory is small, such as in an embedded processor, so that the cache memory can be used efficiently and the capacity of the CPU can be utilized to the maximum.

<Embodiment 2>
FIG. 10 shows a configuration example of each module of a printer controller 1000, which is an image processing apparatus in this embodiment. In FIG. 10, the same reference numerals are used for components common to printer controller 400 shown in FIG. 4. In the first embodiment, the size ratio between the reference table holding area A and the interpolation result holding area B on the cache memory is fixed to a preset ratio, but in the second embodiment, the size ratio determining unit 1010 The size ratio can be changed depending on the saturation of the image.

Note that in this embodiment, the distance D representing saturation is calculated from only the A value and the B value, but each of the L value, A value, and B value is weighted, and the weight of the L value is changed from the A value to the B value. The distance D may be calculated from the L value, the A value, and the B value by using a weight smaller than the weight of .

In this embodiment, the size ratio can be optimized according to the characteristics of the input image to be handled, so that the cache memory can be used more efficiently.

<Embodiment 3>
In this embodiment, assuming parallel processing modules (performing color conversion processing in parallel) in parallel processors, attention will be paid to the size of the cache memory (allocated memory allocator) used by each module. Whether or not to erase the reference table developed on the cache memory as in the first embodiment is determined based on the size of the memory allocator used by each module (thread or process).

When one image is subjected to color conversion processing using a plurality of modules, it is possible, for example, to separate the processing modules for odd-numbered bands and even-numbered bands. FIG. 11 shows a schematic configuration of a memory allocator in the third embodiment. As shown in FIG. 11, the memory allocator can have a hierarchical structure, where allocator A and allocator B are dedicated allocators for module A and module B, and the shared allocator is an allocator shared by module A and module B. In such a configuration, if a reference table expanded by one module is also needed by the other module, one module passes a copy of the pointer to the reference table to the other module. Then, a shared reference table is allocated to an area called a shared allocator shared by module A and module B. This allows the other module to refer to the reference table expanded by one module. Similarly, the interpolation result can be referenced by module A and module B by allocating it to the shared allocator.

By sharing data between module A and module B via the shared allocator in this way, it is possible to suppress the amount of expanded data of reference tables held redundantly, and increase the number of reference tables that can be expanded. Can be done. Efficient use of cache memory in this way enables faster color conversion processing.

Note that management information for managing the operation of each module is also held and managed in the shared allocator.

In this embodiment, the size of the reference table holding area A and the interpolation calculation result holding area B may be adjusted independently.

(Other examples)
The present invention provides a system or device with a program that implements one or more functions of the embodiments described above via a network or a storage medium, and one or more processors in a computer of the system or device reads and executes the program. This can also be achieved by processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

The present disclosure includes the following configurations and methods.

(Configuration 1)
An image processing device for performing color conversion processing on an input image, the image processing device comprising:
Setting means for setting a first memory area and a second memory area different from the first memory area as a memory area used in the color conversion process;
First color conversion information in which output color values are associated with predetermined input color values is stored in the first memory area, and the first color conversion information among the color values of the input image is stored in the first memory area. The second color conversion information in which color values not included in the input color values are associated with color values obtained by performing interpolation calculation processing based on the color values and the first color conversion information is added to the second color conversion information. storage control means for storing data in the second memory area;
Equipped with
The setting means sets a size ratio between the first memory area and the second memory area based on a ratio determined according to a color distribution that the input image is predicted to have.
An image processing device characterized by:

(Configuration 2)
The color distribution that the input image is predicted to have is derived based on the color distribution of a plurality of predetermined images.
The image processing device according to configuration 1, characterized in that:

(Configuration 3)
The setting means refers to ratio information defining the size ratio for each predetermined color gamut, and determines the size ratio from the color gamut in which the most color values included in the plurality of images are distributed.
The image processing device according to item 2, characterized in that:

(Configuration 4)
The storage control means compresses a part of the first color conversion information according to a size of the first memory area derived based on a memory area used for the color conversion process and the size ratio. to remember,
The image processing device according to configuration 2 or 3, characterized in that:

(Configuration 5)
The compressed portion of the first color conversion information is a portion whose input color value is a color value that appears less frequently in the input image.
The image processing device according to configuration 4, characterized in that:

(Configuration 6)
When the color conversion processing is performed by parallel processing of a plurality of processes, the storage control means includes a first memory allocator dedicated to each process and a second memory allocator shared by the plurality of processes; allocating the first color conversion information used in the process to a second memory allocator;
The image processing device according to configuration 4 or 5, characterized in that:

(Configuration 7)
The storage control means determines a portion of the first color conversion information to be compressed based on the sizes of the first memory allocator and the second memory allocator.
The image processing device according to configuration 6, characterized in that:

(Configuration 8)
The setting means determines the size ratio according to the saturation of the input image.
8. The image processing device according to any one of configurations 1 to 7, characterized in that:

(Configuration 9)
When the color value of the input image is not a Lab value, the setting means converts the color value of the input image into a Lab value, and calculates the saturation based on at least an a value and a b value of the Lab values. ,
The image processing device according to configuration 8, characterized in that:

(Configuration 10)
further comprising conversion means for color converting the color values of the input image based on the first color conversion information or the second color conversion information,
The converting means converts, among the color values of the input image, a color value that matches an input color value in the first color conversion information or the second color conversion information into an output corresponding to the input color value. The color values are converted into color values and output, and color values that do not match the input color values in the first color conversion information or the second color conversion information are subjected to interpolation calculation processing based on the first color conversion information. Convert and output the obtained color value,
The image processing device according to any one of Configurations 1 to 9, characterized in that:

(Configuration 11)
The storage control means stores a color value that does not match an input color value in the first color conversion information or the second color conversion information, among the color values of the input image, into the color value and the first color. converting into a color value obtained by performing an interpolation calculation process based on the conversion information, and storing the color value before and after the conversion in association with each other in the second memory area as part of the second color conversion information;
The image processing device according to configuration 10, characterized in that:

(Configuration 12)
the first color conversion information and the second color conversion information are color lookup tables;
The image processing device according to any one of Configurations 1 to 11, characterized in that:

(Configuration 13)
the first color conversion information is a color lookup table;
The second color conversion information is a hash table in which color values obtained by performing the interpolation calculation process are associated with hash keys generated from the color values of the input image.
The image processing device according to any one of Configurations 1 to 11, characterized in that:

(Configuration 14)
An image processing method for performing color conversion processing on an input image, the method comprising:
a setting step of setting a first memory area and a second memory area different from the first memory area as a memory area used for the color conversion process;
First color conversion information in which output color values are associated with predetermined input color values is stored in the first memory area, and the first color conversion information among the color values of the input image is stored in the first memory area. The second color conversion information in which color values not included in the input color values are associated with color values obtained by performing interpolation calculation processing based on the color values and the first color conversion information is added to the second color conversion information. a storage control step for storing data in the second memory area;
Equipped with
The setting step sets a size ratio between the first memory area and the second memory area based on a ratio determined according to a color distribution that the input image is predicted to have.
An image processing method characterized by:

(Configuration 15)
A program for causing a computer to function as the image processing apparatus according to any one of Configurations 1 to 13.

400 Printer controller 411 Print control unit 412 CMS module

Claims (15)

An image processing device for performing color conversion processing on an input image, the image processing device comprising:
Setting means for setting a first memory area and a second memory area different from the first memory area as a memory area used in the color conversion process;
First color conversion information in which output color values are associated with predetermined input color values is stored in the first memory area, and the first color conversion information among the color values of the input image is stored in the first memory area. The second color conversion information in which color values not included in the input color values are associated with color values obtained by performing interpolation calculation processing based on the color values and the first color conversion information is added to the second color conversion information. storage control means for storing data in the second memory area;
Equipped with
The setting means sets a size ratio between the first memory area and the second memory area based on a ratio determined according to a color distribution that the input image is predicted to have.
An image processing device characterized by: The color distribution that the input image is predicted to have is derived based on the color distribution of a plurality of predetermined images.
The image processing device according to claim 1, characterized in that: The setting means refers to ratio information defining the size ratio for each predetermined color gamut, and determines the size ratio from the color gamut in which the most color values included in the plurality of images are distributed.
The image processing device according to claim 2, characterized in that: The storage control means compresses a part of the first color conversion information according to a size of the first memory area derived based on a memory area used for the color conversion process and the size ratio. to remember,
The image processing device according to claim 1, characterized in that: The compressed portion of the first color conversion information is a portion whose input color value is a color value that appears less frequently in the input image.
The image processing device according to claim 4, characterized in that: When the color conversion processing is performed by parallel processing of a plurality of processes, the storage control means includes a first memory allocator dedicated to each process and a second memory allocator shared by the plurality of processes; allocating the first color conversion information used in the process to a second memory allocator;
The image processing device according to claim 4, characterized in that: The storage control means determines a portion of the first color conversion information to be compressed based on the sizes of the first memory allocator and the second memory allocator.
The image processing apparatus according to claim 6, characterized in that: The setting means determines the size ratio according to the saturation of the input image.
The image processing device according to claim 1, characterized in that: When the color value of the input image is not a Lab value, the setting means converts the color value of the input image into a Lab value, and calculates the saturation based on at least an a value and a b value of the Lab values. ,
The image processing device according to claim 8, characterized in that: further comprising conversion means for color converting the color values of the input image based on the first color conversion information or the second color conversion information,
The converting means converts, among the color values of the input image, a color value that matches an input color value in the first color conversion information or the second color conversion information into an output corresponding to the input color value. The color values are converted into color values and output, and color values that do not match the input color values in the first color conversion information or the second color conversion information are subjected to interpolation calculation processing based on the first color conversion information. Convert and output the obtained color value,
The image processing device according to claim 1, characterized in that: The storage control means stores a color value that does not match an input color value in the first color conversion information or the second color conversion information, among the color values of the input image, into the color value and the first color. converting into a color value obtained by performing an interpolation calculation process based on the conversion information, and storing the color value before and after the conversion in association with each other in the second memory area as part of the second color conversion information;
The image processing device according to claim 10. the first color conversion information and the second color conversion information are color lookup tables;
The image processing device according to any one of claims 1 to 11. the first color conversion information is a color lookup table;
The second color conversion information is a hash table in which color values obtained by performing the interpolation calculation process are associated with hash keys generated from the color values of the input image.
The image processing device according to any one of claims 1 to 11. An image processing method for performing color conversion processing on an input image, the method comprising:
a setting step of setting a first memory area and a second memory area different from the first memory area as a memory area used for the color conversion process;
First color conversion information in which output color values are associated with predetermined input color values is stored in the first memory area, and the first color conversion information among the color values of the input image is stored in the first memory area. The second color conversion information in which color values not included in the input color values are associated with color values obtained by performing interpolation calculation processing based on the color values and the first color conversion information is added to the second color conversion information. a storage control step for storing data in the second memory area;
Equipped with
The setting step sets a size ratio between the first memory area and the second memory area based on a ratio determined according to a color distribution that the input image is predicted to have.
An image processing method characterized by: A program for causing a computer to function as the image processing device according to any one of claims 1 to 11.

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