JP6954079B2 - Color estimator, color estimation method and color estimation program - Google Patents

Description

The present invention relates to a color estimation device, a color estimation method, and a color estimation program. In particular, a color estimation device that estimates the color of a document in consideration of the influence of flare on a scanner profile, and a color estimation method in a system including the color estimation device. And a color estimation program that operates in a system including the color estimation device.

In devices such as scanners and printers, the device values (RGB values and CMYK values) output by the devices are device-dependent values, so a color conversion table for converting these device values to device-independent colors. (Device profile) is created, and color conversion is performed using the device profile. As a method of creating this device profile, for example, when creating a scanner profile, the color tag output by the printer (a color chart in which patches are arranged so that information on the entire color range of the printer can be obtained) is measured with the scanner. Color measurement values such as RGB values measured with a device and measured with a scanner and L * a * b * values in the CIE 1976 color space and XYZ values in the CIE 1931 color space obtained by measuring with a colorimeter. A scanner profile can be created by associating with and, and this scanner profile can be used to convert a color read by a scanner into a color in another color space.

Here, when scanning a color chart or a document with a scanner, it is necessary to detect only the reflected light from each patch in the color chart or each area in the document, but in reality, the reflection from each patch or each area is required. In addition to light, diffused reflection causes color information mixed with reflected light from the surroundings to be acquired. This phenomenon is called flare, but if the effect of flare differs between the color chart and the original, the accuracy when converting RGB of the original into color measurement values using the scanner profile deteriorates.

A method for equalizing the influence of flare has been proposed for this problem. For example, in Patent Document 1 below, an image forming apparatus including a printing unit and a color measuring unit and a control for controlling the image forming apparatus are proposed. A method for creating a chart in a system including the device, wherein the control device generates a printed image of a chart in which a plurality of patches are arranged, and instructs the image forming device to print and measure the color of the chart. The first chart creation process in which the image forming apparatus prints the chart and measures the color of each patch of the chart, and the control device acquires the color measurement value of each patch of the chart from the image forming apparatus. Then, so that the variation in the chart of the average color measurement value obtained by averaging the color measurement values of each patch in the small patch group consisting of the patch to be color-measured and the patches around the patch is within a predetermined range. The relocation process for rearranging the patches and the control device generate a printed image of the chart on which the patches are rearranged, and instruct the image forming device to print and measure the color of the chart. A configuration is disclosed in which a chart in which the patches are rearranged is printed, and a second chart creation process for measuring the color of each patch in the chart is executed.

Japanese Unexamined Patent Publication No. 2016-159540

By using the patch arrangement method of Patent Document 1 and rearranging the patches so that the RGB values around the patches are equalized, the influence of diffused reflection from around the patches is made constant regardless of which patch is measured. can do. However, when a natural image such as a person or a landscape, a chart image whose patch arrangement cannot be changed, or the like is used as the manuscript, the above patch arrangement method cannot be used.

As a result, even if a scanner profile created based on a chart in which patches are rearranged using the above patch placement method is used, the effect of flare differs between the chart and the original, and colors are used using the scanner profile. There arises a problem that the RGB values of each region of the document for conversion cannot be estimated appropriately.

The present invention has been made in view of the above problems, and a main object thereof is to cover each area of the manuscript even for manuscripts such as natural images such as people and landscapes and chart images whose patch arrangement cannot be changed. It is an object of the present invention to provide a color estimation device, a color estimation method, and a color estimation program capable of appropriately estimating the colors of the above.

One aspect of the present invention is a color estimation device, which includes an RGB value acquisition unit that acquires the first RGB value of each patch of the chart, a color measurement value acquisition unit that acquires the color measurement value of each patch of the chart, and the like. For each patch in the chart, the first RGB average value, which is the average of the RGB values of the peripheral patches including the patch, is calculated, and the first RGB value of each patch and the first RGB average value are stored in association with each other. The attachment unit and the color estimation unit that estimates the RGB value of each target color of the document are provided, and the RGB value acquisition unit includes a plurality of second RGB whose positions or ranges are changed within the region of each target color of the document. The value was acquired, and the color estimation unit calculated and calculated the second RGB average value, which is the average of the RGB values of the peripheral region including the position or range where the second RGB value was acquired, for each target color. From the plurality of second RGB average values, the second RGB average value whose difference from the first RGB average value associated with the first RGB value corresponding to the target color is equal to or less than a predetermined threshold value is specified and specified. The second RGB value acquired from the position or range corresponding to the second RGB average value is selected as the RGB value of the target color.

One aspect of the present invention is a color estimation method in a system that estimates the RGB values of each target color of a document, that is, a first acquisition process for acquiring the first RGB values of each patch of the chart, and each patch of the chart. For the second acquisition process for acquiring the color measurement value and for each patch in the chart, the first RGB average value, which is the average of the RGB values of the peripheral patches including the patch, is calculated, and the first RGB value of each patch and the said An association process for associating and storing the first RGB average value, a third acquisition process for acquiring a plurality of second RGB values whose positions or ranges are changed within the area of each target color of the document, and each target color. The second RGB average value, which is the average of the RGB values of the peripheral region including the position or range in which the second RGB value was acquired, is calculated, and the target color is selected from the plurality of calculated second RGB average values. The second RGB average value whose difference from the first RGB average value associated with the corresponding first RGB value is equal to or less than a predetermined threshold is specified, and the second RGB average value is acquired from the position or range corresponding to the specified second RGB average value. It is characterized in that a color estimation process of selecting the second RGB value as the RGB value of the target color is executed.

One aspect of the present invention is a color estimation program operated by a device in a system that estimates the RGB values of each target color of a document, and the first acquisition of acquiring the first RGB values of each patch of the chart by the device. For each process, the second acquisition process for acquiring the color measurement value of each patch in the chart, and each patch in the chart, the first RGB average value, which is the average of the RGB values of the peripheral patches including the patch, is calculated, and the first RGB average value is calculated for each patch. A mapping process for associating and storing the first RGB value and the first RGB average value, and a third acquisition process for acquiring a plurality of second RGB values whose positions or ranges are changed within the area of each target color of the document. For each of the target colors, the second RGB average value, which is the average of the RGB values of the peripheral region including the position or range where the second RGB value was acquired, is calculated, and the calculated second RGB average value is selected from among the plurality of calculated second RGB average values. , The position corresponding to the specified second RGB average value by specifying the second RGB average value whose difference from the first RGB average value associated with the first RGB value corresponding to the target color is equal to or less than a predetermined threshold value. Alternatively, it is characterized in that a color estimation process of selecting the second RGB value acquired from the range as the RGB value of the target color is executed.

According to the color estimation device, the color estimation method, and the color estimation program of the present invention, the color of each region of the document is appropriate even for a document such as a natural image such as a person or a landscape, or a chart image whose patch arrangement cannot be changed. Can be estimated to.

The reason is that when estimating the RGB value of each target color of the manuscript, the first RGB value and the color measurement value of each patch of the chart are acquired, and for each patch of the chart, the first RGB average of the peripheral patches including the patch is obtained. The value is calculated, the first RGB value of each patch and the first RGB average value are associated and stored, and a plurality of second RGB values whose positions or ranges are changed within the area of each target color of the original are acquired and each target. For the color, the second RGB average value of the peripheral region including the position or range where each second RGB value is acquired is calculated, and from the calculated plurality of second RGB average values, the first RGB value corresponding to the target color is supported. The second RGB average value whose difference from the attached first RGB average value is equal to or less than a predetermined threshold is specified, and the second RGB value obtained from the position or range corresponding to the specified second RGB average value is used as the RGB value of the target color. Because you choose.

It is a schematic diagram which shows an example of the printing system which concerns on one Example of this invention. It is a schematic diagram which shows another example of the printing system which concerns on one Example of this invention. It is a schematic diagram which shows another example of the printing system which concerns on one Example of this invention. It is a block diagram which shows the structure of the color estimation apparatus which concerns on one Example of this invention. It is a schematic diagram which shows the structural example of the printer (when including the scanner and the colorimeter) which concerns on one Example of this invention. It is a block diagram which shows the structure of the printer (when including the color estimation apparatus, the scanner and the colorimeter) which concerns on one Example of this invention. It is a flowchart which shows the operation (scanner profile creation process) of the color estimation apparatus which concerns on one Example of this invention. It is a flowchart which shows the operation (color conversion process) of the color estimation apparatus which concerns on one Example of this invention. It is a flowchart which shows the operation (color estimation processing) of the color estimation apparatus which concerns on one Example of this invention. It is a schematic diagram explaining the color estimation method (when changing the acquisition position) which concerns on one Example of this invention. It is a schematic diagram explaining the color estimation method (when changing the acquisition range) which concerns on one Example of this invention. It is a schematic diagram explaining the color estimation method (when the color changes in an object) which concerns on one Example of this invention. It is a schematic diagram explaining the influence of flare. It is a schematic diagram explaining the problem when the scanner profile of Patent Document 1 is used.

As shown in the background technology, the color obtained by scanning the original with a scanner (for example, RGB value) is used as the color of another color space (for example, L * a * b * value in CIE 1976 color space or XYZ in CIE 1931 color space. When converting to (value), a scanner profile created by measuring each patch of the color chart with a scanner and a colorimeter in advance is used, but when scanning a color chart or original with a scanner, each patch in the color chart is used. In addition to the reflected light from each region in the original, the color information mixed with the reflected light from the surroundings is acquired.

In this way, when an RGB value is acquired using a scanner, a phenomenon in which an RGB value different from the originally acquired RGB value is acquired due to diffused reflection from the periphery of the acquisition target portion is called flare. The effect of flare occurs when creating a scanner profile and when scanning a printed image with a scanner, but the effect of flare also changes because the surrounding picture is different for each chart and image. For example, as shown in FIG. 13, even if patches of the same color (L * a * b * value) are measured, the RGB values (flare RGB values) that are diffusely reflected between Chart A and Chart B are different. The acquired RGB value (flared RGB value + non-flared RGB value) changes.

As a method of reducing the influence of this flare, in Patent Document 1, as shown in FIG. 14A, when any patch is measured by rearranging the patches so that the RGB values around the patches are equalized. However, the effect of diffused reflection from around the patch is made constant, but as shown in Fig. 14 (b), manuscripts such as natural images such as people and landscapes, and chart images whose patch arrangement cannot be changed. Then, the patch arrangement method of Patent Document 1 cannot be applied. As a result, even if a scanner profile created based on a chart in which patches are rearranged using the patch arrangement method of Patent Document 1 is used, the influence of flare differs between the chart and the manuscript, and the scanner profile is used. It is not possible to properly estimate the RGB values of each area of the document for color conversion.

Therefore, in one embodiment of the present invention, the RGB values (first RGB values) of each patch are acquired in advance at the time of creating the scanner profile, and the average value of the RGB values of the peripheral patches including each patch (first RGB average). Value) is calculated, and the first RGB value and the first RGB average value are stored in association with each other. Next, when the area of the estimation target color of the original is scanned and the RGB values are acquired, a plurality of RGB values (second RGB values) in which the acquisition position or the acquisition range is changed in each estimation target color area are acquired. Then, the average value (second RGB average value) of the RGB values of the peripheral region including each acquisition position or acquisition range is calculated. Then, from the plurality of calculated second RGB average values, the second RGB average value in which the difference from the first RGB average value associated with the first RGB value corresponding to the estimation target color is equal to or less than a predetermined threshold value is specified. The second RGB value acquired from the position or range corresponding to the specified second RGB average value is selected as the RGB value of the estimation target color. Then, the scanner profile is used to convert the selected second RGB value into an L * a * b * value or the like.

In this way, by selecting the RGB value (second RGB value) of the estimated target color affected by flare as in the scanner profile, it is appropriate for manuscripts such as natural images and charts where the patch arrangement cannot be changed. The color can be estimated, and the accuracy of color conversion using the scanner profile can be improved.

In order to explain one embodiment of the present invention in more detail, the color estimation device, the color estimation method, and the color estimation program according to the embodiment of the present invention will be described with reference to FIGS. 1 to 12. 1 to 3 are schematic views showing a configuration example of a printing system of this embodiment, and FIG. 4 is a block diagram showing a configuration of a color estimation device of this embodiment. Further, FIG. 5 is a schematic diagram showing a configuration example of the printer (when including a scanner and a colorimeter) of this embodiment, and FIG. 6 is a schematic diagram showing a printer (when including a color estimator, a scanner and a colorimeter). It is a block diagram which shows the structure of. 7 to 9 are flowcharts showing the operation of the color estimation device of the present embodiment, and FIGS. 10 to 12 are schematic views illustrating the color estimation method of the present embodiment.

In the following description, the color before conversion by the scanner profile is defined as an RGB value, and the color after conversion is defined as an L * a * b * value.

As shown in FIG. 1, the printing system 10 of this embodiment includes an output instruction terminal 20, a color estimation device 30, a printer 40, a scanner 50, a colorimeter 60, and the like. These are connected via a communication network 70 such as LAN (Local Area Network) or WAN (Wide Area Network) defined by standards such as Ethernet (registered trademark), Token Ring, and FDDI (Fiber-Distributed Data Interface). .. The color estimation device 30, the printer 40, the scanner 50, and the colorimeter 60 may be connected by a dedicated line such as a PCI (Peripheral Component Interconnect) connection.

The output instruction terminal 20 is a computer device of a client, and issues a job by using a printer driver or dedicated software.

The color estimation device 30 creates a scanner profile and, if necessary, a printer profile using the color chart output from the printer 40. Further, the color estimation device 30 performs color conversion (from RGB values to L * a * b) with respect to the RGB values obtained by scanning the original output from the printer 40 based on the job issued from the output instruction terminal 20. Color conversion to * value, color conversion from L * a * b * value to CMYK value if necessary) is performed, and the image data after color conversion is transferred to the printer 40. The color conversion from the RGB value to the L * a * b * value is performed using a scanner profile created in advance, but in this embodiment, the color of each area of the document is selected in consideration of the influence of flare on the scanner profile. Estimate and perform color conversion on the estimated color. The detailed configuration of the color estimation device 30 will be described later.

The printer 40 receives image data from the color estimation device 30, forms an image based on the image data on paper, and outputs the image. The detailed configuration of the printer 40 will also be described later.

The scanner 50 is composed of, for example, three types of RGB sensors, scans a color chart or a document output from the printer 40, and outputs RGB values.

The colorimeter 60 is a spectral type (spectral photometric meter) colorimeter that can measure each wavelength of light, measures the color chart output from the printer 40, and measures the color (L * a * b). * Value, XYZ value, etc.) are output.

Note that FIG. 1 is an example of the printing system of this embodiment, and its configuration can be changed as appropriate. For example, as shown in FIG. 2, the scanner 50 and the colorimeter 60 may be built in the printer 40, or as shown in FIG. 3, the color estimation device 30 may be further built in the printer 40. May be good. Hereinafter, the color estimation device 30 and the printer 40 will be described in detail.

[Color estimator]
As shown in FIG. 4A, the color estimation device 30 includes a control unit 31, a storage unit 35, a network I / F unit 36, a display unit 37, an operation unit 38, and the like.

The control unit 31 is composed of a CPU (Central Processing Unit) 32 and memories such as a ROM (Read Only Memory) 33 and a RAM (Random Access Memory) 34, and the CPU 32 stores a control program stored in the ROM 33 and the storage unit 35. The operation of the entire color estimation device 30 is controlled by expanding and executing the RAM 34.

As shown in FIG. 4B, the control unit 31 includes an RGB value acquisition unit 31a, a color measurement value acquisition unit 31b, a profile creation unit 31c, a correspondence unit 31d, a color estimation unit 31e, a color conversion unit 31f, and the like. Also works.

The RGB value acquisition unit 31a acquires the RGB values (hereinafter, referred to as RGB values 1) of each patch of the color chart from the scanner 50 (or the in-line scanner 49a of the printer 40 described later) at the time of creating the scanner profile. .. Further, when using the scanner profile (when color conversion using the scanner profile), a plurality of RGB values in which the acquisition position or the acquisition range is changed within the region of the estimation target color of the document from the scanner 50 (or the in-line scanner 49a). (Hereinafter, referred to as RGB value 2) is acquired. At that time, the method of acquiring a plurality of RGB values 2 can be switched depending on whether the original is a natural image or a chart image. For example, when the original is a natural image, a plurality of RGB values 2 are acquired by changing the acquisition position or acquisition range in the object, and when the original is a chart image, the acquisition positions are shifted in order from the edge of the original to obtain a plurality of RGB values 2. The RGB value 2 can be acquired. Further, when the RGB value acquisition unit 31a acquires the RGB value 2 from the original, the acquisition position or the acquisition position capable of securing an area equal to or larger than the minimum reading size (for example, 64 pixels) of the scanner 50 (or the inline scanner 49a of the printer 40) or You may search for all the acquisition ranges and select the acquisition position or the acquisition range from them. Further, in order to make the influence of flare equal between the color chart and the original, the region of each estimation target color of the original is set so that the RGB value 2 can be acquired by the reading size when the RGB value 1 is acquired from the color chart. It may be divided.

At the time of creating the scanner profile, the color measurement value acquisition unit 31b starts with the color measurement value 60 (or the in-line color measurement device 49b of the printer 40 described later) to the color measurement value of each patch of the color chart (L * in this embodiment). a * b * value) is acquired.

The profile creation unit 31c has the RGB value (RGB value 1) of each patch of the color chart acquired by the RGB value acquisition unit 31a and the color measurement value (L * a) of each patch of the color chart acquired by the color measurement value acquisition unit 31b. Create a scanner profile that associates * b * values) with (converts RGB values to color measurement values (L * a * b * values)).

The association unit 31d is a peripheral patch including each patch (a patch in a predetermined range centered on each patch, based on the RGB value (RGB value 1) of each patch of the color chart acquired by the RGB value acquisition unit 31a. For example, the average value of RGB values (for example, a weighted average of RGB values, hereinafter referred to as RGB average value 1) of (3 × 3 patch) is calculated, and the RGB value 1 and the RGB average value 1 are associated with each other. It is stored in a storage unit 35 or the like. For example, a table for associating the RGB value 1 with the RGB average value 1 is created, or the RGB average value 1 corresponding to the RGB value 1 of each patch is added to the scanner profile created by the profile creation unit 31c. If the color chart is a color chart in which the patches are rearranged so that the RGB values around the patches are equalized, the RGB average value 1 may be stored for each chart, and in the case of a normal color chart, the RGB values may be stored. The RGB average value 1 may be stored for each patch.

The color estimation unit 31e analyzes the scan data of the document and extracts a region of the same color included in the document. Further, for each estimation target color of the document, a peripheral region including an acquisition position or acquisition range in which each RGB value 2 is acquired (a predetermined range centered on each acquisition position or acquisition range (preferably, the peripheral patch described above). The average value of the RGB values (for example, the weighted average of the RGB values, hereinafter referred to as the RGB average value 2) in the region (the same range as the above) is calculated. Then, from the plurality of calculated RGB average values 2, the RGB average value 2 whose difference from the RGB average value 1 associated with the RGB value 1 corresponding to the estimation target color is equal to or less than a predetermined threshold value is specified. The RGB value 2 acquired from the acquisition position or acquisition range corresponding to the specified RGB average value 2 is selected as the RGB value corresponding to the estimation target color. At that time, the color estimation unit 31e can specify the RGB average value 2 so that the difference between the RGB values of the RGB average value 1 and the RGB average value 2 is minimized.

The color conversion unit 31f uses the scanner profile to convert the RGB value 2 selected by the color estimation unit 31e for each estimation target color of the document into L * a * b * values. Further, the color conversion unit 31f converts the converted L * a * b * value into a CMYK value by using the printer profile, if necessary. Then, the color conversion unit 31f outputs the L * a * b * value or the CMYK value to the printer 40 (print processing unit 49).

The RGB value acquisition unit 31a, the color measurement value acquisition unit 31b, the profile creation unit 31c, the association unit 31d, the color estimation unit 31e, and the color conversion unit 31f may be configured as hardware, or the control unit 31 may be configured as hardware. RGB value acquisition unit 31a, color measurement value acquisition unit 31b, profile creation unit 31c, association unit 31d, color estimation unit 31e, color conversion unit 31f (particularly RGB value acquisition unit 31a, color measurement value acquisition unit 31b, association It may be configured as a color estimation program that functions as unit 31d and color estimation unit 31e), and the CPU 32 may execute the color estimation program.

The storage unit 35 is composed of an HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like, and is acquired by a program for the CPU 32 to control each unit, information on the processing function of the own device, and a color measurement value acquisition unit 31b. The RGB values, the color measurement values acquired by the color measurement value acquisition unit 31b, the scanner profile created by the profile creation unit 31c, the table created by the association unit 31d, and the like are stored.

The network I / F unit 36 is composed of a NIC (Network Interface Card), a modem, or the like, connects the color estimation device 30 to the communication network 70, and connects with the output instruction terminal 20, the printer 40, the scanner 50, and the colorimeter 60. Enables data communication.

The display unit 37 is an LCD (Liquid Crystal Display), an organic EL (Electro Luminescence) display, or the like, and displays various screens related to the creation of a scanner profile, color conversion of a document, and the like.

The operation unit 38 is a mouse, keyboard, hard switch, etc., and enables various operations related to creation of a scanner profile, color conversion of a document, and the like.

[Printer]
The printer 40 is an image forming apparatus such as an MFP (Multi-Functional Peripherals), and is a color chart for creating a scanner profile or a document (for example, a natural image or patch of a person or landscape) that undergoes color conversion using the scanner profile. (Chart image) whose arrangement cannot be changed) is output. As shown in FIG. 6A, the printer 40 includes a control unit 41, a storage unit 45, a network I / F unit 46, a display operation unit 47, an image processing unit 48, a print processing unit 49, and the like.

The control unit 41 is composed of a CPU 42 and a memory such as a ROM 43 or a RAM 44, and the CPU 42 controls the operation of the entire printer 40 by expanding the control program stored in the ROM 43 or the storage unit 45 into the RAM 44 and executing the control program. .. When the printer 40 has the function of the color estimation device 30, the control unit 41 also functions as a profile creation unit 41a, an association unit 41b, a color estimation unit 41c, and the like, as shown in FIG. 6B. Since the functions of the profile creation unit 41a, the association unit 41b, and the color estimation unit 41c are the same as those of the profile creation unit 31c, the association unit 31d, and the color estimation unit 31e of the color estimation device 30, the description thereof will be omitted.

The storage unit 45 is composed of an HDD, an SSD, or the like, and includes a program for the CPU 42 to control each unit, information on the processing function of the own device, a printer profile, and, if necessary, an RGB value acquired by the inline scanner 49a described later. The color measurement values acquired by the in-line colorimeter 49b, the scanner profile created by the profile creation unit 41a, the table created by the association unit 41b, and the like are stored.

The network I / F unit 46 is composed of a NIC, a modem, or the like, connects the printer 40 to the communication network 70, and enables data communication with the color estimation device 30 or the like.

The display operation unit 47 is a touch panel or the like provided with a pressure-sensitive operation unit (touch sensor) in which transparent electrodes are arranged in a grid pattern on the display unit, displays various screens related to printing processing, and performs various operations related to printing processing. To enable. When the printer 40 has the function of the color estimation device 30, the display operation unit 47 displays various screens related to the creation of the scanner profile and the color conversion of the original, and relates to the creation of the scanner profile and the color conversion of the original. Enables various operations.

The image processing unit 48 color-converts the L * a * b * values of the original into CMYK values using the printer profile created in advance. Then, the image after the color conversion is subjected to image processing (processing such as color adjustment, density adjustment, size adjustment, etc.) and screening, and the image data after the image processing is transferred to the print processing unit 49. When the printer 40 has the function of the color estimation device 30, the image processing unit 48 color-converts the RGB value of the original into the L * a * b * value by using the scanner profile created by the profile creation unit 41a. do.

The print processing unit (print engine) 49 executes the print process based on the image data after the image process. The printing processing unit 49 irradiates the photoconductor drum charged by the charging device with light corresponding to the image from the exposure device to form an electrostatic latent image, adheres the toner charged by the developing device, and develops the image. The toner image is first transferred to a transfer belt, secondarily transferred from the transfer belt to paper, and further, a process of fixing the toner image on the paper is performed by a fixing device. Further, as shown in FIG. 5, when the printer 40 has the functions of the scanner 50 and the colorimeter 60, the print processing unit 49 includes the inline scanner 49a and the inline colorimeter 49b.

The in-line scanner 49a is composed of, for example, three types of RGB sensors, and outputs RGB values acquired by the RGB sensors. The in-line scanner 49a functions as an RGB value acquisition unit when the printer 40 has the function of the color estimation device 30.

The in-line colorimeter 49b is, for example, a spectral type (spectral photometric meter) colorimeter that can measure each wavelength of light like an external colorimeter, and has a color measurement value with the same accuracy as an external colorimeter. (L * a * b * value, XYZ value, etc.) is output. The in-line colorimeter 49b functions as a color measurement value acquisition unit when the printer 40 has the function of the color estimation device 30.

4 to 6 are examples of the color estimation device 30 and the printer 40 of this embodiment, and their configurations can be changed as appropriate.

For example, when the color estimation device 30 creates a scanner profile, the color estimation device 30 serves as a controller for controlling a printer 40, a scanner 50, and a colorimeter 60 (or a printer 40 including an in-line scanner and an in-line colorimeter). If the color estimation device 30 can function and the color estimation device 30 utilizes a pre-created scanner profile (that is, does not create a scanner profile), the color estimation device 30 is a printer 50 (or a printer 40 including an in-line scanner). ) Can function as a controller to control.

Hereinafter, the operation of the color estimation device 30 (or the printer 40 having the function of the color estimation device 30) of this embodiment will be described. The CPU 32 expands the color estimation program stored in the ROM 33 or the storage unit 35 into the RAM 34 and executes it to execute the processing of each step shown in the flowcharts of FIGS. 7 to 9.

[Scanner profile creation process]
First, the procedure for creating the scanner profile will be described with reference to the flowchart of FIG. 7. In this embodiment, the color estimation device 30 creates a scanner profile and performs color conversion described later using the created scanner profile. However, a scanner profile created in advance is acquired, and the acquired scanner profile is used. Color conversion described later may be performed.

As shown in FIG. 7, the control unit 31 of the color estimation device 30 generates image data of a color chart in which patches are arranged so that information on the entire color gamut of the printer can be acquired, transmits the image data to the printer 40, and transmits the image data to the printer 40. To output a color chart (S101). At that time, the technique of Patent Document 1 may be used to output a color chart in which the patches are rearranged so that the RGB values around the patches are equalized.

Next, the control unit 31 (RGB acquisition unit 31a) acquires the RGB value (RGB value 1) of each patch of the color chart from the scanner 50 (or the in-line scanner 49a of the printer 40) (S102).

Next, the control unit 31 (color measurement value acquisition unit 31b) starts with the color measurement device 60 (or the in-line color measurement device 49b of the printer 40) to measure the color measurement values (L * a * b * values) of each patch in the color chart. ) Is acquired (S103).

Next, the control unit 31 (profile creation unit 31c) creates and stores a color conversion table (scanner profile) that associates the RGB value 1 of each patch of the chart with the color measurement value (L * a * b * value). It is stored in the unit 35 or the like (S104).

Next, the control unit 31 (correspondence unit 31d) calculates the RGB average value 1 of the peripheral patches including each patch of the color chart (S105), and stores the RGB value 1 and the RGB average value 1 in association with each other. (S106). For example, a table for associating the RGB value 1 with the RGB average value 1 is created, or the scanner profile is modified by associating the RGB value 1 of the scanner profile with the RGB average value 1. If the color chart is a color chart in which the patches are rearranged so that the RGB values around the patches are equalized, the RGB average value 1 may be stored for each chart, and in the case of a normal color chart, the RGB values may be stored. The RGB average value 1 may be stored for each patch.

[Color conversion process]
Next, the procedure for converting the RGB value of the document into the color measurement value (L * a * b * value) will be described with reference to the flowcharts of FIGS. 8 and 9.

As shown in FIG. 8, the control unit 31 (RGB acquisition unit 31a) acquires RGB values (RGB value 2) of each region of the document from the scanner 50 (or the in-line scanner 49a of the printer 40) (S201).

Next, the control unit 31 (color estimation unit 31e) estimates the RGB value of the color to be estimated of the document (S202).

FIG. 9 shows the details of this step, and the control unit 31 (color estimation unit 31e) selects an arbitrary CMYK value as the estimation target color (S301).

Next, the control unit 31 (color estimation unit 31e) determines a method for acquiring a plurality of (n) RGB values 2 and RGB average values 2 with different acquisition positions or acquisition ranges (S302). Specifically, a method of acquiring a plurality of RGB values 2 and RGB average values 2 is selected depending on whether the original is a natural image or a chart image. For example, when the original is a natural image, a plurality of RGB values 2 are acquired by changing the acquisition position or acquisition range in the object, and when the original is a chart image, the acquisition positions are shifted in order from the edge of the original to obtain a plurality of RGB values 2. Acquires RGB value 2.

Next, the control unit 31 (color estimation unit 31e) has an RGB value 2 for each of n acquisition positions or acquisition ranges, and a predetermined peripheral region including the acquisition position or acquisition range (acquired position or acquisition range as the center). A box (storage area, RGB_BOX [n] [2]) for storing the RGB average value 2 of the range area) is prepared (S303).

Next, the control unit 31 (color estimation unit 31e) executes the following steps S304 to 306 in a loop of n times. Specifically, the scan data of the original is analyzed to extract the region of the color to be estimated, and the RGB value 2 (Block_RGB) is acquired by changing the acquisition position or the acquisition range with respect to the region (S304), and the acquisition thereof is performed. The RGB average value 2 (PeripheryAve_RGB) of the peripheral region including the position or the acquisition range is acquired (S305). Then, each of the acquired data is substituted into RGB_BOX (S306). That is, Block_RGB is substituted for RGB_BOX [n] [0], and PeripheryAve_RGB is substituted for RGB_BOX [n] [1].

Next, the control unit 31 (color estimation unit 31e) refers to the table stored in the storage unit 35 or the like and the modified scanner profile to obtain the RGB average value 1 associated with the RGB value 1 corresponding to the color to be estimated. Read out, compare the RGB average value 1 with the n RGB average values 2, and specify the RGB average value 2 whose difference from the RGB average value 1 is equal to or less than a predetermined threshold (S307).

Then, the control unit 31 (color estimation unit 31e) uses the RGB value 2 acquired from the acquisition position or acquisition range corresponding to the RGB average value 2 specified in S307, and the RGB value corresponding to the estimation target color selected in S301. Is selected as (S308).

Returning to FIG. 8, the control unit 31 (color conversion unit 31f) uses the scanner profile created in S104 of FIG. 7 to obtain the RGB value (selected RGB value 2) estimated in S202 by L * a * b *. Convert to a value (S203).

Next, the control unit 31 (color conversion unit 31f) converts the L * a * b * value converted in S203 into a CMYK value using the printer profile, if necessary (S204).

Next, the control unit 31 (color conversion unit 31f) outputs the L * a * b * value converted in S203 or the CMYK value converted in S204 to the printer 40 to instruct printing (S205).

Hereinafter, the color estimation method of this embodiment will be described with reference to specific examples.

FIG. 10 is a schematic diagram illustrating the color estimation method of this embodiment. As shown on the left side of the figure, in the evaluation natural image including three objects of star shape, circle, and triangle (the difference in the color of the object is expressed by changing the type of hatching), the star shape object is Y100. In the case of% object, as shown in the "L * a * b * value" column of the table on the right side of the figure, L * a at the three acquisition positions (black circle, star, triangle) in the object. Even if the * b * values are the same, as shown in the "RGB value" column, the RGB value measured by the scanner changes due to the influence of flare. Here, the difference between the RGB value at a certain position and the RGB average value around that position is defined as the flare influence degree. If the flare impact of an object with Y100% of the scanner profile is (7,2,4), compare that value with the flare impact of each acquisition position shown in the "flare impact" column, and compare the flare impact of the scanner profile. The triangle closest to the flare influence degree is determined as the acquisition position, and the RGB value (10,240,245) at the determined acquisition position is selected as the RGB value of the Y100% object.

FIG. 11 is a schematic diagram illustrating another example of the color estimation method of this embodiment. Similar to FIG. 10, in the evaluation natural image including three objects of star shape, circle, and triangle as shown on the left side of the figure, when the star shape object is an object of Y100%, the table on the right side of the figure shows " As shown in the "L * a * b * value" column, even if the L * a * b * values in the three acquisition ranges (thin solid line, thin broken line, and thick solid line) in the object are the same value, "L * a * b * value" As shown in the "RGB value" column, the RGB value measured by the scanner changes due to the influence of flare. Here, when the flare influence degree of the scanner profile is (7,2,4), the value is compared with the flare influence degree of each acquisition range shown in the "flare influence degree" column, and the flare influence degree of the scanner profile is compared. The thick solid line closest to the degree is determined as the acquisition range, and the RGB values (10,240,245) in the determined acquisition range are selected as the RGB values of the Y100% object.

Although FIGS. 10 and 11 have described the case where the object has a uniform color (Y100%), the color may change within the object. For example, as shown in FIG. 12, when the color of the star-shaped object changes inside the object (the change in the color of the object is expressed by changing the type of hatching), the acquisition position or the acquisition range. It is preferable to set a plurality of acquisition positions or acquisition ranges from the same color area (areas having similar RGB values) in the target object.

In this way, the acquisition position or acquisition range of the RGB value of the estimation target color is determined in consideration of the influence of flare on the scanner profile, and the RGB value of the acquisition position or acquisition range is selected to obtain a natural image or patch. Colors can be estimated appropriately even for documents such as charts whose arrangement cannot be changed, and the accuracy of color conversion using the scanner profile can be improved.

The present invention is not limited to the above embodiment, and the configuration and control of the system and each device can be appropriately changed as long as the gist of the present invention is not deviated.

For example, in the above embodiment, the L * a * b * value in the CIE 1976 color space is illustrated as the color measurement value, but it may be the XYZ value in the CIE 1931 color space, or it may be used as a color appearance model such as CIECAM02. Well, there are no particular restrictions.

Further, in the above embodiment, the case where the color estimation device 30 creates the scanner profile and performs the color conversion using the scanner profile has been described, but the case where the printer 40 creates the scanner profile and performs the color conversion using the scanner profile. In the same manner, the color estimation method of the present invention can be applied.

The present invention relates to a color estimation device that estimates the color of a document in consideration of the influence of flare on a scanner profile, a color estimation method in a system including the color estimation device, a color estimation program operating in the system including the color estimation device, and a color estimation device. It can be used as a recording medium on which the color estimation program is recorded.

10 Printing system 20 Output instruction terminal 30 Color estimation device 31 Control unit 31a RGB value acquisition unit 31b Color measurement value acquisition unit 31c Profile creation unit 31d Correspondence unit 31e Color estimation unit 31f Color conversion unit 32 CPU
33 ROM
34 RAM
35 Storage unit 36 Network I / F unit 37 Display unit 38 Operation unit 40 Printer 41 Control unit 41a Profile creation unit 41b Correspondence unit 41c Color estimation unit 42 CPU
43 ROM
44 RAM
45 Storage unit 46 Network I / F unit 47 Display operation unit 48 Image processing unit 49 Print processing unit 49a In-line scanner 49b In-line colorimeter 50 Scanner 60 Colorimeter 70 Communication network

Claims (24)

The RGB value acquisition unit that acquires the first RGB value of each patch of the chart,
A color measurement value acquisition unit that acquires the color measurement value of each patch in the chart,
For each patch in the chart, the first RGB average value, which is the average of the RGB values of the peripheral patches including the patch, is calculated, and the first RGB value of each patch and the first RGB average value are stored in association with each other. With the patch
It is equipped with a color estimation unit that estimates the RGB values of each target color of the document.
The RGB value acquisition unit acquires a plurality of second RGB values whose positions or ranges are changed within the region of each target color of the document.
For each of the target colors, the color estimation unit calculates a second RGB average value which is an average of the RGB values of the peripheral region including the position or range where the second RGB value is acquired, and the calculated second RGB values. From the average values, the second RGB average value whose difference from the first RGB average value associated with the first RGB value corresponding to the target color is equal to or less than a predetermined threshold is specified, and the specified second RGB average is specified. The second RGB value acquired from the position or range corresponding to the value is selected as the RGB value of the target color.
A color estimation device characterized by the fact that. A profile creation unit that creates a scanner profile that associates the first RGB value with the color measurement value,
A color conversion unit that converts the second RGB value selected as the RGB value of each target color of the document into the color measurement value by using the scanner profile is further provided.
The color estimation device according to claim 1. The color estimation unit specifies the second RGB average value so that the difference between the first RGB average value and the second RGB average value is minimized.
The color estimation device according to claim 1 or 2. The chart is a chart in which patches are rearranged so that the first RGB average value becomes a constant value in the chart.
The association unit stores the first RGB average value for each chart.
The color estimation device according to any one of claims 1 to 3, wherein the color estimation device is characterized. The association unit stores the first RGB average value for each patch.
The color estimation device according to any one of claims 1 to 3, wherein the color estimation device is characterized. The RGB value acquisition unit switches a method of acquiring a plurality of the second RGB values depending on whether the original is a natural image or a chart image.
The color estimation device according to any one of claims 1 to 5, wherein the color estimation device is characterized. When acquiring the second RGB value from the original, the RGB value acquisition unit searches for all positions or ranges in which an area equal to or larger than the minimum reading size can be secured.
The color estimation device according to any one of claims 1 to 6, wherein the color estimation device is characterized. The RGB value acquisition unit divides a region of each target color of the document so that the second RGB value can be acquired by the reading size when the first RGB value is acquired from the chart.
The color estimation device according to any one of claims 1 to 7, wherein the color estimation device is characterized. A color estimation method in a system that estimates the RGB values of each target color of a document.
The first acquisition process to acquire the first RGB value of each patch of the chart, and
The second acquisition process for acquiring the color measurement value of each patch in the chart, and
For each patch in the chart, the first RGB average value, which is the average of the RGB values of the peripheral patches including the patch, is calculated, and the first RGB value of each patch and the first RGB average value are stored in association with each other. With the patching process
A third acquisition process for acquiring a plurality of second RGB values whose positions or ranges are changed within the area of each target color of the document, and
For each of the target colors, the second RGB average value, which is the average of the RGB values of the peripheral region including the position or range where the second RGB value was acquired, was calculated, and the calculated second RGB average value was selected from among the plurality of calculated second RGB average values. The second RGB average value whose difference from the first RGB average value associated with the first RGB value corresponding to the target color is equal to or less than a predetermined threshold is specified, and the position corresponding to the specified second RGB average value or A color estimation process of selecting the second RGB value acquired from the range as the RGB value of the target color is executed.
A color estimation method characterized by that. A profile creation process for creating a scanner profile that associates the first RGB value with the color measurement value,
Using the scanner profile, a color conversion process for converting the second RGB value selected as the RGB value of each target color of the document into the color measurement value is further executed.
The color estimation method according to claim 9. In the color estimation process, the second RGB average value is specified so that the difference between the first RGB average value and the second RGB average value is minimized.
The color estimation method according to claim 9 or 10. The chart is a chart in which patches are rearranged so that the first RGB average value becomes a constant value in the chart.
In the association process, the first RGB average value is stored for each chart.
The color estimation method according to any one of claims 9 to 11, wherein the color estimation method is characterized. In the association process, the first RGB average value is stored for each patch.
The color estimation method according to any one of claims 9 to 11, wherein the color estimation method is characterized. In the third acquisition process, the method of acquiring a plurality of the second RGB values is switched depending on whether the original is a natural image or a chart image.
The color estimation method according to any one of claims 9 to 13, wherein the color estimation method is characterized. In the third acquisition process, when acquiring the second RGB value from the document, all positions or ranges that can secure an area equal to or larger than the minimum reading size are searched for.
The color estimation method according to any one of claims 9 to 14, characterized in that. In the third acquisition process, the region of each target color of the document is divided so that the second RGB value can be acquired by the reading size when the first RGB value is acquired from the chart.
The color estimation method according to any one of claims 9 to 15, characterized in that. A color estimation program operated by a device in the system that estimates the RGB values of each target color of the document.
In the device
First acquisition process to acquire the first RGB value of each patch in the chart,
The second acquisition process of acquiring the color measurement value of each patch in the chart,
For each patch in the chart, the first RGB average value, which is the average of the RGB values of the peripheral patches including the patch, is calculated, and the first RGB value of each patch and the first RGB average value are stored in association with each other. Patching process,
A third acquisition process for acquiring a plurality of second RGB values whose positions or ranges are changed within the area of each target color of the document.
For each of the target colors, the second RGB average value, which is the average of the RGB values of the peripheral region including the position or range where the second RGB value was acquired, was calculated, and the calculated second RGB average value was selected from among the plurality of calculated second RGB average values. The second RGB average value whose difference from the first RGB average value associated with the first RGB value corresponding to the target color is equal to or less than a predetermined threshold is specified, and the position corresponding to the specified second RGB average value or A color estimation process of selecting the second RGB value acquired from the range as the RGB value of the target color is executed.
A color estimation program characterized by that. In addition to the device
A profile creation process for creating a scanner profile that associates the first RGB value with the color measurement value.
Using the scanner profile, a color conversion process for converting the second RGB value selected as the RGB value of each target color of the document into the color measurement value is executed.
The color estimation program according to claim 17. In the color estimation process, the second RGB average value is specified so that the difference between the first RGB average value and the second RGB average value is minimized.
The color estimation program according to claim 17 or 18. The chart is a chart in which patches are rearranged so that the first RGB average value becomes a constant value in the chart.
In the association process, the first RGB average value is stored for each chart.
The color estimation program according to any one of claims 17 to 19, wherein the color estimation program is characterized. In the association process, the first RGB average value is stored for each patch.
The color estimation program according to any one of claims 17 to 19, wherein the color estimation program is characterized. In the third acquisition process, the method of acquiring a plurality of the second RGB values is switched depending on whether the original is a natural image or a chart image.
The color estimation program according to any one of claims 17 to 21, characterized in that. In the third acquisition process, when acquiring the second RGB value from the document, all positions or ranges that can secure an area equal to or larger than the minimum reading size are searched for.
The color estimation program according to any one of claims 17 to 22, wherein the color estimation program is characterized. In the third acquisition process, the region of each target color of the document is divided so that the second RGB value can be acquired by the reading size when the first RGB value is acquired from the chart.
The color estimation program according to any one of claims 17 to 23.

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