JPH11331622A - Image data configuration method, its device, image data conversion method, its device and image data conversion system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the user to view a same image on each device without loss of a color in the case of displaying image data among the devices whose reproducible color space differs such as a print image and an image displayed on a CRT. SOLUTION: In the case of converting RGB data read from a print into SRGB data for being displayed on a CRT, the SRGB data consist of image data in a color reproduction area that are displayed on the CRT and of image data at the outside of the color reproduction area that cannot be displayed on the CRT. In order to display an image on the CRT, the image data in the color reproduction area are in use and the SRGB data are processed and edited, and in the case of converting the SRGB data into RGB data, both the image data in the color reproduction area and the image data at the outside of the color reproduction area are used to convert the SRGB data into the RGB data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for constructing or converting image data so as to reproduce an image without loss of color information even between devices having different color reproduction ranges, and an image data conversion method. And an image data conversion system.

[0002]

2. Description of the Related Art A hard copy image reproduced by a printer device such as a film or a photograph is read by a scanner or the like and provided to a user as digital image data, or digital image data obtained by a user with a digital camera or the like is printed. Such a hard copy image is provided to a user. The digital image data provided to the user or obtained by the digital camera is stored in a C
The image can be displayed on an RT or a liquid crystal monitor and observed as a soft copy image. In addition, there is provided a service in which the user displays the provided digital image data on a CRT or the like, performs processing such as adding characters and symbols thereto, and reproduces the processed digital image data again as a hard copy image. I have.

[0003] In such a service, digital image data obtained by reading a hard copy image is, for example, a flat image proposed by Eastman Kodak Company.
It is hierarchized so as to have a format defined by the shPix standard, color-converted into an S-RGB space defined by the FlashPix standard, compressed, recorded on a medium such as a CD-R, or recorded on a network. Is provided to the user via. Also, the digital image data can be converted to a standard called Photo-YCC and provided to the user. Where S
-RGB is a color standard of image data displayed on a CRT, and "converting to S-RGB space" means a process of performing color conversion so that image data output from a medium is displayed best when displayed on a CRT. It is.

Here, in a system for obtaining digital image data from a hard copy image such as a print and reproducing it as a soft copy image such as a CRT, or reproducing digital image data reproduced as a soft copy image as a hard copy image. In order to enable digital image data to be reproduced well in a device such as a printer or a CRT, the perceived color appearance in a hard copy image and a soft copy image displayed on both devices based on the same image information. The color of the image is mutually converted so that is equal, and even if the converted image (image data) is restored to the original device image (image data) again by performing some processing on the converted image (image data). Both image data can be made to have almost the same color appearance as How to create a color conversion lookup table representing a correspondence between it has been proposed by the present applicant (Japanese Patent Application No. 9-265334).

A color conversion lookup table created by this method has a brightness range of an image which can be displayed by a device such as a printer (hereinafter referred to as a printer device).
A dynamic range correction function for converting the dynamic range of the image data of the printer device into the dynamic range of the CRT device so that the brightness range of the image that can be displayed by the RT device is substantially equivalent to the image displayed on the CRT device; So that the perceived color appearance between the image and the image displayed on the printer device is equal.
For example, it has a color conversion function of converting image data of a printer device into image data of a CRT device in accordance with a color adaptation model based on Von Kries' color adaptation rule. According to such a color conversion look-up table, data conversion is performed in accordance with the color adaptation model. Therefore, it is basically possible to perform data conversion such that the color appearance of both images is the same. it can. In addition, the dynamic range is corrected (or inversely corrected) together with the data conversion according to the color adaptation model.
Even between such media having a different dynamic range between the image of the non-light emitting display medium and the image of the light emitting display medium,
Data conversion can be performed without wasting the wider range.

On the other hand, as described above, digital image data obtained by reading from a hard copy image is:
In a special case such as when used by an expert, the data is high-resolution data of 8 bits or more. Digital image data converted into the S-RGB space provided to the user in the above-described service is usually RGB. Provided as 8-bit data for each color. Therefore, when this digital image data is reproduced on a CRT, only the colors represented by the data having the RGB values of 0 to 255 are reproduced. However, depending on the color space, the color gamut reproduced by the printer device may be wider than the color gamut reproduced by the CRT. Also, the color gamut of a scene actually seen by humans is CRT
Wider than the color gamut of.

For this reason, when the original image data is converted into the S-RGB space in the service as described above, the color reproducible in the printer device becomes the S-R color.
Missing due to conversion to GB space. in this way,
Even if the color is missing, the digital image data converted to the S-RGB space can be reproduced on the printer device because the CRT can reproduce only the color in the reproduction range where the color was originally missing. It can be reproduced so that it looks like a thing. However, when a user processes digital image data and reproduces the processed digital image data as a hard copy image in a printer, information about colors contained in the original image data is lost. In the hard copy image, the reproduced color cannot be reproduced.

In order to solve this problem, at the expense of matching the appearance of the hardcopy image with the appearance of the image displayed on the CRT, all or part of the image can be obtained without following the strict definition of the color space. (Method 1) in which the original color image data is converted into S-RGB digital image data in which data outside the color gamut of the CRT (for example, a data value of -10 to 258) is recognized. The digital image data is further compressed to 8 bits with reference to a one-dimensional look-up table, and (0
A data value of .about.255), attaching a compression profile representing this one-dimensional lookup table to the compressed data, and decompressing the compressed digital image data with reference to the compression profile at the time of CRT display or printing. (Method 2), a method of allocating digital image data to a range wider than 8 bits using the above-described Photo-YCC standard (method 3), and a method of using data of 8 bits or more (method 4) have been proposed. ing.

[0009]

However, in the above-mentioned method 1, the S
-Digital image data is reproduced without converting the image data in the RGB space to the image data in the S-RGB space and converting the image data in the S-RGB space to the image data of the printer device. And C
The color appearance with the image displayed on the RT does not match, and the distortion of the color space differs depending on the type of the printer device or CRT or the type of the photosensitive material to be printed. For this reason, there is no versatility, and when the color space is partially distorted, it is necessary to consider how to determine the bit resolution of the distorted color space for each distortion method,
Processing becomes complicated.

In the above method 2, the above-mentioned problem can be solved by a relatively simple structure. However, the above-mentioned method of FlashPix standard (core 1.0) data is used.
Since a function cannot define an arbitrary one-dimensional look-up table, this method cannot be employed when using FlashPix standard (core 1.0) data. Further, since the range of data to be compressed and the compression profile differ depending on the device, it is necessary to prepare a one-dimensional lookup table for each device, and there is no versatility. Further, since the data is compressed to 8 bits, the bit resolution when decompressing the data may be reduced. Furthermore, since it is necessary to decompress the digital image data by referring to the compression profile every time the compressed digital image data is reproduced on the CRT, it takes a long time to display the image on the CRT.

Further, in the above method 3, since the 8-bit image data is allocated to a range wider than 8 bits, the bit resolution of the displayed image may be reduced, and the digital image data may be transferred to the CRT. Since it is necessary to perform a matrix operation for conversion from YCC to RGB each time it is displayed, it takes a long time to display an image on a CRT.

Further, in the above method 4, CR
Since it is necessary to perform an operation of converting digital image data into 8-bit data when displaying on T, it takes a long time to display an image on a CRT.

The present invention has been made in view of the above circumstances, and forms image data that can be displayed on another device with versatility without losing colors reproduced in a device such as a printer. It is an object of the present invention to provide an image data configuration method and apparatus, an image data conversion method and apparatus for converting image data, and an image data conversion system.

[0014]

An image data forming method according to the present invention is a method for forming device image data corresponding to the color reproduction characteristics of a device for reproducing color image data. At least one out-of-color-gamut image data that cannot be reproduced by the device is attached to possible color-gamut image data, and the device image data is composed of the color-gamut image data and the out-of-color-gamut image data. It is characterized by the following.

Here, the "image data within the color gamut" refers to
For example, if the device can reproduce 8-bit data,
The term "image data having a data value in the range of 0 to 255" refers to image data having a data value of 0 or less or 255 or more.

In the image data forming method according to the present invention, the device image data may be configured such that the in-color gamut image data and the out-of-color gamut image data are stored in separate files. Good.

Further, the device image data may be configured so that the in-color gamut image data and the out-of-color gamut image data are stored in the same file.

Here, "to store the image data within the color gamut and the image data outside the color gamut in the same file" means:
For example, it means that files are hierarchized so as to have a format defined by the FlashPix standard, and image data within the color gamut and image data outside the color gamut are stored in each layer.

Further, the bit resolution of the image data outside the color gamut may be larger than the bit resolution of the image data inside the color gamut.

Here, "the bit resolution of the image data outside the color gamut is larger than the bit resolution of the image data inside the color gamut" means, for example, that the image data outside the color gamut is 16-bit data and the image data inside the color gamut is This means that the data is 8-bit data. Further, "the bit resolution of the image data outside the color gamut and the bit resolution of the image data inside the color gamut are the same" means, for example, that both the image data outside the color gamut and the image data inside the color gamut are 8-bit data. Say.

Further, the bit resolution of the image data outside the color gamut and the bit resolution of the image data inside the color gamut may be the same.

Further, the in-color gamut image data and / or the out-of-color gamut image data may be compressed. When both of them are compressed, the in-color gamut image data and the out-of-color gamut image data are compressed. The format may be different.

Further, the image data outside the color gamut has first data data outside the color gamut having a data value equal to or less than the minimum value of the image data inside the color gamut, and data having a data value equal to or more than the maximum value of the image data inside the color gamut. And the second out-of-gamut image data having a value, the first and second out-of-gamut image data are combined with one out-of-gamut image data having a predetermined bit resolution to produce a combined out-of-gamut image. It is preferable to obtain data, arrange the data values of the out-of-color-gamut image data in a plane-sequential manner, and compress the data in a lossless compression format.

Here, the "data value equal to or less than the minimum value of the image data within the color reproduction range" is, for example, a value of 0 or less when the image data within the color reproduction range is 8-bit data having a data value of 0 to 255. Means The “data value equal to or greater than the maximum value of the image data within the color gamut” means a value equal to or greater than 255 when the image data within the color gamut is 8-bit data. Further, "arrange the data values of the out-of-combined-color-reproduction-gamut image data in a frame-sequential manner" means that data of three colors of RGB are alternately arranged in the order of R, G, B,.
R, R, R, R, R
.., G, G, G, G, G... The “lossless compression format” refers to a compression format such as run-length compression and Huffman compression that can compress image data outside the composite color reproduction range without losing data.

Further, the image data outside the color gamut has first data data outside the color gamut having a data value equal to or less than the minimum value of the image data inside the color gamut, and data having a data value equal to or more than the maximum value of the image data inside the color gamut. When the image data is composed of the second out-of-color-gamut image data having the
And converting the second out-of-gamut image data to obtain first and second converted out-of-gamut image data, and converting the first and second out-of-gamut image data into the in-gamut image data. It is preferable to perform compression in the same compression format.

S1 '= S1-Smax S2' = Smax- (S2min-S2) where S1: first out-of-gamut image data S2: second out-of-gamut image data S1 ': first converted color reproduction Out-of-gamut image data S2 ': Second converted color gamut image data Smax: Maximum value that can be taken by color gamut image data S2min: Any value that can be taken by second out-of-color gamut image data The data may include other device image data corresponding to the color reproduction characteristics of another device different from the device.

An image data forming apparatus according to the present invention is an image data forming apparatus for forming device image data corresponding to the color reproduction characteristics of a device for reproducing color image data. Means for attaching to the data one or more out-of-gamut image data that cannot be reproduced by the device; and data-constructing means for configuring the device image data with the in-gamut image data and the out-of-gamut image data. It is characterized by having.

[0028] The data structuring means may be means for structuring the device image data such that the in-color gamut image data and the out-of-color gamut image data are stored in separate files.

Further, the data configuration means may be means for configuring the device image data such that the in-color gamut image data and the out-of-color gamut image data are stored in the same file.

Further, the data configuration means may be means for configuring the device image data such that a bit resolution of the image data outside the color gamut is larger than a bit resolution of the image data within the color gamut. .

Further, the data configuration means may be means for configuring the device image data so that the bit resolution of the image data outside the color gamut and the bit resolution of the image data within the color gamut are the same. Good.

Further, the data forming means may be means for forming the device image data by compressing the image data in the color gamut and / or the image data outside the color gamut. Means for configuring the device image data so that the compression format of the in-color gamut image data and the out-of-color gamut image data is different.

In the image data forming apparatus according to the present invention, the out-of-color-gamut image data has a data value equal to or less than the minimum value of the in-gamut image data. When the image data is composed of the second out-of-gamut image data having a data value equal to or greater than the maximum value of the in-gamut image data, the data forming means converts the first and second out-of-gamut image data into ones of a predetermined bit resolution Combining means for obtaining combined out-of-gamut image data by combining the two out-of-gamut image data, and compressing means for arranging the data values of the combined out-of-gamut image data in a plane-sequential manner and compressing them in a lossless compression format. It is preferable to have one.

Further, in the image data forming apparatus according to the present invention, the out-of-color-gamut image data has a data value equal to or less than the minimum value of the in-color-gamut image data; When the image data is composed of the second out-of-gamut image data having a data value equal to or greater than the maximum value of the in-gamut image data, the data forming means converts the first and second out-of-gamut image data by the following operation. And the first
Converting means for obtaining image data outside the color gamut and second converted color gamut image data;
It is preferable that the image processing apparatus further includes a compression unit that compresses the image data in the color gamut using the same compression format.

S1 '= S1-Smax S2' = Smax- (S2min-S2) where S1: first out-of-gamut image data S2: second out-of-gamut image data S1 ': first converted color reproduction Out-of-gamut image data S2 ': Second converted color gamut image data Smax: Maximum value that can be taken by color gamut image data S2min: Any value that can be taken by second color gamut image data In the constituent device, the out-of-color-gamut image data may include other device image data corresponding to the color-reproduction characteristics of another device different from the device.

A first image data conversion method according to the present invention converts other device image data corresponding to the color reproduction characteristics of another device different from the device so as to correspond to the color reproduction characteristics of the device. Obtaining the converted image data, dividing the converted image data into the image data within the color gamut and the image data outside the color gamut, and obtaining the device image data by the image data configuration method according to the present invention. is there.

[0037] In a second image data conversion method according to the present invention, the device image data obtained by the image data composing method according to the present invention is obtained by converting another image data corresponding to the color reproduction characteristics of another device different from the device. It is characterized by conversion into device image data.

Image data conversion method.

A first image data converter according to the present invention converts other device image data corresponding to the color reproduction characteristics of another device different from the device so as to correspond to the color reproduction characteristics of the device. Means for converting the converted image data into the in-color gamut image data and the out-of-color gamut image data, and an image data forming apparatus according to the present invention. It is assumed that.

A second image data conversion device according to the present invention includes an image data forming device according to the present invention, and a device which converts the device image data obtained by the image data forming device into a color reproduction characteristic of another device different from the device. And color reverse conversion means for converting the image data into another device image data corresponding to.

The image data conversion system according to the present invention comprises:
A first image data conversion device according to the present invention, the device, and the device image data obtained by the image data configuration device, the device image data corresponding to the color reproduction characteristics of another device different from the device; And the other device.

[0042]

According to the present invention, device image data is composed of image data within the color gamut reproducible in the device and image data outside the color gamut unreproducible in the device. Therefore, device image data (hereinafter, referred to as first device image data) of one device (hereinafter, referred to as first device) is device image data (second device image data) of another device (hereinafter, referred to as second device). When the first device and the second device have different color gamut when converting to, the first device image data is converted to be reproducible by the second device,
The converted image data is divided into in-gamut image data reproducible in the second device and out-of-gamut image data that cannot be reproduced in the second device. Of the device image data.

By configuring the device image data in this manner, even if the first device and the second device have different color reproduction ranges, the color is lost without distorting the color space of the image data. Second without
Since the device image data of the first and second devices can be configured, when the second device image data is further converted to the first device image data, an unreproducible color space does not occur. Can be prevented from being inconsistent. Further, since it is not necessary to distort the color, it is not necessary to consider how to distort the color or the bit resolution for each device, and it is possible to convert image data with versatility.

Further, since it is not necessary to compress the device image data to the number of bits reproducible in the second device, it is necessary to convert the second device image data into the first device image data with reference to the compression profile. This eliminates the need for a compression profile according to the device, and allows image data to be converted with versatility. Furthermore, since it is not necessary to compress the number of bits of the device image data, the bit resolution when reproducing the device image data is reduced, and when displaying the device image data, the device image data is referred to a compression profile. Thus, the device image data can be quickly reproduced because it is not necessary to perform the conversion.

Furthermore, unlike the case of using PhotoYCC, it is not necessary to perform a matrix operation, so that device image data can be quickly converted or displayed.

By storing the image data within the color gamut and the image data outside the color gamut in the same file,
The file configuration of the device image data can be simplified, the handling of the device image data can be facilitated, and the compression efficiency when compressing the device image data can be improved.

Further, by making the bit resolution of the image data outside the color gamut larger than the bit resolution of the image data inside the color gamut, a wide color space can be allocated to the image data outside the color gamut. The image data of the area can also be held as device image data. Therefore, the device image data can be converted to correspond to the color gamut of any other device.

Further, the image data outside the color gamut is the first image data.
When the image data is composed of the second color gamut image data and the second color gamut image data, the file structure can be simplified, and the compression efficiency when the device image data is compressed can be improved. be able to.

Further, by performing an operation as shown in the above equation (1) on image data outside the color gamut, especially the JPEG
The out-of-color-gamut image data can be converted to be suitable for the compression format.

Further, by making the out-of-color-gamut image data correspond to the color-reproduction characteristics of other device image data different from the device, the color-reproducibility is reduced when the other device image data is converted to device image data. It is not necessary to convert other device image data that is out-of-range image data, so that the calculation for the conversion can be performed at high speed.

[0051]

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a schematic block diagram showing a configuration of an image data conversion system including an image data configuration device according to a first embodiment of the present invention, and FIG. 2 is a block diagram of the first embodiment. It is a schematic block diagram which shows the process performed. As shown in FIG. 1, the image data conversion system according to the present embodiment uses printing RGB data (hereinafter simply referred to as R
Image data converting means 1 for converting image data (hereinafter referred to as GB data) into 8-bit CRT image data (hereinafter referred to as SRGB data) with reference to a color order conversion look-up table (LUT) 2; Means for converting image data into RGB data with reference to a color inverse conversion look-up table (LUT) 4, a digital photographic lab machine input unit 6, lab machine output unit setup units 7, 8,
It comprises a digital lab output unit 9, a CRT 10 and a printer 11.

Color order conversion LUT2 and color inverse conversion LUT4
Is created by the color conversion look-up table creation method described in Japanese Patent Application No. 9-265334, so that the image to be printed and the image to be displayed on the CRT 10 have the same appearance. To the RGB data and the RG respectively.
In addition to the conversion into the B data, the dynamic range can be corrected. Even when the dynamic range between the image printed on the printer 11 and the image displayed on the CRT 10 is different, the wider range is wasted. It is possible to perform data conversion without any change. Note that the color order conversion LUT 2 and the color inverse conversion LUT
Reference numeral 4 is for converting each color of RGB, so that it is a three-dimensional lookup table. Also, the color order conversion L
UT2 has 0 reproducible in 8-bit image data.
In order to be able to output image data outside the color reproduction range of the CRT 10 having a data value outside the range of .about.255, that is, a data value whose value is 0 or less and 255 or more, the CRT 10 has characteristics as shown in FIG. ing. Further, the color inverse conversion LUT 4 is 0 or less and 25 in SRGB data.
It has characteristics as shown in FIG. 4 so that five or more data can be converted.

The image data conversion means 1 includes a color order conversion LUT
2, the RGB data is converted into 8-bit SRGB data. Here, the SRGB data is obtained by being divided into image data within the color gamut having data values in the range of 0 to 255, and two image data outside the color gamut having data values of 0 or less and 255 or more. The out-of-gamut image data of 0 or less is 8-bit data having a data value in the range of -255 to 0, and the out-of-gamut image data of 255 or more is 8-bit data having a data value in the range of 255 to 510. Obtained as data. Then, the image data within the color gamut is JEPG-compressed, and the two image data outside the color gamut are compressed by various compression methods including JPEG compression.
It is stored in one file as layered image data of the FlashPix standard, and this is set as SRGB data. At this time, the two out-of-color-gamut image data are
Figure 2 shows the extension in the shPix standard file.
As shown in (1), they are stored as Extension image data 1 and Extension image data 2. Also, SRG
When displaying the B data on the CRT 10, JPEG-compressed image data in the color gamut is used.

The image data inverse conversion means 3 decompresses the image data within the color gamut of the SRGB data by JPEG, decompresses the image data outside the color gamut by a decompression method corresponding to the compression method, and further decompresses the image data within the color gamut. The data and the image data outside the color gamut are added, and the added image data is converted to RGB data with reference to the color inverse conversion LUT 4.

Here, as a method of compressing the image data outside the color gamut, JPEG is used similarly to the image data inside the color gamut.
In addition to compression, various compression methods such as lossless compression such as run-length compression and Huffman compression, and lossy compression can be used. Here, when performing lossless compression, efficient compression can be performed by arranging out-of-color-gamut image data in a frame-sequential manner (arranging the same color continuously). Further, since the data amount of the image data outside the color gamut is relatively small as compared with the image data inside the color gamut, the data amount of the compressed image data outside the color gamut is very small. For this reason, the data amount of the SRGB data does not become so large even if it is composed of the image data within the color gamut and the image data outside the color gamut.

When the out-of-gamut image data is JPEG-compressed, the out-of-gamut image data having a data value of 255 or more is (data value-255).
Is applied to the out-of-color-gamut image data having a data value of 0 or less, and the operation of 255- (0-data value) is performed, and 8-bit data represented by a value of 0 to 255 (unsigned char type) It is preferable to make the data appropriate for JPEG compression. The calculation for making the image data outside the color gamut suitable for JPEG compression is not limited to the above, and various methods can be applied.

Next, the operation of the first embodiment will be described.

A film photographed by a camera or the like is set in the digital photographic lab machine input section 6 and subjected to predetermined processing such as development processing. Then, the lab machine output section setup section 7 converts the film into RGB data. Is output. Also,
Image data from an electronic image medium such as an electronic camera or FD (floppy disk) is input to the setup unit 8 for the lab machine output unit, and is converted into RGB data and output like a film. These RGB data are sent to the digital photo lab machine output unit 9 and printed out by the printer 11.

On the other hand, the RGB data is also sent to the image data conversion means 1, where the RGB data is converted to the SR data by referring to the color order conversion LUT 2 having the characteristics shown in FIG.
It is converted to GB data. The converted SRGB data includes image data within the color gamut having data values of 0 to 255 reproducible on the CRT 10 and 0 or less and 25 or less.
It consists of two out-of-color-gamut image data each having a data value of 5 or more. The image data within the color gamut is J
EPG-compressed and out-of-gamut image data are compressed by the various compression methods described above, and the compressed in-gamut image data and out-of-gamut image data are
It is stored in one file according to the shPix standard. The SRGB data is sent to the CRT 10,
Image data within the color gamut of the SRGB data is displayed on the CRT 10 as a visible image. The converted SRGB data can be recorded on a floppy disk or the like, provided to the user, and displayed on a CRT such as a personal computer of the user. Then, the user performs processing such as inputting characters to the image displayed on the CRT 10, and inputs the processed SRGB data to the image data reverse conversion unit 3. Also, SRG
If the B data is provided stored on a floppy disk or the like, the SRGB stored on the floppy disk
The data is input to the image data inverse conversion means 3. The processed SRGB data input to the image data inverse conversion means 3 is obtained by adding the processed image data in the color gamut and the image data outside the color gamut, and further referring to the color inverse conversion LUT 4 to convert the SRGB data. It is converted to RGB data. R
The GB data is sent to the digital photo lab machine output unit 9 and printed out by the printer 11.

As described above, in the first embodiment, when converting the RGB data into the SRGB data, the SRGB data is converted into the color reproduction gamut image data reproducible on the CRT 10 and the color reproduction gamut image data unreproducible on the CRT 10. When displaying an image on the CRT 10, the image data within the color gamut is used, and after processing and editing of the SRGB data, the image data within the color gamut and the image data outside the color gamut are used.
The RGB data is converted into RGB data. Therefore, even when the printer 11 and the CRT 10 have different color gamut, and the printer 11 has a wider color gamut than the CRT 10, image data outside the color gamut can be obtained without distorting the color space. This is included in the SRGB data as image data outside the color gamut. Therefore, by adding the in-color gamut image data and the out-of-color gamut image data and converting the RGB data into RGB data, it is possible to reproduce an image in the printer 11 without dropping colors from the original RGB data. This makes it possible to match the appearance of the image on the CRT 10 with the appearance of the image obtained by printing the RGB data converted from the SRGB data. Further, since there is no need to compress the SRGB data by using a compression profile specific to the device, a versatile system can be constructed.

Second Embodiment Next, a second embodiment of the present invention will be described. FIG. 5 is a schematic block diagram illustrating processing performed in an image data conversion system including an image data configuration device according to the second embodiment of the present invention. Note that the configuration of the image data conversion system is the same as the configuration of the image data conversion system shown in FIG. 1, and a detailed description thereof will be omitted. Second
The third embodiment is different from the first embodiment in that the out-of-color-gamut image data in the SRGB data is one data.

That is, in an environment (observation light source) specified in a service that converts data read from a print or the like into SRGB data and provides the data to a user, the SR
It has been confirmed by experiments by the present applicant that if the data value of the GB data is -186 to 326, the object color can be sufficiently reproduced. For this reason, the number of data is 186 for a data value of 0 or less, and 71 for a data value of 255 or more. Therefore, the data numbers of the two out-of-color-gamut image data can be summed up to be approximately 255. it can. Therefore, the two out-of-color-gamut image data in the first embodiment can be combined as one out-of-gamut image data, whereby the file structure of the SRGB data can be simplified and the compression ratio can be reduced. As a result, the file capacity of the SRGB data can be reduced.

The image data outside the color gamut is set to -3276.
It may be 16-bit signed short type data having a value of 8-32768. As described above, by setting the number of bits of the color gamut image data to 16 bits, the color gamut image data including even the colors of the scene can be included in the SRGB data.

Further, the image data outside the color gamut is -128.
It may be char type 8-bit data taking data values of ~ 127.

Third Embodiment Next, a third embodiment of the present invention will be described. FIG. 6 is a schematic block diagram illustrating processing performed in an image data conversion system including an image data configuration device according to the third embodiment of the present invention. Note that the configuration of the image data conversion system is the same as the configuration of the image data conversion system shown in FIG. 1, and a detailed description thereof will be omitted. Third
According to the first embodiment, when converting RGB data to SRGB data, the RGB data that is the image data outside the color gamut in the RGB data is not included in the RGB data together with the image data inside the color gamut without converting. This is different from the embodiment.

In this case, the RGB data is converted to a color order conversion LUT.
2, the data value of the RGB data corresponding to the image data within the color gamut of the CRT 10 is set to 0, and the data value corresponding to the image data outside the color gamut is unchanged as F.
The RGB data corresponding to the image data in the color gamut of the CRT 10 and the RGB data corresponding to the image data out of the color gamut are written in the extension of the file of the flashPix standard, and the RGB data is formed. Also, like this, SRGB
Even if the data is configured, the data used for displaying the image on the CRT 10 is only the image data within the color gamut of the SRGB data, so that the display of the image on the CRT 10 does not hinder at all.

As described above, the RGB data which is the image data outside the color gamut in the RGB data is included in the SRGB data together with the image data within the color gamut without being converted, so that the image data conversion means 1 and the image data inverse conversion means 3 Can reduce the calculation time for conversion.

In the first to third embodiments, the image data outside the color gamut is compressed. However, since the image data outside the color gamut has a relatively small number of data as described above, it is particularly compressed. It is not necessary.

In the first to third embodiments, the image data within the color gamut and the image data outside the color gamut are stored in one file of the FlashPix standard, but are stored in separate files. Is also good.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram illustrating a configuration of an image data conversion system including an image data configuration device according to a first embodiment of the present invention.

FIG. 2 is a schematic block diagram illustrating processing performed in the first embodiment.

FIG. 3 is a diagram showing characteristics of a color order conversion LUT.

FIG. 4 is a diagram showing characteristics of a color inversion LUT;

FIG. 5 is a schematic block diagram illustrating processing performed in a second embodiment.

FIG. 6 is a schematic block diagram illustrating processing performed in a third embodiment.

[Description of Signs] 1 Image data conversion means 2 Color forward conversion LUT 3 Image data reverse conversion means 4 Color reverse conversion LUT 6 Digital photo lab machine input unit 7, 8 Lab unit output unit setup unit 9 Digital photo lab unit output unit 10 CRT 11 printer

Claims (33)

[Claims] 1. An image data forming method for forming device image data corresponding to the color reproduction characteristics of a device that reproduces color image data, comprising: reproducing image data within a color reproduction range reproducible by the device; An image data forming method, comprising: attaching one or more out-of-color-gamut image data that is not possible; and forming the device image data from the in-color-gamut image data and the out-of-color-gamut image data. 2. The image data according to claim 1, wherein the device image data is configured such that the image data within the color gamut and the image data outside the color gamut are stored in separate files. Configuration method. 3. The image data configuration according to claim 1, wherein the device image data is configured such that the image data within the color gamut and the image data outside the color gamut are stored in the same file. Method. 4. The method according to claim 1, wherein a bit resolution of the image data outside the color gamut is larger than a bit resolution of the image data inside the color gamut. 5. The image processing apparatus according to claim 1, wherein the bit resolution of the image data outside the color gamut and the bit resolution of the image data inside the color gamut are the same.
Image data configuration method described in the section. 6. The method according to claim 1, wherein the in-color-gamut image data is compressed. 7. The method according to claim 1, wherein the out-of-color-gamut image data is compressed. 8. The method according to claim 6, wherein the out-of-color-gamut image data is compressed. 9. The method according to claim 8, wherein the compression format of the image data within the color gamut and the image data outside the color gamut are different. 10. The image data outside the color gamut, the first image data outside the color gamut having a data value less than the minimum value of the image data inside the color gamut, and the data not less than the maximum value of the image data inside the color gamut. And the second out-of-gamut image data having a value, the first and second out-of-gamut image data are combined with one out-of-gamut image data having a predetermined bit resolution to produce a combined out-of-gamut image. 10. The method according to claim 8, wherein data is obtained, and data values of the out-of-color-gamut image data are arranged in a frame-sequential manner and compressed in a lossless compression format. 11. The first out-of-color-gamut image data having a data value equal to or less than the minimum value of the in-color-gamut image data, and the data having a data value equal to or greater than the maximum value of the in-color-gamut image data. And the second out-of-color-gamut image data having the values, the first and second out-of-gamut image data are converted by the following operation to obtain the first and second converted out-of-gamut image data. 10. The method according to claim 8, wherein the first and second converted color gamut image data are compressed in the same compression format as the color gamut image data. S1 '= S1-Smax S2' = Smax- (S2min-S2) where S1: first out-of-color-gamut image data S2: second-out-color-gamut image data S1 ': first-conversion-out-color-gamut image data S2 ': Second converted color gamut image data Smax: Maximum value that color gamut image data can take S2min: Arbitrary value that second color gamut image data can take 12. The apparatus according to claim 1, wherein the out-of-color-gamut image data comprises other device image data corresponding to color reproduction characteristics of another device different from the device. The described image data configuration method. 13. An image data forming apparatus for forming device image data corresponding to the color reproduction characteristics of a device for reproducing color image data, wherein the device reproduces image data within a color reproduction range reproducible in the device. Means for attaching one or more out-of-color-gamut image data that is impossible, and data configuration means for configuring the device image data with the in-color-gamut image data and the out-of-color-gamut image data. Image data configuration device. 14. The device according to claim 1, wherein the data configuration unit configures the device image data such that the in-color gamut image data and the out-of-color gamut image data are stored in separate files. Claim 1
3. The image data configuration device according to 3. 15. The device according to claim 12, wherein the data configuration unit is configured to configure the device image data such that the in-color-gamut image data and the out-of-color-gamut image data are stored in the same file. 14. The image data construction device according to claim 13, wherein: 16. The device according to claim 16, wherein the data configuration unit configures the device image data such that a bit resolution of the image data outside the color gamut is larger than a bit resolution of the image data within the color gamut. The image data composition device according to any one of claims 13 to 15, wherein 17. The device according to claim 1, wherein the data configuration unit is configured to configure the device image data such that a bit resolution of the image data outside the color gamut is the same as a bit resolution of the image data within the color gamut. 16. The image data composition device according to claim 13, wherein the image data composition device comprises: 18. The image data according to claim 13, wherein said data composing means is means for composing said device image data by compressing said color gamut image data. Component device. 19. The image data according to claim 13, wherein said data composing means is means for composing said out-of-color-gamut image data to constitute said device image data. Component device. 20. The apparatus according to claim 18, wherein said data structuring means is means for structuring the device image data by compressing the out-of-color-gamut image data. 21. The device according to claim 20, wherein said data structuring means is means for structuring the device image data such that the compression format of the in-color gamut image data and the out-of-color gamut image data is different. Image data composition device. 22. First out-of-color-gamut image data in which the out-of-gamut image data has a data value equal to or less than the minimum value of the in-gamut image data, and data in which the out-of-gamut image data has a maximum value. When the image data is composed of the second out-of-gamut image data having a value, the data composing means combines the first and second out-of-gamut image data into one out-of-gamut image data having a predetermined bit resolution. 21. A synthesizing means for obtaining combined out-of-color-gamut image data by means of a combination, and a compressing means for arranging data values of the out-of-color-gamut image data in a frame-sequential manner and compressing the data in a lossless compression format. Or the image data composition device according to 21. 23. First out-of-color-gamut image data, wherein the out-of-gamut image data has a data value equal to or less than the minimum value of the in-gamut image data, and data equal to or more than the maximum value of the in-gamut image data. When the image data is composed of second out-of-gamut image data having a value, the data constructing means converts the first and second out-of-gamut image data by the following operation to perform first and second conversions. Conversion means for obtaining out-of-color-gamut image data; and compression means for compressing the first and second converted out-of-gamut image data in the same compression format as the in-color-gamut image data. Claim 20 or 2
2. The image data configuration device according to 1. S1 '= S1-Smax S2' = Smax- (S2min-S2) where S1: first out-of-color-gamut image data S2: second-out-color-gamut image data S1 ': first-conversion-out-color-gamut image data S2 ': Second converted color gamut image data Smax: Maximum value that color gamut image data can take S2min: Arbitrary value that second color gamut image data can take 24. The image processing apparatus according to claim 13, wherein the out-of-color-gamut image data includes other device image data corresponding to the color-reproduction characteristics of another device different from the device. An image data configuration device according to any one of the preceding claims. 25. Converted device image data corresponding to the color reproduction characteristics of another device different from the device so as to correspond to the color reproduction characteristics of the device to obtain converted image data. 12. An image data conversion method comprising: dividing data into the in-color gamut image data and the out-of-color gamut image data; and obtaining the device image data by the image data configuration method according to any one of claims 1 to 11. Method. 26. The device image data obtained by the image data forming method according to claim 1, wherein the device image data is a device image data corresponding to a color reproduction characteristic of another device different from the device. A method for converting image data, comprising: 27. Converted device image data corresponding to the color reproduction characteristics of another device different from the device so as to correspond to the color reproduction characteristics of the device to obtain converted image data. 13. An image data conversion method, comprising dividing data into the color gamut image data and the color gamut image data, and obtaining the device image data by the image data configuration method according to claim 12. 28. The apparatus according to claim 12, wherein the device image data obtained by the image data forming method is converted into another device image data corresponding to a color reproduction characteristic of another device different from the device. Image data conversion method. 29. Color order conversion means for converting another device image data corresponding to the color reproduction characteristics of another device different from the device so as to correspond to the color reproduction characteristics of the device to obtain converted image data. 24. A means for dividing the converted image data into the in-color gamut image data and the out-of-color gamut image data, and the image data configuration device according to any one of claims 13 to 23. Image data conversion device. 30. The image data forming apparatus according to claim 13, wherein the device image data obtained by the image data forming apparatus is converted into a color reproduction characteristic of another device different from the device. An image data conversion apparatus comprising: a color inverse conversion unit that converts the image data into another corresponding device image data. 31. Color order conversion means for converting another device image data corresponding to the color reproduction characteristics of another device different from the device so as to correspond to the color reproduction characteristics of the device to obtain converted image data. 25. An image data conversion apparatus, comprising: means for dividing the converted image data into the in-color gamut image data and the out-of-color gamut image data; and the image data configuration device according to claim 24. 32. An image data forming apparatus according to claim 24, wherein the device image data obtained by the image data forming apparatus is converted into another device image data corresponding to a color reproduction characteristic of another device different from the device. An image data conversion device, comprising: a color inverse conversion means for converting the image data into a color image. 33. The image data conversion device according to claim 29, wherein the device, and the device image data obtained by the image data configuration device correspond to color reproduction characteristics of another device different from the device. An image data conversion system, comprising: a color inverse conversion unit that converts the image data into another device image data to be converted; and the other device.