JP2002033901A - Image-inputting device and image-outputting device, and printed matter and recording medium and file- converting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To share a color image as a device, independent of colors by preventing color attribute information from being lost, even if color image is preserved in any file format. SOLUTION: This device is provided with an image-inputting means 1 for acquiring a digital image, a color attribute acquiring means 2 for acquiring color attribute information, to be referred to at conversion of the inputted digital image into a device-independent color, and a watermark-embedding means 3 for embedding the acquired color attribute information in the acquired digital image itself as an electronic watermark.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image input device, an image output device, and a technique for handling color attribute information.

[0002]

2. Description of the Related Art In recent years, devices handling color images have increased. For example, as an image input device, there are a color image scanner, a digital still camera, a video camera, etc., and as an image output device, a color printer, a CR,
T, a liquid crystal display, and the like, and further, as an image input / output device, there are a color digital copying machine, a scanner printer, a color facsimile, and the like. And it is inconvenient if these different devices cannot share a color image.

[0003] However, different devices have different color reproducibility. Even when the same device is used, the color reproducibility changes when the mode changes.

[0004] Therefore, attempts to share a color image with a plurality of users or devices often fail.

[0005]

Therefore, it is conceivable to use a file format (device-independent color) that does not depend on a device. However, some devices do not support such a file format, and when converted to a file format having no such area, the color attribute information is lost. That is,
Relying on the header part of the image file cannot solve the problem sufficiently.

Further, depending on the header part, the size of the color attribute information added to the header part may be larger than the image data size, which is not practical in network distribution.

[0007] Further, even if handled independently of the device, if the printed matter is printed, the color attribute information is lost.

On the other hand, JP-A-10-308870 discloses a technique for adding additional information to an image itself. That is, in this device, an image generated by the input device is provided with an encryption code or a graphic mark.
The additional information is embedded, and the image forming unit determines whether the image can be formed.

However, the purpose of this method is to prevent illegal copying of banknotes and the like, and what is added to the image is the history information obtained by processing the image. It cannot be converted to color.

Accordingly, it is a first object of the present invention to provide an image input apparatus capable of sharing a color image with device-independent colors without losing color attribute information no matter what file format is stored. .

A second object of the present invention is to provide an image output device capable of faithfully reproducing colors.

It is a third object of the present invention to provide an image output device, a printed matter, and a recording medium that can retain color attribute information even when printing.

It is a fourth object of the present invention to provide a file conversion apparatus in which color attribute information is not lost even if the file format is converted.

[0014]

According to the present invention, for the first object, image input means for acquiring a digital image and color attribute information referred to when the input digital image is converted into a device independent color. , And an watermark embedding unit for embedding the acquired color attribute information in the acquired digital image itself as a digital watermark.

Further, in the present invention, for the second object, a watermark extraction for extracting color attribute information embedded as a digital watermark from a digital image and referred to when converting the digital image into a device independent color. Means, a color system conversion means for converting the color system of the digital image using the acquired color attribute information, and an image display means for displaying the converted image to constitute an image output apparatus. .

Further, in the present invention, for the third purpose, an image output means for outputting an image to a print medium, and color attribute information of the image output means for a device independent color are embedded in a digital image as a digital watermark. And an watermark embedding unit for providing the embedded digital image to the image output unit to constitute an image output apparatus.

Similarly, the present invention provides a printed matter on which an image is printed by an image output unit, and in the image itself, color attribute information for a device-independent color of the image output unit is embedded as a digital watermark. Providing printed matter

According to the present invention, there is provided a recording medium for recording an image file in a computer-readable manner, wherein the image file has an image data portion, and the image itself is expressed by the image data portion. The present invention provides a recording medium in which color attribute information referred to when converting is converted into a device-independent color is embedded as an electronic watermark.

Further, in the present invention, for the fourth object, the first image file according to the first file format is converted into a second image file according to the second file format, and
Image data acquisition means for acquiring a digital image from an image file of the image data, color attribute acquisition means for acquiring color attribute information referred to when converting the acquired digital image into device-independent colors, and the acquired digital image itself. A watermark embedding unit that embeds the acquired color attribute information as a digital watermark, a format conversion unit that converts a digital image in which a digital watermark is embedded so as to conform to a second file format, And a file output unit for outputting the file as a second image file.

[0020]

Next, an embodiment of the present invention will be described. First, the relationship between device-independent colors and device-dependent colors will be described with reference to FIG. FIG. 1 is a diagram showing the relationship of color system conversion in the present invention.

As described in the section of the prior art, a device handling a color image has its own color reproducibility, and the colors handled by each device depend on device-dependent colors. Even if they have RGB values, they are actually separate from each other.

In order to share a color image of each device using device-independent colors, as shown in FIG. 1, (1) conversion from input device colors to device-independent colors in image input means, and (2) device Conversion from independent colors to print device colors and (3) conversion from device independent colors to monitor device colors are required. In this specification,
A monitor device (for example, a CRT or a liquid crystal display) and a print device (for example, a color printer)
Collectively referred to as "image output device".

At the time of conversion of these color systems, color attribute information determined from the characteristics of each device is required. In the present invention, the color attribute information is embedded separately as an electronic watermark in the image data itself, instead of being separated from the image data. That is, unless the digital watermark (color attribute information) is positively separated from the image data, the color attribute information is inherent in the image data itself.

Therefore, there is no area for storing the color attribute information, and the data holding method does not inherently support the color attribute information (memory allocation using a structure, class type, array, or the like, as well as a file format). , A file or a stream of memory blocks by such a memory allocation) is adopted, as long as the color image itself can be stored without omission, the color attribute information inherent in the color image can also be stored. , Can be held.

More specifically, the color attribute information (digital watermark) is not lost even if the data is converted into a format that does not have a storage area for the color attribute information. , Color attribute information (digital watermark)
Remain in a state that can be read later. Moreover, the color image itself may be compressed or uncompressed.

The color attribute information describes the characteristics of the color system constituting the image in the corresponding device, and is a parameter that can be converted into a device-independent color system.
Anything is fine.

For example, gamma characteristics of the image sensor, characteristics of the light source, characteristics of the ink, chromaticity, colorimetric value, gamma value, one-dimensional variable coefficient of the image input means, color table, matrix conversion coefficient, illumination information, device ID From the information, the information may be one type or a combination of two or more types.

When a digital camera or the like is used as the image input device, it is preferable to embed lighting conditions at the time of camera photographing. In this way, the illumination light can be converted later.

It is also preferable to embed device ID information. This is because color attribute information can be uniquely determined with small ID information.

The embedding of the digital watermark is performed, for example, by
A known technique as described in Japanese Patent Application Laid-Open No. H11-196262 may be used. By the way, when the digital watermark is embedded in the color image, the image quality of the color image is
Degrades even slightly. However, since a color image generally has high redundancy, even if a digital watermark is embedded, it is very difficult to visually recognize the image with human eyes, and practically, image quality degradation hardly causes a problem.

Next, Embodiment 1 will be described with reference to FIG.
Will be described. The image input unit 1 captures a subject or a document, such as a color image scanner, a digital still camera, a video camera, or the like, and generates image data.

This image data is based on device-dependent colors, and the color attribute information for device-independent colors differs depending on the device characteristics of the image input means 1. The color attribute information also differs depending on parameters at the time of shooting (for example, illumination time, exposure time, aperture, etc.). The color attribute acquisition unit 2 acquires color attribute information from these parameters.

Then, the watermark embedding unit 3 embeds the color attribute information output by the color attribute obtaining unit 2 into the color image itself output by the image input unit 1 as an electronic watermark. Then, the embedded image is recorded on the recording medium S
For example, as a file.

Next, an image output apparatus according to the second embodiment will be described with reference to FIG. First, the watermark extracting means 4
Attempts to extract a digital watermark indicating color attribute information from an embedded image (which may be read by an image scanner or read from a file).

When the extraction is successful, the watermark extracting means 4 outputs color attribute information to the color system conversion means 7 together with the color image. If the extraction has failed, the watermark extraction unit 4 outputs the color image and the default color attribute information to the color system conversion unit 7.

The color system conversion unit 7 converts the color image obtained from the watermark extraction unit 4 into a device independent color using the color attribute information input from the watermark extraction unit 4.

The color attribute obtaining means 6 obtains the color attribute information of the image display means 8 (output device) and passes it to the color system conversion means 7. Then, the color system conversion means 7
Based on the color attribute information obtained from the color attribute acquisition unit 6, the color system is converted from a device-independent color to a color dependent on the output device, and output to the image display unit 8. As a result, the image display means 8 performs display in a device-dependent color.

Next, an image output apparatus according to the third embodiment will be described with reference to FIG. This image output apparatus prints an image in which a digital watermark (indicating color attribute information) is embedded on a print medium (for example, paper).

The color attribute obtaining means 11 obtains color attribute information based on device characteristics of the image output means 10,
It passes to the watermark embedding means 9.

When the watermark embedding unit 9 receives the image data in the device-independent color, the watermark embedding unit 9 converts the color attribute information of the image output unit 10 (output device) based on the color attribute information obtained from the color attribute obtaining unit 11. Embed as an electronic watermark in image data. The embedding of the digital watermark may be performed by a known technique. For example, embedding is performed by a pixel replacement type.

Then, the watermark embedding unit 9 converts the image data of the device-independent color into a device-dependent color of the image output unit 10 by color system, and outputs the converted image data to the image output unit 10. The image output unit 10 performs printing in a device-dependent color based on the converted image data.

In this way, the image of the printed matter has a digital watermark indicating the color attribute information. That is, the printed matter itself can have color attribute information.

For this reason, if this printed matter is scanned later using the image input device of FIG. 2, the color attribute information can be used so as to obtain the illumination information at the time of photographing by the camera.

Next, a fourth embodiment will be described with reference to FIG.
Will be described. In this file conversion device, the color attribute acquisition unit 32
Are the same type of elements as the color attribute acquisition units 2, 6, and 11, and the watermark embedding unit 33 is the same type of element as the watermark embedding units 3 and 9, and therefore the description is omitted.

The file input means 30 inputs a file from a recording medium or the like. Image data acquisition means 31
Acquires image data from the image data part of the input file.

The format conversion means 34 converts the format from the first file format of the conversion source to the second file format of the conversion destination. The file output means 35
The format-converted file is output to a recording medium or the like as a second file.

The file conversion apparatus shown in FIG. 5 can convert between various file formats. In this example, the first files to be converted include a file 10 (file format A), a file 11 (file format B), and a file 12 (file format C). There are a file 20 (file format A), a file 21 (file format B), and a file 22 (file format C), and the source and destination files can be selected in any combination from these files.

Here, in the file format A, a header section is provided separately from the image data section, and this header section has an area for storing color attribute information. In the file format B, a header section is provided separately from the image data section, but this header section has no area for storing color attribute information. In the file format C, there is only an image data portion, there is no header portion itself, and there is no area for storing color attribute information.

Here, a case where the file 10 is converted into the file 22 will be described. At this time, according to the conventional technique, the converted file 22 has only the image data part, so that the color attribute information originally provided in the file 10 is lost in the file 22.

However, in this embodiment, the file 10
Since the color attribute information of the header part and / or the color attribute information obtained by the color attribute obtaining means 32 are embedded as digital watermarks in the image data itself read from the image data part by the watermark embedding means 33, This color attribute information is not lost in the file 22 later.

Next, a case where the file 11 is converted into the file 21 will be described. At this time, according to the conventional technique, the converted file 21 has a header part but no area for storing color attribute information. The information will be lost in file 21.

In the present embodiment, however, the color attribute information acquired by the color attribute acquisition unit 32 is embedded as an electronic watermark in the image data itself in the image data portion of the file 22 by the watermark embedding unit 33. This color attribute information is not lost even in the file 21 of FIG.

[0053]

According to the present invention, the color attribute information is embedded in the digital image as a digital watermark, so that the color attribute information relating to the digital image can be stored without requiring a special storage area, and the color image can be stored in the digital image. The attribute information can be embedded in the digital image and stored without breaking the association. In addition, compatibility with many existing image file formats can be maintained. Further, the color attribute information can be used for color management of a digital image.

According to the fifth and sixth aspects, the color attribute information can be used for color management of a digital image, and is converted into a color system suitable for the characteristics of the output device, so that faithful color reproduction can be performed.

According to the seventh and eighth aspects, color attribute information can be held even in an analog medium called a printed matter. When scanning again, the color attribute information of the printed material can be used.

According to the ninth aspect, a file conversion apparatus is provided in which color attribute information is not lost even if the file format is converted.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship of color system conversion in the present invention.

FIG. 2 is a block diagram of the image input device according to the first embodiment;

FIG. 3 is a block diagram of an image output device according to the second embodiment;

FIG. 4 is a block diagram of an image output device according to the third embodiment;

FIG. 5 is a block diagram of a file conversion device according to the fourth embodiment.

[Description of Signs] 1 Color attribute acquisition means 2 Color attribute acquisition means 3, 9, 33 Watermark embedding means 4 Watermark extraction means 6, 11, 32 Color attribute acquisition means 7 Color system conversion means 8 Image display means 10 Image output means Reference Signs List 30 file input means 31 image data acquisition means 34 format conversion means 35 file output means S recording medium

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/60 H04N 1/40 D 1/46 1/46 Z (72) Inventor Takashi Inoue Kadoma City, Osaka 1006 Oaza Kadoma Matsushita Electric Industrial Co., Ltd.F-term (reference) TT06 TT09 5C079 KA15 LA01 LA02 LA40 LB02 MA01 MA17 NA03 PA01 PA02 PA03 PA05

Claims (9)

[Claims] An image input means for acquiring a digital image, a color attribute acquiring means for acquiring color attribute information referred to when converting the inputted digital image into a device independent color, and an acquired digital image itself And a watermark embedding unit for embedding the acquired color attribute information as a digital watermark. 2. The color attribute information includes image sensor characteristics, light source characteristics, ink characteristics, chromaticity, colorimetric value, gamma value, image input means one-dimensional variable coefficient, color table, matrix conversion coefficient, 2. The image input apparatus according to claim 1, wherein the image input apparatus includes one or a combination of two or more of the illumination information and the device ID information. 3. A watermark extracting means for extracting color attribute information embedded in a digital image as a digital watermark and referred to when converting the digital image into a device-independent color, and using the acquired color attribute information. An image output apparatus comprising: a color system conversion unit for converting a color system of the digital image; and an image display unit for displaying the converted image. 4. The color attribute information includes a characteristic of an image sensor, a characteristic of a light source, a characteristic of ink, a chromaticity, a colorimetric value, a gamma value, a one-dimensional variable coefficient of an image input means, a color table, a matrix conversion coefficient, 4. The image output device according to claim 3, wherein the image output device includes one or a combination of two or more of the illumination information and the device ID information. 5. An image output means for outputting an image to a print medium; and, in a digital image, color attribute information of the image output means for a device-independent color is embedded as an electronic watermark, and the embedded digital image is displayed in the image. An image output apparatus, comprising: a watermark embedding means for giving to an output means. 6. The color attribute information includes a characteristic of an image sensor, a characteristic of a light source, a characteristic of ink, a chromaticity, a colorimetric value, a gamma value, a one-dimensional variable coefficient of an image input means, a color table, a matrix conversion coefficient, 6. The image output apparatus according to claim 5, wherein one or a combination of two or more of the illumination information and the device ID information is included. 7. A printed matter on which an image is printed by an image output unit, wherein color attribute information for a device-independent color of the image output unit is embedded as an electronic watermark in the image itself. Printed matter. 8. A recording medium for recording an image file in a computer-readable manner, wherein the image file has an image data section, and
In the image itself represented by the image data section,
A recording medium characterized in that color attribute information referred to when converting this image into a device-independent color is embedded as an electronic watermark. 9. A file conversion apparatus for converting a first image file according to a first file format into a second image file according to a second file format, wherein a digital image is obtained from the first image file. Image attribute acquisition means for acquiring color attribute information, which is referred to when the acquired digital image is converted into device-independent color, and color attribute information for acquiring the color attribute information. Watermark embedding means for embedding as a digital watermark, format conversion means for converting a digital image in which a digital watermark is embedded so as to conform to a second file format, and outputting the converted digital image as a second image file A file conversion device comprising: a file output unit.