JP2003230019A - Display method, and display system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inform a user about the presence/absence of color tone variation in image data. <P>SOLUTION: A color conversion unit 12 minutely divides image data directly after color conversion (color correction) by a color conversion processing section 20 into a plurality of divided areas, and an electronic watermark embedding section 22 embeds in advance electronic watermark information indicative of the color tone characteristics of the image data in the divided areas to the image data by each divided area. When an image output apparatus 16 prints the image data, a color tone variation detection section 24 of an output controller 18 before the image output apparatus 16 searches the electronic watermark from image data (page data) being an output object, compares the color tone characteristic value of the searched electronic watermark with the actual color tone characteristic value of the image data in each area of the searched electronic watermark to discriminate the presence/absence of the color tone variation, and a display section 30 displays the image data (page data) being the output object while distinguishing the areas discriminated to have no color tone variation from other areas. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display method and a display system, and more particularly to a display method and a display system for displaying a detection result of color tone modification of image data.

[0002]

2. Description of the Related Art With the spread of computers (PC) and the Internet in recent years, digitization of images has been advanced. Digital image data (hereinafter referred to as image data) is subjected to image processing such as photo retouching, resolution conversion, and cropping on a computer using image processing software, and then output from an output device such as a display or printer. It can also be distributed on the Internet. Also, by using software for editing processing on a computer, an image based on image data is arranged in one page together with text data and images of other image data as necessary to generate page data showing an image of the entire page. It is also possible to perform edit processing to generate.

By the way, when an image based on image data is output from an output device such as a display or a printer, the color expression is different depending on the input device or the output device such as a scanner or digital camera. It depends on the output device. Therefore, when a computer handles image data, it is often the case that the image data is first subjected to color correction (color conversion) in accordance with device characteristics so that a desired color is obtained at the time of output. After that, scratches and dust on the image data are removed by photo retouching, resolution conversion and clipping are performed to process to a desired image, and page editing is performed.

[0004]

However, conventionally, there is no technique for detecting / notifying the presence or absence of color tone modification of image data after color correction, and printing is performed despite the color tone modification. Sometimes the final output image was different from the expected color. That is, even if the image data is color-corrected in advance so that the color at the time of output becomes a predetermined color by using the color correction software, some processing is performed by other software in the step after the color correction. At the time of execution, unintended color conversion was performed due to processing peculiar to the software used and operation mistakes, and the color of the final output image changed.

It is possible to add confirmation data such as a checksum as header information to the image data at the time of color correction in order to detect the color tone modification. However, in this confirmation data, in the process after the color correction, When processing other than color conversion is performed on the image data after color correction, it is not possible to selectively confirm only the presence or absence of unintended color conversion.
Further, the confirmation data added by the header information may be lost in a subsequent process, such as the header information being deleted by the format conversion of the image data.

In particular, when the editing process is performed, image data imaged in a state where image data after color correction and other component data such as text data are mixed is obtained as page data, and the image after color correction is obtained. Since the data becomes a part of the page data, it is required for the page data to be notified so that the portion whose color tone has been changed and the portion whose color tone has not been changed can be distinguished.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a display method and a display system capable of notifying the presence or absence of color tone modification of image data.

[0008]

In order to achieve the above object, the invention as set forth in claim 1 is a display method for displaying a detection result of color tone modification of image data, wherein the predetermined area A region in which a digital watermark is embedded is searched for from image data including digital watermarked image data in which color tone characteristic value information indicating a color tone characteristic value is previously embedded by a digital watermark, and Based on the color tone characteristic value indicated by the color tone characteristic value information of the digital watermark embedded in the area and the actual color tone characteristic value in the area where the digital watermark of the image data including the digital watermark added image data is searched. , The presence or absence of color tone modification in the region searched for the digital watermark is determined, and at least the region determined to have no color tone modification and the other regions are distinguished, Displaying at least a portion of the non-image data, and characterized in that.

According to a second aspect of the present invention, there is provided a display system for displaying a detection result of color tone modification of image data, wherein color tone characteristic value information indicating a color tone characteristic value of each predetermined region is previously digitally watermarked. A region in which a digital watermark is embedded is searched for from image data including embedded digital watermarked image data, and for each region for which a digital watermark is searched, color tone characteristic value information of the digital watermark embedded in the region is searched. Whether or not the color tone of the area searched for the digital watermark is changed based on the color tone characteristic value shown and the actual color tone characteristic value in the area searched for the digital watermark of the image data including the digital watermarked image data. Based on the determination result by the determination means, at least the area determined to have no color tone modification and the other area are distinguished, and the electronic transparency is determined. It is characterized by comprising display means for displaying at least a portion of the image data including the image data attached, a.

According to the first and second aspects of the invention, in the digital watermarked image data, the color tone characteristic value information indicating the color tone characteristic value of each predetermined region is embedded in advance by the digital watermark. A region in which a digital watermark is embedded is searched for from image data including this digital watermarked image data. The image data including the image data with the digital watermark may be a single image data with the digital watermark, or, for example, the image data with the digital watermark may be combined with other image data and text data by an editing process.
Image data in which digital watermarked image data is a part of the whole may be used, such as page data showing an image of the entire page arranged and generated in a page.

When the digital watermark is searched, for each area where the digital watermark is searched, the color tone characteristic value indicated by the color tone characteristic value information of the digital watermark embedded in the area and the actual image in the area. Based on the color tone characteristic value of the data, the presence or absence of color tone modification is determined, for example, if the difference between the two is greater than or equal to a predetermined value, it is determined that the color tone has been modified. As a result, the presence or absence of color tone modification is determined for each portion of the image data including the digital watermarked image data corresponding to the digital watermarked image data for each digital watermark embedded area.
For example, when color conversion is performed on the digital watermarked image data after the digital watermark is embedded, the area corresponding to the digital watermarked image data in the image data including the digital watermarked image data is determined to have color tone conversion. ,
The color change can be detected.

As a result of the color tone modification detection, at least the area determined to have no color tone modification and the other areas (the color tone modified area and the area where the presence or absence of the color tone modification is unknown) are displayed separately. The user can judge the validity of the final output image by checking the display result.

When image processing or editing processing is performed on the digital watermarked image data, the size of the area in which the digital watermark is embedded is changed, or the size of the digital watermarked image data is changed depending on the arrangement position. Since the position of the area in which the digital watermark is embedded also changes, it is conceivable that the size and position of the area in which the digital watermark is embedded differ for each image data including the image data with digital watermark. Therefore, as described in claim 3, the determining unit changes the area size and the offset position of the search target area in the image data including the image data with the electronic watermark to determine the area in which the electronic watermark is embedded. You should search.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an example of an embodiment according to the present invention will be described in detail with reference to the drawings.

[Structure] FIG. 1 shows an image processing system to which the present invention is applied. As shown in FIG. 1, the image processing system 10 includes a color conversion device 12 for performing color conversion on input raster-format digital image data (hereinafter, abbreviated as “image data”), and a color conversion device 12 after the color conversion. Image processing device 14 for performing image processing on the image data, an editing processing device 15 for performing page editing by using the image data after the image processing, and an image on a sheet or the like based on the page data. The output control device 18 controls the operation of the image output device 16 for printing.

The color conversion device 12 and the image processing device 1
4, the edit processing device 15, and the output control device 18 may be physically independent devices, or one device may be a color conversion device 12, an image processing device 14, an edit processing device 15, and an output control device. Any two or more of the 18 functions may be performed. For example, one computer may be provided with a color conversion device 12, an image processing device 14, and an editing processing device 1.
5, and software for realizing each function of the output control device 18 is installed, and the installed software is appropriately selected and started in the computer, so that the color conversion device can be operated by one computer. 12, image processing device 14, and output control device 18
It can carry four functions. Further, the function of the output control device 18 may be provided in the image output device 16.

The color conversion device 12 includes a color conversion processing unit 20 for performing color conversion processing on image data, and a digital watermark embedding unit 22 for embedding a digital watermark in the image data. Image data acquired by, for example, a scanner or a digital camera, or image data received from another device via a network is input to the color conversion device 12, and the color conversion processing unit 20 inputs the input data. The converted image data is subjected to color conversion (color correction) processing so that an output of a predetermined color is obtained when output from the image output device 16.

More specifically, the color conversion processing unit 20 has a memory (not shown) in which profile information indicating color expression characteristics of each device such as an input device such as a scanner or a digital camera and an output device such as a printer is stored in advance.
The input image data is converted into a color system corresponding to the image output device 16 which is an output device, using the profile information of the corresponding input / output device. Specifically, in this embodiment, RGB is used as the input data.
Image data of a color system is input, and color conversion is generally performed into a YMCK color system which is a color system that can be processed by a printer. Note that the color conversion processing unit 20 performs color conversion to a device-independent color system (for example, L ^* a ^* b ^* color system), and is in a stage subsequent to the color conversion device 12 and at the image output device 16.
A unit for converting into a color system according to the output device may be further provided in front of.

Further, in the color conversion using the profile information, in consideration of the characteristics of the input device, the original color (if the color is acquired by the scanner, the color on the read original, or the color acquired by the digital camera) is used. For example, the color of the subject) can be corrected at the same time.

Further, in the case of a digital camera, information indicating photographing conditions such as whether or not a shutter is used may be added, and the color conversion processing section 20 uses this information to adjust the brightness of the image data. You may make it process.

The digital watermark embedding section 22 divides the image data after color conversion by the color conversion processing section 20 into areas (spaces) of a predetermined size, and for each of the divided areas,
A histogram of image data in the divided area is obtained as a color tone characteristic value indicating a color feature, and is used as a reference for determining whether or not there is a color alteration in a color tone alteration detection unit 24, which will be described later, for each obtained tone characteristic value. Therefore, the error tolerance is calculated.

Further, the digital watermark embedding unit 22 includes, in the image data of each divided region, information indicating the tone characteristic value (tone characteristic value information) obtained for the divided region and information indicating the error allowable value (error allowable value). Information) is embedded with a digital watermark. The image data in which the electronic watermark is embedded by the electronic watermark embedding unit 22 is output from the color conversion device 12 to the image processing device 14 in the subsequent stage as “image data with electronic watermark” of the present invention.

Besides the histogram, the maximum value, the minimum value, the average value, the variance, the covariance, and the mode value of the image data in the divided area can be used as the color tone characteristic value. Further, at least two or more of the histogram, the maximum value, the minimum value, the average value, the variance, the covariance, and the mode value may be combined and used as the color tone characteristic value. However, in the case of performing high-speed processing in a system having a low processing capacity, it is particularly preferable to adopt the average value among the above.

Regarding the allowable error value, a preset value is stored in an internal memory (not shown) of the digital watermark embedding unit 22, and this set value is used when embedding with a digital watermark. May be. Further, without embedding with a digital watermark, an error allowable value is set by the operation input unit 32, which will be described later, and is input to the color tone modification detection unit 24, or a preset value is stored in the internal memory of the color tone modification detection unit 24. You can leave it.

The method of embedding a digital watermark is not particularly limited in the present invention, and conventionally known techniques such as a pixel space utilization type, a quantization error utilization type and a frequency domain utilization type can be used. . However, in order to prevent the information embedded when the image data is processed in the image processing device 14 from being lost, depending on the specific processing process performed by the image processing device 14 and the type of the processing function of the image processing device 14. , It is necessary to select an appropriate embedding method.

The pixel space utilization type is a method in which a plane of, for example, 3 × 3 pixels near a target pixel is taken out and watermark information is embedded in the surrounding bits. The quantization error utilization type pays attention to the quantization error generated in the process of compressing the image data, and sets 0 of the bit sequence of the watermark information (the color tone characteristic value information and the error allowable value information in this embodiment) to be embedded. , 1 to control the quantized output to an even number and an odd number to embed the watermark information in the image data as an apparent quantization error. The frequency domain utilization type converts image data into frequency components as typified by Fourier transform, spread spectrum, discrete cosine transform (DCT), etc., and a specific frequency component that has little influence on image quality, for example, visually. This is a method of embedding watermark information in insensitive high frequency components. Further, as a human visual characteristic, color difference and saturation information generally have lower gradation discrimination ability than luminance information, and a region that can be recorded so that a human cannot visually recognize the difference between luminance and color difference or saturation information. Exists. Therefore, the watermark information can be embedded in this area.

Besides, a method of embedding watermark information in a bit plane having a poor S / N as an image by making noise redundantly embedded, a method of embedding in the redundancy of information change in a certain pixel block, and a bond for data compression. There is a method of embedding in a quantization error when the data information amount is degenerated by the encoding.

The image processing device 14 performs image processing on the image data output from the color conversion device 12 as needed so as to obtain a desired image / image quality. In the embodiment, as an example, the photo retouching process is performed to remove the influence of dust and scratches when the image data is acquired by the scanner or the digital camera. The image processing performed by the image processing device 14 includes resolution conversion,
Examples include cutouts. Such an image processing device 1
4 can be realized by, for example, activating general software for image processing on a computer.
The image data processed by the image processing device 14 is input to the edit processing device 15 in the subsequent stage.

The edit processing device 15 arranges the image data input from the image processing device 14 in one page, and if necessary, text data and other image data (either raster format or vector format) are also included in the page. Place it inside
Raster format image data (hereinafter referred to as "image data including image data including digital watermarked image") of the present invention, which determines the layout within one page, creates an image based on the determined layout, , "Page data"). Such an edit processing device 15 can be realized by, for example, activating general software for edit processing on a computer. The page data generated by the edit processing device 15 is input to the output control device 18 in the subsequent stage.

The output control device 18 serves as a determination means, and the image processing device 14 for the image data after the color conversion (color correction) by the color conversion processing unit 20 included in the page data.
Also, a color tone modification detection unit 24 for detecting the presence or absence of color tone modification in the editing processing device 15, a user interface unit 26, and a driver unit 28 for operating the image output device 16 based on page data.

The color tone modification detection unit 24 determines whether or not other color conversion (color tone modification) has been performed by the image processing apparatus 14 or the editing processing apparatus 15 after the page data is subjected to color conversion (color correction) by the color conversion processing unit 20. To detect. Although not shown, the color tone modification detection unit 24 has an internal memory for storing various information at the time of this detection.

Further, the color tone alteration detection unit 24 sends the input page data to the driver unit 28, and the driver unit 2
At 8, the control signal is sent to the image output device 16 based on the image data. As a result, the image output device 16 outputs an image based on the image data.

The user interface unit 26 serves as a display means, such as a display unit 30 for displaying the detection result of the color tone modification by the color tone modification detection unit 24, and an image by the image output device 16 when operated by the user. An operation input unit 32 such as a keyboard and operation buttons for inputting information indicating whether output is possible is provided. In addition,
The display unit 30 and the color tone alteration detection unit 24 constitute the display system of the present invention.

[Operation] Next, the operation of the present embodiment will be described.

In the image processing system 10, the image data to be processed is input to the color conversion device 12. Hereinafter, the processing executed by the color conversion device 12 will be described in detail with reference to FIG. It should be noted that FIG. 2 shows a processing routine that is started by the color detection unit when image data is input.

As shown in FIG. 2, the color conversion device 1
In step 2, when image data is input, first, step 10
At 0, the color conversion processing unit 20 uses the profile information of the device to perform color conversion from the RGB color system to the YMCK color system. At this time, color conversion is performed by adding a correction according to the input device so as to approximate the original color.

Next, in step 102, the digital watermark embedding unit 22 divides the color-converted image data into areas of a predetermined size, and for each of the divided areas, the image data in the divided area is used as the tone characteristic value of the divided area. And the allowable error value according to the histogram. Then, in the next step 104, the information of the histogram as the color tone characteristic value information of each divided area is embedded in the image data of each divided area together with the error allowable value information by a digital watermark.

Here, the size of dividing the image data is not particularly limited as long as it is sufficient to embed the information to be embedded, that is, the tone characteristic value information and the error tolerance value information with a digital watermark. Then, as an example, as shown in FIG.
The image data is divided with an area of 000 pixels as one unit. In FIG. 3, the size of the entire image data is 1
It shows the case of 120 × 820 pixels, and 100 ×
When area division is performed in units of 100 pixels, an extra portion appears as shown by the diagonal lines in the figure. For this extra part,
It is necessary to handle in accordance with a predetermined rule. For example, if this remaining portion is of a size sufficient to embed the tone characteristic value information and the error tolerance value information as a digital watermark, the digital watermark will be processed like other divided areas. Can be embedded, and if the size is less than the sufficient size, embedding a digital watermark is not performed. Further, as can be seen from FIG. 3, this residual portion corresponds to the peripheral portion of the image, and if the peripheral portion is less important, the digital watermark may not be embedded in the residual portion.

Further, in the present embodiment, as an example, as shown in FIG. 4, pixel values of CMYK color components of 0 to 70, 71 to 18 as color tone characteristic values in each divided area are obtained.
A histogram in which the number of pixels having a pixel value in each section is counted by dividing into three sections of 0, 181, and 255 is adopted. It should be noted that the reason why the number of sections in the histogram is three is for the sake of simplification of description. In actuality, in order to accurately express the characteristics of the color tone, the number of sections in the histogram should be at least 10 or more. Is preferred.

The allowable error value may be any value that corresponds to the amount of change in the color tone characteristic value that can occur in normal processing for removing scratches and dust in the image processing apparatus 14,
In the present embodiment, as an example, the increase / decrease allowable range of the number of pixels in each section in the obtained histogram is adopted.
Specifically, if ± 5% is set as the increase / decrease allowable range, for the area number 1 in FIG.
The error allowable value is 500 pixels for each of 0 pixel, M, Y, and K colors. In this case, the allowable error range may be changed depending on the section, for example, ± 7% for a visually insensitive section and ± 3% for a visually sensitive section.

When the digital watermark is embedded in the color-converted image data in this way, the process of the color conversion device 12 in FIG. 2 is completed, and the image data after color conversion (color correction) by the color conversion device 12 is processed by the image processing device. 14 is input. The image data, which has been color-converted by the color conversion device 12 and in which the digital watermark is embedded, is subjected to image processing (photoretouching) as necessary by the image processing device 14, and the influence of scratches and dust is removed from the image data. High-quality image data is output. Note that there is a possibility that unintended color conversion may be accidentally applied to the image data during this image processing.

Image data (hereinafter referred to as "color-corrected image data") that has been color-converted (color-corrected) by the color conversion device 12 and subjected to image processing by the image processing device 14 as necessary is It is input to the edit processing device 15. In the edit processing device 15, this color-corrected image data is arranged in one page, and if necessary, text data and other image data (which may be in raster format or vector format) are also arranged in the page and 1 Determines the layout on the page. Then, based on the determined layout, page data that is image data in a raster format showing an image of the entire page is generated. Specifically, FIG. 5 shows an example of page data generated by performing the editing process by the editing processing device 15 using the image data (color-corrected image data) shown in FIG. The page data of FIG. 5 shows a state in which the color-corrected image data of FIG. 3 is pasted in a page together with text data and other image data. As can be seen, the color-corrected image data is It becomes part of the page data.

The page data generated by the edit processing device 15 is input to the output control device 18 in the subsequent stage. In the output control device 18, this page data is first input to the color tone modification detection unit 24, and in the color tone modification detection unit 24, the digital watermark embedded in the color-corrected image data in the page data by the digital watermark embedding unit 22. Based on the information, the presence or absence of another color conversion (color tone modification) performed by the image processing device 14 or the editing processing device 15 after color conversion (color correction) by the color conversion processing unit 20 is detected.

Hereinafter, with reference to FIG. 6, the processing executed by the color tone modification detecting section 24 will be described in detail. In Figure 6,
A processing routine that is started by the color tone modification detection unit when image data is input is shown.

As shown in FIG. 6, in the color tone alteration detecting section 24, when page data is input, first in step 200, from the input page data,
The electronic watermark embedded by the electronic watermark embedding unit 22 in the color-corrected image data included in the page data is searched. At this time, the position of the color-corrected image data differs depending on the page data, and the image processing device 14
In some cases, the image size may be changed and attached to the page data due to the resolution conversion of the image data during the image processing in the image processing or the editing processing in the editing processing device 15, and the color correction in the page data has been completed. Since the position and size of the image data are unknown, the digital watermark is searched while changing the offset position and the size of the area for searching the digital watermark in the page data. Here, if at least one color-corrected image data is included in the page data, the electronic watermark embedded in the first divided area in the first color-corrected image data included in the page data Is detected.

When the digital watermark is detected,
The process proceeds from the next step 202 to step 204, and when the digital watermark is not detected, the process proceeds from step 2020 to step 220 described later.

At step 204, the offset position and the area size of the area in the page data where the digital watermark is detected, here the first divided area in the first color-corrected image data, are stored in an internal memory (not shown). ), The process proceeds to step 206.

In step 206, the retrieved digital watermark information, that is, the color tone characteristic value information and the error tolerance value information are read. Then, in the next step 208, the data in the area in which the electronic watermark of the page data was embedded,
That is, a color tone characteristic value, specifically, a histogram is obtained from the actual image data of the divided area of the color-corrected image data corresponding to the digital watermark. At this time, since the image size may have been changed since the digital watermark was embedded, the histogram obtained according to the size of the original divided area is normalized. For example, the original divided area size is 10
If the area size (area size stored in step 204) in which the first digital watermark is searched for is 0 × 100 pixels, but is 50 × 50 pixels, the number of pixels in each section of the obtained histogram (Frequency) is quadrupled.

Then, in the next step 210, the color tone characteristic value obtained from the actual image data in step 208 is based on the error tolerance value information of the digital watermark read in step 206, and the color tone of the digital watermark read in step 206 is obtained. It is determined whether or not it matches the characteristic value information. Specifically, if the difference between the color tone characteristic value obtained from the actual image data and the value indicated by the read color tone characteristic value information is within the range of the value indicated by the error tolerance value information, the values match and the value indicated by the error tolerance value information If it is out of the range, it is determined that they do not match. Specifically, in the present embodiment, if even one of the three sections of the YMCK color histogram is out of the range, it is determined that they do not match.

If it is determined that the color tone characteristic value obtained from the actual image data matches the color tone characteristic value information of the digital watermark, it is determined that the color tone of the divided area has not been changed (no color tone change). Then, the process proceeds from step 210 to step 212, and after the position and size in the page data of the divided area is stored, the process proceeds to step 214. On the other hand, if it is determined that they do not match, it is determined that the color tone of the divided area has been changed (there is a color tone change), and the process directly moves from step 210 to step 214.

In step 214, a digital watermark is searched from the area of the same size adjacent to the last divided area in the page data, which has been judged as to the presence / absence of color tone modification. For the area to be searched for this digital watermark, see step 2 above.
By referring to the offset position and the area size stored in 04, it is possible to easily determine the area of the same size adjacent to the divided area in which the presence / absence of color tone change is finally determined.

Then, when a digital watermark is detected from an area of the same size adjacent to the divided area for which the presence / absence of color tone modification is determined immediately before, the processing returns to the next step 216 to step 206 and the same processing is repeated. . As a result, the digital watermarks embedded in the second divided area, the third divided area, ... In the first color-corrected image data are sequentially detected, and it is determined whether or not there is a color tone change for each divided area. The positions and sizes of the divided areas that have been subjected to color tone modification are stored.

On the other hand, when the digital watermark is not detected, it is determined that the presence or absence of color tone modification has been completed for all the divided areas in the first color-corrected image data, and the flow advances from step 216 to step 218. In step 218, it is determined whether or not the processing relating to the search of the digital watermark and the presence / absence determination of the color tone modification has been completed for all the areas of the page data. .

On the other hand, if there is a remaining area, it is determined that another color-corrected image data may remain in the page data, and the process returns from step 218 to step 200, and the offset position of the search area and the area. Search digital watermarks while changing the size. At this time, the offset position and the area size of the search area are changed starting from the position adjacent to the divided area in the page data where the presence or absence of the color tone change is determined last.

As a result, if the page data includes a plurality of color-corrected image data and there is still color-corrected image data for which the presence / absence of color tone change has not been determined, the next color-corrected image data is obtained. The digital watermark embedded in the first divided area of the image data is detected, and similarly, the processing shifts from the next step 202 to step 204 and subsequent steps. That is, following the first color-corrected image data, the second color-corrected image data, the third color-corrected image data, ... Whether or not the color tone has been changed is determined for each divided area of the completed image data, and the position and size of the divided area in the page data that has not been color changed is stored.

After that, when all the color-corrected image data included in the page data are processed, the electronic watermark is not detected even if the offset position and the area size of the search area are changed. Therefore, steps 202 to 220 are executed. Move to.

In step 220, display data representing the detection result of the presence or absence of color tone modification from the page data is generated based on the position and size of the divided area in the stored page data where the color tone has not been modified, It is displayed on the display unit 30 of the user interface unit 26.

Specifically, FIG. 7 shows a display example of the detection result of the presence / absence of color tone change displayed on the display unit 30 when the presence / absence of color tone alteration is detected for the page data shown in FIG. Indicates. In FIG. 7, a real image using the actual data of the page data is displayed only in the area determined to have no color tone modification, and the other areas are so-called solid display filled with gray color. That is, the page data is displayed separately in the area where the color tone is not changed and the other areas. Note that other areas include an area determined to have a color tone modification (a color tone has been modified) and an area in which the presence or absence of a color tone modification is unknown because the digital watermark is not embedded. The unknown region includes the peripheral portion of the color-corrected image data other than the color-corrected image data.

The user judges the validity of the final output image from this display, operates the operation input section 32 of the user interface section 26, and inputs the information for instructing the image output from the image output apparatus. That is, if the area where there is a possibility of color tone modification is a part where the color tone is particularly acceptable and a proper final output image is obtained, enter the information for instructing image output, and if the color tone changes, there is a problem. If it is in the area where there is a possibility of color tone modification, it is considered that only an inappropriate final output image can be obtained, and the information for instructing to stop the image output is input.

In the color tone alteration detection section 24, the following step 2
In step 22, the process waits until the user inputs the information instructing whether to output the image, and when the information instructing the image output is input as the information instructing whether to output the image, from step 222. Steps 224, 2
26, the page data is sent to the driver unit 28, and the process ends. The driver unit 28 sends a control signal to the image output device 16 based on the page data. As a result, the image output device 16 outputs the paper on which the image (page) based on the page data is printed. At this time, it goes without saying that the information embedded in the color-corrected image data with a digital watermark has almost no effect on the image quality.

When the information for instructing to stop the image output is input as the information for instructing the image output, the process proceeds from step 222 to steps 224 and 228, and the transmission of the page data to the driver unit 28 is stopped. Ends the process.

As described above, in the present embodiment, the image data immediately after the color conversion (color correction) is performed on the image data subjected to the color conversion (color correction) by the color conversion processing unit 20 of the color conversion device 12. The data is subdivided into a plurality of divided areas, and the electronic watermark embedding unit 22 of the color conversion device 12 pre-embeds information indicating the color tone characteristic value of the image data in the divided areas by the electronic watermark for each divided area. When the image output device 16 prints, the image output device 1 is detected by the color tone modification detection unit 24 of the output control device 18 in front of the image output device 16.
6, the digital watermark is searched from the image data (page data) to be output, and the tone characteristic value of the searched digital watermark and the actual image data in the area are searched for each area where the digital watermark is searched. By comparing with the color tone characteristic value, the presence or absence of color tone modification after color conversion (color correction) by the color conversion processing unit 20 is determined. This allows
Image processing in the image processing device 14 (photo retouching)
When an unintended color conversion is performed during the editing process in the editing processing device 15 or the color tone characteristic value of the image data is changed by the color conversion, the color tone characteristic value is different from the tone characteristic value embedded in the digital watermark. Therefore, the color tone modification detector 24 can detect the presence or absence of color tone modification. At this time, the color tone modification detection unit 24 handles the modification of the image data by the image processing (photo retouching) other than the color conversion as normal, and can detect the modification of only the color tone.

Further, in the color tone alteration detection section 24, when retrieving a digital watermark from the image data (page data) to be output, the digital watermark is retrieved while changing the retrieval position (offset position) and the area size, Color converter 1
Since the first digital watermark of each image data subjected to color conversion (color correction) by the second color conversion processing unit 20 is detected,
Even if the image data subjected to the color conversion (color correction) by the color conversion processing unit 20 of the color conversion device 12 by the editing processing by the editing processing device 15 is made a part of the output target image data (page data). It is possible.

Further, by displaying the image data (page data) of the output target on the display unit 30 of the user interface unit 26 while distinguishing between the region determined to have no color tone modification and the other region, the output target image data is displayed to the user. It is possible to notify the detection result of the presence or absence of color tone modification in the image data,
This allows the user to judge the validity of the final output image. Regarding the distinctive display, in addition to this,
It is possible to distinguish and display in three areas, an area determined to have no color tone modification, an area determined to have color tone modification, and an area in which the presence or absence of color tone modification is unknown.

Since the information indicating the color tone characteristic value is embedded in the image data by a digital watermark, the information indicating the color tone characteristic value disappears by the photo retouching process in the image processing device 14 as compared with the case of writing the header information. Unlikely.
Further, even if image processing such as resolution conversion and clipping is performed in the image processing apparatus 14 in addition to the photo retouching processing, there is a possibility that the information indicating the embedded tone characteristic value may be lost by adopting the digital watermark. Can be lowered. In this case, in order to prevent the disappearance of the information indicating the color tone characteristic value embedded by the digital watermark, according to the specific processing performed by the image processing apparatus 14 and the type of the processing processing function of the image processing apparatus 14, It is preferable to select a method of embedding a digital watermark. If there is a divided area in which the digital watermark disappears, the area is treated in the same manner as the case where it is determined that the color tone of the area is changed.

[0066]

As described above, the present invention has an excellent effect that it is possible to notify the presence / absence of color tone modification of image data.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing processing executed by the color conversion device.

FIG. 3 is a conceptual diagram for explaining division of image data by a digital watermark embedding unit of the color conversion device.

FIG. 4 is an example of a color tone characteristic value (histogram) of image data for each divided area obtained by a digital watermark embedding unit of the color conversion apparatus.

5 is an example of page data (image data showing an image of one page) generated when the edit processing is performed by the edit processing apparatus using the image data of FIG. 3;

FIG. 6 is a flowchart showing processing executed by a color tone modification detection unit of the output control device.

7 is an example of a display of the detection result of the presence or absence of the color tone modification displayed on the display unit when the presence or absence of the color tone modification is detected in the page data of FIG. 5 by the color tone modification detection unit.

[Explanation of symbols]

10 Image processing system 12-color converter 14 Image processing device 15 Editing processor 16 Image output device 18 Output control device 20 color conversion processing unit 22 Digital watermark embedding unit 24 Color change detection unit 26 User interface section 28 Driver 30 Display 32 Operation input section

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Claims (3)

[Claims] 1. A display method for displaying a detection result of color tone modification of image data, wherein an image with a digital watermark in which color tone characteristic value information indicating a color tone characteristic value of the predetermined region is embedded in advance by a digital watermark. A region in which a digital watermark is embedded is searched from image data including data, and a tone characteristic value indicated by the color tone characteristic value information of the digital watermark embedded in the region is searched for each region in which the digital watermark is retrieved. Based on the actual color tone characteristic value in the region where the digital watermark is searched for in the image data including the image data with the digital watermark, it is determined whether there is a color tone change in the region where the digital watermark is searched, and at least the color tone is changed. A display method characterized by displaying at least a part of image data including digital watermarked image data by distinguishing an area determined to be absent and an area other than the area Law. 2. A display system for displaying a detection result of a color tone modification of image data, wherein an image with a digital watermark in which color tone characteristic value information indicating a color tone characteristic value of the predetermined region is embedded in advance by a digital watermark. A region in which a digital watermark is embedded is searched for from image data including data, and a tone characteristic value indicated by color tone characteristic value information of the digital watermark embedded in the region is searched for each region for which a digital watermark is retrieved, and Determination means for determining whether or not there is a color tone modification in the region searched for the digital watermark, based on the actual tone characteristic value in the region searched for the digital watermark in the image data including image data with digital watermark; Based on the determination result by the determination unit, at least the area determined to have no color tone modification and the other area are distinguished from each other, and include image data with a digital watermark. Display system and having a display means for displaying at least a portion of the image data. 3. The determination unit searches the area in which the digital watermark is embedded by changing the area size and offset position of the search target area in the image data including the image data with the digital watermark. The display system according to claim 2.