JPH0487461A - Digital picture processor - Google Patents

Abstract

PURPOSE:To process the picture quality of a desired part without a brightness change by comparing the brightness component of a processing object picture data with a reference value, multiplying a compared value with the color difference signal of a reference color when the brightness component is the compared value or below and processing the processing object picture data with the obtained product color difference signal. CONSTITUTION:Chrominance signals R, G, B stored in a frame memory 12 is fed to an arithmetic circuit 15 by a data controller 16, the luminance signal (y) of a portrait 2 and a prescribed comparison value X are compared, and in the case of, e.g. X>y, a ratio of luminance signals Y, y, i.e., y/Y is multiplied respectively with color difference signal R-Y, B-Y. Then chrominance signals Ra, Ga, Ba are obtained based on the luminance signal (y) of the portrait 2, and corrected color difference signals (R-Y)' and (B-Y)'. Thus, even in the case of reproduction after luminance color-difference separation, the picture corresponding to the processing object picture data, that is the brightness component of the picture is not largely fluctuated. Thus, the picture quality is processed without decreasing the brightness of the portrait 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a digital image suitable for converting digitized image data and processing a part of the image into a desired color for reproduction. Regarding processing devices, the present invention can be widely applied to various video devices such as color printers, color copying machines, color facsimiles, and color displays.

[Conventional technology]

2. Description of the Related Art When reproducing image data obtained by photographing or image data generated by a computer, it may be desired to perform image quality processing such as changing the color of a part of the image. This-
To explain an example with reference to FIG. 3, when recording and reproducing image data obtained by photographing a person B with a blue sky 1 in the background, the color of the person 2 is changed to a color different from the original color, for example, the blue sky. There may be times when you want to create a picture, such as changing the color component of 1 to a color that uses it and reproducing it.

If this kind of picture creation can be done arbitrarily, it will be possible to diversify and improve efficiency when doing graphic design, etc., and it will be possible to become a specialist in video equipment that goes beyond the skill level of simply enjoying unusual picture making. It becomes possible to make the target multi-functional.

ノ/ Therefore, the present inventor conducted various technical studies to develop a digital image processing device that can perform the above-mentioned picture creation, in other words, image quality processing, but during the study, the following occurred. The issues that need to be solved have become clear.

[Problem to be solved by the invention]

That is, the luminance signal of blue sky 1 is Y, and the color signals are R (red) and G(
The luminance signal of the person 2 is y, and the color signals are r, g, and b. It has been found that when attempting to change the color of, for example, the chest of person 2 using color signal B, for example, the luminance signal y of person 2 becomes larger than its original value.

It has also been found that when the luminance signals Y and y have a relationship of Y>y, changes in the luminance signal y appear particularly remarkable.

Therefore, the inventor of the present invention has considered combining colors that are desired to be changed without changing the luminance information of the image portion to be processed, that is, the person 2 according to FIG. 3, and has accomplished the present invention.

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital image processing device configured to combine color information that suppresses the phenomenon of changes in brightness information of an image portion to be processed, and to perform desired image quality processing.

[Means to solve the problem]

The present invention provides - in a digital image processing device configured to record or reproduce digitized image data forming an image, a processing object that is a part of the image data and that is to be processed into a desired color; The first luminance component value in the image data is compared with the second luminance component value in arbitrary reference color data to be replaced with the processing target image data, and when this comparison value is a predetermined value or more, the corresponding A new color difference signal is created from the color difference signals of reference colors based on the comparison value, and the image data to be processed is replaced with the new color difference signal.

[For production]

According to the digital image processing device having the above configuration, when the difference between the luminance component of the image data to be processed and the luminance component of the reference color data to be replaced by the image data to be processed is large,
Processing of the image data to be processed is performed using a color difference signal obtained by correcting a color difference signal of the reference color data using a comparison value between the luminance component and the luminance component of the reference color data.

Therefore, the corrected color difference signal corresponds to the luminance component of the image data to be processed, and if the image is re-transferred based on this corrected color difference signal, the luminance fluctuation will be suppressed despite the image quality processing. It will be reduced. Therefore, it is possible to improve the functionality and make the digital image processing device multifunctional.

〔Example〕

Hereinafter, an embodiment of a digital image processing apparatus to which the present invention is applied will be described with reference to FIGS. 1 and 2.

Incidentally, FIG. 1 is a flowchart showing image data processing, and FIG. 2 is a circuit block diagram, and FIG. 3 will be referred to as appropriate in explaining this embodiment.

The generation form of the image data referred to in the present invention is not particularly limited, and may be, for example, image data obtained by photographing a blue sky 1 or a person 2 shown in FIG. 3 with a digital electronic still camera. In this case, the image data to be processed in the present invention is the person 2.
The sample image data corresponds to the image data of the blue sky l.

As an embodiment of the present invention, a case where image quality processing is applied to a person 2 will be described. In this case, as shown in step S1 in FIG.
, C;, luminance signal Y (1 variable component), color difference signal R- from B
Find Y, BY.

Next, as shown in step S2, a luminance signal y (luminance component) and color difference signals ry, b-y are obtained from the color signals R, G, and B of the person 2, which are the image data to be processed.

In step S3, the brightness signal y of the person 2 is compared with a predetermined comparison value X. For example, if x>y, in other words, if the brightness signal y of the person 2 is at a low level, In order to reduce the change in the luminance signal y, a correction as shown in step S4 is performed. That is, for the color difference signal R-Y, the calculation (R-Y)·y/Y is performed to obtain a corrected color difference signal (R-Y)'. Further, for the color difference signal B-Y, the calculation of (B-Y).y/Y is also performed to obtain a corrected color difference signal (B-Y)'.

In this way, in step S4, each color difference signal R-Y, B-
Y is multiplied by the luminance signal Y and the comparison value of y, that is, y/Y. As described above, when x>y, the relationship Y)y holds for the luminance signal. Corrected color difference signal (RY)'
(BY)' changes according to the luminance signal y, and corresponds to the component of the luminance signal y at least more than the original color difference signals RY and BY.

Next, as shown in step S5, the luminance signal y of the person 2
, color signals Ra, Ga, and Ba are obtained based on the corrected color difference signal (RY)'(By)'. Image reproduction is then performed based on the color signals Ra, Ga, and Ba.

Since the color signals Ra, Ga, and Ba have already been corrected according to the luminance component y of the image data to be processed,
Even if the luminance/color difference separation is performed and the image is reproduced, the luminance component of the image corresponding to the image data to be processed, that is, the person 2 in this embodiment, does not change significantly. Therefore, image quality processing can be performed without reducing the brightness of the person 2.

On the other hand, if it is determined in step S3 that the luminance signal y is not less than or equal to the comparison value X, the calculation in step S4 is not performed and the process moves to step s5. In this case, color signals Ra, G are generated based on the luminance signal y and color difference signals RY, BY.
Find a and Ba. However, since the luminance signal y is not at a low level, there is no significant luminance variation even if the color signals Ra, Ga, and Ba are separated into luminance and color difference and image reproduction is performed.

In other words, by performing the above calculation, if the luminance component of the person 2, in other words, the luminance signal y, is at a low level, the image quality will not be processed directly by the color difference signal of the blue sky], so the fluctuation of the luminance signal y will be reduced. reduced.

Next, a configuration of a digital image processing apparatus that enables the image quality processing described above will be explained with reference to FIG.

The selector 11 switches input and output, and is supplied with color signals R, G, and B as input data.

The frame memory 12 stores color signals R, , , which are input data.
G, B storage and the corrected color signals Ra, Ga,
It is for storing Ba etc. in a readable manner.

The control device 13 centrally performs switching control of data input and data output, control of the address controller 14, control of the arithmetic circuit 15, and the like. The arithmetic circuit 15 and data controller 16 perform arithmetic control for the correction described in steps S1 to S5.

Next, the circuit operation at the time of data input will be sequentially explained. In this case, the control device 13 switches the selector 11 to data input. The color signals R, G, and B are stored in the frame memory 12, and their addresses are controlled by an address controller 14.

Then, storage of image data for ] frames is completed, and if image quality processing is to be performed, the controller W13 switches to the correction operation shown in the flowchart.

That is, the color signals R stored in the frame memory 12,
G and B are supplied to the arithmetic circuit 15 by the data controller 16, and the correction operations shown in steps 31 to s5 are performed.

The corrected image data is stored in the frame memo 2 again via the data controller 16. At this time, if the input data is in a field array, it will be stored in a state in which the above-mentioned correction and conversion to a frame array have been performed.

Next, the reproduction operation will be described. The control device 13 drives the selector 11, reads out the color signal stored in the frame memo 2, and supplies it to the D/A converter 17. At this time, regarding the image data for reproducing person 2,
The corrected color signals Ra, Ga, and Ba are read out. Therefore, the D/A converter 17 is sequentially supplied with uncorrected image data for reproducing the blue sky 1 and the like and corrected color signals for reproducing the person 2.

The image data is converted into an analog signal by the D/A converter 17, and reproduced visually as one frame image by the display device 18.

A luminance/color difference separation circuit (not shown) is provided after the D/A converter 17, and the luminance signal and color difference signal of the uncorrected blue sky 1 and the corrected person 2 are sent to the display device 1B. supply In the reproduced image, person 2
The image quality has been processed using the blue sky 1 color difference signal.

In this way, the digital image processing apparatus shown in this embodiment is capable of: - Even if the luminance component of the image data to be processed in the image is at a low level, the level of this luminance component is not changed (image quality processing is performed); It can be carried out.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and various modifications are possible.

For example, the reference value X may be configured to be variable to a desired value, or may be configured to be set corresponding to a comparison value of the luminance signals Y and y.

The correction described in step S4 is based on the color difference signal RY
, B-Y may be performed.

Further, the present invention may be installed in a digital electronic still camera, or may be incorporated into various video equipment such as a color printer.

Furthermore, the luminance/color difference separation circuit is not limited to an analog system, but may be a digital system. If a digital method is adopted, it may be installed before the D/A converter 17.

(Effects of the Invention) As explained above, the digital image processing device according to the present invention provides: - a part of image data forming an image;
The luminance component of the image data to be processed for image quality processing is compared with a reference value, and if the luminance component is less than the comparison value, the comparison value between this luminance component and the luminance component of the reference color is used as the color difference signal of the reference color. The image data to be processed is processed using the color difference signal obtained by multiplying the .

Therefore, even if the luminance component of the image data to be processed is at a low level, image quality processing is performed using the color difference signal corrected according to this luminance component, so the luminance of the image quality-processed portion changes significantly. There's nothing to do. Therefore, it is possible to perform image quality processing on a desired portion of the - image without changing the brightness.

Therefore, it is possible to reproduce images that have been subjected to various types of image quality processing, so that it is possible to improve the functions of various video devices and make them multifunctional.

[Brief explanation of the drawing]

1 and 2 show an embodiment of a digital image processing device to which the present invention is applied, in which FIG. 1 is a flowchart explaining signal processing, and FIG. 2 is a circuit showing an example of a circuit configuration. The block diagram and FIG. 3 are image diagrams for explaining the relationship between the direct image to be processed and the sample image. Reference numeral 1 in the figure---blue sky in one image, 2-11---person in an image, 11---selector, 12--=-frame memory, 13----- -Control device, 14...-Address controller, 15--Ichien summer circuit, 16-"゛-' data controller, 17-...-D/A converter, 1111--Monitor, 51- S5-----Step.

Claims (1)

[Scope of Claims] In a digital image processing device configured to record or reproduce digitized image data forming one image, a portion of the image data that is to be processed into a desired color. When the first luminance component value in the image data to be processed and the second luminance component value in arbitrary reference color data to be replaced with the image data to be processed are compared, and this comparison value is a predetermined value or more. , a digital image processing device configured to create a new color difference signal from the color difference signal of the reference color data based on the comparison value, and replace the image data to be processed with the new color difference signal. .