JPH09258706A - Digital image color adjusting device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change a specific color (a before-change reference color) into anther specific color (an after-change reference color) with simple operation by changing each picture element color of an object image on the basis of a picture element color, a before-change reference color, an after-change reference color, and the difference between the picture element color and the before-change reference color. SOLUTION: A before-change reference color assigning means 3 pointassigning a picture element of a specific color (a before-change reference color) to be changed in color. An after-change reference color assigning means 6 assigns an after-change reference color and an adjustment ratio (a). An after-change picture elements color RGB value computing means 8 computes the after-change RGB value of each picture element color on the basis of the difference between the picture element color and the RGB value of the before-change reference color measured by a before-change reference color RGB value measuring means 4, the RGB value of the after-change reference color computed by an after-change reference color RGB value computing means 7, and the adjustment ratio (a). A color changed image display means 9 changes the color of each picture element of a color adjustment object image into a color corresponding to the computed after-change RGB value of each picture element color and displays it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital image color adjusting apparatus and method.

[0002]

[Prior art]

A color adjusting method for a digital image is a first method of adding color components (RGB values) to the entire target image, and an area of a specific color is designated from the target image, and RGB of the specified area is designated.
There is a second method or the like in which the values are changed to predetermined RGB values.

In the first method, since the color adjustment is performed by trial and error, there is a problem that it is difficult to change a predetermined specific color to another predetermined specific color.

In the second method, when the color is continuously changing, it is difficult to accurately specify the area of the specific color, and the color of the boundary portion of the area becomes discontinuous after adjustment, resulting in non-uniformity. There is the problem of natural colors.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a predetermined specific color (color before reference change) can be changed to another specific color (color after reference change) with a very simple operation. ,
Since the pixel colors other than the reference pre-change color are also changed according to the difference between the pixel color and the reference pre-change color, a color adjusting device for a digital image that can obtain an image in which the color continuously changes at the color boundary portion. And to provide a method.

[0007]

In a color adjusting apparatus for a digital image according to the present invention, a pre-reference-change color designating means for designating points of a specific color to be color-changed from a target image as a pre-reference-change color, point. A post-reference-change color setting means for setting a post-change color to a designated pre-reference-change color as a post-reference-change color, and each pixel color of the target image to the corresponding pixel color, pre-reference-change color, and post-reference-change color. A color changing unit that changes based on the color and the difference between the pixel color and the reference pre-change color is provided.

As the color changing means, for example, one that changes each pixel color of the target image so that it becomes closer to the color after the reference change as the difference between the pixel color and the color before the reference change is smaller.

More specifically, as the color changing means, arbitrary pixel colors of the target image are R _XY , G _XY and B _XY , pre-reference change colors are R ₀ , G ₀ and B ₀ , and post-reference change colors. To R ₁ , G ₁ , B
₁ , the adjustment rate is a, and the pixel color after the change with respect to the arbitrary pixel color is R _XY ', G _XY ', B _XY '
8 and 9, a means for calculating the pixel color R _XY ′, G _XY ′, B _XY ′ after the change for the arbitrary pixel color, and a pixel color R _XY ′, which has calculated the arbitrary pixel color.
What has a means for changing to G _XY ', B _XY ' is used.

[0010]

(Equation 7)

[0011]

(Equation 8)

[0012]

[Equation 9]

The color adjusting method for a digital image according to the present invention includes a first step of designating a point of a specific color to be color-modified from a target image as a reference pre-change color, and a post-change color of the point-designated reference pre-change color. Based on the pixel color of the target image, the color before the reference change, the color after the reference change, and the difference between the pixel color and the color before the reference change. It has a third step to change

As the third step, for example, one in which each pixel color of the target image is changed so as to be closer to the color after the reference change as the difference between the pixel color and the color before the reference change is smaller is used.

More specifically, as the third step,
R is the arbitrary pixel color of the target image_XY, G _XY, B_XY, Standard change
R in front color₀, G₀, B₀, R after changing the standard₁, G₁,
B₁, The adjustment rate is a, after the change for the above arbitrary pixel color
R is the pixel color_XY’, G_XY’, B _XY’
Based on 0, 11 and 12
Pixel color after change R_XY’, G_XY’, B_XY’Calculate
Step and pixel color calculated from the above arbitrary pixel color
R_XY’, G_XY’, B_XY’
One is used.

[0016]

(Equation 10)

[0017]

[Equation 11]

[0018]

(Equation 12)

According to the present invention, the predetermined specific color (color before reference change) can be changed to another specific color (color after reference change) by a very simple operation. Further, the pixel color other than the reference pre-change color is also changed according to the difference between the pixel color and the reference pre-change color, so that an image in which the color continuously changes at the color boundary portion can be obtained.

[0020]

Embodiments of the present invention will be described below.

In the color adjusting device, the operator designates a pixel of a specific color (hereinafter, referred to as a color before the reference is changed) in the target image displayed on a personal computer or the like, and the changed color (hereinafter, after the reference is changed). This is a device for changing the color before the reference change to the color after the reference change by setting the color) on the color editor screen. Each pixel color other than the point-designated pixel in the target image is a color determined based on the pixel color, the color before the reference change, the color after the reference change, and the difference between the pixel color and the color before the reference change. Can be changed.

FIG. 1 functionally shows the structure of the color adjusting apparatus.

The color adjustment area selection means 2 is the image display means 1.
From the image displayed by, the color adjustment area (hereinafter,
This is for selecting a color adjustment target image).
The color adjustment area selection means 2 is used, for example, when one of the object images is selected when the displayed image contains two object images.

The pre-reference-change color designating means 3 sets the color adjustment target image selected by the color adjustment area selecting means 2 to
This is for designating a point of a pixel of a specific color (color before reference change) whose color is to be changed.

The pre-reference color RGB value measuring means 4 measures the RGB value of the pixel designated by the point.
That is, the RGB value (R ₀ , G ₀ , B ₀ ) of the color before the reference change
Is measured.

The color editor display means 5 displays a color editor screen including a color chart in order to set the changed color (reference changed color) and the adjustment rate a with respect to the reference pre-change color.

The post-reference-change color designating means 6 designates the post-change color (the post-reference-change color) and the adjustment rate a with respect to the pre-reference-change color based on the displayed color editor screen. The color after the reference change and the adjustment rate a are set by the color editor display means 5 and the after-reference change color designating means 6.

After the reference is changed, the color RGB value calculating means 7
Of the standard color after the change designated by the changed color designation means 6
RGB value (R₁, G₁, B₁) Is calculated.
The changed pixel color RGB value calculation unit 8
RGB value (R_XY’, G_XY’,
B_XY') To the pixel color (R_XY, G_XY, B_XY) And before changing standards
RGB value of color (R₀, G₀, B₀) And the standard change
RGB value of the rear color (R ₁, G₁, B₁) And the adjustment rate a
It is calculated based on.

The color change image display means 9 changes the color (R _XY , G _XY , B _XY ) of each pixel of the color adjustment target image to the pixel color R after the change.
The color is changed and displayed in accordance with the RGB value (R _XY ', G _XY ', B _XY ') after the change of each pixel color calculated by the GB value calculating means 8.

FIG. 2 shows an example of a color editor screen displayed by the color editor display means 5.

The color editor screen is a hue palette 21 for displaying various hues in color and for designating the hue of the color after the reference change, and a hue selected from the hue palette 21. The color chart 22 for displaying the colors that the user has, the color chart 22 for designating the color after the standard change, the pre-reference color display area 23 for displaying the color before the standard change in color, and the color after the standard change designated from the color chart 22 for the color The color display section 24 after the reference change, the buttons 25, 26 for designating the adjustment rate a, the button 25,
It includes a graph display unit 27 for displaying a designated by 26 such that it can be intuitively understood.

The color displayed on the color chart 22 has the saturation changed in the horizontal axis direction and the lightness changed in the vertical axis direction. The designation of the hue from the hue palette 21 is performed by moving the triangle (Δ) pointer P1 with the mouse. To specify the color after changing the standard from the color chart 22, use the mouse to specify a square (□) pointer P1.
By moving and clicking.

The graph displayed on the graph display unit 27 is a symmetrical mountain-shaped normal curve and has a specified adjustment rate a.
Is large (a = a1), the width of the mountain becomes large as shown by g1 in FIG. 3, and when the designated a becomes small (a = a2), the width becomes narrow as shown by g2 in FIG. Become.

FIG. 4 shows a color adjustment processing procedure.

First, an image is displayed by the image display means 1 (step 1).

The operator judges whether or not it is necessary to select a color adjustment area from the image displayed by the image display means 1, and when it is necessary to select the color adjustment area, the color adjustment area is selected. A color adjustment area is selected using the selection unit 2. For example, a color adjustment target image is selected using a selection tool.

When the color adjustment area is selected (YES in step 2), the selected area is recognized as the color adjustment area (step 3). If the color adjustment area is not selected, the entire display image is recognized as the color adjustment area (step 4).

After that, the operator uses the pre-reference-change color designating means 3 to designate the point of the pixel of the specific color (pre-reference-change color) whose color is to be changed from the color adjustment target image. For example, after moving the pointer to the pixel of the color before the reference change with the mouse, click. In this way, when the pixel of the color before the reference change is designated (step 5), the color RG before the reference change is specified.
The RGB value (R ₀ , G ₀ , B ₀ ) of the color before the reference change is measured by the B value measuring means 4 (step 6).

Next, in response to the operator's operation, the color editor display means 5 displays a color editor screen including a color chart (step 7).

The operator uses the post-reference-change color designating means 6 to designate the post-change color (the post-reference-change color) with respect to the pre-reference-change color based on the color editor, and also designates the adjustment rate a.

In this way, when the reference-changed color and the adjustment rate are designated (step 8), the reference-changed color RGB
The RGB value (R ₁ , R ₁ ,
G ₁ , B ₁ ) is calculated (step 9).

Then, the changed pixel color RGB value calculation means 8
The RGB values (R _XY ', G _XY ', B _XY ') after the change for each pixel color in the color adjustment target image are
_XY , G _XY , B _XY ) and RGB values (R ₀ , G) of the color before the reference change
₀ , B ₀ ) and the RGB value (R ₁ ,
G ₁ and B ₁ ) and the adjustment rate a are calculated (step 10).

That is, the RGB values (R _XY ′, G _XY ′, B _XY ′) after the change of each pixel color in the color adjustment target image are calculated based on the following formulas 13, 14, and 15.

[0044]

(Equation 13)

[0045]

[Equation 14]

[0046]

(Equation 15) Each time the RGB value after the change of the pixel color in the color adjustment target image is calculated, the color change image display means 9 changes the color of the pixel to the calculated RGB value (step 1).
1).

When the processes of steps 10 and 11 are performed for all the pixels in the color adjustment target image (YES in step 12), the color adjustment process ends. .

As can be seen from the above equations 13 to 15, when the pixel color (R _XY , G _XY , B _XY ) is the color before the reference change, the pixel color (R _XY , G _XY , B _XY ) and the reference color RG of the color before change
The difference D from the B value (R ₀ , G ₀ , B ₀ ) is “0”, and e
^{-(1 / a) D} becomes "1". Therefore, the pixel color (R _XY ,
A pixel in which G _XY , B _XY ) is the color before reference change (R ₀ , G ₀ , B ₀ ) becomes the color after reference change (R ₁ , G ₁ , B ₁ ).

The pixel color (R_XY, G_XY, B_XY) And standards
RGB value (R₀, G₀, B₀) Is large D
E^{-(1 / a) D}Approaches "0" and the difference D is small
E^{-(1 / a) D}Approaches "1". Therefore,
RGB value (R ₀, G₀, B₀) Far color
Pixel (R_XY, G_XY, B_XY) Is the original pixel color (R_XY, G
_XY, B_XY) Is close to the color. On the contrary, the RG of the color before the standard change
B value (R₀, G₀, B ₀) Close to the pixel (R_XY,
G_XY, B_XY) Is the color (R₁, G₁, B₁)
Get closer.

When the difference D between the pixel color (R _XY , G _XY , B _XY ) and the RGB value (R ₀ , G ₀ , B ₀ ) of the color before the reference change is the same, the adjustment rate a is small. I see e- ^{(1 / a) D} is "
As the adjustment ratio a approaches 0 "and the adjustment rate a increases, e
^{-(1 / a) D} approaches "1". Therefore, when the adjustment rate a is set small, the difference D between the pixel color (R _XY , G _XY , B _XY ) and the RGB value (R ₀ , G ₀ , B ₀ ) of the color before the reference change is smaller than the actual difference. Is also considered to be large, the degree of color change is small for pixel colors other than the reference pre-change color. On the contrary, when the adjustment rate a is set large, the difference D between the pixel color (R _XY , G _XY , B _XY ) and the RGB value (R ₀ , G ₀ , B ₀ ) of the color before the reference change is larger than the actual difference. Since it is considered that the pixel color becomes smaller, the degree of color change becomes larger for the pixel colors other than the pre-reference-change color.

Therefore, when only the pixel color close to the color before the reference change is desired to be changed, the adjustment rate a is set small, and when the pixel color far from the color before the reference change is also to be changed, the adjustment rate a is set large. To be done.

In the above embodiment, the operation is very simple.
Then, the predetermined specific color (the color before the standard change (R ₀, G₀,
B₀)) To other specific colors (colors after changing the standard (R₁, G₁,
B₁)) Can be changed. Also, the color before the standard change
Each pixel color other than (R_XY, G_XY, B_XY) Is also the pixel color
(R_XY, G_XY, B_XY) And the color before the standard change (R₀, G₀, B
₀) Is changed according to the difference between the
An image with continuously changing colors is obtained.

[0053]

According to the present invention, a predetermined specific color (color before reference change) can be changed to another specific color (color after reference change) by a very simple operation. Moreover, the pixel color other than the reference pre-change color is also changed according to the difference between the pixel color and the reference pre-change color, so that an image in which the color continuously changes at the color boundary portion can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a color adjustment device.

FIG. 2 is a schematic diagram showing an example of a color editor screen.

FIG. 3 is a schematic diagram showing a graph display of an adjustment rate.

FIG. 4 is a flowchart showing a color adjustment procedure.

[Explanation of symbols]

 1 image display means 2 color adjustment area selection means 3 pre-change color specification means 4 pre-change color RGB value measurement means 5 color editor display means 6 post-change color specification means 7 post-change color RGB value calculation means 8 after change Pixel color RGB value calculation means 9 color changed image display means

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H04N 1/46 G06F 15/66 310 H04N 1/46 C

Claims (6)

[Claims] 1. A pre-reference-change color designating means for designating points of a specific color to be color-changed from a target image as a pre-reference-change color, and a post-change color for the point-designated standard pre-change color,
After-reference-color setting means for setting as the after-reference-change color, and each pixel color of the target image, the pixel color, the before-reference-change color, the after-reference-change color, and the difference between the pixel color and the before-reference-change color A color adjusting device for a digital image, comprising: 2. The color changing means sets each pixel color of the target image to
2. The color adjusting device for a digital image according to claim 1, wherein the smaller the difference between the pixel color and the color before the reference change, the closer to the color after the reference change. 3. An arbitrary pixel color of a target image is set to R _XY , G _XY ,
B _XY , R ₀ , G ₀ , B _{0 for} the color before the reference change, R ₁ , G ₁ , B _{1 for} the color after the reference change, the adjustment rate a, and the pixel color after the change for the arbitrary pixel color is R _{XY Assuming} “, G _XY ”, and B _XY ”, the color changing means _calculates the pixel color R _XY ′, after the change with respect to the arbitrary pixel color, based on the following formulas 1, 2, and 3.
G _XY ', B _XY' means for calculating, and the arbitrary pixel pixel color R _XY, which is calculated color ', G _XY', one of the claims 1 and 2 is provided with a means for changing the B _XY ' A digital image color adjustment apparatus according to claim 1. [Equation 1] [Equation 2] (Equation 3) 4. A first step of designating points of a specific color to be color-modified from a target image as a standard pre-change color, and a post-modification color for the designated standard pre-change color,
The second step of setting as the color after the reference change, and each pixel color of the target image is changed based on the pixel color, the color before the reference change, the color after the reference change, and the difference between the pixel color and the color before the reference change. A color adjusting method for a digital image, comprising: a third step. 5. The third step is to change each pixel color of the target image so that the smaller the difference between the pixel color and the color before the reference change, the closer to the color after the reference change.
A method for color adjustment of a digital image according to. 6. An arbitrary pixel color of a target image is set to R _XY , G _XY ,
B _XY , R ₀ , G ₀ , B _{0 for} the color before the reference change, R ₁ , G ₁ , B _{1 for} the color after the reference change, the adjustment rate a, and the pixel color after the change for the arbitrary pixel color is R _{XY Assuming} “, G _XY ”, B _XY ”, the third step is based on the following equations 4, 5 and 6:
The pixel color R _XY 'after the change with respect to the arbitrary pixel color,
G _XY ', B _XY' step for calculating a, and the arbitrary pixel pixel color R _XY, which is calculated color ', G _XY', one of the claims 4 and 5 comprises a step of changing the B _XY ' A method for adjusting the color of a digital image according to claim 1. (Equation 4) (Equation 5) (Equation 6)