JPH0378669B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an image processing device having a function of changing the color of a desired area.

<Prior Art> In the past, changing colors has often been done as one of image processing techniques. For example, by changing only the color data of areas corresponding to leaves in a landscape image from green to yellow, a new image with a flavor different from the original image has been generated. In short, for this process, each of the R (red), G (green), and B (blue) data of the pixels constituting each image may be replaced with different data. However, if it is attempted to rewrite the data of each pixel each time the color is changed, the number of accesses from processing hardware such as a CPU to the image memory will naturally increase.

Furthermore, in the process of changing the color by rewriting the image memory, once the image data is changed, the original data is erased. Therefore, it is not suitable for a system that frequently compares the original color and the changed color, such as color change simulation.

For this reason, in an image processing device that frequently uses color changes, a lookup table memory is provided between the image memory and the display device, and the output from the image memory is converted by the lookup table memory and output to the display device. method is often used. With this image processing device, it is possible to change colors at high speed by simply rewriting the contents of the lookup table memory without changing the contents of the image memory.

Conventionally, the following two methods have been commonly used to input original images to such image processing apparatuses.

(1) One method is to write color information directly and interactively into the image memory while checking the contents of the image memory on a display device. In this method, first, a color to be written is selected, and then the coordinate input means is used to sequentially input the color. In other words, this is a method of ``drawing a picture'' on an image processing device.

(2) The other method is to input a black and white line drawing into an image processing device using a camera, scanner, etc., and then use a function such as filling in to input colors into the image processing device. In other words, this is a method in which figures and information are input outside the image processing apparatus (for example, by drawing pictures on paper with a magic trick), and color information is input using the image processing apparatus.

What these two methods have in common is that they both involve inputting color information within the image processing device. Therefore, with these two methods, it is easy to find out what value of color information is assigned to which part of the image, and the color can be easily changed.

For example, FIGS. 7a to 7b show the input of color information using the method (2) above. FIG. 7a shows an example in which a black and white line drawing is input, and FIG. 7b shows an example in which it is colored using the filling method. For example, assume that data for C ₁ is written in the shaded area and data C ₂ is written in the dotted area in the image memory. As a result, if you want to change the color of the shaded area, the output from the image memory
All you have to do is convert C ₁ to another color using lookup table memory.

However, images that are difficult to input using the conventional image input methods described above include full-color images such as photographs and TV images. Images such as photographs have a very large number of colors, and each pixel often has a slightly different color. It is very difficult to create such an image by inputting colors within an image processing device. In such a case, it is better to color separate the original picture, such as a photograph or TV image, and input it directly into the image memory. The procedure for changing the color of an image input using this method is as follows.

That is, if you input an image of a real apple using a TV camera and want to change the color of this apple, you first need to input which area is the apple to the image processing device. This is because if the same color as the apple is contained in different places in the original picture, it is necessary to distinguish between them.

An image processing device that easily extracts a specific area from an image in full color was recently invented by the present inventors. This image processing device includes a dual-purpose memory for storing density information of each pixel constituting an image and label information indicating whether a region has been extracted or not, and a memory for inputting a desired threshold value regarding the density information. a coordinate input means for inputting predetermined coordinates in the image;
A look-up table is defined for converting the concentration information from the dual-purpose memory based on the threshold input from the threshold input means, and a look-up table for converting the input information from the dual-purpose memory is determined according to the look-up table. an up-table memory, a display means for displaying an image based on the output of the look-up table memory, and the above-mentioned label of the pixel in the area to be extracted determined by the above-mentioned threshold value and specified by the above-mentioned coordinate input means. and an arithmetic processing unit that rewrites information, converts the output signal representing the characteristic level of each pixel of the original image from the dual-purpose memory in the lookup table memory, and converts the output signal representing the characteristic level of each pixel of the original image from the dual-purpose memory into the threshold value input from the threshold value input means. The area to be extracted, which is determined by I try to do it.

<Problems to be Solved by the Invention> However, in the conventional image processing apparatus described above, it is not so easy to change the color after performing area extraction.
This is because the area of an apple contains a large number of different types of color information, from bright red to dark red, even though the color red is the same. Therefore, for example, if 100 types of colors close to red are included, in order to change the color of the apple area, at least
There is a problem in that it is necessary to set the lookup table memory for 100 types of input.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to change the color of pixels included in a specific area of an image by inputting a reference color and a target color so that the color of the pixels included in that area is adjusted to a certain level between the target color and the reference color according to the shade of the color of the pixels included in that area. The purpose is to automatically change colors easily and quickly to match the relationship.

<Means for Solving the Problems> The present invention provides a dual-purpose memory that stores density information of each pixel constituting an image and/or label information for determining an area depending on the case, and a dual-purpose memory as described above. a look-up table memory for converting and outputting input information from the look-up table memory; and display means for displaying an image based on the output of the look-up table memory; In an image processing device that changes the color of a specific area of a layer by rewriting the density information of the area, a predetermined pixel in the specific area on the image whose color is to be changed is specified, and the density information of that pixel is changed. a coordinate input means for inputting a reference color and label information; a color input means for inputting a target color to be changed for the reference color specified by the coordinate input means; and a reference color of the pixel input by the coordinate input means. rewrites the density information in the lookup table memory so as to change the color to the target color, and also updates the density information in the lookup table memory of the pixel included in the specific area having the specific label information specified by the coordinate input means. The present invention is characterized by comprising a lookup table color setting means that automatically calculates and rewrites the color so as to have a certain relationship with the target color according to the shade of the color indicated by the density information.

<Operation> When changing the color of a full-color image, first, a reference color serving as a reference for color change is input from a specific location of the full-color image using the coordinate input means. Next, a target color representing the color to be changed is input using the color input means.
Then, the lookup table color setting means automatically calculates to which other color to change based on the purpose, the contents of the lookup table memory are rewritten, and the color is changed.

<Example> Hereinafter, the present invention will be explained in detail. Figure 1 shows full-color images of R (red), G (green),
FIG. 2 is a block diagram of an image processing device that separates an image into three components of B (blue) and stores them. This image processing device is equipped with a dual-purpose memory 15 of 8 bits each for RGB.
This dual-purpose memory 15 stores density information constituting an image and label information for identifying an area, depending on the case. The output of the dual-purpose memory 15 is connected to the address of the lookup table memory 16, and the output of the lookup table memory 16 is connected to the address of the gate circuit 1.
It is connected to the D/A converter 18 via 7.

The lookup table memory 16 is bus 1.
4. Accessed by microprocessor 13 through gate 20. The above microprocessor 13
includes a lookup table color setting means for calculating and rewriting the density information in the lookup table memory 16, which will be described later.

Further, the output (video anlog signal) of the D/A converter 18 is sent to a display 19, where an image is displayed. The dual-purpose memory 15 and main memory 12 are accessed by the microprocessor 13 via the bus 14. Coordinate input means 21
is accessed from the microprocessor 13 through the bus 14, and by inputting specific coordinates on the image, it is possible to input a color as a reference for color change. The color input means 11 is accessed by the microprocessor 13 via the bus 14, and can input a desired color to which the reference color is to be changed.

Next, the processing of this device will be explained.

First, an image is input into the dual-purpose memory 15 using a scanner, a TV camera, or other means. At this stage, information of 8 bits each of RGB is stored in the dual-purpose memory 15 for each dot. Next, as an example, the upper 6 bits of the dual-purpose memory 15 are used for image information, and the lower 2 bits are used for label information regarding the area. FIG. 2 shows the dual-purpose memory set in this way. Then, if one color component of RGB is represented by K, the K component (K = r, g or b)
The information stored in the dual-purpose memory 15 is gray information.
i _K (0≦i _K <2 ⁶ ) and label information l (0≦l<2 ² ), and the output of the dual-purpose memory 15 becomes 2 ² ×i _K +l. When changing the color, the lookup table color setting means sets the contents of the lookup table memory 16 as follows.

Here, x is the output of the dual-purpose memory 15, that is, the input of the lookup table memory 16, f _K (x)
is the output of the lookup table memory 16 for the K component.

f _K (x)=f _K ⁽⁰⁾ (x) (when xmod 2 ² = 0) = f _K ⁽¹⁾ (x) (when xmod 2 ² = 1) = f _K ⁽²⁾ (x) (When xmod 2 ² = 2) =f _K ⁽³⁾ (x) (When xmod 2 ₂ = 3) The function f _K ^(l ′ ⁾ (x) (l ′ = 0, 1, 2, 3) is , are functions that determine the color of areas whose label information is 0, 1, 2, and 3, respectively. That is, by changing the function f _K ^(l ′ ⁾ corresponding to each label, it is possible to change the color of each area independently.

FIG. 3a shows an example of a full-color image with four labels: 0, 1, 2, and 3. Specifically, the color of a certain area in this area is changed as follows.

(1) Enter the reference color input mode using the mode selection means. In the reference color input mode, the coordinate input means 21
Use to specify a point on the image for which color you want to change, and input the color density information (Ir, Ig, Ib) of that point and the label information _l0 of that point.

FIG. 3b shows how a cursor that moves in accordance with the coordinate input means 21 is displayed on the screen and a reference color is input.

(2) Enter the target color input mode using the mode selection means. In the target color input mode, the color input means 11 inputs the color to which the point specified in the reference color input is to be changed.
Enter. That color is called the target color, (Dr,
Dg, Db). There are several ways to input the target color, such as calling up a palette on the screen and selecting a color from it, inputting the color components numerically, or displaying the color components in a graph and inputting by changing the graph. Conceivable.

(3) Next, change the lookup table 16. Label information for the area whose color will be changed in step (1)
Since l ₀ is obtained, the corresponding function f _K ^(l ₀ ⁾
Change (x) as follows. In the following equation, i is the quotient of input x divided by 2 ² , that is, density information.
[ ] is a Gaussian symbol.

f _K ^(l ₀ ⁾ (x)=[D _K ×i/I _K ] (0≦i<I _K ) =D _K (i=I _K ) = [F×i−I _K /2 ⁶ −I _K +D _K ×2 ⁶ −i/2 ⁶ −I _K ] (
I _K <i≦2 ⁶ ) F is the maximum value of the output of the lookup table memory 16.

Figures 4a, b, and c show the form of the function expressed by the above equation.

By setting the function f _K ^(l ₀ ⁾ (x) in this manner, the area corresponding to the label information l ₀ is displayed with its color changed as follows. First, the coordinate point where the reference color is input is displayed in the target color. Furthermore, points with a color density lighter than the reference color are displayed brighter, and dark points are displayed darker, resulting in a visually natural color change.

As described above, by using the method of the above embodiment, the color of a full-color image can be easily and quickly changed by simply inputting coordinates for inputting a reference color and inputting a color for inputting a target color.

The present invention can have various applications. for example,
When inputting a reference color, the example in which the color information of one point inputted by the coordinate input means 21 is used as the reference color has been described above. Another option is to use color. This method is effective when the original image contains a lot of noise.

In addition, in the above example, as shown in Figure 4, the contents of the lookup table memory are set by linearly interpolating between the target color, a color with high brightness, and a color with low brightness. However, a method of interpolating using a curve can also be considered.

Further, in the above example, one reference color and one target color were input, but a method of inputting multiple sets of these can be considered. In this case, since a plurality of reference colors and target colors are input as shown in FIG. 5, for example, a straight line or curve connecting these points can be calculated and a lookup table can be set. In Figure 5, I ₁ , I ₂ ,
I ₃ and I ₄ are the K components of the four reference colors, D ₁ to _{D 4} are the K components of the target color, the horizontal axis is the input, and the vertical axis is the output f _K ^(l ₀ ⁾ .

In addition, in the above example, the color component with the highest brightness is output for the largest input, and the color component with the lowest brightness is output for the smallest input. A method is also conceivable in which the information can also be set using the color input means 11. Let these light colors and dark colors be (Fr, Fg, Fb) and (Er, Eg, Eb), respectively. Using this color component, lookup table memory 16
are set as shown in FIG. 6 a, b, and c.

If you do this, the number of input data will increase, but
It is possible to adjust the colors of dark shadow areas and bright highlight areas.

In addition, in the above example, we explained the case where there is four label information, but if the amount of label information is larger, or even if there is no label information, it is possible to use the standard color and target color. Color change methods are applicable.

<Effects of the Invention> As is clear from the above, the image processing apparatus of the present invention is equipped with a coordinate input means, a color input means, and a lookup table color setting means, and is capable of inputting density information of a specific area having a large number of colors. It automatically calculates a certain relationship between the target color and the reference color according to the shade of the color, and rewrites the density information in the lookup table memory, making it easier to change the color in areas where shades are distributed. It's fast and easy.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an image processing apparatus according to an embodiment of the present invention, FIG. 2 is a diagram explaining the contents of a dual-purpose memory and a lookup table memory, and FIGS. 3 a and b
is a diagram showing a full-color image with labels,
FIGS. 4a, b, c, 5, and 6 a, b, and c are diagrams of each function of the lookup table color setting means, and FIG. 7 is a diagram illustrating conventional color changing. 11...Color input means, 12...Main storage device, 1
3...Microprocessor, 14...Bus, 15
... Dual-purpose memory, 16... Lookup table memory, 17... Gate circuit, 18... D/A converter, 19... Display, 20... Gate circuit for reading and writing lookup table, 21... Coordinate input means .

Claims (1)

[Scope of Claims] 1. A dual-purpose memory for storing density information of each pixel constituting an image and/or label information for determining an area depending on the case; and a dual-purpose memory for converting input information from the dual-purpose memory. and a display means for displaying an image based on the output of the look-up table memory; In an image processing device configured to change the color of a specific area of an image, specify a predetermined pixel in the specific area on the image where the color is to be changed, and input the reference color and label information that are the density information of that pixel. a coordinate input means; a color input means for inputting a target color to which the reference color specified by the coordinate input means is to be changed; In addition to rewriting the density information in the lookup table memory, the density information in the lookup table memory of the pixel included in the specific area having the specific label information specified by the coordinate input means is changed to the shade of color indicated by the density information. 1. An image processing apparatus comprising: a lookup table color setting means that automatically calculates and rewrites a lookup table color so as to have a certain relationship with the target color according to the color. 2. In the image processing apparatus according to claim 1, the lookup table color setting means averages density information of pixels around the coordinates inputted by the coordinate inputting means, and calculates the average value as described above. An image processing apparatus characterized in that density information in a lookup table memory is rewritten as a reference color. 3. In the image processing apparatus according to claim 1, the lookup table color setting means is configured to input a bright color input by the color input means, in addition to the density information representing the reference color and the target color. An image processing apparatus characterized in that density information in the lookup table memory is rewritten based on density information representing a dark color.