KR950007129B1 - Color picture display method and circuit therefor on computer screen - Google Patents

Abstract

The device can display images of mono, 16 color, 256 color and 24 bit color regardless of a video device deriver of a computer. It provides device derivers (204) according to videos at a computer graphic environment (201) and provides a graphic display system (202) by unifying interfaces of each of the device derivers (204). So, the graphic display system (202) can display images to the display device of the computer through the interface (203).

Description

Color Image Display Method and Circuit in Computer Graphic Environment

1 is a general computer system diagram

Figure 2 shows the computer graphics environment and device driver configuration

3 is a conventional flow chart

4 is a flow chart according to the present invention

5 is a detailed flowchart of color value conversion of the fourth process of FIG.

The present invention relates to a color image display method and circuit in a computer graphics environment.

Recently, various kinds of images have been developed from the old black and white color to 16 colors, 256 colors, 24 bits (160,000 kinds), etc. according to various color demands of users. Among the video boards that support color in the display device 103 in the computer system as shown in FIG. 1, black and white and 16 or 256 color display capability are widely used, and a board having a 24-bit color display capability is used. Not yet generalized. Also, due to the variety of video boards adopted by each computer, the implementation of the graphic display function is different for each video board, and the graphic display system has to make a device driver for each board. To solve this problem, a unified computer graphics environment has been proposed. That is, by providing the device driver 204 according to the video in the computer graphics environment 201 as shown in FIG. 2 and unifying the interface of each device driver 204 and providing the graphic display system 202 to the graphic display system 202. ) Can be displayed on the display device of the computer via the interface 203.

An example of processing of the graphic display system 202 in the graphic environment 201 as shown in FIG. 2 is shown in FIG. 3.

In step (3a), images of various colors are first read into the memory 106 to form an image memory. At this time, the configuration of the image memory on the memory 106 is formed in accordance with the configuration format of the color image. For example, in the case of a black and white image, since one pixel forms one bit, one byte represents eight pixels. The 32 (horizontal) x 64 (vertical) images are arranged on a memory of 4 bytes in width and 64 lines, that is, 4 x 64 = 256 bytes. In the case of 16 colors, 4 bits represent one pixel, so 1 byte represents two pixels, arranged in a predetermined form on 32/2 = 16 bytes of Burbi and 64 lines, that is, 16 × 64 = 1024 bytes of memory 106. do. In the case of 256 colors, one byte represents one pixel, and thus 32 × 64 = 2048 bytes is formed in the memory 106. In the case of a 24-byte color, three bytes of red, green, and blue represent one pixel. 3 x 64 = 6144 bytes are arranged on the memory 106 in a predetermined arrangement.

In step (3b), a color table is created using the color information used in the image. There are 16 color tables for 16 colors, and 256 color tables for 256 colors. There is no color table for only 24-bit colors.

In the process (3c), in order to display the image of the image memory prepared in the process (3a) on the display device 103, it is first necessary to change the memory structure that the video board 206 can represent. That is, when the actual video board 206 can display only 16 colors Considering the case where the read image is 256 colors or 24-bit colors, the memory structure of the 16 color video board 206 is red, green, and blue. It consists of four planes representing the intensity and the intensity, one bit of each plan represents one pixel, and in actual display, each bit of the four plans is combined to reproduce the color of one pixel. Therefore, the contents of the image memory should be converted to the memory configuration of the video board 206, and at the same time, the color of the image should be limited to 16 colors to find and replace the nearest color. Since this operation is automatically handled by the interface 203 provided in the computer graphics environment 201, the graphic display system 202 only uses the corresponding interface 203.

The data on the image memory changed in step (3d) and in step (3b) is displayed on the actual display device 103. This also uses the interface 203 used in the computer graphics environment 201. However, as shown in the description of step (3b) above, the same color as that displayed on the 16-color video board 206 for a 256 color or 24-bit color image, that is, the number of colors of the original image is greater than the number of colors that can be displayed on the video board. In many cases, there are two fatal drawbacks.

First, in the case of using the interface 203 provided in the computer graphics environment 201, a forced color value is modified to show a significant difference from the original image.

Second, an approximate color value search is made to find the color value closest to the original color value, which takes considerable time because it searches the space on the RGB three-dimensional. In particular, the more colors the video board 206 can represent, the longer it takes. In other words, if the 256 color or the 24-bit color is changed to 16 colors, the number of search indexes is 16 per pixel, whereas when the 24-bit color is converted to 256 colors, the number of search indexes is 256 per pixel. This delay in time increases logarithmically as the size of the image increases and the number of supported colors increases.

It is therefore an object of the present invention to provide a method and circuit for displaying images of monochrome, 16, 256, and 24-bit colors (160,000 colors) regardless of the video device driver of a computer in a computer graphics environment.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

4 is a flow chart according to the present invention, in which a first process of reading an image from an image memory and a first color number of a picture obtained in the first process and a second color number that can be represented by a video board (Device Color). In the second process having a) and the first and second color (Device, Color) obtained from the second process and larger than 256 of the number of colors (Device Color) that the video board can represent and the first A third process of comparing whether a color is less than or equal to a second color, and in the third process, the second color of the device is not greater than 256 and the second color of the device ) Is greater than or equal to the first color (Color), the fourth process of creating a unique 256 color table to change the color value of the image memory in the multi-value pseudo-gradation, and the second color number (Device Color) in the third process ) Is greater than 256 and the first color is smaller than the second color As that of generating a color image by changing the image memory in the memory device structure from the output color values in the fourth step comprises a fifth step of displaying this case the.

FIG. 5 is a concrete flow chart of the fourth process of FIG. 4, which increases the steps of the intensity levels of R, G, and B one by one, and the intensity level + B of the index [INDEX = (contrast level of R * G + G) * B). ], A process for constructing an independent color table for designating R, G, and B color table indexes, a matrix constructing process for constructing a pseudo-gradation matrix by using the generated values of the process for creating an original color table, and the process for constructing the matrix R, G, and B color values of the image memory of the image are obtained by using the pseudo-gradation matrix to obtain the color values of red 1, green 1, and blue 1 pseudo-graded using the color table. A color value conversion process is performed to obtain a new color index and replace it with the original value.

Therefore, if a specific embodiment of the present invention will be described in detail, the processes of (4a), (4g), (4h), (4i) of FIG. 4 described above (3a), (3b), Note that the treatment is performed in a similar manner to the processes of (3c) and (3d).

In step 4b, the cpu 101 obtains a first color number (Color) of the image to be displayed and a second color number (Device Color) that the video board can display. The first color number (Color) of the image is included in the information of the image file, and the second color number (Device Color) of the video board uses a function provided by the interface 203 of the computer graphics environment 201.

In step (4c) and (4d), it is determined whether the image memory is to be converted to (4e) or (4f). If the second color number is larger than 256, the video board 206 supports at least 4000 colors at the same time. If the first color number is less than or equal to the second color number Device Color, there is no problem even if the conventional method is applied.

This is a case where the color value of the image is larger than the number of colors that the video board 206 can represent in steps 4l and 4f. First, create your own 256 color tables. Each RGB is divided into appropriate contrast levels to form a table. For example, by combining the brightness of 256 levels of RGB with 7 levels of R, 7 levels of G, and 5 levels of B, 7 × 7 × 5 = 245 color combinations can be obtained. Use this color value to create a color table. The color value of the image memory is changed to the index of the color table by using the multi-value pseudo-gradation method using the next 256 color values. Through this process, the contents of the image memory are replaced with the pseudo-graded color values with the color values that can be represented by the video board 206. Therefore, the approximate color search search that is time-consuming in the prior art is not necessary, and the quality equivalent to the original image can be obtained by multi-value pseudo-gradation processing rather than coercion of color values.

Looking at the process of (4l) and (4f) in detail with reference to FIG. 5, (5a) shows how to create an original color table, and in step (5b) the pseudo-gradation matrix is created using the generated color table. Configure. Organizational pseudogradation is a good way to improve screen display and save time. The process (5c) obtains the color values of Red 1, Green 1, and Blue 1, which are pseudo-gradations using the pseudo-gradation matrix of the image memory, using the pseudo-gradation matrix, and uses these values to index the color values in the color table. Obtain the New Color Index. This value is replaced with the corresponding original color value in the image memory. As can be seen, when the original image is a 24-bit RGB color, it represents one pixel. 3 bytes of RGB are required, whereas the index value converted by the above process has only 1 byte. do. Therefore, the saving effect of image memory can also be expected.

As described above, in the graphic display system in a computer graphic environment, the video board can overcome the limitation of the number of colors provided by pseudo gradation to save the quality of the original image and eliminate the time required to find the approximate color. It is possible to configure a graphic display system having a memory saving effect by reducing the size of the image memory.

Claims (5)

A color image display method in a computer graphics environment, comprising: a first process of reading a color image from an image memory, a first color of the image read in the first process, and a second color that can be represented by a video board In the second process of obtaining the number (Device Color) and the first and second color (Color, Device Color) obtained in the second process is greater than 256 of the number of colors (Device Color) that the video board can represent and A third process of comparing whether the first color is less than or equal to the second color and a second color number of the second color in the third process If (Device Color) is not greater than or equal to the first color (Color), the fourth process of creating an original 256 color table and changing the color value of the image memory with multilevel pseudo gradation, and the second color number in the third process (Device Color) is larger than 256 and the first color is the second color. Computer graphics environment, characterized in that when the color is less than or equal to the device color (5) is the process of generating the color of the image and the image memory is changed to the device memory structure from the output color value of the fourth process to display it Color image display method in The method according to claim 1, wherein the fourth process increments the contrast levels of R, G, and B one by one, and specifies an index [INDEX = (contrast level of R * G + G] * B). A process of creating a color table, which is an independent algorithm for designating an R, G, and B color table index, and a process of constructing a pseudo-gradation matrix using the generated values of the process of creating an original color table; Color values of Red 1, Green 1, and Blue 1, which are pseudo-graded colors of the color table using the pseudo-gradation matrix, using the pseudo-gradation matrix, are used to obtain the color value index from the color table. A color image display method in a computer graphics environment comprising a process of converting a color value to obtain a color index and replace the original value. In the image graphics display method in a computer graphics environment, multilevel pseudo-gradation is performed according to a step 1 of reading the image into the image memory, the step 2 of acquiring the number of colors of the image, and the color of the step 2; Step 3 of searching for the necessity of the step, step 4 of constructing a unique color table and performing multi-value pseudo-gradation according to the need, step 5 of making the color table of the image, and converting the image memory into a video board memory structure. And step 6 of displaying the converted picture memory. A color image display device in a computer graphics environment, comprising: image acquisition means for reading the image from an image memory, a first color number of a image read by the image acquisition means, and a second color number that can be represented by a video board The second color number calculating means for obtaining (Device Color) and the number of colors represented by the video board in the first and second color numbers (Color, Device Color) obtained by the first and second color number calculating means (Device Color) Comparison means for comparing the first color (Color) is less than or equal to the second color (Device Color), and the second color number (Device Color) in the comparison means Changing means for making an original 256 color table and changing it to a color value of an image memory by multi-valued pseudo gradation when the second color number (Device Color) is not greater than or equal to the first color number (Color); 2 color (Device Color) If it is larger than 256 and the first color is less than or equal to the second color, the color of the image is generated and the image memory is changed to the device memory structure from the axial color value of the generating means. A color image display device in a computer graphics environment, characterized in that it comprises a display means. The method according to claim 1, wherein the changing means increments the steps of the contrast levels of R, G, and B one by one, and specifies an index [INDEX = (contrast level of R * G + G] * B) of contrast level + B]. Independent color table creating means for designating R, G, and B color table indexes, matrix constituting means for constructing a pseudo-gradation matrix using the generated values of the original color table creating means, and image memory of the matrix constituting means. Color values of Red 1, Green 1, and Blue 1 that are pseudo-graded to the color of the color table using the pseudo-gradation matrix are obtained using the pseudo-gradation matrix, and the color color index, which is the color value index, is used in the color table. And a color value converting means for obtaining and replacing the original value.