JPS61233781A - Graphic display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a graphic processing device, and particularly to color display of objects.

[Background of the invention]

As described in Japanese Unexamined Patent Publication No. 59-129897, the conventional device stores luminance and color information of each pixel, or a device for indexing these from a color index table device, in a device that stores one stroke, that is, a frame buffer. The index values were memorized. However, due to the nature of human vision, which has high resolution for changes in brightness width and low resolution for changes in color at the same brightness, no consideration was given to reducing the capacity of the frame buffer. . For the properties related to visual perception, please refer to Chapter 2 of "Color Television Technology J (1966)" edited by the Television Society of Japan.

[Purpose of the invention]

The purpose of the present invention is to
, it is mentioned that the capacity of the frame buffer can be reduced.

[Summary of the invention]

As mentioned above, in human vision, the resolution when changing the color while keeping the brightness constant is significantly inferior to when changing the brightness. Separates color difference signals,
The overall band pressure m is determined by making the band of the color difference signal narrower than the band of the luminance signal. Assuming that the G and H signals output from the camera are Eo and Eo+Em, the luminance Ex is expressed by the following equation.

E T -0,30Em + 0.59Eo + 0.
11Em...(1) Two color difference signals Ex and E
e is 9 as follows.

Here, human vision has a perceptual ability for changes in El, which is E
It is higher than that of Q, and the band of El is wider than the band of Ea.

These signals are sent to the receiver. ET# on the receiving side
Ex, Eo, and El signals are determined from the EQt Es signal. That is, formulas (1) to (3) kEm.

Solving for Ea and EmK gives the following equation.

El=Br +0.96Et+0.63Ea
...(4) Ea = Ey -0,28Er-0,64
EQ...(5)E1±Ey L11B
t+1.70Eq...(6) Here %EQ
Assume that errors ΔQ and ΔA occur because ΔQ and El are transmitted in a narrow band. Em, Ea and Em on the receiving side in this case
is as follows.

& =Ey+0.96 (E!+ΔI) +0.63
(Eta+ΔQ)...(7) Ea = Ev-0,2
8CEt+ΔI)-0,64(EQ+ΔQ)...(8
) Em −& −Ll 1 (Et+ΔI)+L70(
Ea+ΔQ)...(9) The brightness is obtained by multiplying these signals by the visibility coefficients 0.30, 0.59, and 0.11t''.In other words, the brightness Ey of the reproduced image is calculated using equation (1). In this case, ΔF and ΔQ cancel each other out and do not affect the brightness of the reproduced image.Therefore, although color errors occur due to errors caused by narrowing the band of the color difference signal, There is no effect on the brightness.For the NTSC system, please refer to Chapter 3 of the aforementioned book edited by the Television Society.

In the present invention, the brightness of each pixel of a display object, that is,
The quantity t given by equation (1) is stored in the frame memory corresponding to the display density of the display device, and the color difference signal, that is, 2〇)
and the quantity given by equation (3) is stored in the frame memory in terms of brightness and rough density. The information in the frame memory can be processed by equations (4) to (6) and sent to a display device such as a CR or T to display the object. in this case,
The frame memory for storing color difference signals can have a smaller capacity than that for luminance.

[Embodiments of the invention]

An embodiment of the present invention will be briefly described below with reference to FIG. A host computer 1 manages the graphic database 2, issues display commands to the graphic display processor 13, and sends graphic information stored in the graphic database 2. The figure database consists of information on numerical values and symbols that represent figures mathematically. The graphic display processor 13 uses the geometrical information of the graphic from the host computer 1 to
Display the figure on the screen of T9.

The display processor t13 consists of a graphic processor 3, an input matrix circuit 4, a luminance frame buffer 5, a color frame buffer 6, a color frame buffer 7, and an output matrix circuit. Coordinate transformation for graphical information such as the coordinates of the vertices of the polyhedron, clipping to cut out the part of the display object to be actually displayed, and strong RED, Ea of RGB of each pixel of CET9.

Based on Ex, Be, and Em from the graphics processor 3, the input matrix circuit 4 uses equations (1), (2), and (3) to calculate the E!, B
@ and El are calculated, and Eyf: is stored in the corresponding location of the luminance frame buffer 5, which has a storage location corresponding to each pixel of CET9, and Et and EQ are stored in the chrominance frame buffer 6, which will be described later.
and 7 respectively. As mentioned before, the luminance frame buffer 5 corresponds to the pixel of %C几T9.
Remember y. Ey is stored as 8-bit information.

The color difference frame buffers 6 and 7 divide the CET screen into vertically and horizontally defined pixels, for example every 2 pixels, and divide the screen into divided rectangles (in this example, a 2 pixel x 2 pixel rectangle). Store color difference information. Therefore, it is only necessary to store color difference information of representative points within the divided rectangles in the color difference frame buffer. This writes to the color difference frame buffer when the least significant bits of display addresses X and Y are both VcO, and when reading, sets the least significant bits of display addresses X and Y to 0 and accesses the color difference 7 frame buffer. This can be easily realized by El is 7 pits, EQ is 6
Stored as bit information. Output matrix circuit 8
reads out ET, El, and BQ corresponding to the display pixel from the luminance frame buffer 5, chrominance frame buffer 6, and chrominance frame buffer 7, respectively, in synchronization with the scanning information of CET9, and calculates equations (4), 1, and 5. Formula (6) t-
is used to obtain the RGB intensity and send it to CET9. CRT9
Now display the entire figure on the screen. At this time, human vision has a lower perceptual ability for color changes than for brightness changes, so bit a of the color difference information on the color difference frame buffers 76 and 7 is set to be less than that of the brightness information. can do. Also, in the color difference information, if El has a higher perceptual ability for changes, it can be made smaller than that of the bit number t-Er of the color difference information on the color difference frame buffer for EQ. Also, Ey, Et
, since the discrimination ability of EQ is non-linear, by performing non-linear quantization that performs coarse quantization in areas with low discrimination ability and thin quantization in areas with high discrimination ability, the efficiency of frame buffer bit usage can be improved. You can increase it,
The frame buffer capacity can be reduced. Nonlinear quantization can be easily realized using the tables shown in FIGS. 2 and 3.

Since Ey, Et, and EQ calculated by the human matrix circuit are digital values, look up the values in table 10 (2) 17 t- when these are viewed as positive integers. Table 10 has a structure in which entries 101 to 103 are lined up. Entry lO1 is the value after nonlinear quantization when the value is 0, and entry 102 is the nonlinear quantization value when the value is 1. The values after nonlinear quantization are stored, and the values after nonlinear quantization are sequentially changed to EY′ for Ey, as shown in FIG.
is memorized. Therefore, nonlinear quantization can be performed by looking up this table. El and BQ
Similarly, the output matrix circuit calculates the luminance and color difference frame buffer information using Table 11, and the input matrix circuit calculates ftEr, Bt, and E.
Return to Q. Entry IIIK of table 11 stores the value of By, Er, or E when the luminance or color frame buffer value is O, and entry 112 stores the value when the frame buffer value is 1 in sequence. ing.

By using this table, a non-linearly quantized value can be returned to a linearly quantized value.

According to this embodiment, since the pixel generation process is performed locally in the graphic display processor 13, the pixel generation process is performed by the host computer.

In contrast, when sending directly to CET9, the amount of information transferred from the host computer I can be eliminated. Also,
Since pixel generation processing is performed by the graphic processor 13, the load on the host computer can be reduced.

〔Effect of the invention〕

According to the present invention, the capacity of the frame buffer for storing color difference information can be made smaller than the capacity corresponding to the number of pixels of the display device.

[Brief explanation of drawings]

The first factor is a block diagram of the present invention, FIGS. 2 and 3 each show a conversion table for nonlinear quantization, and FIG. 4 shows values stored in the conversion table of FIGS. 2.3. It's Guji 7. DESCRIPTION OF SYMBOLS 1... Host computer, 2... Graphic f-1 pace, 3... Graphics processor, 4... Input matrix circuit, 5... Brightness frame buffer, 6
...Color difference frame buffer, 7...Color difference frame buffer, Figure 2 Figure 3 Room 4 entry/exit direct

Claims (1)

[Claims] 1. In a device that calculates and displays the color and brightness of each pixel on a display device from information on the form and arrangement of display figures, each RGB intensity is converted into brightness information and color information. a first frame buffer for storing the converted luminance information; a second frame buffer for storing the converted color information; and a luminance stored in the first and second frame buffers. A graphic display device comprising a device for converting information and color information into RGB intensities. 2. The second frame buffer stores the color information of one pixel for a plurality of pixels as a representative color information of the plurality of pixels. Graphic display device. 3. The number of bits of the color information stored in the second frame buffer is smaller than the number of bits of the luminance information stored in the first frame buffer. graphical display device. 4. The graphic display device according to claim 1, wherein the color information is subjected to non-linear quantization and stored in the second frame buffer. 5. The graphic display device according to claim 1, wherein the luminance information is subjected to nonlinear quantization and is stored in the first frame buffer. 6. Information on the form and arrangement of display figures is given by the host processor, and lower processors including the luminance frame buffer and the color frame buffer calculate the color and brightness of pixels on the display device. A graphic display device according to claim 1 characterized by: