JPS6143713B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display device that displays grayscale graphics.

Conventionally, when displaying grayscale figures, random scan display devices display the end points of line segments as bright spots, and display the grayscale figures by changing the density of these bright spots. In addition, raster scan type display devices employ a method of displaying by density distribution in which special characters and special symbols are combined, similar to the creation of grayscale figures in line printers. Furthermore, for color display devices, a method has been proposed in which three primary color information is used as luminance information to display shading figures.

The method used in the former raster scan system requires about 3 to 5 microseconds to position one bright spot, so if the screen refresh time is 25 milliseconds, the entire screen will need 8300 to 5000 spots. Only very low-density figures consisting of bright spots can be displayed. In other words, the number of grids on the entire screen is 1024×
1024, the number of grid points that can be used for graphic display is only 0.5% to 0.8%, which is not suitable for displaying gray scale figures. Although the problem of the number of grid points can be improved by using a storage tube, it takes several minutes to several tens of minutes to create a screen, which is not practical.

The latter method, which uses a combination of characters and symbols, cannot display detailed shading figures and is not suitable for image processing purposes. Furthermore, the method considered for color display devices requires 5 bits of information per bright spot when the brightness level is set to 32 levels, for example, and requires a huge amount of storage capacity to store information for one screen. Buffer memory will be required.

SUMMARY OF THE INVENTION An object of the present invention is to provide a grayscale graphic display device that solves the above-mentioned problems.

That is, the display device according to the present invention employs a raster scan method, and the central processing unit receives section information indicating the same brightness level section in the raster scan direction and brightness level information indicating the brightness level in the same brightness level section. It is stored in a buffer memory for screen refresh, and by sequentially reading this buffer memory, a luminance signal corresponding to the luminance level information corresponding to the section specified by the section information is supplied to the display section to display a grayscale figure. In a preferred embodiment of the present invention, the brightness level information is given as a relative level (brightness change position) with respect to the brightness level of the zone immediately preceding the corresponding zone.

In this way, according to the present invention, the area of the same brightness level and its brightness level are specified instead of dot units, so the buffer memory for screen refresh does not require a very large capacity, and by specifying the area finely, it is possible to Shaded shapes can also be displayed,
Moreover, the screen creation time can be made equivalent to that for displaying constant brightness level figures on a general raster scan type display device, and high-speed display is possible.

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

FIGS. 1a and 1b show an example of a shading pattern and the luminance distribution in rasters A and B in FIG. 1 for explaining the principle of the display device of the present invention.
In FIG. 1a, the brightness level is highest at the center of the same center, and the brightness level gradually decreases in the surrounding areas. FIG. 1b shows the luminance portions on raster A and raster B in the same figure, and here they are expressed in five luminance levels from 0 to 4.
In other words, the sections a to b, g+1 to h on raster A
(All are dot timing conversions. The same applies hereafter.) Luminance level 1, sections b+1~c, f+1~
g is the brightness level 2, and similarly, the sections d+1 to e are the highest brightness level 4. Raster B can be considered in the same way. The brightness levels described above may be divided into arbitrary stages as necessary, and the more finely the stages are divided, the more detailed the shaded figure can be expressed.

In the display device of the present invention, when displaying the figure shown in FIG.
+1~e, e+1~f, f+1~g, g+1~h
(However, in the case of Rask A) section information (Δ
X) and brightness level information (ΔY) indicating the absolute value of the brightness level in each section or the relative value with respect to the immediately preceding period are received from the central processing unit and stored in a screen refresh buffer memory. and,
Section information and luminance level information are sequentially read out from the buffer memory, a luminance signal is created for each section, and the luminance signal is supplied to the display section to display a predetermined gradation figure.

FIG. 2 shows a preferred embodiment of the display device according to the present invention, and will be described in detail. In this example,
The number of bits of the brightness level information, in other words, the capacity of the screen refresh buffer memory, is reduced as much as possible by receiving the relative value of the brightness level with respect to the previous section as brightness level information (ΔY) from the central processing unit. It is.

In FIG. 2, reference numeral 1 denotes a buffer memory for refreshing the screen, and this buffer memory 1 stores section information (.DELTA.X) and brightness level information (.DELTA.Y) from the aforementioned central processing unit. Section information (.DELTA.X) and brightness level information (.DELTA.Y) read from buffer memory 1 in synchronization with the raster scan of the screen are set in .DELTA.X register 3 and .DELTA.Y register 2, respectively. The contents of the ΔY register 2 and the contents of the brightness level 7 are added by an adder 4. On the other hand, the ΔX register 3 is counted down at the dot timing in the raster direction, and at the end of the interval immediately before the interval indicated by the interval information (ΔX) set in the ΔX register 2, that is, the interval corresponding to the contents of the ΔY register 2. Timing T is output from the decoder 5. At this timing T, the AND gate 6 is opened and the output of the adder 4 is set in the brightness register 7. As described above, in this example, the brightness level information (ΔY) of each section is given as a relative brightness level with respect to the immediately preceding section. Therefore, the contents of the brightness register 7 indicate the absolute brightness level of each section. A digital/analog converter 8 converts the absolute brightness level information in the brightness register 7 into an analog value and outputs it as a brightness signal.
Send to CRT display section 9.

Here, the operation for the sweep period of raster A when displaying the gray scale figure shown in FIG. 1a will be explained. Before the beam reaches point a, the brightness register 7
The content of is “0”. When the beam reaches point a, timing T is output from the decoder 5, and the output of the adder 4, that is, the contents of the ΔY register 2 in this case, is set in the brightness register 7 as is. At this point, the contents of ΔY register 2 are in the interval (a+
Since the relative brightness level "1" for the previous section (0-a) of 1-b) is set, the contents of the brightness register 7 will indicate the absolute brightness level "1". Almost simultaneously with the occurrence of the timing T, section information (ΔX) indicating the section (a+1 to b) is set in the ΔX register 3, and the next section (b+1 to b) is set in the ΔX register 3.
Luminance level information (ΔY) indicating the relative luminance level “1” of d) is set in the ΔY register 2.

When the beam reaches point b, the decoder 5 outputs a timing T, and the adder 4 adds the contents of the registers 2 and 7 and sets the result in the brightness register 7. In other words, the absolute brightness level of the interval (b+1 to c) obtained by adding the content "1" of the brightness register 7 and the content "1" of the ΔY register 2 is "2".
is set in the brightness register 7.

Thereafter, in the same manner, information indicating the absolute brightness level as shown in FIG. 1b is created in the brightness register 7, and thus a gray scale figure as shown in FIG. 1a is displayed.

The display device of the present invention has the above-described configuration, and can display detailed shading figures at high speed based on section information and brightness level information.Also, since the brightness level is specified for each section of the same brightness level, screen refresh is possible. The capacity of buffer memory can be reduced as much as possible.

[Brief explanation of the drawing]

Figure 1a shows an example of a shading pattern, Figure 1b
1A is a diagram showing the luminance distribution on raster A in FIG. 1... Buffer memory, 2... ΔY register,
3...ΔX register, 4...Adder, 5...Decoder, 7...Brightness level, 8...Digital/analog converter, 9...CRT display section.

Claims (1)

[Claims] 1 In a raster scan type display device, section information indicating the same brightness level section in the raster scan direction and brightness level information indicating the relative level to the brightness level of the section immediately before the same brightness level section are stored. a first refresh memory that sequentially reads the interval information and brightness level information stored in the refresh memory and generates timing information at the end of the same brightness level interval specified by the read interval information; and a brightness register that holds an added value of the brightness level information, adds the brightness level information and the contents of the brightness register, and calculates the addition result according to the timing information generated by the first means. A display device comprising: second means for holding a luminance signal in the luminance register; and third means for creating a luminance signal based on the contents of the luminance register and supplying the generated luminance signal to a display section.