JPH03234173A - Color picture data generating system and displaying system - Google Patents

Abstract

PURPOSE:To display a visually natural and easy to see picture by sampling different color component sequentially with these A/D converters and a data selector and using the result as a picture element data. CONSTITUTION:R, G, B analog output signals such as an output of a TV camera are A/D-converted into digital signals and a data selector is used sequentially to select any of the R, G, B data repetitively and to obtain the picture data. The signal inputted to a display device is selected not to be the R, G, B primary color signal but to be a signal displaying a color being a mixture of adjacent picture elements. Thus, the color of each picture element is recognized to avoid it that the original picture color is not observed and the color of the original picture is almost accurately reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of compressing image data used for recording and transmitting color images, and a method of displaying images using the compressed data.

[Conventional technology]

Currently, when transmitting images in computer communications, etc., a method is used in which the signal from a television camera or other image input device is converted into digital data, and this data is transmitted via a telephone line using a modem. In order to compress (increase speed) the modem, image compression methods have been devised and used in which the image data is processed by a computer or the like to reduce the data capacity.

The current data compression method using digital data requires accurate data without errors in order to restore the compressed data to the original data, so this compressed data is transmitted via a telephone line using a modem. When transmitting data, errors that occur during transmission become a problem, and modems with high transmission speeds have a high probability of errors occurring, and the modems themselves are expensive. Usually the modem is “
It is considered to perform serial data transmission of binary data of "1" or "φ", and a sequence of several bits is treated as one data. There is a modem circuit suitable for transmitting analog data such as that used in telephones, and this type of circuit has a simple circuit configuration, making it a low-cost modem, and the transmission speed is similar to that used on general telephone lines. As a data modem, it is easy to obtain a transmission speed equivalent to or higher than the 9600 bps belonging to a high-speed modem, but with this type of modem, the accuracy is around 4 bits to 8 bits). Since it was designed to transmit the corresponding data, the corresponding transmission speed is expressed by converting the analog value to a digital value, so although it is numerically faster, basically the transmission speed is Since this is not a method for transmitting bit data, even if compressed data created by the digital data compression method used in computer communications, etc., is transmitted, the original data cannot be restored. However, since the circuit is much simpler and cheaper than a normal data modem with the same transmission speed, there are image data compression methods that can be used with this method and their data restoration. If there is a (image display) method, it will be possible to realize a low-cost, high-speed image transmission device.

Therefore, in the present invention, we have devised an image data compression method and a restoration (image display) method that are less susceptible to errors during image data transmission and can be used even with modems with low data accuracy such as those described above. This is used to create (compress) data that includes human visual characteristics at the time the image is displayed, in color image transmission, where speeding up is often desired among image transmission methods.
The aim is to achieve the best color image display with the minimum amount of image data by performing this process, and since the compressed data does not include any encoded data unlike normal digital data compression, data restoration (image The effect of data accuracy on display) is very small.

The present invention will be explained in detail below.

In a normal image data creation method, an image (plane) is decomposed into pixels (dots) and converted into data by sampling the image signal output from a television camera, scanner, etc. at regular intervals.

For example, first considering a black and white image, when converting one screen into data with 14 dots horizontally and 9 dots vertically, the image becomes as shown in Figure 1, and each pixel P1 to P126 samples the luminance component at that position. This data has been converted into data.

When creating data as a color image, the three primary colors (red, green, blue) at the same position are used instead of the luminance components of each pixel.
It is only necessary to sample the components at each pixel position and convert them into data. According to this method, color image data has three times the data capacity compared to black and white image data, but the color image data creation method according to the present invention Then, R(
RSG, B (red) component, G (green) component, and B (blue) component are not converted into data for each pixel (position).
Only one of the color components is converted into data and used as color image data. For example, in Figure 1, Pl is the R component,
When converted into data such as P2 as a G component, P3 as a B component, and P4 as an R component, data of different color components are lined up as shown in FIG.

In this example, it is explained that Pl is the R component, but it can be from the G component or the B component, and it is not necessary that the same color data is always lined up in the vertical direction, but the R,
By repeating G, B, R, G, B, etc. in the same order, it is possible to obtain data with uniform color reproducibility at any position. Furthermore, in the pixel arrangement shown in Figure 2, at any position among the pixels lined up in the horizontal direction, 3
If one pixel (data) is extracted, it always contains one each of R, G, and B, so uniformity is maintained in the horizontal direction, but it is necessary to maintain uniformity in the vertical or diagonal directions as well. You can also do it. This is illustrated in Section 3-1.
It is a diagram. If we create data with the arrangement of color components R, G, and H shown in the figure at the pixel positions shown in this figure, for example, if we use R23 as a reference, we will create 3 pixels in the horizontal direction centered on R23. Pixel (B20.R23, G21)
Of course, even if we consider three pixels adjacent to each other including R23 (R23°G16.B20), (R23, G21.
B16) (R23, G25.B20), (R23, G
21°B25), and in the diagonal direction (B 16°R23, G25), (G16.R23, B25), all of which contain one each of R, G, and B. This is maintained even on a pixel basis, and the uniformity of the color image data is better than that of FIG. 2.

In FIG. 3-1, the upper left pixel in the figure is shown as R component data, but other color components G and B may be used.

Examples of hardware configurations for actually creating the above data are shown in FIGS. 4-1 and 4-2. No. 4-1
The figure shows R and G outputs from a TV camera, etc.

B: A method of converting an analog output signal from analog to digital (hereinafter referred to as A-D conversion) by repeatedly selecting one of R, G, and B data using a data selector after converting it to digital.

Figure 4-2 shows a method in which only one of R9G and B is selected using a switch capable of high-speed operation such as an analog switch at the time of an analog signal, and this is converted from A to D to become data. . By writing this output data into a frame memory, color image data can be stored in the same memory capacity as monochrome images.

This example explains how to create color image data in real time from the output of a TV camera, etc. and import it into frame memory.
From the color image data captured as 3 frames, R, G.

B By repeatedly reading the data one by one from each frame, the same data as the color image data according to the present invention can be obtained.

Next, a method for displaying color image data on a display device such as a cathode ray tube according to the present invention will be explained.

When displaying color image data according to the present invention, the compressed data can be directly displayed depending on conditions such as the size of the display device, the number of pixels constituting one screen, and the distance between the display device and the human eye viewing it. Color (R.

G, B), the interval between the color points of each pixel is less than the color separation ability of human vision, that is, R, G
, H cannot be recognized as a point and appears as a mixed color, and in other cases the color of each pixel can be recognized and therefore the color does not appear as the original image.

In order to prevent this, the present invention solves this problem by changing the signal input to the display device from the beginning to a signal that displays the color when the colors of adjacent pixels are mixed, rather than as the primary colors of R, G, and B. are doing. Since this mixed color is determined by the pixels of the three primary colors that are adjacent to each other in the horizontal, vertical, and diagonal directions on the display, the colors of the original image can be reproduced very accurately.

Specific examples of this are shown in Figures 5-1 and 5-2.
FIG. 5-3. In these methods, three pieces of color data adjacent to each other in the horizontal direction are used and mixed. As explained earlier, whenever three pieces of data are extracted in the horizontal direction, one each of R, G, and B data is included, so the color reproducibility is extremely high.

In this example, only the horizontal direction is processed and displayed, but since the vertical correlation between the lines of the image is very high in boat fishing, even if only this processing is performed, it is not possible to display a natural image. I can do it. Of course, a more natural display can be achieved by performing more advanced processing, such as processing including pixels in the vertical and diagonal directions, or by combining various interpolation processes.

To explain the operations shown in Figures 5-1, 5-2, and 5-3, compressed image data based on the color image creation method according to the present invention is input to the n-bit digital input in each figure. This data is written in a frame memory, and is displayed on a display device such as an RGB monitor or a television. If the data in the frame memory is read out using an appropriate read clock, R, G, B, R, G, B, etc. data will be read out in synchronization with the clock. 5-2 shows the digital data, and FIG. 5-3 shows the analog signal, which holds the data until the next data of the same color is entered manually.

Figure 5-1 shows the clock signal with the timing shown in Figure 6.
When added to the latch circuit and D-A converter circuit in Figure 5-2, each analog output of R, G, and B outputs a signal obtained by performing D → A conversion when data of that color is input, The operation of holding that output until the next data of the same color is input is repeated. By doing this, R,G
, H is manually input to a display device with RGB input, the RGB display overlaps and is displayed as a mixed color on the screen of the display device as shown in FIG.

Also, when displaying an image on a TV, the RGB analog signal outputs can be converted to a composite color signal and input to the TV's video signal input, or this signal can be modulated and connected to the TV's antenna input. . When converting to a composite signal and displaying it, the colors displayed on the screen are not mixed on the display screen, but
Although the colors mixed in the RGB→composite color signal conversion circuit are displayed, it is natural that the displayed images will have the same color. A feature of this display method (image data restoration) is that the number of input data and the number of displayed pixels are the same even though a color image is displayed. Other methods, such as normal one pixel R
, G, and B components into 3-frame memory, the data capacity is 1/3 of that of this method for the same data capacity.
The number of pixels becomes , and the luminance signal Y, (RY)
.

Even with a method that captures Y, (B-Y), Y, (R-Y) data as image data, the number of pixels is 1/2 that of this method if the data capacity is the same. It is clear that the display screen using this method can display images that are more visually natural and easier to view.

As explained above, by using the image data creation method and display method according to the present invention, color images can be stored and transmitted using the same data capacity as black and white images, so efficient recording is possible. Therefore, in terms of transmission, color images can be transmitted by transmitting the same capacity as black and white images, and since the data is not encoded compressed data, it is extremely unlikely to be affected by errors during transmission. Not only can it be used to shorten the color image transmission time of various image transmission devices using data modems that send ordinary 1"φ data, but it can also be used to reduce the time required to transmit color images, such as those used in still image videophones, which contain considerable errors during transmission. Since it can also be used for transmission methods that are considered to be similar, it becomes possible to realize a device that can perform high-speed color image transmission at low cost.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the arrangement of pixels (data) by a normal image capturing method and the image data creation method according to the present invention. FIG. 2 is a diagram showing an arrangement of pixels (data) according to the image data creation method according to the present invention. FIG. 3-1 is a diagram showing an arrangement of pixels (data) devised to improve visual image quality in the image data creation method according to the present invention. FIG. 3-2 is a diagram showing pixels when the image data of FIG. 3-1 is displayed on a display. 4-1 and 4-2 are diagrams showing an example of a circuit for creating color image data according to the present invention. 5-1, 5-2, and 5-3 are diagrams showing examples of circuits for displaying color image data according to the present invention. FIG. 6 is a diagram showing the operation timing of FIGS. 5-1, 5-2, and 5-3. FIG. 7 is a diagram showing a pixel arrangement when an image is displayed on a display using the color image display method according to the present invention.

Claims (1)

[Claims] 1. A method for creating color image data and a method for displaying the same, characterized in that when converting a color image into data, different color components are sequentially sampled and this is used as pixel data. 2. A color image data creation method and its display method as set forth in claim 1, wherein the color component is any one of red, green, and blue color components within one pixel. 3. Claims 1 and 2 are characterized in that color image data is created and displayed with uniform color information on the screen by arranging pixels differently. Color image data creation method and display method.