JPS63234789A - Still picture television telephone system using microcomputer - Google Patents

Abstract

PURPOSE:To attain a device of low cost and a general purpose by selecting the scale of the quantity of still picture data, and selecting a communication transmission time and a picture quality thereby. CONSTITUTION:A picture signal from a television camera 1 is written in a field memory 23 as a still picture through an A/D converter 21. At the time of designating whether the quantity of the picture data constituting one picture is fine, medium, or rough according to the key operation of a keyboard 5, it is inputted to a CPU 31 via the I/O port 34 of a microcomputer 3. The CPU 31 recognizes it to feed a command to a sampling dot number setting circuit 22 via a data bus DB, the I/O port 34 and the I/O interface 24 of a picture input unit 2. The circuit 22 selects one of plural sampling dots according to this command and stores in the memory 23 via the A/D converter 21. The picture data is transferred to a V-RAM 33 through the I/O port 34 from the memory 23 and displayed on a CRT display 4 according to a transfer instruction from a ROM in a memory 32.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a still image videophone system using a microcomputer.

[Prior Art] Videophones that transmit and receive still images along with audio have been considered. In this still image videophone, the image data is much larger than the text information and audio signals.If one TV screen is a color image of, for example, 400 dots in height x 640 dots in width, the digital signal is 76,800 bits ( -400X640X3). If this digital signal is transmitted as it is over a telephone line with a narrow frequency band, it will take several tens of seconds to several minutes, which is not practical. Therefore, a method is required that compresses the band of the image signal, transmits it, and expands it so that the receiving side receives the original signal. The following methods are usually adopted. That is, after decomposing the image signal and compressing the signal band by the image signal band compression device (CODEC) provided on the receiving side, the maximum transmission speed of the telephone line, 9600 [
bits per second]. On the receiving side, the received signal is reassembled by an image signal band expansion device (CODEC) and displayed on a display section as an original image signal.

[Problems to be solved by the invention] However, the signal band compression/expansion device C0DEC used in still image videophones as described above is a complicated dedicated electronic device and is extremely expensive. This is hindering the spread of videophones.

The present invention has been made in view of the above-mentioned circumstances, and in order to realize a still image videophone using an inexpensive device, a widely used microcomputer is used as a videophone terminal, and an inexpensive general-purpose device is used. The purpose of this invention is to provide a still image videophone system using a flexible microcomputer.

[Means and effects for solving the problems] The present invention uses a microcomputer as a videophone terminal, and transmits image data by selecting the number of sampling dots for image data from among a plurality of settings. Select the size of the signal amount to obtain a still image with dense pixels although the transmission time is long, or to obtain a still image with coarse pixels but with a shorter transmission time.
It is possible to select whether to obtain a short still image as necessary.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of one set of circuits.

In the figure, 1 is a television camera that takes still images, 2 is an image controller that manually processes still image data from the television camera 1, and 3 is a microcomputer body that controls the transmission and reception of image data. ''), 4 is a CRT display device connected to the microcomputer main body 3 and displays sent still images; 5 is a keyboard also connected to the microcomputer main body 3 for giving various operation instructions; 6 is a keyboard This is a modem telephone connected between the microcomputer body 3 and the telephone line 7.

The image input crab unit 2 has an A/D converter 21. Sampling dot number setting circuit 22, field memory 23 and I1
0 interface 24, and analog value still image data from the television camera 1 is input to the A/D converter 21. The A/D converter 21 samples the input image data according to the number of sampling dots designated by the number of sampling dots setting circuit 22, converts it into digital values, and sequentially sends them to the field memory 23. In the field memory 23, one screen worth of digital image data sent from the A/D converter 21 is written.
10 interface 24. The I10 interface 24 outputs still image data read from the field memory 23 to the microcomputer main body 3, and also sends a command input from the microcomputer main body 3 to the sampling dot number setting circuit 22 to indicate a specific number of sampling dots. The signal is sent to the A/D converter 21.

The microcomputer main body 3 also includes a CPU 31 for controlling operations, a memory section 32 consisting of a RAM for storing normal arithmetic data and a ROM for storing programs, a V-RAM 33 for storing image data, and a V-RAM 33 that is directly connected to the outside. R5-, which is connected to the I10 port 34 that performs output control and the above-mentioned telephone line 7, and performs input and output of image data.
The CPU 31, memory section 32, V-RAM 33, and I10 port 34 are interconnected by an address bus AB and a data bus DB, respectively. I10 port 34 is further R5-23
It is connected to the 2C interface 35 and also to the I10 interface 24 of the image input unit 2, the CRT display device 4, and the keyboard 5.

With the above configuration, A in the image-containing crab knit 2
/D converter 21, sampling dot number setting circuit 22, and the image input program of microcomputer main body 3 work together to convert the amount of still image data for one screen to 320 pixels horizontally.
The dots can be selected from three levels: ``fine'', ``medium'', and ``coarse J'': 200 vertical dots, 160 vertical dots x 100 dots, and 80 vertical dots x 50 dots.

The analog value image signal photographed by the television camera 1 is converted into a digital value by the A/D converter 21 in the image input unit 2 for one field (one screen, 1/60 second). , field memory 2 as still image data
3 is written. At this point, the amount of image data constituting one screen can be determined by key operations on the keyboard 5.
The key operation signal is input from the I10 port 34 of the microcomputer main body 3 to the CPU 31 via the data bus DB, and the CPU 31 recognizes this and issues a command. Output.

This command is sent from the data bus DB to the sampling dot number setting circuit 22 via the I10 port 34 and the I10 interface 24 of the image input unit 2. The sampling dot number setting circuit 22 selects one of the plurality of sampling dot numbers set in advance according to this command, and instructs the A/D converter 21 to select one of the plurality of sampling dot numbers set in advance. When one field of image data converted into digital values by the A/D converter 21 is stored in the field memory 23, the image data is transferred to the field memory 23 by a data transfer command written in the ROM in the memory section 32. The data is read out from the I10 interface 24 and sent to the I10 port 34 of the microcomputer main body 3 in the form of parallel transfer. Thereafter, the image data is stored and set in the V-RAM 33 from the I10 port 34 via the data bus DB, and the image data is stored and set in the V-RAM 33 from the data bus DB to the I10 port 3.
4 to the CRT display device 4 for display. Here, the still image displayed on the CRT display device 4 is checked, and if there is a problem, it is indicated by key operation on the keyboard 5, and after the contents of the V-RAM 33 are temporarily erased, the same operation as above is performed again. have them do it. Then, in response to a transfer command of the communication program written in the ROM of the memory section 32, the CPU 31 transfers the data to the V-RAM 3.
The image data stored in 3 is serially transferred from data bus DB via I10 port 34 and R5-232C interface 35, and is transmitted by modem telephone 6 over telephone line 7 to a desired destination.

Now, although the case of transmission has been described above, when receiving image data transmitted from the other party, the operation is as follows. That is, at the time when the image data is transferred from the telephone line 7, the CPU 31 receives the received image data from the modem telephone 6 via the microcomputer in the form of serial transfer based on the reception command of the communication program in the ROM of the memory section 32. R=, S − in the main body 3
The data is input to the 232C interface 35, stored in the V-RAM 33 via the data bus DB from the I10 port 34, and sent to the CRT display device 4 from the data bus DB via the I10 port 34 for display.

As mentioned above, the A/D converter 2 in the image input crab unit 2
1, the sampling dot number setting circuit 22, and the image input program processing of the microcomputer main body 3 work together to convert the still image data for one screen into 320 dots horizontally x 200 dots vertically, 160 dots x 100 dots,
Same 80 dots x 50 dots and 3 levels, ``Semi''
Select from “Medium” and “Coarse”. This allows selection of communication transmission time and image quality.

For example, if you select and specify "Fine" using the keyboard 5, a color still image 1 of 320 dots horizontally x 200 dots vertically will be displayed.
The data m for the screen is 320 x 200 x 3 (color) - 192,000 bits - 24,000 bytes, and if this is sent at a communication speed of 1200 bpsl, 192,000 ÷ 1200 - 160 (seconds), that is, 2
This requires a transmission time of 40 minutes.

Also, if you select and specify "Medium" with keyboard 5, horizontal 1
The amount of data for one screen of a color still image of 60 dots x 100 dots vertically is 160 x 100 x 3 (color) - 48,000 bits - 6,000 bytes, and if this is sent at a communication speed of 1,200 [bps], it will be 48,000 + 1,200 ~ 40 (seconds), that is, This means that transmission can be performed in 40 seconds.

If "coarse" is selected and specified on the keyboard 5, the amount of data for one screen of a color still image of 80 dots horizontally x 50 dots vertically is 80 x 50 x 3 (color) - 12000 bits - 1500 bytes, which is 1200 [bps]. If the data is sent at a communication speed of 12000÷1200-10 (seconds), that is, the transmission can be performed in just 10 seconds.

In this way, depending on the situation at the time of sending, the
You can select whether to obtain a still image with dense pixels but with a long transmission time, or to obtain a still image with coarse pixels but with a short transmission time.

[Effects of the Invention] As detailed above, according to the present invention, a commonly used microcomputer can be used as a videophone terminal, and the number of sampling dots of image data can be selected from among a plurality of settings. Select the size of the signal amount of the image data to be transmitted, and select whether to obtain a still image with dense pixels with a long transmission time, or a still image with coarse pixels but with a short transmission time, as necessary. As a result, a still image videophone can be realized with an inexpensive and versatile device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the circuit configuration of an embodiment of the present invention. 1...TV camera, 2...crab knit with image, 3
...Microcomputer body, 4.CRT display device, 5.Keyboard, 6.Modem telephone, 7.Telephone line, 21.A/D converter, 2.
2... Sampling dot number setting circuit, 23... Field memory, 24... I10 interface, 3
1...CPU, 32...Memory section, 33...V-
RAM, 34...I10 port, 35...R5-2
32C interface.

Claims (1)

[Scope of Claims] Selection means for selecting one of a plurality of sampling dot numbers of image data set in advance; An A/D converter that performs A/D conversion to create digital still image data, an image memory that stores the still image data created by the A/D converter, and a telephone line that transmits the stored contents of this pixel memory. A still image using a microcomputer, characterized in that the still image is equipped with a transmitting means for transmitting to the other party via a microcomputer, the size of still image data can be selected, and communication transmission time and image quality can thereby be selected. videophone system.