JP2778274B2 - Still image transmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for transmitting an image, and more particularly to a system for transmitting a quantized still image.

[0002]

2. Description of the Related Art Conventionally, in this type of still image transmission system,
The image represented by the television signal is encoded and transmitted as image data, and a control code indicating one frame of the image data is inserted into the image data for one horizontal scanning period. On the receiving side, a method of detecting this control code from the decoded image data, knowing the break of the image data for one horizontal scanning period based on the control code, and arranging the image data to reproduce the received image. Has been taken.

[0003]

When image transmission is performed by such a conventional method, if a transmission error occurs on a communication line and a control code for each horizontal scanning period cannot be detected on the receiving side, the image is transmitted. A data break cannot be detected, and thereafter the image is received in a state where the vertical direction is shifted to the end of the image data, and there is a problem that the image cannot be reproduced accurately. An object of the present invention is to provide a still image transmission system capable of obtaining a reproduced image which is less affected by a transmission error.

[0004]

According to the still image transmission method of the present invention, a transmitting unit for encoding and transmitting an image represented by a television signal is provided in a vertical direction every one horizontal scanning period of image data to be transmitted. A means for transmitting address data,
The receiving unit that decodes the transmitted signal and reproduces an image has means for detecting vertical address data from the received data, and sets a screen display position in one horizontal scanning period of the image data based on the detected vertical address data. Means to perform.

[0005]

According to the present invention, since the receiving section performs image reproduction by arranging image data based on the vertical address data, the transmission error only affects that part of the image and affects the entire image. There is no.

[0006]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a still image transmission system according to the present invention. In FIG. 1, reference numeral 1 denotes a transmitting unit, and 2 denotes a receiving unit.
And the receiving unit 2 obtains a reproduced image. The transmitting unit 1 includes an analog-digital converter 1
1, memory 12, selector 13, encoder 14, modulator 1
5, an address generator 16, a control data generator 17, and a controller 18. The receiving unit 2 includes a demodulator 21, an encoder 22, a memory 23, a digital-analog converter 24, a control data detector 25, and address generators 26 and 2.
7 is comprised.

In the transmitting section 1, the input video signal 10
1 is converted into digital data 102 by the analog-digital converter 11 and written into the memory 12.
At this time, the write address to the memory 12 is indicated by address signals 103 and 104 generated by the address generator 16. Here, 103 is a horizontal address and 104 is a vertical address. The address generator 16 includes the control unit 1
8 generates a write address to the memory 12 and a read address when transmitting an image. At the time of image transmission, the image data written in the memory 12 is read from the address indicated by the address signals 103 and 104, passes through the selector 13 as transmission data 106, is encoded by the encoder 14, and is transmitted by the modulator 15. The modulated signal is transmitted to the line 20. When the image data is transmitted for one horizontal scanning period, the control data generator 17 outputs a signal 108 obtained by adding the vertical (vertical) address 104 of the image data to the image data delimiter code according to the control signal 107 from the control unit 18. Output. The signal 108 is selected in the selector 13 by the control signal 109 from the control unit 18, and is transmitted to the line 20 through the encoder 14 and the modulator 15. FIG. 2 shows the format of the signal transmitted to the line 20.

[0008] In the receiving section 2, the signal from the line 20 is demodulated by the demodulator 21 and the signal 20
1 is input to the memory 23 and the control data detector 25.
In the memory 23, the data is written to the address indicated by the addresses 202 and 203 generated by the address generator 26. Here, 202 is a vertical address, and 203 is a horizontal address. In the control data detector 25, the signal 201
, And a vertical address subsequent thereto are detected, and the generated address 202 is set to the detected vertical address by the signal 204 to the address generator 26, and the generated address 203 is set to the horizontal start address. . The image data written in the memory 23 is composed of the reproduced image data 2 from the address indicated by the vertical address 205 and the horizontal address 206 generated by the address generator 27.
07 and read from the digital-analog converter 2
The signal is converted into an analog signal at 4 and output as an output video signal 208.

Therefore, in this still image transmission device,
Even if the delimiter code or vertical address inserted into the image data cannot be detected due to an error on the transmission line,
If the vertical address can be detected thereafter, the received data will be written to a normal position in the memory at that time. Therefore, one undetection of the delimiter code due to an error on the transmission line is one horizontal line for the received image. The influence of the scanning feedback can be contained, and the image can be reproduced almost accurately.

[0010]

As described above, according to the present invention, the transmitting unit transmits the vertical address data for each image data in one horizontal scanning period, and the receiving unit detects the vertical address data from the received data, and Since the image data is set at the screen display position indicated by the address data, even if the receiving unit cannot detect the vertical address data due to an error in the transmission line, the vertical address data detected thereafter may be used. The received data can be written to a normal position on the memory, and the effect of errors on the transmission line on the image can be reduced, and there is an effect that substantially accurate image reproduction can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a still image transmission system according to the present invention.

FIG. 2 is a configuration diagram of a signal of the present invention transmitted on a line.

[Description of Code] 1 Transmitting Unit 2 Receiving Unit 12 Memory 13 Selector 14 Encoder 15 Modulator 16 Address Generator 17 Control Data Generator 18 Control Unit 20 Line 21 Demodulator 22 Decoder 23 Memory 25 Control Data Detection 26, 27 Address generator

Claims (1)

(57) [Claims] 1. A still image transmission system comprising: a transmission unit that encodes and transmits an image represented by a television signal; and a reception unit that decodes the transmitted signal and reproduces the image. Includes means for transmitting vertical address data for each horizontal scanning period of image data to be transmitted, and the receiving section includes means for detecting vertical address data from the received data, and means for detecting the vertical address data based on the detected vertical address data. Means for setting a screen display position during one horizontal scanning period of image data.