JPS6215988A - Transmission equipment for still picture - Google Patents

Abstract

PURPOSE:To optionally select a still picture requested by a reception equipment judging from the relation between a transmission speed and picture quality by varying a data compression step by a process part and exchanging information between a transmission equipment and the reception equipment. CONSTITUTION:At a process part 7, a data compression process is performed on the data of an image memory 4 according to the information of the data compression step transmitted from the process part 13 of a reception equipment 2 through a modem 9, a telephone line 15 and a modem 6, and it is stored at a compression memory 5. And a packet is generated with adding compression step information on the compression data of the compression memory 5 and the compression data is transmitted within the receiver 2 through the modem 6, the telephone line 15 and the modem 9. The process part 13 of the receiver 2 stores the compression data temporarily at an expansion memory 10 and stores the compression data at an image memory 11 by expanding it inversely to an original picture data according to the compression stop information. The picture data stored at the image memory 11 is changed to an analog signal at a D/A converter 12 and is imaged on a monitor 14 as the still picture.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a still image transmission device that can transmit still images over a telephone line.

2. Description of the Related Art A conventional still image transmission system is shown in FIG. 2, where 21 is a transmitting device and 22 is a receiving device. One frame of the image captured by the television camera 27 is converted into a digital signal by the A/D converter 23 in the sending bag @ 21 and stored in the image memory 24. The image data stored in the image memory 24 is transmitted to the encoding circuit 25 at a low transmission speed, and data is compressed by an encoder such as [)PCM. The compressed data is sent to the telephone line [133] through the modulator 26. The transmitted data is demodulated by the demodulator 28 of the receiving bag @22,
The data is decompressed by the decoding circuit 29 at low speed and stored in the image memory 3.
Stored at 0.

The image data stored in the image memory 30 is transferred to D/A at high speed.
The signal is converted into an analog signal by a converter 31 and displayed as a still image on a monitor 32.

Problems to be Solved by the Invention However, in a still image transmission system having such a configuration, since the encoding circuit is fixed, the data compression accuracy is also almost fixed. The video signal band is approximately 4 MHz, and the bandwidth 4
Transmitting this over a KHz telephone line requires about 1000 times more time axis conversion, so conventional methods have been used to compress the data using an encoding circuit and increase the transmission speed of image data per frame. However, if data compression accuracy is improved, the transmitted image quality generally deteriorates, and the current situation is that transmission speed and image quality are inversely proportional. As mentioned above, since the encoding circuit is fixed, it has been difficult for those who request still images to choose between transmission speed and image quality.

The present invention solves the above-mentioned problems, and aims to provide a still image transmission device that allows a receiving device to freely select a desired still image depending on the relationship between transmission speed and image quality.

Means for Solving the Problems In order to solve the above problems, the present invention provides an image memory that stores video signals converted into digital data by an A/D converter, and a processing section that performs data compression processing on the image memory. a compression memory for accumulating compressed data compressed by the processing unit; a transmitting device for converting the data in the image memory or the compression memory into a packet configuration in the processing unit and transmitting it onto a telephone line by a modulation/demodulation device; It has an expansion memory that stores compressed data obtained by demodulating uniform data transmitted from the device by a modulation/demodulation device, a processing section that expands the data in the expansion memory, and an image memory that stores the data expanded by the processing section. , and a receiving device that reproduces the data in the image memory into a video signal using a D/A converter.

Effect: With this configuration, the processing section of the transmitting device compresses image data using software technology according to the data compression accuracy requested by the receiving device, and the processing section of the receiving device prioritizes either transmission speed or image quality. If the image quality initially requested on the receiving side is not clear, it is possible to transmit a clearer image quality again by further lowering the compression level on the transmitting side, and the receiving side can transmit information on the compression level. By referring to it, it can be signaled as image data using software technology.

EXAMPLE An example of the present invention will be described below based on the drawings. 1st
The figure shows a block diagram of an embodiment of the present invention, where 1 is a transmitting device and 2 is a receiving device. The image captured by the television camera 8 is converted into a digital signal by the A/D converter 3 in the transmitting device 1 and stored in the image memory 4. ! I[In section 7, the receiving device! The data in the image memory 4 is subjected to data compression processing in accordance with the data compression stage information transmitted from the processing unit 13 of the image memory 2 through the modulation/demodulation unit W19, the telephone line 15, and the modulation/demodulation device 6, and is stored in the compression memory 5. . Then, compression stage information is added to the compressed data in the compression memory 5 to generate a packet, and this compressed data is passed through the modem 6, the telephone line 15, and the modem W19 to the receiver W12.
Send within. The processing unit 13 of the receiving device f2 temporarily stores the compressed data in the decompression memory 10, and conversely decompresses the compressed data into the original image data according to the compression stage information and stores it in the image memory 11. The image data stored in the image memory 11 is converted into an analog signal at high speed by a D/A converter 12 and displayed on a monitor 14 as a still image.

If you want to see a still image displayed on the monitor and see a clearer image, the processing section 13 sends the processing section 7 of the transmitting device 1 via the modem 9, telephone line 15, and modem 16 to the compression stage mode again. Send selected request signals. The processing unit 7 compresses the data in the image memory 4 according to the request, or transmits the data in the image memory to the receiving device 2 without compression in the same manner as described above.

Effects of the Invention As described above, in the present invention, the processing unit can change the data compression stage, and by exchanging information between the transmitting device and the receiving device, the transmitting device can compress data at the data compression stage requested by the receiving device. The transmitter and receiver can freely select the image quality and transmission speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a still image transmission apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional still image transmission apparatus. 1... Transmitting device, 2... Receiving device, 3... A/D
Converter, 4... Image memory, 5... Compression memory, 6
...Modulation/demodulation device, 7...Processing unit, 8...Video camera, 9...Modulation/demodulation device, 10...Expansion memory, 1
1... Image memory, 12... D/A converter, 73.
...Processing unit, 14...Monitor, 15...Telephone line.

Claims (1)

[Claims] 1. An image memory that stores video signals converted into digital data by an A/D converter, a processing unit that performs data compression processing on the image memory, and a compression unit that stores the compressed data compressed by the processing unit. a transmitting device having a memory, in which data in the image memory or the compression memory is configured into a packet in the processing section and transmitted onto a telephone line by a modem, and a modem that transmits the image data transmitted from the transmitting device; has an expansion memory for storing compressed data demodulated by a processor, a processing section for decompressing the data in the expansion memory, and an image memory for storing the data expanded by the processing section, and the data in the image memory is subjected to D/A conversion. A still image transmission device equipped with a receiving device that regenerates video signals using a receiver. 2. The transmitting device receives the data compression stage information selected by the receiving device through its modulation/demodulation device, and uses its processing unit to transmit the image data as is, or changes the compression stage to provide high-speed, low-quality or low-speed data on the receiving device side. 2. The still image transmission device according to claim 1, wherein processing is changed to satisfy a requirement for high image quality.