JPH11252547A - Image transmitter, image receiver and image transmission system using them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance transmission efficiency in the case of sending an image by reducing the information quantity. SOLUTION: An image signal from a camera 5 is converted into a digital signal by an A/D converter ADC 2 and compression-coded by a compression coding section 3 with a fixed parameter. Then only a main part of the compressed image data is outputted from the compression coding section 3 and the data are sent to a communication line L by a communication control section 4. The data are received by a communication control section 11 of an image receiver 10, the demodulated compressed image data main part is expanded by an expansion section 12 by referencing a parameter table 15 to which parameters used for compression coding by the compression coding section 3. Then the image data expanded by the expansion section 12 are converted into analog data by a DAC 13 and the analog data are displayed on a monitor 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transmitting apparatus for compressing and encoding an image captured by a camera and transmitting the image, an image receiving apparatus for receiving compressed image data transmitted from the image transmitting apparatus, and The present invention relates to an image transmission system in which an image transmitting device and an image receiving device are connected via a communication line.

[0002]

2. Description of the Related Art There is a system for capturing an image of a remote place with a surveillance camera (hereinafter simply referred to as a camera), compressing and encoding an image signal obtained and transmitting the received image signal, and receiving and displaying it on a monitor. Are known. FIG. 2 shows a schematic configuration thereof.

FIG. 2 is a diagram showing an example of the configuration of a system for transmitting an image captured by a camera via a communication line. In the figure, reference numeral 1 denotes an image transmitting device, and 2 denotes an A / D converter (hereinafter referred to as an AD converter).
C, 3) a compression encoder, 4 a communication controller, 5 a camera, 10 an image receiver, 11 a communication controller, 12
Denotes a decompression unit, 13 denotes a D / A converter (hereinafter, referred to as DAC), 14 denotes a monitor, and L denotes a communication line.

[0004] The image signal from the camera 5 is digitized by the ADC 2 and is compression-encoded by the compression-encoding unit 3. JPEG, M
Although a standardized compression encoding system such as the PEG system can be used, the JPEG system is used here. Then, the compressed and encoded image data is packetized in the communication control unit 4 and transmitted to the image receiving device 10 via the communication line L.

[0005] Upon receiving the packet, the communication control section 11 of the image receiving apparatus 10 demodulates the packet and passes it to the decompression section 12.
The expansion unit 12 expands the image data that has been compression-encoded. The image data expanded by the expansion unit 12 is converted into an analog signal by the DAC 13 and displayed on the monitor 14. Therefore, the observer of the monitor 14 can observe the image captured by the camera 5.

[0006]

By the way, according to the JPEG method, when an image is compression-encoded, data consisting of a header and a compressed image data body as shown in FIG. 3 is generated for each image. I do. Various parameters used for compressing and encoding the image are written in the header, and the data amount is usually about several hundred bytes. Actually, the compressed image data is written in the main part of the compressed image data. The data amount of this part depends on the image size and the content of the image.
Bytes to several tens of kilobytes. As shown in FIG. 3, generation of data having a structure including a header and compressed image data for each image is the same in the MPEG system, and other standardized compression encoding systems are also used. But the same is true.

Accordingly, the data having the structure shown in FIG. 3 is output from the compression encoding unit 3 for each image, and the data is packetized and transmitted in the communication control unit 4.

However, in the above-described image transmission system, the parameters used for compressing an image in the compression encoding unit 3 are usually fixed, so that each time one image is transmitted. Sending a header every time is useless in terms of the image transmission time and the amount of transmitted information,
This is not desirable from the viewpoint of transmission efficiency.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image transmitting apparatus, an image receiving apparatus, and an image transmitting system using the same, which can improve the transmission efficiency by reducing the amount of information to be transmitted. It is.

[0010]

In order to achieve the above object, an image transmitting apparatus according to the present invention is an image transmitting apparatus which compresses an image by a predetermined compression encoding and transmits the image. Do not transmit the parameters used to perform
It is characterized in that only the compressed image data itself is transmitted.

An image receiving apparatus according to the present invention is an image receiving apparatus that receives only compressed image data itself, and stores a table in which parameters used for expanding received compressed image data are registered. It is characterized by having.

Further, according to the image transmission system of the present invention, in the image transmission system in which the image transmission device and the image reception device are connected by a communication line, the image transmission device compresses the image by a predetermined compression encoding and transmits the image. In doing
The parameters used to perform the compression encoding are not transmitted, and only the compressed image data itself is transmitted, and the image receiving device registers the parameters used when decompressing the received compressed image data. Equipped with a table,
The received compressed image data is expanded by referring to the parameters registered in the table.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of an image transmitting apparatus, an image receiving apparatus, and an image transmission system using them according to the present invention. In the figure, reference numeral 15 denotes a parameter table. Note that the same components as those shown in FIG. 2 are denoted by the same reference numerals.

First, the image transmitting apparatus 1 has the same block configuration as the conventional image transmitting apparatus shown in FIG. 2, but differs in the following points. That is, the compression encoding unit 3
Compresses and encodes digitized image data, but all parameters used for compression and encoding are fixed. Then, the compression encoding unit 3 outputs only the compressed image data body to the communication control unit 4. That is, the header part of FIG. 3 is not output, and only the compressed image data body part is output. Then, the data of the compressed image data body is packetized by the communication control unit 4 and transmitted to the communication line L.

Next, the image receiving apparatus 10 is as follows. The image receiving apparatus 10 has a parameter table 1
5, all the parameters used when the image is compressed and encoded by the compression encoding unit 3 of the image transmitting apparatus 1 are written in the parameter table 15.

When the communication control unit 11 receives the packet, it demodulates the packet and passes it to the decompression unit 12. Since the information transmitted as a packet from the image transmitting apparatus 1 is only the main part of the compressed image data, the data passed to the decompression unit 12 is only the main part of the compressed image data. The decompression unit 12 decompresses the compressed image data body with reference to the parameters written in the parameter table 15. And the extension unit 1
2 is converted into an analog signal by the DAC 13 and displayed on the monitor 14.

As described above, in this image transmission system, only the compressed image data itself is transmitted.
The amount of information to be transmitted can be reduced, the transmission time can be reduced, and the transmission efficiency can be improved as compared with the conventional system shown in FIG. In fact, according to experiments, when compression encoding is performed by the JPEG method, the data amount of the compressed image data body is about 2 kbytes to 30 kbytes, and in the case of an average image, it is about 7 kbytes. Data volume is 500 bytes to 600 bytes
It has been confirmed that the transmission information amount can be reduced by less than 10% by transmitting only the compressed image data itself without transmitting the header, as described above, because it is about bytes.

As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment, and various modifications are possible. For example, the present invention can be generally applied to image transmission.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an image transmission device, an image reception device, and an image transmission system using the same according to the present invention.

FIG. 2 is a diagram illustrating a configuration example of a conventional image transmission device, image reception device, and image transmission system using the same.

FIG. 3 is a diagram showing a structure of data generated in a compression encoding unit 3.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image transmission apparatus, 2 ... A / D converter, 3 ... Compression coding part, 4 ... Communication control part, 5 ... Camera, 10 ... Image receiving apparatus, 11 ... Communication control part, 12 ... Decompression part, 13 ... D / A converter, 14 monitor, 15 parameter table, L
Communication line.

Claims (3)

[Claims] An image transmitting apparatus for compressing an image by a predetermined compression encoding and transmitting the compressed image data, wherein only a compressed image data body is transmitted without transmitting a parameter used for performing the compression encoding. An image transmitting apparatus, comprising: 2. An image receiving apparatus for receiving only compressed image data itself, comprising a table in which parameters used when expanding the received compressed image data are registered. Image receiving device. 3. An image transmission system in which an image transmitting apparatus and an image receiving apparatus are connected by a communication line, wherein the image transmitting apparatus compresses the image by a predetermined compression encoding and transmits the image. The parameters used for the transmission are not transmitted, only the compressed image data itself is transmitted, and the image receiving apparatus has a table in which the parameters used for expanding the received compressed image data are registered. And decompressing the received compressed image data with reference to parameters registered in the table.