JPH02243083A - Picture transmitting device - Google Patents

Abstract

PURPOSE:To facilitate the signal processing in centralized monitor while dispersion in a picture transmission time is eliminated by counting a code quantity outputted from a picture compression means and setting a threshold level of the picture compression means so that the counted code quantity is constant. CONSTITUTION:A picture data picked up by a TV camera is compressed by a discrete cosine transformation and Huffman coding at a picture compression means 1. The code quantity outputted from the means 1 is counted by a code quantity count means 2 and a threshold level setting means 3 sets a threshold level of the means 1 so that the code quantity counted is made constant. That is, when the code quantity counted by the means 2 is larger than a preset prescribed quantity, the threshold level is increased and when the code quantity is smaller than the prescribed quantity, the threshold level is decreased to obtain the compressed picture information with the prescribed code quantity. The code quantity set from a code transmission means 4 through a transmission line such as a telephone line is always made constant and since the dispersion the picture transmission time is eliminated, the signal processing in the centralized monitor is facilitated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image transmission device that compresses image data of images taken with a TV camera or the like and transmits the compressed image data via a telephone line or the like. be.

[Prior Art] Conventionally, this type of image transmission device that compresses and transmits image data of images obtained by shooting with a TV camera, etc. A large amount of image data (for example, image data taken with a T-camera) is compressed by an image compression means using orthogonal transform such as discrete cosine transform, and then transmitted by a code transmission means.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional example, when trying to use it for purposes such as monitoring, the compression rate varies depending on the monitoring screen, so the code amount of the pressure a image varies. However, there is a problem in that the image transmission time varies, which is a particular problem when images transmitted from a plurality of monitoring locations are centrally monitored at a central monitoring center.

The present invention has been made in view of the above points, and its purpose is to provide an image transmission device that eliminates variations in image transmission time and facilitates signal processing in centralized monitoring. It is in.

[Means for Solving the Problems] The image transmission device of the present invention includes an image compression means for compressing image data, a code amount counting means for counting the amount of codes output from the image compression means, and a code amount counting means for counting the amount of codes outputted from the image compression means. It consists of a threshold value setting means for setting a threshold value of the image compression means so that the image compression means is constant, and a code transmission means for transmitting the code of the compressed image.

[Function] The present invention is configured as described above, and the image data of the image taken by the TV left camera is compressed by the image compression means and transmitted to a transmission line such as a telephone line by the code transmission means. The image transmission device includes: code amount counting means for counting the amount of codes output from the image compression means; and threshold setting means for setting a threshold of the image compression means so that the counted amount of codes is constant. This eliminates variations in image transmission time and facilitates signal processing in centralized monitoring.

[Embodiment] FIG. 1 shows an embodiment of the present invention, which includes an image compression means 1 for compressing image data, a code I counting means 2 for counting the amount of codes output from the image compression means 1, and a The image compressing means 1 is comprised of a threshold setting means 3 for setting a threshold of the image compression means 1 so that the amount of encoded code is constant, and a code transmission means 4 for transmitting the code of the compressed image. In the embodiment, the image compression means 1 performs image compression using discrete cosine transformation and Huffman encoding. Further, each of the above means can be formed by software using a microcomputer, but if the image compression means 1 is configured by hardware, image compression can be performed in real time, and the threshold value and the sign l are in a monotonically decreasing relationship. Therefore, the adjustment of the code amount is completed before the image is transmitted.

The operation of the embodiment will be described below. Now, the image data of the image taken by the TV left camera etc. is compressed by the image compression means 1 by discrete cosine transformation and Huffman encoding.0 The code I output from the image compression means 1 is , is counted by the code amount counting means 2, and the threshold value setting means 3 sets the threshold value of the image compression means 1 so that the counted code amount is constant. That is, when the code amount counted by the code amount counting means 2 is larger than a predetermined amount set in advance, the threshold value is increased, and when it is less than the predetermined amount, the threshold value is decreased. Compression means 1
Compressed image information with a predetermined amount of code can be obtained from. Therefore, the amount of code transmitted from the code transmission means 4 through a transmission path such as a telephone line is always constant,
Since variations in image transmission time are eliminated, signal processing in centralized monitoring can be easily performed.

[Effects of the Invention] The present invention is configured as described above, and the image data of the image taken by the TV left camera is compressed by the image compression means, and is transmitted to a transmission line such as a telephone line by the code transmission means. In the image transmission device configured to transmit the image, the code amount counting means counts the code amount output from the image compression means, and the threshold value setting means sets a threshold value of the image compression means so that the counted code amount is constant. This has the advantage that it is possible to eliminate variations in image transmission time and facilitate signal processing in intensive monitoring.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of one embodiment of the present invention. 1 is an image compression means, 2 is a code amount counting means, 3 is a threshold setting means, and 4 is a code transmission means. Agent Patent Attorney Ishi 1) Choshichi

Claims (1)

[Claims] (1) An image compression means for compressing image data, a code amount counting means for counting the amount of codes output from the image compression means, and a threshold value of the image compression means is set so that the counted amount of codes is constant. An image transmission device comprising a threshold value setting means and a code transmission means for transmitting a code of a compressed image.