Method and system for compressing motion image information

Abstract

A method and system are disclosed for compressing motion image information by means of predictive coding with a high compression ratio while maintaining high image quality. An image in each frame is divided into blocks in advance, and each of all blocks is approximated by (replaced with) a single plane defined by three data representing the magnitude of the intensity of the block, the block-to-block gradient of the intensity in the x direction, and the block-to-block gradient of the intensity in the y direction. Furthermore, corresponding pixels are compared with each other in each block consisting of n×m pixels between frames, and differential information is generated-according to the comparison result. Pixels indicated as being not greater than a parameter is treated (deleted) as pixels having no difference between frames. Information compression is performed for pixels indicated as being greater than the parameter.

Description

[0001] This application is a continuation application of Ser. No. 09 / 750,118, now pending.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a method and system for compressing motion image information data by means of predictive coding with a high compression ratio and with high image quality. [0004] 2. Description of the Related Art [0005] In image signal transmission, an image signal is first converted to another signal and then coded by assigning proper codes selected according to the statistical feature of the converted signal. When the image has high redundancy within a frame as is the case with an image including a regular pattern or a plain image, there is a high correlation between adjacent pixels, and thus it is possible to predict, to a certain degree, a pixel value to be coded next from a pixel value which has already been coded. Therefore, if components which could not be predicted are extracted, and the coding is perfor...

AI Technical Summary

Benefits of technology

[0033] Furthermore, corresponding pixels are compared with each other in each block consisting of n×m pixels (n and m are integers equal to or greater than 2) between frames, and differential information is generated according to the comparison result so as to reduce redundant information between frames. That is, pixels t in a frame are compared with corresponding pixels t−1 in a previous frame, pixel by pixel, and 1-bit bit map is generated which indicates whether the absolute value of t

Problems solved by technology

In the case of a motion image in a video telephone or the like, images of adjacent frames are very similar to each other, and thus the temporal change is limited.

However, in the conventional image signal compression technique, because of the complexity of the block coding process, it is difficult to achieve both a

Images