Vector quantization with 3-D gradient motion compensation
Choon Lee, Morton Nadler · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1990
Several new methods for vector quantization of image sequence were developed in this paper. The 3-d gradient operator1 and the newly developed stochastic gradient operator was used to estimate the motion vector on the present frame in a pixel-bypixel basis. Two new methods of block motion estimation using the pixel motion vectors were studied. The methods either use the pixel motion vectors directly on the moving block or calculate the block motion vector from the pixel motion vectors. Then for both of the methods, the differences between the prediction block and the moving block are vector quantized. The gradual deterioration of the image frames due to the incorrect matching of the code vectors and the difference blocks could be suppressed with the stochastic gradient operator and a simple smoothing filter for the prediction values. Good quality images for video conferencing applications could be obtained with the bit rate in the neighborhood of 0.15.