Abstract: A method and apparatus for encoding interframe error data in an image transmission system, and in particular in a motion compensated image transmission system for transmitting a sequence of image frames from a transmitter to a receiver, employ hierarchial vector quantization and arithmetic coding to increase the data compression of the images being transmitted. The method and apparatus decimate an interframe predicted image data and an uncoded current image data, and apply hierarchial vector quantization encoding to the resulting pyramid data structures. Lossy coding is applied on a level-by-level basis for generating the encoded data representation of the image difference between the predicted image data and the uncoded original image. The method and apparatus are applicable to systems transmitting a sequence of image frames both with and without motion compensation.

Abstract: A method and apparatus, for encoding transform coefficient data representing an error or a motion description of each of a plurality of blocks in one image frame of a timed sequence of image frames, identify those blocks for which data will be transmitted, quad-tree encode, and then variable length encode the locations of the blocks. The bit rate can be controlled by varying the quantization of the encoded data and preferably quantization step size is predicted prior to encoding the data. Further, the quad-tree encoding process can be terminated after the coding process generates a selected number of bits. At the receiver, the method and apparatus provide a multiple lookup table method for decoding the variable length coded data.

Abstract: A method and apparatus for encoding and transmitting a sequence of image frames employ a measure of motion displacement for generating a motion compensated image. The motion compensated image, together with an error signal, provides the receiver with full detail regarding the next frame of a sequence. In some instances, however, the motion displacement data is inaccurate for portions of the next image frame. In those instances, the method and apparatus determine whether filtering of a portion of the motion compensated image provides a lower error energy for the resulting prediction of the image. If a lower error energy can be achieved by low-pass filtering, the data regarding the additional processing of the motion compensated reconstructed image is transmitted to the receiver.