| 摘要 |
<p>A video telephone system includes a camera (14) that produces video images. Processing circuitry (88, 100) performs vector quantization on the video images to represent the video images with a relatively small amount of data for transmission to a remote location or memory (fig. 7). The video images are represented by frames which may be further divided into blocks (54). A current block is the block that is being considered at a given time. A conditional previous block occupies the position in a previous frame that the current block occupies in the current frame. A motion previous block is a block of the previous frame (42A) containing data like that of the current block. To further reduce the amount of data needed to represent the video images, the processing circuitry (88, 100) determines what, if any, quantization is needed with respect to the current block. The processing circuitry (88, 100) may perform either vector quantization on the current block, or vector quantization on a residual (68) between the current block and motion previous block, or pass bits indicating that the vector quantization of the conditional previous block is adequate. The decision (96) which occurs depends on various distances related to the current block, the motion previous block, and the conditional previous block. The invention has application for images other than those used in video telephone systems.</p> |
