发明名称 INTERFRAME CODING SYSTEM WITH AUTOMATIC CONTROL OF MAGNITUDE OF INTERFRAME DIFFERENCE SIGNAL
摘要 <p>An input video signal is fed to a subtractor wherein a difference is taken between the input and the output from a frame memory to provide a difference signal, the magnitude of which is controlled by a magnitude adjuster. The controlled output is then fed to a threshold circuit, from which a significant difference signal is derived which has a magnitude above a given level. The significant difference signal is quantized by an encoder into a code having a reduced number of bits as compared with the inputted significant difference signal. The quantized code is written into a buffer memory, and is read out therefrom at a uniform bit rate to a transmission line. A sum of a signal indicative of the representative level of the quantized code from the encoder and the output of the frame memory is formed in an adder, and the sum signal is written into the frame memory and read out subsequently or after one frame. The occupancy of the buffer memory is detected to provide a control over the magnitude adjuster in accordance with the detected value so as to prevent an overflow from the frame memory. A signal to refresh the frame memory located on the receiving side is transmitted by writing the output of the adder into the buffer memory after switching from the output of the encoder to the output of the adder.</p>
申请公布号 CA1042097(A) 申请公布日期 1978.11.07
申请号 CA19750237690 申请日期 1975.10.15
申请人 NIPPON TELEGRAPH & TELEPHONE PUBLIC CORPORATION 发明人 KURODA, HIDEO;KANAYA, FUMIO
分类号 G06T9/00;H04N7/32;H04N7/36;(IPC1-7):04N7/00 主分类号 G06T9/00
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