Method and apparatus for gray level signal processing
High efficiency technique for coding a digital video signal
Highly efficient coding apparatus for a digital video signal
Encoding apparatus with two stages of data compression Patent #: 5166987
ApplicationNo. 794218 filed on 11/19/1991
US Classes:358/426.03, Transfer rate of an uncoded or decoded image358/426.12, Auxiliary information transmitted (e.g., required to perform or identify decoding technique)375/240.24Block coding
ExaminersPrimary: Coles, Sr., Edward L.
Assistant: Rogers, Scott A.
Attorney, Agent or Firm
Foreign Patent References
International ClassesH04N 001/417
Foreign Application Priority Data1990-11-20 JP
AbstractDigital video signals are divided in blocks, maximum and minimum values of each block are extracted, and a frequency distribution of one frame period of a dynamic range in each block is detected. The coding condition is determined by the frequency distribution and a predetermined N kinds of characteristic tables, and by determining only one characteristic table, the signal obtained by subtracting the minimum value of each block from the digital video signals of each block is coded in variable length according to the dynamic range of each block. The characteristic table shows the relationship of the distortion or the number of quantization bits between the original signal and decoded signal after coding and decoding with respect to the dynamic range of digital video signal in each block, and the picture quality of decoded image is set as a parameter.
Field of SearchVariable thresholding technique