Encoding of a picture signal in consideration of contrast in each picture and decoding corresponding to the encoding

Abstract From the Canadian patent

On encoding an original picture signal comprising signal portions representative of original pictures respectively, a, contrast detecting unit (41) detects a measure of contrast in each picture in response to signal blocks representative of block areas, respectively, which have a common size in the picture in the manner known in transform encoding. Such measures are variable in a predetermined number of stages. With reference to the stages, a picture encoding parameter determiner (72) determines picture encoding parameters, Supplied with the encoding parameters a picture encoder (71) encodes the original picture signal into an encoded picture signal. Inasmuch as the measures are detected in …