| 摘要 |
PURPOSE:To reduce drastically encoding rate without causing the deterioration of picture quality, and to realize effective picture compression in the case that a three-dimensional sub-band picture signal obtained by blocking a digital picture signal after sub-band-dividing it according to frequency is encoded. CONSTITUTION:After the digital picture signal is divided into four sub-bands according to the frequency by a sub-band division circuit 5, each sub-band picture is made into a three-dimensional block. A sub-band block is given orthogonal transformation by a three-dimensional orthogonal transformation circuit 6, and a transformation coefficient is obtained, and simultaneously, it is decided whether each three-dimensional sub-band block is a moving picture or a still picture. In the case of the still picture, the transformation coefficients in the three-dimensional blocks of all frequency bands are encoded by an encoder 7. In the case of the moving picture, the three-dimensional block of a high frequency band is omitted, and the transformation coefficients, in the other three-dimensional blocks are encoded by the encoder 7. |
