| 摘要 |
<p>PURPOSE:To transmit an approximate picture to a terminal equipment within a short time by executing frequency band division as for conversion coefficient caused by DCT in accordance with the magnitude of the sum of the two components in spatial higher harmonic and sending vector indices attended with vector quantization in the other from data narrow frequency band of the spatial higher harmonic. CONSTITUTION:Image data from an input terminal IN is equally divided into plural equal blocks by a block division part 1, and a discrete cosine conversion part 2 applies discrete cosine conversion to the image data in the respective blocks to obtain conversion coefficients. A frequency band division part 4 band-divides the conversion coefficients of respective blocks based on the magnitude of the sum of the two components of the spatial higher harmonic. A classifying part 5 classifies the conversion coefficients of the respective blocks in accordance of their energy E. A normalization coefficient arithmetic part 6 calculates normalization coefficients for each class and band, while a normalization part 7 normalizes each conversion coefficient by dividing the energy E of each band and class with the normalization coefficient and a vector quantization part 9 vector-quantizes each normalized coefficient of block under prescribed bit allocation and coverts it to a vector index, and the data is transmitted as compressed image data via a transmission data assembling part 10.</p> |
