| 摘要 |
<p>A digitized image is divided into blocks and a wavelet transform is performed, producing wavelet blocks which are quantized, scanned into linear sequences, then coded. The scanning of each wavelet block starts with a purely low-frequency element. The high-frequency elements are scanned in a sequence that depends on the occurrence of non-zero elements among the high-frequency elements. When a non-zero element is scanned, this information is used to proceed quickly to related high-frequency elements. This scanning method tends to produce a linear sequence in which non-zero elements are clustered together. Such sequences can be coded efficiently.</p> |
