| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an image encoder and an image decoder for encoding and decoding a multi-gradation image with a high picture quality by using a code capable of progressively displaying the resolution when decoding the image. <P>SOLUTION: In a facsimile equipment 1, an input multilevel image is divided into blocks of an arbitrary form to be a processing unit of encoding by an image blocking part 31, a two-dimensional (2D) wavelet transformation is applied to the blocked image by a 2D wavelet transforming part 32, and the order of coefficients for first encoding a coefficient in the low-order hierarchy of a low resolution is determined for the resulting transformation coefficient by a coefficient order control part 33. Then, the coefficient is divided into blocks in an arbitrary size for encoding in the relevant order of coefficients by a coefficient blocking part 34, the coefficient is encoded for each blocked coefficient by a coefficient encoding part 35, and a code quantity is controlled by a code quantity control part 35. Therefore, while fixing the code quantity, the code capable of progressively displaying the resolution can be easily prepared when decoding the image. <P>COPYRIGHT: (C)2003,JPO</p> |
