| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an image expansion method for a conversion code for obtaining an expanded image at a high-speed with high image quality, in a hierarchical wavelet/sub-band transformation. SOLUTION: In the image expansion method for a conversion code for obtaining an expanded image from coded image data, when the code subjected to hierarchical wavelet transformation is expanded into a natural image, the size of the expanded image is decided to be equal to the size of a conversion coefficient of layers in existence, up to immediate upper layer + 1 of a layer, with the size of the layer of an image designated by the user on the basis of the size of an LL sub band of the uppermost layer. Furthermore, the layer wavelet conversion coefficient with the designated image size is referenced to obtain number (i) of layers satisfying an expression below, and an expanded image is obtained by conducting inverse wavelet conversion up to an optional layer in existence from the uppermost layer up to the (i+2)-th layer, where (i) is the layer number; (the size of original image)/2<(i+1)> <= designated image size < (the size of original image)/2<i> .</p> |
