| 摘要 |
<p>Image feature values Va and Vb are derived from image data, coefficients C and D are determined based on the image feature values Va and Vb, and an approximate expression expressed with the file size Sfj of the JPEG compression file and the quantization data coefficient value Aqt is derived. Next, by designating the file size of a desired predetermined JPEG compression file based on the approximate expression, the quantization data coefficient value Aqt is derived, and a first quantization table as a reference is multiplied by the quantization data coefficient value Aqt, whereby a second quantization table is obtained. Then, using the second quantization table, the image data is actually JPEG-compressed.</p> |
