| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To minimize block distortion of an image in decoding since a substitute value substituting a pixel where a character/line drawing pixel is present is set to a value for nearly eliminating generation of a DC component after frequency conversion when an image including both a gray-scale image and characters/line drawings is encoded in block units. <P>SOLUTION: A block processing unit 901 inputs image data to a block of 8×8 pixels. An extracting unit 902 extracts pixel data of the characters/line drawings as extracted color information and also extracts position information specifying character/line drawing pixel positions. A substituting unit 903 substitutes a substitute value determined on the basis of pixel data having gray-scale properties for the pixel data extracted as the characters/line drawings in the image data input to the block. At this time, the substituting unit 903 determines as the substitute value a value close to a DC component value after frequency conversion when it is assumed that the input block has only pixels having gray-scale properties. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
