| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance image quality of a magnified picture with respect to a picture compressor and expander that reproduces the magnified picture corresponding to an original picture from a reduced picture. SOLUTION: One block (8×8 pixels) is averaged in a 1st matrix M1 (64×64 pixels) of original picture data to generate reduced picture data expressed in a 2nd matrix M2 (8×8 pixels). A matrix M21 with a prescribed offset from the 2nd matrix M2 to include one pixel P1 in the 2nd matrix M2 is obtained. Two-dimensional discrete cosine transform is applied to the 8×8 pixels of the matrix M21 to obtain reduced DCT coefficient data represented by a matrix ME. Expanded inverse discrete cosine transform is applied to the reduced DCT coefficient data to obtain a matrix M31 consisting of m×n pixels and to obtain magnified picture data. A moving direction, a moving amount of the matrix M21 with respect to the 2nd matrix M2 and values m, n are selected so that the magnified picture data are close to the original picture data to the utmost.</p> |
