| 摘要 |
PROBLEM TO BE SOLVED: To provide a picture quality correcting circuit for keystone correction, which corrects a featured part of input data more intensely. SOLUTION: The picture quality correcting circuit for keystone correction is equipped with: a pixel selection portion which selects and outputs sixteen pixels from at least four or more lines of input video data; and an enlargement/reduction filter which obtains one pixel data to be outputted by multiplying sixteen pixel data by a filter coefficient respectively and adding them together and interpolates or thins out pixels at fixed intervals according to a set enlargement or reduction rate, wherein between the pixel selection portion and enlargement/reduction filter, the picture quality correcting circuit is equipped with: a DCT processing portion which finds sixteen DCT coefficient values by performing discrete cosine transformation processing using sixteen pixel data from the pixel selection portion; a picture quality correction portion which applies arithmetic processing as correction for emphasizing the featured part to the DCT coefficient values; and an IDCT processing portion which performs inverse discrete cosine transformation processing using the corrected DCT coefficient values and outputs sixteen corrected pixel data. COPYRIGHT: (C)2006,JPO&NCIPI
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