| 摘要 |
PROBLEM TO BE SOLVED: To divide an image into blocks and to precisely separate image areas of a dot, a character and a photograph by using DCT.SOLUTION: Image processing means of an image processor includes: a division section for dividing image data inputted from image input means in block units; a DCT conversion section for performing DCT conversion on pixels of individual blocks; a zigzag scan section for zigzag-scanning a frequency component except for a DC component in frequency components on which DCT conversion is performed; a zigzag rate calculation section for doubling target data for checking a peak of scanned data and calculating a value obtained by subtracting data before and behind a value as a zigzag rate; a determining section for calculating sums of absolute values of the zigzag rates in a low frequency band, a high frequency band and a whole frequency band and determining each block as one of a character, a dot and a photograph by using the calculated sums of the low frequency band, the high frequency band and the whole frequency band; and a processing section for performing filter processing on each determined block according to whether the block is one of the character, the dot and the photograph. |
