| 摘要 |
PROBLEM TO BE SOLVED: To shorten a time required for conversion processing to attain acceleration while suppressing the deterioration of image quality. SOLUTION: This pixel number converter 1 is provided with: a pixel type discrimination part 2 which detects change point pixels (contour point pixels or boundary point pixels) included in a binary image (original image 10); a mask processing part 3 which sets a pixel number converted image 20 in which the number of pixels in the main scanning and vertical scanning directions of the binary image is increased or decreased according to conversion magnification, and sets pixels corresponding to the change point pixels on the original image 10 in a mask area 32 to generate a converted mask image 30 out of the pixel number converted image 20; a first gradation acquisition part 4 which calculates a density value of the pixels belonging to the mask area 32 of the converted mask image 30 by density calculation processing using a projection method, and binarizes the density value by binarization processing using an error diffusion method to obtain a gradation value; and a second gradation acquisition part 5 which sets a gradation value of pixels belonging to a non-mask area 33 of the converted mask image 30 to a gradation value which the pixel on the original image 10 corresponding to that pixel has. COPYRIGHT: (C)2011,JPO&INPIT |
