| 摘要 |
PROBLEM TO BE SOLVED: To obtain an excellent image in which production of moire is suppressed by deciding a thershold level depending on a state of a reference picture element or its surrounding picture elements in the resolution converter binarizing image data. SOLUTION: Registers 2-4 store the lattice width in the X direction and registers 5-7 store the lattice width in the Y direction, and a projection filter 8 has three product sum arithmetic circuits 8a-8c. The lattice width in the X, Y directions and a reference picture element are given to the filter 8, and the reference picture element refers to image data of three lines simultaneously and they are stored in reference picture element shift registers 9-11. Since an output of the filter 8 assumes 256 gradations, the high-order 8-bits as the result of product sum arithmetic operation are obtained from an adder 16. As the binarization processing, an output of the adder 16 and a threshold level Th from a threshold level calculation circuit 13 are compared by a comparator 18, and when the output of the filter 8 is higher than the threshold level, the comparator 18 provides an output of '1' as a black level picture element and when not, the comparator 18 provides an output of '0' as a white level picture element. A shift signal #2 is set to write the binarization picture element bit as above to a shift register 19. |
