| 摘要 |
PURPOSE:To improve picture quality up to a maximum degree by applying selectively the optimum binary conversion system according to the picture quality from each part of a variable density picture. CONSTITUTION:A gradient calculator 7 calculates a density gradient based on a density value for the picture of various density stored in a line buffer 6. The calculator 7 controls an HPF8 and outputs an input signal as it is to a tissue dither threshold value circuit 10 without filtering it when the density inclination is small. Where the density inclination is large, the binary conversion is performed by the circuit 10 appropriate to a picture binary conversion with great variety, this selectively enabling adaption of the optimum binary conversion system according to the picture quality from each part of the picture of various density.
|
