| 摘要 |
PURPOSE:To detect the direction of general density change independently of distortion due to the characteristics of an input device by estimating missed density information to be originally expressed in a picture. CONSTITUTION:A density level expanding circuit 9 reads the contents of a picture memory, outputs a picture obtained by expanding its density level once to a a picture work memory 8, and at the end of one picture, reads the contents of the picture work memory 8 and outputs a picture obtained by expanding its density level once to the picture memory 7. Said processing is repeated, and when the density level can not be expanded moreover, a density gradient detecting circuit 10 is started. The circuit 10 reads out the contents of the memory 8, calculates the density inclination, outputs the calculated result to a correcting circuit 11 and actuates the correcting circuit 11. The circuit 11 reads out the contents of the memory 8 on the basis of the read density gradient to correct the contents and outputs the corrected result to the picture memory 7. |
