CONTOUR EMPHASIS METHOD AND ITS DEVICE

摘要

PROBLEM TO BE SOLVED: To adjust the width of a black edge and a white edge and to freely control the effect of contour emphasis in a high contrast part without emphasizing graininess of a low contrast part. SOLUTION: Gradation of a main signal to be inputted is corrected by a first gradation correcting part 11 having conversion characteristics which projects upwards or downwards. An averaging processing is performed for an obtained signal M1, by adapting a smoothing filter with a specified mask size and an unsharp signal U1 is obtained. A second gradation correcting part 13 is provided with the conversion characteristic of an inverse conversion of the first gradation correcting part 11, and an unsharp signal U2 is obtained by correcting the gradation of the unsharp signal U1 at the second gradation correcting part 13. An unsharp mask signal (M-U2) is obtained by a subtracter 14. Then the unsharp mask signal (M-U2) is multiplied by a constant, added to the main signal, and outputted.