Method of and apparatus for obtaining tone curve.

摘要

A plurality of reference tone curves are previously determined. An operator divides an original image into image regions and selects respective reference tone curves (f1(x), f2(x)) for the image regions. The operator designates weight values (w1,w2) for the respective reference tone curves. A weighted average of the respective reference tone values is calculated with the weight values to obtain a tone curve (fd(x)) employed for converting the gradation of the original image.