Tone value sample selection in digital image processing method employing histogram normalization

摘要

A problem in digital image processing is to automatically generate a tone reproduction function that maximizes the quality of the processed image. In an improved method for generating the tone reproduction function by normalizing the histogram of a sample of tone values, the sample of tone values is selected from an image dependent "floating" contrast interval using the statistical parameters of the distribution of tone values in the sample itself for the selection criteria. A plurality of histograms are formed from the tone values in a plurality of contrast intervals, and the most nearly normal histogram is selected for normalization.