Enhancing the tonal and color characteristics of digital images using expansive and compressive tone scale functions

摘要

A method of enhancing the tonal and chrominance characteristics of a digital image, includes receiving a source digital image including a plurality of pixels wherein the source digital image is in a luminance-chrominance representation having a luminance digital image channel and at least two chrominance digital image channels; producing a tone scale function that can be used to enhance the tonal characteristics of the source digital image; classifying the tone scale function into one of two or more categories based on the effect the tone scale function will have on the numerical range of pixel values of a processed digital image wherein the classification categories include expansive and compressive; using the tone scale function and the luminance digital image channel to produce an enhanced luminance digital image channel; and amplifying the chrominance digital image channels to produce modified chrominance digital channels when the tone scale function has been classified as expansive. <IMAGE>