Patent ID: 7362915

Claim:
A method for enhancing the contrast of an image that is represented by a digital signal representation, comprising the steps of: decomposing said digital signal representation into a multi-scale representation comprising at least two detail images representing detail at multiple scales; modifying pixel values of said detail images by at least one of said multiple scales to yield pixel values of a set of modified detail images by applying at least one conversion function to the detail images; and computing a processed image representation by applying a reconstruction algorithm to the modified detail images; wherein said conversion function is a monotonically increasing odd conversion function providing maximum amplification within an intermediate subrange of pixel values which intermediate subrange is considered most critical, said conversion function represented by a curve having a steep amplification peak causing a slope of the curve to evolve to a local minimum following a local maximum wherein the slope of the curve increases after the local minimum with the curve being concave in a positive y(x) direction after the amplification peak.