Patent ID: 6771839
Filing Date: 2004-08-03
Classification: H04N

Abstract:
An efficient method of computing conversion tables for performing gamma conversion transformation on a pixel-by-pixel basis between two representations of an image, said method comprising the steps of:(a) determining a non-linear transform between input values in a first range and output values in a second range, said non-linear transform having at least one adjustable parameter; (b) determining at least one approximation equation to said non-linear transform, said at least one approximation equation having coefficient values ci; (c) for each coefficient value ci, grouping together all of the coefficient values over a range of said at least one adjustable parameter and fitting an approximation to each grouping to get a respective coefficient approximation equation; (d) computing coefficients for a given value of said at least one adjustable parameter using said coefficient approximation equations; (e) computing conversion transformations using the computed coefficients and a simplified mathematical formula; and (f) storing the computed conversion transformations in a conversion table.