Patent ID: 8280183

Claim:
A method for enhancing a contrast of an image, comprising: estimating a noise level of the image; deriving a first signal from a pixel of the image based upon the noise floor using a first infinite-impulse-response filter, wherein the first signal represents a brightness of the image pixel; deriving a second signal from the image pixel using a second infinite-impulse-response filter, wherein the second signal represents an illumination intensity of the image pixel; and amplifying a difference between the first and second signals; wherein the step of deriving a first signal further comprises applying the first infinite-impulse-filter to a luminance component of the image, wherein a set of coefficients of the first infinite-impulse-filter is determined by a temporal and spatial recursive process having a coefficient that is derived from a set of differences between the first signal and a luminance component of the image at a group of image pixel locations; and wherein the step of deriving a second signal further comprises applying the second infinite-impulse-filter to a luminance component of the image, wherein a set of coefficients of the second infinite-impulse-filter is determined by a temporal and spatial recursive process having a coefficient that is derived from a variable and a chrominance component of the image, wherein said variable is derived from a recursive process for a group of image pixels.