Patent ID: 6804408
Filing Date: 2004-10-12
Classification: H04N

Abstract:
A method for enhancing a digital image channel comprised of a plurality of image pixels, said method comprising the steps of:providing a predetermined estimate of the noise expected for the digital channel based on a predetermined relationship between the image intensity values and expected noise for given intensities; generating a local estimate of signal activity for the digital image channel; generating a gain adjustment from the predetermined estimate of noise provided in said providing step and the local estimate of signal activity generated in said first generating step; applying the gain adjustment to the image pixels in the digital channel in order to generate a digital channel with enhanced image values; splitting the digital image channel into first and second channels that substantially comprise the digital image channel, said first and second channels each characterized by image intensity values corresponding to the image pixels; providing image values from the second channel corresponding to image pixels from a region of the image: identifying a statistical characteristic of the image pixels in the region; normalizing a predetermined tone scale conversion for the statistical characteristic in order to generate a normalized tone scale conversion; and performing the normalized tone scale conversion on a central pixel of the region to generate a second channel with enhanced image values; and combining the first channel and the second channel with enhanced image values to generate an enhanced digital image channel.