Patent ID: 7420602
Filing Date: 2008-09-02
Classification: H04N

Abstract:
1. A CMOS imager, wherein the CMOS imager comprises: an image sensor, wherein the image sensor includes one or more rows of pixels, and wherein each of the pixels provides a pixel value; a storage element; a summing circuit, wherein the summing circuit is operable to sum the pixel values for each of the one or more rows to create row sums, and to store the row sums to the storage element, wherein the row sums are created for each of a plurality of frames; and a programmable core, wherein the programmable core includes instructions executable by the programmable core to: determine a first energy value and a second energy value associated with the row sums for each of the plurality of frames; calculate a variance between the first energy values across the plurality of frames; calculate a variance between the second energy values across the plurality of frames; compare the variance of the first energy values with the variance of the second energy values to estimate a flicker frequency; and constrain an exposure duration associated with the image sensor to approximate a multiple of the flicker duration.