1. A method for processing a video image signal represented by a plurality of lines of consecutive pixels comprising: determining a horizontal variance between consecutive pixels in the plurality of consecutive lines in conjunction with determining a vertical variance between corresponding pixels in at least two of the plurality of consecutive lines of the signal; accumulating the horizontal and vertical variances over at least one pixel window that includes horizontal variances of consecutive pixels of a line and vertical variances between corresponding pixels of the line and a consecutive line; and determining a noise measurement based on a smallest variance determined from the accumulated variances.