Patent ID: 7388610

Claim:
A method of compensating data obtained from a two-dimensional array of photosensitive pixels for a shading intensity pattern superimposed on a light pattern of interest, comprising: grouping the pixels of the array into a plurality of adjacent blocks that individually have a plurality of pixels in both rows and columns thereof, storing the following in a memory: at least one base value of the shading intensity pattern of at least one pixel of the array, and increments of change of the shading intensity pattern between pixels across the array in both rows and columns of individual blocks, including a first rate of change of the shading intensity pattern along individual pixels in the row direction and a second rate of change of the shading intensity pattern along individual pixels in the column direction, calculating compensation factors for the individual pixels from said at least one base value and said increments, and combining the calculated compensation factor with data obtained from said individual pixels of the array, thereby to correct the data obtained from the pixels for the shading intensity pattern.