Patent ID: 7692700

Claim:
A method to compensate vignetting in digital cameras comprising: providing a read-Only memory (ROM), a lens system, a processing device, a RAM, a test chart, an array of pixel-based sensors, and a camera unit; take a picture of said test chart during production of said camera; analyze said test image in regard of brightness of pixels independently of color sensitivity of said pixels during production of said camera; fit test image with a polynomial surface function using said brightness during production of said camera; insert the coefficients of said polynomial function in a matrix during production of said camera; store said matrix in said read-Only memory (ROM) during production of said camera; retrieve said matrix from said read-Only memory (ROM); construct a polynomial surface function using coefficients retrieved; build a gain table using said polynomial surface for all pixels of the image; and apply values of said gain table to all pixels of the image taken to compensate vignetting, wherein said compensation of vignetting is performed by multiplying pixel-by-pixel a normalized polynomial function with the raw pixel values of each picture taken.