The need is met according to the present invention by providing a method of correcting pixel by pixel variations in a display, the method including the steps of creating a defect map of pixel intensity offsets for the display; correcting an input signal according to the defect map; and displaying the corrected input signal on the display, wherein the offset defect map is created by modulating a pixel in the display at a predetermined rate at a predetermined intensity; sensing the display with a photosensor to generate a sensed signal; demodulating the signal with a synchronous demodulator at the predetermined rate to produce a demodulated signal representing a sensed intensity; and employing the sensed intensity and the predetermined intensity to generate a correction offset.