System and method for automatic color matching in a multi-display system using sensor feedback control
A system for automatic color matching of multiple displays in a multi-display system. A sensor observes the output energy of each of the displays in a multi-display system and measures the difference in the color responses for a given input color. This difference is used to derive a modification function that is applied to each display. The displays are modified accordingly, and then the color is displayed again. This process is repeated until the measured values from each of the displays are within a minimum measurement error tolerance, so that the differences in displayed colors observed among the displays are minimized.
1. A method for automatic color matching of a plurality of displays in a multi-display system comprising:
(a) sending a test image to each of the a plurality of displays;
(b) capturing the test image displayed on each of the displays;
(c) measuring a color response profile for each of the displays;
(d) modifying an operating mode vector, comprising the color transfer function for each of the displays, in response to measured error in the color response profile; wherein the color transfer function is modified for at least one of the displays;
(e) applying the modified operating mode vector to the displays; and
repeating steps (a) through (e) until the measured color response profile for each of the displays is within a predetermined error tolerance;
wherein the operating mode vector is modified by a modified gradient descent optimization comprising:
(f) modifying display input RGB values;
(g) measuring the corresponding output value as observed by a sensor to generate an observed value;
(h) comparing the observed value to a target value;
(i) computing a correction factor; and
repeating steps (f) through (i) until the measured color response profile for each of the displays is within a predetermined error tolerance.
2. The method of claim 1 , wherein the correction factor is a numerical derivative based on derivative information computed from previous iterations.
3. The method of claim 2 , wherein a previously measured global projector response function is used to provide the derivative information, which is in turn used to compute the next said RGB input value.