Patent ID: 7307752
Filing Date: 2007-12-11
Classification: G06F,H04N

Abstract:
1. A method for calibrating a dynamically varying color reproduction device from an output image generated in response to a target test including steps of: producing an image with the device in response to an input signal from the test target wherein the test target comprises a preselected neutral gray color; measuring with a sensor an output signal representative of the output image corresponding to the target preselected color; determining an error between the output signal of the image and the input signal; adjusting a tone reproduction curve (TRC) of the device to minimize the determined error for a plurality of preselected colors only wherein the plurality include C, M and Y values of preselected neutral gray colors, and wherein a set of desired controlled points corresponding to values of a plurality of test targets on the TRC are formed; and, constructing a full color TRC for the device from the controlled points for calibrating the device color output comprising adjusting a set of three one-dimensional TRCs wherein each of the TRCs corresponds to a one of the C, M and Y values, whereby the device is expeditiously calibrated by iterating the adjusting for the plurality of preselected colors until the error is less than a predetermined value and the TRC adjustment avoids connecting a three parameter three-dimensional look up table in favor of the set of three one-dimensional adjustment TRCs.