A Color Control Method for Image Output with Projection Displays

摘要

The present paper proposes a nonlinear approach using a neural network for color control of projection displays, including the LCD and DLP types. This approach accepts variations in primary color coordinates and coupling among RGBW channels. We regard a display system as an unknown nonlinear system with RGB signal inputs and XYZ tristimulus outputs. We determine the RGB values so that the projector outputs the desired XYZ values. The neural network is used for estimating adaptively an inverse mapping from the XYZ space to the RGB space. Because of a direct mapping, we can eliminate the need to predict white channel separation. Moreover, we present a method for correcting the emitted luminance, according to the spatial location and the surface color of a screen. The spatial correction is needed because a color image from a computer is not displayed uniformly on the screen. Also the screen color correction is needed because color reproduction is based on the light reflected from the screen. The correction makes it possible to reproduce accurate color images on a colored wall at any location.