A camera-based method for calibrating projection color displays

摘要

Almost all presentations today are given electronically using projection display technology. In such presentations, color images often do not reproduce correctly due to lack of projector calibration. In cases where the color imagery is intended to convey an important message, this problem can severely diminish the value of a presentation. Examples include technical, educational, and marketing presentations attempting to demonstrate color and image quality effects. Depending on the severity of the miscalibration, important information such as text and graphical elements can change color name or become difficult to discern. We propose a simple technique for calibrating projection displays using a digital camera as a color measurement device. The camera is first calibrated via visual luminance matching of projected colors. A target of known RGB values then is projected on the screen, and captured with the digital camera. The camera signals are processed through the camera calibration to produce luminance signals, and the latter are used to calibrate the tone response of the projector. The approach produces a tone response correction that is satisfactory for many applications, and most importantly, eliminates the need for costly and tedious measurement of colors projected on a screen.