Digital imaging colorimeter for fast measurement of chromaticity coordinate and luminance uniformity of displays

Color and luminance uniformity testing of displays is often limited to fewer than ten measurements points on the display surface due to the length of time necessary to make a single point measurement. A CCD-based digital imaging tristimulus colorimeter has been developed which is capable of measuring luminance and chromaticity coordinates at over one million spatial locations in several seconds. The Four-Color Method of colorimeter calibration, recently proposed by NIST, has been employed and found to be superior to single point calibration using Illuminant A. Color and luminance uniformity of a CRT and LCD display were measured using the new digital imaging tristimulus colorimeter and a diode array spectrometer. The data show that chromaticity coordinate and luminance measurements using the CCD-based imaging tristimulus colorimeter compare favorably with the point measurements obtained using a diode array spectrometer over the color gamut of a CRT and LCD display.