Chroma Measurement Of LED Display Screen With Color Bayer Camera

The color uniformity of LED display was a important indicator of evaluating LEDdisplay show quality. Now, LED display color measurement was mainly traditionalluminance meter and camera with color filter, but traditional luminance meter measurewas inefficiency, camera with color filter measurement accuracy can’t meet accuracyrequirements. Therefore, how color camera with color filter accurately and effectivelymeasure LED display chrominance information was particularly important.This paper analyzed the problems in LED display chroma measurement from colorcamera imaging mechanism. The analysis results were three main questions:high-frequency aliasing caused by camera undersampling; the missing color of Bayerpattern color image; the color space calibration. The method was propriety defocusingblurring in camera capture image process; then rebuild bayer-type color image by colorratios interpolation; Finally, convert RGB color value which were extracted LED lightsto CIEXYZ color value by polynomial transforms. This method can achieve the purposeof the LED display chromaticity measurements.The results showed that: the measurement chroma error between camera andcolorimeter was0.002, the luminance error was1%. This method could capture colorvalues of LED display quickly and accurately, achieve chromaticity correction withhigh-precision, finally improve show effects of LED display dramatically.