Color Correction for Tongue Digital Imaging

In order to improve the color accuracy of tongue digital image, the color correction method was established based on a special color target for color correction of tongue image, and the color response of digital imaging device has been corrected accordingly. Firstly, a one-dimensional lookup table for each monochromatic channel was established which transfers the color of gray blocks in color correction target from imaged RGB to the corresponding sRGB; Then convert the color after one-dimensional transformation to sRGB by color correction matrix. The two-step color correction method achieved accuracy evaluated by CIE DE2000 with the average /maximum value of 1.14/3.23 and 3.01/5.19 for 30 test colors of imaged by two devices. The color correction accuracy of tongue image in traditional Chinese medical has been satisfied.