基于CIELAB的舌诊专用比色卡的设计与验证OA

Objective To address the color deviation issues in tongue image acquisition caused by equipment and lighting,a specialized color chart for tongue diagnosis was designed based on the CIELAB color space to achieve color correction of tongue images,and its correction effect was verified.Methods Real tongue images were analyzed to design the color chart in combination with the IT8.7/4 standard color table.The algorithm for color correction was selected through comparative experiments,and the color stability of the color chart was verified via color stability tests.Color correction was performed using a 3×3 matrix and Gamma correction algorithm.A total of 1200 tongue images were obtained under multiple light sources(3 natural light sources and 3 artificial light sources)and with multiple devices(6 types of smartphones)in real-world scenarios for subjective and objective verification.For objective validation,the changes in images before and after correction were analyzed based on the Lab color difference value(ΔE).For subjective validation,tongue images collected by a tongue diagnostic instrument from the same subject were used as the standard reference.The Kappa coefficient was calculated based on the interpretations of pre-correction and post-correction images by different physicians to test the consistency,and the effectiveness was evaluated through the physicians'diagnostic accuracy in judging tongue color and coating color.Results A U-shaped special color comparison card for tongue diagnosis was designed,which included 17 color patches related to tongue colors.The color correction was achieved using a 3×3 matrix and Gamma correction algorithm.Objective verification showed that after correction,the color difference values of tongue color patches in each light source and device group decreased from 5-40 to 0-10 significantly(P<0.01).The effects under natural light and white light were the best,and the correction effect of mobile phones with high pixels and partial real colors was better.In the subjective verification,the Kappa value for tongue color increased from 0.19 to 0.44,and that for coating color rose from 0.59 to 0.71.The accuracy rate of tongue color interpretation increased from 26.73%to 63.05%,and that of tongue coating color increased from 38.47%to 70.91%.Conclusion The specialized color chart for tongue diagnosis effectively reduces color deviations caused by lighting and equipment,providing a convenient and accurate solution for remote TCM diagnosis,construction of multi-center tongue image databases,and objective analysis of tongue image features,thus promoting the objectification of tongue diagnosis.