色差公式在评价显示图像颜色中有效性的测试

Test of Validity of Color Difference Formulae in Evaluating Color Accuracy of Displayed Images

目前,还没有统一的评价图像颜色准确性的方法,当前使用的所有色差公式都是基于均匀颜色色差计算的。提出了一种检验彩色显示器模拟印刷图像颜色准确性的方法。用降低图像像素的方法提取测试图像中的典型颜色值,将这些典型颜色显示在显示器上并用仪器测量颜色,获得显示颜色与颜色目标值的偏差。实验测量和计算了显示图像的色差,并对图像进行了目视评价,检验了各种色差公式计算色差与目视评价色差的相关性。用CIEDE76、CIEDE94、CIEDE2000、CMC(1∶1)和CMC(2∶1)色差公式计算的结果表明,CIEDE76色差公式计算的图像色差与目视评价结果相关性很差,近中性色的计算色差明显小于目视色差,绿色区域的计算色差大于目视色差。在5种色差公式中,CMC(2∶1)的计算结果与目视结果一致性最好。

There is no best method to calculate and evaluate color difference of images. All color difference formulae are established base on uniform test color patch. A new method to evaluate color accuracy of displayed images is proposed, which samples the typical color values from the images and measures them on the display. The measured color difference calculated by CIEDE76, CIEDE94, CIEDE2000, CMC（1 ： 1） and CMC（2 ： 1） color differences formulae are compared with subjective evaluation difference and consistency. The experiment results show that CIEDE76 color difference is much smaller than subjective perceived difference in the near neutral color area and that in the green area is larger than perceived difference, so that the consistency between measured and perceived color differences is very poor. The results also show that CMC（2 ： 1） color difference is the best one for evaluating color images among the 5 color difference formulae.