自动视觉检测是机器视觉的一个重要研究领域，而颜色分级是自动视觉检测中的一个典型问题，在陶瓷、木材等行业应用广泛。为了实现快速自动分级，根据人类视觉特性，提出了一种基于均匀颜色空间的表面颜色分级方法。该方法首先将数据从RGB颜色空间转换到CIE 1976 L^ a^ 均匀颜色空间；然后在CIE 1976 L^ a^ 空间用RWM(radius weighted mean)方法提取主导颜色(dominant colors，DC)，再以此作为颜色特征，提出了一种新的颜色距离度量——映射色差，并分析了它与平均色差的关系；最后以映射色差为距离度量，采用最小距离分类器来进行颜色分级。实验结果说明该方法是有效的。

Automatic visual inspection is one of the most important areas of machine vision. Color grading is one of the typical issues in automatic visual inspection, and has been broadly used in ceramic tiles, lumber etc. In order to implement grading quickly, accurately and automatically, a color grading method based on perceptually uniform color space is put forward according to human vision system characteristics. Firstly, color data in RGB like color space is transformed into perceptually uniform color space-CIE 1976 L *a *b *. In CIE 1976 L *a *b * color space, 2-D RWM (radius weighted mean) cut algorithms are applied to extract DC (dominant colors), which is not sensitive to lighting change and less computation complexity compared to 3-D RWM cut algorithms. Then, DC set as color feature, an innovative color distance metric-mapping color difference is proposed, which is identical to human visual system characteristic. The relation between mapping color difference and average color difference is also analysed. Finally, mapping color difference used as distance metric, anaminimum distance classifier is adopted to color grading. Experiments results show that the proposed method is effective and encouraging.