The metric code (CCPR, CCFR and Escore) described in  

@inproceedings{knn_matting_cvpr12,
        AUTHOR = "Cewu Lu, Li Xu and Jiaya Jia",
        TITLE = "Contrast Preserving Decolorization with Perception-Based Quality Metrics",
        BOOKTITLE = "International Journal of Computer Vision (IJCV) ",
        YEAR = "2014"}
 
 Please download COLOR250 dataset form authors' website.    