equalize color image histogram

eq_hist.cpp

std::vector<cv::Mat> planes;
        cv::cvtColor(mat, sharp_mat, CV_BGR2HSV);
        cv::split(sharp_mat, planes);
        cv::equalizeHist(planes[2], planes[2]);
        cv::merge(planes, sharp_mat);
        cv::cvtColor(sharp_mat, mat, CV_HSV2BGR);