http://study.marearts.com/2014/05/open-cv-get-histogram-and-compare-color.html
https://www.jianshu.com/p/bd12c4273d7dhttps://docs.opencv.org/3.4/d8/dc8/tutorial_histogram_comparison.html
opencv直方图比较
原文：https://www.cnblogs.com/lijiale/p/12133361.html
