图像直方图的绘制，此程序提供两种方法，一是利用matlab自带得工具箱绘制，另一种是利用统计学的方法编程实现，最后对两种方法进行比较-Image histogram drawing, this program provides two methods, one using matlab toolbox comes too draw, another is the use of statistical methods to program implementation, and finally to compare the two methods