1.给定一幅图象，输出其直方图 2.通过对话框给定一个线性变换函数，实现图象的灰度拉伸； 3.实现对图象的均衡化-1. To set an image, the output of its histogram 2. Through the dialog box to set a linear transformation function, implementation of the gray-scale image stretching 3. To achieve a balance