读入彩色图片，将其转换成灰度图像，然后画出它的灰度直方图，将灰度值压缩到64-192，画出灰度直方图，最后画出直方图均衡化后的图像以及直方图-Read into a color picture, convert it to grayscale image, and then draw its gray level histogram, the gray value is compressed to 64-192, draw the gray histogram, and finally draw the image after histogram equalization and histogram