绘制灰度直方图

octave无法完成，这个只能用matlab做

分别绘制灰度直方图和归一化直方图

pic=imread('data/1.jpg');
gray_pic=rgb2gray(pic);
figure(1);
imshow(gray_pic);
figure(2);
imhist(gray_pic);
[X,Y]=size(gray_pic);
[counts,x] = imhist(gray_pic,32);
counts=counts/(X*Y);
figure(3);
stem(x,counts);