[数字图像处理]灰度直方图均衡化

 1 function [  ] = histChange( A )
 2 %histChange 此处显示有关此函数的摘要
 3 %对输入图像矩阵进行灰度直方图均衡化,若输入为RGB图像矩阵，则自动转换为灰度图像进行处理
 4 %
 5 [M,N,a]=size(A);
 6 if a == 3
 7     B=rgb2gray(A);
 8 else
 9     B=A;
10 end
11 x=0:255;
12 y=zeros(1,256);
13 s=zeros(1,256);
14 subplot(2,2,1);
15 total=0;
16 for k=1:M
17     for p=1:N
18         y(B(k,p)+1)=y(B(k,p)+1)+1;
19         total=total+1;
20     end
21 end
22 
23 bar(x,y);
24 y=y/total;
25 for k=1:256
26     for m=1:k
27         s(k)=s(k)+y(m);
28     end
29 end
30 s=s*255;
31 subplot(2,2,2);
32 imshow(B);
33 for k=1:M
34     for p=1:N
35         B((k),(p))=s(B(k,p));
36     end
37 end
38 subplot(2,2,4);
39 imshow(B);
40 u=zeros(1,256);
41 for k=1:M
42     for p=1:N
43         u(B(k,p)+1)=u(B(k,p)+1)+1;
44     end
45 end 
46 subplot(2,2,3);
47 bar(x,u);
48 end