MATLAB 灰度图直方图均衡化

cl;
img=imread('mask.jpg');
imshow(img);
[x,y]=size(img);
img_man=zeros(x,y);
img_com=zeros(x,y);

%% 直方图均衡化算法
Max=max(max(img));
Min=min(min(img));
Hist=zeros(1,256);
for i=1:x
    for j=1:y
        Hist(img(i,j)+1)=Hist(img(i,j)+1)+1;
    end
end
figure,plot(Hist);

p=zeros(1,256);
for i=1:256
    p(i)=Hist(i)/(x*y);
end
figure,plot(p);

c=zeros(1,256);
for i=1:256
    c(i)=sum(p(1:i));
end
figure,plot(c);

for i=1:x
    for j=1:y
        img_man(i,j)=c(img(i,j)+1)*(Max-Min)+Min;
    end
end

figure,imshow(uint8(img_man))

Hist2=zeros(1,256);
for i=1:x
    for j=1:y
        Hist2(img_man(i,j)+1)=Hist2(img_man(i,j)+1)+1;
    end
end
figure,plot(Hist2);

%% matlab直方图均衡化函数
img_com=histeq(img);     
figure,imshow(img_com)

Hist3=zeros(1,256);
for i=1:x
    for j=1:y
        Hist3(img_com(i,j)+1)=Hist3(img_com(i,j)+1)+1;
    end
end
figure,plot(Hist3);