clear Y1=imread(‘lena2.jpg‘); Y1=rgb2gray(Y1); figure imshow(uint8(Y1)); vmax=max(max(Y1)); vmin=min(min(Y1)); C1=255/double(vmax-vmin); Y2=C1*(Y1-vmin); Y2=round(Y2); figure imshow(uint8(Y2));
clear
X=imread(‘lena.jpg‘);
X=rgb2gray(X);
[m,n]=size(X);
N=zeros(1,256);
for i=1:m
for j=1:n
k=X(i,j);
N(k+1)=N(k+1)+1;
end
end
figure;
subplot(1,2,1);
imshow(uint8(X));
subplot(1,2,2);
bar(N);
axis tight;

原文:https://www.cnblogs.com/Bran-don/p/10552552.html