Matlab Intro - Image Processing

A='d:\t1.jpg';
B=imread(A, 'jpg');
C=rgb2gray(B);
imhist(C)
imhist(C, 256)
imhist(C)
D=imadjust(C, [0 1], [0 1]);
imshow(D);
E=histeq(C);
imshow(E);
F=graythresh(C);
G=im2bw(C,F);
imshow(G);