L1 = imread('portrait.jpg');
L2 = imread('portrait1.jpg');
figure;
imshow(L1);
figure;
imhist(L1);
figure;
imshow(L2);
figure;
imhist(L2);
L1a = imadjust(L1,[120/255 220/255],[0 1]);
figure;
imshow(L1a);
figure;
imhist(L1a);
L2a = imadjust(L2,[0 120/255],[0 1]);
figure;
imshow(L2a);
figure;
imhist(L2a);