% party.m reads a file, displays it and its red, green, and blue components

F = 'party_72.png';                   % specify the file name

imfinfo(F)                            % display image information
P=imread(F);                          % read image into M by N by 3 matrix

size(P)
class(P)                              % tell what type of number A contains

clf

subplot(2,2,1)
imshow(P,'truesize');
title('Original image')

subplot(2,2,2)
Q = P;
Q(:,:,2) = min(P(:,:,2),0);
Q(:,:,3) = min(P(:,:,3),0);
imshow(Q,'truesize');
title('Red component only')

subplot(2,2,3)
Q = P;
Q(:,:,1) = min(P(:,:,1),0);
Q(:,:,3) = min(P(:,:,3),0);
imshow(Q,'truesize');
title('Green component only')

subplot(2,2,4)
Q = P;
Q(:,:,1) = min(P(:,:,1),0);
Q(:,:,2) = min(P(:,:,2),0);
imshow(Q,'truesize');
title('Blue component only')