Untitled

I=imread("peppers.png")
[m,n,c]=size(I);
J=zeros(m,n );
J1=zeros(m,n );
for i=1:m
    for j=1:n
        J(i,j)=(I(i,j,1)+I(i,j,2)+I(i,j,3))/3;
        J1(i,j)=(0.299*I(i,j,1)+0.587*I(i,j,2)+0.114*I(i,j,3))/3;
    end;
end;
figure;
subplot(2,2,1);
imshow(I);
title("original");
subplot(2,2,2);
imshow(J,[]);
title("");
subplot(2,2,3);
imshow(J1,[]);