Convert a RGB image to gray with parallel processing?

I have this code under, that is convert RGB to gray, but i don't how to do with parallel processing?Any one know , help me pls

Im=imread('5.jpg');

%0.2989 * R + 0.5870 * G + 0.1140 * B

GIm=uint8(zeros(size(Im,1),size(Im,2)));

tic

for i=1:size(Im,1)

for j=1:size(Im,2)

GIm(i,j)=0.2989*Im(i,j,1)+0.5870*Im(i,j,2)+0.1140*Im(i,j,3);

end

end

toc

subplot(1,2,1), imshow(Im), title('RGB Scale image');

subplot(1,2,2), imshow(GIm), title('Gray Scale image');

Answer 1

[KSSV]

You need not to use a loop here and parallel computing. Just the below should work.

Im=imread('5.jpg');
%0.2989 * R + 0.5870 * G + 0.1140 * B
GIm=0.2989*Im(:,:,1)+0.5870*Im(:,:,2)+0.1140*Im(:,:,3);
GIM = uint8(GIm) ;       

[thanh nguyen]

but my teacher requests me to change this into parallel processing :((

Answer 2

[yanqi liu]

clc; clear all; close all
Im=imread('football.jpg');
%0.2989 * R + 0.5870 * G + 0.1140 * B
GIm=uint8(zeros(size(Im,1),size(Im,2)));
GIm2=uint8(zeros(size(Im,1),size(Im,2)));

tic
for i=1:size(Im,1)
    for j=1:size(Im,2)
        GIm(i,j)=0.2989*Im(i,j,1)+0.5870*Im(i,j,2)+0.1140*Im(i,j,3);
    end
end
toc

parpool(3)
tic
parfor i=1:size(Im,1)
    for j=1:size(Im,2)
        GIm2(i,j)=0.2989*Im(i,j,1)+0.5870*Im(i,j,2)+0.1140*Im(i,j,3);
    end
end
toc