Is there a way to overcome For loops for fast processing?

I have written a following MATLAB code to detect skin color pixels from the RGB image. The output is as expected but being pixel by pixel algorithm, my program is taking too long, expecially for high quality images. Is there a way to take out the for loops for fast processing? Thank you.

[s1,s2,s3] = size(I);
skin_img1 = zeros(s1,s2,s3);
maxR = max(max(R));
minR = min(min(R));
maxG = max(max(G))
minG = min(min(G));
maxB = max(max(B));
minB = min(min(B));
for i = 1:s1
    for j = 1:s2
         if R(i,j)>90/255
           if ( G(i,j)>40/255 && B(i,j)>20/255 && abs(R(i,j)-G(i,j))>15/255 && R(i,j)> G(i,j) && R(i,j) > B(i,j)...
                   && (max([R(i,j),G(i,j),B(i,j)])- min([R(i,j),G(i,j),B(i,j)]) >15/255));
%                (maxR - minR)>15/255 && (maxG - minG)>15/255 && (maxB - minB)>15/255 )  
            skin_img1(i,j,:) = I (i,j,:);
           end  
%          else
%            if( R(i,j)> G(i,j) && R(i,j) > B(i,j) && R(i,j) - G(i,j)> 5/255 && (abs(G(i,j)-B(i,j))>5/255))
%             Skin_Image(i,j,:) = I (i,j,:);
%            end
        end
    end
end

[KALYAN ACHARJYA]

Attach sample image, so that we can try on it? Skin color?

[Muhammad Farhan Mughal]

One of the figure from internet is

Answer 1

[Muhammad Farhan Mughal]

Following MATLAB code significantly reduced the computatonal cost of the questioned code

R = I(:,:,1);
G = I(:,:,2);
B = I(:,:,3);
R = double(R);
G = double(G);
B = double(B);


R = R/255;
G = G/255;
B = B/255;

[s1,s2,s3] = size(I);
skin_img1 = zeros(s1,s2,s3);
index1 = zeros(size(R));
R1 = R(:) ; G1 = R(:); B1 = B(:); 
mat_I = [R1,G1,B1]';
index = R >90/255 & G > 40/255 & B>20/255 & abs(R-G)>15/255 & R> G & R > B &...
            reshape((max(mat_I)- min(mat_I)) >15/255, [s1,s2]);
index = uint8(index);
skin_img = repmat(index,[1,1,3]).*I;

[darova]

What if i have different skin color?

[Muhammad Farhan Mughal]

Actually I needed to do work with that algorithm. That's why I was looking for the fast processing of that particular algorithm. However, I appreciate your effort in this regard as from your answer I got the clue of using indexing.

[darova]

Can i use your code for my study research?

Not for commercial purposes

[Muhammad Farhan Mughal]

Yes, you can I also wrote that code for research purposes.

[darova]

Answer 2

[darova]

See attached script

clc, clear

A = imread('masson.jpg');
subplot(1,2,1)
imshow(A)

RGB = [40 120 40];      % color you want
e = 40;                 % color shift / deviation

B = pix_in(A,RGB,e);
B = B + 255.*uint8(~B);        % choosing white background
subplot(1,2,2)
imshow(B)

[Muhammad Farhan Mughal]

Thank you @darova for the reply, It is somehow a little different.

[darova]

Isn't that you wanted?

[Muhammad Farhan Mughal]

Yes, this is what I wanted, I have also reduced the computational cost and sharing my code as well.

[Muhammad Farhan Mughal]

I have accepted your this answer but I am not getting the same output as yours.

[darova]

Did you try to change Color you want?

[Muhammad Farhan Mughal]

No, I didn't.

[darova]

Good. Don't do this