Working on hand detection

I have found a code for face detection which is:

%Detection of Face on the basis of skin color clear all;

close all;

clc

I=imread('filename.jpg','JPEG');

imshow(I)

cform = makecform('srgb2lab');

J = applycform(I,cform);

figure;imshow(J);

K=J(:,:,2);

figure;

imshow(K);

L=graythresh(J(:,:,2));

BW1=im2bw(J(:,:,2),L);

figure;imshow(BW1);

M=graythresh(J(:,:,3));

figure;imshow(J(:,:,3));

BW2=im2bw(J(:,:,3),M);

figure;imshow(BW2);

O=BW1.*BW2;

% Bounding box

P=bwlabel(O,8);

BB=regionprops(P,'Boundingbox');

BB1=struct2cell(BB);

BB2=cell2mat(BB1);

[s1 s2]=size(BB2);

mx=0;

for k=3:4:s2-1

    p=BB2(1,k)*BB2(1,k+1);

    if p>mx & (BB2(1,k)/BB2(1,k+1))<1.8

        mx=p;

        j=k;

    end
end

figure,

imshow(I);

hold on;

rectangle('Position',[BB2(1,j-2),BB2(1,j-1),BB2(1,j),BB2(1,j+1)],'EdgeColor','r' )

WHAT CHANGES COULD BE MADE IN THIS CODE TO DETECT HAND INSTEAD OF FACE?