hand gesture recognition in matlab

Question

I am doing gesture recognition in MATLAB. I need help regarding finger detection. I have detected the hand using skin color detection but don't know how to find the number of fingers. I have used bwboundary for boundaries detection in the image but it only works when the image is error free. That is, a slight disturbance in marking the hand area in the skin detection code will result in many boundaries. I would be very thankful if anybody just guides me in the right direction.

Here in the image after skin is detected and marked I used bwboundary to find out the boundaries. I have also used imfill but it still didn't help me much.

Following is the code

%Read the image, and capture the dimensions
img_orig = imread('hand.jpg');
height = size(img_orig,1);
width = size(img_orig,2);

%Initialize the output images
out = img_orig;
bin = zeros(height,width);

%Convert the image from RGB to YCbCr
img_ycbcr = rgb2ycbcr(img_orig);
Cb = img_ycbcr(:,:,2);
Cr = img_ycbcr(:,:,3);

%Detect Skin
[r,c,v] = find(Cb>=77 & Cb<=127 & Cr>=133 & Cr<=173);
numind = size(r,1);

%Mark Skin Pixels
for i=1:numind
    out(r(i),c(i),:) = [0 0 255];
    bin(r(i),c(i)) = 1;
end
imshow(img_orig);
figure; imshow(out);
figure; imshow(bin);

%now for count of fingers

img2=im2bw(bin,graythresh(bin));
imshow(img2)
img2=~img2;
imshow(img2)
B = bwboundaries(img2);
imshow(img2)
text(10,10,strcat('\color{green}Objects Found:',num2str(length(B))))
hold on