output image from simulink and matlab code are different ??

I have built a simulink model to do watershedding as apart of project. The output I get from the simulink function block is quite different from matlab code version of the same program. I am attaching the code I used for both matlab and simulink and their output images

>>

if true
  % a=imread('medtest.png');
b=watershed(a);%%MATLAB CODE
d=imshow(b);
c=label2rgb(a);
figure
imshow(c);
end

if true%%WATERSHEDDING
  % function y = fcn(u)
% #codegen
coder.extrinsic('watershed','imshow','label2rgb','image');
y=zeros(size(u));
y = double(watershed(u));
image(y);
end

if true %%LABEL2RGB CODE
  % function z = fcn(u)
coder.extrinsic('imshow','label2rgb');
% z=0;
z=zeros(size(u,1),size(u,2),3);
z = double(label2rgb(u));
imshow(z)

end

[Ryan Livingston]

Could you please describe the code a bit more? The top block is your code in MATLAB and the bottom two are in the Function Block, or is it something else?

Also, from the model shown, it appears that only the watershedding code is in the function block. Is that the case?