imfindcircles in MATLAB Function Block

Im trying to implement a MATLAB function in Simulink which takes a RGB image (120*160*3) and outputs a logical '1' if a circle is detected.

CODE

function y = fcn(I)
  img = I ;
  cDetect = false ;
  img = rgb2gray(img);
  img = edge(img);
  radii = [] ;
  centers = [] ;
  [centers, radii] = imfindcircles(img,[10 60],'Sensitivity', 0.8,'EdgeThreshold',0.5);
  if(~isempty(radii))
     cDetect = true ;
  end
  y = cDetect ;

But I keep getting an error in the imfindcircles part, But when I implement the same code purely in MATLAB, It works.

Here is the diagnostic part.