error in using improfile

I have a image below

in this i have used the following code

fg is the binay image
 fg=logical(fg);
    [area, bbox] = step(hblob, fg);

      image_out = img;%it is frame extracted from video
      image_out(22:23,:,:) =0;  
      image_out(1:15,1:30,:) = 0;  
      image_out(110:111,:,:) = 0; 
      Idx = bbox(:,2) > line_row; 

      ratio = zeros(length(Idx),1);
      ratio(Idx) = single(area(Idx,1))./single(bbox(Idx,3).*bbox(Idx,4));
      ratiob = ratio > 0.4;
      count = int32(sum(ratiob));    
      bbox(~ratiob,:) = int32(-1);

      image_out = step(hshapeins, image_out, bbox);

      image_out = step(htextins, image_out, count);  

      xline=[3.0000  154.0000]
   yline=[23.0000   23.0000]
  % 
   c=improfile(image_out,xline, yline)
      res{n}=sum(c(:));

in this for all 120 images i get values as 0,even if car vehicle the line it is showing zero,y i am getting like this ,plz help

http://www.sendspace.com/filegroup/xPtPRFmZZkBQMwcnT430fw http://www.sendspace.com/file/j1y7ey