title: Using imfilter_mex directly avoiding imfilter
body: <p>Recently I've started using imfilter function to make a convolution of an image with some kernel. I have to run this function several thousands of times. Therefore I decided to time calls that are made by this function. </p>
  
  <p>It's turned out that really a lot of time is spent on argument checking, checking some toolbox preferences(functions like useIPPL(a,outSize,h,nonzero_h)) and other different preparations. Eventually everything comes to imfilter_mex calls.</p>
  
  <p>Now the questions is: is I know my filters are not separable, I know that I will give correct parameters as inputs, how do I use properly this mex interface provided by Mathworks?</p>
  
  <p>Initially, this mex located in private folder of image processing toolbox. Since it cannot be found be default, I've tried to moved in project's directory.</p>
  
  <p>Since that time calls are randomly crashing with not obvious logic. Does anyone have any experience of using this mex directly?</p>
  
  <p>Thank you </p>
  
  <p>small update: crashes have Access Violation type, I have to kill matlab after each crash</p>