title: Imshow not able to update image when using Haar Cascade opencv
body: <p>I had used Haar-Cascade to detect human on a thermal image in raspberry Pi. In order to improve the model performance, i had used 2000 of images to train the model. Now the model size is 201kb. Previously it was 60kb and 89kb when i trained the model with less no. of images. As I use 201kb model and detect the human and display it on the screen using IMSHOW, Imshow doesnot update the image in real time, there is so much of delay or even imshow gets hangs. It works fine for 60kb and 89kb model. 
  I even tried using opengl to display the image in real time but no help.</p>
  
  <p>What should i do to make the output display similar to real-time using imshow?</p>