- 1. the camera does not move;
- 2. the background lighting in the scene is quite stable (when doing
- background subtraction it is recommended to disable auto-gain in the
- camera, and avoiding any artifact introduced by the power line
- frequency).
+A few conditions are required to create a decent effect:
+
+ 1. the camera should not move;
+ 2. the lighting in the scene should be quite stable (when doing background
+ subtraction it is recommended to disable auto-gain in the camera, and
+ avoid any artifact introduced by the power line frequency);
+ 3. the subject should enter the scene only after the background learning
+ phase has finished, i.e. after opencv_trail_effect has shown the preview
+ window.