This software implements the full strategy as presented in the paper
"Real-time nonparametric background subtraction with tracking-based foreground
update", by D. Berjón, C. Cuevas, F. Morán and N. García.

It takes two mandatory plus two optional parameters:
1. Path to the directory containing the sequence of images to be used as input.
2. Path to the directory where the output images are to be written (if it does 
   not exist, it will be created; if it does exist, its previous contents will
   be DELETED).
3. Number of reference images for the background model (default=200).
4. Appearance sigma for the foreground model (default=0.02).

Output images represent Pr(φ|x^n) using a linear scale where black is 0 and 
white is 1.

The binary has been compiled for 64-bit Linux systems and it depends on the 
following external libraries to be installed:
- CUDA Runtime, version 4.x
- FreeImagePlus, version 3.x
- Boost.Filesystem and Boost.System, version 1.54
- Qt, version 5.x
