Generalised alpha scale spaces quadrature filters

Generalised alpha scale alpha spaces quadrature filters

This code implements a part of the papers:
Ahror BELAID and Djamal BOUKERROUI. "A new generalised alpha scale spaces quadrature filters." Pattern Recognition 47.10 (2014): 3209-3224.
Ahror BELAID and Djamal BOUKERROUI. "Alpha scale space filters for phase based edge detection in ultrasound images." ISBI (2014): 1247-1250.

It is a new families of band pass quadrature filters, built from derivatives and difference of the α scale space generating kernels. This construction leads to generalised α kernel filters including the commonly known families derived from the Gaussian and the Poisson kernels.