Filter with Gabor Kernel using FFT

Filter an image with M*N Gabor kernels, return the result. Use FFT to accelerate.

[G GWINLEN] = genGaborKernelF( MU,NU,sigma,scaleXY,imgSz )
GIMG = GABORCONV(IMG,G,GWINLEN)
Extract the texture feature using Gabor filter/wavelet. You should first generate cell array G, which is a set of kernels in freq domain, then pass G and the image to the function GABORCONV.