2. Features extraction of uniform LBP (ULBP) based on Gabor
wavelet
2.1. Gabor wavelet
Gabor wavelet kernel function has the same characteristics as 2D
reflection region of the human brain’s cortex simple cell. It can capture
the information of different spatial frequency, spatial location, direction,
and extract the local nuances effectively. Well, filtering process of
face image can not only enhance some of the key characteristics but
also has better robustness of local deformation.
The Gabor wavelet kernel function can be defined as