【Gabor滤波】经典的二维Gabor滤波器核函数由一个高斯包络与一个复指数(复数正弦波)载波构成,其一般形式为:g ( x , y ; θ ) = exp ( − x ′ 2 + γ 2 y ′ 2 2 σ 2 ) ⋅ exp ( i ( 2 π x ′ λ + φ ) ) g(x, y; \theta) = \exp \left( -\frac{x'^2 + \gamma^2 y'^2}{2\sigma^2} \right) \cdot \exp \left( i \left( 2\pi \frac{x'}{\