Inspec keywords: face recognition; image classification; graph theory; gradient methods; feature extraction; transforms; vectors

Other keywords: illumination variation; AWOGBP; scale factor; feature vector; subgraph weight; adaptively weighted orthogonal gradient binary pattern; face image classification; information entropy; Tetrolet transform; face recognition

Subjects: Computer vision and image processing techniques; Image recognition; Integral transforms; Algebra; Interpolation and function approximation (numerical analysis); Interpolation and function approximation (numerical analysis); Combinatorial mathematics; Integral transforms; Combinatorial mathematics; Algebra