1. An apparatus for face verification, comprising: a memory storing one or more software applications; a processor that executes the one or more software applications to: extract HIFs (Hidden Identity Features) for different regions of faces by using differently trained ConvNets, wherein last hidden layer neuron activations of said ConvNets are considered as the HIFs; concatenate the extracted HIFs of each of the faces to form a feature vector; group the HIFs into a plurality of groups in the formed feature vector for each face, each group containing HIFs extracted by same ConvNets; extract local features from each group of HIFs; extract global features from the previous extracted local features; and calculate a single face similarity score from the extracted global features so as to determine if the two feature vectors are from the same identity or not based on the calculated score.