1. A similarity determining method using local binary pattern (LBP) discrimination, comprising: obtaining a target Chi square inner product based on a target LBP feature of a target image and a target kernel LBP feature to generate a target image feature vector; projecting the target image feature vector to a kernel fisher discriminant analysis (KFDA) basis vector; obtaining a query Chi square inner product based on a query LBP feature of a query image and a query kernel LBP feature to generate a query image feature vector; projecting the query image feature vector to the KFDA basis vector; and providing a similarity degree between the target image and the query image based on the projected target image feature vector and the projected query image feature vector.