1. A method for determining similarity between an image and at least one training sample, comprising the steps of: a. iteratively for said image and each of said at least one training sample: i. generating a preprocessed image; ii. calculating an augmented Gabor feature vector from said preprocessed image; iii. deriving a lower dimensional feature vector from said augmented Gabor feature vector; iv. processing said lower dimensional feature vector with a lower dimensional feature space discriminator; v. deriving an overall transformation matrix from said lower dimensional feature vector and said lower dimensional feature space discriminator; and vi. calculating a image feature vector; and b. determining a similarity measure for said image and said at least one training sample.