ORDINAL AND SPATIAL LOCAL FEATURE VECTOR BASED IMAGE REPRESENTATION

A local image patch identified in an image is divided into respective sub-patches of respective image forming elements. For each of the respective image forming elements in the local image patch, a respective ordinal rank of the image forming element is determined, and respective contributions of the image forming element to a particular one of the respective sub-patches containing the image forming element and to one or more other ones of the respective sub-patches neighboring the particular sub-patch are ascertained. Each ordinal rank corresponds to a respective dimension of an ordinal rank feature space. For each of the respective sub-patches of the local image patch, a respective histogram of ascertained contributions of the image forming elements in the ordinal rank feature space is built. A respective feature vector representing the local image patch is generated from the respective histograms built for the sub-patches of the local image.