1. A method of generating reference features sets on a basis of a reference image of an object, said reference features sets for use in an image processing function configured to recognize the object and/or estimate pose information of the object from an image frame obtained from a digital imaging device by matching extracted features of the image frame with the reference features sets, the method comprising: extracting a first reference features set from the reference image; obtaining a first slice of the reference image, wherein the first slice is a first portion of the reference image; extracting a second reference features set on the basis of the first slice; obtaining a second slice of the reference image, wherein the second slice is a second portion of the reference image and wherein the first and second portions partially overlap; extracting a third reference features set on the basis of the second slice; generating metadata for the reference image, the first slice and the second slice, said metadata comprising information indicating a hierarchical relationship between the reference image, the first slice and the second slice, wherein the metadata comprises at least one of: hierarchical relationship information, parent-child relationship information, sibling relationship information, relative distance information, relative positioning information, and sizing information; and identifying, from the extracted reference features sets, the reference features sets belonging to the object, based on the generated metadata for the reference image, the first slice and second slice.