Patent ID: 8345994

Claim:
A method comprising: providing an associative dataset comprising data associating a hash code with respective pixel data of at least an image sub region of a first image, the at least an image sub region having a predetermined size; using a first processor processing image data of a second image indicative of an object for dividing the second image into at least an image sub region having the predetermined size and determining location data indicative of a location of the at least an image sub region within the second image; using the first processor determining for the at least an image sub region of the second image a hash code in dependence upon pixel data of pixels located in the at least an image sub region of the second image; and, using the first processor transmitting for the at least an image sub region of the second image one of: the hash code together with the location data if the hash code exists in the associative dataset; and, the pixel data together with the location data if the hash code does not exist in the associative dataset, wherein the hash code is determined as a function of the pixel data in the image sub region, and wherein a hash function is used that produces a substantially uniform distribution of hash codes over a set of possible values of the pixel data in the image sub region.