Patent ID: 7630511
Filing Date: 2009-12-08
Classification: G06T,G07D

Abstract:
1. A method of obtaining information about a first digital representation of a sequence of images that may be derived from a second digital representation of the sequence of images, the second digital representation having a second watermark vector belonging to a second watermark embedded therein and the method comprising the steps of: an apparatus performing the following: extracting a first watermark vector from a portion of the first digital representation that corresponds to a portion of the second digital representation in which the second watermark vector is embedded; obtaining a comparison watermark vector that is a replica of the second watermark vector; computing a degree of similarity of the first watermark vector with the comparison watermark vector; and using the degree of similarity to determine a relationship between the first watermark vector and the second watermark vector, the determined relationship not being based on whether the degree of similarity indicates a match between the first watermark vector and the comparison watermark vector; wherein the step of extracting a first watermark vector includes synchronizing at least the portion of the first digital representation with the portion of the second digital representation, wherein the second digital representation includes synchronization marks that are locatable in the second digital representation using a secret key, wherein the secret key is used to locate the synchronization marks in the first digital representation which are used to synchronize at least the portion of the first digital representation.