Patent ID: 7206430
Filing Date: 2007-04-17
Classification: G06T,H04N

Abstract:
1. A detecting data processing apparatus operable to identify one or more of a predetermined set of code words present in a marked version of an original material item, said marked version having been formed by combining a plurality of samples of said original material item with one of a corresponding plurality of code word coefficients, said apparatus comprising: a registering processor operable to associate samples of said original material item with corresponding samples from said marked version of said material item with which corresponding code word coefficients may have been combined, a recovery processor operable to generate a recovered code word by comparing samples of said original material item with corresponding samples of said marked material version, a correlation processor operable to generate, for each of said code words in said predetermined set of code words a correlation value by correlating the recovered code word with each of the generated code words, and a detection processor operable to detect said one or more code words from the corresponding correlation value for the code word exceeding a predetermined threshold, wherein said registering processor is operable to form a representation of a correlation of the samples of said original material item and the samples of said marked version, for each of a plurality of respective shifts of said original material item with respect to said marked version of said material item, and to determine a first registration position of said original material item with respect to said marked material item, from the respective shift producing the highest correlation value, wherein said registering processor is operable to over sample said original material item and said marked version of said material item, to form said representation of the correlation of the over sampled versions of said original material item and said marked version, for a plurality of respective shifts with respect to said first registration position, and to determine a second registration position from the respective shift of said over-sampled versions having the highest correlation value.