Watermarking an information signal
AssigneeKoninklijke Philips Electronics N.V.
InventorJohan P. M. G. Linnartz
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Abstract
A method and an arrangement for detecting a multi-bit watermark in a signal (e.g. a video image) are disclosed. Each bit of the multi-bit value is represented by an embedded watermark subpattern in the signal. Instead of detecting in a conventional manner the presence of each individual subpattern (i.e. detecting each individual bit), the detection comprises the steps of: detecting (24,23) the presence of the full watermark in the signal irrespective of its multi-bit value, and detecting (25) to which extent the presence of subpatterns corresponds with the multi-bit value to be checked. The reliability of watermark detection is hereby improved.
Claims2
A method of embedding a multi-bit watermark in a video image by adding a watermark pattern to said image, comprising the steps of:
- dividing (11, 12) the video image and said watermark pattern into blocks, the blocks of the watermark pattern constituting subpatterns;
- and
- representing (10) each bit (w1 . . . wn) of the multi-bit value by choosing the adding or not adding a subpattern to a corresponding image block in accordance with a corresponding bit (w1 . . . wn) of the multi-bit value.
An arrangement for embedding a multi-bit watermark in a video image (P) by adding a watermark pattern (W) to said image, comprising:
- means for dividing (11,12) the video image and said watermark pattern into blocks, the blocks of the watermark pattern constituting subpatterns;
- and
- means for choosing the adding (10) or not adding a subpattern to a corresponding image block in accordance with a corresponding bit (w1 . . . wn) of the multi-bit value.
Dependencies are inferred from the claim text.