Method for watermarking data
First Claim
1. A method of incorporating a watermark into a signal, comprising substituting a replaceable signal portion of the signal which has a substantially random attribute with a replacement signal, the replacement signal portion having a substantially random attribute which has been modulated by watermark data.
2 Assignments
0 Petitions
Accused Products
Abstract
A method for inserting a watermark into an audio signal comprising substituting a noise-like signal portion with a replacement noise-like signal portion, and the replacement noise-like signal portion is modulated with watermark data. In a preferred embodiment Perceptual Noise Substitution is used to locate those portions of the audio signal which are noise-like and which may be replaced by synthetic noise modulated with watermark data.
Advantageously the inventive method results in a signal having a synthetic noise signal portion which is modulated by watermark data but which is perceived merely as a noisy signal portion and not as watermark data carrying. Furthermore, watermarks incorporated by the inventive method may be adapted to be robust to various audio compression schemes.
28 Citations
34 Claims
- 1. A method of incorporating a watermark into a signal, comprising substituting a replaceable signal portion of the signal which has a substantially random attribute with a replacement signal, the replacement signal portion having a substantially random attribute which has been modulated by watermark data.
- 26. A method of reading a signal which is provided with a watermark, comprising locating a replacement signal portion (10) and identifying the presence of the watermark in said replacement portion, the replacement signal portion having a substantially random attribute which has been modulated by watermark data, the replacement signal portion having replaced a replaceable signal portion which has a substantially random attribute.
-
33. An encoder (3) comprising a signal analyser (5), a random signal generator (8) and a modulator (7), the arrangement being such that in use the signal analyser analyses a signal so as to determine a replaceable signal portion (10) which has a substantially random attribute, the modulator being operative to modulate a replacement signal portion generated by the random signal generator with watermark data, and the replaceable signal portion being substituted by the replacement signal portion.
-
34. A reader (14) comprising a signal analyser (15), a random signal generator (17) and a demodulator (18), the arrangement being such that in use the signal analyser analyses a signal in order to determine the presence of a watermark in the signal, the watermark being incorporated into the signal by way of a replacement signal portion (10) and the replacement signal portion having a substantially random attribute which has been modulated by watermark data.
Specification