Scientists at NEC Corp’s NEC Research Institute in Princeton, New Jersey say they have developed a digital watermarking method for protecting copyrights in audio, image, video and multimedia data, particularly where it is transmitted over the Internet. IBM Corp and Digimarc Corp of Portland, Oregon have similar technology, Reuter points out, but NEC claims that its system differs from others. It says it places a watermark in perceptually significant components of a signal, which makes the removal of the watermark difficult without noticeably degrading the signal. The watermark is created using a random noise string based on spread-spectrum frequency technology, rather than pixel image-based technology. The company says the watermark is robust to common signal and geometric distortions and that the same digital watermarking algorithm can be applied to all three media – audio, image and video – with only minor modifications. The Digimarc system uses the same concept of an invisible identification code based on an algorithm permanently embedded in the data, but IBM’s digital watermark remains visible. NEC gave no licensing details but said the watermark could be included in products shortly. Digimarc’s system sounds very similar, as its patents describe a perceptually adaptive, spread-spectrum watermark system.
