This paper introduces a new watermarking modulation technique,

which we call improved spread spectrum (ISS). Unlike in traditional

spread spectrum (SS), in ISS the carrier signal does not act

as a noise source, leading significant performance gains. In typical

examples, the gain of ISS over SS is 20 dB or more in signalto-

noise ratio or 20 orders of magnitude or more in error probability.

The proposed method achieves roughly the same noise

robustness gain as quantization index modulation (QIM). Nevertheless,

while QIM is quite sensitive to amplitude variations, ISS

is as robust in practice as traditional SS.

PDF file

Publisher  IEEE

Details