This paper presents a visible watermarking system using
%how and why
A watermark image is overlaid translucently onto a primary image,
for the purposes of immediate claim of copyright, instantaneous
recognition of owner or creator,
or deterrence to piracy of digital images or video.
The watermark is modulated by exploiting
combined DCT-domain and
DWT-domain perceptual models. % so that the watermark is visually uniform.
The resulting watermarked image is
visually pleasing and unobtrusive.
The location, size and strength of the watermark
vary randomly with the underlying image. The randomization
makes the automatic removal of the watermark difficult even though
the algorithm is known publicly but the key to the random sequence generator.
The experiments demonstrate that the watermarked images have pleasant
visual effect and strong robustness. The watermarking system can be used in
copyright notification and protection.