The present invention provides steganographic embedding techniques. A
digital watermark signal is reduced to a set of spatial positions. The
set of spatial positions sufficiently conveys the digital watermark
signal. Message objects are positioned according to the set of spatial
positions. Non-message objects are combined with the message objects to
form an image or design. The message objects include distinguishable
characteristics, e.g., via color, contrast, gray-scale level or
luminance, in comparison to the non-message objects. The digital
watermark signal is detected by distinguishing the message objects from
the non-message objects (e.g., via color or contrast differences) and
analyzing the relative placement of the message objects within the image
or design.