Low visibility watermarks using an out-of-phase color

A method of embedding a media signal with a digital watermark signal, the media signal comprising a first color plane, a second color plane, a third color plane, and a fourth color plane, said method comprising the steps of:

• combining the watermark signal with the first color plane, second color plane and third color plane;
• inverting the digital watermark signal;
• and
• combining the inverted digital watermark signal with the fourth color plane.

A method of conditioning a signal including an out-of-phase embedded watermark for watermark detection, the out-of-phase embedded watermark being embedded in a media signal comprising a plurality of color channels, said method comprising the steps of:

• determining a luminance value per pixel for a first set of the plurality of color channels;
• determining a luminance value per pixel for a second set of the plurality of color channels;
• and
• subtracting the second set's luminance value from the first set's luminance value.

A method to condition a signal for recovery of an out-of-phase digital watermark which is embedded in a media signal in a first color scheme, the media signal being subsequently converted to a second color scheme, said method comprising the steps of:

• designating each pixel in the converted media signal as at least either a first color, a second color or a third color;
• creating a first color plane and a second color plane based on color designations in said designating step;
• determining a luminance value per area for each of the first color plane and second color plane;
• and
• on an area by area basis, subtracting the second area's luminance value from the first area's luminance value.