| 摘要 |
To convey hidden messages (words) on a TV display (12), the word(s) in digital format cause field to field background brightness variation in selected areas (13) without affecting the detail within the areas. The variation in brightness is not detectable by a human user, but only by a photo detector probe coupled to a decoder. By making the number of "0" and "1" bits in a word always different, flickering is reduced. <IMAGE> |
