Adding extra digital information to an analog image signal

Describes a method for adding extra digital information to images. Such a method is called bit-add. The principle of such a bit-add system is based on having quantizers with more than one representation level for each decision interval. The extra information decides which of these levels to use. Bit-add introduces additional quantization error to the image signals. The described method has the possibility to distribute the error in a picture such that the error is least visible. In simulations the author added 648 kb/s to the luminance part of an image signal without serious impairments