The optimum predictive image is selected as follows for the entire area of an image sequence comprising a luminance signal expressing each pixel value, and a transmittance signal expressing the transparency of each pixel value, and described by the transmittance signal of the target image to be coded...http://www.google.de/patents/US5969765?utm_source=gb-gplus-sharePatent US5969765 - Object-based digital image predictive coding transfer method and apparatus, and decoding apparatus
