MORE DETAILS ON EMBEDDING SIGNATURE CODES INTO MOTION PICTURES
Just as there is a distinction made between the JPEG standards for compressing still images and the MPEG standards for compressed motion images, so too should there be distinctions made between placing invisible signatures into still images and placing signatures into motion images. As with the JPEG/MPEG distinction, it is not a matter of different foundations, it is the fact that with motion images a new dimension of engineering optimization opens up by the inclusion of time as a parameter. Any textbook dealing with MPEG will surely contain a section on how MPEG is (generally) not merely applying JPEG on a frame by frame basis. It will be the same with the application of the principles of this invention: generally speaking, the placement of invisible signatures into motion image sequences will not be simply independently placing invisible signatures into one frame after the next. A variety of time-based considerations come into play, some dealing with the psychophysics of motion image perception, others driven by simple cost engineering considerations.
One preferred embodiment is the following. This example actually uses the MPEG compression standard as a piece of a solution. Other motion image compression schemes could equally well be used, be they already invented or yet to be invented. This example also utilizes the scrambled logo image approach to generating the master snowy image as depicted in FIG. 13 and discussed in the disclosure.
A "compressed master snowy image" is independently rendered as depicted in FIG. 15. "Rendered" refers to the generally well known technique in video, movie and animation production whereby an image or sequence of images is created by constructive techniques such as computer instructions or the drawing of animation cells by hand. Thus, "to render" a signature movie in this example is essentially to let either a computer create it as a digital file or to design...