Given an occlusion graph for a group of objects that contains no binary cycles, and a set of antialiased images with transparency for each of the (isolated) objects, image compositing operators can be used to produce a correct, antialiased image of the objects with hidden surfaces eliminated. We show how an appropriate image compositing expression is derived given the occlusion graph, and how the resulting expression can be put in canonical form so as to require only two image registers for evaluation, or alternately, three registers for efficient evaluation.

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