Once a synthetic appearance of the restored object has been generated, the projectors need to project this appearance onto the physical object. Since excessive light intensity onto the object may further damage the object, selection of which projectors to illuminate different parts of the object is critical. In general, if a projector more directly illuminates a portion of the object, that projector should be depended on more heavily to illuminate that surface area. Similarly, if a projector is at a grazing angle to a portion of the object's surface, it should not contribute much light to that particular surface area. While simply selecting the optimally oriented projector per surface point of the object would achieve this goal, the resulting visual compensation would contain discontinuities due to adjacent surface points being illuminated by different projectors. Instead, we use a weighted balance of the given projectors to achieve a smooth compensation, emphasizing the optimally oriented projectors across the surface of the object.
In the image below, a) and b) show projector combination schemes which provide a sub-optimal appearance (discontinuities and too dim, respectively) while c) demonstrates our approach to balancing the contribution of our projectors. |