This paper discusses two efficient methods for image based rendering. Both algorithms approximate the world object. One uses the convex hull and the other uses the visual hull. We show that the overhead of using the latter is not always justified and in some cases, might even hurt. We demonstrate the method on real images from a studio-like setting in which many cameras are used, after a simple calibration procedure. The novelties of this paper include showing that projective calibration

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... s for this computation and providing simpler formulation that is base only on image measurements. ¤ ¤ ¦ ¥ § © where ¥ is the number of pixels in the new image and © is the number of planes. A better way to do this is to compute the dual convex hull of the planes and use the resulting edges to divide the image into at most ¥ convex polygons as shown in figure 4(a), each corresponds to a facet of the convex hull. Computation of the dual convex hull is ¤ ¤ © ¥ © and the mapping of each polygon can be done via the graphics hardware and thus is independent of the number of pixels. The number of planes (© ) is several orders of magnitude smaller than then number of pixels (¥ ).