ABSTRACT
Before we start dealing with images as discrete measurements, we critically look at how they are measured. The typical aperture shape in today’s image acquisition equipment is square, as it is easy to fabricate on a detector chip. Koenderink [17] already noted in the 1980s that such a representation gives rise to “spurious resolution,” the appearance of nonexisting edges and comers. The effect appears clearly when we zoom in to pixel level (Figure 17.1): The face of the author certainly has no square comers all over and sharp edge discontinuities. So what is the shape of the optimal aperture?
