Effect of detector displacement in confocal imaging systems

Confocal imaging systems rely on the use of an accurately positioned axial point detector. We discuss in this paper the effects on the various imaging modes of using a misaligned pinhole. We pay particular attention to the form of the transfer function and the depth discrimination property. A simple model of a thick edge type object is introduced, and it is found that in certain cases a degree of detector offset may be used to advantage in determining the position of the edge.