Crossed fringe pattern - a novel tool for 3D metrology

Phase-measuring deflectometry measures the two components of the local surface gradients via displaying a sequence of two orthogonal sinusoidal grid patterns separately. The necessity of a sequential process can be avoided by a crossed fringe pattern. With this pattern, we will demonstrate single-shot (real-time) deflectometry. Furthermore, we will demonstrate the possibility of phase shifting with this pattern. An N-phase-shift is possible for BOTH components (x and y) with only N exposures, instead of 2N exposures, which are necessary for classic deflectometry. An interesting option of the new method is: The crossed fringe pattern can be printed on a slide and the phase shifting can be realized by just performing a (single-direction) mechanical shift of the slide. We will demonstrate this novel phase-shifting technique for deflectometry, as well as for structured-illumination microscopy, and discuss the potentials and the limits of the novel method.