Moiré interferometry.

The generalized principle of moiré interferometry is explained theoretically. As a result it becomes clear that the application of incoherent moiré techniques to a two-beam interferometer enables measurement of wavefront deformation that is given by an object at two different times, but it cannot reduce distortion in a viewing system. Experimental results of electronic moire interferometry are presented. They show that the principle is correct, the electronic techniques are superior to photography for the moiré interferometry, and a standard video system shows satisfactory performance for measurement of a transparent-type phase object.