Moire

when a fine pattern in the subject (such as the weave in a fabric or very close, parallel lines in architecture) matches the pattern of the imaging chip. When two patterns meet, often a third, new pattern is created.

moire topography

A method of three-dimensional morphometry in which contour maps are produced from the overlapping interference fringes created when an object is illuminated by beams of coherent light issuing from two different point sources.