What is a "phase map"? I am doing some reading on Structured Light 3D Scanners using digital fringe projection, where a projector shines light (e.g. sinusoidal patterns) onto an object, a camera takes some pictures, and some software uses them to extract a 3D model of the object. The papers I have been reading talk about acquiring a "phase map" of the surface and comparing it to a "reference phase map". None of them seem to actually define what this means, and searching on Google seems to just give links to papers. Here is an example: http://www.cadanda.com/V2No6_04.pdf [Broken] (ctrl-F "phase map" will give plenty of results) Can anyone explain in relatively simple terms? I have quite a good understanding of time/frequency domain, Fourier Transforms, etc. but have never heard this term before.