Patent ID: 7495773

Claim:
An interferometric in situ calibration method for mapping the correspondence between pixel coordinates and part locations where measurements of the part are to be taken, said interferometric in situ calibration method comprising the steps of: mounting a part to be tested for precise movement in one to six degrees of freedom in three-dimensional space within an interferometer cavity; precisely moving the part prior to its actual measurement in at least one of the six possible degrees of freedom between a base position and at least one other position; generating maps of the difference in phase between individual pixels and their corresponding part position as measured between the base position and all other positions; calculating a map of u, the angular direction from points on the part to their corresponding pixel; determining a map of sin u from the map of u; determining from the map of sin u the lateral location to each point on the part; and correlating each pixel coordinate with its corresponding lateral location of each point on the part.