Method for correcting fringe order error in white light phase-shifting interferometer

Abstract

The present invention relates to a method of compensating a fringe order error in white-light phase-shifting interferometry, including: an interference signal acquisition step, an index determination step, and a real position calculation step. The interference signal acquisition step includes acquiring at least two color interference signals, using a color camera, from among a red interference signal, a green interference signal, and a blue interference signal. The index determination step includes determining a position where a phase difference between the at least two interference signals reaches a minimum value as an index of the zero order interference signal position. The real position calculation step includes determining, as a zero order interference signal measured position, a position corresponding to the index of the zero order interference signal position from among positions where interference signals are measured from black-and-white interference signals acquired through a black-and-white camera, and calculating a zero interference signal real position where the intensity of light is a maximum value by adding or subtracting a phase value of the zero order interference signal measured position to or from the zero order interference signal measured position.

Description

technical field [0001] The present invention relates to a method for correcting the error of the fringe order in a white light phase-shift interferometer, and more particularly, to a method for correcting the error of the fringe order in a white light phase-shift interferometer, wherein when determining the white light phase shift The order of the interference signal acquired by the interferometer prevents errors due to phase ambiguity. Background technique [0002] An interferometer is a device that emits light onto the surface of an object to be scanned and a reference plane, generates an interference signal based on two light waves reflected from the object and passes through the object, and measures and analyzes the interference signal, thus obtaining information about the Information about the surface shape of an object. [0003] Such interferometers are widely used in industry due to their ability to easily determine the shape of the object to be scanned. In particul...

AI Technical Summary

Problems solved by technology

[0008] In this state, the wrong position h2 of the zero-order interference signal calculated in this state has a phase difference of 2π from the real position h0 of the zero-order interference signal, and thus leads to an error in measuring the shape of the object

Images