Changes

== Phase Shifting Technique ==

== Phase Shifting Technique ==

As noted in the introduction, the first phase-shifting algorithms were designed in the 1960's by Carre, Rowley and Harmon.  The essence of the phase shifting algorithm lies in the ability to gather the necessary phase information from (theoretically) three to (more realistically) five interference patterns, called frames, so that a nearly complete image may be rendered of the surface in question.

As noted in the introduction, the first phase-shifting algorithms were designed in the 1960's by Carre, Rowley and Harmon.  The essence of the phase shifting algorithm lies in the ability to gather the necessary phase information from (theoretically) three to (more realistically) five interference patterns, called frames, so that a nearly complete image may be rendered of the surface in question.

In recent years combinations of spatial and temporal methods have been combined and thus form a subcategory of the phase-shifting method, known as "self calibrating [sic] spatio-temporal algroithms."  Among these methods are the Fourier Method, the Lissajou ellipse fitting method, the interferogram correlation method and others.  Each of these have their high points and low points, mostly stemming from either the type of surface they best work for or the the number of frames required.

In recent years combinations of spatial and temporal methods have been combined and thus form a subcategory of the phase-shifting method, known as "self calibrating [sic] spatio-temporal algroithms."  Among these methods are the Fourier Method, the Lissajou ellipse fitting method, the interferogram correlation method and others.  Each of these have their high points and low points, mostly stemming from either the type of surface they best work for or the the number of frames required.  

* requires three phase shifted fringe patterns

* requires three phase shifted fringe patterns