Patent ID: 8692999

Claim:
A method of minimizing fringe print-through in a phase-shifting interferometer, comprising the steps of: (a) determining multiple transfer functions of pixels in the phase-shifting interferometer; (b) computing a crosstalk term for each transfer function, and (c) displaying, to a user, a phase-difference map using the crosstalk terms computed in step (b), wherein computing crosstalk terms in step (b) includes computing an N-dimensional vector, where N corresponds to the number of transfer functions, and the N-dimensional vector is obtained by minimizing a variance of a modulation function, and wherein N has a value of four, and the modulation function, defined as gamma, includes the following relationship: gamma=2*sqrt(( d 1 −n 1Cancel)^2+( n 1 −d 1Cancel)^2))/intensity; in which: n1=y1−y3; d1=y4−y2; d1Cancel=a(1)*y2+a(2)*y4; where d1Cancel is a cancellation term, and a is a vector of the coefficients, y1, y2, y3 and y4; n 1Cancel= a (3)* y 1 +a (4)* y 3; where n1Cancel is a cancellation term, and a is a vector of the coefficients, y1, y2, y3 and y4; intensity= y 1 +y 2 +y 3 +y 4; and y1, y2, and y4 are four interferogram images.