Phase Estimation in Optical Interferometry

240 ◾ Abhijit Patil, Rajesh Langoju, and Pramod Rastogi

Frame

Grabber

Computer

PZT

Controller

PZT

Object

Camera

Reference

Beam

Hologram

Object Beam

x

z

y

Illumination

Beam

Hologram

Reference

Beam

θ

PZT

PZT

Illumination

Beam

Frame

Grabber

Computer

PZT Controller

PZT Controller

Camera

Object

(a)

(b)

FIGURE 7.1 (a) Schematic of holographic interferometry. (b) Schematic of holo-

graphic moiré.

Signal-Processing Methods in Phase-Shifting Interferometry ◾ 241

7.3 LINEAR PHASE STEP ESTIMATION METHODS

Let us rst start the discussion of linear phase step estimation methods