ABSTRACT
Interferometric techniques have found widespread use in three-dimensional (3D) profilometry. When two coherent waves of wavelength λ are brought together such that they have traversed a relative optical path difference Δx, the intensity obtained is given by [1]
I I I S xDC M= + cos( )∆
where S is introduced as a sensitivity parameter I is the measured intensity IDC is the constant component of the intensity IM is the modulation depth of the interference term
In a conventional Twyman-Green interferometer [2] (see Figure 8.1a), the laser beam is split and the object beam directed to the test object with the
CONTENTS
8.1 Introduction ................................................................................................ 219 8.2 Coherent Fringe Projection Systems: Optical Setups and
Characteristics ............................................................................................ 221 8.2.1 Twin-Fiber-Based Coherent Fringe Projection .......................... 221 8.2.2 Diffraction Grating Fringe Projection .........................................222 8.2.3 Sensitivity and Effective Wavelength .........................................223
