Interferometric Dynamic Measurement: Techniques Based on High-Speed Imaging or a Single Photodetector

Table 1

Comparison of spatial-carrier and temporal-carrier-based techniques in interferometry.

Factors	Spatial-carrier-based technology	Temporal-carrier-based technology
Processing domain	𝑥- and 𝑦-axis	𝑡-axis
Dimension	2-D	1-D
Reflectivity	Affected by nonuniform reflectivity	Not affected
Height step	Affected by height step of test objects	Not affected
Shape	Affected by irregular shape of surface	Not affected
Retrieved phase map quality	Poor and affected by speckle noise when laser is used	Much better than spatial carrier as the process is 1-D along time axis.
Measurement range in temporal domain	Determined by Nyquist sampling theorem	Affected by temporal carrier and much less measurement range than spatial carrier