Noise Reduction in Coherence Scanning Interferometry for Surface Topography Measurement

Coherence scanning interferometry is one of the most accurate surface measuring technologies, and it is increasingly applied to challenging surface structures, such as additive manufactured parts and transparent films, directly in environments that resemble production areas more than metrology labs. Environmental disturbances may further compromise measurement accuracy. Data acquisition strategies to reduce measurement noise in coherence scanning interferometry include averaging a sequence of repeated topography measurements or increasing the sampling frequency of the fringe signal during a single data acquisition—sometimes referred to as oversampling. In this paper, we improve the understanding of the mechanisms of the two noise reduction methods and compare their effects on surface topography measurement in the presence of environment-induced vibration. The results provide guidance for good practice in the reduction of uncertainty in surface measurement for a wide range of applications.