Single-shot 3-D sensing of micro-meter height by multi-wavelength parallel phase-shifting digital holography

Abstract

We propose a single-shot three-dimensional sensing technique being capable of achieving measurement of a micro-meter height by multi-wavelength parallel phase-shifting digital holography. In the proposed technique, we use the two-wavelength phase unwrapping method to expand measurement range in the height direction to measure a step of more than half a wavelength in height. To confirm the effectiveness of the proposed technique, we conducted an optical experiment in which we used the object with abrupt step of 1.90 m. The experimental result indicated that the height of the object was 1.85 m. Thus, we experimentally verified the proposed technique.