"High-speed three-dimensional absolute shape measurement with three binary patterns," (2020)

J.-S. Hyun and S. Zhang, "High-speed three-dimensional absolute shape measurement with three binary patterns," Optical Engineering, 59(2), 024104 (2020); doi: 10.1117/1.OE.59.2.024104

Abstract

Reducing the number of structured patterns for three-dimensional (3D) reconstruction is of great importance for high-speed 3D shape measurement. This paper presents a method that reconstructs absolute 3D shape using three binary patterns: one DC, one low-frequency and one high-frequency fringe pattern. The procedures are: 1) take the difference between the sinusoidal fringe patterns and the DC pattern;  2) apply Hilbert transform to the difference images to generate two phase maps; 3) employ the geometric constraint based phase unwrapping method to unwrap the low-frequency phase map; 4) unwrap the high-frequency phase map using the unwrapped low-frequency phase map; and 5) reconstruct 3D shape.  We developed a prototype system that can capture 2D images at 6,000 Hz, achieving 2,000 Hz 3D shape measurement speed.