Phase retrieval for high-speed 3D measurement using binary patterns with projector defocusing

Recent digital technology allows binary patterns to be projected with a very high speed, which shows great potential for high-speed 3D measurement. However, how to retrieve an accurate phase with an even faster speed is still challenging. In this paper, an accurate and efficient phase retrieval technique is presented, which combines a Hilbert three-step phaseshifting algorithm with a ternary Gray code-based phase unwrapping method. The Hilbert three-step algorithm uses three squared binary patterns, which can calculate an accurate phase even under a slight defocusing level. The ternary Gray code-based method uses four binary patterns, which can unwrap a phase with a large number of fringe periods. Both simulations and experiments have validated its accuracy and efficiency.NRF (Natl Research Foundation, S’pore)Published versio