[Paper Review] One shot profilometry using iterative two-step temporal phase-unwrapping

Guangliang Du, Minmin Wang+5 more|arXiv (Cornell University)|May 19, 2016

Optical measurement and interference techniques3 citations

TL;DR

This paper proposes a one-shot 3D profilometry method combining composite fringe projection with an iterative two-step temporal phase unwrapping algorithm, enabling fast, high-accuracy shape measurement in a single capture. By leveraging a single composite fringe pattern containing four frequency components and iteratively refining phase unwrapping, the method achieves improved precision over prior single-shot approaches while maintaining speed.

ABSTRACT

This paper reviews two techniques that have been recently published for 3D profilometry and proposes one shot profilometry using iterative two-step temporal phase-unwrapping by combining the composite fringe projection and the iterative two-step temporal phase unwrapping algorithm. In temporal phase unwrapping, many images with different frequency fringe pattern are needed to project which would take much time. In order to solve this problem, Ochoa proposed a phase unwrapping algorithm based on phase partitions using a composite fringe, which only needs projecting one composite fringe pattern with four kinds of frequency information to complete the process of 3D profilometry. However, we found that the fringe order determined through the construction of phase partitions tended to be imprecise. Recently, we proposed an iterative two-step temporal phase unwrapping algorithm, which can achieve high sensitivity and high precision shape measurement. But it needs multiple frames of fringe images which would take much time. In order to take into account both the speed and accuracy of 3D shape measurement, we get a new, and more accurate unwrapping method based on composite fringe pattern by combining these two techniques. This method not only retains the speed advantage of Ochoa's algorithm, but also greatly improves its measurement accuracy. Finally, the experimental evaluation is conducted to prove the validity of the proposed method, and the experimental results show that this method is feasible.

Motivation & Objective

• To address the trade-off between measurement speed and accuracy in 3D profilometry.
• To overcome the imprecise fringe order determination in Ochoa's phase partition-based single-shot method.
• To integrate the high-precision iterative two-step temporal unwrapping algorithm with composite fringe projection for one-shot operation.
• To achieve fast, accurate 3D shape reconstruction without requiring multiple phase-shifted frames.

Proposed method

• A single composite fringe pattern containing four different frequency components is projected onto the object surface.
• The phase information from the composite pattern is extracted using temporal phase unwrapping techniques.
• An iterative two-step temporal phase unwrapping algorithm is applied to resolve phase ambiguities with high precision.
• The algorithm iteratively refines the unwrapped phase map by minimizing phase discontinuities and improving accuracy.
• The method combines the speed of single-shot acquisition with the accuracy of multi-frame unwrapping by using frequency multiplexing in a single pattern.
• Phase unwrapping is performed using a partition-based approach on the composite fringe, enhanced by iterative refinement to reduce errors.

Experimental results

Research questions

• RQ1 Can a single-shot 3D profilometry system achieve high measurement accuracy comparable to multi-frame temporal phase unwrapping methods?
• RQ2 How can the phase unwrapping accuracy of Ochoa's composite fringe method be improved without increasing acquisition time?
• RQ3 To what extent does iterative refinement enhance phase unwrapping precision in a single composite fringe pattern?
• RQ4 Can the combination of composite fringe projection and iterative two-step unwrapping enable real-time, high-accuracy 3D shape measurement?
• RQ5 What is the impact of frequency multiplexing on phase ambiguity resolution in one-shot profilometry?

Key findings

• The proposed method achieves high-precision 3D shape measurement using only a single fringe pattern projection.
• The iterative two-step unwrapping algorithm significantly improves phase unwrapping accuracy compared to conventional single-shot methods.
• The method retains the speed advantage of one-shot acquisition while overcoming the imprecise fringe order estimation in prior composite fringe techniques.
• Experimental results validate the feasibility and effectiveness of the proposed approach in practical 3D profilometry applications.
• The integration of composite fringe projection with iterative unwrapping enables robust phase reconstruction with reduced errors in complex surface measurements.