3D shape measurements with high-speed fringe projection and temporal phase unwrapping

Abstract

The abilities to increase precision of surgical procedures by tracking real-time motions, accurately measuring the mechanical properties of complex 3D geometries, and tracking deformations of components over time, among many other applications, depend on the availability of robust, high-speed, full-field-of-view, 3D shape measurement systems. In this paper, we present advances in our development of a high-speed 3D shape measurement system based on fringe projection. The system consists of a high-speed projector, with speeds up to 20,000 frames per second, that is integrated with a CCD camera to provide full-field-of-view information. By using high-speed projection of sinusoidal fringe patterns with varying spatial densities together with temporal phase unwrapping algorithms that we are developing, we are able to compute and display unwrapped phase maps at video rates, which enable the capability to perform absolute shape measurements of components. We present representative results obtained with our system as we have applied it to art conservation and to biomedical imaging. Results validate system capabilities as a high-speed method of dynamically gathering, analyzing, and displaying shape information.