Design and evaluation of phase mask for high-speed fringe projection

In the past 30 years, research on fringe projection technology for shape measurement has made remarkable progress. Numerous approaches have been proposed for fringe projection, data acquisition, fringe analysis, phase unwrapping and calibration with the goal of increasing measurement accuracy and speed. In particular, the temporal phase unwrapping method of inverse exponential sequence can provide independent high signal-to-noise ratio (SNR) data for each camera pixel, preventing unwrapping error propagation across the phase maps. This algorithm is used for high-precision phase unwrapping but requires a large number of fringe projections to produce a single shape measurement, which makes real-time dynamic measurements challenging. As a result, projection speed has become a key requirement for high-speed and high-precision fringe projection technology. [Continues.]