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Generic Nonsinusoidal Phase Error Correction For 3d Shape Measurement Using A Digital Video Projector, Song Zhang, Shing-Tung Yau
Generic Nonsinusoidal Phase Error Correction For 3d Shape Measurement Using A Digital Video Projector, Song Zhang, Shing-Tung Yau
Song Zhang
Structured light system using a digital video projector is increasingly used for a 3-D shape measurement because of its digital nature. However, the nonlinear gamma of the projector causes the projected fringe patterns to be non-sinusoidal, which results in phase error therefore shape measurement error. Previous work showed that, by using a small look-up-table (LUT), this type of phase error can be reduced significantly for a three-step phase-shifting algorithm. In this research, we prove that this type of phase error compensation method is not limited to a three-step phase-shifting algorithm. It is generic for any phase-shifting algorithm. The phase error …
A Fast Three-Step Phase-Shifting Algorithm, Peisen S. Huang, Song Zhang
A Fast Three-Step Phase-Shifting Algorithm, Peisen S. Huang, Song Zhang
Song Zhang
We propose a new three-step phase-shifting algorithm, which is much faster than the traditional three-step algorithm. We achieve the speed advantage by using a simple intensity ratio function to replace the arctangent function in the traditional algorithm. The phase error caused by this new algorithm is compensated for by use of a look-up-table (LUT). Our experimental results show that both the new algorithm and the traditional algorithm generate similar results, but the new algorithm is 3.4 times faster. By implementing this new algorithm in a high-resolution, real-time 3D shape measurement system, we were able to achieve a measurement speed of …
Phase Error Compensation For A 3-D Shape Measurement System Based On The Phase-Shifting Method, Song Zhang, Peisen S. Huang
Phase Error Compensation For A 3-D Shape Measurement System Based On The Phase-Shifting Method, Song Zhang, Peisen S. Huang
Song Zhang
This paper describes a novel phase error compensation method for reducing the measurement error caused by non-sinusoidal waveforms in the phase-shifting method. For 3D shape measurement systems using commercial video projectors, the non-sinusoidal nature of the projected fringe patterns as a result of the nonlinear gamma curve of the projectors causes significant phase measurement error and therefore shape measurement error. The proposed phase error compensation method is based on our finding that the phase error due to the non-sinusoidal waveform of the fringe patterns depends only on the nonlinearity of the projector's gamma curve. Therefore, if the projector's gamma curve …