title: Dual-frequency pattern scheme for high-speed 3-D shape measurement.
abstract: A novel dual-frequency pattern is developed which combines a high-frequency sinusoid component with a unit-frequency sinusoid component, where the high-frequency component is used to generate robust phase information, and the unit-frequency component is used to reduce phase unwrapping ambiguities. With our proposed pattern scheme, phase unwrapping can overcome the major shortcomings of conventional spatial phase unwrapping: phase jumping and discontinuities. Compared with conventional temporal phase unwrapped approaches, the proposed pattern scheme can achieve higher quality phase data using a less number of patterns. To process data in real time, we also propose and develop look-up table based fast and accurate algorithms for phase generation and 3-D reconstruction. Those fast algorithms can be applied to our pattern scheme as well as traditional phase measuring profilometry. For a 640 x 480 video stream, we can generate phase data at 1063.8 frames per second and full 3-D coordinate point clouds at 8.3 frames per second. These achievements are 25 and 10 times faster than previously reported studies.
authors.affiliation: Department of Electrical Engineering, University of Kentucky, Lexington, KY 40507, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.forename: Yongchang
authors.initials: Y
authors.lastname: Wang
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Lau
authors.forename: Qi
authors.initials: Q
authors.lastname: Hao
authors.forename: Laurence G
authors.initials: LG
authors.lastname: Hassebrook