Shape measurement using one frame projected sawtooth fringe pattern

• Main Authors: Chen, Lujie, Quan, Chenggen, Tay, Cho Jui, Fu, Yu
• Other Authors: Temasek Laboratories
• Format: Article
• Language: English
• Published: 2011
• Subjects: DRNTU::Science::Physics::Optics and light
• Online Access: https://hdl.handle.net/10356/91209; http://hdl.handle.net/10220/6704
• Institution: Nanyang Technological University

Fringe projection technique is a non-contact, full field shape measurement method. The object depth information is recorded as sinusoidal or square wave fringe patterns. The phase-shifting technique or Fourier transform method can be used to extract wrapped phase data and a continuous phase distribution can be retrieved by a phase unwrapping process. In this paper, a shape measurement method using one frame projected sawtooth fringe pattern is proposed. A computer-generated sawtooth pattern is projected by a programmable liquid crystal display (LCD) projector. The deformed sawtooth pattern encoding object shape is converted to a wrapped phase map without using phase shifting or Fourier transform and a continuous phase distribution is retrieved by a quality-guided phase unwrapping algorithm. A special phase quality map, capable of detecting invalid shadowed phase data, is proposed to facilitate the unwrapping process.