提出一种基于三步非定步相移的三维面形测量方法。首先将投影仪投出的光栅进行预校正，保证投到参考面的条纹为标准的正弦条纹。测量时，由投影仪投影三幅等相移量的光栅到待测物体表面，CCD相机对应采集三帧变形条纹图，由相位计算模型提取相位。最后通过高度映射公式恢复待测物体的三维面形。该方法有较好的抗噪性能，在噪声较大情况下，仍能进行测量，为动态在线测量奠定了基础。模拟及初步实验均验证了该方法的可行性。%A method to measure the three-dimensional (3D) surface figure based on three step phase-shifting is proposed. Firstly, the grating projected by a projector is pre-corrected to assure standard sinusoidal fringe projected on the reference surface. Secondly, three frames of grating with same phase-shifting are projected on the surface of the tested object by a projector during measurement. Three frames of deformation fringe patterns are captured by a CCD camera and the phase is extracted from a phase calculation model. Finally, the 3D surface figure of the tested object can be reconstructed by height mapping formula. The method has stronger anti-noise ability, measurement process can still be performed in large noise environment, which lay a foundation for dynamic on-line measurement. The feasibility of this method is verified by simulations and initial experiments.
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