基于组合二值条纹离焦投影的三维面形测量

3D Shape Measurement Based on Defocused Projection of Combined Binary Fringe

二值条纹离焦投影技术很好地克服了条纹投影三维测量技术中的非线性影响,有效抑制了投影设备Gamma效应带来的误差。多频条纹二值离焦投影结合时间相位展开算法,是常用的复杂物体三维测量方法。该方法在使用中要保证多个频率二值条纹离焦获得大致相当的正弦性品质,投影时不同频率条纹对应的离焦量不一样,不利于其广泛使用。分析了不同二值化方法条纹的离焦量与正弦性品质之间的关系,提出了采用不同二值化方法生成待投影的不同频率条纹,在同一固定离焦量下进行三维面形测量的方法。提出的组合二值条纹方法与单一二值条纹方法的仿真和实验测量结果表明,该方法能保证测量精度,且实际使用时不同频率条纹的离焦量固定不变,方便易行。

The defocused projection of binary fringe overcomes the nonlinear effect of fringe projection on 3D shape measurement,and effectively suppresses the error caused by Gamma effect of the used projector. Multi-frequency binary defocused fringe projection combined with temporal phase unwrapping is a common 3D shape measurement method for complex objects. In its application,it is necessary to ensure that multiple frequency binary fringes can get approximately the same sinusoidal quality,and the defocusing amounts of different frequency fringes are different,which is not conducive to its wide use. In this paper,the relationship between the defocused amount and the sinusoidal quality of the fringe with different binarization methods is analyzed,and a method of 3D shape measurement is proposed by using different binarization methods with the same fixed defocusing amount while projecting the different frequency fringes. The comparison,simulation and experimental results of the combined binary fringe method in this paper and the single frequency binary fringe method show that the combined binary fringe method proposed in this paper has higher accuracy and the defocusing amount of the fringe at different frequencies is fixed in practice,which is convenient and easy to operate.