基于单帧采集的相移测量轮廓术

Phase Shifting Profilometry Based on Single-Shot Acquisition

提出了一种基于单帧采集的相移测量轮廓术(Phase Shift Profilometry,PSP),该方法保留了传统相移测量轮廓术的相移特性和高精度的特点,同时又能在实时测量的时候仅采集单帧变形条纹。在传统的N步相移测量轮廓术中,需要投影N(N>2)帧相移正弦光栅,并采集N帧变形相移条纹,而且随着N值增大测量精度更高。所提方法只需要投影一帧正弦光栅,并采集一帧变形条纹,同时对相移步数的提高可以让测量精度随之变高,而且在静态测量和实时三维测量中都可以保证单帧采集的特征。此外,该方法的数学模型与传统PSP的相比更加简洁,得到的包裹相位仅与物体本身的高度有关,无需对参考平面和被测物体分别进行相位运算和解调。相比于其他单帧测量方法精度更高,有效地避免了对变形条纹频谱直接滤波带来的频谱缺失,或者是其他基于PSP的实时测量的颜色混叠、动态范围受限的问题。仿真和实验结果表明了该方法的可行性和有效性。

A new phase shifting profilometry based on single-shot acquisition is proposed.This method retains the phase shifting characteristics and high accuracy of traditional phase shifting profilometry(PSP),and can only captures one deformedpattern during real-time measurement.In traditional phase shifting profilometry,N(N>2)framesof the phase shifting sinusoidal gratingsare projected and N frames of the phase shifting deformedpatterns are captured,and the measurement accuracy is higher as N value increases.The method proposed in this paper only needs to project one sinusoidal grating and captureone deformed pattern while measuring,and the measurement accuracy can be improved by increasing the number of phase shifting,and the characteristics of single-shot acquisition can be guaranteed in both static measurement and real-time 3D measurement.In addition,the mathematical model of this method is more concise than that of the traditional PSP,and the wrapped phase obtained is only related to the height of the object itself,without phase calculation and demodulation of the reference plane and the object to be measured.Compared with other single-shot measurement methods,the accuracy is higher,and effectively avoids the spectrum loss caused by direct filtering of the deformed pattern’s spectrum,or the problems of color aliasing and limited dynamic range caused by other real-time measurements based on PSP.Simulation and experimental results show the feasibility and effectiveness of the proposed method.