在基于条纹投射的物体表面形貌测量中, 温度漂移和振动是造成条纹相位漂移的主要因素。为了稳定条纹相位, 在相位补偿系统 (PCS)中运用峰值检测简化相位提取过程, 发展了一种基于正弦相位调制的干涉条纹相位稳定技术。将光纤缠绕在柱形压电陶瓷 (PZT)上, 向 PZT注入正弦驱动电压实现对干涉条纹相位的正弦相位调制。运用 2×2光纤耦合器分光, 结合马赫-泽德干涉与杨氏干涉结构实现条纹投射。光电探测器检测两端面反射信号形成的迈克尔逊干涉信号, 从中提取环境因素引起的相位漂移, 运用旋转坐标数字机进行快速反正弦计算, 生成的补偿信号与调制信号叠加后共同驱动 PZT, 实现条纹相位稳定。实验结果表明, 条纹相位稳定精度为 5.5 mrad, 较好地消除环境因素引起的相位漂移。

Among methods for measuring the surface profile based on fringe projection, temperature drift and vibration are the main factors which cause phase drift in fringes. To stabilize the fringe phase, peak detection has been used to simplify the process of phase extraction in the phase compensation system (PCS), and a phase stabilization technique based on sinusoidal phase modulation (SPM) has been developed. The optical fiber arms are twined on the cylinder-shaped piezoelectric transition (PZT), and a sinusoidal drive signal has been injected into PZT to realize SPM. The fringe projection can be achieved by combing Mach-Zehnder interference and Young's interference, in which the beams are split by a 2×2 fiber coupler. The photo detector detects Michelson interference signal formed by two reflected beams on two fiber exit faces, and the phase shift is extracted in the phase compensation system. The Coordinated Rotation Digital Computer (CORDIC) is applied for the arcsine calculation, and then a compensation signal is generated and added to drive PZT to achieve a well phase stabilization performance. Experiments show that phase stability in fringes can be measured with a precision up to 5.5 mrad, and the phase shift caused by external disturbances have been well eliminated.