基于频率调制二元编码光栅相位测量剖面术

分析传统的频率调制正弦光栅用于3步相移相位测量剖面术时,系统非线性对测量精度的影响,提出采用二元频率调制光栅,提高3步相移相位测量剖面术计算绝对相位测量精度的方法.完成了分别采用传统正弦频率调制光栅投影和基于Floyd-Steinberg二元编码频率调制光栅投影的相移剖面术的绝对相位计算结果对比.结果表明,采用正弦频率调制光栅模板的3步相移算法对系统的非线性敏感,而二元编码频率调制光栅模板既保持了利用单组条纹投影就可计算条纹绝对相位的优点,又不受系统非线性的影响,大大提高了基于频率调制光栅的相移剖面术的测量精度.计算机模拟和实验验证了所提方法的有效性.

Phase measuring profilometry based on binary encoded frequency modulation grating projection

The impact of the system nonlinear on measuring accuracy of three-step phase-shifting measuring profilometry with the traditional sinusoidal frequency modulated grating projection is discussed. A binary encoded sinusoidal frequency modulated grating is used to improve the accuracy of absolute phase calculation in three-step phase-shifting phase measuring algorithm. A comparison of accuracy of absolute phase in phase-shifting measuring profilometry with the traditional frequency modulated grating projection and with binary encoded frequency modulated grating projection based on Floyd-Steinberg is completed as well. These results show that the three-step phase-shifting algorithm based on sinusoidal frequency modulated grating template is sensitive to the nonlinear of the measuring system, however, the application of the binary encoded frequency modulated grating template not only maintains the advantage of calculating absolute phase from a single set of fringe patterns, but also avoids the impact from the nonlinear of the system. The new method greatly improves the measurement accuracy of phase-shifting measuring profilometry based on frequency modulated grating projection. Computer simulation and experiment verified the effectiveness of the proposed method.