【作者】 罗印龙；

【导师】 吕晓旭；

【作者基本信息】 昆明理工大学 ， 物理电子， 2005， 硕士

【摘要】 位相测量是在20世纪80年代得到发展和应用以提高光学测量精度的技术。它可获得被测区域内全场的相位数据,真正实现了光学相位的全场测量。相移位相测量方法是一种高精度位相测量方法,当视场内少于一个条纹时,这种方法仍然有效。实现相移位相测量方法途径的实质也是相位调制,而相移器是实现相位调制的关键部件,其相移精度是影响位相测量精度的重要因素之一。因此,相移器的精确标定或校正在位相测量中具有十分重要的意义。 本文以PZT作为移相执行器,利用LabVIEW及相应的数据采集卡,结合在VC开发平台上编写的图像采集处理程序,研制了一套相移位相测量系统。该系统采用单探测器作为标定信号转换元件,对条纹图的空间分布没有任何要求,且具有在同一光路中实现相移与标定的优点。 针对干涉仪工作时因外界扰动,难以获得准确相移量的情况,本文提出了一种基于数字相关实时获得相移前后干涉图间相移量的方法,保证了在存在外界干扰的情况下也能采集到具有高准确度相移量的干涉图。 在所研究的相移位相测量系统上,为有效解决PZT非线性对移相精度的影响,五步相移技术中,提出了利用PZT的位移—电压特性曲线实现自动校正相移器非线性的新方法。 同时,还研究出了用PZT作为相移器时,克服PZT的各种特性对相移精度影响的有效措施。针对压电陶瓷相移器存在的蠕变特性,采用线性变化的驱动电压,使相移器由于自身的蠕变而产生连续相移;而对迟滞特性,则采用了回零控制法,使移相与标定过程具有很好的一致性。 通过系统的比较研究和在物体三维持形貌实际测量及同轴相移无透镜傅立叶变换数字全息中的实际应用,证明了本文研究的相移系统和方法可以达到很高的测量精度,在相位测量技术中具有广泛的实用价值。更多还原

【Abstract】 Phase measurement technique appeared in 1980s, which greatly improved the accuracy of optical metrology. With the data obtained in the testing field at the same time, the optical phase of full field testing is realized in deed associated with this technique. Phase-shifting is one of high accurate phase measurement technique. With less than one fringe in the field, the measurement also can be carried out efficiently by this way. The most common way to vary the phase is to apply phase modulation. The phase-shifter is the key component, whose accuracy directly effects the accuracy of phase measurement. Therefore the calibration of phase shifter is very important for the phase measurement.The phase-shifting system is developed on LabVIEW and PC1200DAQ combined with image capture software in VC. The calibration of this system with single detector can be applied to extensive situation of interferograms. Meanwhile, phase-shifting and calibration on the same optical setup is another advantage compared with other methods.Furthermore, in the circumstance of vibration and air turbulence, the expected value of phase shifting is hard to obtained. A novel method, which evaluates real-time phase variation between the two fringes based on digital correlation is presented. Interferograms are captured with accurate phase-shifting value even if the external turbulence exists.Based on researched phase-shifting system, a new method of five-step phase-shifting which can eliminate influence of PZT nolinearity on the precision of shifting by the relationship between micro-displacement and applied voltage is described.Meanwhile, the effective ways are introduced to decrease the influence of the characteristics of the PZT. For the creep, the continuous voltage is applied to the shifter, and continuous phase-shifting is obtained with creep effect itself. Moreover the zero-returned method is introduced to overcome the hysteresis, the coherent between phase-shifting and calibration is achieved.Finally, the system was applied to three-dimension profilometry and online phase-shifting lensless Fourier digital holography, the experimental results show the that phase-shifting system and calibration method developed in this paper can reach high accuracy and has widely application prospects in phase measurement technology..更多还原