光反馈自混合干涉信号噪声处理及位移测量算法的研究

发布时间：2018-06-08 03:35

本文选题：位移测量 + 光反馈自混合干涉(OFSMI)　；参考：《郑州大学》2015年硕士论文

【摘要】：激光器发出一束光线,照射在外部物体上,这束光经外部物体吸收、反射、散射后,一部分光又返回到激光器的谐振腔内,与谐振腔内的激光进行混合,从而调制了激光器的输出功率,这种现象就叫做光反馈自混合干涉(Optical Feedback Self-Mixing Interference,简称OFSMI)。相较于传统的干涉系统,光反馈自混合干涉技术构成的系统具有结构简单紧凑、易准直等优点。光反馈自混合干涉系统多用于物理量传感测量,这是由于OFSMI信号中携带着外部物体的诸多信息。目前,光反馈自混合干涉系统应用于机械量如位移、振动、距离、轮廓等的传感测量。由于OFSMI测量系统具有高分辨率、高精度等优点,所以光反馈自混合干涉技术在传感测量领域具有广阔的研究前景。由实验中得到的OFSMI信号中带有大量的噪声,所以本文重点研究了光反馈自混合干涉信号噪声处理的两种方法:1、基于分数阶Fourier变换LMS自适应滤波算法;2、基于噪声辅助经验模式分解(EEMD)的阈值处理算法。通过仿真实验,OFSMI信号的信噪比有了较大的提高。然后,本文介绍了光反馈自混合干涉的理论分析模型,分析了光反馈水平因子C对自混合干涉信号的影响,并且深入研究了在高光反馈条件下,外部物体做周期运动时自混合干涉条纹丢失现象,得出反馈水平因子C和半个周期内条纹丢失数目m之间的规律,并设计基于条纹丢失补偿的自混合干涉位移测量算法,以提高位移测量精度。最后,给出了本文的结论,提出了光反馈自混合干涉信号在噪声处理方面及位移测量领域有待进一步深入研究探索的问题。
[Abstract]:The laser emits a beam of light on an external object, which is absorbed, reflected, and scattered by the external object, and some of the light returns to the resonator of the laser and is mixed with the laser in the resonator. Thus the output power of the laser is modulated. This phenomenon is called optical feedback self-Mixing interference. Compared with the traditional interference system, the optical feedback self-mixing interference system has the advantages of simple and compact structure, easy collimation and so on. Optical feedback self-mixing interference system is widely used in physical quantity sensing measurement because OFSMI signals carry a lot of information about external objects. At present, optical feedback self-mixing interferometry system is applied to the sensing measurement of mechanical parameters such as displacement, vibration, distance, profile, etc. Because the OFSMI measurement system has the advantages of high resolution and high precision, the optical feedback self-mixing interferometry has a broad research prospect in the field of sensor measurement. The OFSMI signal obtained from the experiment has a lot of noise. Therefore, this paper focuses on two noise processing methods of optical feedback self-mixing interference signal: 1: 1, LMS adaptive filtering algorithm based on fractional Fourier transform and EEMD-based noise assisted empirical mode decomposition. The signal-to-noise ratio of OFSMI signal is greatly improved by simulation. Then, this paper introduces the theoretical analysis model of optical feedback self-mixing interference, analyzes the influence of optical feedback level factor C on the self-mixing interference signal, and deeply studies the influence of the optical feedback level factor C on the self-mixing interference signal under the condition of high-light feedback. The phenomenon of self-mixing interference fringe loss is obtained when the external object is in periodic motion. The law between the feedback level factor C and the number of fringe loss m in half a period is obtained, and a self-mixing interferometric displacement measurement algorithm based on fringe loss compensation is designed. In order to improve the accuracy of displacement measurement. Finally, the conclusion of this paper is given, and the problems of optical feedback self-mixing interference signal in noise processing and displacement measurement are put forward.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248

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