三频多周期模拟编码光三维测量方法研究

发布时间：2018-01-18 11:01

本文关键词：三频多周期模拟编码光三维测量方法研究　出处：《哈尔滨理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：三维测量技术因其智能化、便捷化和快速测量等特点,在工业生产、医疗、航天等诸多领域起到不可替代的作用。其中以相移法为代表的模拟编码光测量方法因具有高分辨率和高采样密度,成为三维测量领域中最具发展前景的测量方法。然而,在应用单周期模拟码进行测量时,要求相邻像素间具有高光强差,否则会导致抗干扰能力低的问题,而采用多周期模拟码又会带来多点相位值相同的问题。因此,本文以提高模拟编码光抗干扰能力以及保证解相后相位无误差展开为目的,提出了三频多周期模拟编码光三维测量方法,包括系统联合gamma值的标定和校正效果明显的gamma非线性校正。在现有技术多步余弦相移法的基础上,采用多周期模拟码以增强相邻像素之间光强差,以减小量化误差,提高抗干扰能力;针对采用多周期相移编码进行测量时,相位取值存在二义性的问题,建立了三频模拟编码光相位展开模型,分析推导出数学公式,并通过理论分析,确定了本文中的相位展开方法对包裹相位的误差容限,推导出三频模拟编码光组合的等效周期,给出组成编码光的最优频率组合;最后,对本文构建的三维测量系统联合gamma值进行了标定,并对非线性误差进行了校正,将gamma标定技术结合三频多周期余弦相移法,以及三频相位展开方法进行了三维测量实验,实验包括联合gamma标定与校正实验,本文三维测量方法对平面和复杂表面测量实验,本文三维测量方法与双频法、外差法的对比实验等,依据各实验得出的测量结果,对本文测量方法做出了评价。通过理论分析和实验结果表明,本文测量方法与双频法相比,测量平均值提高了70.6%,对相位的求解准确度更高;与外差法在相同的编码条纹周期组合下进行测量,平均均方差提高68.24%,展开相位残差曲线变化平稳,展开准确度更高,并从原理上避免了相位误差的扩大而导致的跳变误差。本文研究的三频相位展开方法算法简单、展开范围大、抗干扰能力更强、能够在误差容限内无误差展开,为模拟编码光三维测量提供了理论和实验基础。
[Abstract]:3D measurement technology, due to its intelligent, convenient and rapid measurement characteristics, in industrial production, medical treatment. Space and many other fields play an irreplaceable role. Among them, the analog coded optical measurement method, represented by phase-shift method, has high resolution and high sampling density. It has become the most promising measurement method in the field of three-dimensional measurement. However, in the application of single-period analog code, high intensity difference between adjacent pixels is required, otherwise, it will lead to the problem of low anti-jamming ability. The use of multi-period analog code will lead to the same multi-point phase value. Therefore, the purpose of this paper is to improve the anti-jamming ability of analog coding light and to ensure the phase error free expansion after phase resolution. A three-frequency and multi-period analog coded optical 3D measurement method is proposed. It includes the calibration of the system combined with the gamma value and the gamma nonlinear correction which has obvious effect. Based on the existing techniques of multi-step cosine phase shift method. Multi-period analog code is used to enhance the intensity difference between adjacent pixels to reduce the quantization error and improve the anti-jamming ability. In order to solve the problem of ambiguity in the measurement of multi-period phase-shift coding, a three-frequency analog coded optical phase unwrapping model is established, the mathematical formula is derived, and the theoretical analysis is carried out. The error tolerance of the phase unwrapping method to the envelope phase is determined, the equivalent period of the three-frequency analog coded light combination is derived, and the optimal frequency combination of the coded light is given. Finally, the combined gamma value of the 3D measurement system constructed in this paper is calibrated, and the nonlinear error is corrected. The gamma calibration technique is combined with the three-frequency multi-period cosine phase shift method. The three-frequency phase unwrapping method is used to carry out the three-dimensional measurement experiment, which includes the gamma calibration and correction experiment. The three-dimensional measurement method is used to measure the plane and complex surface. According to the measurement results obtained from each experiment, the measurement method of this paper is evaluated. The theoretical analysis and experimental results show that the three dimensional measurement method is compared with the dual-frequency method and the heterodyne method. Compared with the dual-frequency method, the average value of this method is 70.6 higher than that of the dual-frequency method, and the accuracy of the phase solution is higher than that of the dual-frequency method. With the same coding fringe cycle combination, the mean mean square deviation (RMS) is increased by 68.24%, the unfolded phase residual curve changes steadily, and the expansion accuracy is higher. In principle, the jump error caused by the expansion of phase error is avoided. The three-frequency phase unwrapping method studied in this paper has the advantages of simple algorithm, large expansion range, stronger anti-jamming ability, and can be expanded without error within the error tolerance. It provides theoretical and experimental basis for analog coded light 3D measurement.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O439

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