基于三角波条纹离焦的三维面形测量方法研究

发布时间：2018-01-14 01:18

本文关键词：基于三角波条纹离焦的三维面形测量方法研究　出处：《南昌航空大学》2017年硕士论文　论文类型：学位论文

【摘要】：基于光学的三维面形测量技术具有非接触、测量精度较高、可实现在线检测等优点,在航空航天、汽车制造、工业化生产等诸多方面得到应用。然而,目前常用的测量系统中存在的Gamma效应严重影响了测量精度,而且无法对镜面物体进行有效的测量。如何有效的克服Gamma效应,进一步提高测量精度,进而实现对镜面物体的三维面形测量在现代检测中有着重要意义。传统的方法中,采用二进制条纹离焦测量时,一般采用调节投影设备主动离焦或者较远离焦距离进行自动离焦。以上两种离焦方法,离焦程度都相对较深,降低了投影条纹强度,使得相位获取准确率降低,从而影响了测量精度;采用正弦条纹进行测量时,由于投影仪的Gamma效应导致投影条纹中有相当多的高次谐波,降低了条纹质量,给系统测量带来了误差。为解决以上问题,本文开展了如下研究工作:1.提出了基于三角波条纹离焦投影的三维面形测量方法,并详细阐述了条纹离焦、Gamma效应等相关问题。该方法中对三角波条纹进行轻微距离空气离焦就能够滤除幅值较小的高次谐波,并滤除环境中存在的高频噪声,克服了Gamma效应;离焦距离更短,保证了较高的信噪比,使得相位获取更准确。MATLAB仿真模拟充分证明了该方法的有效性和可行性,通过实验对鼠标和长条物体进行面形测量,并将RMS控制在0.03mm以内。相较于传统方法,测量精度得到了较大提高。2.提出了基于三角波离焦条纹反射的三维面形测量方法,重点研究了反射镜面测量的原理、系统结构和系统标定等问题。该方法采用三角波条纹通过短距离空气传播微离焦,不仅避免了远距离离焦在镜面成像中引起的CCD相机无法拍摄到清晰的反射条纹像和相位获取准确率降低的问题;而且有效的降低了显示器的Gamma效应带来的测量误差。通过仿真模拟和实验,均验证了该方法的有效性和可行性。通过实验对曲率半径为1m,尺寸大小为80mm×80mm的标准凹面镜进行了测量,恢复面形RMS约为16.15um。
[Abstract]:Three-dimensional surface shape measurement technology based on optics has the advantages of non-contact, high precision and on-line detection. It has been applied in aerospace, automobile manufacturing, industrial production and so on. At present, the Gamma effect in the commonly used measurement system has seriously affected the measurement accuracy, and can not be used to effectively measure the mirror object. How to effectively overcome the Gamma effect. It is very important to improve the measurement precision and realize the 3D shape measurement of mirror object. In the traditional method, the binary fringe defocus measurement is used. It is generally used to adjust the active defocusing of projection equipment or to defocus automatically from the focal distance. The above two defocusing methods are relatively deep, which reduces the intensity of projection fringes and reduces the accuracy of phase acquisition. Thus, the measurement accuracy is affected. Because of the Gamma effect of the projector, there are quite a lot of high-order harmonics in the projection fringe, which reduces the quality of the fringe and brings error to the measurement system. In this paper, the following research work has been carried out: 1. A new method for measuring 3-D plane shape based on delocalization projection of triangular wave fringes is proposed, and the defocusing of fringes is described in detail. Gamma effect and other related problems. In this method, the high-order harmonics with small amplitude can be filtered and the high-frequency noise in the environment can be filtered by defocusing the triangulation wave fringe slightly in the air. The Gamma effect is overcome. The defocus distance is shorter, which ensures a higher SNR, which makes the phase acquisition more accurate. MATLAB simulation fully proves the effectiveness and feasibility of the method. The surface shape of mouse and strip is measured by experiments, and the RMS is controlled within 0.03mm. compared with the traditional method. The measurement accuracy has been greatly improved. 2. A new method of 3D surface shape measurement based on delocalization fringe reflection of triangular wave is proposed, and the principle of reflection mirror measurement is mainly studied. The system structure and system calibration are discussed in this paper. The triangular wave fringe is used to propagate micro-defocusing through short-range air. It not only avoids the problem that the CCD camera can not capture clear reflection fringe images and the accuracy of phase acquisition is decreased due to the defocusing in the long range. And the measurement error caused by the Gamma effect of the display is reduced effectively. The effectiveness and feasibility of the method are verified by simulation and experiment. The radius of curvature is 1 m through the experiment. The standard concave mirror with the size of 80mm 脳 80mm has been measured, and the RMS of the recovered surface is about 16.15um.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41

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