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1.
针对目前相移控制器件费用高、操作复杂等不足,提出了一种数字相移方法.并将其与全息干涉术相结合,进行了相移全息干涉术的实验研究.应用MATLAB软件,结合图像处理方法,通过对全息干涉条纹精确控制使其定向移动,实现了四步相移,获得4个干涉图.应用四步相移法原理和相位去包裹方法,最终成功求得物体变形引起的三维位相差,实现物体变形的三维测试.实验表明,该方法不仅简化了全息干涉测试的光学装置,避免传统相移器件相移精度低、容易造成相移误差的缺点,且操作简单,测试精度高,其精度容易达到1/10波长.  相似文献   

2.
胡浩  梁晋  唐正宗  卢岗 《光学精密工程》2012,20(7):1636-1644
提出了一种基于数字图像相关法和双目视觉技术的全场三维变形测量方法来测量金属薄板焊接过程中的高温变形.首先,提出一种基于种子点的高精度图像匹配算法求解相关匹配非线性优化初值.然后,介绍了三维坐标重建以及三维位移、三维应变的求解算法.最后,借助于VC+ +6.0开发环境,研制了用于薄板焊接全场变形测量的实验系统.为验证本文方法在材料力学性能实验方面的可行性,利用标准材料试验机和自主研制的图像采集装置设计了钢试件的标准拉伸实验,并采用Q235板材件进行了焊接变形测量实验.实验表明:本文方法的应变测量精度为0.5%,与引伸计的测量结果基本相当;与传统的测量方法相比,提出的方法可以更全面、更直观地测量金属薄板在整个焊接过程中的三维移和应变场,并且测得的3个方向的位移变化曲线过渡自然、数据合理,是研究焊接变形规律的有效手段.  相似文献   

3.
基于光纤的三维电子散斑干涉测量系统设计   总被引:4,自引:2,他引:2  
周文静  于瀛洁 《光学精密工程》2008,16(10):1815-1821
为了实现物体三维变形非接触测量,设计了基于电子散斑干涉技术的三维变形测量系统。该系统中采用了一分五型分束光纤,这根光纤在系统中起到分光和传光的作用,使系统所需器件相比一般的设计系统要少。为了获得变形的量化数值,系统将电子散斑技术与相移技术结合在一起,由压电陶瓷引入相移,并采用“4+1”相移算法计算变形量。该系统可以实现面内及离面变形的独立测量,进而实现物体三维变形的测量。以带缺陷的木板和钢板为测试对象,进行了物体面内、离面和三维变形的测量,结果表明设计系统可以实现各种变形的测量。  相似文献   

4.
用数字散斑法测量铜/铝复层板拉伸变形   总被引:1,自引:1,他引:0  
孙涛  梁晋  蔡勇  王伊卿 《光学精密工程》2012,20(12):2599-2606
提出了一种基于数字散斑相关法和双目立体视觉技术的全场三维变形测量方法,实现了对爆炸焊接制备的铜/铝复层材料的变形测量。研究了该方法所涉及的数字散斑相关算法、三维坐标、位移和应变计算等关键技术,借助于VC++6.0开发环境,研制并开发了用于铜/铝复层板全场变形测量的试验系统及其软件。为了验证本文所述测量方法的可行性,进行了精度验证实验和铜/铝复层板单向拉伸试验,且对复层板拉伸试验结果与有限元软件Abaqus数值模拟结果进行了对比分析。结果表明:本文方法的应变测量精度优于0.5%,与引伸计测得的结果基本相当;测得的应变极值分布与有限元模拟结果很吻合;在板料发生颈缩前,塑性应力-应变模拟曲线与试验结果很吻合;整个变形过程中位移-载荷模拟曲线的变化趋势与试验结果一致,模拟得到的极限载荷的相对误差为0.06%~2.25%。实验结果说明,数字散斑方法是一种精确获得复层板料全场应变的有效手段。  相似文献   

5.
基于ESPI技术的物体缺陷自动识别技术   总被引:1,自引:0,他引:1  
电子散斑干涉技术是变形和缺陷检测的重要技术方法,具有非接触、动态特性好、灵敏度高等优点.在缺陷检测中,以变形为载体,通过变形分布上的异常判别缺陷是否存在和大致位置.在这个过程中,如何摆脱人的主观判断,实现缺陷的自动识别,一直是一个技术难点.本文以实现缺陷自动识别为目标,探讨了电子散斑干涉技术的物体缺陷识别技术.总结了ESPI实现系统和变形测量的主要算法,包括时域相移干涉仪中算法、空域载波相移干涉仪中算法及空域相移干涉仪中算法,分析了各自的特点并进行了归类.描述了变形与缺陷之间的关系.讨论和总结了缺陷的时域识别方法和空域识别方法.分析了基于变形梯度的缺陷识别方法,并进行了改进.改进的方法引入了调节因子,提高了缺陷区与非缺陷区之间的界限,从而提高了该方法的缺陷识别能力.  相似文献   

6.
提出了一种基于相移和颜色分光的电子散斑干涉(ESPI)瞬态三维变形测量方法,该方法包括一个彩色CCD和红绿蓝三种不同波长的激光器,可同时采集来自三路的散斑干涉图像。物体面内水平方向、竖直方向以及离面方向的散斑干涉图像信息通过颜色分光实现分离,并利用相移算法对散斑干涉条纹图进行分析处理,分别解调出水平、竖直及离面方向的变形场相位,实现三维变形场的测量。模拟及实验分析表明,此方法能同时实现物体面内水平方向、竖直方向以及离面方向的变形测量,可用于物体表面的三维瞬态变形测量,也可单独完成面内或离面的二维变形测量。  相似文献   

7.
输电塔架承载变形的三维光学测量   总被引:1,自引:1,他引:0  
考虑输电塔架结构复杂,需要做承载变形真型实验来检测塔架实际承载能力的问题,本文提出了一种三维全场变形光学测量方法来解决塔架真型试验中存在的大尺寸、大变形、多测点、三维变形、塔架承载形态保持时间短等测量难点.该方法基于工业近景摄影测量技术重建单个状态下塔架测点的三维结构,利用具有身份信息的人工标志点来实现不同状态测量结果的对齐.通过跟踪固定在塔架上的变形点,计算相应部位的位移来获取真型塔架在不同负载下的整体变形.精度评估实验表明,提出的方法测量精度优于0.1 mm/4 m;真型实验显示,测量结果能够为塔架结构力学性能分析和改进塔架设计提供有价值的参考数据.该方法具有现场工作量小、不干扰测量对象、量程弹性大等优点,能够满足各型塔架三维变形测量对效率和精度的要求.  相似文献   

8.
飞机结构件运动数据的动态视觉测量系统   总被引:2,自引:1,他引:1  
基于近景摄影测量理论和立体视觉技术,提出并实现了一种针对机身结构件在飞行状态下的轨迹、姿态、位移、变形等多种运动数据的动态视觉测量方法.研究了基于工业近景摄影测量的多相机快速自标定方法;飞行状态下相机动态定位及抖动消除技术;刚性结构件的运动轨迹及姿态的快速求取和通过多相机(≥3)协作实现非编码标志点阵列的精确匹配等多项关键技术.在模拟飞行环境下的实验结果表明,相机标定的重投影误差小于0.03 pixel,系统的运动轨迹姿态测量精度可达0.01 mm/1 m,关键点位移变形测量精度可达0.05 mm/1 m,基本满足飞机测试行业的精度和可靠性测量标准.  相似文献   

9.
提出一种基于彩色三步相移算法和DLP Light Crafter 4500的实时相位测量轮廓术。在测量系统中,DLP Light Crafter 4500快速有序地投影MATLAB生成的三帧相移量为2π/3的R、G、B调制正弦相移光栅条纹到被测物体表面,一台与DLP Light Crafter 4500投影光栅条纹信号同步的高速黑白CMOS相机拍摄受被测物体面形调制的变形条纹。由于捕获的变形条纹间存在颜色失衡,需要采用校正算法进行校正。基于传统的三步相移技术,利用校正后的三帧变形条纹图像可以实时重建被测物体的三维形貌。  相似文献   

10.
颜国霖  林琳 《机电技术》2010,33(5):14-17
投影光栅相位法(PMP)是一种基于光栅投影和相位测量的光学三维轮廓测量技术,可实现物体表面三维轮廓的自动测量。提出了结合投影仪移轴技术的平行光轴系统,利用计算机编程生成具有高对比度和高亮度、有相差的正弦光栅,用数字投影仪LCD将这些条纹依次投射到被测物体表面,由CCD摄像机获取受物体表面面形调制的变形光栅像,根据数字相移算法计算出相位分布再通过相位展开恢复出连续相位分布,由相位.高度关系最终求出物体轮廓的三维数据信息。针对该原理进行了阐述,并给出了详尽的算法及实验结果。通过MATLAB实验仿真,对条纹图像进行处理和轮廓重构。模拟实验证明,这种测量方法快速高效、分辨率高,且易于实现。  相似文献   

11.
A method is described for the reconstruction of the amplitude and phase of the object exit wave function by phase-plate transmission electron microscopy. The proposed method can be considered as in-line holography and requires three images, taken with different phase shifts between undiffracted and diffracted electrons induced by a suitable phase-shifting device. The proposed method is applicable for arbitrary object exit wave functions and non-linear image formation. Verification of the method is performed for examples of a simulated crystalline object wave function and a wave function acquired with off-axis holography. The impact of noise on the reconstruction of the wave function is investigated.  相似文献   

12.
为实现基于数字全息的三维轮廓测量,本文探讨了菲涅耳近似算法实现数字全息相位再现的误差及抑制技术。首先理论分析了基于菲涅耳近似算法实现全息相位再现所包含的误差项,然后计算机模拟了数字离轴全息图的记录和相位再现结果,在此基础,模拟分析了离焦误差、数字再现光波误差及样本深度对相位再现的影响。针对记录参考光波和光学器件所引入的相位误差及其不定性,本文提出利用相位相减全息图处理方法加以消除,并给出了实验结果加以验证。模拟分析结果表明,菲涅耳近似算法误差、离焦误差、数字再现光波倾斜误差、解包裹错误对相位再现结果都有不同程度的影响。若获得高精度的再现结果,对记录过程、再现参数选择和处理方法都要进行严格控制或适当的选取。  相似文献   

13.
An in-plane and out-of-plane deformation simultaneous measurement method using only two speckle patterns grabbed before and after deformation of an object with rough surfaces using two cameras has been proposed. However, there are some problems concerning the setup of optical system, the aspect ratio of grabbed image data and so on in the conventional method. To solve these problems, the new optical system is proposed by using the multi-recording technology. Though multi-recording technologies have been already employed conveniently in the off-axis digital holography, the technologies have not been used functionally enough in speckle interferometry. In this paper, an in-plane and out-of-plane deformation simultaneous measurement is performed by the proposed method based on multi-recording technology in speckle interferometry. From experimental results, it can be confirmed that the proposed optical system can measure simultaneously in-plane and out-of-plane deformations in high resolution by one camera.  相似文献   

14.
Optical thickness variation is a fundamental characteristic of transparent optical devices. When measuring this variation by using a wavelength-tuning Fizeau interferometer, the measurement accuracy depends on the phase-shifting algorithm being used. Therefore, the phase-shifting algorithm should compensate for any errors incurred during the measurement, including the phase-shift error, coupling errors, and bias modulation of intensity. Among these errors, however, the coupling errors between the higher harmonics resulting from the inner reflections of the transparent plate and phase-shift error have not previously been considered. This paper presents a derivation of a 19-sample phase-shifting algorithm that can compensate for the miscalibration and 1st-order nonlinearity of the phase shift, coupling errors, and bias modulation of intensity during wavelength tuning. The characteristics of the 19-sample algorithm were estimated with respect to the Fourier representation in the frequency domain. The phase error of measurements performed using the 19-sample algorithm was discussed and compared with that of measurements obtained using other conventional phase-shifting algorithms. Finally, the optical thickness variation of a fused silica parallel plate was obtained using a wavelength-tuning Fizeau interferometer and the 19-sample algorithm. The measurement accuracy was discussed by comparing the ripples in the crosstalk noise with those calculated using other phase-shifting algorithms. The experimental results indicated that the optical thickness variation measurement accuracy for the fused silica plate was approximately 2 nm.  相似文献   

15.
最小交叉熵图像重建算法   总被引:2,自引:1,他引:1  
CT技术通过扫描和图像重建算法,获取被检物场断层图像.由于具有非侵入性、可视化等特点,该技术在工业领域获得广泛应用.为了提高CT系统重建图像的分辨率,提出一种信息扩充策略,并以此为基础采用两种最小交叉熵算法--MAP和SMART,对多相流CT系统进行图像重建.与传统ART算法相比,最小交叉熵算法有效提高了重建图像的分辨率,减少重构图像伪影.仿真和实验结果表明,基于信息扩充的SMART算法不仅改进了重建图像质量,而且提高了实时性.  相似文献   

16.
Optical interferometry is a powerful tool for measuring and characterizing areal surface topography in precision manufacturing. A variety of instruments based on optical interferometry have been developed to meet the measurement needs in various applications, but the existing techniques are simply not enough to meet the ever-increasing requirements in terms of accuracy, speed, robustness, and dynamic range, especially in on-line or on-machine conditions. This paper provides an in-depth perspective of surface topography reconstruction for optical interferometric measurements. Principles, configurations, and applications of typical optical interferometers with different capabilities and limitations are presented. Theoretical background and recent advances of fringe analysis algorithms, including coherence peak sensing and phase-shifting algorithm, are summarized. The new developments in measurement accuracy and repeatability, noise resistance, self-calibration ability, and computational efficiency are discussed. This paper also presents the new challenges that optical interferometry techniques are facing in surface topography measurement. To address these challenges, advanced techniques in image stitching, on-machine measurement, intelligent sampling, parallel computing, and deep learning are explored to improve the functional performance of optical interferometry in future manufacturing metrology.  相似文献   

17.
In the semi-free acoustic field, the actual acoustic pressure at any point is composed of two parts: The direct acoustic pressure and the reflected acoustic pressure. The general acoustic holographic theories and algorithms request that there is only the direct acoustic pressure contained in the pressure at any point on the hologram surface, consequently, they cannot be used to reconstruct acoustic source and predict acoustic field directly. To take the reflected pressure into consideration, near-field acoustic holography for semi-free acoustic field based on wave superposition approach is proposed to realize the holographic reconstruction and prediction of the semi-free acoustic field, and the wave superposition approach is adopted as a holographic transform algorithm. The proposed theory and algorithm are realized and verified with a numerical example, and the drawbacks of the general theories and algorithms in the holographic reconstruction and prediction of the semi-free acoustic field are also demonstrated by this numerical example.  相似文献   

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