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1.
In this paper a new approach to enhance the dynamic range of a fringe projection system for measuring 3D profile of objects with wide variation in their optical reflections is proposed. The high dynamic range fringe images are acquired by recursively controlling the intensity of the projection pattern at pixel level based on the feedback from the reflected images captured by the camera. A four step phase shifting algorithm combined with a quality guided algorithm is used to obtain the unwrapped phase map of the object from the acquired high dynamic range fringe images. Simulation and experimental results show that the proposed technique can accurately measure the 3D profile of objects with wide variation in their optical reflectivity.  相似文献   

2.
黄荻  鄢立 《光学仪器》2009,31(5):6-9
光学中心偏测量对光学系统的检验和装校起着重要的作用,光轴拟合则是对中心偏测量数据的优化过程。提出了一种光轴拟合的新方法。该方法具有一些特点:原理上更科学,符合光学测量的实际;数学模型简单,易于编程实现;可以响应一些特殊的测量要求。该方法已经用于对多组实测数据进行优化,达到了预期的优化效果。  相似文献   

3.
We present a new reconstruction method for measuring profile of large, ultraprecise absolute optical surfaces with a compact interferometer. The profile of workpiece can be reconstructed exactly with high lateral resolution and large non-equidistant scanning step. Both systematic errors of the interferometer and height offsets of the scanning stage can be eliminated. Additional angular measurement can be used to measure pitching angles of the scanning stage. The exact reconstruction method is verified by computer simulation and on-machine measurement experiment.  相似文献   

4.
Four methods aiming at measuring rotary machine axis center trace are discussed in detail. The comparative analysis is made on some aspects such as measurement accuracy, on-machine characteristics, feasibility, practical operation convenience and the integrity of measurement information. In order to simplify measurement, the axis profile error is ignored in traditional condition, while the measurement accuracy will be reduced. The 3-point method that the axis profile error is firstly separated has better real time character, at the same time, not only the axis motion error but also the axis profile error can be measured. All of those information can be used to diagnose the fault origin. The analysis result is proved to be correct by the experiment.  相似文献   

5.
介绍了一种应用于齿轮测量中心上复杂齿廓测量的新方法——啮合线齿廓测量法。该方法减小了测头在X轴方向上运动距离,有效地保证了精度范围,同时减小测头重力中心的运动及测量时间,实现了高精度测量。该方法能够有效防止齿廓基圆测量法在进行内齿轮测量时的干涉现象,同时实现小直径内齿轮(外圆直径小于10mm)的一次装卡完成齿形、齿向和齿距误差测量。  相似文献   

6.
在机械行业中,轴承、光学器件、计算机芯片等的运行状况均取决于其表面形貌的实际情况,采用二维形貌测量仪可以精密地对其进行测量.介绍了二维形貌测量仪的测量原理和结构设计,并提出了一整套设计思路和数据处理方法.  相似文献   

7.
针对航空叶片型面复杂、曲率变化大的特点,提出一种应用锥光偏振全息原理的测量方法,该方法采用同一束锥光照明,允许被测表面的法向方向与光轴的夹角有较大的变动范围,从而避免叶片曲率变化对测量的影响。在此基础上,利用提出的基于隐式多项式的数据配准算法实现测量数据与CAD模型数据的同位姿化,获得叶片型面误差分布及相关几何参数的偏差,为加工工艺参数的调整提供精确的参数。实验结果表明,该方法测量重复性小于8μm,达到航空叶片自适应加工对测量的要求。  相似文献   

8.
A method for measuring the accuracy of rotating objects was studied. Rotating axis errors are significant; such as the spindle error of a machine tool which results in increased surface roughness of machined work pieces. Three capacitance-type displacement sensors were used to measure the position of a rotating master ball. The sensors were mounted at the three orthogonal points on the spindle axis. The measurement data were analysed for rotating spindle accuracy, not only for the average roundness error but also for the spindle volumetric positional error during rotation. This method is simple and economical for industrial field use for regular inspection of spindles using portable equipment. The time taken for measurement and analysis using this method is only about two hours. This method can also measure microscopic amplitudes in 3-D directions of vibrating objects.  相似文献   

9.
Tracking of moving objects within video streams is a complex and time-consuming process. Large number of moving objects increases the time for computation of tracking the moving objects. Because of large computations, there are real-time processing problems in tracking of moving objects. Also, the change of environment causes errors in estimation of tracking information. In this paper, we present a new method for tracking of moving objects using optical flow motion analysis. Optical flow represents an important family of visual information processing techniques in computer vision. Segmenting an optical flow field into coherent motion groups and estimating each underlying motion are very challenging tasks when the optical flow field is projected from a scene of several moving objects independently. The problem is further complicated if the optical flow data are noisy and partially incorrect. Optical flow estimation based on regulation method is an iterative method, which is very sensitive to the noisy data. So we used the Combinatorial Hough Transform (CHT) and Voting Accumulation for finding the optimal constraint lines. To decrease the operation time, we used logical operations. Optical flow vectors of moving objects are extracted, and the moving information of objects is computed from the extracted optical flow vectors. The simulation results on the noisy test images show that the proposed method finds better flow vectors and more correctly estimates the moving information of objects in the real time video streams.  相似文献   

10.
梁铨廷 Yu  W 《仪器仪表学报》1996,17(4):366-371
本文阐述应力型保偏光纤应力测量的原理和方法,即所谓光测弹性CT技术。简单介绍基于光测弹性CT技术研制成的应力自动测量装置,以及用这种装置对一种Bow—Tie保偏光纤的测量结果。  相似文献   

11.
本文对准直激光束检测非球面方法进行了研究。它不用接触被检件表面,同时也无须处理干涉条纹。测量时只要保证激光细束保持一致的入射方向扫描被检表面,用CCD光电探测器检出面形的斜率变化,而后在扫描范围内积分便能获得面形高度。本文以测量光学系统中用于波面补偿目的的旋转对称镜面为例对测量系统进行分析。该系统不仅可以进行一维测量,通过转台旋转亦可进行二维测量,通过面形重构获得三维的被测体面形。给出了三维面形重构方法,并编制数据处理软件,可以把测量数据处理成高度曲线或三维面形。  相似文献   

12.
邓文怡  吕乃光 《工具技术》1998,32(12):34-36
提出一种利用人工神经网络对零件三维表面轮廓进行非接触测量的新方法,介绍了光学系统、数据获取、训练反向传播神经网络确定系统映射函数以及零件三维曲面测量方法和实例。该方法可降低对测量系统精度的要求,并且不需要精确调整成像系统和预先精确测定系统参数。  相似文献   

13.
本文对准直激光束检测非球面方法进行了研究。它不用接触被检件表面,同时也无须处理干涉条纹。测量时只要保证激光细束保持一致的入射方向扫描被检表面,用CCD光电探测器检出面形的斜率变化,而后在扫描范围内积分便能获得面形高度。本文以测量光学系统中用于波面补偿目的的旋转对称镜面为例对测量系统进行分析。该系统不仅可以进行一维测量,通过转台旋转亦可进行二维测量,通过面形重构获得三维的被测体面形。给出了三维面形重构方法,并编制数据处理软件,可以把测量数据处理成高度曲线或三维面形。  相似文献   

14.
采用间接测量法对平面3-RPR机构进行运动学标定的仿真   总被引:1,自引:0,他引:1  
采用间接测量对平面机构进行标定时,需要引进标准测量参照物,但参照物本身仍可能存在一定的尺寸误差;另外间接测量时要不断变换标准测量参照物的位置,又会引进位置误差。为便于解决实际问题,使研究更具可操作性,将上述误差和待标定的机构结构误差一起考虑对机构进行了标定仿真,同时在仿真过程中采用矩阵重构的方法来解决测量误差扰动的问题,避免了大规模的空间寻优。仿真结果表明,可以通过让动平台走过不同的轨迹组合来实现对平面机构的标定。  相似文献   

15.
16.
A non-interferometric imaging technique in conjunction with Abel inversion is used to directly and quantitatively examine the changes in optical fibers due to the heating produced during arc-fusion splicing as a function of fusion arc parameters. Phase images in the vicinity of a fusion splice are obtained using Quantitative Phase Microscopy, allowing the refractive-index change to be reconstructed with high spatial resolution. This simple, nondestructive method confirms that, for a fixed arc current, while the fusion time increases, the refractive-index of both fiber cores within the fusion region decreases in magnitude, the core region broadens, and the axial gradient decreases.  相似文献   

17.
In the last few years, the automation of optical measurement has gained more and more importance. Electro-optical sensor systems are offered which permit the automation of long-established and common measuring devices such as measuring microscopes and profile projectors. Moreover, a new generation of non-contact co-ordinate measuring devices is emerging. Apart from these measuring devices for universal application, optical sensor systems with their peripheral components are also used for specific measuring tasks. This paper describes special system configurations with their advantages and disadvantages. The possibilities which exist in this field will be discussed on the basis of three examples taken from industrial measurement practice.  相似文献   

18.
传统的光学测量定中心法受限于光源、转台大小和装调误差传递性而不适用于大口径、多透镜光学系统的装调,为此本文提出了使用三坐标测量仪接触式测定透镜中心的精密机械测量法。介绍了使用三坐标测量仪测量大口径透镜中心偏的原理,即在测量透镜上表面与基准轴等距离各点坐标的基础上拟合得到透镜光轴与基准轴的夹角,从而解算出透镜的中心偏。通过大口径长焦距镜头的装调对该方法进行了检验。检验结果表明:该透镜的装调偏差为6.47″,重复性误差为(1.16×10-4)″。该方法将光学测量变为机械测量,利于装调,可在保证装调精度的同时简化装调难度,提升装调效率,满足大口径多透镜光学系统对高精度装调的要求。  相似文献   

19.
In this paper, an innovative optical-based method and automation system for measuring the cross-sectional web thickness of microdrills is introduced. The presented measuring method is a rapid and non-destructive means based on the use of an optical micrometer (OM) as essential equipment to determine the cross-sectional outer diameter and the dual cross-sectional flute depths of the microdrill. To this end, the OM must be set to a particular orientation so that the included angle between the optical measuring plane of the OM and the central axis of the microdrill is consistent with the helix angle of the helical flutes of the microdrill, and the microdrill must be rotated around its central axis for implementing the measurement. The cross-sectional web thickness of the microdrill can thus be calculated through the difference between the determined cross-sectional outer diameter and dual cross-sectional flute depths. An optical-based measuring automation system was constructed for implementing the proposed method through an established automated measuring process. Experiments to measure the web thickness of microdrill samples were conducted. It showed that the presented method and automation system could achieve good repeatability and accuracy with sufficient efficiency. The proposed measuring method, combined with the constructed measuring automation system, had been validated feasible and effective for the web thickness measurement of certain microdrills.  相似文献   

20.
Transparent objects (phase objects) are not visible in a standard brightfield optical microscope. In order to see such objects the most used technique is phase-contrast microscopy. In phase-contrast microscopy the contrast observed is proportional to the optical path difference introduced by the object. If the index of refraction is uniform, phase-contrast microscopy then yields a measure of the thickness profile of phase objects. We show that by slightly defocusing an optical microscope operating in brightfield, phase objects become visible. We modeled such an effect and show that the image contrast of a phase object is proportional to the amount of defocusing and proportional to the two-dimensional Laplacian of the optical path difference introduced by the object. For uniform index of refraction, defocusing microscopy then yields a measure of the curvature profile of phase objects. We extended our previous model for thin objects to thick objects. To check our theoretical model, we use as phase objects polystyrene spherical caps and compare their curvature radii obtained by defocusing microscopy (DM) to those obtained with atomic force microscopy (AFM). We also show that for thick curved phase objects one can reconstruct their thickness profiles from DM images. We illustrate the utility of defocusing microscopy in biological systems to study cell motility. In particular, we visualize and quantitatively measure real-time cytoskeleton curvature fluctuations of macrophages (a cell of the innate immune system). The study of such fluctuations might be important for a better understanding of the engulfment process of pathogens during phagocytosis.  相似文献   

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