Straightness Measurement Using Laser Diode and CCD Camera

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Study on Laser Visual Measurement Method for Seamless Steel PipeStraightness Error by Multiple Line-structured Laser Sensors

An original non-contact measurement method using multiple line-structured laser sensors is introduced for seamless steel pipe straightness error is in this paper. An arc appears on the surface of the measured seamless steel pipe against a line-structured laser source. After the image of the arc is accepted by a CCD camera, the coordinates of the center of the pipe cross-section circle containing the arc can be worked out through a certain algorithm. Similarly, multiple line-structured laser sensors are equipped parallel to the pipe. The straightness error of the seamless steel pipe, therefore, can be inferred from the coordinates of multiple cross-section centers obtained from every line-structured laser sernsor .     

Study on Laser Visual Measurement Method for Seamless Steel Pipe Straightness Error by Multiple Line- structured Laser Sensors

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基于激光准直直线度测量方法的研究

介绍了用半导体激光器、单模光纤准直激光束作为测量基准轴线,四象限光电器件作为位置传感器,并由单片机进行数据采集、处理与测量结果显示的直线度准直仪。通过稳定性实验、重复特性实验和双频干涉仪比对实验,验证了本直线度测量系统的可行性。实验结果表明,测量系统实现的测量精度为(1.0+2×L)μm(L为准直距离,单位为m),测量范围为10m。     

重心法在光电信号处理中的应用

为了测定光纤出射光斑坐标的位置,让光耦合进一根光纤,在光纤的另一端对出射的光斑用线阵ＣＣＤ进行扫描。针对接收到的一维方向上的光电信号数据,分别采用了最大值法、截止电压法和重心法进行处理,并对它们的结果进行了比较和分析。实验结果证明由重心法得到的信号位置具有重复精度高、稳定性好等特点。     

四芯光纤弯曲传感器

提出了一种新颖的基于四芯光纤的弯曲传感器,可用于弯曲测量。该传感器采用一段四芯光纤作为敏感单元,四芯光纤的四个纤芯作为一个四光束干涉仪,在光纤出射端远场形成周期分布的干涉格子。该四光束干涉仪的干涉相位差是光纤弯曲曲率半径的函数,因而,弯曲曲率半径的变化可导致格子光场的移动。波长为650 nm的低相干半导体激光二级管被用来做为光源,所形成的干涉格子光场由CCD探测器记录。理论上,建立了远场格子图案强度分布函数与曲率半径的关系,并得到了实验的验证。     

皮秒扫描相机在半导体激光管输出特性研究中的应用

本工作用Picotron 200型扫描相机和液态氮冷却的CCD摄相机系统对半导体激光二极管LTO22 MC的输出特性进行了测量,其最短输出脉冲宽度为2.1ps。这种半导体激光二极管的发射波长为780nm,连续工作条件下,其输出功率为3mW到5mW。     

一种位相板衍射图样的图像处理新方法

本文介绍了在半导体激光光纤和位相板相结合的准直情况下，利用ＣＣＤ探测器测量大尺寸形位误差的原理，并针对位相板衍射图像的特点，提出了一种处理此类衍射图样的图像处理新方法——投影法。同在时间上采用的多次平均的方法相比较，投影法相当于采用了空间上的平均，消除了ＣＣＤ表面保护玻璃形成的干涉条纹的影响，对空气扰动也起到了很好的抑制作用。并且使二维图像处理变为一维计算，大大提高了计算速度     

High-accuracy long distance alignment using single-mode optical fiber and phase plate

A long distance alignment technique is developed using the combination of a single-mode optical fiber and a phase plate. The characteristics of the diffraction pattern of a Gaussian beam passing through a π step phase plate are analyzed theoretically. The feasibility of the method is validated in theory and with computer-simulation, and the factors affecting the alignment precision are discussed. The reliability of the alignment technique is demonstrated when it is used in the measurement of the straightness of a 12 m-track, in which measured results using the new technique coincide very well with those using an HP5528 dual frequency laser interferometer.     

Non-contact scanning measurement utilizing a space mapping method

In this study, a novel approach to a measuring methodology and calibration method for an optical non-contact scanning probe system is proposed and verified by experiments. The optical probe consists of a line laser diode and two charge-coupled device (CCD) cameras and is placed on a computer numerical control (CNC) machine to measure the workpiece profiles. A space mapping method using the least-squares algorithm is presented for the probe calibration and profile measurement. This method provides a simple and accurate calculation of the relationship between the real space plane and its related image space plane in a CCD camera. A transparent grid with regularly spaced nodal points is used to construct the space mapping function. The space coordinate of an object can be obtained from its image in the CCD camera via the mapping function. The measured profile data are smoothed by the B-spline blending function and can be transferred to a CAD/CAM package for industrial applications. Experimental results show that this technique can determine the 3-D profile of an object with an accuracy of 60 μm.