Laser-speckle angular-displacement sensor: theoretical and experimental study.
Laser-speckle angular-displacement sensor: theoretical and experimental study.
复制标题
激光散斑角位移传感器：理论和实验研究。
DOI：
10.1364/ao.37.002119
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发表时间：
1998
期刊：
影响因子：
1.9
通讯作者：
R. Hansen
中科院分区：
文献类型：
--
作者：
B. Rose;H. Imam;S. Hanson;H. Yura;R. Hansen
据我们所知，提出了一种测量任意形状物体角位移的新颖方法，其中角位移垂直于光轴。该方法基于对照射目标的单个激光束的散射场进行傅里叶变换。目标处光场的角度分布被线性映射到放置在傅立叶平面中的线性图像传感器上。测量该位移有助于确定目标的角位移。理论和实验都证明，如果将线性图像传感器放置在傅里叶平面上，角位移传感器对物体形状和目标距离不敏感。提出了在傅立叶平面中定位图像传感器的简单程序。目标的任何横向或纵向移动都会引起部分散斑去相关，但不会影响角度测量。此外，照明波长的任何变化都不会影响角度测量。理论和实验表明，该方法对于小角位移具有0.3 mdeg（约5 murad）的分辨率，并讨论了进一步提高分辨率的方法。对于产生充分发展的散斑的表面，不需要特殊的表面处理。从理论上和实验上都考虑了部分发展的散斑的影响。
A novel, to our knowledge, method for the measurement of angular displacement for arbitrarily shaped objects is presented in which the angular displacement is perpendicular to the optical axis. The method is based on Fourier-transforming the scattered field from a single laser beam that illuminates the target. The angular distribution of the light field at the target is linearly mapped on a linear image sensor placed in the Fourier plane. Measuring this displacement facilitates the determination of the angular displacement of the target. It is demonstrated both theoretically and experimentally that the angular-displacement sensor is insensitive to object shape and target distance if the linear image sensor is placed in the Fourier plane. A straightforward procedure for positioning the image sensor in the Fourier plane is presented. Any transverse or longitudinal movement of the target will give rise to partial speckle decorrelation, but it will not affect the angular measurement. Furthermore, any change in the illuminating wavelength will not affect the angular measurements. Theoretically and experimentally it is shown that the method has a resolution of 0.3 mdeg ( approximately 5 murad) for small angular displacements, and methods for further improvement in resolution is discussed. No special surface treatment is required for surfaces giving rise to fully developed speckle. The effect of partially developed speckle is considered both theoretically and experimentally.