Effects of target structure on the performance of laser time-of-flight velocimeter systems.
Effects of target structure on the performance of laser time-of-flight velocimeter systems.
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目标结构对激光飞行时间测速系统性能的影响。
DOI：
10.1364/ao.36.000518
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发表时间：
1997
期刊：
影响因子：
1.9
通讯作者：
H. Yura
中科院分区：
文献类型：
--
作者：
B. Rose;H. Imam;S. Hanson;H. Yura
部分发达的散斑的后果和影响引起的偏差误差在速度测定的讨论相对于鲁棒性的经典激光飞行时间测速（LTV）系统。它表明，表面制度存在，定义部分开发的散斑的程度。这些制度进行了探索，理论和实验;表面模型的开发，以预测由此产生的交叉协方差，从速度估计可以得到。表面模型描述了由反射结构和不同的横向粗糙度尺度引起的互协方差的行为。特别是，它示出，它是可能的，以获得一个双高斯交叉协方差作为部分开发的斑点的存在的结果。所描述的所有模型进行了比较与实验观测的交叉协方差不同的表面制度。物体是在反射幅度、高度或两者中具有横向空间相关性的固体目标，通常引起部分发展的散斑。在几乎所有的情况下，与相应的理论预测良好的协议被发现。解相关引起的速度失调的交叉协方差的峰值显着移动，给出一个速度偏差。相应的理论模型的开发和实验验证。串扰测量已经进行，并与本文开发的理论进行比较。测量和理论都表明，只有与其对应的间隔相当或大于其对应的间隔的光斑尺寸才会导致互协方差最大值的时滞的可测量的峰值偏移。我们的结论是，LTV系统将在各种实际条件下提供准确的速度估计。
The consequences of partially developed speckle and the effects giving rise to bias errors in velocity determination are discussed with respect to robustness of a classical laser time-of-flight velocimetry (LTV) system. It is demonstrated that surface regimes exist that define the degree of partially developed speckle. These regimes are explored both theoretically and experimentally; surface models are developed to predict the resulting cross covariance from which velocity estimations can be obtained. The surface models describe the behavior of the cross covariance caused by reflection structures and with disparate lateral-roughness scales. In particular, it is shown that it is possible to obtain a twin-Gaussian cross covariance as a result of the presence of partially developed speckle. All models described are compared with experimental observations of the cross covariance for differing surface regimes. The objects are solid targets having lateral spatial correlations in reflection amplitude, height, or both, generally giving rise to partially developed speckle. In almost all cases good agreement with the corresponding theoretical predictions are found. Decorrelation caused by velocity misalignment is shown to shift the peak of the cross covariance significantly, giving a velocity bias. A corresponding theoretical model is developed and verified experimentally. Cross-talk measurements have been performed and compared with a theory developed herein. Both measurements and theory indicate that only spot sizes comparable with or larger than their corresponding separation will lead to a measurable peak shift of the time lag for the maximum of the cross covariance. We conclude that LTV systems will provide accurate velocity estimates under a wide variety of practical conditions.