无源温度计：理论和概念验证
Passive scintillometer: Theory and proof of concept
摘要：
我们提出了一种低成本的被动式湍流计的设计，通过分析两个区域之间的均匀，但不同的亮度的直边的图像中的闪烁来测量光学湍流的强度。基于相位屏和严格的路径积分传播成像模型，提出了两种理论方法来描述湍流。两种模型的渐近分析导致四个不同的成像情况。我们提出了两个统一的近似，涵盖了最有前途的结论，为被动微波计的应用。闪烁强度和闪烁区的宽度都可以用来估计湍流强度。我们提出了概念验证实验的结果，其中专门制作的目标的图像由配备有长焦镜头的消费级相机拍摄。我们描述的图像处理，分离的目标特性的湍流。计算了三个光谱波段和几个孔径下图像方差的空间分布。正如预期的那样，闪烁主要集中在尖锐的边缘，而在目标的均匀明亮部分则不存在。观察到的边缘闪烁的方差在理论范围内，并提供合理的估计的湍流结构常数在三个光谱带。然而，闪烁区的宽度和对孔径的依赖性与用于较大孔径的薄透镜成像理论不一致。我们将此归因于对条形目标的附加台架测试显示，相机和透镜分辨率远低于标称薄透镜衍射极限，并且应使用不同的光学设置以利用波动的空间分布和孔径依赖性。
英文摘要：
We propose design of a low-cost passive scintillometer that measures the strength of optical turbulence by analyzing scintillation in the image of a straight edge between the two areas of uniform, but distinct brightness. Two theoretical approaches to scintillations description are developed that are based on the phase screen and rigorous path integral propagation imaging models. Asymptotic analysis of both models leads to four distinctive imaging situations. We propose two uniform approximations that cover the most promising conclusion for the passive scintillometer applications. Both the strength of scintillation and the width of the area where scintillations exist can be used to estimate the turbulence strength. We present the results of the proof-of-concept experiment where images of the specifically made target were taken by a consumer grade camera equipped with a telephoto lens. We describe the image processing that separates the target characteristics from the turbulence scintillations. The spatial profiles of the image variances at three spectral bands and for several apertures were calculated. As was expected, scintillations are concentrated around the sharp edge and are absent at the uniformly bright parts of the target. Observed edge scintillation variances are within the theoretical limits, and provide reasonable estimates for the turbulence structure constant across the three spectral bands. However, the width of the scintillation area and dependence on the aperture are inconsistent with the thin lens imaging theory for larger apertures. We attribute this to the Additional bench tests on bar targets revealed that the camera and lens resolution are well below the nominal thin lens diffraction limit, and a different optical setup should be used in order to exploit the spatial distribution and aperture dependence of fluctuations.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
