In this paper, we propose a novel city-scale distance sensing algorithm based on atmosphere optics. The suspended particles, especially in bad weather, would attenuate the light at almost all wavelengths. Observing this fact and starting from the light scattering mechanism, we derive a bispectral distance sensing algorithm by leveraging the difference of extinction coefficient between two specifically selected near infrared wavelengths. The extinction coefficient of the atmosphere is related to both wavelength and meteorological conditions, also known as visibility, such as the fog and haze day. To account for different bad weather conditions, we explicitly introduce visibility into our algorithm by incorporating it into the calculation of extinction coefficient, making our algorithm simple yet effective. To capture the data, we build a bispectral imaging system that is able to take a pair of images with a monochrome camera and two narrow band-pass filters. We also present a wavelength selection strategy that allows us to accurately sense distance regardless of material reflectance and texture. Specifically, this strategy determines two distinct near infrared wavelengths by maximising the extinction coefficient difference while minimizing the influence of building’s reflectance variance. The experiments empirically validate our model and its practical performance on the distance sensing for the city-scale buildings.

中文翻译：

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恶劣天气下通过双光谱消光实现的城市规模距离感测

本文提出了一种基于大气光学的新型城市尺度距离传感算法。悬浮颗粒，特别是在恶劣天气下，会衰减几乎所有波长的光。观察到这一事实并从光散射机制开始，我们利用两个专门选择的近红外波长之间的消光系数差异，推导了双光谱距离传感算法。大气的消光系数与波长和气象条件（也称为能见度）有关，例如雾天和阴霾天。为了解决不同的恶劣天气条件，我们通过将其纳入消光系数计算中，将可见性明确引入算法中，从而使算法简单而有效。要捕获数据，我们构建了一个双光谱成像系统，该系统能够使用单色相机和两个窄带通滤波器拍摄一对图像。我们还提出了一种波长选择策略，该策略使我们能够准确地感应距离，而不管材料的反射率和纹理如何。具体而言，此策略通过最大化消光系数差异同时最小化建筑物的反射率差异的影响来确定两个不同的近红外波长。实验从经验上验证了我们的模型及其在城市规模建筑物的距离感测中的实际性能。具体而言，此策略通过最大化消光系数差异同时最小化建筑物的反射率差异的影响来确定两个不同的近红外波长。实验从经验上验证了我们的模型及其在城市规模建筑物的距离感测中的实际性能。具体而言，此策略通过最大化消光系数差异同时最小化建筑物的反射率差异的影响来确定两个不同的近红外波长。实验从经验上验证了我们的模型及其在城市规模建筑物的距离感测中的实际性能。