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Rapport (Rapport De Recherche) Année : 2017

Measurement of Visibility Conditions with Traffic Cameras

Résumé

A computer vision method was proposed in 2011 by Ifsttar to estimate the meteorological optical range with a roadside camera in daytime conditions. The method was developed thanks to a set of images collected with a basic CCTV camera installed on a weather observation site alongside with reference visibility and luminance meters, between February 27 and March 1st 2009. In order to validate the method, we are collecting images and weather data from different sites. Meanwhile, we have implemented the method in C, and tested it with images and data collected on the original observation site in March and April 2009. The first Section of this report recalls the visibility estimation method. The second Section describes the implementation of the method. The third Section focuses on the detection of Lambertian surfaces in the scene. The fourth Section shows some results for different low visibility episodes. These results are then discussed and the next steps toward deployment are listed. We found that the Lambertian map is not always successful at suppressing the influence of illumination in the scene. We also found that the calibration of the method is affected by the fact that visibility extracted from an image is instantaneous whereas visibility measured by a scatter meter is averaged over 1 minute or more. Finally, we confirmed that the range of the method is limited by the characteristics of the camera. For further tests, we will use the data which we are currently collecting from other sites. When possible, we will need to collect sequences of images instead of single frames every 10', to smooth out insignificant variations. We will also need to estimate the depth map of the scene, to explore the possibility of calibrating the method without reference meteorological optical range data. We intend to investigate alternative local contrast estimation methods and an alternative calibration method for the response curve.
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Dates et versions

hal-02504366 , version 1 (10-03-2020)

Identifiants

  • HAL Id : hal-02504366 , version 1

Citer

Eric Dumont, Jean-Philippe Tarel, Nicolas Hautiere. Measurement of Visibility Conditions with Traffic Cameras. [Research Report] IFSTTAR - Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux. 2017, 9p. ⟨hal-02504366⟩
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