The Study On Visibility Monitoring And Speed Warning System On The Freeway

The obviously decreased visibility is one of the main incentives that traffic accidents occur on the highway in fog weather at present.Serious accidents have often occurred in fog conditions due to vehicles' high speed which caused huge economic losses and personal injury.Aiming at these problems,this paper presents a specific design of visibility monitoring and limited speed warning system on highway.First,the paper designs a fog status monitoring circuit which mainly uses the forward scatting visibility detection method which achieves a higher precision real-time monitoring result of the highway visibility.Second,the controlling unit computers the highest speed by the model of visibility-highest speed and then displays the highest speed on the LED to warn the drivers.The paper uses an adjustable digital infrared light power to improve detection sensitivity of low visibility in a high enough SNR in the hardware circuit design.The paper also filters out the interference of the background light by the digital filter algorithm of difference method and removing extreme mean filter method.Furthermore,the paper eliminates the impact of temperature drift of the photo-electricity testing parts by temperature compensation algorithm.