Acoustic sensor system for vehicle detection and multi-lane highway monitoring

摘要

A novel multi-lane traffic monitoring system is based on detecting the acoustic signals motor vehicles create and radiate during operation. The system comprises an array of electro-acoustic sensors for converting impinging acoustic wavefronts to analog electrical signals; a circuit to acquire, perform signal frequency component discrimination, and digitize the electrical signals at the electro-acoustic sensor array output; a circuit to perform effective spatial discrimination in the up/down road direction and in the cross-road direction in real time; a circuit to perform vehicle detection for individual lanes and to estimate or measure pertinent parameters associated with each vehicle detection from each traveled lane; and a circuit to compute for each lane, pertinent traffic flow parameters from vehicle parameters for the purpose of providing a transportation system interface. In accordance with another embodiment, a circuit is provided to automatically scan for acoustic sources in the cross-road direction and to automatically identify each highway lane direction relative to the physical electro-acoustic sensor array orientation. In accordance with still another embodiment, a circuit is provided via signal frequency component discrimination and signal processing to create, from a single physical sensor, two vehicle detection zones within each highway lane, wherein a smaller detection zone is located inside a larger detection zone. A circuit is also provided to measure the time between initial vehicle detection in the larger (outer) detection zone and initial vehicle detection in the smaller (inner) detection zone, wherein vehicle speed is determined from the initial detection time difference. In accordance with yet another embodiment, a circuit is provided to measure the relative position of the sound radiated from each of a vehicle's tires and determine vehicle type classification associated with each vehicle detection and with each measured vehicle speed.