초록 ▼

Traffic is monitored in individual lanes of a roadway as to vehicle count or presence, speed and direction of movement by mounting a microphone array high above the road surface, digitizing the output signals of the microphones, filtering, beamforming and storing the digitized signals to provide sep

Traffic is monitored in individual lanes of a roadway as to vehicle count or presence, speed and direction of movement by mounting a microphone array high above the road surface, digitizing the output signals of the microphones, filtering, beamforming and storing the digitized signals to provide separate power histories for separate locations in individual lanes. These power histories are then analyzed to provide vehicle movement data for each lane.

대표청구항 ▼

[ We claim:] [1.] A passive traffic monitoring system, comprising:a) a microphone array including a plurality of microphones spaced from one another, said array being positioned to have a field of view covering a traffic area to be monitored;b) each of said microphones producing a first signal repre

[ We claim:] [1.] A passive traffic monitoring system, comprising:a) a microphone array including a plurality of microphones spaced from one another, said array being positioned to have a field of view covering a traffic area to be monitored;b) each of said microphones producing a first signal representative of sound impinging on said microphone;c) a filter arranged to produce second signals containing only those components of said first signals which lie within at least one predetermined frequency range associated with vehicles in said traffic area;d) a beamformer arranged to combine said second signals so as to produce third signals representative of sound power reaching said microphones from selected predetermined locations within said traffic area;e) a power history generator arranged to store said third signals and to generate therefrom a power history with respect to time for each of said locations; andf) an analyzer arranged to analyze said power histories and to produce therefrom fourth signals representative of vehicle movement parameters at said locations.