System and method of vehicle detection
First Claim
1. Vehicle sensor system for detecting vehicles having predetermined length and height profiles and at least a predetermined minimum length along a direction of movement through a vehicular traffic lane, which comprises(a) first and second ultrasonic transmitting units spaced from each other along the traffic lane a distance less than said predetermined minimum length, said first transmitting unit being arranged upstream of the direction of traffic and said second transmitting unit being arranged downstream of the direction of traffic, each of said transmitting units being mounted to transmit ultrasonic signals downwardly in the direction of a vehicle moving through the lane;
- (b) first and second ultrasonic receiving units associated with said first and second transmitting units, respectively, and arranged above the traffic lane for receiving the ultrasonic signals emitted by the associated ultrasonic transmitting unit and reflected from the road surface or the ground and from successive portions of the vehicle travelling through the traffic lane;
(c) height determining means for determining the heights of surfaces from which said reflected ultrasonic signals have been reflected and received by each of said ultrasonic receiving units; and
(d) processor means for verifying absolute and relative measured heights and discounting spurious data, and issuing a vehicle detect signal when a determination has been made that the detected heights in both said ultrasonic receiving units conform with each other and conform with said predetermined vehicle length and height profiles of the vehicles.
1 Assignment
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Accused Products
Abstract
A method for detecting vehicles includes two ultrasonic overhead detectors arranged along a lane or path of travel of a car through an access gate or entrance. The detectors measure the heights of the hood, roof and trunk of the car as it moves past the detectors. Software is used to compare the measured quantities with pre-established vehicle profiles. The method, and the associated hardware and software, can be used to count vehicles, classify vehicles as well as operate peripheral devices such as traffic lights, gates and the like.
81 Citations
29 Claims
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1. Vehicle sensor system for detecting vehicles having predetermined length and height profiles and at least a predetermined minimum length along a direction of movement through a vehicular traffic lane, which comprises
(a) first and second ultrasonic transmitting units spaced from each other along the traffic lane a distance less than said predetermined minimum length, said first transmitting unit being arranged upstream of the direction of traffic and said second transmitting unit being arranged downstream of the direction of traffic, each of said transmitting units being mounted to transmit ultrasonic signals downwardly in the direction of a vehicle moving through the lane; -
(b) first and second ultrasonic receiving units associated with said first and second transmitting units, respectively, and arranged above the traffic lane for receiving the ultrasonic signals emitted by the associated ultrasonic transmitting unit and reflected from the road surface or the ground and from successive portions of the vehicle travelling through the traffic lane; (c) height determining means for determining the heights of surfaces from which said reflected ultrasonic signals have been reflected and received by each of said ultrasonic receiving units; and (d) processor means for verifying absolute and relative measured heights and discounting spurious data, and issuing a vehicle detect signal when a determination has been made that the detected heights in both said ultrasonic receiving units conform with each other and conform with said predetermined vehicle length and height profiles of the vehicles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of detecting vehicles having predetermined length and height profiles and at least a predetermined minimum length along a direction of movement through a vehicular traffic lane, comprising the steps of
(a) transmitting ultrasonic signals downwardly from two positions spaced from each other a predetermined distance above the traffic lane less than said predetermined minimum length; -
(b) receiving ultrasonic signals at each of said positions reflected from the road surface or the ground and from successive portions of a vehicle travelling through the traffic lane; (c) determining the heights of reflecting surfaces at said two positions based on said received ultrasonic signals; (d) verifying said heights and discounting spurious data; and (e) issuing a vehicle detect signal when a determination has been made that the detected heights of both said positions conform to each other and with said predetermined vehicle length and height profiles. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification