Validation checking in traffic monitoring equipment
First Claim
1. In traffic monitoring equipment, apparatus for validation checks in the equipment for checking correctness of a sequence of impulses derived from the passage of vehicles over sensors where the sensors are selected from the group consisting of cables, sensor pads magnetic loop detectors, optical sensors, and pneumatic tube sensors, which apparatus comprises means for comparing a sequence of impulses with a predetermined sequence for the impulses, means coupled to said means for comparing for rejecting the sequence of impulses if it does not agree with the predetermined sequence for the impulses and means coupled to said means for rejecting for generating an error signal if impulses generated by said sensors due to passage of vehicles over said sensors are rejected on one of a regular and repeated basis.
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Accused Products
Abstract
Traffic monitoring equipment including traffic speed measuring equipment has a signal validation facility incorporated to enhance reliability of the equipment. This facility permits the monitoring operation, for example speed measurement, to proceed only if the validation is positive, if negative the operation is aborted and/or a warning signal or shutdown is activated. Validation is made of pulse sequence, pulse strength, radio frequency interference, insulation breakdown, cable integrity (where cables are used) and the like.
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Citations
9 Claims
- 1. In traffic monitoring equipment, apparatus for validation checks in the equipment for checking correctness of a sequence of impulses derived from the passage of vehicles over sensors where the sensors are selected from the group consisting of cables, sensor pads magnetic loop detectors, optical sensors, and pneumatic tube sensors, which apparatus comprises means for comparing a sequence of impulses with a predetermined sequence for the impulses, means coupled to said means for comparing for rejecting the sequence of impulses if it does not agree with the predetermined sequence for the impulses and means coupled to said means for rejecting for generating an error signal if impulses generated by said sensors due to passage of vehicles over said sensors are rejected on one of a regular and repeated basis.
- 3. In traffic monitoring equipment, apparatus for validation checks in the equipment, for monitoring signal strength of an impulse derived from the passage of a vehicle over a sensor, said sensor being selected from the group consisting of cables, sensor pads, magnetic loop detectors, optical sensors and, pneumatic tube sensors, which apparatus comprises detectors for detecting and measuring an impulse derived from the passage of a vehicle over said sensor, means for providing A reference signal and a comparator connected to the detector and to said means for providing a reference signal for determining an attainment by the impulse of a first value which is offset from a reference level provided by said means for providing a reference signal before the impulse is passed by a further connection to impulse processing equipment for traffic monitoring purposes.
- 5. In traffic monitoring equipment, generating an impulse, derived from passage of vehicles over sensors, said monitoring equipment being operated in the presence of a naturally occurring EMI level, apparatus for validation checks in the equipment which comprises structure for performing an electro-magnetic interference (EMI) check, which structure is connected to structure selected from the group consisting of a conventional antenna and a transformer coupling to external cables, the EMI checking structure comprising a barring means for disallowing use of said impulse from a traffic monitoring sensor by the monitoring equipment for traffic monitoring purposes if an EMI level exceeds a predetermined amplitude.
- 7. In traffic monitoring equipment including sensors coupled to the equipment by cables having a capacitance and extending across a road or other surface for passage of vehicles, apparatus for validation checks of the equipment, said validation apparatus comprising capacitance monitoring means for monitoring said capacitance of the cables said monitoring means having detection means selected from the group consisting of means for detection of frequency changes, means for detection of phase changes, and means for detection of changes in natural frequency and ringing of the cable, said detection means determining changes in cable capacitance by utilizing said cable as a capacitive element in a reactive measurement circuit.
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9. Traffic monitoring equipment which comprises traffic detectors wherein said detectors are selected from the group of detectors consisting of cables, detector pads, magnetic loop detectors, optical systems and pneumatic tube systems;
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at least one validation apparatus connected to the equipment wherein said validation apparatus is selected from the group consisting of signal strength validation means, sequence checking means, capacitance checking means, electromagnetic interference checking means for validating an output of said detectors as presenting valid data for use in traffic monitoring measurements;
which equipment further comprises computing means coupled to an output of said validation apparatus for performing traffic monitoring measurements and output means coupled to an output of said computing means and selected from the group consisting of display means, data recording means and a camera recording means for presenting the measurements to a user;means for submitting impulses from the detectors resulting from passage of vehicles to said validation apparatus and for coupling impulses validated as presenting valid data for traffic monitoring measurements to said computing means and for sending a computed result to said output means.
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Specification