Normalization of inductive vehicle detector outputs
First Claim
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1. A method for normalizing lane occupancy, said method comprising the steps of:
- a) measure a speed of a vehicle with an inductive vehicle detector;
b) measure an on-time for said vehicle crossing a wire loop sensor of said inductive vehicle detector c) determine an inductive length of said vehicle from said measured speed; and
d) compute a normalized on-time by subtracting a longitudinal length of said wire loop sensor from said inductive length and dividing the difference by said measured speed.
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Abstract
Methods for a determining a normalized lane occupancy and for monitoring signal quality for a vehicle detection system. Such methods include, in one embodiment, measuring a speed of a vehicle with an inductive vehicle detector, measuring an on-time for the vehicle crossing a wire loop sensor of the inductive vehicle detector, determining an inductive length of the vehicle from the measured speed, and computing a normalized on-time by subtracting a longitudinal length of the wire loop sensor from the inductive length and dividing the difference by the measured speed.
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Citations
7 Claims
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1. A method for normalizing lane occupancy, said method comprising the steps of:
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a) measure a speed of a vehicle with an inductive vehicle detector;
b) measure an on-time for said vehicle crossing a wire loop sensor of said inductive vehicle detector c) determine an inductive length of said vehicle from said measured speed; and
d) compute a normalized on-time by subtracting a longitudinal length of said wire loop sensor from said inductive length and dividing the difference by said measured speed. - View Dependent Claims (2, 3)
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4. A method for monitoring signal quality for a vehicle detection system, said method comprising the steps of:
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a) measuring a baseline noise level of a series of inductive vehicle signatures on a first detector;
b) avoiding a second detector having a frequency that is identical to an operating frequency of said first detector by selecting said operating frequency having a relatively low baseline noise level;
c) automatically setting a detection threshold to an optimal level to minimize false detections and maximize real detections;
d) measuring a vehicle detector signal level;
e) measuring a quality of a recent history of vehicle detection events; and
f) when the quality of said recent history of vehicle detection events falls below a pre-determined threshold, re-evaluating a plurality of operating conditions of said detector and re-configuring for a more favorable signal-to-noise ratio. - View Dependent Claims (5, 6)
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7. A method for determining a normalized lane occupancy for a vehicle detection system, said method comprising the steps of:
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a) measuring a speed and an inductive length of a vehicle as a function of vehicle speed, and a loop detector on-time whereby said inductive length equals said speed multiplied by said loop detector on-time;
b) subtracting a longitudinal dimension of a wire loop from said inductive length;
c) computing a normalized on-time wherein said normalized on-time equals said inductive length minus said longitudinal dimension of said inductive loop, all divided by said speed; and
d) measuring a total time corresponding to a measurement period;
whereby said normalized lane occupancy is reported as a percentage of said normalized on-time divided by said total time.
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Specification