Non-intrusive traffic monitoring system
First Claim
1. A traffic monitoring system comprising a non-intrusive lane monitor, said lane monitor comprising first and second laser channels, a user interface, and a programmable controller in communication with said first and second laser channels and said user interface, wherein:
- said first laser channel comprises a first laser source and a first laser receiver;
said first laser source is configured to generate a first pulsed laser signal along a first laser axis;
said first laser receiver is configured to detect individual reflected laser pulses from said first pulsed laser signal;
said second laser channel comprises a second laser source and a second laser receiver;
said second laser source is configured to generate a second pulsed laser signal along a second laser axis;
said second laser receiver is configured to detect individual reflected laser pulses from said second pulsed laser signal;
said first laser axis is substantially parallel to said second laser axis;
said first and second laser axes lie substantially in a common horizontal plane;
said first laser axis is offset from said second laser axis in said common horizontal plane by a laser channel offset distance x; and
said programmable controller is configured to;
generate reflected laser pulse count corresponding to reflection of a pulsed laser signal from a target positioned along one of said laser axes, andidentify said reflected signal as a valid or invalid target by comparing said pulse count to a predetermined valid target count.
1 Assignment
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Accused Products
Abstract
A traffic monitoring system including a non-intrusive lane monitor is provided. The lane monitor comprises one or more laser channels, a user interface, and a programmable controller in communication with the laser channels and the user interface. In accordance with one embodiment of the present invention, a pair of laser channels are provided. The first laser axis is substantially parallel to the second laser axis and the first and second laser axes lie substantially in a common horizontal plane. The programmable controller is configured to generate reflected laser pulse count corresponding to reflection of a pulsed laser signal from a target positioned along one of the laser axes and identify the reflected signal as a valid or invalid target by comparing the pulse count to a predetermined valid target count.
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Citations
54 Claims
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1. A traffic monitoring system comprising a non-intrusive lane monitor, said lane monitor comprising first and second laser channels, a user interface, and a programmable controller in communication with said first and second laser channels and said user interface, wherein:
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said first laser channel comprises a first laser source and a first laser receiver; said first laser source is configured to generate a first pulsed laser signal along a first laser axis; said first laser receiver is configured to detect individual reflected laser pulses from said first pulsed laser signal; said second laser channel comprises a second laser source and a second laser receiver; said second laser source is configured to generate a second pulsed laser signal along a second laser axis; said second laser receiver is configured to detect individual reflected laser pulses from said second pulsed laser signal; said first laser axis is substantially parallel to said second laser axis; said first and second laser axes lie substantially in a common horizontal plane; said first laser axis is offset from said second laser axis in said common horizontal plane by a laser channel offset distance x; and said programmable controller is configured to; generate reflected laser pulse count corresponding to reflection of a pulsed laser signal from a target positioned along one of said laser axes, and identify said reflected signal as a valid or invalid target by comparing said pulse count to a predetermined valid target count. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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49. A traffic monitoring system comprising a non-intrusive lane monitor, said lane monitor comprising first and second laser channels, a user interface, and a programmable controller in communication with said first and second laser channels and said user interface, wherein:
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said first laser channel comprises a first laser source and a first laser receiver; said first laser source is configured to generate a first pulsed laser signal along a first laser axis; said first laser receiver is configured to detect individual reflected laser pulses from said first pulsed laser signal; said second laser channel comprises a second laser source and a second laser receiver; said second laser source is configured to generate a second pulsed laser signal along a second laser axis; said second laser receiver is configured to detect individual reflected laser pulses from said second pulsed laser signal; said first laser axis is substantially parallel to said second laser axis; said first and second laser axes lie substantially in a common horizontal plane; said first laser axis is offset from said second laser axis in said common horizontal plane by a laser channel offset distance x; and said programmable controller is configured to generate said first and second laser signals at a pulse repetition frequency PRF of at least about; where v corresponds to an expected average target speed, x corresponds to the channel offset distance and p corresponds to the desired percent precision in the speed determination.
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50. A traffic monitoring system comprising a non-intrusive lane monitor, said lane monitor comprising at least one laser channel, a user interface, and a programmable controller in communication with said laser channel and said user interface, wherein:
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said laser channel comprises a laser source and a laser receiver; said laser source is configured to generate a pulsed laser signal along a laser axis; said laser receiver is configured to detect individual reflected laser pulses from said pulsed laser signal; said laser source is configured to generate pulsed laser signals having a cross sectional beam profile characterized by a minor axis of divergence and a major axis of divergence; and said laser source is configured such that said minor axis of divergence lies in a substantially vertical plane said major axis of divergence lies in a substantially horizontal plane. - View Dependent Claims (51)
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52. A traffic monitoring system comprising a non-intrusive lane monitor, said lane monitor comprising at least one laser channel, a user interface, and a programmable controller in communication with said laser channel and said user interface, wherein:
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said laser channel comprises a laser source and a laser receiver; said laser source is configured to generate a pulsed laser signal along a laser axis; said laser receiver is configured to detect individual reflected laser pulses from said pulsed laser signal; and said programmable controller is configured to; generate reflected laser pulse count corresponding to reflection of a pulsed laser signal from a target positioned along one of said laser axes, and identify said reflected signal as a valid or invalid target by comparing said pulse count to a predetermined valid target count.
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53. A traffic monitoring system comprising a non-intrusive lane monitor, said lane monitor comprising at least one laser channel, a user interface, and a programmable controller in communication with said laser channel and said user interface, wherein:
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said laser channel comprises a laser source and a laser receiver; said laser source is configured to generate a pulsed laser signal along a laser axis; said laser receiver is configured to detect individual reflected laser pulses from said pulsed laser signal; and said programmable controller is configured to generate said first and second laser signals at a pulse repetition frequency sufficient to generate a plurality of reflected pulses as less than 1 inches (2.5 cm) of a target moving at a speed v intercepts one of said pulsed laser signals, said speed v being at least about 55 mph (90 km/h).
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54. A traffic monitoring system comprising a non-intrusive lane monitor, said lane monitor comprising at least one laser channel, at least one constant fraction discrimination circuit, a user interface, and a programmable controller in communication with said laser channel, said constant fraction discrimination circuit, and said user interface, wherein:
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said laser channel comprises a laser source and a laser receiver; said laser source is configured to generate a pulsed laser signal along a laser axis; said laser receiver is configured to detect individual reflected laser pulses from said pulsed laser signal; said laser receiver is in communication with said constant fraction discrimination circuit; said constant fraction discrimination circuit is configured to account for differences in respective rise times of laser pulses reflected from surfaces of differing reflectivity at a common range; and said constant fraction discrimination circuit is configured to combine a detected reflected signal pulse with a delayed, inverted replica to obtain a signal that is substantially independent of pulse amplitude.
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Specification