Traffic monitoring using optical sensors

Patent metadata

Field	Value
Publication number	US-11823567-B2
Application number	US-202117393986-A
Country	US
Kind code	B2
Filing date	Aug 4, 2021
Priority date	Aug 4, 2021
Publication date	Nov 21, 2023
Grant date	Nov 21, 2023

Abstract

A system includes a sensor network comprising at least two optical fibers coupled to a pavement. Each optical fiber includes one or more optical sensors installed a predetermined distance from one or more adjacent optical fibers. The one or more optical sensors are configured to produce a wavelength shift signal. A processor is configured to determine one or both of one or more attributes of one or more objects travelling on the pavement and a traffic condition of the pavement based on the wavelength shift signal. A transmitter is configured to transmit the one or more attributes to a predetermined location.

First claim

What is claimed is:

1. A system, comprising:
a sensor network comprising at least two optical fibers coupled to a pavement, each optical fiber comprising one or more optical sensors installed a predetermined distance from one or more adjacent optical fibers, the one or more optical sensors configured to produce a wavelength shift signal;
a processor configured to:
determine one or both of one or more attributes of one or more objects travelling on the pavement and a traffic condition of the pavement based on the wavelength shift signal, the one or more attributes comprising a speed of the one or more objects, the speed of the one or more objects determined by:
aggregating data from two or more of the optical sensors of the one or more optical sensors; and
determining one or both of a median and a mean of the aggregated data; and

a transmitter configured to transmit one or both of the one or more attributes and the traffic condition to a predetermined location.

2. The system of claim 1 , wherein the processor is further configured to detect one or more of entry and exit of an object from a sensing zone.

3. The system of claim 1 , wherein the one or more attributes comprise one or more of a direction of travel, a number of axles of the one or more objects, a distance between axles of the one or more objects, a group of axles of the one or more objects, a lane of traffic that the one or more objects are travelling in, and a weight per axle for the one or more objects.

4. The system of claim 3 , wherein the processor is configured to aggregate the one or more attributes to determine one or more of an object classification, a road occupancy, and a traffic volume of the pavement.

5. The system of claim 1 , wherein the speed of the one or more objects is determined using a single sensor pair.

6. The system of claim 1 , wherein the speed of the one or more objects is determined using correlation between a first wavelength shift signal received from sensors disposed on a first optical fiber and a second wavelength shift signal received from sensors disposed on a second optical fiber.

7. The system of claim 1 , wherein the speed of the one or more objects is determined using a time shift of wavelength shift peaks of the wavelength shift signal.

8. The system of claim 1 , wherein the at least two optical fibers are installed parallel to each other.

9. The system of claim 1 , wherein the processor is further configured to detect lane straddling of the one or more objects based on the wavelength shift signal.

10. The system of claim 1 , wherein the processor is further configured to issue an alert based on the wavelength shift signal.

11. The system of claim 1 , wherein the one or more objects comprise one or more of vehicles and pedestrians.

12. The system of claim 1 , wherein the pavement comprises one or more of a walkway and a road.

13. The system of claim 1 , wherein the wavelength shift signal comprises a strain signal.

14. The system of claim 1 , wherein the processor is configured to:
determine the one or both of the one or more attributes of the one or more objects travelling on the pavement based on at least two disparate methods; and
merge results from the at least two disparate methods.

15. A method, comprising:
receiving a wavelength shift signal from a plurality of optical sensors coupled to a pavement, the plurality of optical sensors disposed on at least two optical fibers, each optical fiber disposed a predetermined distance from at least one other optical fiber;
determining one or both of one or more attributes of one or more objects travelling on the pavement and a traffic condition based on the wavelength shift signal, the one or more attributes comprising a speed of the one or more objects, the speed of the one or more objects determined by:
aggregating data from two or more of the optical sensors of the one or more optical sensors; and
determining one or both of a median and a mean of the aggregated data; and

transferring one or both of the one or more attributes and the traffic condition to a predetermined location.

16. The method of claim 15 , further comprising detecting one or more of entry and exit of an object from a sensing zone.

17. The method of claim 15 , wherein the one or more attributes comprise one or more of a direction of travel, a number of axles of the one or more objects, a distance between axles of the one or more objects, a group of axles of the one or more objects, a lane of traffic that the one or more objects are travelling in, and a weight per axle for the one or more objects.

18. The method of claim 17 , further comprising aggregating the one or more attributes to determine one or more of an object classification, a road occupancy, and a traffic volume of the pavement.

19. The method of claim 17 , further comprising determining the speed of the one or more objects using correlation between a first wavelength shift signal received from sensors disposed on a first optical fiber and a second wavelength shift signal received from sensors disposed on a second optical fiber.

20. The method of claim 17 , further comprising determining the speed of the one or more objects using a time shift of wavelength shift peaks of the wavelength shift signal.

Assignees

• Palo Alto Res Ct Inc
• Xerox Corp

Inventors

• Yu Hong
• Chen Qiushu
• Kiesel Peter
• Raghavan Ajay
• Yan Jin
• Arakaki Kyle

Classifications

• G08G1/0116 Primary

  from roadside infrastructure, e.g. beacons · CPC title

• E01F11/00

  {Road engineering aspects of} Embedding pads or other sensitive devices in paving or other road surfaces {, e.g. traffic detectors, vehicle-operated pressure-sensitive actuators, devices for monitoring atmospheric or road conditions}(pressure-sensitive elements G01L; traffic control systems G08G) · CPC title

• G01D5/353

  influencing the transmission properties of an optical fibre · CPC title

• G08G1/0133

  for classifying traffic situation · CPC title

• G08G1/02

  using treadles built into the road (pads or other sensitive devices responsive to passage of vehicles E01F11/00) · CPC title