Vehicle-detecting unit for use with electronic parking meter

• US 6,229,455 B1
• Filed: 03/17/1999
• Issued: 05/08/2001
• Est. Priority Date: 01/15/1999
• Status: Expired due to Fees

• Current Assignee: Intelligent Devices Inc. (Heico Corporation)
• Original Assignee: Intelligent Devices Inc. (Heico Corporation)
• Inventors: Saar, David A., Yost, Vincent G.
• Primary Examiner(s): Wu, Daniel J.
• Assistant Examiner(s): Huang, Sihong
• Application Number:
  US09/270,548
• Time in Patent Office: 783 Days
• Field of Search: 340/942, 340/943, 340/933, 340/932.2, 340/935-937
• US Class Current: 340/943
• CPC Class Codes: G07F 17/24 for parking meters
• CPC Class Codes: G07F 17/246 provided with vehicle proximity-detectors detecting hidden masses, e.g. metal detectors, G01V, e.g. G01V3/00; proximity switches per se H03K17/00; traffic control systems G08G1/00

Abstract

A vehicle detector unit and detection method for use with an electronic parking meter for providing the electronic parking meter with the ability to reliably detect the presence or absence of a vehicle in any existing corresponding parking space, independent of the surrounding environment, while using a minimum of power.

Claims

1. A vehicle detector unit for use with an electronic parking meter for detecting the presence or absence of a vehicle in a corresponding parking space, said unit comprising:

a first signal emitting sensor positioned adjacent the corresponding parking space for transmitting a first signal towards the parking space in a first direction and for receiving a reflection of said first signal;

a second signal emitting sensor positioned adjacent the corresponding parking space for transmitting a second signal towards the parking space in a second direction different from said first direction and for receiving a reflection of said second signal;

processing means coupled to said first and second signal-emitting sensors for processing said reflections of said first and second signals to determine if a vehicle is positioned in the corresponding parking space, said processor means coupled to the electronic parking meter for communicating the presence or absence of a vehicle in the corresponding parking space to the electronic parking meter;

means for storing a first reflected signal corresponding to an empty parking space for said first signal-emitting sensor and a second reflected signal corresponding to the empty parking space for said second signal-emitting sensor, said storing means being coupled to said processing means; and

a tamper detection system, said tamper detection system being coupled to said processing means for detecting inadvertent or intentional tampering of said first or second signal-emitting sensors.

2. The vehicle detector unit of claim 1 wherein tamper detection system comprises an optical signal emitter and detector coupled to said processor means, said optical signal emitter and detector being positioned toward the corresponding parking space.

3. The vehicle detector unit of claim 2 wherein said means for storing includes a reflected signal corresponding to an unobstructed path towards the corresponding parking space for said optical signal emitter.

4. The vehicle detector unit of claim 2 wherein the optical signal emitter and detector comprise an infrared light emitting diode and an infrared photodetector.

5. The vehicle detector unit of claim 1 further comprising a housing having a side which is positioned towards the corresponding parking space, said side including said first and second signal-emitting sensors at a first angular orientation and a second angular orientation, respectively, said first angular orientation being in the range of 0-45 degrees away from a vertical plane through said side and said second angular orientation being in the range of 0-45 degrees in the opposite direction of said first angular orientation from said vertical plane.

6. The vehicle detector unit of claim 5 wherein said first and second signal-emitting sensors are positioned at an angular orientation in the range of −

30 to 30 degrees from a horizontal plane.

7. The vehicle detector unit of claim 1 further comprising a housing having a side which is positioned towards the corresponding parking space, said side including said first and second signal-emitting sensors at a first angular orientation and a second angular orientation, respectively, said first angular orientation being 22½

degrees away from a vertical plane through said side and said second angular orientation being 22½

degrees in the opposite direction of said first angular orientation from said vertical plane.

8. The vehicle detector unit of claim 7 wherein said first and second signal-emitting sensors are positioned downward from a horizontal plane at an angular orientation of 12 degrees.

9. The vehicle detector unit of claim 8 further comprising means for storing a first reflected signal corresponding to an empty parking space for said first signal-emitting sensor and a second reflected signal corresponding to the empty parking space for said second signal-emitting sensor, said storing means being coupled to said processing means.

10. The vehicle detector unit of claim 9 further comprising a tamper detection system, said tamper detection system coupled to said processing means for detecting inadvertent or intentional tampering of said first or second signal-emitting sensors.

11. The vehicle detector unit of claim 10 wherein tamper detection system comprises an optical signal emitter and detector coupled to said processor means, said optical signal emitter and detector being positioned toward the corresponding parking space.

12. The vehicle detector unit of claim 11 wherein said optical signal emitter and emitter are positioned between said first and second signal-emitting means and wherein said emitter and detector are positioned at an angular orientation in the range of −

30 to 30 degrees from said horizontal plane.

13. The vehicle detector unit of claim 11 wherein said optical signal emitter and emitter are positioned between said first and second signal-emitting means and wherein said emitter and detector are positioned downward from said horizontal plane at said angular orientation of 12 degrees.

14. The vehicle detector unit of claim 11 wherein said means for storing includes a reflected signal corresponding to an unobstructed path towards the corresponding parking space for said optical signal emitter.

15. A vehicle detector unit for use with an electronic parking meter for detecting the presence or absence of a vehicle in a corresponding parking space, said unit comprising:

a first signal emitting sensor positioned adjacent the corresponding parking space for transmitting a first signal towards the parking space in a first direction and for receiving a reflection of said first signal;

a second signal emitting sensor positioned adjacent the corresponding parking space for transmitting a second signal towards the parking space in a second direction different from said first direction and for receiving a reflection of said second signal; and

processing means coupled to said first and second signal-emitting sensors for processing said reflections of said first and second signals to determine if a vehicle is positioned in the corresponding parking space, said processor means coupled to the electronic parking meter for communicating the presence or absence of a vehicle in the corresponding parking space to the electronic parking meter;

a third signal-emitting sensor, positioned in between said first and second signal-emitting sensors, for transmitting a third signal towards the parking space in a third direction, different from said first and second directions and for receiving a reflection of said third signal, said third signal-emitting means being coupled to said processing means;

wherein said processing means processes said reflection of said third signal, in addition to processing said reflections of said first and second signals, to determine if a vehicle is positioned in the corresponding parking space;

said first direction being towards a front portion of the corresponding parking space, said second direction being towards a back portion of the corresponding parking space and said third direction being towards a center portion of the corresponding parking space;

means for storing a first reflected signal corresponding to an empty parking space for said first signal-emitting sensor, a second reflected signal corresponding to the empty parking space for said second signal-emitting sensor and a third reflected signal corresponding to the empty parking space for said third signal-emitting sensor, said storing means being coupled to said processing means; and

a tamper detection system, said tamper detection system being coupled to said processing means for detecting inadvertent or intentional tampering of said first, second and third signal-emitting sensors.

16. The vehicle detector unit of claim 15 wherein tamper detection system comprises an optical signal emitter and detector coupled to said processor means, said optical signal emitter and detector being positioned toward the corresponding parking space and positioned above said third signal-emitting sensor.

17. The vehicle detector unit of claim 16 wherein said means for storing includes a reflected signal corresponding to an unobstructed path towards the corresponding parking space for said optical signal emitter.

18. The vehicle detector unit of claim 15 further comprising a housing having a side which is positioned towards the corresponding parking space, said side including said first and second signal-emitting sensors at a first angular orientation and a second angular orientation, respectively, said first angular orientation being in the range of 0-45 degrees away from a vertical plane through said side and said second angular orientation being in the range of 0-45 degrees in the opposite direction of said first angular orientation from said vertical plane.

19. The vehicle detector unit of claim 15 further comprising a housing having a side which is positioned towards the corresponding parking space, said side including said first and second signal-emitting sensors at a first angular orientation and a second angular orientation, respectively, said first angular orientation being 22½

degrees away from a vertical plane through said side and said second angular orientation being 22½

degrees in the opposite direction of said first angular orientation from said vertical plane.

20. The vehicle detector unit of claim 19 wherein said first, second and third signal-emitting sensors are positioned at an angular orientation in the range of −

30 to 30 degrees from a horizontal plane.

21. The vehicle detector unit of claim 19 wherein said first, second and third signal-emitting sensors are positioned downward from a horizontal plane at an angular orientation of 12 degrees.

22. The vehicle detector unit of claim 19 further comprising means for storing a first reflected signal corresponding to an empty parking space for said first signal-emitting sensor, a second reflected signal corresponding to the empty parking space for said second signal-emitting sensor and a third reflected signal corresponding to the empty parking space for said third signal-emitting sensor, said storing means being coupled to said processing means.

23. The vehicle detector unit of claim 22 further comprising a tamper detection system, said tamper detection system coupled to said processing means for detecting inadvertent or intentional tampering of said first, second or third signal-emitting sensors.

24. The vehicle detector unit of claim 23 wherein tamper detection system comprises an optical signal emitter and detector coupled to said processor means, said optical signal emitter and detector being positioned toward the corresponding parking space.

25. The vehicle detector unit of claim 24 wherein said optical signal emitter and emitter are positioned above said third signal-emitting means and wherein said emitter and detector are positioned at an angular orientation in the range of −

30 to 30 degrees from said horizontal plane.

26. The vehicle detector unit of claim 24 wherein said optical signal emitter and emitter are positioned above said third signal-emitting means and wherein said emitter and detector are positioned downward from said horizontal plane at said angular orientation of 12 degrees.

27. The vehicle detector unit of claim 26 wherein said means for storing includes a reflected signal corresponding to an unobstructed path towards the corresponding parking space for said optical signal emitter.

28. A method for detecting a vehicle at a parking space, said method comprising the steps of:

(a) positioning two signal-emitting sensors adjacent the parking space, said sensors being oriented toward the parking space;

(b) alternately activating said two signal-emitting sensors, at a first predetermined interval, each of said two signal-emitting sensors both emitting signals and receiving reflections of said emitted signals to form a first set of reflected signals;

(c) processing each of said reflected signals to determine if the amplitude of at least one of said first set of reflected signals is above a predetermined threshold;

(d) alternately activating said two signal-emitting sensors at a second shorter predetermined interval to both emit signals and to receive reflections of said emitted signals to form a second set of reflected signals whenever the amplitude of at least one reflected signal of said first set of reflected signals exceeds said predetermined threshold;

(e) processing each of said second set of reflected signals to determine if a predetermined number of consecutive reflected signals in said second set comprise amplitudes that exceed said predetermined threshold for establishing the presence of a vehicle in the parking space; and

(f) transmitting a signal indicative of a vehicle detected.

29. The method of claim 28 wherein said step of positioning two signal-emitting sensors adjacent the parking space comprises:

(a) clearing the parking space on a one-time basis to form an empty parking space;

(b) activating each of said two signal-emitting sensors alternately at said first predetermined interval to establish a baseline signal for each of said two signal-emitting sensors on a one-time basis;

(c) storing each of said respective baseline signals in a storage means for use in said step of processing each of said second set of reflected signals.

30. The method of claim 29 further comprising the steps of:

(a) selecting one of said two signal-emitting sensors that received a signal in said second set of reflected signals having the highest amplitude; and

(b) activating only said selected one of said two signal-emitting sensors at said first predetermined interval to form a third set of reflected signals.

31. The method of claim 30 further comprising the steps of:

(a) alternately activating said two sensors at a third predetermined interval whenever said third set of signals disappear to determine if a parked vehicle has departed;

(b) terminating the transmission of said signal indicative of a vehicle detected whenever said two sensors experience a predetermined number of consecutive no receipt of reflected signals from said alternate activation of said two sensors at said third predetermined interval.

32. The method of claim 31 further comprising the steps of:

(a) positioning an optical signal sensor adjacent the parking space and orienting it toward the parking space;

(b) activating said optical signal sensor on a one-time basis while the parking space is empty to obtain a baseline signal for said optical signal-emitting sensor;

(c) storing said optical sensor baseline signal in a storage means;

(d) activating said optical sensor at said first predetermined interval to generate optical signal reflections whenever said third set of signals disappear;

(e) comparing said optical signal reflections to said optical sensor baseline to determine if a tamper condition is present; and

(f) transmitting a signal indicative of a tamper condition whenever the amplitude of said optical signal reflections is greater than said optical sensor baseline.

33. The method of claim 32 wherein said optical sensor comprises an infrared emitter and an infrared detector.

34. The method of claim 30 further comprising the steps of:

(a) alternately activating said two sensors at a third predetermined interval whenever said third set of signals disappear to determine if a parked vehicle has departed;

(b) monitoring the change in amplitude of any reflected signals from said alternate activation of said two sensors at said third predetermined interval that correspond to a predetermined range away from said at least two signal-emitting sensors; and

(c) transmitting a signal indicative of a tamper condition whenever said change in amplitude is greater than a second predetermined threshold or less than a third predetermined threshold.

35. The method of claim 28 wherein said step of positioning two signal-emitting sensors comprises orienting said at least two signal-emitting sensors in opposite directions at an angle in the range of 0 to 45 degrees from a vertical plane.

36. The method of claim 28 wherein said step of positioning two signal-emitting sensors comprises orienting said at least two signal-emitting sensors in opposite directions at an angle of 22½

degrees from a vertical plane.

37. The method of claim 36 wherein said step of positioning a third signal-emitting sensor between said two signal-emitting sensors comprises orienting all of said signal-emitting sensors at an angular orientation in the range of −

30 to 30 degrees from a horizontal plane.

38. The method of claim 36 wherein said step of positioning a third signal-emitting sensor between said two signal-emitting sensors comprises orienting all of said signal-emitting sensors downward at an angle of 12 degrees from a horizontal plane.

39. The method of claim 36 wherein said step of positioning two signal-emitting sensors comprises orienting said two signal-emitting sensors at an angular orientation in the range of −

30 to 30 degrees from a horizontal plane.

40. The method of claim 36 wherein said step of positioning two signal-emitting sensors comprises orienting said two signal-emitting sensors downward at an angle of 12 degrees from a horizontal plane.

41. The method of claim 28 further comprising the step of positioning a third signal-emitting sensor between said two signal-emitting sensors.

42. The method of claim 41 further comprising the steps of:

(a) modifying said step of alternately activating said two signal-emitting sensors by alternately;

(1) activating one of said two signal-emitting sensors;

(2) activating said third signal-emitting sensor;

(3) activating the other one of said two signal-emitting sensors;

(4) activating said third signal-emitting sensor;

(5) repeating sensor sequencing steps (1)-(4) at said first predetermined interval to generate said first set of reflected signals; and

(b) modifying said step of alternately activating said two signal emitting sensors at said second shorter predetermined interval by alternately and sequentially activating said three sensors at said second shorter predetermined interval to form said second set of reflected signals.

43. The method of claim 42 wherein said step of positioning a third signal-emitting sensor adjacent the parking space comprises:

(a) clearing the parking space on a one-time basis to form an empty parking space;

(b) activating each of said three signal-emitting sensors alternately at said first predetermined interval to establish a baseline signal for each of said three signal-emitting sensors on a one-time basis;

(c) storing each of said respective baseline signals in a storage means for use in said step of processing each of said second set of reflected signals.

44. The method of claim 43 further comprising the steps of:

(a) selecting one of said three signal-emitting sensors that received a signal in said second set of reflected signals having the highest amplitude; and

(b) activating only said selected one of said three signal-emitting sensors at said first predetermined interval to form a third set of reflected signals.

45. The method of claim 44 further comprising the steps of:

(a) alternately activating said three sensors at a third predetermined interval whenever said third set of signals disappear to determine if a parked vehicle has departed;

(b) terminating the transmission of said signal indicative of a vehicle detected whenever said three sensors experience a predetermined number of consecutive no receipt of reflected signals from said alternate activation of said three sensors at said third predetermined interval.

46. The method of claim 45 further comprising the steps of:

(a) positioning an optical signal sensor adjacent the parking space and orienting it toward the parking space;

(b) activating said optical signal sensor on a one-time basis while the parking space is empty to obtain a baseline signal for said optical signal-emitting sensor;

(c) storing said optical sensor baseline signal in a storage means;

(d) activating said optical sensor at said first predetermined interval to generate optical signal reflections whenever said third set of signals disappear;

(e) comparing said optical signal reflections to said optical sensor baseline to determine if a tamper condition is present; and

(f) transmitting a signal indicative of a tamper condition whenever the amplitude of said optical signal reflections is greater than said optical sensor baseline.

47. The method of claim 44 further comprising the steps of:

(a) alternately activating said three sensors at a third predetermined interval whenever said third set of signals disappear to determine if a parked vehicle has departed;

(b) monitoring the change in amplitude of any reflected signals from said alternate activation of said three sensors at said third predetermined interval that correspond to a predetermined range away from said three signal-emitting sensors; and

(c) transmitting a signal indicative of a tamper condition whenever said change in amplitude is greater than a second predetermined threshold or less than a third predetermined threshold.

48. The method of claim 41 wherein said step of positioning a third signal-emitting sensor between said two signal-emitting sensors comprises orienting said two signal-emitting sensors in opposite directions at an angle in the range of 0 to 45 degrees from a vertical plane.

49. The method of claim 41 wherein said step of positioning a third signal-emitting sensor between said two signal-emitting sensors comprises orienting said two signal-emitting sensors in opposite directions at an angle of 22½

degrees from a vertical plane.

50. The method of claim 28 wherein said first predetermined interval comprises one second.

51. The method of claim 28 wherein said second predetermined interval comprises 50 msec.

52. The method of claim 28 wherein said predetermined threshold is the noise level of the parking space.

53. The method of claim 28 wherein the predetermined number of consecutive reflected signals is six.