Portable traffic analyzer

• US 20080117081A1
• Filed: 03/12/2007
• Published: 05/22/2008
• Est. Priority Date: 11/17/2006
• Status: Abandoned Application

• Current Assignee: Vaisala Oyj
• Original Assignee: Vaisala Oyj
• Inventors: Libertino, Angelo, Rae, Thomas Christopher, Radusewicz, Peter Jerome
• Application Number:
  US11/716,934
• Publication Number:
  US 20080117081A1
• Time in Patent Office: Days
• US Class Current: 340/933
• CPC Class Codes: G08G 1/01 Detecting movement of traffic to be counted or controlled G08G1/07 - G08G1/14 take precedence

Abstract

A traffic analyzer for detecting a magnetic permeable mass passing a fixed position includes a calibrated magnetic background memory device, a first magnetic field detector, a second magnetic field detector, a window comparator, and a programmable processor. The first magnetic field detector is operative to detect a change in a magnetic field caused by a magnetic permeable mass passing the magnetic field detector. The window comparator then generates a comparative output of the detected change and a threshold value stored in the calibrated magnetic background memory device. The window comparator then generates a comparative output to place the programmable processor in an active state. The programmable processor is then operative to calculate characteristic data of the magnetic permeable mass using the output from the first and second magnetic field detectors. The characteristic data may be stored in a memory storage device according to a dynamic distribution classification.

Claims

1. A traffic analyzer for detecting a magnetic permeable mass, the traffic analyzer comprising:

a first magnetic field detector operative to produce a first output indicative of a first change in a magnetic field caused by a magnetic permeable mass;

a second magnetic field detector operative to produce a second output indicative of a second change in the magnetic field caused by the magnetic permeable mass, the second magnetic field detector being spaced apart from the first magnetic field detector at a predetermined distance;

a programmable processor operative to receive the first output of the first magnetic field detector and the second output of the second magnetic field detector to produce an output of characteristic data of the magnetic permeable mass, the programmable processor being activated based on a comparison of the first change in the magnetic field and a threshold value; and

,

a memory storage device operative to store the characteristic data output by the programmable processor, the programmable processor storing the characteristic data in the memory storage device according to a dynamic distribution classification.

2. The traffic analyzer of claim 1 where the dynamic distribution classification is based on speed.

3. The traffic analyzer of claim 1 where characteristic data comprises a speed value of the magnetic permeable mass.

4. A traffic analyzer for detecting a magnetic permeable mass passing a fixed position, the traffic analyzer comprising:

a calibrated magnetic background memory device operative to store a threshold value;

a magnetic field detector operative to detect a change in a magnetic field, the change being caused by a magnetic permeable mass, and further operative to produce an analog output indicative of the change in the magnetic field;

a window comparator operative to generate a comparative output where the analog output of the magnetic field detector exceeds the threshold value;

an analog-to-digital converter operative to generate a digital output by sampling the analog output; and

,

a programmable processor operative to output characteristic data based on the digital output, the programmable processor being activated based on the comparative output.

5. The traffic analyzer of claim 4 further comprising:

a signal condition off-amplifier operative to amplify the analog output; and

,

a bandpass filter operative to filter the amplified analog output based on a predetermined frequency, the filtered amplified analog output being used to generate the digital output.

6. The traffic analyzer of claim 4 further comprising a real-time clock operative to calculate a time value based on a pre-determined interval, where the programmable processor is further operative to associate the characteristic data with the calculated time value.

7. The traffic analyzer of claim 4 further comprising memory operative to store the characteristic data output by the programmable processor.

8. The traffic analyzer of claim 7, where the memory is flash memory.

9. The traffic analyzer of claim 4, where the characteristic data comprises a frequency value of magnetic permeable masses that have passed the fixed position.

10. The traffic analyzer of claim 4, further comprising a wireless transmitter operative to wirelessly transmit the characteristic data output by the programmable processor.

11. A traffic analyzer for detecting a magnetic permeable mass passing a fixed position, the traffic analyzer comprising:

a calibrated magnetic background memory device calibrated with a threshold value;

a first magnetic field detector operative to detect a first change in a first magnetic field, the first change being caused by a magnetic permeable mass, and further operative to generate a first analog output indicative of the first change in the magnetic field;

a window comparator operative to generate a comparative output where the first analog output exceeds the magnetic background value;

a second magnetic field detector operative to detect a second change in the magnetic field, the second change caused by the magnetic permeable mass, and further operative to generate a second analog output indicative of the second change in the magnetic field;

a first analog-to-digital converter operative to generate a first digital output by sampling the first analog output;

a second analog-to-digital converter operative to generate a second digital output by sampling the second analog output; and

,

a programmable processor operative to generate characteristic data indicative of the magnetic permeable mass based on the first digital output and the second digital output, the programmable processor being activated based on the comparative output.

12. The traffic analyzer of claim 11, where the programmable processor is further operative to determine whether the magnetic permeable mass is a vehicle based on comparing the time of the detected first change with the time of the detected second change.

13. The traffic analyzer of claim 11, further comprising:

a first signal conditioning off-amplifier operative to amplify the first analog output;

a second signal conditioning off-amplifier operative to amplify the second analog output;

a first bandpass filter operative to filter the first amplified analog output based on a predetermined frequency, the first filtered amplified analog output being used to generate the first digital output; and

,

a second bandpass filter operative to filter the second amplified analog output based on a predetermined frequency, the second filtered amplified analog output being used to generate the second digital output.

14. The traffic analyzer of claim 11, further comprising a real-time clock operative to calculate a time value based on a pre-determined interval, where the programmable processor is further operative to associate the characteristic data with the calculated time value.

15. The traffic analyzer of claim 11, further comprising memory operative to store the characteristic data output by the programmable processor.

16. The traffic analyzer of claim 15, where the characteristic data is stored in the memory using a dynamic distribution classification.

17. The traffic analyzer of claim 15, where the memory is flash memory.

18. The traffic analyzer of claim 11, where the characteristic data comprises a frequency value of magnetic permeable masses that have passed the fixed position.

19. The traffic analyzer of claim 11, where the characteristic data comprises a speed value of the magnetic permeable mass.

20. The traffic analyzer of claim 11, further comprising a wireless transmitter operative to wirelessly transmit the characteristic data.

21. A method for detecting a magnetic permeable mass passing a fixed position, the method comprising:

determining a threshold value;

detecting a change in a magnetic field in response to a magnetic permeable mass passing a fixed position;

generating an analog output indicative of the detected change in the magnetic field;

comparing the analog output with the threshold value;

generating a comparative output where the analog output value exceeds the threshold value;

generating a digital output by sampling the analog output; and

,

activating a programmable processor to output characteristic data based on the digital output, the programmable processor being activated based on the comparative output.

22. The method of claim 21, further comprising:

amplifying the analog output; and

,

filtering the amplified analog output based on a predetermined frequency, the filtered amplified analog output being used to generate the digital output value.

24. The method of claim 21 further comprising storing the characteristic data in memory.

25. The method of claim 24, where the memory is flash memory.

26. The method of claim 21, where the characteristic data comprises a frequency value of magnetic permeable masses that have passed the fixed position.

27. The method of claim 21, further comprising wirelessly transmitting the characteristic data.

23. The method of method 21, further comprising:

calculating a time value based on a pre-determined interval; and

,

associating the characteristic data with the calculated time value.

28. A method for detecting a magnetic permeable mass passing a fixed position, the method comprising:

determining a threshold value;

detecting a first change in a magnetic field in response to a magnetic permeable mass passing a fixed position;

generating a first analog output indicative of the detected first change in the magnetic field;

comparing the first analog output with the threshold value;

generating a comparative output where the first analog output exceeds the threshold value;

detecting a second change in the magnetic field in response to the magnetic permeable mass passing the fixed position;

generating a second analog output indicative of the detected second change in the second magnetic field;

generating a first digital output by sampling the first analog output;

generating a second digital output by sampling the second analog output; and

,

activating a programmable processor to calculate characteristic data of the magnetic permeable mass based on the first digital output and the second digital output, the programmable processor being activated based on the comparative output.

29. The method of claim 28, further comprising determining whether the magnetic permeable mass is a vehicle based on calculating the time between the detected first change the time of the detected second change;

and comparing the calculated time between the detected first change and the detected second change with a predetermined time value.

30. The method of claim 28, wherein the characteristic data of the magnetic permeable mass is calculated by correlating the first digital output with the second digital output.

31. The method of claim 30, wherein correlating the first digital output with the second digital output comprises using the programmable processor to calculate at least one point of a magnitude plot, wherein the at least one point is calculated by computing the absolute value of the summation of the first digital output and the second digital output.

32. The method of claim 30, wherein the correlating the first digital output value with the second digital output comprises using the programming processor to calculate at least one point of a magnitude plot, wherein the at least one point is calculated by computing the absolute value of the difference between the first digital output and the second digital output.

33. The method of claim 28 further comprising:

amplifying the first analog output;

amplifying the second analog output;

filtering the first amplified analog output based on a predetermined frequency, the first filtered amplified analog output being used to generate the first digital output; and

,

filtering the second amplified analog output based on a predetermined frequency, the second filtered amplified analog output being used to generate the second digital output.

34. The method of claim 28 further comprising:

calculating a time value based on a pre-determined interval; and

,

associating the characteristic data with the calculated time value.

35. The method of claim 28 further comprising storing the characteristic data in memory.

36. The method of claim 35, where the characteristic data is stored in the memory using a dynamic distribution classification.

37. The method of claim 35, where the memory is flash memory.

38. The method of claim 28, where the characteristic data comprises a frequency value of magnetic permeable masses that have passed the fixed position.

39. The method of claim 28, where the characteristic data comprises a speed value of the magnetic permeable mass.

40. The method of claim 28, further comprising wirelessly transmitting the characteristic data.

41. A method for reinitializing a traffic analyzer after a failure, the method comprising:

associating an incremental value with a predetermined time interval;

detecting a change in a magnetic field in response to a magnetic permeable mass passing a fixed position;

generating a detected output indicative of the detected change in the magnetic field;

generating a comparative output where the detected output exceeds a threshold value;

activating a programmable processor to store characteristic data in a memory storage device based on the detected output, the programmable processor being activated based on the comparative output;

storing the characteristic data in the memory storage device where the characteristic data is associated with the incremental value;

reading the characteristic data from the memory storage device after a failure to determine the incremental value associated with the characteristic data;

maintaining an incremental count based on determining the incremental value associated with the characteristic data; and

,

updating a real-time clock based on the incremental count.