Sensor and method of detecting the condition of a turf grass

• US 20050024213A1
• Filed: 09/05/2003
• Published: 02/03/2005
• Est. Priority Date: 08/01/2003
• Status: Active Grant

• Current Assignee: Li & S Company Limited (Yesco Holdings Co., Ltd.)
• Original Assignee: Li & S Company Limited (Yesco Holdings Co., Ltd.)
• Inventors: Ediger, Kevin, Franzen, David, Demetriades-Shah, Tanvir, Welles, Jonathan M., Biggs, Greg, Rada, John
• Granted Patent: US 7,362,439 B2
• Time in Patent Office: Days
• US Class Current: 340/600
• CPC Class Codes: A01D 34/006 Control or measuring arrangements
• CPC Class Codes: G01N 21/55 Specular reflectivity

Abstract

A method of detecting the condition of a turf grass is described. According to one aspect of the invention, the method comprises steps of attaching an active sensor to a mower; traversing a section of turf grass; and processing the output of the sensor. A device for detecting the condition of turf grass is also disclosed. The device comprises an array of illuminating devices generating a pattern of illuminating light; a detecting device receiving a pattern of reflected light which is coincident with the pattern of illuminating light; a detecting device adapted to detect stray light from the array of illuminating devices; and a feedback loop controlling the array of illuminating devices. A system employing the device is also disclosed.

Claims

1. A method of detecting the foliage density of a turf grass, said method comprising the steps of:

attaching an active sensor to a mower;

traversing a section of turf grass;

providing an illuminating pattern of light to said turf grass;

receiving a reflected pattern of light which is coincident with said illuminating pattern of light; and

processing an output of said active sensor.

2. The method of claim 1 wherein said step of attaching an active sensor to a mower comprises attaching an active sensor to a back of said mower.

3. The method of claim 2 further comprising a step of attaching a second sensor to a front of said mower.

4. The method of claim 1 wherein said step of processing an output of said active sensor comprises a step of processing an output of said active sensor at said mower.

5. The method of claim 1 wherein said step of processing an output of said active sensor comprises providing data output by said active sensor to a remote location.

6. The method of claim 5 wherein said step of providing data output by said active sensor to a remote location comprises transmitting said data output by said active sensor to a base station by way of a wireless connection.

7. The method of claim 1 wherein said step of providing data output by said active sensor to a base station by way of a wireless connection comprises transmitting said data when said mower is off.

8. The method of claim 1 further comprising a step of aligning sensor data with position data.

9. The method of claim 1 further comprising a step of providing a report of said condition of said turf grass.

10. The method of claim 1 further comprising a step of automatically detecting an active sensor type.

11. The method of claim 1 further comprising a step of detecting when said mower is mowing said turf grass using an electrical signal provided by said mower which is in one electrical state when the reels of said mower are in a mowing position and are mowing and is in a different electrical state when the reels of said mower are not in the mowing position or are not mowing.

12. The method of claim 1 further comprising a step of calibrating said active sensor.

13. The method of claim 1 further comprising a step of using a laser pointer for alignment.

14. The method of claim 1 further comprising a step of detecting anomalies in said turf grass.

15. A method of detecting a condition of a turf grass, said method comprising the steps of:

attaching an active sensor to a mower;

providing an illuminating pattern of light to said turf grass; and

receiving a reflected pattern of light which is coincident with said illuminating pattern of light.

16. The method of claim 15 further comprising a step of providing constant LED output control.

17. The method of claim 16 wherein said step of providing constant LED output control comprises sensing stray illumination light by way of feedback photodiodes.

18. The method of claim 15 wherein said step of providing an illuminating pattern of light comprises providing active illumination of at least two narrow band wavelengths.

19. The method of claim 15 further comprising a step of providing an aperture protruding through an illumination window.

20. The method of claim 15 wherein said step of providing an illuminating pattern of light to said turf grass comprises providing an illuminating cone of light to said turf grass.

21. A method of detecting a condition of a turf grass, said method comprising the steps of:

attaching an active sensor to a mower;

providing a first wavelength of light and a second wavelength of light to simultaneously illuminate an area; and

detecting both reflected light signals simultaneously.

22. The method of claim 21 further comprising the steps of:

modulating said first wavelength of light and said second wavelength of light at independent frequencies; and

demodulating said reflected light signals at a correct corresponding frequency.

23. The method of claim 21 further comprising the steps of:

attaching a plurality of sensors to a mower; and

positioning said plurality of sensors such that there is optical overlap from illumination of one sensor to a received field-of-view of an adjacent sensor.

24. A method of detecting a condition of a turf grass, said method comprising the steps of:

providing a plurality of illumination devices;

coupling a feedback circuit to adjust an output of each illuminating device of said plurality of illuminating devices;

detecting an irradiance of each illuminating device of said plurality of illuminating devices; and

adjusting the irradiance of an illuminating device of said plurality of illuminating devices.

25. The method of claim 24 wherein said step of providing a plurality of illumination devices comprises providing a plurality of illumination devices in concentric circles.

26. The method of claim 25 wherein said step of adjusting an irradiance of an illuminating device of said plurality of illuminating devices comprises adjusting illumination devices based upon said concentric circles.

27. The method of claim 25 further comprising a step of providing different frequencies per concentric circles.

28. A method of detecting the a condition of a turf grass, said method comprising the steps of:

attaching an active sensor to a mower, wherein the active sensor is free of collection optics;

sensing a condition of said turf grass; and

detecting a geographic position of said active sensor while sensing the condition of said turf grass.

29. The method of claim 28 wherein said step of sensing a condition of said turf grass comprises using a pulse-per-second output from a positioning determining unit.

30. The method of claim 28 wherein said step of sensing a condition of said turf grass comprises oversampling sensed data of the condition of said turf grass.

31. The method of claim 30 further comprising a step of aligning the sensed data with position data.

32. The method of claim 30 further comprising a step of processing said data and converting said data to a map.

33. A device for detecting a condition of turf grass, said device comprising:

an array of illuminating devices generating a pattern of illuminating light;

a detecting device receiving a pattern of reflected light which is coincident with said pattern of illuminating light;

a detecting device adapted to detect an entity proportional to a light output from said array of illuminating devices; and

a feedback loop controlling said array of illuminating devices.

34. The device of claim 33 wherein said array of illuminating devices comprises LEDs having a plurality of modulation frequencies.

35. The device of claim 33 wherein said feedback loop comprises a first demodulator for a first frequency and a second demodulator for a second frequency.

36. The device of claim 33 wherein said detecting device detects stray light from said array of illuminating devices.

45. The device of claim 33 wherein said feedback loop comprises more than one demodulator for more than one frequency.

37. A device for detecting a condition of turf grass, said device comprising:

an array of LEDs generating a cone of illuminating light;

a photodetector receiving a cone of reflected light which is coincident with said cone of illuminating light;

one or more photodetectors adapted to detect light from said array of LEDs; and

a feedback loop controlling said array of LEDs based upon light from said array of LEDs.

38. The device of claim 37 wherein said array of LEDs comprises LEDs having a plurality of modulation frequencies.

39. The device of claim 37 wherein said feedback loop comprises a first demodulator for a first frequency and a second demodulator for a second frequency.

40. The device of claim 37 further comprising a circuit for providing offset correction.

41. The device of claim 40 wherein said circuit for providing offset correction comprises a first offset correction circuit for a first frequency and a second offset correction circuit for a second frequency.

42. The device of claim 37 further comprising a background light subtraction circuit.

43. The device of claim 37 wherein said detecting device detects stray light from said array of illuminating devices.

44. A device for detecting a condition of turf grass, said device comprising:

an array of LEDs generating a pattern of illuminating light;

at least one photodetector receiving a pattern of reflected light which is coincident with said pattern of illuminating light;

one or more photodetectors adapted to detect stray light from said array of LEDs;

a feedback loop controlling said array of LEDs based upon stray light from said array of LEDs;

a circuit for providing offset correction, said circuit comprising a first offset correction circuit for a first frequency and a second offset correction circuit for a second frequency; and

a background light subtraction circuit.

46. A method of detecting a condition of a turf grass, said method comprising the steps of:

attaching an active sensor to a mower;

providing more than two wavelengths of light to illuminate an area; and

detecting reflected light signals.

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

modulating one or more wavelengths of said light at independent frequencies; and

demodulating said reflected light signals at a correct corresponding frequency.

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

attaching a plurality of sensors to a mower; and

positioning said plurality of sensors such that there is optical overlap from illumination of one sensor to a received field-of-view of an adjacent sensor.

49. A method of detecting a condition of a turf grass, the method comprising:

attaching an active sensor to a mower;

traversing a section of turf grass; and

processing an output of the active sensor;

wherein the active sensor comprises a window with anti-fog coating.

50. A method of detecting a condition of a turf grass, the method comprising:

attaching an active sensor to a mower;

traversing a section of turf grass; and

processing an output of the active sensor;

wherein the active sensor comprises a window with a heating mechanism.

51. A method of detecting a condition of a turf grass, the method comprising:

attaching an active sensor to a mower;

traversing a section of turf grass; and

processing an output of the active sensor;

wherein the active sensor comprises;

a window;

an anti-fog heater; and

a heater driver controlling the anti-fog heater.

52. A method of detecting a condition of a turf grass, the method comprising:

attaching an active sensor to a mower;

traversing a section of turf grass; and

processing an output of the active sensor;

wherein the active sensor is free of collection optics, whereby the active sensor is insensitive to depth-of-field and height variations.