Wireless optical instrument for position measurement and method of use therefor

• US 6,608,688 B1
• Filed: 05/16/2001
• Issued: 08/19/2003
• Est. Priority Date: 04/03/1998
• Status: Expired due to Term

• Current Assignee: Image Guided Technologies, Inc. (Stryker Corporation)
• Original Assignee: Image Guided Technologies, Inc. (Stryker Corporation)
• Inventors: Pasquini, Ronald M., Skelton, Brett R., Faul, Ivan, Schulz, Waldean A.
• Primary Examiner(s): STAFIRA, MICHAEL PATRICK
• Application Number:
  US09/647,365
• Time in Patent Office: 825 Days
• Field of Search: 356/614, 356/3, 250/221, 345/158, 345/175, 345/176, 345/179, 345/180, 345/182, 345/166
• US Class Current: 356/614
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: G06F 3/0325 using a plurality of light emitters or reflectors or a plurality of detectors forming a reference frame from which to derive the orientation of the object, e.g. by triangulation or on the basis of reference deformation in the picked up image
• CPC Class Codes: G06F 3/0346 with detection of the device orientation or free movement in a 3D space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors
• CPC Class Codes: G06F 3/03545 Pens or stylus

Abstract

Disclosed is a wireless instrument tracking system. The wireless instrument tracking system is used for determining the location of at least one point relative to the instrument in a three-dimensional space relative to a three-dimensional coordinate tracking system. Advantageously, a first wireless instrument can be placed into the optical field with the wireless instrument including a wireless receiver and at least one optical position indicator. The optical position indicator is typically light emitting diodes (18) and communicates with corresponding measurement sensors (30) across a wireless optical link. The wireless optical link is time multiplexed with repetitive time frames divided into time slots. Each LED (18) emits an infrared signal or flashes in a respective time slot of a time frame. The measurement sensors (30) are preferably CCD cameras. The LEDs (18) are synchronized with the cameras and once synchronized each LED (18) flashes in a different time slot in synchronization with the camera frame rate.

Claims

1. A tracking system for tracking the location of an object in three dimensional space, the system comprising:

the object having a wireless receiver and first and second optical position indicators;

controlling apparatus in communication with the receiver and operable therewith to direct the indicators to provide signals; and

a detector capable of detecting the signals so that the system can determine the location of the object.

2. The system of claim 1, wherein the receiver is a transceiver.

3. The system of claim 1, wherein the optical position indicators emit electromagnetic radiation.

4. The system of claim 3, wherein the optical position indicators are LED'"'"'s.

5. The system of claim 1, wherein the optical position indicators are reflective markers.

6. The system of claim 4, further comprising a converter.

7. The system of claim 3, further comprising modulation sensors for sensing a modulated optical signal emitted from each of the optical position indicators.

8. The system of claim 7, wherein the modulation sensor comprises a photodiode.

9. The system of claim 1, wherein the detector includes first and second CCD cameras.

10. The system of claim 9, further comprising a third optical position indicator, non-collinear with the other optical position indicators, wherein the indicators enable determination of pitch, roll, and yaw data of the object.

11. The system of claim 1, wherein the controlling apparatus includes a transmitter.

12. The system of claim 1, wherein the object includes a memory.

13. The system of claim 12, further comprising means for transferring information from said memory to said controller.

14. The system of claim 1, wherein communication between the controlling apparatus and the receiver is through one of an infrared link, a radio frequency link, or an ultrasound link.

15. The system of claim 1, wherein communication between the detector and the signals comprises an optical link divided into repetitive time frames, each time frame divided into repetitive time slots.

16. The system of claim 15, wherein the object comprises a first object and the wireless receiver comprises a first wireless receiver, the system further comprising a second object having both a second wireless receiver and two optical position indicators.

17. The system of claim 16, wherein the first object is assigned a particular time slot in each time frame and the second object is assigned a particular different time slot in each time frame.

18. The system of claim 12, wherein the duration of each time frame is dependent on the number of optical position indicators mounted on each object.

19. The system of claim 1, wherein the signals and the controlling apparatus are time multiplexed.

20. The system of claim 19, wherein the receiver and the controller each further comprise a low drift clock allowing the receiver and controller to maintain prolonged synchronization with respect to each other.

21. The system of claim 19, wherein the receiver and the controller are synchronized from an external source.

22. The system of claim 21, wherein the external source is a time signal received from one of a satellite, a radio frequency time beacon, or radiation of surrounding electrical apparatus.

23. The system of claim 1, wherein the object is one of a probe, a reference frame, a removable pod, or a single LED.

24. The system of claim 1, further comprising an optical filter.

25. The system of claim 24, wherein the optical filter comprises a combination of short and long pass optical filters.

26. The system of claim 1, further comprising a filter circuit.

27. The system of claim 26, further comprising an amplifier.

28. The system of claim 27, further comprising a discrimination circuit.

29. The system of claim 1, further comprising a button disposed on the object for transmitting state information.

30. The system of claim 1, further comprising a wired instrument connected to the controlling and processing apparatus by a wired path.

31. A tracking system for tracking the location of an object in three dimensional space, the system comprising:

the object having first and second optical position indicators that fire signals autonomously in a timed pattern;

a detector capable of detecting the pattern; and

controlling apparatus capable of learning the pattern and synchronizing measurements with the timed pattern.

32. The system of claim 31, wherein the optical position indicators emit electromagnetic radiation.

33. The system of claim 32, wherein the optical position indicators are LED'"'"'s.

34. The system of claim 33, wherein the detector includes first and second CCD cameras.

35. The system of claim 34, further comprising a third optical position indicator, non-collinear with the other optical position indicators, wherein the indicators enable determination of pitch, roll, and yaw data of the object.

36. The system of claim 35, wherein the object includes a memory.

37. The system of claim 36, wherein communication between the detector and the signals comprises an optical link divided into repetitive time frames, each time frame divided into repetitive time slots.

38. The system of claim 37, wherein the object is a first object assigned a particular time slot in each time frame, the system further comprising a second object capable of being assigned a particular different time slot in each time frame.

39. A tracking system for tracking the location of a plurality of objects in three dimensional space, the system comprising:

each of the objects having a wireless receiver and first and second optical position indicators that provide a position signal for each object;

controlling apparatus that transmits synchronization pulses to cause each of the objects to provide a position signal at a designated time slot; and

a detector capable of detecting the signals so that the system can determine the location of each of the objects.

40. The system of claim 39, wherein the receiver is a transceiver.

41. The system of claim 39, wherein the optical position indicators are LED'"'"'s.

42. The system of claim 41, wherein the receiver and the controller each further comprise a low drift clock allowing the receiver and controller to maintain prolonged synchronization with respect to each other.

43. The system of claim 41, wherein the receiver and the controller are synchronized from an external source.

44. The system of claim 41, further comprising a third optical position indicator, non-collinear with the other optical position indicators, wherein the indicators enable determination of pitch, roll, and yaw data of the object.

45. A tracking system for tracking the location of a plurality of objects in three dimensional space, the system comprising:

each of the objects having a wireless transceiver and first and second optical position indicators that provide a position signal for each object;

a detector capable of detecting the signals so that the system can determine the location of the object; and

controlling apparatus incorporating a search channel time slot and a plurality of other time slots wherein the controlling apparatus is capable of recognizing objects during the search slot and wherein the controlling apparatus is also capable of assigning each of the objects to one of the other time slots.

46. The system of claim 45, wherein the optical position indicators are LED'"'"'s.

47. The system of claim 45, further comprising a third optical position indicator, non-collinear with the other optical position indicators, wherein the indicators enable determination of pitch, roll, and yaw data of the object.

48. The system of claim 47, wherein the objects each include a memory.

49. The system of claim 48, further comprising means for transferring information from each memory to the controller.

50. A method of tracking the location of an object in three dimensional space, the method comprising the steps of:

providing the object a wireless receiver and disposing first and second optical position indicators in fixed relation to the object;

controlling the indicators to provide signals through communication with the receiver; and

detecting the signals with a detector so that the system can determine the location of the object.

51. The method of claim 50, wherein the receiver is a transceiver.

52. The method of claim 50, further comprising the step of transferring data from the object to controlling apparatus.

53. The method of claim 52, wherein the data is one of a serial number for the object, calibration data of the object, or identification data of the object.

54. The method of claim 50, wherein the optical position indicators are LED'"'"'s.

55. The method of claim 50, further comprising the step of disposing a third optical position indicator on the object, non-collinear with the other optical position indicators, wherein the indicators enable determination of pitch, roll, and yaw data of the object.

56. The method of claim 50, wherein the object includes a memory.

57. The method of claim 50, wherein controlling the indicators is accomplished by one of an infrared link between controlling apparatus and the object, a radio frequency link between controlling apparatus and the object, or an ultrasound link between controlling apparatus and the object.

58. The method of claim 50, wherein detection of the signals includes establishing an optical link divided into repetitive time frames, each time frame divided into repetitive time slots.

59. The method of claim 58, further comprising the step of providing a plurality of objects each having both a receiver and optical position indicators wherein each of the objects is assigned a particular time slot.

60. The method of claim 59, wherein the optical position indicators of each object emit electromagnetic radiation during the time slot assigned to each respective object.

61. The method of claim 59, wherein one of the repetitive time slots is used as a shared time slot to arbitrate assignment of the objects.

62. The method of claim 61, wherein an ALOHA scheme is used to arbitrate data collisions from multiple objects.

63. The method of claim 50, wherein the object comprises a first object and the wireless receiver comprises a first wireless receiver, the method further comprising the step of providing a second object having both a second wireless receiver and two optical position indicators.

64. The method of claim 50, further comprising the step of providing each of the receiver and the controller a low drift clock allowing the receiver and controller to maintain prolonged synchronization with respect to each other.

65. The method of claim 50, further comprising the step of synchronizing the receiver and the controller with an external source.

66. The method of claim 50, further comprising the step of modulating the signals.

67. The method of claim 50, wherein the object comprises a first object and the receiver comprises a first receiver, the method further comprising the step of providing a second object having a second receiver wherein the second receiver is wired to controlling apparatus.

68. The method of claim 50, further comprising the step of anticipating when the optical position indicators transmit data.

69. The method of claim 68, further comprising the step of recording a sequence of repetitive transmissions of synchronization signals from controlling apparatus and analyzing the sequence to determine the length and pattern of data transmission.

70. The method of claim 50, wherein the controlling step is performed by controlling apparatus that transmits a control signal to the object before the next transmission from the object.

71. The method of claim 50, wherein the detector is in synchronization with the optical position indicators.

72. A method of tracking the location of an object in three dimensional space, the method comprising the steps of:

providing the object with first and second optical position indicators in fixed relation thereto wherein the indicators fire autonomously in a timed pattern;

detecting the signals with a detector; and

providing controlling apparatus that learns the pattern and synchronizes measurements with the timed pattern.

73. The method of claim 72, further comprising the step of providing the object a third optical position indicator, non-collinear with the other optical position indicator, wherein the indicators enable determination of pitch, roll, and yaw data of the object.

74. The method of claim 73, wherein communication between the detector and the signals comprises an optical link divided into repetitive time frames, each time frame divided into repetitive time slots.

75. The method of claim 74, wherein the object is a first object assigned a particular time slot in each time frame, the method further comprising the step of providing a second object and assigning thereto a particular different time slot in each time frame.

76. A method of tracking the location of a plurality of objects in three dimensional space, the method comprising the steps of:

providing each of the objects a wireless receiver and first and second optical position indicators that provide a position signal for each object;

transmitting synchronization pulses from controlling apparatus to cause each of the objects to provide a position signal at a designated time slot; and

detecting the signals with a detector so that the system can determine the location of the object.

77. The method of claim 76, wherein the receiver is a transceiver.

78. The method of claim 76, further comprising the step of providing each of the receivers and the controller a low drift clock allowing the receiver and controller to maintain prolonged synchronization with respect to each other.

79. The method of claim 76, further comprising the step of synchronizing the receivers and controller with external source.

80. The method of claim 76, further comprising the step of providing each of the objects with a third optical position indicator, non-collinear with the other optical position indicators, wherein the indicators enable determination of pitch, roll, and yaw data of the object.

81. A method of tracking the location of a plurality of objects in three dimensional space, the method comprising the steps of:

providing each of the objects a wireless transceiver and first and second optical position indicators that provide a position signal for each object;

providing controlling apparatus having a search channel time slot and a plurality of other time slots;

providing a detector having an optical field;

recognizing one or more objects during the search channel time slot;

assigning each of the one or more objects to one of the other time slots; and

detecting signals from the one or more of the objects so that the system can determine the location of the one or more objects.

82. The method of claim 81, further comprising the step of providing each of the objects a third optical position indicator, non-collinear with the other optical position indicators, wherein the indicators enable determination of pitch, roll, and yaw data of the by object.

83. The method of claim 81, wherein each object is recognized during the search channel time slot upon entering the optical field.