System and tracker for tracking an object, and related methods

• US 7,289,227 B2
• Filed: 10/01/2004
• Issued: 10/30/2007
• Est. Priority Date: 10/01/2004
• Status: Active Grant

• Current Assignee: Best Medical International Incorporated (TeamBest Group)
• Original Assignee: Nomos Corporation (North American Scientific, Inc.)
• Inventors: Smetak, Edward Charles, Scherch, John David
• Primary Examiner(s): Nguyen; Tu T.
• Application Number:
  US10/957,128
• Publication Number:
  US 20060072124A1
• Time in Patent Office: 1,124 Days
• Field of Search: None
• US Class Current: 356/614
• CPC Class Codes: A61B 2017/0046 with a releasable handle; with handle and operating part separable for prosthetic joint-implanting tools A61F2/4603
• CPC Class Codes: A61B 2017/00477 Coupling A61B2017/0046 takes precedence
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 2090/3937 Visible markers
• CPC Class Codes: A61B 2090/3983 Reference marker arrangements for use with image guided surgery
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/064 using markers A61B5/062 takes precedence
• CPC Class Codes: A61B 8/4245 involving determining the position of the probe, e.g. with respect to an external reference frame or to the patient
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: G01S 17/875 for determining attitude

Abstract

A system to track a three-dimensional position and an orientation of a movable object and associated methods are provided. The system includes a tracker having an optically trackable body adapted to connect to the movable object. A plurality of optical indicators are connected or mounted to the optically trackable body to form a plurality of geometric figures. A plurality of obfuscating flanges optically separate the optical indicators from each other to prevent each of the optical indicators from becoming optically coincident with another optical indicator when viewed along a preselected viewing path. The system also includes an apparatus to track the tracker having an optical detector to simultaneously detect the three-dimensional position of at least three of the plurality of optical indicators and a determiner to determine the three-dimensional position and orientation of the optically trackable body from the position of the optical indicators.

Claims

1. A system for tracking a three-dimensional position and an orientation of a movable object, the system comprising:

a tracker comprising;

a plurality of separate and spaced apart optical retro-reflective spheres having a preselected segment length between each pair combination of the plurality of optical retro-reflective spheres, a plurality of combinations of at least three of the plurality of optical retro-reflective spheres defining a plurality of geometric figures, each of the plurality of retro-reflective spheres adapted to be optically tracked over a subset of possible movable object orientations to provide three-dimensional positional data and orientation data of the movable object, and

an optically trackable body having the plurality of optical retro-reflective spheres mounted thereto and having a proximal body end portion, a distal body end portion, a medial body portion connected to and extending between the proximal body end portion and the distal body end portion, a longitudinal axis, and separating means for optically separating each of the plurality of optical retro-reflective spheres from each other to prevent each of the plurality of retro-reflective spheres from becoming optically coincident with another one of the plurality of retro-reflective spheres when viewed along a collinear viewing path extending directly through either adjacent pair of the plurality of retro-reflective spheres to enhance optical detection of the plurality of retro-reflective spheres to thereby enhance determination of the positional location and orientation of the movable object; and

an apparatus to track a trackable body, the apparatus comprising;

an optical detector having an optical detector body adapted to be positioned separate and spaced apart from the optically trackable body at a three-dimensional optical detector reference location, and including a pair of separate and spaced apart optical receivers connected to the optical detector body, each having a field of view and being adapted to receive optical energy reflected by each of the plurality of optical retro-reflective spheres when positioned in the field of view to thereby detect the three-dimensional sphere position of each of the plurality of retro-reflective spheres when positioned simultaneously within the field of view of both of the optical receivers to produce a plurality of position signals representing such three-dimensional sphere positions, and a pair of infrared illuminators, a first illuminator positioned adjacent one of the pair of separate and spaced apart optical receivers and a second illuminator positioned adjacent the other of the pair of separate and spaced apart optical receivers to selectively illuminate each of the plurality of optical retro-reflective spheres when positioned in the field of view of the respective adjacent optical receiver to thereby energize the optical retro-reflective spheres within the field of view of the respective adjacent optical receiver, and

a determiner in communication with the optical detector and responsive to the plurality of position signals produced by the optical detector to determine the three-dimensional sphere position of each of the plurality of retro-reflective spheres when positioned simultaneously within the field of view of both of the optical receivers of the optical detector and having a memory associated therewith to store a table of definitions containing the segment lengths between each of the plurality of optical retro-reflective spheres to determine, responsive to the segment lengths, which of the plurality of geometric figures is in view of the optical receivers, when so positioned, to thereby determine the three-dimensional position and the orientation of the movable object.

2. A system as defined in claim 1, wherein the separating means includes a plurality of medial body portion obfuscating flanges sized and positioned substantially parallel to and spaced apart from the longitudinal axis of the medial body portion of the optically trackable body to optically separate each sphere of the plurality of optical retro-reflective spheres mounted to the medial body portion of the optically trackable body from each adjacent sphere of the plurality of optical retro-reflective spheres also mounted to the medial body portion of the optically trackable body to prevent each sphere of the plurality of retro-reflective spheres mounted to the medial body portion of the optically trackable body from becoming optically coincident with each adjacent sphere of the plurality of optical retro-reflective spheres also mounted to the medial body portion of the optically trackable body, when viewed along the collinear viewing path of either of the pair of optical receivers.

3. A system as defined in claim 1, wherein the separating means includes a medial body portion obfuscating flange positioned substantially axially parallel with the longitudinal axis of the medial body portion of the optically trackable body and positioned and sized to optically separate each sphere of the plurality of optical retro-reflective spheres mounted to the distal body end portion of the optically trackable body from each sphere of the plurality of optical retro-reflective spheres mounted to the medial body portion of the optically trackable body to prevent each sphere of the plurality of retro-reflective spheres mounted to the distal body portion of the optically trackable body from becoming optically coincident with each other sphere of the plurality of optical retro-reflective spheres mounted to the medial body portion of the optically trackable body, when viewed along the collinear viewing path of either of the pair of optical receivers.

4. A system as defined in claim 1, wherein the distal body end portion of the optically trackable body has a pair of adjacent optical retro-reflective spheres mounted thereto, and wherein the separating means includes a distal body end portion obfuscating flange positioned substantially axially perpendicular to the longitudinal axis of the medial body portion of the optically trackable body and positioned and sized to optically separate a first sphere of the pair of optical retro-reflective spheres mounted to the distal body end portion of the optically trackable body from a second sphere of the pair of optical retro-reflective spheres mounted to the distal body portion of the optically trackable body to prevent the first sphere of the pair of adjacent optical retro-reflective spheres mounted to the distal body end portion of the optically trackable body from becoming optically coincident with the second sphere of the pair of optical retro-reflective spheres mounted to the distal body end portion of the optically trackable body, when viewed along the collinear viewing path of either of the pair of optical receivers.

5. A system as defined in claim 1, wherein each sphere in the plurality of optical retro-reflective spheres is positioned to form at least two of the plurality of geometric figures to reduce a selected number of spheres required to determine the positional location and orientation of the movable object to thereby reduce overall size and complexity of the optically trackable body.

6. A system as defined in claim 1, further comprising a mounting connector adapted to connect the optically trackable body to the movable object, and wherein the optically trackable body further includes an interior mount recess inwardly extending from the proximal body end portion into the medial body portion and adapted to slidably receive at least portions of the mounting connector.

7. A system as defined in claim 6, wherein the mounting connector includes an annular mounting connector recess adapted to receive the mounting connector within the interior mount recess when so inserted, and wherein the medial body portion of the optically trackable body further includes a mounting connector retention recess extending between outer surface portions of the medial body portion and inner surface portions of the interior mount recess and positioned substantially normal to the interior mount recess to house at least portions of a mounting connector retention lock member.

8. A system as defined in claim 6, wherein the medial body portion of the optically trackable body further includes a mounting connector retention recess extending between outer surface portions of the medial body portion and inner surface portions of the interior mount recess and positioned substantially normal to the interior mount recess, and a collapsible mounting connector retention lock member housed at least partially within the mounting connector retention recess and adapted to extend through inner surface portions of the interior mount recess when the mounting connector is substantially extended inward within the interior mount recess defining at least a partially-collapsed and inwardly biased lock position, adapted to collapse outward responsive to an outward pressure from the mounting connector when the mounting connector is partially retracted outward from within the interior mount recess defining a collapsed and an unlocked position, and adapted to extend inward through the inner surface portions of the interior mount recess when the mounting connector is substantially retracted outward from within the interior mount recess defining a non-collapsed and inwardly biased unlocked position.

9. A system as defined in claim 1, wherein the proximal body end portion of the optically trackable body further includes a proximal body end mounting extension connected to and integral with the proximal body end portion of the body, extending substantially perpendicular to and outwardly from the longitudinal axis of the optically trackable body, and having a substantially flat planer proximal surface adapted to interface with a surface of at least one of the movable object and a movable object mount.

10. A system as defined in claim 9, wherein the proximal body end mounting extension includes at least one longitudinal recess parallel to and spaced radially apart from the longitudinal axis of the optically trackable body and adapted to receive at least portions of at least one of the movable object mount and a mount alignment key and adapted to angularly compel the proximal body end mounting extension of the optically trackable body in a predetermined position with respect to at least one of the movable object and the movable object mount to thereby prevent the optically trackable body from being mounted to the at least one of the movable object and the movable object mount in an incorrect orientation.

11. A tracker comprising:

a plurality of separate and spaced apart indicators having a preselected segment length between each pair combination of the plurality of indicators, a plurality of combinations of at least three of the plurality of indicators to form a plurality of geometric figures, each of the plurality of indicators adapted to be optically tracked over a subset of possible movable object orientations to provide three-dimensional positional data and orientation data of the movable object; and

an optically trackable body having the plurality of indicators mounted thereto and having a proximal body end portion, a distal body end portion, a medial body portion connected to and extending between the proximal body end portion and the distal body end portion, a longitudinal axis, and a plurality of obfuscating flanges sized and positioned to optically separate each of the plurality of indicators from each other to prevent each of the plurality of indicators from becoming optically coincident with another one of the plurality of indicators when viewed along a plurality of viewing paths extending directly through each pair combination of the plurality of indicators to enhance optical detection of the plurality of indicators.

12. A tracker as defined in claim 11, wherein the plurality of obfuscating flanges includes a plurality of medial body portion obfuscating flanges sized and positioned substantially parallel to extending outwardly from the longitudinal axis of the medial body portion of the optically trackable body to optically separate each indicator of the plurality of indicators mounted to the medial body portion of the optically trackable body from each adjacent indicator of the plurality of indicators also mounted to the medial body portion of the optically trackable body to prevent each indicator of the plurality of indicators mounted to the medial body portion of the optically trackable body from becoming optically coincident with each adjacent indicator of the plurality of indicators also mounted to the medial body portion of the optically trackable body, when viewed along either of the plurality of viewing paths extending directly through each adjacent pair of the plurality of indicators mounted to the medial body portion of the optically trackable body.

13. A tracker as defined in claim 11, wherein the plurality of obfuscating flanges includes a medial body portion obfuscating flange positioned substantially axially parallel with the longitudinal axis of the medial body portion of the optically trackable body and positioned and sized to optically separate each indicator of the plurality of indicators mounted to the distal body end portion of the optically trackable body from each indicator of the plurality of indicators mounted to the medial body portion of the optically trackable body to prevent each indicator of the plurality of indicators mounted to the distal body portion of the optically trackable body from becoming optically coincident with each other indicator of the plurality of indicators mounted to the medial body portion of the optically trackable body, when viewed along either of the plurality of viewing paths extending directly through each indicator of the plurality of indicators mounted to the distal body portion of the optically trackable body and either indicator of the plurality of indicators mounted to the medial body portion of the optically trackable body.

14. A tracker as defined in claim 11, wherein the distal body end portion of the optically trackable body has a pair of adjacent indicators mounted thereto, and wherein the plurality of obfuscating flanges includes a distal body end portion obfuscating flange positioned substantially axially perpendicular to the longitudinal axis of the medial body portion of the optically trackable body and positioned and sized to optically separate a first indicator of the pair of indicators mounted to the distal body end portion of the optically trackable body from a second indicator of the pair of indicators mounted to the distal body portion of the optically trackable body to prevent the first indicator of the pair of adjacent indicators mounted to the distal body end portion of the optically trackable body from becoming optically coincident with the second indicator of the pair of indicators mounted to the distal body end portion of the optically trackable body, when viewed along either of the plurality of viewing paths extending directly through the first and second indicators of the pair of adjacent indicators mounted to the distal body end portion of the optically trackable body.

15. A tracker as defined in claim 11, wherein each indicator in the plurality of indicators is positioned to form at least two of the plurality of geometric figures to reduce a selected number of indicators required to determine the positional location and orientation of the movable object to thereby reduce overall size and complexity of the optically trackable body.

16. A tracker as defined in claim 11, further comprising a mounting connector adapted to connect the optically trackable body to the movable object, and wherein the optically trackable body further includes an interior mount recess inwardly extending from the proximal body end portion into the medial body portion and adapted to slidably receive at least portions of the mounting connector, when so positioned.

17. A tracker as defined in claim 16, wherein the medial body portion of the optically trackable body further includes a mounting connector retention recess extending between outer surface portions of the medial body portion and inner surface portions of the interior mount recess and positioned substantially normal to the interior mount recess to house at least portions of a mounting connector retention member, and wherein the mounting connector includes an annular mounting connector recess adapted to receive at least portions of the mounting connector retention member to fixedly retain the mounting connector within the interior mount recess when so positioned.

18. A tracker as defined in claim 16, wherein the medial body portion of the optically trackable body further includes a mounting connector retention recess extending between outer surface portions of the medial body portion and inner surface portions of the interior mount recess and positioned substantially normal to the interior mount recess, and a collapsible mounting connector retention lock member housed at least partially within the mounting connector retention recess and adapted to extend through inner surface portions of the interior mount recess when the mounting connector is substantially extended inward within the interior mount recess defining at least a partially-collapsed and inwardly biased lock position, adapted to collapse outward responsive to an outward pressure from the mounting connector when the mounting connector is partially retracted outward from within the interior mount recess defining a collapsed and unlocked position, and adapted to extend inward through the inner surface portions of the interior mount recess when the mounting connector is substantially retracted outward from within the interior mount recess defining a non-collapsed and inwardly biased unlocked position.

19. A tracker as defined in claim 11, wherein the optically trackable body further includes a proximal body end mounting extension connected to and integral with the proximal body end portion of the body, substantially extending perpendicular to and outwardly from the longitudinal axis of the optically trackable body, and having a substantially flat planer proximal surface adapted to interface with a surface of at least one of the movable object and a movable object mount.

20. A tracker as defined in claim 19, wherein the proximal body end mounting extension includes at least one longitudinal recess parallel to and spaced radially apart from the longitudinal axis of the optically trackable body and adapted to receive at least portions of at least one of the movable object mount and a mount alignment key adapted to angularly compel the proximal body end mounting extension of the optically trackable body in a predetermined position with respect to at least one of the movable object and the movable object mount to thereby prevent the optically trackable body from being mounted to the at least one of the movable object and the movable object mount in an incorrect orientation.

21. A tracker to provide three-dimensional positional data and orientation data about a positional location and orientation of a movable medical tool, the tracker comprising:

an optically trackable body adapted to connect to the movable medical tool, having a plurality of indicators mounted thereto and having a proximal body end portion, a distal body end portion, a medial body portion connected to and extending between the proximal body end portion and the distal body end portion, a body longitudinal axis, and at least one obfuscating flange sized and positioned to optically separate a first of the plurality of optical indicators from a second of the plurality of indicators to prevent the first of the plurality of indicators from becoming optically coincident with the second of the plurality of indicators when viewed along a viewing path extending directly through the first and second indicators to thereby enhance optical detection of the plurality of indicators.

22. A tracker as defined in claim 21, wherein the at least one obfuscating flange includes a plurality of longitudinal medial body portion obfuscating flanges sized and positioned substantially parallel to and spaced apart from the longitudinal axis of the medial body portion of the optically trackable body to optically separate each indicator of the plurality of indicators mounted to the medial body portion of the optically trackable body from each adjacent indicator of the plurality of indicators also mounted to the medial body portion of the optically trackable body to prevent each indicator of the plurality of indicators mounted to the medial body portion of the optically trackable body from becoming optically coincident with each adjacent indicator of the plurality of indicators also mounted to the medial body portion of the optically trackable body, when viewed along either of a plurality of viewing paths extending directly through each adjacent pair of the plurality of indicators mounted to the medial body portion of the optically trackable body.

23. A tracker as defined in claim 22, wherein the at least one obfuscating flange includes a medial body portion obfuscating flange positioned substantially axially parallel with the longitudinal axis of the medial body portion of the optically trackable body and positioned and sized to optically separate each indicator of the plurality of indicators mounted to the distal body end portion of the optically trackable body from each indicator of the plurality of indicators mounted to the medial body portion of the optically trackable body to prevent each indicator of the plurality of indicators mounted to the distal body portion of the optically trackable body from becoming optically coincident with each indicator of the plurality of indicators mounted to the medial body portion of the optically trackable body, when viewed along either of a plurality of viewing paths extending directly through each indicator of the plurality of indicators mounted to the distal body portion of the optically trackable body and either indicator of the plurality of indicators mounted to the medial body portion of the optically trackable body.

24. A tracker as defined in claim 22, wherein the distal body end portion of the optically trackable body has a pair of adjacent indicators mounted thereto, and wherein the plurality of obfuscating flanges includes a distal body end portion obfuscating flange positioned substantially axially perpendicular to the longitudinal axis of the medial body portion of the optically trackable body and positioned and sized to optically separate a first indicator of the pair of indicators mounted to the distal body end portion of the optically trackable body from a second indicator of the pair of indicators mounted to the distal body portion of the optically trackable body to prevent the first indicator of the pair of adjacent indicators mounted to the distal body end portion of the optically trackable body from becoming optically coincident with the second indicator of the pair of indicators mounted to the distal body end portion of the optically trackable body, when viewed along a viewing path extending directly through the first and second indicators of the pair of adjacent indicators mounted to the distal body end portion of the optically trackable body.

25. A tracker as defined in claim 21, further comprising a mounting connector adapted to connect the optically trackable body to the movable medical tool, and wherein the optically trackable body further includes an interior mount recess inwardly extending from the proximal body end portion into the medial body portion and adapted to slidably receive at least portions of the mounting connector, when so positioned.

26. A tracker as defined in claim 25, wherein the medial body portion of the optically trackable body further includes a mounting connector retention recess extending between outer surface portions of the medial body portion and inner surface portions of the interior mount recess and positioned substantially normal to the interior mount recess to house at least portions of a mounting connector retention member, and wherein the mounting connector includes a radial mounting connector recess extending from outer surface portions of the mounting connector radially within the mounting connector and adapted to receive at least portions of the mounting connector retention member to fixedly retain the mounting connector within the interior mount recess when so positioned.

27. A tracker as defined in claim 21, wherein the proximal body end portion of the optically trackable body further includes a proximal body end mounting extension connected to and integral with the proximal body end portion of the body, extending substantially perpendicular to and outwardly from the longitudinal axis of the optically trackable body and having a substantially flat planer proximal surface adapted to interface with a surface of at least one of the movable medical tool and a movable medical tool mount.

28. A tracker as defined in claim 27, wherein the proximal body end mounting extension includes at least one longitudinal recess parallel to and spaced radially apart from the longitudinal axis of the optically trackable body and adapted to receive at least portions of at least one of the movable medical tool mount and a mount alignment key adapted to axially compel the proximal body end mounting extension of the optically trackable body in a predetermined axial position with respect to at least one of the movable medical tool and the movable medical tool mount to thereby prevent the optically trackable body from being mounted to the at least one of the movable medical tool and the movable medical tool mount in an incorrect orientation.

29. A tracker as defined in claim 25, wherein the proximal body end portion of the optically trackable body further includes a proximal body end mounting extension connected to and integral with the proximal body end portion of the body, extending substantially perpendicular to and extending outwardly from the longitudinal axis of the optically trackable body, and having a substantially flat planer proximal surface adapted to interface with a surface of at least one of the movable medical tool and a movable medical tool mount, and a mounting connector retention recess extending between outer surface portions of the proximal body end mounting extension and inner surface portions of the interior mount recess and positioned substantially normal to the interior mount recess to house at least portions of a mounting connector retention member, and wherein the mounting connector includes a radial mounting connector recess extending from outer surface portions of the mounting connector radially within the mounting connector and adapted to receive at least portions of the mounting connector retention member to fixedly retain the mounting connector within the interior mount recess, when so positioned.

30. A tracker as defined in claim 21, further comprising a plurality of separate and spaced apart indicator mounts having a dissimilar, preselected length between each pair combination of the plurality of mounts and extending radially outward from the body longitudinal axis about a circumference of the optically trackable body and adapted to mount the plurality of indicators to the optically trackable body, and wherein the plurality of indicators provide three-dimensional positional data and orientation data of the optically trackable body for substantially all possible movable object orientations.

31. A method for tracking a position and an orientation of a movable object, comprising the steps of:

(a) connecting an optically trackable body to the movable object, the optically trackable body including a plurality of indicators positioned to form a plurality of geometric figures and including at least one obfuscating flange sized and positioned to optically separate a first of the plurality of indicators from a second of the plurality of indicators;

(b) viewing one of the plurality of geometric figures positioned in a field of view of an optical detector;

(c) identifying which one of the plurality of geometric figures is positioned in a field of view of the optical detector;

(d) analyzing the position and orientation of the identified geometric figure in the field of view of the optical detector to thereby determine the position and orientation of the movable object;

(e) continuously analyzing the position and orientation of the geometric figure to continuously re-determine the position and orientation of the movable object while the geometnc figure remains in the field of view of the optical detector; and

(f) obfuscating the first of the plurality of indicators to prevent the first of the plurality of indicators from becoming optically coincident with the second of the plurality of indicators, thereby replacing the geometric figure positioned in the field of view of the optical detector with another geometric figure.

32. A method of enhancing detection of a trackable body, the method comprising the steps of:

(a) positioning an obfuscating flange on a trackable body having a plurality of optical indicators to optically separate a first of the plurality of optical indicators from a second of the plurality of optical indicators; and

(b) inhibiting the first of the plurality of optical indicators from becoming optically coincident with the second of the plurality of optical indicators when viewing the trackable body along a preselected viewing path extending through the first and the second of the plurality of optical indicators by obfuscating the first of the plurality of optical indicators from the second of the plurality of optical detectors with the obfuscating flange.

33. A method for tracking a position and an orientation of a movable object, comprising the steps of:

connecting an optically trackable body having a plurality of indicators to the movable object, the optically trackable body including a first obfuscating flange sized and positioned to optically separate a first of the plurality of indicators from a second of the plurality of indicators and a second obfuscating flange sized and positioned to optically separate the second of the plurality of indicators from a third of the plurality of indicators;

obfuscating the first of the plurality of indicators to prevent the first of the plurality of indicators from becoming optically coincident with the second of the plurality of indicators;

viewing a subset of the plurality of indicators in a field of view of an optical detector;

identifying which of the plurality of indicators are positioned in the field of view of the optical detector;

analyzing the position of at least three of the plurality of indicators in the field of view of the optical detector to determine the position and orientation of the movable object;

rotating the optically trackable body;

obfuscating the third of the plurality of indicators to prevent the second of the plurality of indicators from becoming optically coincident with the third of the plurality of indicators, thereby replacing the subset of the plurality of indicators in the field of view of the optical detector with a different subset of the plurality of indicators; and

analyzing the position of at least three of the plurality of indicators in the field of view of the optical detector responsive to the steps of rotating and obfuscating to determine the position and orientation of the movable object, the steps of rotating and obfuscating being performed with a varying subset of at least three of the plurality of indicators to continuously re-determine the position and orientation of the movable object when the subset of at least three of the plurality of indicators remains in the field of view of the optical detector.