Redundant reciprocal tracking system

Abstract

The present invention relates to a redundant reciprocal tracking system composed of at least two trackers 10. A first tracker is able to sense partial or full pose data (orientation and position) of a second tracker in a first reference frame and the second tracker is able to sense partial or full pose data of the first tracker in a second reference frame. Pose data of first and second trackers are further transferred to a central processor 30, which is able to compute the transformation between first and second reference frame. Data generated by the trackers are such designed that they define an over-determined mathematical system (e.g. more than 6 degrees of freedom in a 3D setup). The over-determined information can be used to qualify and/or improve the transformation of the reference frame. In an embodiment of the invention, the tracking system is an optical one and the over-determined information defines an error metric used to check the validity of the transformation. Such setup could be used in surgical navigation system in order to reduce the risk of injury or death of the patient.

1 - 32 . (canceled) 
     
     
         33 . A first tracker device, comprising:
 at least one optical sensor module comprising at least one image sensor and at least one reticule disposed proximate the at least one image sensor;   memory comprising instructions stored thereon; and   at least one processor coupled to the memory and the at least one optical sensor module and configured to execute the stored instructions to:
 generate positional information of a second tracker device in a first reference frame of the first tracker device based on a shadow cast by the at least one reticule on the at least one image sensor upon illumination of at least one sensed element of the second tracker device; and 
 outputting the positional information via at least one communication link to facilitate determination of one or more of a pose of the second tracker device with respect to the first reference frame or a rigid transformation of the first reference frame relative to a second reference frame of the second tracker device. 
   
     
     
         34 . The first tracker device according to  claim 33 , wherein the at least one processor is further configured to execute the stored instructions to output the positional information via the at least one communication link to one or more of:
 a central processor; or   one or more third tracker devices to facilitate distributed processing of the positional information.   
     
     
         35 . The first tracker device according to  claim 33 , wherein the positional information comprises at least a horizontal angular position and a vertical angular position of the at least one sensed element of the second tracker device. 
     
     
         36 . The first tracker device according to  claim 33 , wherein the at least one sensed element of the second tracker device comprises at least three light sources and the at least one processor is further configured to execute the stored instructions to detect a position in three dimensions of the at least three light sources upon sequential illumination of the at least three light sources. 
     
     
         37 . The first tracker device according to  claim 33 , wherein the at least one processor is further configured to execute the stored instructions to generate the positional information based on a first shadow and a second shadow cast by the at least one reticule on a first portion and a second portion, respectively, of the at least one image sensor upon illumination of the at least one sensed element of the second tracker device. 
     
     
         38 . The first tracker device according to  claim 33 , wherein the at least one optical sensor module comprises two optical sensor modules and the first tracker device further comprises a reference frame on which the optical sensor modules are disposed at a known position and orientation. 
     
     
         39 . The first tracker device according to  claim 33 , further comprising at least three light sources, wherein the at least one processor is further configured to execute the stored instructions to sequentially illuminate each of the at least three light sources to facilitate generation of additional positional information of the first tracker device by the second tracker device. 
     
     
         40 . A method for reciprocal optical tracking, the method comprising:
 generating, by a first tracker device, positional information of a second tracker device in a first reference frame of the first tracker device based on a shadow cast by at least one reticule of at least one optical sensor module of the first tracker device on at least one image sensor of the at least one optical module upon illumination of at least one sensed element of the second tracker device; and   outputting, by the first tracker device, the positional information via at least one communication link to facilitate determination of one or more of a pose of the second tracker device with respect to the first reference frame or a rigid transformation of the first reference frame relative to a second reference frame of the second tracker device.   
     
     
         41 . The method according to  claim 40 , further comprising outputting, by the first tracker device, the positional information via the at least one communication link to one or more of:
 a central processor; or   one or more third tracker devices to facilitate distributed processing of the positional information.   
     
     
         42 . The method according to  claim 40 , wherein the positional information comprises at least a horizontal angular position and a vertical angular position of the at least one sensed element of the second tracker device. 
     
     
         43 . The method according to  claim 40 , wherein the at least one sensed element of the second tracker device comprises at least three light sources and the method further comprises detecting, by the first tracker device, a position in three dimensions of the at least three light sources upon sequential illumination of the at least three light sources. 
     
     
         44 . The method according to  claim 40 , further comprising generating, by the first tracker device, the positional information based on a first shadow and a second shadow cast by the at least one reticule on a first portion and a second portion, respectively, of the at least one image sensor upon illumination of the at least one sensed element of the second tracker device. 
     
     
         45 . The method according to  claim 40 , wherein the at least one optical sensor module comprises two optical sensor modules and the first tracker device further comprises a reference frame on which the optical sensor modules are disposed at a known position and orientation. 
     
     
         46 . The method according to  claim 40 , further comprising sequentially illuminating, by the first tracker device, each of at least three light sources to facilitate generation of additional positional information of the first tracker device by the second tracker device. 
     
     
         47 . A non-transitory computer readable medium having stored thereon instructions for reciprocal optical tracking and comprising executable code that, when executed by at least one processor, causes the at least one processor to:
 generate positional information of a second tracker device in a first reference frame of a first tracker device based on a shadow cast by at least one reticule of at least one optical sensor module of the first tracker device on at least one image sensor of the at least one optical module upon illumination of at least one sensed element of the second tracker device; and   output the positional information via at least one communication link to facilitate determination of one or more of a pose of the second tracker device with respect to the first reference frame or a rigid transformation of the first reference frame relative to a second reference frame of the second tracker device.   
     
     
         48 . The non-transitory computer readable medium of  claim 47 , wherein the executable code, when executed by the at least one processor, further causes the at least one processor to output the positional information via the at least one communication link to one or more of:
 a central processor; or   one or more third tracker devices to facilitate distributed processing of the positional information.   
     
     
         49 . The non-transitory computer readable medium of  claim 47 , wherein the positional information comprises at least a horizontal angular position and a vertical angular position of the at least one sensed element of the second tracker device. 
     
     
         50 . The non-transitory computer readable medium of  claim 47 , wherein the at least one sensed element of the second tracker device comprises at least three light sources and the executable code, when executed by the at least one processor, further causes the at least one processor to detect a position in three dimensions of the at least three light sources upon sequential illumination of the at least three light sources. 
     
     
         51 . The non-transitory computer readable medium of  claim 47 , wherein the executable code, when executed by the processors, further causes the at least one processor to generate the positional information based on a first shadow and a second shadow cast by the at least one reticule on a first portion and a second portion, respectively, of the at least one image sensor upon illumination of the at least one sensed element of the second tracker device. 
     
     
         52 . The non-transitory computer readable medium of  claim 47 , wherein the executable code, when executed by the processors, further causes the at least one processor to sequentially illuminate each of at least three light sources to facilitate generation of additional positional information of the first tracker device by the second tracker device.