Optimization of tracker-based surgical navigation

Abstract

A system and method for optimizing tracking of a target within a surgical workspace. A tracker is positioned relative to a target having markers of predefined geometry to track the pose of the tracker within the surgical workspace. A localizer camera cooperates with the tracker to generate image data indicative of respective blobs of the markers generated from optical signals received from the markers. Characteristics of each blob are obtained and compared to optimal characteristics. Based on the comparison, the operation of the tracker, the operation of the localizer, or both, is adjusted to optimize the blobs generated from the markers.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 190,791, filed May 20, 2021, the entire disclosure of which is incorporated herein by reference. [Background technology]

[0002] Conventional surgical navigation systems track targets within a surgical workspace by imaging fiducials attached to the targets and calculating the positions of such fiducials within the surgical workspace from the imaging. Suboptimal lighting can affect the ability of the surgical navigation system to accurately determine the position of each fiducial, which in turn can affect tracking accuracy. Summary of the Invention [Problem to be solved by the invention]

[0003] This Summary introduces a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to limit the scope of the claimed subject matter, nor does it necessarily identify key or essential features of each claimed subject matter. [Means for solving the problem]

[0004] In a first aspect, a navigation system for optimizing tracking of a target within a surgical workspace is provided. The navigation system includes a tracker positioned relative to the target, the tracker having active markers of predefined geometry for tracking a pose of the tracker within the surgical workspace, a localizer camera configured to cooperate with the tracker to generate image data indicative of blobs of each of the active markers generated from optical signals emitted from the active markers, and a controller communicatively coupled to the tracker and the localizer camera. The controller is configured to assign each of the blobs to a corresponding active marker, acquire characteristics of each blob, compare the acquired characteristics to optimal characteristics, and, based on the comparison, communicate at least one control signal to the tracker that causes the tracker to adjust an optical signal emitted from at least one of the active markers.

[0005] In a second aspect, a navigation system for optimizing tracking of a target within a surgical workspace is provided, the navigation system including: a first tracker positioned relative to a first target within the surgical workspace, the first tracker having active markers of predefined geometry for tracking a pose of the first tracker within the surgical workspace; a second tracker positioned relative to a second target within the surgical workspace, the second tracker having active markers of predefined geometry for tracking a pose of the second tracker within the surgical workspace; a localizer camera configured to cooperate with the first and second trackers to generate image data indicative of a first blob for each of the active markers of the first tracker generated from optical signals emitted from the active markers and a second blob for each of the active markers of the second tracker generated from optical signals emitted from the active markers; and a controller communicatively coupled to the first and second trackers and the localizer camera. The controller is configured to acquire characteristics of each of the first and second blobs, compare the acquired characteristics to a first optimal characteristic characteristic of the first tracker and a second optimal characteristic characteristic of the second tracker that is different from the first optimal characteristic, and assign the first blob to the first tracker and the second blob to the second tracker based on the comparison.

[0006] In a third aspect, a navigation system for optimizing tracking of a target within a surgical workspace is provided. The navigation system includes a tracker positioned relative to the target, the tracker having active markers of predefined geometry for tracking a pose of the tracker within the surgical workspace, a localizer camera configured to cooperate with the tracker to generate image data indicative of each blob of the active markers generated from optical signals emitted from the active markers, and a controller communicatively coupled to the tracker and the localizer camera. The controller is configured to determine positions of the active markers of the tracker within the surgical workspace based on the image data and to communicate at least one control signal to the tracker that causes the tracker to adjust the optical signal emitted from at least one of the active markers based on the determined positions of the active markers.

[0007] In a fourth aspect, a navigation system for optimizing tracking of a target within a surgical workspace is provided, the navigation system including: a tracker positioned relative to the target, the tracker having passive markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit optical signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of blobs of the passive markers generated from reflections by the passive markers of the optical signals emitted from the light source; and a controller communicatively coupled to the localizer camera, the controller configured to acquire characteristics of each blob, compare the acquired characteristics to optimal characteristics, and adjust at least one optical parameter of the localizer camera based on the comparison.

[0008] In a fifth aspect, there is provided a navigation system for tracking a target within a surgical workspace, the navigation system including: a first tracker positioned relative to a first target within the surgical workspace, the first tracker including passive markers of predefined geometry for tracking a pose of the first tracker within the surgical workspace, a second tracker positioned relative to a second target within the surgical workspace, the second tracker including passive markers of predefined geometry for tracking a pose of the second tracker within the surgical workspace, a localizer camera including a light source configured to emit light signals to illuminate the passive markers of the first and second trackers, the localizer camera configured to generate image data indicative of respective blobs of the passive markers of the first and second trackers generated from reflections of the passive markers of the light signals emitted from the light source, and a controller communicatively coupled to the localizer camera. The controller is configured to emit a first optical signal from a light source that is specific to the first tracker, receive image data generated by a localizer camera corresponding to the emitted first optical signal, and track a pose of the first tracker within the surgical workspace based on the received image data corresponding to the first optical signal. The controller is further configured to emit a second optical signal from the light source that is specific to a second tracker and has at least one characteristic different from the at least one corresponding characteristic of the first optical signal, receive image data generated by the localizer camera corresponding to the emitted second optical signal, and track a pose of the second tracker within the surgical workspace based on the received image data corresponding to the second optical signal.

[0009] In a sixth aspect, a navigation system for optimizing tracking of a target within a surgical workspace is provided, the navigation system including: a tracker positioned relative to the target, the tracker having passive markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit light signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of respective blobs of the passive markers generated from reflections by the passive markers of the light signals emitted from the light source; and a controller communicatively coupled to the localizer camera. The controller is configured to emit light signals having varying characteristics from the light source, receive image data generated by the localizer camera for each emitted light signal indicative of a respective blob of the passive marker generated from reflection of the emitted light signals by the passive marker, obtain, for each instance of the received image data, a characteristic of each blob indicated by the image data, compare the obtained characteristic with an optimal characteristic to determine which of the instances of the received image data is closest to the optimal, and in response to determining which instance of the received image data is closest to the optimal, assign to the tracker the light signal characteristic corresponding to the instance of the received image data, and track the orientation of the tracker within the surgical workspace based on the light signal characteristic assigned to the tracker.

[0010] In a seventh aspect, a navigation system for optimizing tracking of a target within a surgical workspace is provided, the navigation system including: a tracker positioned relative to the target, the tracker having passive markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit optical signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of each blob of the passive markers generated from reflections by the passive markers of the optical signals emitted from the light source; and a controller communicatively coupled to the localizer camera. The controller is configured to determine positions of the passive markers of the tracker within the surgical workspace based on the image data and adjust at least one optical parameter of the localizer camera based on the determined positions of the passive markers.

[0011] In an eighth aspect, a navigation system for optimizing tracking of a target within a surgical workspace is provided, the navigation system including: a tracker positioned relative to the target, the tracker having passive markers of predefined geometries that can be manually repositioned to track the orientation of the tracker within the surgical workspace; a localizer camera including a light source configured to emit optical signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of each blob of the passive markers generated from reflections by the passive markers of the optical signals emitted from the light source; and a controller communicatively coupled to the localizer camera, the controller configured to acquire characteristics of each blob, compare the acquired characteristics to optimal characteristics, and, based on the comparison, determine and display guidance for repositioning the passive markers of the tracker.

[0012] In a ninth aspect, a method for optimizing tracking of a target within a surgical workspace by a navigation system is provided. The navigation system includes a tracker positioned relative to the target, the tracker having active markers of predefined geometries for tracking a pose of the tracker within the surgical workspace, a localizer camera configured to cooperate with the tracker to generate image data indicative of each blob of the active markers generated from optical signals emitted from the active markers, and a controller communicatively coupled to the tracker and the localizer camera. The method includes positioning the tracker relative to the target within the surgical workspace, generating, by the localizer camera, image data indicative of each blob of the active markers generated from optical signals emitted from the active markers, assigning, by the controller, each of the blobs to its corresponding active marker, acquiring, by the controller, characteristics of each blob, comparing, by the controller, the acquired characteristics to optimal characteristics, and, based on the comparison, communicating, by the controller, at least one control signal to the tracker that causes the tracker to adjust an optical signal emitted from at least one of the active markers.

[0013] In a tenth aspect, a method is provided for optimizing tracking of a target within a surgical workspace by a navigation system, the navigation system including: a first tracker positioned relative to a first target within the surgical workspace, the first tracker having active markers of predefined geometry for tracking a pose of the first tracker within the surgical workspace, a second tracker positioned relative to a second target within the surgical workspace, the second tracker having active markers of predefined geometry for tracking a pose of the second tracker within the surgical workspace, a localizer camera configured to cooperate with the first and second trackers to generate image data indicative of blobs of the active markers of each of the first and second trackers generated from optical signals emitted from the active markers, and a controller communicatively coupled to the first and second trackers and the localizer camera. The method includes positioning first and second trackers relative to first and second targets, respectively, within a surgical workspace; generating, by a localizer camera, image data indicative of blobs of each of the active markers of the first and second trackers generated from optical signals emitted from the active markers; acquiring, by a controller, characteristics of each of the first and second blobs; comparing, by the controller, the acquired characteristics to a first optimal characteristic characteristic of the first tracker and a second optimal characteristic characteristic of the second tracker, the second optimal characteristic being different from the first optimal characteristic; and assigning, by the controller, the first blob to the first tracker and the second blob to the second tracker based on the comparison.

[0014] In an eleventh aspect, a method for optimizing tracking of a target within a surgical workspace by a navigation system is provided. The navigation system includes a tracker positioned relative to the target, the tracker having active markers of predefined geometries for tracking a pose of the tracker within the surgical workspace, a localizer camera configured to cooperate with the tracker to generate image data indicative of each blob of the active markers generated from optical signals emitted from the active markers, and a controller communicatively coupled to the tracker and the localizer camera. The method includes positioning the tracker relative to the target within the surgical workspace, generating, by the localizer camera, image data indicative of each blob of the active markers generated from optical signals emitted from the active markers, determining, by the controller, positions of the active markers for the tracker within the surgical workspace based on the image data, and communicating, by the controller, at least one control signal to the tracker based on the determined positions of the active markers, the control signal causing the tracker to adjust the optical signals emitted from at least one of the active markers.

[0015] In a twelfth aspect, a method is provided for optimizing tracking of a target within a surgical workspace by a navigation system. The navigation system includes: a tracker positioned relative to the target, the tracker having passive markers of predefined geometries for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit optical signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of blobs of the passive markers generated from reflections of the optical signals emitted from the light source by the passive markers; and a controller communicatively coupled to the localizer camera. The method includes positioning the tracker relative to the target within the surgical workspace; generating, by the localizer camera, image data indicative of each blob of the passive markers generated from reflections of the optical signals emitted from the light source by the passive markers; acquiring, by the controller, characteristics of each blob; comparing, by the controller, the acquired characteristics to optimal characteristics; and adjusting, by the controller, at least one optical parameter of the localizer camera based on the comparison.

[0016] In a thirteenth aspect, there is provided a method for optimizing tracking of a target within a surgical workspace by a navigation system, the navigation system including: a first tracker positioned relative to a first target within the surgical workspace, the first tracker having passive markers of predefined geometry for tracking a pose of the first tracker within the surgical workspace; a second tracker positioned relative to a second target within the surgical workspace, the second tracker having passive markers of predefined geometry for tracking a pose of the second tracker within the surgical workspace; a localizer camera including a light source configured to emit light signals to illuminate the passive markers of the first and second trackers, the localizer camera configured to generate image data indicative of respective blobs of the passive markers of the first and second trackers generated from reflections of the passive markers of the light signals emitted from the light source; and a controller communicatively coupled to the localizer camera. The method includes positioning first and second trackers relative to first and second landmarks, respectively, within a surgical workspace, emitting a first optical signal from a light source that is specific to the first tracker, receiving, by a controller, image data generated by a localizer camera that corresponds to the emitted first optical signal, and tracking, by the controller, a pose of the first tracker within the surgical workspace based on the received image data corresponding to the first optical signal. The method further includes emitting a second optical signal from the light source that is specific to a second tracker and has at least one characteristic different from the at least one corresponding characteristic of the first optical signal, receiving, by the controller, image data generated by the localizer camera that corresponds to the emitted second optical signal, and tracking, by the controller, a pose of the second tracker within the surgical workspace based on the received image data corresponding to the second optical signal.

[0017] In a fourteenth aspect, a method is provided for optimizing tracking of a target within a surgical workspace by a navigation system, the navigation system including: a tracker positioned relative to the target, the tracker having passive markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit optical signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of respective blobs of the passive markers generated from reflections by the passive markers of the optical signals emitted from the light source; and a controller communicatively coupled to the localizer camera. The method includes positioning a tracker relative to a target within a surgical workspace; emitting light signals having varying characteristics from a light source; receiving, by a controller, image data generated by a localizer camera for each of the emitted light signals indicative of respective blobs of passive markers generated from reflection of the emitted light signals by the passive markers; for each instance of the received image data, obtaining, by the controller, a characteristic of each blob indicated by the image data, and comparing, by the controller, the obtained characteristic with an optimal characteristic to determine which of the instances of the received image data is closest to optimal; in response to determining which instance of the received image data is closest to optimal, assigning, by the controller, to the tracker the light signal characteristic corresponding to the instance of the received image data; and tracking, by the controller, a pose of the tracker within the surgical workspace based on the light signal characteristic assigned to the tracker.

[0018] In a fifteenth aspect, a method is provided for optimizing tracking of a target object within a surgical workspace by a surgical navigation system. The navigation system includes: a tracker positioned relative to the target object, the tracker having passive markers of predefined geometries for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit optical signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of each blob of the passive markers generated from reflections of the optical signals emitted from the light source by the passive markers; and a controller communicatively coupled to the localizer camera. The method includes positioning the tracker relative to the target object within the surgical workspace; generating, by the localizer camera, image data indicative of each blob of the passive markers generated from reflections of the optical signals emitted from the light source by the passive markers; determining, by the controller, positions of the passive markers of the tracker within the surgical workspace based on the image data; and adjusting, by the controller, at least one optical parameter of the localizer camera based on the determined positions of the passive markers.

[0019] In a sixteenth aspect, a method is provided for optimizing tracking of a target within a surgical workspace by a navigation system. The navigation system includes: a tracker positioned relative to the target, the tracker having passive markers of predefined geometries repositionable to track a posture of the tracker within the surgical workspace; a localizer camera including a light source configured to emit optical signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of each blob of the passive markers generated from reflections of the optical signals emitted from the light source by the passive markers; and a controller communicatively coupled to the localizer camera. The method includes positioning the tracker relative to the target within the surgical workspace; generating, by the localizer camera, image data indicative of each blob of the passive markers generated from reflections of the optical signals emitted from the light source by the passive markers; acquiring, by the controller, characteristics of each blob; comparing, by the controller, the acquired characteristics to optimal characteristics; and determining and displaying, by the controller, guidance for repositioning the passive markers of the tracker based on the comparison.

[0020] In a seventeenth aspect, there is provided a robotic surgical system including a robotic device configured to support a surgical tool and one or more controllers configured to implement the methods of any one or more of the ninth to sixteenth aspects, wherein the one or more controllers are configured to control the robotic device to move the surgical tool relative to a cutting boundary to remove a target volume of patient tissue.

[0021] Any of the above aspects may be combined in whole or in part.

[0022] Any of the above aspects may be utilized with any one or more of the following embodiments, whether utilized individually or in combination.

[0023] Some embodiments include at least one control signal communicated to the tracker causing the tracker to adjust an intensity and / or duration of an optical signal emitted from at least one of the active markers. Some embodiments include, for each of the blobs, comparing the obtained characteristics of the blob to an optimal characteristic to determine whether the blob is suboptimal, and in response to determining that the blob is suboptimal based on the comparison, communicating a control signal to the tracker that causes the tracker to adjust an optical signal emitted from the active marker corresponding to the blob.

[0024] Some embodiments include: the obtained characteristic of each blob exhibiting a first value and the optimal characteristic exhibiting a second value; comparing the exhibited first value for the blob to the second value; and, in response to the comparison indicating that the first value for the blob is greater than the second value, communicating a control signal to the tracker that causes the tracker to reduce an intensity and / or duration of an optical signal emitted from the active marker corresponding to the blob; and, in response to the comparison indicating that the first value for the blob is less than the second value, communicating a control signal to the tracker that causes the tracker to increase an intensity and / or duration of an optical signal emitted from the active marker corresponding to the blob.

[0025] Some embodiments include the obtained characteristic being a blob intensity characteristic and the optimal characteristic being an optimal blob intensity characteristic. Some embodiments include the optimal blob intensity characteristic exhibiting a value greater than or equal to 75% and less than or equal to 95% of the full intensity value of the localizer camera. Some embodiments include the obtained characteristic being a blob size characteristic and the optimal characteristic being an optimal blob size characteristic. Some embodiments include the obtained characteristic being a blob shape characteristic and the optimal characteristic being an optimal blob shape characteristic.

[0026] Some embodiments include: acquiring one or more second characteristics of one or more of the blobs, where the acquired characteristic is defined as an acquired first characteristic, and the optimal characteristic is defined as a first optimal characteristic; comparing the one or more acquired second characteristics to the second optimal characteristic; and communicating at least one control signal to the tracker that causes the tracker to adjust an optical signal emitted from at least one of the one or more active markers corresponding to the one or more blobs based on a comparison of the one or more acquired second characteristics to the second optimal characteristic. Some embodiments include: the one or more acquired second characteristics including an acquired second characteristic of each of the one or more blobs; comparing, for each of the one or more blobs, the acquired second characteristic of the blob to the second optimal characteristic to determine whether the blob is suboptimal; and communicating a control signal to the tracker that causes the tracker to adjust an optical signal emitted from the active marker corresponding to the blob based on the comparison.

[0027] Some embodiments include: the acquired characteristic is defined as an acquired first characteristic; the optimal characteristic is defined as a first optimal characteristic; comparing the acquired first characteristic of the blob with the first optimal characteristic to determine if the acquired first characteristic of the blob is not best; and in response to determining, based on the comparison, that the acquired first characteristic of the blob is best, communicating a control signal to the tracker that causes the tracker to adjust an optical signal emitted from an active marker corresponding to the blob; and in response to determining, based on the comparison, that the acquired first characteristic of the blob is best, acquiring a second characteristic of the blob; comparing the acquired second characteristic of the blob with the second optimal characteristic to determine if the acquired second characteristic of the blob is not best; and in response to determining, based on the comparison, that the acquired second characteristic of the blob is not best, communicating a control signal to the tracker that causes the tracker to adjust an optical signal emitted from an active marker corresponding to the blob.

[0028] Some embodiments include the acquired first property being a blob intensity property and the acquired second property being a blob size property or a blob shape property. Some embodiments include the acquired first property being a blob size property and the acquired second property being a blob intensity property or a blob shape property. Some embodiments include the acquired first property being a blob shape property and the acquired second property being a blob intensity property or a blob size property.

[0029] Some embodiments include the image data including first image data corresponding to a first optical sensor of the localizer camera and second image data corresponding to a second optical sensor of the localizer camera, each of the first and second image data indicating a blob for each active marker generated from optical signals emitted from the active markers, and the method includes identifying a first blob from the first image data and a second blob from the second image data that correspond to the same active marker; obtaining a first characteristic of the first blob and a second characteristic of the second blob; combining the obtained first characteristic and the obtained second characteristic to form a combined blob characteristic; comparing the combined blob characteristic to an optimal characteristic to determine if the combined blob characteristic is not optimal; and, in response to determining, based on the comparison, that the combined blob characteristic is not optimal, communicating a control signal to the tracker that causes the tracker to adjust the optical signals emitted from the active markers corresponding to the first and second blobs.

[0030] Some embodiments include: the combined blob characteristic exhibiting a first value and the optimal characteristic exhibiting a second value; comparing the first value to the second value; and, in response to the comparison indicating the first value is greater than the second value, communicating a control signal to the tracker that causes the tracker to reduce the intensity and / or duration of optical signals emitted from the active markers corresponding to the first and second blobs; and, in response to the comparison indicating the first value is less than the second value, communicating a control signal to the tracker that causes the tracker to increase the intensity and / or duration of optical signals emitted from the active markers corresponding to the first and second blobs.

[0031] Some embodiments include the acquired first and second characteristics being acquired blob intensity characteristics, and the optimal characteristic being an optimal blob intensity characteristic. Some embodiments include the optimal blob intensity characteristic exhibiting a value greater than or equal to 75% and less than or equal to 95% of the localizer camera's full intensity value. Some embodiments include the acquired first and second characteristics being acquired size characteristics, and the optimal characteristic being an optimal blob size characteristic. Some embodiments include the acquired first and second characteristics being acquired shape characteristics, and the optimal characteristic being an optimal blob shape characteristic.

[0032] Some embodiments include: defining the combined blob characteristic as a first combined blob characteristic, defining the optimal characteristic as a first optimal characteristic, obtaining a third characteristic of the first blob and a fourth characteristic of the second blob, combining the obtained third characteristic and the obtained fourth characteristic to form a second combined blob characteristic, comparing the second combined blob characteristic to the second optimal characteristic, and communicating a control signal to the tracker that causes the tracker to adjust optical signals emitted from the active markers corresponding to the first and second blobs based on a comparison of the second combined blob characteristic to the second optimal characteristic. Some embodiments include comparing the second combined blob characteristic to the second optimal characteristic to determine if the second combined blob characteristic is suboptimal, and communicating a control signal to the tracker that causes the tracker to adjust optical signals emitted from the active markers corresponding to the first and second blobs in response to determining, based on the comparison, that the second combined blob is suboptimal.

[0033] Some embodiments include: defining the combined blob characteristic as a first combined blob characteristic; defining the optimal characteristic as a first optimal characteristic; comparing the first combined blob characteristic to the first optimal characteristic to determine if the first combined blob characteristic is not optimal; in response to determining that the first combined blob characteristic is not optimal, communicating a control signal to the tracker that causes the tracker to adjust optical signals emitted from the active markers corresponding to the first and second blobs; and in response to determining that the first combined blob characteristic is optimal based on the comparison. acquiring a third characteristic of the first blob and a fourth characteristic of the second blob; combining the acquired third characteristic and the acquired fourth characteristic to form a second combined blob characteristic; comparing the second combined blob characteristic to a second optimal characteristic to determine whether the second combined blob characteristic is not optimal; and in response to determining that the second combined blob characteristic is not optimal based on the comparison, communicating a control signal to the tracker that causes the tracker to adjust optical signals emitted from the active markers corresponding to the first and second blobs.

[0034] Some embodiments include the first and second acquired properties being blob intensity properties and the third and fourth acquired properties being blob size properties or blob shape properties. Some embodiments include the first and second acquired properties being blob size properties and the third and fourth acquired properties being blob intensity properties or blob shape properties. Some embodiments include the first and second acquired properties being blob shape properties and the third and fourth acquired properties being blob intensity properties or blob size properties.

[0035] Some embodiments include: the target object is defined as a first target object; the blob is defined as a first blob; the tracker is defined as a first tracker; the acquired characteristic is defined as the acquired first characteristic; the optimal characteristic is defined as a first optimal characteristic specific to the first tracker; a second tracker is positioned relative to the second target object within the surgical workspace and has active markers of predefined geometry for tracking a pose of the second tracker within the surgical workspace; and the image data generated by the localizer camera includes second blobs for each of the active markers of the second tracker generated from optical signals emitted from the active markers of the second tracker. Some embodiments further include assigning each of the second blobs to an active marker of the second tracker that corresponds to the second blob, obtaining a second characteristic of each second blob, comparing the obtained second characteristic to a second optimal characteristic that is specific to the second tracker and different from the first optimal characteristic, and communicating at least one control signal to the second tracker that causes the second tracker to adjust an optical signal emitted from at least one of the active markers of the second tracker based on the comparison.

[0036] Some embodiments include, for each second blob, comparing the obtained second characteristic of the second blob with a second optimal characteristic to determine whether the second blob is sub-optimal, and in response to determining that the second blob is sub-optimal based on the comparison, communicating a control signal to the second tracker that causes the second tracker to adjust an optical signal emitted from an active marker of the second tracker corresponding to the second blob.

[0037] Some embodiments include assigning the first blob to an active marker of the first tracker based on the first optimal characteristic. Some embodiments include, for each of the first blobs, determining a difference between the acquired first characteristic of the first blob and the first optimal characteristic, determining whether the difference between the acquired first characteristic of the first blob and the first optimal characteristic is less than a threshold, and in response to determining that the difference between the acquired first characteristic of the first blob and the first optimal characteristic is less than the threshold, determining that the first blob corresponds to the first tracker and assigning the first blob to the active marker of the first tracker corresponding to the first blob.

[0038] Some embodiments include assigning the second blob to an active marker of a second tracker based on the second optimal characteristic. Some embodiments include, for each second blob, determining a difference between the acquired second characteristic of the second blob and the second optimal characteristic, determining whether the difference between the acquired second characteristic of the second blob and the second optimal characteristic is less than a threshold, and in response to determining that the difference between the acquired second characteristic of the second blob and the second optimal characteristic is less than the threshold, determining that the second blob corresponds to the second tracker and assigning the second blob to an active marker of the second tracker corresponding to the second blob.

[0039] Some implementations include a predefined geometry of the active markers of the first tracker and a predefined geometry of the active markers of the second tracker that is substantially equivalent.

[0040] Some embodiments include determining positions of active markers of the tracker within the surgical workspace based on the image data, and communicating at least one control signal to the tracker that causes the tracker to adjust an optical signal emitted from at least one of the active markers based on the determined positions of the active markers. Some embodiments include, for each of the active markers, comparing the obtained characteristics of the blob corresponding to the active marker with an optimal characteristic to determine whether the blob corresponding to the active marker is suboptimal, and in response to determining that the blob corresponding to the active marker is suboptimal, communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the determined positions of the active marker.

[0041] Some embodiments include comparing the determined position of the active marker to a previously determined position of the active marker to determine a change in distance between the active marker and the localizer camera, counting a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the determined position of the active marker, and communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the change in distance. Some embodiments include communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the determined change in distance by determining whether the change in distance indicates an increase or a decrease in distance between the active marker and the localizer camera, communicating a control signal to the tracker that causes the tracker to increase the intensity and / or duration of the optical signal emitted from the active marker in response to a change in distance that indicates an increase in distance between the active marker and the localizer camera, and communicating a control signal to the tracker that causes the tracker to decrease the intensity and / or duration of the optical signal emitted from the active marker in response to a change in distance that indicates a decrease in distance between the active marker and the localizer camera.

[0042] Some embodiments include a tracker including at least one actuator for repositioning active markers of the tracker and communicating at least one control signal to the tracker that causes the tracker to reposition at least one of the active markers based on a comparison of the acquired characteristics to an optimal characteristic. Some embodiments include, for each of the blobs, comparing the acquired characteristics of the blob to the optimal characteristic to determine whether the blob is suboptimal, and in response to determining that the blob is suboptimal based on the comparison, communicating a control signal to the tracker that causes the tracker to reposition the active marker corresponding to the blob. Some embodiments include: the obtained characteristic of each blob exhibiting a first value and the optimal characteristic exhibiting a second value; for each blob, comparing the first value exhibited for the blob with the second value; and, in response to the comparison indicating that the first value for the blob is greater than the second value, communicating a control signal to the tracker that causes the tracker to reposition an active marker corresponding to the blob away from the localizer camera; and, in response to the comparison indicating that the first value for the blob is less than the second value, communicating a control signal to the tracker that causes the tracker to reposition the active marker corresponding to the blob toward the localizer camera.

[0043] Some embodiments include adjusting at least one optical parameter of the localizer camera based on the comparison by adjusting an optical signal emitted from the light source to illuminate the passive marker based on the comparison.Some embodiments include adjusting at least one optical parameter of the localizer camera based on the comparison by adjusting an intensity and / or duration of an optical signal emitted from the light source to illuminate the passive marker based on the comparison.

[0044] Some embodiments include combining the acquired characteristics to form a combined blob characteristic, comparing the combined blob characteristic to an optimal characteristic to determine if the combined blob characteristic is not optimal, and adjusting at least one optical parameter of the localizer camera in response to determining that the combined blob characteristic is not optimal based on the comparison. Some embodiments include: the combined blob characteristic exhibiting a first value and the optimal characteristic exhibiting a second value, comparing the first value to the second value, in response to the comparison indicating the first value is greater than the second value, reducing the intensity and / or duration of the optical signal emitted from the light source to illuminate the passive marker, and in response to the comparison indicating the first value is less than the second value, increasing the intensity and / or duration of the optical signal emitted from the light source to illuminate the passive marker.

[0045] Some embodiments include: the acquired characteristic is defined as a first acquired characteristic; the combined blob characteristic is defined as a first combined blob characteristic; the optimal characteristic is defined as a first optimal characteristic; comparing the first combined blob characteristic to the first optimal characteristic to determine whether the first combined blob characteristic is not optimal; adjusting at least one optical parameter of the localizer camera in response to determining, based on the comparison, that the first combined blob characteristic is not optimal; acquiring a second characteristic of each blob in response to determining, based on the comparison, that the first combined blob characteristic is best; combining the acquired second characteristics to form a second combined blob characteristic; comparing the second combined blob characteristic to the second optimal characteristic to determine whether the second combined blob characteristic is not optimal; and adjusting at least one optical parameter of the localizer camera in response to determining, based on the comparison, that the second combined blob characteristic is not optimal.

[0046] Some embodiments include: the target is defined as a first target; the blob is defined as a first blob; the tracker is defined as a first tracker; the optical signal is defined as a first optical signal specific to the first tracker; and the second tracker is positioned relative to the second target within the surgical workspace and has a passive marker of predefined geometry for tracking the orientation of the second tracker within the surgical workspace. Some embodiments further include emitting a second optical signal from a light source specific to the second tracker, the second optical signal having at least one characteristic that differs from at least one corresponding characteristic of the first optical signal; receiving image data corresponding to the second optical signal generated by a localizer camera, the received image data indicating a second blob for each of the passive markers of the second tracker generated from reflection by the passive markers of the second optical signal emitted from the light source; acquiring characteristics of each second blob; comparing the acquired characteristics of the second blobs with optimal characteristics to determine whether the acquired characteristics of the second blobs are suboptimal; and adjusting at least one characteristic of the second optical signal in response to determining, based on the comparison, that the acquired characteristics of the second blobs are suboptimal.

[0047] Some embodiments include at least one characteristic of the second optical signal that differs from at least one corresponding characteristic of the first optical signal, including a light intensity characteristic and / or a light duration characteristic. Some embodiments include image data corresponding to the second optical signal indicating a third blob for each of the passive markers of the first tracker generated from reflection by the passive marker of a second optical signal emitted from the light source, and distinguishing the second blob from the third blob based on the optimal characteristic in response to receiving the image data corresponding to the second optical signal. Some embodiments include distinguishing the second blob from the third blob based on the optimal characteristic by obtaining a characteristic of each third blob, comparing the obtained characteristics of the second and third blobs to the optimal characteristic, and distinguishing the second blob from the third blob based on the comparison of the obtained characteristics of the second and third blobs to the optimal characteristic.

[0048] Some embodiments include, for each of the second and third blobs, determining a difference between the acquired blob characteristic and the optimal characteristic, determining whether the difference is less than a threshold, and determining that the blob corresponds to one of the second blobs in response to determining that the difference is less than the threshold. Some embodiments include a predefined geometry of the passive marker of the first tracker and a predefined geometry of the passive marker of the second tracker that is substantially equivalent.

[0049] Some implementations include emitting light signals from a light source having varying characteristics; receiving image data generated by a localizer camera for each of the emitted light signals indicative of respective blobs of passive markers generated from reflection of the emitted light signals by the passive markers; obtaining, for each instance of the received image data, characteristics of each blob indicated by the image data and comparing the obtained characteristics to optimal characteristics to determine which of the instances of the received image data is closest to optimal; in response to determining which instance of the received image data is closest to optimal, assigning to a tracker the characteristics of the light signals corresponding to the instances of the received image data; and tracking a posture of the tracker within the surgical workspace based on the light signal characteristics assigned to the tracker.

[0050] Some implementations include tracking a posture of the tracker within a surgical workspace based on the light signal characteristics assigned to the tracker by emitting a light signal from a light source having the light signal characteristics assigned to the tracker to illuminate a passive marker of the tracker; receiving image data generated by a localizer camera corresponding to the emitted light signal having the light signal characteristics assigned to the tracker; and determining a posture of the tracker within the surgical workspace based on the received image data. Some implementations include emitting a light signal from a light source having light signal characteristics assigned to the tracker to illuminate passive markers of the tracker; receiving image data corresponding to the emitted light signal having the light signal characteristics assigned to the tracker, the received image data indicative of a blob of each passive marker of the tracker produced from reflection by the passive marker of the emitted light signal having the light signal characteristics assigned to the tracker; acquiring characteristics of each of the blobs in the received image data; comparing the acquired characteristics of the blobs in the received image data with optimal characteristics to determine if the acquired characteristics of the blobs are suboptimal; and adjusting the light signal characteristics assigned to the tracker in response to determining that the acquired characteristics of the blobs are suboptimal based on the comparison.

[0051] Some embodiments include determining positions of passive markers of the tracker within the surgical workspace based on the image data, and adjusting at least one optical parameter of the localizer camera based on the determined positions of the passive markers. Some embodiments include comparing the acquired characteristics of the blob to optimal characteristics to determine if the blob is suboptimal, and adjusting at least one optical parameter of the localizer camera based on the determined positions of the passive markers in response to determining the blob is suboptimal based on the comparison.

[0052] Some embodiments include adjusting at least one optical parameter of the localizer camera based on the determined position of the passive marker by determining an average distance between the passive marker and the localizer camera based on the determined position of the passive marker; comparing the determined average distance to a previously determined average distance between the passive marker and the localizer camera to determine a change in the average distance between the passive marker and the localizer camera; and adjusting at least one optical parameter of the localizer camera based on the change in the average distance. Some embodiments include adjusting at least one optical parameter of the localizer camera based on the change in average distance by determining whether the change in average distance indicates an increase or a decrease in the average distance between the passive marker and the localizer camera; increasing the intensity and / or duration of the optical signal emitted from the light source to illuminate the passive marker in response to the change in distance indicating an increase in the average distance between the passive marker and the localizer camera; and decreasing the intensity and / or duration of the optical signal emitted from the light source to illuminate the passive marker in response to the change in distance indicating a decrease in the average distance between the passive marker and the localizer camera.

[0053] Some embodiments include manually repositioning the passive marker of the tracker and determining and displaying guidance for repositioning the passive marker of the tracker based on a comparison of the acquired characteristics to an optimal characteristic. Some embodiments include, for each blob, assigning the blob to a passive marker corresponding to the blob, comparing the acquired characteristics of the blob to the optimal characteristic to determine whether the blob is suboptimal, and determining and displaying guidance for repositioning the passive marker corresponding to the blob based on the comparison and in response to determining that the blob is suboptimal.

[0054] Some embodiments include: determining and displaying guidance for relocating the passive marker corresponding to the blob away from the localizer camera 18 in response to a comparison indicating that the first value of the blob is greater than the second value; and determining and displaying guidance for relocating the passive marker corresponding to the blob toward the localizer camera 18 in response to a comparison indicating that the first value of the blob is less than the second value.

[0055] Some embodiments include adjusting at least one optical parameter of the localizer camera based on the comparison by adjusting an electronic aperture time of the localizer camera. Some embodiments include combining the obtained characteristics, where the optimal characteristic indicates a first value, to form a combined blob characteristic indicating a second value, comparing the second value to the first value, and, in response to the comparison indicating the second value being greater than the first value, decreasing the electronic aperture time of the localizer camera, and, in response to the comparison indicating the second value being less than the first value, increasing the electronic aperture time of the localizer camera.

[0056] Some embodiments include the localizer camera including a mechanical shutter, and adjusting at least one optical parameter of the localizer camera based on the comparison by adjusting a shutter time of the mechanical shutter. Some embodiments include the optimal characteristic exhibiting a first value, combining the obtained characteristics to form a combined blob characteristic exhibiting a second value, comparing the second value to the first value, and, in response to the comparison indicating the second value being greater than the first value, decreasing the shutter time of the mechanical shutter, and in response to the comparison indicating the second value being less than the first value, increasing the shutter time of the mechanical shutter.

[0057] Some embodiments include the localizer camera including a mechanical aperture, and adjusting at least one optical parameter of the localizer camera based on the comparison by adjusting a capture size of the mechanical aperture. Some embodiments include the optimal characteristic exhibiting a first value, combining the obtained characteristics to form a combined blob characteristic exhibiting a second value, comparing the second value to the first value, and, in response to the comparison indicating the second value being greater than the first value, decreasing the capture size of the mechanical aperture, and in response to the comparison indicating the second value being less than the first value. [Brief explanation of the drawings]

[0058] [Figure 1] 1 illustrates a surgical system including a surgical navigation system for optimizing tracking of a target within a surgical workspace. [Figure 2] Figure 1 shows components of the surgical system. [Figure 3] A method for optimizing the tracking of a target within a surgical workspace using an active tracker is presented. [Figure 4] 1 shows image data generated by a localizer camera of a surgical navigation system. [Figure 5] We show trackers that can be affixed to landmarks within the surgical workspace to track such landmarks. [Figure 6] 1 illustrates suboptimal image data generated by a localizer camera of a surgical navigation system. [Figure 7] 1 shows optimal image data generated by a localizer camera of a surgical navigation system. [Figure 8] A method for optimizing the tracking of targets within a surgical workspace using a passive tracker is presented. [Figure 9A] 1 shows an active tracker with a repositionable active marker oriented in a first direction. [Figure 9B]9B shows the active tracker of FIG. 9A with the repositionable active marker oriented in a second direction. [Figure 10A] 1 illustrates a passive tracker with a repositionable passive marker oriented in a first direction. [Figure 10B] 10B shows the passive tracker of FIG. 10A with the repositionable passive marker oriented in a second direction. DETAILED DESCRIPTION OF THE INVENTION

[0059] FIG. 1 illustrates a surgical system 10 for treating a patient. The surgical system 10 can be located in a surgical environment, such as an operating room in a medical facility. The surgical system 10 includes a surgical navigation system 12 and a robotic manipulator 14. The robotic manipulator 14 can be coupled to a surgical instrument 16 and configured to manipulate the surgical instrument 16 to treat a target volume of patient tissue, such as in the direction of the surgeon and / or the surgical navigation system 12. For example, the surgical navigation system 12 can cause the robotic manipulator 14 to manipulate the surgical instrument 16 to remove a target volume of patient tissue while avoiding other landmarks adjacent to the target volume within the surgical workspace, such as other medical instruments and adjacent anatomical structures. Alternatively, the surgeon can manually hold and manipulate the surgical instrument 16 while receiving guidance from the surgical navigation system 12. As some non-limiting examples, the surgical instrument 16 can be a burr instrument, an electrosurgical instrument, an ultrasonic instrument, a reamer, an impactor, or a sagittal saw.

[0060] During a surgical procedure, the surgical navigation system 12 is configured to track the pose (location and orientation) of targets of interest within a surgical workspace using tracker-based localization. The surgical workspace may include a target volume of patient tissue being treated and an area surrounding the target volume where obstacles to treatment may exist. Tracked targets may include, but are not limited to, the patient's anatomy, surgical instruments such as the surgical instrument 16, and the anatomy of surgical personnel, such as the surgeon's hands or fingers. The tracked patient anatomy may include soft tissues such as ligaments, muscles, and skin, and may include hard tissues such as bone. Tracked surgical instruments may include retractors, cutting tools, and waste management devices used during the surgical procedure.

[0061] Each landmark of interest may have a tracker affixed thereto that is configured to transmit optical signals to the surgical navigation system 12. The surgical navigation system 12 is configured to detect such optical signals by imaging the tracker and determine the pose of the tracker within the surgical workspace based on the imaging. The surgical navigation system 12 is then configured to determine the pose of the landmark within the surgical workspace based on the determined pose of the tracker and a predetermined positional relationship between the landmark and the tracker.

[0062] The surgical navigation system 12 may be configured to optimize tracking of targets within the surgical workspace, such as by optimizing the optical signal transmitted from the tracker to improve tracking accuracy. In particular, if the optical signal transmitted from the tracker is not optimal for the tracker's current position relative to the imaging device of the surgical navigation system 12 and / or for the current ambient lighting conditions, then the navigation system 12 may have difficulty accurately tracking the tracker within the surgical workspace. For example, if the optical signal strength is too low, then the navigation system 12 may detect an insufficient portion of the optical signal. Alternatively, if the optical signal strength is too high, then the navigation system 12 may produce undesirable artifacts when imaging the tracker. Either case may affect the surgical navigation system 12's ability to accurately indicate the location of the optical signal transmitted from the tracker, which may correspondingly affect the tracking accuracy provided by the surgical navigation system 12. Thus, in response to detecting an optical signal from a tracker, the navigation system 12 may be configured to compare the detected optical signal against optimal characteristics and adjust the optical signal transmitted from the tracker to obtain the optimal characteristics based on the comparison.

[0063] In response to determining the pose of the target landmark in the surgical workspace, the surgical navigation system 12 can display the relative pose of the tracked landmark to assist the surgeon. The surgical navigation system 12 can also control and / or constrain the movement of the robotic manipulator 14 and / or surgical instrument 16 based on virtual boundaries associated with the tracked landmarks. For example, the surgical navigation system 12 can identify the target volume of patient tissue to be treated and potential obstacles within the surgical workspace based on the tracked landmarks. The surgical navigation system 12 can then restrict the surgical instrument (e.g., the end effector EA of the surgical instrument 16) from contacting anything beyond the target volume of patient tissue to be treated, improving patient safety and surgical precision. The surgical navigation system 12 can also eliminate damage to the surgical instrument caused by unintended contact with other landmarks, which may also create unwanted debris at the target site.

[0064] 1 , the surgical navigation system 12 may include a localizer camera 18 and a navigation cart assembly 20. The navigation cart assembly 20 may house a navigation controller 22 configured to implement the functions, features, and processes of the surgical navigation system 12 described herein. In particular, the navigation controller 22 may include a processor 24 programmed to implement the functions, features, and processes of the navigation controller 22 and the surgical navigation system 12 described herein. For example, the processor 24 may be programmed to convert optical-based image data received from the localizer camera 18 into target pose data indicative of the pose of a target being tracked within the surgical workspace.

[0065] The navigation controller 22 can be in surgical communication with a user interface 26 of the surgical navigation system 12. The user interface 26 can facilitate user interaction with the surgical navigation system 12 and the navigation controller 22. For example, the user interface 26 can include one or more output devices that provide information to a user, such as from the navigation controller 22. The output devices can include a display 28 adapted to be located outside a sterile field that includes a surgical workspace and a display 30 adapted to be located inside the sterile field. The displays 28, 30 can be adjustably mounted to the navigation cart assembly 20. The user interface 26 can also include one or more input devices that enable user input to the surgical navigation system 12. The input devices can include a keyboard, mouse, and / or touch screen 32 that a user can interact with to input surgical parameters and control aspects of the navigation controller 22. The input devices can also include a microphone that enables user input via voice recognition technology.

[0066] The localizer camera 18 can be configured to facilitate identification of the pose of the tracked target within the surgical workspace by generating image data indicative of the pose of the tracker affixed to the target. Specifically, the localizer camera 18 can be communicatively coupled to the navigation controller 22 of the surgical navigation system 12 and configured to generate and communicate image data indicative of the pose of the tracker within the surgical workspace to the navigation controller 22. The navigation controller 22 can then be configured to generate target pose data indicative of the pose of the target affixed to the tracker within the surgical workspace based on the image data and a predetermined positional relationship between the target and the tracker.

[0067] The localizer camera 18 can be configured to facilitate identification of the pose of the tracked target within the surgical workspace by generating image data indicative of the pose of the tracker affixed to the target. Specifically, the localizer camera 18 can be communicatively coupled to the navigation controller 22 of the surgical navigation system 12 and configured to generate and communicate image data indicative of the pose of the tracker within the surgical workspace to the navigation controller 22. The navigation controller 22 can then be configured to generate target pose data indicative of the pose of the target affixed to the tracker within the surgical workspace based on the image data and a predetermined positional relationship between the target and the tracker.

[0068] The optical sensor 36 may be a one-dimensional or two-dimensional charge-coupled device (CCD). For example, the outer housing 34 may house two two-dimensional CCDs for triangulating the position of the tracker within the surgical workspace, or three primary source CCDs for triangulating the position of the tracker within the surgical workspace. Additionally or alternatively, the localizer camera 18 may utilize other light detection technologies, such as complementary metal-oxide semiconductor (CMOS) active pixels.

[0069] The localizer camera 18 may be mounted on an arm that is adjustable to selectively position the optical sensor 36 with a field of view of the surgical workspace and, ideally, a clear target volume. The localizer camera 18 may be adjustable in at least one degree of freedom by rotating about a rotary joint, and may be adjustable in two or more degrees of freedom.

[0070] As described above, the localizer camera 18, in cooperation with the multiple trackers 38, can determine the positions of landmarks within the surgical workspace to which the trackers 38 are affixed. Generally, the landmark to which each tracker 38 is affixed can be rigid and inflexible such that movement of the landmark cannot or is unlikely to alter the positional relationship between the landmark and the tracker 38. In other words, the relationship between the tracker 38 within the surgical workspace and the landmark to which the tracker 38 is affixed can remain fixed regardless of changes in the position of the landmark within the surgical workspace. For example, the trackers 38 may be firmly affixed to the patient's bones and surgical instruments, such as retractors and surgical instruments 16. In this manner, in response to determining the positions of the trackers 38 within the surgical workspace using the localizer cameras 18, the navigation controller 22 can infer the positions of the landmarks to which the trackers 38 are affixed based on the determined positions of the trackers.

[0071] For example, when the target volume to be treated is located in the patient's knee region, tracker 38A may be securely affixed to the patient's femur F, tracker 38B may be securely affixed to the patient's tibia T, and tracker 38C may be securely affixed to the surgical instrument 16. Trackers 38A, 38B may be attached to the femur F and tibia T as shown in U.S. Pat. No. 7,725,162, which is incorporated herein by reference. Trackers 38A, 38B may also be attached like the trackers shown in U.S. Pat. No. 9,566,120, which is incorporated herein by reference. Tracker 38C may be integrated into the surgical instrument 16 during manufacture or may be separately attached to the surgical instrument 16 in preparation for the surgical procedure.

[0072] Prior to the commencement of a surgical procedure using the surgical system 10, preoperative images can be generated for the anatomical structure of interest, such as defining a target volume of patient tissue to be treated by the surgical instrument 16 and / or adjacent anatomical structures. For example, when the target volume of patient tissue to be treated is within the patient's knee region, preoperative images can be taken of the patient's femur F and tibia T. These images can be based on MRI, radiological, or computed tomography (CT) scans of the patient's anatomy and can be used to create virtual models of the anatomy. Each virtual model of the anatomy can include data representing all or at least a portion of the anatomy and / or a three-dimensional model (e.g., point cloud, mesh CAD) including data indicative of the portion of the anatomy to be treated. These virtual models can be provided to and stored in the navigation controller 22 prior to the surgical procedure.

[0073] In addition to, or instead of, taking preoperative images, treatment plans can be developed in the operating room from kinematic studies, bone tracking, and other methods. These same methods may also be used to generate the virtual models described above.

[0074] In addition to the virtual model corresponding to the patient's target anatomical structures, prior to a surgical procedure, the navigation controller 22 can receive and store virtual models for other tracked landmarks, such as surgical instruments and other landmarks (e.g., the surgeon's hands and / or fingers) potentially present within the surgical workspace. The navigation controller 22 can also receive and store a virtual model of each tracker 38 positioned within the surgical workspace and the positional relationship between each tracker 38 and the landmark to which the tracker 38 is attached. For example, each positional relationship between a tracker 38 and the landmark to which the tracker 38 is attached may be represented in the navigation controller 22 by a relational model that links the virtual model of the tracker 38 and the virtual model of the landmark in a common three-dimensional coordinate system. In this manner, in response to identifying the pose of a tracker 38 within the surgical workspace, the navigation controller 22 can reference the relational model of the tracker 38 to determine the pose of the landmark to which the tracker 38 is attached within the surgical workspace.

[0075] In some examples, the positional relationship between each tracker 38 and the target to which the tracker 38 is affixed can be manually indicated via the user interface 26. Alternatively, the positional relationship between each tracker 38 and the target to which the tracker 38 is affixed can be determined by tracking the target with a pointer instrument having its own fixed tracker 38 that is tracked by the navigation system 12 during tracking, with the navigation system 12 also simultaneously tracking the tracker 38 affixed to the target to correlate the pose of the tracked target to the pose of the affixed tracker 38.

[0076] The navigation controller 22 can also receive and store surgical planning data prior to the procedure. The surgical planning data can identify the patient's anatomical structures involved in the surgical procedure, can identify the instruments being used in the surgical procedure, and can define the planned trajectories of the instruments and the planned movements of the patient's tissues during the surgical procedure.

[0077] During a surgical procedure, the optical sensor 36 of the localizer camera 18 can detect optical signals, such as non-visible optical signals (e.g., infrared or ultraviolet) emitted by the tracker 38, and can output optically-based signals indicative of the image plane location of the image where the optical sensor 36 detected the optical signal. The localizer camera 18 can be configured to integrate these signals into image data that is then communicated to the navigation controller 22. Based on the image data and a predetermined positional relationship between the tracker 38 and the target, the navigation controller 22 can be configured to generate target pose data indicative of the position of the target to which the tracker 38 is affixed in a common coordinate system, such as a coordinate system specific to the localizer camera 18.

[0078] The surgical instrument 16 can form part of an end effector of the robotic manipulator 14. The robotic manipulator 14 can include a base 40, several links 42 extending from the base 40, and several active joints 44 for moving the surgical instrument 16 relative to the base 40. The links 42 can form a series arm structure as shown in FIG. 1, a parallel arm structure, or any other suitable structure. The robotic manipulator 14 can include the capability to operate in a manual mode in which a user grasps the end effector of the robotic manipulator 14 and causes movement of the surgical instrument 16 (e.g., directly or via force / torque sensor measurements that cause active actuation of the robotic manipulator 14). The robotic manipulator 14 can also include a semi-autonomous mode in which the surgical instrument 16 is moved along a predefined tool path by the robotic manipulator 14 (e.g., the active joints 44 of the robotic manipulator 14 are manipulated to move the surgical instrument 16 without requiring force / torque on the end effector from the user). An example of operation in a semi-autonomous mode is also described in U.S. Patent No. 9,119,655 to Bowling, et al., which is incorporated herein by reference. A separate tracker 38 can also be attached to the base 40 of the robotic manipulator 14 to track the movement of the base 40 with the localizer camera 18.

[0079] Similar to the surgical navigation system 12, the robotic manipulator 14 can contain a manipulator controller 46 that includes a processor 48 programmed to implement the functions, features, and processes of the robotic manipulator 14, or more particularly, of the manipulator controller 46 described herein. For example, the processor 48 can be programmed to control the movement and movement of the surgical instrument 16, such as in the direction of the surgical navigation system 12, through movement of the link 42.

[0080] During a surgical procedure, the manipulator controller 46 can be configured to determine a desired location to which the surgical instrument 16 should be moved, such as based on navigation data received from the navigation controller 22. Based on this determination and information regarding the current position of the surgical instrument 16, the manipulator controller 46 can be configured to determine an extent to which the links 42 need to be moved to reposition the surgical instrument 16 from its current position to a desired position. Data indicating where the links 42 should be repositioned can be transferred to joint motor controllers (e.g., for controlling the respective motors) that control the active joints 44 of the robotic manipulator 14. In response to receiving such data, the joint motor controllers can be configured to move the links 42 in accordance with the data, thereby moving the surgical instrument 16 to the desired position.

[0081] 2, the localizer camera 18 may include a localizer controller 52 communicatively coupled to the optical sensor 36 and to the navigation controller 22. During a surgical procedure, the localizer controller 52 may be configured to operate the optical sensor 36 to cause the optical sensor 36 to generate optically-based signals indicative of detected optical signals received from the tracker 38, or more specifically, indicative of the image plane positions of the optical sensor 36 where such optical signals were detected.

[0082] The tracker 38 may each include a predefined geometry of markers 54 that directs an optical signal toward the optical sensor 36. In some implementations, the tracker 38 may be an active tracker 38 having at least three active markers 54, each of which receives electrical current from a power source to generate an optical signal that is emitted toward the optical sensor 36. In this case, the trackers 38 may each be powered by an internal battery or may have leads for receiving power through the navigation controller 22. For example, the active markers 54 may be light-emitting diodes (LEDs) that transmit light, such as non-visible light (e.g., infrared or ultraviolet light), toward the optical sensor 36.

[0083] Each active tracker 38 may also include a tracker controller 56 communicatively coupled to the active markers 54 and to the navigation controller 22. The tracker controller 56 may be configured to control the rate and sequence in which the active markers 54 fire, such as in the direction of the navigation controller 22. For example, the tracker controller 56 of a tracker 38 may cause the active markers 54 of each tracker 38 to fire at different rates and / or times to facilitate differentiation of the trackers 38 and / or markers 54 by the navigation controller 22. In some examples, the navigation controller 22 can form a bidirectional infrared communication channel with each tracker controller 56 to control the timing of the firing of the active markers 54, write / read non-volatile data, and obtain the status (e.g., battery level, broken LED) of the active tracker 38 or the object to which the active tracker 38 is affixed.

[0084] The sampling rate of the optical sensor 36 is the rate at which the optical sensor 36 detects optical signals from successively emitted markers 54. The optical sensor 36 may have a sampling rate of 100 Hz or greater, or more preferably 300 Hz or greater, or most preferably 500 Hz or greater. In one example, the optical sensor 36 may have a sampling rate of 8000 Hz.

[0085] Rather than being active, the tracker 38 may be a passive tracker 38 that includes passive markers 54, such as reflectors that reflect light emitted from the localizer camera 18. Specifically, the localizer camera 18 may include a light source 58 that illuminates the tracker 38 with light, such as non-visible light (e.g., infrared or ultraviolet). The markers 54 may be configured to reflect light back toward the localizer camera 18, which can then be detected by the optical sensor 36. In some examples, a surgical workspace may include a combination of active and passive trackers 38 to track various objects within the surgical workspace.

[0086] In response to optical sensors 36 receiving optical signals from trackers 38, optical sensors 36 can output optical-based signals to localizer controller 52 that indicate the orientation of tracker 38 relative to localizer camera 18, and correspondingly, the orientation of targets affixed to tracker 38 relative to localizer camera 18. In particular, each optical sensor 36 can include a one- or two-dimensional sensor area (also referred to as an “image plane”) that detects optical signals from tracker 38 and, in response, outputs optical-based signals that indicate pixel coordinates within the sensor area at which each optical signal was detected. Thus, the optical-based signals output from each optical sensor 36 can represent an image of tracker 38 generated by optical sensor 36 from the detected optical signals, the image including blobs within pixel coordinates that correspond to locations within the image plane of optical sensor 36 at which the optical signals were detected. The detected location of each optical signal can be based on the angle at which the optical signal was received by optical sensor 36 and, therefore, can correspond to the location of a marker 54 within the surgical workspace that emitted the detected optical signal toward optical sensor 36.

[0087] The optical sensors 36 can communicate optical-based signals to the localizer controller 52, which can similarly generate image data for each optical sensor 36 based on the optical-based signals received from the optical sensors 36 and present such image data to the navigation controller 22. The image data for the optical sensors 36 can indicate the image and / or image plane position represented by the optical-based signals received from the optical sensors 36. The navigation controller 22 can then generate tracker attitude data indicating the attitude of the tracker 38 relative to the localizer camera 18 based on the received image data. More specifically, the navigation controller 22 can determine the position of the tracker 38 in the coordinate system of the localizer camera 18 based on the image data. For example, the navigation controller 22 can be configured to correlate blobs corresponding to the same marker 54 in image data generated simultaneously for each optical sensor 36, triangulate the positions of the markers 54 relative to the localizer camera 18 based on the positions of the correlated blobs in the image data and predetermined positional relationships between the optical sensors 36, and assign the triangulated positions to the predefined geometry of the markers 54 of each tracker 38 to determine the attitude of each tracker 38 relative to the localizer camera 18.

[0088] Thereafter, navigation controller 22 can generate target attitude data based on the tracker attitude data, the target attitude data indicating the attitude of the target affixed to tracker 38 relative to localizer camera 18. Specifically, navigation controller 22 can retrieve stored positional relationships between tracker 38 and the target to which tracker 38 is affixed and apply these positional relationships to the tracker attitude data to determine the attitude of the target fixed to tracker 38 relative to localizer camera 18. Alternatively, localizer controller 52 can be configured to determine the tracker attitude data and / or target attitude data based on optical-based signals generated by optical sensor 36 and transmit the tracker attitude data and / or target attitude data to navigation controller 22 for further processing.

[0089] As mentioned above, the navigation controller 22 may include a processor 24 programmed to execute the functions, features, and processes of the navigation controller 22 described herein. The navigation controller 22 may also include a memory 60 and a non-volatile storage device 62, each operatively coupled to the processor 24.

[0090] Processor 24 may include one or more devices selected from a microprocessor, microcontroller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuit, analog circuit, digital circuit, or any other device that manipulates signals (analog or digital) based on operational instructions stored in memory 60. Memory 60 may include a single memory device or multiple memory devices, including, but not limited to, read-only memory (ROM), random access memory (RAM), volatile memory, nonvolatile memory, static random access memory (SRAM), dynamic random access memory (DRAM), flash memory, cache memory, or any other device capable of storing information. Non-volatile storage device 62 may include one or more persistent data storage devices, such as a hard drive, optical drive, tape drive, non-volatile solid-state device, or any other device capable of persistently storing information.

[0091] The non-volatile storage 62 can store software 64, which may include one or more applications and / or modules, such as a localization engine 66, a surgical navigator 68, and an optimizer 70. Each application or module can be embodied by a separate set of computer-executable instructions compiled or interpreted from various programming languages ​​and / or technologies, including, but not limited to, Java, C, C++, C#, Objective C, Fortran, Pascal, Java Script, Python, Perl, and PL / SQL, either alone or in combination. The processor 24 can operate under the control of the software 64 stored in the non-volatile storage 62. In particular, the processor 24 can be configured to load into the memory 60 and execute the computer-executable instructions that embody the software 64. When executed by the processor 24, the computer-executable instructions can be configured to cause the processor 24 to implement the configured functions, features, and processes of the navigation controller 22 described herein.

[0092] The non-volatile storage 62 of the navigation controller 22 may also store data 74 that facilitates operation of the navigation controller 22. In particular, the software 64 of the navigation controller 22 may be configured to access the data 74, when executed, to facilitate implementation of the functions, features, and processes of the navigation controller 22 described herein. For example, the data 74 stored in the non-volatile storage 62 may include model data 76, surgical planning data 78, and optimal blob data 80.

[0093] The model data 76 may include virtual models of anatomical structures important to the surgical procedure, including virtual models of potential obstacles such as the surgeon's hands or fingers, as described above, and virtual models of surgical instruments being used in the surgical procedure. The model data 76 may also include a virtual model of each tracker 38, indicating the predetermined geometry of the markers 54 of the trackers 38 and the positional relationship between each tracker 38 and the target object to which the tracker 38 is affixed. The model data 76 may also indicate configuration parameters of the localizer camera 18, such as the position of the optical sensor 36 within a coordinate system specific to the localizer camera 18, to enable triangulation of the positions of the markers 54 within the coordinate system specific to the localizer camera 18 based on image data generated by the localizer camera 18.

[0094] The surgical planning data 78 may identify the patient's anatomical structures and target volumes involved in the surgical procedure, may identify the instruments being used in the surgical procedure, and may define the planned trajectories of the instruments and the planned movements of the patient's tissues during the surgical procedure. The optimal blob data 80 may indicate optimal characteristics of a blob generated by the localizer camera 18 from the optical signals received from the markers 54 of the tracker 38 to optimize the received optical signals and improve tracking accuracy.

[0095] Referring again to software 64 executable by processor 24 of navigation controller 22, localization engine 66 can be configured to generate tracker pose data indicating the pose of tracker 38 relative to localizer camera 18, such as based on image data received from localizer camera 18. Localization engine 66 can also be configured to convert the pose of tracker 38 relative to localizer camera 18 to the pose of a target attached to tracker 38 relative to localizer camera 18, such as based on the tracker pose data and positional relationships indicated in model data 76.

[0096] The surgical navigator 68 can be configured to provide surgical guidance based on the target pose data and the surgical planning data 78. For example, the surgical navigator 68 can be configured to display the relative poses of the tracked targets on the navigation displays 28, 30 and issue control commands to the robotic manipulator 14 to move the surgical instrument 16 while avoiding undesired contact with other tracked targets.

[0097] Optimizer 70 can be configured to optimize tracking of targets within the surgical workspace by adjusting optical signals transmitted by markers 54 of tracker 38 to localizer camera 18, for example, based on a comparison of image data generated by localizer camera 18 with optimal blob data 80. Examples of such optimization are described in more detail below.

[0098] Each of the manipulator controller 46 and the localizer controller 52 may also include a processor, memory, and non-volatile storage containing data and software configured, when executed by the processor, to implement the functions, features, and processes of the controller described herein.

[0099] 3 illustrates a method 100 for optimizing tracking of a target within a surgical workspace by adjusting an optical signal emitted from a tracker 38 to improve tracking accuracy. Method 100 can be utilized when an active tracker 38 including an active marker 54 is present within the surgical workspace. Method 100 can be facilitated by surgical navigation system 12, or more particularly, by navigation controller 22, such as during execution of software 64.

[0100] At block 102, the trackers 38 can be positioned relative to landmarks within the surgical workspace that are desired to be tracked. In particular, a tracker 38 can be affixed to each landmark, with each tracker 38 including an active marker 54 of predefined geometry. The positional relationship between each tracker 38, or more specifically, the marker 54 of each tracker 38, and the landmark to which the tracker 38 is affixed, can be stored as model data 76 in the non-volatile storage 62 of the navigation controller 22.

[0101] At block 104, image data can be generated by the localizer camera 18, such as in the direction of the navigation controller 22. In particular, the navigation controller 22 can communicate control signals to the tracker controller 56 of the tracker 38 that instruct the tracker controller 56 to emit optical signals, such as non-visible optical signals, from the active markers 54. Simultaneously, the navigation controller 22 can communicate control signals to the localizer controller 52 that instruct the localizer controller 52 to operate the optical sensors 36 to detect the optical signals emitted from the active markers 54. Each of the optical sensors 36 can responsively generate an optical-based signal indicative of a blob for each active marker 54, the blob having pixel coordinates corresponding to the location in the image plane of the optical sensor 36 at which the optical signal was received from the active marker 54. The localizer controller 52 can receive the optical-based signals from the optical sensors 36 and communicate image data corresponding to the optical-based signals to the navigation controller 22, as described above.

[0102] FIG. 4 shows image data 120 that can be generated for the two-dimensional optical sensor 36 of the localizer camera 18 from optical signals emitted by the active markers 54 of the exemplary tracker 38 shown in FIG. 5. As shown in the depicted example, the image data 120 can show a two-dimensional image 122 that includes blobs 124. Each of the blobs 124 can be generated from optical signals emitted from a different one of the active markers 54 of the tracker 38 shown in FIG. 5, and the pixel coordinates of each blob 124 in the image 122 correspond to the location on the image plane of the optical sensor 36 where the optical signal corresponding to the blob 124 was detected. For example, blob 124 can be generated from optical signals emitted from active marker 54A, blob 124B can be generated from optical signals emitted from active marker 54B, and so on.

[0103] 3 , at block 106, each blob 124 of image data generated by localizer camera 18 may be assigned to an active marker 54 of tracker 38 corresponding to blob 124, such as by navigation controller 22 during execution of localization engine 66. For example, tracker controller 56 of tracker 38 may be configured to emit active markers 54 at different times and / or speeds, such as in the direction of navigation controller 22, and localizer camera 18 may be configured to generate different image data for each emitted active marker 54. Thus, navigation controller 22 may correlate the blob 124 of each instance of received image data with the active marker 54 that was emitted when the image data was generated.

[0104] As a further example, for example, if active markers 54 are fired simultaneously, navigation controller 22 can be configured to correlate blobs 124 corresponding to the same marker 54 in simultaneously generated image data for optical sensors 36, such as by applying epipolar geometry to the image data, based on a predetermined positional relationship between optical sensors 36, which can be stored as model data 76 in non-volatile storage 62 of navigation controller 22. Navigation controller 22 can then be configured to triangulate the three-dimensional position of each group of correlated blobs 124 relative to localizer camera 18. Navigation controller 22 can then be configured to apply model data 76, indicating a predetermined geometry of markers 54 of each tracker 38, to the triangulated positions to identify triangulated positions corresponding to each marker 54 of each tracker 38 and assign blobs accordingly.

[0105] For example, assuming a tracker 38 having markers 54 of six predefined geometries is present within the surgical workspace, the navigation controller 22 can be configured to identify each possible combination of six triangulated positions. For each possible combination, the navigation controller 22 can then determine whether the geometry formed by the triangulated positions of the combination matches the predefined geometry of the markers 54 of the tracker 38. If there is a match, the navigation controller 22 can then be configured to assign each blob used to generate the triangulated positions of the combination to the marker 54 of the tracker 38 that generated the blob, such as by matching a relationship between the triangulated position corresponding to the blob and the other triangulated positions of the combination to one of the markers 54 of the predefined geometries.

[0106] As described above, in response to assigning a blob to the marker 54 of the tracker 38 that generated the blob, the navigation controller 22 can be configured to determine the pose of the target object to which the tracker 38 is attached. In particular, if not already calculated, the navigation controller 22 can be configured to triangulate the position of each marker 54 of the tracker 38 relative to the localizer camera 18 based on the positions of the blobs assigned to the markers 54 in the image data and the predetermined positional relationship between the optical sensors 36. The positions of the markers 54 relative to the localizer camera 18 indicate the pose of the tracker 38 relative to the localizer camera 18, and the navigation controller 22 can then be configured to determine the pose of the target object to which the tracker 38 is attached relative to the localizer camera 18 based on the triangulated positions of the markers 54 and the predetermined positional relationship between the tracker 38 and the target object, as described above.

[0107] The following blocks of method 100 may involve optimizing the optical signals emitted from the active markers 54 to improve tracking accuracy. In particular, emitting suboptimal optical signals from the active markers 54 may result in the optical sensors 36 generating suboptimal blobs, which may in turn lead to suboptimal or inaccurate tracking. For example, if the intensity of the optical signals emitted from the active markers 54 is too low for the current lighting conditions and the current distance between the active markers 54 and the localizer cameras 18, then the localizer cameras 18 may not properly detect the optical signals for purposes of tracking the active markers 54. Alternatively, if the intensity of the optical signals emitted from the active markers 54 is too high, then the optical signals may oversaturate one or more pixels in the image plane of each optical sensor 36, which may cause undesirable artifacts in the image data that affect the ability of the navigation controller 22 to accurately track the active markers 54.

[0108] As an example, FIG. 6 shows exemplary image data 132 that may be generated by the optical sensor 36 from optical signals emitted from an active marker 54 that cause oversaturation of one or more pixels of the optical sensor 36. As shown in the illustrated example, the image data 132 may include undesirable artifacts caused by oversaturation, such as blooming artifacts 134 and smearing artifacts 136. Such artifacts may cause the navigation controller 22 to inaccurately calculate the three-dimensional position of the active marker 54 relative to the localizer camera 18, which in turn may lead to inaccurate tracking of the target object to which the active marker 54 corresponds. Conversely, FIG. 7 shows exemplary image data 138 that may be generated by the optical sensor 36 from an optimal optical signal emitted from the active marker 54. As shown in the illustrated example, the image data 138 may show a blob 124N generated from an optical signal that is circular and uniform in intensity.

[0109] Referring again to FIG. 3 , at block 108, one of the blobs 124 in the image data can be selected, and at block 110, one or more characteristics of the selected blob 124 can be obtained. For example, the navigation controller 22 can identify an intensity characteristic, a size characteristic, and / or a shape characteristic of the selected blob 124, such as via the optimizer 70. The intensity characteristic can correspond to the magnitude of the optical signal received by the optical sensor 36 corresponding to the selected blob 124 and can be determined as the highest pixel intensity of the blob 124, the average pixel intensity of the blob 124, or the first moment of the blob 124. The size characteristic can correspond to the area of ​​the blob 124 and can be determined by counting the number of pixels that form the blob 124. The shape characteristic of the selected blob 124 can correspond to the perimeter of the selected blob 124 and can be determined using an edge detection algorithm.

[0110] At block 112, the acquired characteristics can be compared to corresponding optimal characteristics, and at block 114, a determination can be made based on the comparison whether the blob is optimal. More particularly, the non-volatile storage 62 of the navigation controller 22 can store optimal blob data 80 indicating one or more optimal blob characteristics. The optimal blob characteristics indicated by the optimal blob data 80 can correspond to characteristics of the blob that enable the surgical navigation system 12 to accurately locate the marker 54 that generated the blob, and therefore can be compared to the acquired characteristics to determine whether the blob is optimal for navigation purposes. For example, the optimal blob data 80 can indicate optimal intensity characteristics for comparison with the acquired intensity characteristics, optimal size characteristics for comparison with the acquired size characteristics, and / or optimal shape characteristics for comparison with the acquired shape characteristics.

[0111] Each optimal blob characteristic may indicate an optimal value or range of optimal values ​​for which the corresponding acquired blob characteristic may be considered optimal. For example and without limitation, an optimal intensity characteristic may indicate a single intensity value that is greater than or equal to 75% and less than or equal to 95% of the full intensity value of a pixel of the optical sensor 36, such as 80%, 85%, or 90%. The full intensity value of a pixel of the optical sensor 36 may correspond to the maximum light intensity that a given pixel can accommodate before becoming oversaturated. If the acquired intensity characteristic is greater than or less than the indicated optimal intensity value, the acquired intensity characteristic may not be considered optimal.

[0112] Alternatively, the optimal intensity characteristic may indicate a range of optimal values ​​defined by a low intensity threshold, such as 75% of the full intensity value of a pixel of the optical sensor 36, and a high intensity threshold, such as 95% of the full intensity value of a pixel of the optical sensor 36. In this case, the acquired intensity characteristic may be considered optimal if it is greater than or equal to the lower intensity threshold and less than or equal to the higher intensity threshold. As alternative, non-limiting examples, the optimal intensity characteristic may indicate a range of 60%-95%, 80%-95%, or 85%-95% of the full intensity value of a pixel of the optical sensor 36. The optimal size characteristic may similarly indicate an area value or range of area values ​​for which the acquired characteristic may be considered optimal.

[0113] The optimal shape characteristic may indicate an optimal shape (e.g., circular) with an optimal area, and may indicate an optimal ratio value (e.g., 1) or a range of optimal ratio values ​​defined by a lower ratio threshold (e.g., 0.8) and a higher ratio threshold (e.g., 1.2). To compare the acquired shape characteristic of a given blob to the optimal shape characteristic, the navigation controller 22 may be configured to align the shape of the acquired blob with the optimal shape of the optimal shape characteristic and calculate the ratio of the area of ​​the acquired shape that extends outside the optimal shape to the area of ​​the optimal shape that extends outside the acquired shape. This calculated ratio may be considered to at least partially define the acquired shape characteristic of the given blob. If the optimal shape characteristic indicates a single optimal ratio value, then the acquired shape characteristic may be considered optimal if the calculated ratio is equal to the optimal ratio value. Alternatively, if the optimal shape characteristic indicates a range of optimal ratio values, then the acquired shape characteristic may be considered optimal if the calculated ratio is greater than or equal to the low ratio threshold and less than or equal to the high ratio threshold.

[0114] In response to determining that the obtained blob characteristics are not optimal (the "No" branch of block 114), in block 116, the light signals emitted from the active marker 54 corresponding to the blob 124 can be adjusted for future tracking of the marker 54, such as to cause the active marker 54 to emit light signals that lead to the production of optimal or near-optimal blob characteristics for future tracking. More particularly, the intensity and / or duration of the light signals emitted from the active marker 54 can be adjusted. For example, the navigation controller 22 can be configured to communicate a control signal to the tracker controller 56 for the active marker 54, such as via the optimizer 70, that causes the tracker controller 56 to adjust the intensity and / or duration of the light signals emitted from the active marker 54 for future tracking of the marker 54. More specifically, if the acquired blob characteristics are greater than one or more optimal values ​​defined by the corresponding optimal blob characteristics, then navigation controller 22 can be configured to communicate a control signal to tracker controller 56 that causes tracker controller 56 to reduce the intensity and / or duration of the optical signal emitted from active marker 54. Alternatively, if the acquired blob characteristics are less than one or more optimal values ​​defined by the corresponding optimal blob characteristics, then navigation controller 22 can be configured to communicate a control signal to tracker controller 56 that causes tracker controller 56 to increase the intensity and / or duration of the optical signal emitted from active marker 54.

[0115] The intensity of the optical signal emitted from the active marker 54 may be proportional to the magnitude of the current applied to the active marker 54. Thus, if the intensity of the optical signal emitted from the active marker 54 should be increased, then a control signal communicated to the tracker controller 56 can cause the tracker controller 56 to increase the current applied to the active marker 54 in future tracking iterations. Conversely, if the intensity of the optical signal emitted from the active marker 54 should be decreased, then a control signal communicated to the tracker controller 56 can cause the tracker controller 56 to decrease the current applied to the active marker 54 in future tracking iterations. The duration of the optical signal emitted from the active marker 54 may be proportional to the duration that the current is applied to the active marker 54, which can likewise be adjusted to produce shorter or longer durations.

[0116] The extent to which the intensity and / or duration of the emitted light signal is increased or decreased may be proportional to the difference between the acquired characteristic and the optimal characteristic. Additionally or alternatively, the navigation controller 22 may be configured to implement a PID loop and / or a stored lookup table to determine the extent to which the intensity and / or duration of the emitted light signal is increased or decreased to optimize the acquired blob characteristic.

[0117] In some examples, the navigation controller 22 can be configured to optimize a particular type of acquired blob characteristic over other types. For example, for a given blob 124, the navigation controller 22 can be configured to first optimize the acquired intensity characteristic of the blob 124. In response to optimizing the acquired intensity characteristic, the navigation controller 22 can then be configured to optimize the acquired size characteristic. In response to optimizing the acquired size characteristic, the navigation controller 22 can then be configured to optimize the acquired shape characteristic. Thus, during each tracking and optimization iteration, the navigation controller 22 can be configured to acquire and check whether the highest priority blob characteristic type is optimal. If not, then the navigation controller 22 can be configured to adjust the light signal emitted from the corresponding active marker 54 to optimize the blob characteristic type for future iterations, as described above. If the highest priority blob characteristic type is determined to be optimal, then the navigation controller 22 can be configured to acquire and check whether the next highest priority blob characteristic type is optimal, and so on.

[0118] In response to determining that the acquired blob characteristics are optimal (the “Yes” branch of block 114) or adjusting the optical signal emitted from the corresponding active marker 54 in block 116, a determination may be made in block 118 as to whether the image data includes additional blobs 124 that have not yet been matched to the optimal blob characteristics. If so (the “Yes” branch of block 118), then the method 100 may return to block 108 to select additional blobs 124 and repeat blocks 110 through 116, as appropriate. If not (the “No” branch of block 118), then the method 100 may return to block 104 to generate further image data of the tracker 38 within the surgical workspace, and so on. Thus, the optical signal emitted from a given marker 54 may change over time and may be adjusted multiple times throughout a given surgical procedure.

[0119] In some examples, the navigation controller 22 can be configured to jointly optimize blobs 124 in the image data that correspond to the same active marker 54, rather than optimizing each blob 124 separately. As described above, the image data generated by the localizer camera 18 can include image data for each optical sensor 36, with each instance of the image data indicating that a blob for each active marker 54 in the surgical workspace emits an optical signal when the image data is captured. For each set of blobs in the image data that correspond to the same active marker 54, which can be determined as described above, the navigation controller 22 can be configured to acquire at least one characteristic of each blob. The navigation controller 22 can then be configured to combine acquired characteristics of the same type (e.g., intensity, size, shape) to form a combined blob characteristic of the type for the set of blobs, such as by averaging values ​​indicated by the acquired characteristics of the type. For example, the navigation controller 22 may be configured to determine a combined blob intensity characteristic of the set of corresponding blobs 124 by averaging the intensity values ​​of the acquired intensity characteristics of the corresponding blobs 124, to determine a combined blob size characteristic of the set of corresponding blobs 124 by averaging the areas indicated by the acquired size characteristics of the corresponding blobs 124, and to determine a combined blob shape characteristic of the set of corresponding blobs 124 by averaging the ratios indicated by the acquired shape characteristics of the corresponding blobs 124.

[0120] Navigation controller 22 can then be configured to compare each combined blob characteristic to a corresponding optimal blob characteristic to determine whether the combined blob characteristic is not optimal. If not, navigation controller 22 can then be configured to communicate a control signal to tracker 38 that includes active marker 54 that corresponds to the combined blob characteristic, causing tracker 38 to adjust the light signal emitted from active marker 54, as described above.

[0121] To this end, navigation controller 22 can also be configured to prioritize optimizing a particular type of combined blob characteristic, as described above. For example, for a set of blobs 124 corresponding to the same active marker 54, navigation controller 22 can be configured to first determine the combined blob characteristic of the highest priority type (e.g., blob intensity) and compare the combined blob characteristic with the corresponding optimal characteristic to determine whether the combined blob characteristic is not optimal. In response to determining, based on the comparison, that the highest priority combined blob characteristic is not optimal, navigation controller 22 can be configured to communicate a control signal to tracker 38 that causes tracker 38 to adjust the light signal emitted from active marker 54 corresponding to the combined blob characteristic, as described above.

[0122] Conversely, in response to determining, based on the comparison, that the combined blob characteristic is best, navigation controller 22 can be configured to obtain a characteristic of each blob in the set that is of the next highest priority type (e.g., size, shape), combine these obtained characteristics to form a further combined blob characteristic of the next highest priority type, and compare the further combined blob characteristic with the optimal characteristic corresponding to the next highest priority type to determine whether the further combined blob characteristic is not best. In response to determining, based on the comparison, that the further combined blob characteristic is not best, navigation controller 22 can be configured to communicate a control signal to tracker 38 that causes tracker 38 to adjust the light signal emitted from active marker 54 corresponding to the corresponding blob 124, as described above.

[0123] In some alternative examples, the navigation controller 22 can be configured to optimize the light signal emitted from each active marker 54 based on blob characteristics obtained from only one of the blobs 124 corresponding to the active marker 54, such as the blob 124 shown in image data generated by a designated one of the optical sensors 36.

[0124] In some examples, different trackers 38 may be optimized for different optimal blob characteristics. To this end, optimal blob data 80 may indicate different sets of one or more optimal blob characteristics for different trackers 38. For example, optimal blob data 80 may indicate optimal intensity characteristics of 90% of the full intensity value of a pixel of optical sensor 36 for one tracker 38, optimal intensity characteristics of 80% of the full intensity value of a pixel of optical sensor 36 for another tracker 38, and so on.

[0125] Under this configuration, in response to receiving image data indicating blobs 124 corresponding to the active markers 54 of one or more trackers 38, the navigation controller 22 can be configured to assign the blob 124 to the active marker 54 of each tracker 38 based on one or more optimal characteristics specific to the tracker 38. More specifically, to determine whether a blob 124 corresponds to a given tracker 38, the navigation controller 22 can be configured to determine a difference between the obtained characteristics of the blob 124 and the corresponding optimal characteristic specific to the tracker 38 and determine whether the difference is less than a threshold value (e.g., 5% of the corresponding optimal characteristic). If less than the threshold value, then the navigation controller 22 can be configured to determine that the blob 124 corresponds to the tracker 38 and assign the blob 124 to the active marker 54 of the tracker 38 that corresponds to the blob 124, such as based on a predefined geometry of the marker 54 of the tracker 38, as described above.

[0126] In some examples, such as when multiple types of characteristics are obtained for each blob 124, the navigation controller 22 can be configured to determine whether a blob 124 corresponds to a given tracker 38 by determining whether each difference between the obtained characteristic of the blob 124 and the corresponding optimal characteristic specific to the tracker 38 is less than a threshold value (e.g., 5% of the corresponding optimal characteristic) determined based on the corresponding optimal characteristic. Alternatively, the navigation controller 22 can be configured to determine the average or sum of squared differences between the obtained characteristic of the blob 124 and the corresponding optimal characteristic specific to the tracker 38 and determine whether such value is less than the threshold value. If so, then the navigation controller 22 can be configured to determine that the blob 124 corresponds to the tracker 38 and assign the blob 124 to the active marker 54 of the tracker 38 corresponding to the blob 124, as described above.

[0127] In some examples, the navigation controller 22 may be configured to determine one or more combined blob characteristics for a given set of blobs 124 identified as corresponding to the same active marker 54, as described above, and compare the combined blob characteristics to the corresponding best-fit characteristics described in the paragraph above to determine whether the set of blobs 124 corresponds to a given tracker 38. If so, the navigation controller 22 may then be configured to determine that the set of blobs 124 corresponds to the tracker 38 and assign the set of blobs 124 to the active markers 54 of the tracker 38 that correspond to the blobs 124, such as based on a predefined geometry of the markers 54 of the tracker 38, as described above.

[0128] When the trackers 38 are optimized for different optimal characteristics, multiple trackers 38 having substantially identical predetermined geometries of their markers 54 may be present within the surgical workspace. In other words, assuming the same pose and the same illumination characteristics within the surgical workspace, the predetermined geometries of the markers 54 of these trackers 38 may be indistinguishable by the navigation controller 22. Thus, optimizing such trackers 38 for varying optimal characteristics allows the navigation system 12 to distinguish between such trackers 38.

[0129] In response to determining the blob 124 that corresponds to the active marker 54 of a given tracker 38 based on the optimal characteristics specific to the tracker 38, the navigation controller 22 can be configured to track the pose of the tracker 38 and to optimize the light signals emitted from the active markers 54 of the tracker 38 based on the optimal characteristics specific to the tracker 38, as described above.

[0130] In some examples, navigation controller 22 can also or alternatively be configured to optimize the optical signals emitted from the active markers 54 of tracker 38 based on the determined positions of the active markers 54 within the surgical workspace. More particularly, navigation controller 22 can be configured to determine the position of each active marker 54 within the surgical workspace based on the image data, as described above. Based on the determined positions and / or optimal characteristics of the active markers 54 within the surgical workspace, navigation controller 22 can be configured to communicate at least one control signal to tracker 38 that causes tracker 38 to adjust the optical signals emitted from at least one of the active markers 54.

[0131] For example, for each active marker 54 of a given tracker 38, navigation controller 22 can be configured to compare one or more obtained characteristics of the blob 124 corresponding to the active marker 54 with matching optimal characteristics to determine whether the blob 124 is suboptimal, as described above. In response to determining that the blob 124 corresponding to an active marker 54 is suboptimal, navigation controller 22 can be configured to communicate a control signal to tracker 38 that causes tracker 38 to adjust the light signal emitted from the active marker 54 based on the determined position of the active marker 54.

[0132] More specifically, the navigation controller 22 can be configured to compare the currently determined position of a given active marker 54 to previously determined positions of the active marker 54 within the surgical workspace to determine whether the distance between the active marker 54 and the localizer camera 18 has changed, and if so, adjust the light signal emitted from the active marker 54. For example, the navigation controller 22 can be configured to determine whether the change in distance indicates an increase or a decrease in the distance between the active marker 54 and the localizer camera 18. If the change in distance indicates an increase, then the navigation controller 22 can be configured to communicate a control signal to the tracker 38 that causes the tracker 38 to increase the intensity and / or duration of the light signal emitted from the active marker 54; if the distance decreases, then the navigation controller 22 can be configured to communicate a control signal to the tracker 38 that causes the tracker 38 to decrease the intensity and / or duration of the light signal emitted from the active marker 54. The extent to which the intensity and / or duration of the emitted light signal is increased or decreased may be proportional to the change in distance. Additionally or alternatively, the navigation controller 22 may be configured to implement a PID loop and / or stored look-up table to determine the extent to which to increase or decrease the intensity and / or duration of the emitted light signal based on changes in distance.

[0133] The navigation controller 22 may also, or alternatively, be configured to adjust the light signal emitted from at least one of the active markers 54 within the surgical workspace based on a comparison of the obtained characteristics of the blob 124 corresponding to the active marker 54 to an optimal characteristic by being configured to reposition at least one of the active markers 54 based on the comparison. More particularly, with reference to FIGS. 9A and 9B , each tracker 38 may include at least one actuator 92 for repositioning the active marker 54 of the tracker 38. For example, as shown in the illustrated example, each marker 54 of a given tracker 38 may include a dedicated actuator 92 affixed to the marker 54 configured to rotate the marker 54 relative to a body 94 of the tracker 38 to aim the active marker 54. As the marker 54 is aimed further toward the localizer camera 18, more light signals emitted from the active marker 54 can be detected by the localizer camera 18, and as the marker 54 is aimed farther away from the localizer camera 18, fewer light signals emitted from the active marker 54 can be detected by the localizer camera 18.

[0134] Each actuator 92 of a given tracker 38 is communicatively coupled to and operable by the tracker controller 56 of the tracker 38. Thus, the navigation controller 22 can be configured to reposition the active marker 54 of the tracker 38 by communicating control signals to the tracker controller 56 of the tracker 38, which in turn may change the orientation of the marker 54 relative to the localizer camera 18 by operating the actuators 92 affixed to the active marker 54. For example, FIGS. 9A and 9B show an example in which the navigation controller 22 changes the illustrated active marker 54 from pointing in the direction represented by arrow 96A to pointing in the direction represented by arrow 96B.

[0135] Thus, for each blob 124 in the received image data corresponding to a given tracker 38, the navigation controller 22 can be configured to compare one or more obtained characteristics of the blob 124 with the corresponding optimal characteristics to determine whether the blob 124 is suboptimal, as described above. In response to determining that the blob 124 is suboptimal based on the comparison, the navigation controller 22 can be configured to communicate a control signal to the tracker 38 that causes the tracker 38 to reposition the active marker 54 corresponding to the blob 124 for further iterations of the active marker 54.

[0136] As an example, assuming the acquired characteristic of each blob 124 indicates an acquired value and the corresponding optimal characteristic indicates at least one optimal value, for each blob 124, navigation controller 22 may be configured to compare the acquired value indicated for blob 124 with the at least one optimal value to determine whether the acquired value is greater than the at least one optimal value. In response to a comparison indicating that the acquired value for blob 124 is greater than the at least one optimal value, navigation controller 22 may be configured to communicate a control signal to tracker 38 that causes tracker 38 to reposition active marker 54 corresponding to blob 124 away from localizer camera 18. Conversely, in response to a comparison indicating that the acquired value for blob 124 is less than the at least one optimal value, navigation controller 22 may be configured to communicate a control signal to tracker 38 that causes tracker 38 to reposition active marker 54 corresponding to blob 124 toward localizer camera 18.

[0137] The extent to which the active marker 54 is repositioned toward or away from the localizer camera 18 may be proportional to the difference between the acquired characteristic and the optimal characteristic. Additionally or alternatively, the navigation controller 22 may be configured to implement a PID loop and / or a stored lookup table to determine the extent to which the active marker 54 is repositioned based on the difference between the acquired characteristic and the optimal characteristic.

[0138] 8 illustrates another method 200 for optimizing the tracking of a target within a surgical workspace by adjusting one or more optimal parameters of the localizer camera 18. Method 200 can be utilized when a passive tracker 38 including passive markers 54 is present within the surgical workspace. Method 200 can be facilitated by the surgical navigation system 12, such as during execution of software 64, or more particularly, by the navigation controller 22. For efficiency, specific details of blocks of method 200 that correspond to blocks of method 100 already described above will not be repeated in subsequent paragraphs.

[0139] At block 202, the trackers 38 can be positioned relative to the tracked targets. Each tracker 38 can include a predetermined geometry of the passive markers 54. At block 204, the trackers 38 can be illuminated. More specifically, the navigation controller 22 can be configured to communicate a control signal to the localizer controller 52, causing the localizer controller 52 to emit light signals from the light sources 58 within the surgical workspace. At block 206, image data can be generated based on the reflection of the light signals emitted by the passive markers 54. Specifically, the localizer controller 52 can generate image data for each optical sensor 36 representing an image showing blobs 124 corresponding to each of the passive markers 54 generated from the reflection of the emitted light signals by the passive markers 54. The pixel coordinates of each blob 124 in the image data for each optical sensor 36 can correspond to the location on the image plane of the optical sensor 36 where the reflection was detected. At block 208, each blob 124 depicted in the image data can be assigned to a passive marker 54 on the tracker 38 that corresponds to the blob 124, such as using the triangulation and fitting methods described above.

[0140] At block 210, one or more characteristics of each blob 124 may be obtained. For example, the navigation controller 22 may be configured to obtain strength characteristics, and / or size characteristics, and / or shape characteristics for each blob 124. Then, at block 212, the obtained blob characteristics may be compared to one or more optimal blob characteristics, such as blob characteristics indicated in optimal blob data 80 stored in non-volatile storage 62 of the navigation controller 22. At block 214, a determination may be made based on the comparison as to whether the blob 124 is optimal.

[0141] The navigation controller 22 can be configured to compare the acquired blob characteristics with optimal blob characteristics by combining acquired blob characteristics of the same type (e.g., intensity, size, shape) to form a combined blob characteristic of the characteristic type. For example, with respect to a blob intensity-type characteristic, the navigation controller 22 can be configured to calculate an average of the intensity values ​​indicated by the acquired intensity characteristics of the blob 124 as the combined blob characteristic for the intensity-type characteristic. With respect to a blob size-type characteristic, the navigation controller 22 can be configured to calculate an average of the areas indicated by the acquired size characteristics of the blob 124 as the combined blob characteristic for the blob size-type characteristic. With respect to a blob shape-type characteristic, the navigation controller 22 can be configured to calculate an average of the ratios indicated by the acquired shape characteristics of the blob 124 as the combined blob characteristic for the blob shape-type characteristic. The navigation controller 22 can then be configured to compare the combined blob characteristics with their corresponding optimal blob characteristics to determine whether the combined blob characteristic is optimal, as described above.

[0142] In response to determining that a given type of blob characteristic is not optimal (the "No" branch of block 214), at least one optical parameter of the localizer camera 18 can be adjusted in block 216. In one example, the optical signal emitted from the light source 58 can be adjusted to transmit an optical signal to the passive marker 54 in future tracking iterations that leads to the production of an optimal or closer to optimal type of combined blob characteristic. More specifically, the navigation controller 22 can be configured to adjust the intensity and / or duration of the optical signal emitted from the light source 58, such as by communicating a control signal to the localizer controller 52 that causes the localizer controller 52 to adjust the current applied to the light source 58, as described above.

[0143] As an example, if the combined blob characteristics indicate a value that is greater than one or more optimal values ​​defined by the corresponding optimal blob characteristics, then the navigation controller 22 can be configured to communicate a control signal to the localizer controller 52 that causes the localizer controller 52 to reduce the intensity and / or duration of the optical signal emitted from the light source 58. Conversely, if the combined blob characteristics indicate a value that is less than one or more optimal values ​​defined by the corresponding optimal blob characteristics, then the navigation controller 22 can be configured to communicate a control signal to the localizer controller 52 that causes the localizer controller 52 to increase the intensity and / or duration of the optical signal emitted from the light source 58.

[0144] The extent to which the intensity and / or duration of the emitted light signal is increased or decreased may be proportional to the difference between the acquired characteristic and the optimal characteristic. Additionally or alternatively, the navigation controller 22 may be configured to implement a PID loop and / or a stored lookup table to determine the extent to which the intensity and / or duration of the emitted light signal is increased or decreased to optimize the acquired blob characteristic.

[0145] Similar to what is described above with respect to the active markers 54, the navigation controller 22 can be configured to prioritize optimization of certain types of combined blob characteristics over other types. For example, the navigation controller 22 can be configured to first optimize the combined strength characteristic. In response to optimizing the combined strength characteristic, the navigation controller 22 can be configured to optimize the combined size characteristic. In response to optimizing the combined strength characteristic, the navigation controller 22 can be configured to optimize the combined shape characteristic. During each optimization iteration, the navigation controller 22 can be configured to obtain and check whether the highest priority combined blob characteristic type is optimal. If not, then the navigation controller 22 can be configured to adjust at least one optical parameter of the localizer camera 18 to optimize the combined blob characteristic type, as described above. If the highest priority combined blob characteristic type is determined to be optimal, then the navigation controller 22 can be configured to determine whether the next highest priority combined blob characteristic type is optimal, and so on.

[0146] In some examples, the navigation controller 22 can be configured to autonomously track and optimize the passive trackers 38 by emitting varying light signals from the light sources 58, each emitted light signal having at least one characteristic corresponding to a different tracker 38 within the surgical workspace. In other words, each emitted light signal corresponding to a different tracker 38 can have at least one characteristic, such as a light intensity characteristic or a light duration characteristic, or both, that is different from the characteristics of emitted light signals corresponding to other trackers 38 within the surgical workspace.

[0147] Based on the changing orientations of the trackers 38 within the surgical workspace, the characteristics of the blob 124 generated by one of the trackers 38 in response to an emitted light signal may vary from the characteristics of the blob 124 generated by another tracker 38 in response to the same light signal. Correspondingly, different trackers 38 may generate optimal blobs in response to emitted light signals of different characteristics. For example, one tracker 38 may generate an optimal blob 124 when the light signal emitted from the light source 58 is 90% of the full intensity level of the light source 58, another tracker 38 may generate an optimal blob 124 when the light signal emitted from the light source 58 is 80% of the full intensity level of the light source 58, and so on.

[0148] Thus, the navigation controller 22 can be configured to track and optimize the tracking of the trackers 38 by alternately emitting light signals from the light sources 58 having varying characteristics, such as having varying intensity levels ranging from 60% to 95%, and receiving image data from the localizer camera 18 corresponding to each emitted light signal indicative of a respective blob 124 of the passive markers 54 generated from the reflection of the emitted light signals by the passive markers 54. While each instance of the received image data may include the blobs 124 generated by the passive markers 54 of each tracker 38, the blob 124 corresponding to the passive marker 54 of one tracker 38 may be closer to optimal than the blob 124 corresponding to the passive marker 54 of the other tracker 38 based on the orientation of the tracker 38 within the surgical workspace and the characteristics of the emitted light signals.

[0149] Thus, for each tracker 38, the navigation controller 22 can be configured to obtain a characteristic of each blob 124 in each received instance of image data that corresponds to the marker 54 of the tracker 38, and compare the obtained characteristic to an optimal characteristic to determine which of the received image data instances is closest to optimal. In response to determining which received image data instance is closest to optimal, the navigation controller 22 can be configured to assign to the tracker 38 the optical signal characteristic that corresponds to the received image data instance, and to perform future iterations of tracking the pose of the tracker 38 within the surgical workspace based on the optical signal characteristic assigned to the tracker 38.

[0150] Thus, each tracker 38 may be assigned a particular light characteristic, and to track the pose of a given tracker 38, navigation controller 22 may be configured to emit a light signal from light source 58 specific to tracker 38, such as by emitting a light signal having the light characteristic assigned to tracker 38. Navigation controller 22 may then be configured to track the pose of tracker 38 based on blobs 124 indicated in the received image data for the emitted light signal specific to tracker 38, as described above.

[0151] The navigation controller 22 can also be configured to distinguish blobs 124 corresponding to passive markers 54 of one tracker 38 from blobs corresponding to passive markers 54 of other trackers 38 based on the lighting characteristics assigned to the one tracker 38 and one or more stored optimal characteristics. More specifically, in response to receiving image data corresponding to light signals emitted from light sources 58 having at least one characteristic corresponding to a given tracker 38, the navigation controller 22 can be configured to distinguish blobs 124 corresponding to a given tracker 38 from other trackers 38 within the surgical workspace by obtaining at least one characteristic of each blob 124 indicated by the image data, comparing the obtained characteristic of the blob 124 to the one or more optimal characteristics, and distinguishing the blob 124 based on the comparison.

[0152] For example, for each blob 124 represented by the image data, the navigation controller 22 can be configured to determine the difference between one or more acquired characteristics of the blob 124 and the corresponding one or more optimal characteristics by calculating the average of the differences or the sum of the squares of the differences. The navigation controller 22 can then be configured to determine whether the determined difference is less than a threshold and, if so, to determine that the blob 124 corresponds to the given tracker 38. In an alternative example, the navigation controller 22 can be configured to determine that the blob 124 corresponds to the given tracker 38 in response to determining that each difference between the acquired characteristic of the blob 124 and the corresponding optimal characteristic is less than a threshold.

[0153] In response to identifying the blob 124 corresponding to a given tracker 38, the navigation controller 22 can be configured to adjust the characteristics of the emitted light signal assigned to the given tracker 38 to optimize tracking of the given tracker 38, as described above. In subsequent iterations of tracking and / or tracking optimization of the given tracker 38, the navigation controller 22 can be configured to utilize the adjusted characteristics. Similar to the above, when trackers 38 are tracked and optimized using light signals emitted from light sources 58 having varying characteristics, multiple trackers 38 having substantially identical predetermined geometries of passive markers 54 may be present within the surgical workspace.

[0154] In some examples, the navigation controller 22 may also be configured to adjust at least one optical parameter of the localizer camera 18 based on the tracked pose of the tracker 38 within the surgical workspace. More specifically, the navigation controller 22 may be configured to determine the position of each passive marker 54 within the surgical workspace based on the received image data as described above, which may also indicate the pose of the tracker 38 within the surgical workspace. Based on the determined pose, the navigation controller 22 may be configured to adjust at least one optical parameter of the localizer camera 18. For example, in response to comparing the obtained characteristics of the blob 124 to optimal characteristics and determining that the blob 124 is not optimal, the navigation controller 22 may be configured to adjust at least one optical parameter of the localizer camera 18 based on the determined position of the passive marker 54.

[0155] In one example, navigation controller 22 can be configured to adjust at least one optical parameter of localizer camera 18 based on the determined positions of passive markers 54 by determining an average distance between passive markers 54 of one or more trackers 38 and localizer camera 18, comparing this average difference with previously calculated average distances of passive markers 54, and determining a change in the average distance between passive markers 54 and localizer camera 18. Navigation controller 22 can then be configured to adjust at least one optical parameter of localizer camera 18 based on the change in average distance.

[0156] For example, navigation controller 22 may be configured to determine whether a change in average distance indicates an increase or a decrease in the average distance between passive marker 54 and localizer camera 18. In response to a change in distance indicating an increase in the average distance between passive marker 54 and localizer camera 18, navigation controller 22 may be configured to increase the intensity and / or duration of the light signal emitted from light source 58 to illuminate passive marker 54. Conversely, in response to a change in distance indicating a decrease in the average distance between passive marker 54 and localizer camera 18, navigation controller 22 may be configured to decrease the intensity and / or duration of the light signal emitted from light source 58 to illuminate passive marker 54. The extent to which the intensity and / or duration of the emitted light signal is increased or decreased may be proportional to the change in average distance. Additionally or alternatively, the navigation controller 22 may be configured to implement a PID loop and / or stored look-up table to determine the extent to which to increase or decrease the intensity and / or duration of the emitted light signal to optimize the acquired blob characteristics based on changes in average distance.

[0157] In some examples, in addition to or instead of adjusting the optical signals emitted from the light sources 58, the navigation controller 22 can be configured to adjust other parameters of the localizer cameras 18 to optimize the blobs 124 generated from the markers 54. For example, the navigation controller 22 can be configured to adjust the electronic aperture time of each optical sensor 36 of the localizer cameras 18 based on a comparison of one or more acquired characteristics of the blobs 124 to one or more optimal characteristics. More particularly, the navigation controller 22 can be configured to form one or more combined blob characteristics for each optical sensor 36 from the image data generated for the optical sensors 36, and for each combined blob characteristic, as described above, and to compare the value indicated by the combined blob characteristic to the optimal value indicated by the corresponding optimal blob characteristic. In response to a comparison indicating that the value of the combined blob characteristic is greater than an optimal value, the navigation controller 22 can be configured to decrease the electronic aperture time of the corresponding optical sensor 36, and in response to a comparison indicating that the value of the combined blob characteristic is less than an optimal value, the navigation controller 22 can be configured to increase the electronic aperture time of the corresponding optical sensor 36.

[0158] As a further example, localizer camera 18 may also include a mechanical shutter and / or a mechanical aperture for each optical sensor 36, and navigation controller 22 may be configured to adjust the shutter time of the mechanical shutter and / or adjust the capture size of the mechanical aperture of each optical sensor 36 based on a comparison of one or more acquired characteristics of blobs 124 to one or more optimal characteristics. More specifically, navigation controller 22 may be configured to form one or more combined blob characteristics for each optical sensor 36 from the image data generated for the optical sensors 36, as described above, and, for each combined blob characteristic, compare the value indicated by the combined blob characteristic to an optimal value indicated by the corresponding optimal blob characteristic. In response to a comparison indicating the value of the combined blob characteristic is greater than the optimal value, navigation controller 22 may be configured to decrease the shutter time of the mechanical shutter and / or the capture size of the mechanical aperture of the optical sensor 36, and in response to a comparison indicating the value of the combined blob characteristic is less than the optimal value, navigation controller 22 may be configured to increase the shutter time of the mechanical shutter and / or the capture size of the mechanical aperture of the optical sensor 36.

[0159] Referring again to FIG. 8 , in response to determining that each of the combined blob characteristics is optimal (the “Yes” branch of block 214), or in response to adjusting at least one optical parameter of the localizer camera 18 in block 216, method 200 may return to block 204 to again illuminate the tracker 38 via the light source 58 of the localizer camera 18.

[0160] In some examples, the passive marker 54 of each tracker 38 may be manually repositionable, and the navigation controller 22 may also be configured to determine and display, such as on the display 28, 30, guidance for repositioning at least one passive marker 54 of the tracker 38 based on a comparison of the obtained characteristics of the blob 124 to optimal characteristics. For example, with reference to FIGS. 10 and 10B , each passive marker 54 of a given tracker 38 may be mounted in a rotatable socket 98 that allows a user to manually rotate the passive marker 54 relative to the body 94 of the tracker 38 to aim the passive marker 54 toward and away from the localizer camera 18.

[0161] Thus, for each blob 124 indicated by the received image data, the navigation controller 22 may be configured to assign the blob 124 to a passive marker 54 corresponding to the blob 124, compare one or more acquired characteristics of the blob 124 with one or more optimal corresponding optimal characteristics to determine whether the blob 124 is suboptimal, and, based on the comparison, determine and display guidance for relocating the passive marker 54 corresponding to the blob 124 in response to determining that the blob 124 is suboptimal.

[0162] For example, assuming the acquired characteristic of each blob 124 indicates an acquired value and the corresponding optimal characteristic indicates an optimal value, for each blob, the navigation controller 22 can be configured to assign the blob 124 to a passive marker 54 corresponding to the blob 124 and compare the acquired value indicated for the blob 124 to the optimal value. In response to a comparison indicating that the acquired value for the blob 124 is greater than the optimal value, the navigation controller 22 can be configured to determine and display guidance for repositioning the passive marker 54 corresponding to the blob 124 away from the localizer camera 18. Conversely, in response to a comparison indicating that the acquired value for the blob 124 is less than the optimal value, the navigation controller 22 can be configured to reposition the passive marker 54 corresponding to the blob 124 toward the localizer camera 18.

[0163] Some surgical environments may incorporate both passive and active trackers 38. In this case, navigation controller 22 may be configured to implement both the above-described process for optimizing the active tracker 38 and the above-described process for optimizing the passive tracker 38. In one example, navigation controller 22 may be configured to alternate between optimizing and tracking the active and passive trackers 38 using the above-described process. Alternatively, navigation controller 22 may be configured to implement both the tracking and optimization processes simultaneously, such as by causing markers 54 of the active tracker 38 to emit light signals at different frequencies as light signals emitted from light sources 58 to reduce interference between and improve discrimination between types of trackers 38, and / or by utilizing varying sets of one or more optimal blob characteristics of different tracker types to further facilitate such discrimination.

[0164] In general, the routines executed to implement aspects of the above description may be referred to herein as "computer program code" or simply "program code," whether implemented as part of an operating system or as a specific application, component, program, object, module, or sequence of instructions, or a subset thereof. Program code may reside in various memory and storage devices in a computer at various times and include computer-readable instructions that, when read and executed by one or more processors in the computer, cause the computer to perform the operations necessary to carry out the acts and / or elements embodying various aspects of the specification. Computer-readable program instructions for carrying out the operations of various aspects of the specification may be either source code or object code written, for example, in assembly language or any combination of one or more programming languages.

[0165] The program code embodied in any of the applications / modules described herein may be distributed individually or collectively as a program product in a variety of different forms. In particular, the program code may be distributed using a computer-readable storage medium having computer-readable program instructions for causing a processor to implement aspects of the specification.

[0166] Computer-readable storage media that are non-transitory in nature may include volatile and non-volatile, removable and non-removable tangible media implemented in any method or technology for storage of information, such as computer-readable instructions, data structures, program modules, or other data. Computer-readable media may also include random access memory (RAM), read-only memory (ROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), flash memory or other solid-state memory technology, portable compact disc read-only storage (CD-ROM), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage, or other magnetic storage devices, or any other medium that can be used to store desired information and can be read by a computer. Computer-readable storage media should not be construed as transient signals (e.g., radio waves or other propagating electromagnetic waves, electromagnetic waves propagating through a transmission medium such as a waveguide, or electrical signals transmitted through wires) themselves. Computer-readable program instructions may be downloaded from the computer-readable storage medium to a computer, another type of programmable data processing device, or another device, or to an external computer or external storage device via a network.

[0167] Computer-readable program instructions stored on a computer-readable medium may be used to direct a computer, other type of programmable data processing apparatus, or other device to function in a particular manner, such that the instructions stored on the computer-readable medium produce an article of manufacture including instructions that perform the functions / acts specified in the flowcharts, sequence diagrams, and / or block diagrams. The computer program instructions, when executed by one or more processors, may provide one or more processors with a series of calculations that cause the processors to implement the functions and / or acts specified in the flowcharts, sequence diagrams, and / or block diagrams described herein.

[0168] In certain alternatives, the functions and / or acts specified in the flowcharts, sequence diagrams, and / or block diagrams may be reordered, processed sequentially, and / or processed simultaneously without departing from the scope of the invention. Additionally, any of the flowcharts, sequence diagrams, and / or block diagrams may include more or fewer blocks than those illustrated herein.

[0169] The terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that the terms "comprise" and / or "comprising," as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Furthermore, to the extent that "includes," "having," "has," "with," "comprise of," or variations thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprising."

[0170] While a description of various examples has been provided, and these examples have been described in considerable detail, it is not the intention of applicants to restrict or in any way limit the scope of the appended claims to such details. Additional advantages and modifications will be readily apparent to those skilled in the art. Accordingly, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicants' general inventive concept. In order to maintain the disclosure matters as originally filed, the contents of claims 1 to 76 as originally filed are added below. (Claim 1) 1. A navigation system for optimizing tracking of a target within a surgical workspace, comprising: a tracker positioned relative to the target, the tracker having active markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera configured to cooperate with the tracker to generate image data indicative of each blob of the active markers generated from optical signals emitted from the active markers; a controller communicatively coupled to the tracker and the localizer camera, assigning each of the blobs to the active marker corresponding to the blob; Get the characteristics of each blob, comparing the obtained characteristics with optimal characteristics; communicating at least one control signal to the tracker that causes the tracker to adjust the optical signal emitted from at least one of the active markers based on the comparison. The controller configured to A navigation system comprising: (Claim 2) 10. The navigation system of claim 1, wherein the at least one control signal communicated to the tracker causes the tracker to adjust an intensity or a duration, or both, of the optical signal emitted from the at least one of the active markers. (Claim 3) For each of the blobs, the controller: comparing the obtained characteristics of the blob with the optimal characteristics to determine if the blob is suboptimal; and in response to determining that the blob is not optimal based on the comparison, communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker corresponding to the blob. 3. The navigation system according to claim 1, wherein the navigation system is configured as follows: (Claim 4) The obtained characteristic of each blob exhibits a first value and the optimal characteristic exhibits a second value, and for each blob, the controller: comparing the first value indicated for the blob to the second value; communicating a control signal to the tracker that causes the tracker to reduce an intensity or duration, or both, of the optical signal emitted from the active marker corresponding to the blob in response to the comparison indicating that the first value for the blob is greater than the second value; In response to the comparison indicating that the first value of the blob is less than the second value, communicating a control signal to the tracker that causes the tracker to increase the intensity or duration, or both, of the light signal emitted from the active marker corresponding to the blob. 4. The navigation system according to claim 1, configured as follows: (Claim 5) 5. The navigation system according to claim 1, wherein the acquired characteristic is a blob intensity characteristic, and the optimum characteristic is an optimum blob intensity characteristic. (Claim 6) 5. The navigation system according to claim 1, wherein the acquired characteristic is a blob size characteristic, and the optimum characteristic is an optimum blob size characteristic. (Claim 7) 5. The navigation system according to claim 1, wherein the acquired characteristics are blob shape characteristics, and the optimum characteristics are optimum blob shape characteristics. (Claim 8) The acquired characteristic is defined as an acquired first characteristic, the optimal characteristic is defined as a first optimal characteristic, and the controller: obtaining one or more second characteristics of one or more of the blobs; comparing the one or more obtained second characteristics to a second optimum characteristic; communicating at least one control signal to the tracker that causes the tracker to adjust the optical signal emitted from at least one of the one or more active markers corresponding to the one or more blobs based on the comparison of the one or more obtained second characteristics to the second optimal characteristic. 5. The navigation system according to claim 1, wherein the navigation system is configured as described above. (Claim 9) The acquired characteristic is defined as an acquired first characteristic, the optimal characteristic is defined as a first optimal characteristic, and the controller: comparing the obtained first characteristic of the blob to the first optimal characteristic to determine if the obtained first characteristic of the blob is not optimal; communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker corresponding to the blob in response to determining, based on the comparison, that the obtained first characteristic of the blob is not optimal; In response to determining that the obtained first characteristic of the blob is best based on the comparison, obtaining a second property of the blob; comparing the obtained second characteristic of the blob with a second optimal characteristic to determine if the obtained second characteristic of the blob is not optimal; and in response to determining, based on the comparison, that the obtained second characteristic of the blob is not optimal, communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker corresponding to the blob. 9. The navigation system according to claim 1, wherein the navigation system is configured as described above. (Claim 10) 10. The navigation system of claim 8 or 9, wherein the acquired first property is a blob intensity property, and the acquired second property is a blob size property or a blob shape property. (Claim 11) the image data includes first image data corresponding to a first optical sensor of the localizer camera and second image data corresponding to a second optical sensor of the localizer camera, each of the first and second image data representing a blob of each active marker generated from an optical signal emitted from the active marker, and the controller: identifying a first blob from the first image data and a second blob from the second image data, the first blob and the second blob corresponding to the same active marker; obtaining a first characteristic of the first blob and a second characteristic of the second blob; combining the obtained first feature and the obtained second feature to form a combined blob feature; comparing the combined blob characteristics to the optimal characteristics to determine if the combined blob characteristics are not optimal; and in response to determining, based on the comparison, that the combined blob characteristics are not optimal, communicating a control signal to the tracker that causes the tracker to adjust the optical signals emitted from the active markers corresponding to the first and second blobs. 3. The navigation system according to claim 1 or 2, configured to: (Claim 12) 12. The navigation system of claim 11, wherein the first and second acquired characteristics are acquired intensity characteristics, and the optimal characteristic is an optimal blob intensity characteristic. (Claim 13) 13. The navigation system of claim 5 or 12, wherein the optimal blob intensity characteristic exhibits an intensity value that is greater than or equal to 75% and less than or equal to 95% of the full intensity value of the localizer camera. (Claim 14) The combined blob characteristic is defined as a first combined blob characteristic, the optimal characteristic is defined as a first optimal characteristic, and the controller: obtaining a third characteristic of the first blob and a fourth characteristic of the second blob; combining the obtained third feature and the obtained fourth feature to form a second combined blob feature; comparing the second combined blob characteristic to a second optimal characteristic; communicating a control signal to the tracker that causes the tracker to adjust the optical signals emitted from the active markers corresponding to the first and second blobs based on the comparison of the second combined blob characteristic to the second optimal characteristic. The navigation system according to claim 11, configured to: (Claim 15) The combined blob characteristic is defined as a first combined blob characteristic, the optimal characteristic is defined as a first optimal characteristic, and the controller: comparing the first combined blob characteristic to the first optimal characteristic to determine if the first combined blob characteristic is not optimal; in response to determining that the first combined blob characteristic is not optimal, communicating a control signal to the tracker that causes the tracker to adjust the optical signals emitted from the active markers corresponding to the first and second blobs; In response to determining that the first combined blob characteristic is best based on the comparison, obtaining a third characteristic of the first blob and a fourth characteristic of the second blob; combining the obtained third feature and the obtained fourth feature to form a second combined blob feature; comparing the second combined blob characteristic to the second optimal characteristic to determine if the second combined blob characteristic is not optimal; and in response to determining, based on the comparison, that the second combined blob characteristic is not optimal, communicating a control signal to the tracker that causes the tracker to adjust the optical signals emitted from the active markers corresponding to the first and second blobs. 15. The navigation system according to claim 11 or 14, configured as follows: (Claim 16) 16. The navigation system of claim 14 or 15, wherein the acquired first and second properties are blob intensity properties, and the acquired third and fourth properties are blob size properties or blob shape properties. (Claim 17) the target object is defined as a first target object, the blob is defined as a first blob, the tracker is defined as a first tracker, the acquired characteristic is defined as an acquired first characteristic, and the optimal characteristic is defined as a first optimal characteristic specific to the first tracker; and the surgical system further comprises a second tracker positioned relative to a second target object within the surgical workspace, the second tracker having a predefined geometry of active markers for tracking a pose of the second tracker within the surgical workspace, the image data generated by the localizer camera including second blobs for each of the active markers of the second tracker generated from optical signals emitted from the active markers of the second tracker; and assigning each of the second blobs to the active marker of the second tracker corresponding to the second blob; Obtaining a second characteristic of each second blob; comparing the obtained second characteristic with a second optimal characteristic that is specific to the second tracker and different from the first optimal characteristic; communicating at least one control signal to the second tracker that causes the second tracker to adjust the optical signal emitted from at least one of the active markers of the second tracker based on the comparison. 17. The navigation system according to claim 1, configured as follows: (Claim 18) 18. The navigation system of claim 17, wherein the controller is configured to assign the first blob to the active marker of the first tracker based on the first optimal characteristic, and / or assign the second blob to the active marker of the second tracker based on the second optimal characteristic. (Claim 19) For each of the first blobs, the controller: determining a difference between the obtained first characteristic of the first blob and the first optimum characteristic; determining whether the difference between the obtained first characteristic and the first optimal characteristic of the first blob is less than a threshold; In response to determining that the difference between the acquired first characteristic and the first optimal characteristic of the first blob is less than the threshold, determine that the first blob corresponds to the first tracker and assign the first blob to the active marker of the first tracker corresponding to the first blob. 19. The navigation system according to claim 17 or 18, configured to: (Claim 20) 20. The navigation system of claim 17, wherein the predefined geometries of the active markers of the first tracker and the predefined geometries of the active markers of the second tracker are substantially equivalent. (Claim 21) The controller: determining a position of the active marker of the tracker within the surgical workspace based on the image data; communicating the at least one control signal to the tracker that causes the tracker to adjust the optical signal emitted from at least one of the active markers based on the determined positions of the active markers. 21. The navigation system according to claim 1, configured as described above. (Claim 22) For each of the active markers, the controller: comparing the obtained characteristics of the blob corresponding to the active marker with the optimal characteristics to determine whether the blob corresponding to the active marker is not optimal; In response to determining that the blob corresponding to the active marker is not optimal, communicate a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the determined position of the active marker. 22. The navigation system of claim 21, configured to: (Claim 23) The controller: comparing the determined position of the active marker to a previously determined position of the active marker to determine a change in distance between the active marker and the localizer camera; communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the change in distance. 23. The navigation system of claim 22, wherein the navigation system is configured to communicate a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the determined position of the active marker. (Claim 24) The controller determining whether the change in distance indicates an increase or a decrease in the distance between the active marker and the localizer camera; in response to the change in distance indicating an increase in the distance between the active marker and the localizer camera, communicating a control signal to the tracker that causes the tracker to increase an intensity and / or duration of the light signal emitted from the active marker; communicating a control signal to the tracker that causes the tracker to reduce an intensity and / or duration of the optical signal emitted from the active marker in response to the change in distance indicating a decrease in the distance between the active marker and the localizer camera. 24. The navigation system of claim 23, wherein the navigation system is configured to communicate a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the determined change in distance. (Claim 25) 1. A navigation system for optimizing tracking of a target within a surgical workspace, comprising: a first tracker positioned relative to a first target within the surgical workspace, the first tracker having active markers of predefined geometry for tracking a pose of the first tracker within the surgical workspace; a second tracker positioned relative to a second target within the surgical workspace, the second tracker having active markers of predefined geometry for tracking a pose of the second tracker within the surgical workspace; a localizer camera configured to cooperate with the first and second trackers to generate image data indicative of a first blob for each of the active markers of the first tracker generated from optical signals emitted from the active markers, and a second blob for each of the active markers of the second tracker generated from optical signals emitted from the active markers; a controller communicatively coupled to the first and second trackers and the localizer camera, obtaining a characteristic of each of the first and second blobs; comparing the obtained characteristic with a first optimum characteristic specific to the first tracker and a second optimum characteristic specific to the second tracker, the second optimum characteristic being different from the first optimum characteristic; Based on the comparison, assigning the first blob to the first tracker and the second blob to the second tracker. The controller is configured to A navigation system comprising: (Claim 26) 1. A navigation system for optimizing tracking of a target within a surgical workspace, comprising: a tracker positioned relative to the target, the tracker having active markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera configured to cooperate with the tracker to generate image data indicative of each blob of the active markers generated from optical signals emitted from the active markers; a controller communicatively coupled to the tracker and the localizer camera, determining a position of the active marker of the tracker within the surgical workspace based on the image data; communicating at least one control signal to the tracker based on the determined positions of the active markers, the control signal causing the tracker to adjust the optical signal emitted from at least one of the active markers based on the determined positions. The controller configured to A navigation system comprising: (Claim 27) 1. A navigation system for optimizing tracking of a target within a surgical workspace, comprising: a tracker positioned relative to the target, the tracker having a predefined geometry of passive markers for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit a light signal to illuminate the passive marker, the localizer camera configured to generate image data indicative of each blob of the passive marker generated from reflection by the passive marker of the light signal emitted from the light source; a controller communicatively coupled to the localizer camera, Get the characteristics of each blob, comparing the obtained characteristics with optimal characteristics; adjusting at least one optical parameter of the localizer camera based on the comparison; The controller is configured to A navigation system comprising: (Claim 28) 28. The navigation system of claim 27, wherein the controller is configured to adjust at least one optical parameter of the localizer camera based on the comparison by being configured to adjust an intensity and / or duration of the optical signal emitted from the light source to illuminate the passive marker based on the comparison. (Claim 29) The controller: combining the obtained features to form a combined blob feature; comparing the combined blob characteristics to the optimal characteristics to determine if the combined blob characteristics are not optimal; adjusting the at least one optical parameter of the localizer camera in response to determining that the combined blob characteristics are not optimal based on the comparison. 29. The navigation system according to claim 27 or 28, configured to: (Claim 30) The acquired characteristic is defined as an acquired first characteristic, the combined blob characteristic is defined as a first combined blob characteristic, and the optimal characteristic is defined as a first optimal characteristic, and the controller: comparing the first combined blob characteristic to the first optimal characteristic to determine if the first combined blob characteristic is not optimal; adjusting the at least one optical parameter of the localizer camera in response to determining, based on the comparison, that the first combined blob characteristic is not optimal; In response to determining that the first combined blob characteristic is best based on the comparison, Obtain a second property of each blob, combining the obtained second features to form a second combined blob feature; comparing the second combined blob characteristic to the second optimal characteristic to determine if the second combined blob characteristic is not optimal; adjusting the at least one optical parameter of the localizer camera in response to determining that the second combined blob characteristic is not optimal based on the comparison. 30. The navigation system according to claim 27, wherein the navigation system is configured as described above. (Claim 31) the target is defined as a first target, the blob is defined as a first blob, the tracker is defined as a first tracker, and the optical signal is defined as a first optical signal specific to the first tracker; and the surgical system further comprises a second tracker positioned relative to a second target within the surgical workspace, the second tracker having a predefined geometry of passive markers for tracking a pose of the second tracker within the surgical workspace, and the controller: emitting a second optical signal from the light source that is specific to the second tracker, the second optical signal having at least one characteristic that is different from at least one corresponding characteristic of the first optical signal; receiving image data corresponding to the second optical signal generated by the localizer camera, the received image data indicating a second blob for each of the passive markers of the second tracker generated from reflection by the passive marker of the second optical signal emitted from the light source; obtaining a characteristic of each second blob; comparing the obtained characteristic of the second blob with the optimal characteristic to determine whether the obtained characteristic of the second blob is not optimal; adjusting the at least one characteristic of the second optical signal in response to determining, based on the comparison, that the obtained characteristic of the second blob is not optimal; and 31. The navigation system according to claim 27, wherein the navigation system is configured to perform the above. (Claim 32) 32. The navigation system of claim 31, wherein the at least one characteristic of the second optical signal that differs from the at least one corresponding characteristic of the first optical signal includes a light intensity characteristic, a light duration characteristic, or both. (Claim 33) 33. The navigation system of claim 31 or 32, wherein the image data corresponding to the second optical signal indicates a third blob for each of the passive markers of the first tracker generated from reflection by the passive marker of the second optical signal emitted from the light source, and wherein the controller is configured, in response to receiving the image data corresponding to the second optical signal, to distinguish the second blob from the third blob based on the optimal characteristic. (Claim 34) 34. The navigation system of claim 31, wherein the predefined geometries of the passive markers of the first tracker and the predefined geometries of the passive markers of the second tracker are substantially equivalent. (Claim 35) The controller: emitting an optical signal having a varying characteristic from the light source; receiving image data generated by the localizer camera for each of the emitted light signals indicative of a blob of each of the passive markers generated from reflection of the emitted light signals by the passive markers; for each instance of received image data, obtaining a characteristic of each blob represented by said image data, and comparing said obtained characteristic to said optimum characteristic to determine which of said instances of said received image data is closest to optimum; assigning, to the tracker, the characteristic of the optical signal that corresponds to the received image data instance in response to determining which instance of the received image data is closest to optimal; Tracking a pose of the tracker within the surgical workspace based on the optical signal characteristic assigned to the tracker. 35. The navigation system according to claim 27, configured as follows: (Claim 36) The controller: emitting a light signal from the light source having the light signal characteristic assigned to the tracker to illuminate the passive marker of the tracker; receiving image data corresponding to the emitted optical signal having the optical signal characteristic assigned to the tracker, the received image data indicating a blob for each passive marker of the tracker generated from a reflection of the emitted optical signal having the optical signal characteristic assigned to the tracker by the passive marker; obtaining characteristics of each of the blobs in the received image data; comparing the acquired characteristics of the blobs in the received image data with the optimal characteristics to determine if the acquired characteristics of the blobs are not optimal; adjusting the optical signal characteristic assigned to the tracker in response to determining, based on the comparison, that the obtained characteristic of the blob is not optimal; and 36. The navigation system of claim 35, configured to: (Claim 37) The controller: determining a position of the passive marker of the tracker within the surgical workspace based on the image data; adjusting the at least one optical parameter of the localizer camera based on the determined position of the passive marker. 37. The navigation system according to claim 27, wherein the navigation system is configured as follows. (Claim 38) 38. The navigation system of claim 27, wherein the controller is configured to adjust an electronic aperture time of the localizer camera based on the comparison, thereby adjusting the at least one optical parameter of the localizer camera based on the comparison. (Claim 39) 39. The navigation system of claim 27, wherein the localizer camera includes a mechanical shutter, and wherein the controller is configured to adjust a shutter time of the mechanical shutter based on the comparison, thereby adjusting the at least one optical parameter of the localizer camera based on the comparison. (Claim 40) 40. The navigation system of claim 27, wherein the localizer camera includes a mechanical aperture, and the controller is configured to adjust the at least one optical parameter of the localizer camera based on the comparison by being configured to adjust a capture size of the mechanical aperture based on the comparison. (Claim 41) 1. A navigation system for tracking a target within a surgical workspace, comprising: a first tracker positioned relative to a first target within the surgical workspace, the first tracker having a predefined geometry of passive markers for tracking a pose of the first tracker within the surgical workspace; a second tracker positioned relative to a second target within the surgical workspace, the second tracker including a predefined geometry of passive markers for tracking a pose of the second tracker within the surgical workspace; a localizer camera including a light source configured to emit light signals to illuminate the passive markers of the first and second trackers, the localizer camera configured to generate image data indicative of blobs of each of the passive markers of the first and second trackers generated from reflections by the passive markers of the light signals emitted from the light source; a controller communicatively coupled to the localizer camera, emitting a first optical signal from the light source, the first optical signal being specific to the first tracker; receiving image data generated by the localizer camera corresponding to the emitted first optical signal; tracking a pose of the first tracker within the surgical workspace based on the received image data corresponding to the first optical signal; emitting a second optical signal from the light source, the second optical signal having at least one characteristic that is specific to the second tracker and that differs from at least one corresponding characteristic of the first optical signal; receiving image data generated by the localizer camera corresponding to the emitted second optical signal; Tracking a pose of the second tracker within the surgical workspace based on the received image data corresponding to the second optical signal. The controller is configured to A navigation system comprising: (Claim 42) 1. A navigation system for optimizing tracking of a target within a surgical workspace, comprising: a tracker positioned relative to the target, the tracker having passive markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit a light signal to illuminate the passive marker, the localizer camera configured to generate image data indicative of each blob of the passive marker generated from reflection by the passive marker of the light signal emitted from the light source; a controller communicatively coupled to the localizer camera, emitting an optical signal having a varying characteristic from the light source; receiving image data generated by the localizer camera for each of the emitted light signals indicative of a blob of each of the passive markers generated from reflection of the emitted light signals by the passive markers; For each instance of received image data, obtaining a characteristic of each blob represented by said image data and comparing said obtained characteristic to an optimum characteristic to determine which of said instances of received image data is closest to an optimum; assigning, to the tracker, the characteristic of the optical signal that corresponds to the received image data instance in response to determining which instance of the received image data is closest to optimal; Tracking a pose of the tracker within the surgical workspace based on the optical signal characteristic assigned to the tracker. The controller is configured to A navigation system comprising: (Claim 43) 1. A navigation system for optimizing tracking of a target within a surgical workspace, comprising: a tracker positioned relative to the target, the tracker having passive markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit a light signal to illuminate the passive marker, the localizer camera configured to generate image data indicative of each blob of the passive marker generated from reflection by the passive marker of the light signal emitted from the light source; a controller communicatively coupled to the localizer camera, determining a position of the passive marker of the tracker within the surgical workspace based on the image data; adjusting at least one optical parameter of the localizer camera based on the determined position of the passive marker. The controller is configured to A navigation system comprising: (Claim 44) 1. A navigation system for optimizing tracking of a target within a surgical workspace, comprising: a tracker positioned relative to the target, the tracker having passive markers of predefined geometry that can be manually repositioned to track the orientation of the tracker within the surgical workspace; a localizer camera including a light source configured to emit a light signal to illuminate the passive marker, the localizer camera configured to generate image data indicative of each blob of the passive marker generated from reflection by the passive marker of the light signal emitted from the light source; a controller communicatively coupled to the localizer camera, Get the characteristics of each blob, comparing the obtained characteristics with optimal characteristics; determining and displaying guidance for repositioning the passive marker of the tracker based on the comparison; The controller is configured to A navigation system comprising: (Claim 45) 1. A method for optimizing tracking of a target within a surgical workspace by a navigation system including: a tracker positioned relative to the target, the tracker having active markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera configured to cooperate with the tracker to generate image data indicative of respective blobs of the active markers generated from optical signals emitted from the active markers; and a controller communicatively coupled to the tracker and the localizer camera, The controller: positioning the tracker relative to the target within the surgical workspace; generating, by the localizer camera, the image data indicative of each blob of the active markers generated from optical signals emitted from the active markers; assigning, by the controller, each of the blobs to the active marker corresponding to the blob; obtaining, by said controller, characteristics of each blob; comparing the obtained characteristics with an optimum characteristic by the controller; communicating, by the controller, at least one control signal to the tracker based on the comparison, the control signal causing the tracker to adjust the optical signal emitted from at least one of the active markers. A method configured to: (Claim 46) 46. ​​The method of claim 45, wherein the at least one control signal communicated to the tracker causes the tracker to adjust an intensity or a duration, or both, of the light signal emitted from the at least one of the active markers. (Claim 47) comparing the obtained characteristics of each of the blobs with the optimal characteristics to determine if the blob is suboptimal; identifying one or more of the blobs as non-best based on the comparison; and for each of the identified one or more blobs, communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker corresponding to the blob; 47. The method of claim 45 or 46, further comprising: (Claim 48) the obtained characteristic of each blob exhibits a first value and the optimal characteristic exhibits a second value; comparing the first value indicated for each of the blobs to the second value to determine whether the first value is greater than the second value; identifying one or more of the blobs for which the first value is greater than the second value based on the comparison; for each of the identified one or more blobs where the first value is greater than the second value, communicating a control signal to the tracker that causes the tracker to reduce an intensity and / or duration of the optical signal emitted from the active marker corresponding to the blob; 48. The method according to any one of claims 45 to 47, further comprising: (Claim 49) the obtained characteristic of each blob exhibits a first value and the optimal characteristic exhibits a second value; comparing the indicated first value for each of the blobs to the second value to determine whether the first value is less than the second value; identifying one or more of the blobs for which the first value is less than the second value based on the comparison; for each of the identified one or more blobs for which the first value is less than the second value, communicating a control signal to the tracker that causes the tracker to increase the intensity or duration, or both, of the optical signal emitted from the active marker corresponding to the blob; 49. The method according to any one of claims 45 to 48, further comprising: (Claim 50) 50. The method of any one of claims 45 to 49, wherein the obtained property is a blob intensity property and the optimal property is an optimal blob intensity property. (Claim 51) 50. The method of any one of claims 45 to 49, wherein the obtained property is a blob size property and the optimal property is an optimal blob size property. (Claim 52) 50. The method of any one of claims 45 to 49, wherein the obtained properties are blob shape properties and the optimal properties are optimal blob shape properties. (Claim 53) The acquired characteristic is defined as an acquired first characteristic, the optimal characteristic is defined as a first optimal characteristic, and the controller: obtaining one or more second characteristics of one or more of the blobs; comparing the one or more obtained second characteristics to a second optimum characteristic; communicating at least one control signal to the tracker that causes the tracker to adjust the optical signal emitted from at least one of the one or more active markers corresponding to the one or more blobs based on the comparison of the one or more obtained second characteristics to the second optimal characteristic; 50. The method according to any one of claims 45 to 49, comprising: (Claim 54) The acquired characteristic is defined as an acquired first characteristic, and the optimal characteristic is defined as a first optimal characteristic; comparing the obtained first characteristic of each of the blobs with the first optimal characteristic to determine whether the obtained first characteristic of the blob is not optimal; identifying, from the blobs, one or more first blobs each having the best first optimum characteristic based on the comparison of the obtained first characteristic to the first optimum characteristic; obtaining a second characteristic of each of the one or more first blobs; comparing the obtained second characteristic of each of the one or more blobs to a second optimal characteristic to determine whether the obtained second characteristic of the blob is not optimal; identifying, from the one or more first blobs, each of one or more second blobs for which the second optimum characteristic is not the best based on the comparison of the obtained second characteristic to the second optimum characteristic; for each of the identified one or more second blobs, communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker corresponding to the blob; 54. The method according to any one of claims 45 to 49 and 53, further comprising: (Claim 55) 55. The method of claim 53 or 54, wherein the first property obtained is a blob intensity property and the second property obtained is a blob size property or a blob shape property. (Claim 56) the image data includes first image data corresponding to a first optical sensor of the localizer camera and second image data corresponding to a second optical sensor of the localizer camera, each of the first and second image data representing a blob of each active marker generated from an optical signal emitted from the active marker; For each of the active markers: identifying a first blob from the first image data and a second blob from the second image data corresponding to the active marker; obtaining a first characteristic of the first blob and a second characteristic of the second blob; combining the obtained first characteristic and the obtained second characteristic to form a combined blob characteristic; comparing the combined blob characteristics to the optimal characteristics to determine if the combined blob characteristics are not optimal; identifying one or more of the combined blob characteristics as suboptimal based on the comparison of each of the combined blob characteristics to the optimal characteristic; for each of the identified one or more combined blob characteristics, communicating a control signal to the tracker that causes the tracker to adjust the light signal emitted from the active marker corresponding to the combined blob characteristic; 47. The method of claim 45 or 46, further comprising: (Claim 57) 57. The method of claim 56, wherein the first and second properties are acquired intensity properties and the optimal property is an optimal blob intensity property. (Claim 58) 58. The method of claim 50 or 57, wherein the optimal blob intensity characteristic exhibits an intensity value that is greater than or equal to 75% and less than or equal to 95% of the full intensity value of the localizer camera. (Claim 59) The combined blob characteristic is defined as a first combined blob characteristic, the optimal characteristic is defined as a first optimal characteristic, and the controller: For each of one or more of the active markers: obtaining a third characteristic of the first blob and a fourth characteristic of the second blob corresponding to the active marker; combining the obtained third feature and the obtained fourth feature to form a second combined blob feature; comparing the second combined blob characteristic to a second optimal characteristic; communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from at least one of the one or more active markers based on the comparison of the second combined blob characteristic of each of the one or more active markers to the second optimal characteristic. 57. The method of claim 56, wherein the method is configured to: (Claim 60) the combined blob characteristic is defined as a first combined blob characteristic, and the optimal characteristic is defined as a first optimal characteristic; identifying one or more of the first combined blob characteristics as best based on the comparison of each of the one or more first combined blob characteristics to the optimal characteristic; For each of the one or more first combined blob characteristics identified as being best, obtaining a third characteristic of the first blob and a fourth characteristic of the second blob corresponding to the first combined blob characteristic; combining the obtained third characteristic and the obtained fourth characteristic to form a second combined blob characteristic; comparing the second combined blob characteristic to the second optimal characteristic to determine whether the second combined blob characteristic is not optimal; and in response to determining, based on the comparison, that the second combined blob characteristic is not optimal, communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker that corresponds to the first combined blob characteristic. 60. The method of claim 56 or 59, further comprising: (Claim 61) 61. The method of claim 59 or 60, wherein the first and second acquired properties are blob intensity properties, and the third and fourth acquired properties are blob size properties or blob shape properties. (Claim 62) the target is defined as a first target, the blob is defined as a first blob, the tracker is defined as a first tracker, the acquired characteristic is defined as an acquired first characteristic, and the optimal characteristic is defined as a first optimal characteristic specific to the first tracker; positioning a second tracker relative to a second landmark within the surgical workspace, the second tracker having a predefined geometry of active markers for tracking a pose of the second tracker within the surgical workspace, and the image data generated by the localizer camera including second blobs for each of the active markers of the second tracker generated from optical signals emitted from the active markers of the second tracker; assigning each of the second blobs to the active marker of the second tracker corresponding to the second blob; obtaining a second characteristic of each second blob; comparing the obtained second characteristic to a second optimal characteristic that is specific to the second tracker and different from the first optimal characteristic; communicating at least one control signal to the second tracker that causes the second tracker to adjust the optical signal emitted from at least one of the active markers of the second tracker based on the comparison of the obtained second characteristic to a second optimal characteristic; 62. The method according to any one of claims 45 to 61, further comprising: (Claim 63) 63. The method of claim 62, further comprising assigning the first blob to the active marker of the first tracker based on the first optimal characteristic, and / or assigning the second blob to the active marker of the second tracker based on the second optimal characteristic. (Claim 64) For each of the first blobs: determining a difference between the obtained first characteristic of the first blob and the first optimum characteristic; determining that the difference between the obtained first characteristic and the first optimal characteristic of the first blob is less than a threshold; in response to determining that the difference between the acquired first characteristic and the first optimal characteristic of the first blob is less than the threshold, determining that the first blob corresponds to the first tracker and assigning the first blob to the active marker of the first tracker corresponding to the first blob; 64. The method of claim 62 or 63, further comprising: (Claim 65) 65. The method of any one of claims 61 to 64, wherein the predefined geometries of the active markers of the first tracker and the predefined geometries of the active markers of the second tracker are substantially equivalent. (Claim 66) determining a position of the active marker of the tracker within the surgical workspace based on the image data; communicating the at least one control signal to the tracker that causes the tracker to adjust the optical signal emitted from at least one of the active markers based on the determined positions of the active markers; 66. The method according to any one of claims 45 to 65, further comprising: (Claim 67) comparing the obtained characteristics of each of the blobs with the optimal characteristics to determine if the blob is suboptimal; identifying one or more of the blobs as non-best based on the comparison; and for each of the one or more blobs identified as non-best, communicating a control signal to the tracker that causes the tracker to adjust the light signal emitted from the active marker corresponding to the blob based on the determined position of the active marker; 67. The method of claim 66, further comprising: (Claim 68) communicating a control signal to the tracker that causes the tracker to adjust the light signal emitted from the active marker corresponding to the blob based on the determined position of the active marker. comparing the determined position of the active marker to a previously determined position of the active marker to determine a change in distance between the active marker and the localizer camera; communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the change in distance; and 68. The method of claim 67, comprising: (Claim 69) communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the change in distance; determining that the change in distance indicates an increase in the distance between the active marker and the localizer camera; in response to determining that the change in distance indicates an increase in the distance between the active marker and the localizer camera, communicating a control signal to the tracker causing the tracker to increase an intensity and / or duration of the optical signal emitted from the active marker; 69. The method of claim 68, comprising: (Claim 70) 1. A method for optimizing tracking of targets within a surgical workspace by a navigation system including: a first tracker positioned relative to a first target within a surgical workspace, the first tracker having active markers of predefined geometry for tracking a pose of the first tracker within the surgical workspace; a second tracker positioned relative to a second target within the surgical workspace, the second tracker having active markers of predefined geometry for tracking a pose of the second tracker within the surgical workspace; a localizer camera configured to cooperate with the first and second trackers to generate image data indicative of a first blob for each of the active markers of the first tracker generated from optical signals emitted from the active markers, and a second blob for each of the active markers of the second tracker generated from optical signals emitted from the active markers; and a controller communicatively coupled to the first and second trackers and the localizer camera, repelling the first and second trackers relative to the first and second targets within the surgical workspace; the localizer camera generating the image data indicative of a first blob for each of the active markers of the first tracker generated from optical signals emitted from the active markers and a second blob for each of the active markers of the second tracker generated from optical signals emitted from the active markers; the controller obtaining characteristics of each of the first and second blobs; the controller comparing the obtained characteristic to a first optimum characteristic specific to the first tracker and a second optimum characteristic specific to the second tracker, the second optimum characteristic being different from the first optimum characteristic; based on the comparison, the controller assigning the first blob to the first tracker and the second blob to the second tracker; The method comprising: (Claim 71) 1. A method for optimizing tracking of a target within a surgical workspace by a navigation system including: a tracker positioned relative to the target, the tracker having active markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera configured to cooperate with the tracker to generate image data indicative of blobs of each of the active markers generated from optical signals emitted from the active markers; and a controller communicatively coupled to the tracker and the localizer camera, positioning the tracker relative to the target within the surgical workspace; generating, by the localizer camera, the image data indicative of each blob of the active markers generated from optical signals emitted from the active markers; the controller determining a position of the active marker of the tracker within the surgical workspace based on the image data; communicating at least one control signal to the tracker based on the determined positions of the active markers, the control signal causing the tracker to adjust the optical signal emitted from at least one of the active markers based on the determined positions; The method comprising: (Claim 72) 1. A method for optimizing tracking of a target within a surgical workspace by a navigation system including: a tracker positioned relative to a target, the tracker having passive markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit light signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of respective blobs of the passive markers generated from reflections by the passive markers of the light signals emitted from the light source; and a controller communicatively coupled to the localizer camera, positioning a tracker relative to the target within the surgical workspace; generating, by the localizer camera, the image data indicative of a blob of each of the passive markers generated from the reflection by the passive marker of the light signal emitted from the light source; the controller obtaining a characteristic of each blob; the controller comparing the obtained characteristic with an optimum characteristic; adjusting at least one optical parameter of the localizer camera based on the comparison; The method comprising: (Claim 73) 1. A method for tracking a landmark within a surgical workspace by a navigation system including: a first tracker positioned relative to a first landmark within a surgical workspace, the first tracker having passive markers of predefined geometry for tracking a pose of the first tracker within the surgical workspace; a second tracker positioned relative to a second landmark within the surgical workspace, the second tracker having passive markers of predefined geometry for tracking a pose of the second tracker within the surgical workspace; a localizer camera including a light source configured to emit light signals to illuminate the passive markers of the first and second trackers, the localizer camera configured to generate image data indicative of respective blobs of the passive markers of the first and second trackers generated from reflections of the light signals emitted from the light source off the passive markers; and a controller communicatively coupled to the localizer camera, positioning the first and second trackers relative to the first and second targets, respectively, within the surgical workspace; emitting a first optical signal from the light source, the first optical signal being characteristic of the first tracker; receiving, by the controller, image data generated by the localizer camera corresponding to the emitted first optical signal; the controller tracking a pose of the first tracker within the surgical workspace based on the received image data corresponding to the first optical signal; emitting from the light source a second optical signal having at least one characteristic that is characteristic of the second tracker and that differs from at least one corresponding characteristic of the first optical signal; receiving, by the controller, image data generated by the localizer camera corresponding to the emitted second optical signal; the controller tracking a pose of the second tracker within the surgical workspace based on the received image data corresponding to the second optical signal; The method comprising: (Claim 74) 1. A method for optimizing tracking of a target within a surgical workspace by a navigation system including: a tracker positioned relative to a target, the tracker having passive markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit light signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of respective blobs of the passive markers generated from reflections by the passive markers of the light signals emitted from the light source; and a controller communicatively coupled to the localizer camera, positioning the tracker relative to the target within the surgical workspace; emitting an optical signal having a varying characteristic from the light source; the controller receiving image data generated by the localizer camera for each of the emitted optical signals indicative of a blob of each of the passive markers generated from reflection of the emitted optical signals by the passive markers; for each instance of received image data, the controller obtaining a characteristic of each blob represented by the image data, the controller comparing the obtained characteristic to an optimum characteristic to determine which of the instances of received image data is closest to an optimum; in response to determining the instance of the received image data that is closest to optimal, the controller assigning to the tracker the characteristic of the optical signal that corresponds to the instance of the received image data; and the controller tracking a pose of the tracker within the surgical workspace based on the optical signal characteristic assigned to the tracker; The method comprising: (Claim 75) 1. A method for optimizing tracking of a target within a surgical workspace by a navigation system including: a tracker positioned relative to a target, the tracker having passive markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit light signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of respective blobs of the passive markers generated from reflections by the passive markers of the light signals emitted from the light source; and a controller communicatively coupled to the localizer camera, positioning the tracker relative to the target within the surgical workspace; generating image data indicative of each blob of the passive marker generated from the reflection by the passive marker of the light signal emitted from the light source; the controller determining the position of the passive marker of the tracker within the surgical workspace based on the image data; the controller adjusting at least one optical parameter of the localizer camera based on the determined position of the passive marker; The method comprising: (Claim 76) 1. A method for optimizing tracking of a target object within a surgical workspace by a navigation system, the navigation system including: a tracker positioned relative to the target object, the tracker having passive markers of predefined geometry that can be manually repositioned to track a pose of the tracker within the surgical workspace; a localizer camera including a light source configured to emit light signals to illuminate the passive markers, the localizer camera configured to generate image data indicative of each blob of the passive markers generated from reflections by the passive markers of the light signals emitted from the light source; and a controller communicatively coupled to the localizer camera; positioning the tracker relative to the target within the surgical workspace; generating, by the localizer camera, the image data indicative of a blob of each of the passive markers generated from the reflection by the passive marker of the light signal emitted from the light source; the controller obtaining a characteristic of each blob; the controller comparing the obtained characteristic with an optimum characteristic; the controller determining and displaying guidance for repositioning the passive marker of the tracker based on the comparison; and The method comprising:

Claims

1. 1. A navigation system for optimizing tracking of a target within a surgical workspace, comprising: a tracker positioned relative to the target, the tracker having active markers of predefined geometry for tracking a pose of the tracker within the surgical workspace; a localizer camera in cooperation with the tracker to generate image data indicative of each blob of the active markers generated from optical signals emitted from the active markers; a controller communicatively connected to the tracker and the localizer camera, assigning each of the blobs to the active marker corresponding to the blob; Get the characteristics of each blob, comparing the obtained characteristics with optimal characteristics; a controller that communicates at least one control signal to the tracker that causes the tracker to adjust the optical signal emitted from at least one of the active markers based on the comparison; and A navigation system comprising:

2. 10. The navigation system of claim 1, wherein the at least one control signal communicated to the tracker causes the tracker to adjust an intensity or a duration, or both, of the light signal emitted from the at least one of the active markers.

3. For each of the blobs, the controller: comparing the obtained characteristics of the blob with the optimal characteristics to determine if the blob is suboptimal; and in response to determining that the blob is not optimal based on the comparison, communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker corresponding to the blob.

2. The navigation system according to claim 1, wherein the navigation system is configured as follows:

4. The obtained characteristic of each blob exhibits a first value and the optimal characteristic exhibits a second value, and for each blob, the controller: comparing the first value indicated for the blob with the second value; communicating a control signal to the tracker that causes the tracker to reduce an intensity or duration, or both, of the light signal emitted from the active marker corresponding to the blob in response to the comparison indicating that the first value for the blob is greater than the second value; In response to the comparison indicating that the first value of the blob is less than the second value, communicating a control signal to the tracker that causes the tracker to increase the intensity or duration, or both, of the light signal emitted from the active marker corresponding to the blob. The navigation system according to claim 1 , configured to:

5. The navigation system of claim 4 , wherein the optimal blob intensity characteristic exhibits an intensity value that is greater than or equal to 75% and less than or equal to 95% of the localizer camera's full intensity value.

6. The navigation system of claim 1 , wherein the obtained characteristic is a blob intensity characteristic, and the optimal characteristic is an optimal blob intensity characteristic.

7. 5. The navigation system of claim 1, wherein the acquired property is a blob size property and the optimal property is an optimal blob size property, or the acquired property is a blob shape property and the optimal property is an optimal blob shape property.

8. The acquired characteristic is defined as an acquired first characteristic, the optimal characteristic is defined as a first optimal characteristic, and the controller: obtaining one or more second properties of one or more of the blobs; comparing the one or more obtained second characteristics to a second optimum characteristic; communicating at least one control signal to the tracker that causes the tracker to adjust the optical signal emitted from at least one of the one or more active markers corresponding to the one or more blobs based on the comparison of the one or more obtained second characteristics to the second optimal characteristic. The navigation system according to any one of claims 1 to 4, wherein the navigation system is configured as follows.

9. the image data includes first image data corresponding to a first optical sensor of the localizer camera and second image data corresponding to a second optical sensor of the localizer camera, each of the first and second image data representing a blob of each active marker generated from an optical signal emitted from the active marker, and the controller: identifying a first blob from the first image data and a second blob from the second image data, the first blob and the second blob corresponding to the same active marker; obtaining a first characteristic of the first blob and a second characteristic of the second blob; combining the obtained first feature and the obtained second feature to form a combined blob feature; comparing the combined blob characteristics to the optimal characteristics to determine if the combined blob characteristics are not optimal; and in response to determining, based on the comparison, that the combined blob characteristics are not optimal, communicating a control signal to the tracker that causes the tracker to adjust the optical signals emitted from the active markers corresponding to the first and second blobs.

3. The navigation system according to claim 1, wherein the navigation system is configured to:

10. The navigation system of claim 9 , wherein the first and second acquired properties are acquired intensity properties, and the optimal property is an optimal blob intensity property.

11. The combined blob characteristic is defined as a first combined blob characteristic, the optimal characteristic is defined as a first optimal characteristic, and the controller: obtaining a third property of the first blob and a fourth property of the second blob; combining the obtained third feature and the obtained fourth feature to form a second combined blob feature; comparing the second combined blob characteristic to a second optimal characteristic; communicating a control signal to the tracker that causes the tracker to adjust the optical signals emitted from the active markers corresponding to the first and second blobs based on the comparison of the second combined blob characteristic to the second optimal characteristic. The navigation system according to claim 9, configured to:

12. the target object is defined as a first target object, the blob is defined as a first blob, the tracker is defined as a first tracker, the acquired characteristic is defined as an acquired first characteristic, and the optimal characteristic is defined as a first optimal characteristic specific to the first tracker; and the surgical system further comprises a second tracker positioned relative to a second target within the surgical workspace, the second tracker having a predefined geometry of active markers for tracking a pose of the second tracker within the surgical workspace, the image data generated by the localizer camera including second blobs for each of the active markers of the second tracker generated from optical signals emitted from the active markers of the second tracker; and assigning each of the second blobs to the active marker of the second tracker corresponding to the second blob; obtaining a second characteristic of each second blob; comparing the obtained second characteristic to a second optimal characteristic that is specific to the second tracker and different from the first optimal characteristic; communicating at least one control signal to the second tracker that causes the second tracker to adjust the optical signal emitted from at least one of the active markers of the second tracker based on the comparison. The navigation system according to any one of claims 1 to 4, configured as follows:

13. 13. The navigation system of claim 12, wherein the controller is configured to assign the first blob to the active marker of the first tracker based on the first optimal characteristic, and / or assign the second blob to the active marker of the second tracker based on the second optimal characteristic.

14. For each of the first blobs, the controller: determining a difference between the obtained first characteristic of the first blob and the first optimum characteristic; determining whether the difference between the obtained first characteristic and the first optimal characteristic of the first blob is less than a threshold; In response to determining that the difference between the acquired first characteristic and the first optimal characteristic of the first blob is less than the threshold, determine that the first blob corresponds to the first tracker and assign the first blob to the active marker of the first tracker corresponding to the first blob. The navigation system according to claim 12, configured to:

15. 13. The navigation system of claim 12, wherein the predefined geometries of the active markers of the first tracker and the predefined geometries of the active markers of the second tracker are substantially equivalent.

16. The controller: determining a position of the active marker of the tracker within the surgical workspace based on the image data; communicating the at least one control signal to the tracker that causes the tracker to adjust the optical signal emitted from at least one of the active markers based on the determined positions of the active markers. The navigation system according to any one of claims 1 to 4, wherein the navigation system is configured as follows.

17. For each of the active markers, the controller: comparing the obtained characteristics of the blob corresponding to the active marker with the optimal characteristics to determine whether the blob corresponding to the active marker is not optimal; In response to determining that the blob corresponding to the active marker is not optimal, communicate a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the determined position of the active marker.

17. The navigation system according to claim 16, wherein the navigation system is configured as follows:

18. The controller: comparing the determined position of the active marker to a previously determined position of the active marker to determine a change in distance between the active marker and the localizer camera; communicating a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the change in distance.

20. The navigation system of claim 17, wherein the navigation system is configured to communicate a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the determined position of the active marker.

19. The controller determining whether the change in distance indicates an increase or a decrease in the distance between the active marker and the localizer camera; communicating a control signal to the tracker that causes the tracker to increase an intensity and / or duration of the light signal emitted from the active marker in response to the change in distance indicating an increase in the distance between the active marker and the localizer camera; communicating a control signal to the tracker that causes the tracker to reduce an intensity and / or duration of the optical signal emitted from the active marker in response to the change in distance indicating a decrease in the distance between the active marker and the localizer camera.

20. The navigation system of claim 18, wherein the navigation system is configured to communicate a control signal to the tracker that causes the tracker to adjust the optical signal emitted from the active marker based on the determined change in distance.

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