# US 2019/0377432 A1 · Mechanical optical pointer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0377432 A1 - Document ID: US20190377432A1 - Status: Published application - Kind: A1 - Application number: 16/547,125 - Filed: 2019-08-21 - Published: 2019-12-12 - Earliest claimed: 2016-10-14 - Assignees: Orthosoft Inc. - Applicants: ORTHOsoft, Inc. - Inventors: Emily Gogarty; Pierre Couture - Web page: https://patentgrep.com/patent/US20190377432A1 ## CPC - G06F 3/03545: {Pens or stylus} - A61B 34/20: Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis - G06F 3/0304: {Detection arrangements using opto-electronic means (constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042)} - G06F 3/0325: {using a plurality of light emitters or reflectors or a plurality of detectors forming a reference frame from which to derive the orientation of the object, e.g. by triangulation or on the basis of reference deformation in the picked up image} - A61B 90/39: {Markers, e.g. radio-opaque or breast lesions markers} - A61B 2034/2055: {Optical tracking systems} - A61B 2034/2068: {using pointers, e.g. pointers having reference marks for determining coordinates of body points} - A61B 2090/0811: {for the position of a particular part of an instrument with respect to the rest of the instrument, e.g. position of the anvil of a stapling instrument} - A61B 2090/371: {with simultaneous use of two cameras} - A61B 2090/3983: {Reference marker arrangements for use with image guided surgery} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract Embodiments of a system and method for digitizing locations within a coordinate system are generally described herein. A device may include a sleeve including a sleeve tracking marker and a tracked probe portion including an array of tracking markers and a probe tip. Movement of the probe tip relative to the sleeve between at least a first position and a second position may be monitored by tracking the sleeve tracking marker relative to at least one tracking marker of the array of tracking markers. ## Claims ### Claim 1 A pointer device for digitizing locations within a coordinate system, the pointer device comprising: a first portion including a distal end and a proximal end, the first portion including a first tracking marker; and a tracked probe including a proximal end configured to support an array of tracking markers, a distal end including a probe tip, and an intermediate section adapted to slidably engage the first portion, wherein the intermediate section extends along a longitudinal axis from the distal end to the proximal end; wherein movement of the probe tip relative to the first portion between at least a first position and a second position can be monitored by tracking the first tracking marker relative to an intermediate point between the array of tracking markers, wherein a distance between the first tracking marker and the intermediate point is shorter along the longitudinal axis when the probe tip is at the second position than when the probe tip is at the first position, wherein movement of the probe tip into the second position indicates a location to be digitized at the probe tip through transgressing a threshold distance between the first tracking marker and the intermediate point. ### Claim 2 (depends on 1) The pointer device of claim 1, wherein at least a portion of the intermediate section is partially radially surrounded by the first portion. ### Claim 3 (depends on 1) The pointer device of claim 1, wherein at least a portion of the intermediate section is fully radially surrounded by the first portion. ### Claim 4 (depends on 1) The pointer device of claim 1, further comprising an elastic resistance member configured to provide resistance to movement of the first portion in a direction along the longitudinal axis. ### Claim 5 (depends on 4) The pointer device of claim 4, wherein the elastic resistance member is a spring, and wherein the first portion is configured to receive a force that causes the elastic resistance member to compress and decreases a distance between the first tracking marker and the intermediate point. ### Claim 6 (depends on 5) The pointer device of claim 5, wherein the first portion includes a trigger mechanism to receive the force. ### Claim 7 (depends on 1) The pointer device of claim 1, wherein the first portion is configured to be removed and replaced between each surgical procedure. ### Claim 8 A method for tracking objects in a coordinate system, the method comprising: tracking, using an optical navigation system, a pointer device including a first tracking marker mounted on a first portion of the pointer device and an array of tracking markers mounted on a tracked probe frame portion of the pointer device, wherein the first tracking marker is configured to move relative to the tracked probe frame portion; detecting, using the optical navigation system, that a distance from the first tracking marker to at least one tracking marker of the array of tracking markers has changed; determining whether the distance from the first tracking marker to the at least one tracking marker has transgressed a threshold, wherein determining whether the distance has transgressed the threshold includes determining an intermediate point on the tracked probe frame portion, and determining a distance from the intermediate point to the first tracking marker; and registering, in response to determining that the threshold has been transgressed, one or more locations of a probe tip of the pointer device. ### Claim 9 (depends on 8) The method of claim 8, wherein determining the intermediate point includes triangulating distances from at least three tracking markers of the array of tracking markers. ### Claim 10 (depends on 8) The method of claim 8, wherein detecting that the distance from the first tracking marker to at least one tracking marker of the array of tracking markers has changed includes detecting that the distance from the first tracking marker to all tracking markers of the array of tracking markers has changed. ### Claim 11 (depends on 8) The method of claim 8, wherein determining whether the distance from the first tracking marker to the at least one tracking marker has transgressed the threshold includes determining that the distance has fallen below the threshold due to movement of the first portion of the pointer device. ### Claim 12 (depends on 8) The method of claim 8, further comprising preventing registration, in response to determining that the threshold has not been transgressed, of locations of the probe tip of the pointer device. ### Claim 13 (depends on 8) The method of claim 8, further comprising: determining that the distance has transgressed the threshold for a period of time; and grouping the one or more locations of the probe tip of the pointer device registered during the period of time. ### Claim 14 (depends on 8) The method of claim 8, further comprising: determining an initial distance from the first tracking marker to each of the array of tracking markers, the initial distance based on an installed position of the first portion of the pointer device. ### Claim 15 (depends on 8) The method of claim 8, wherein the first tracking marker is mounted on a sleeve having a distal end, a proximal end, and a bore along a longitudinal axis between the distal end and the proximal end. ### Claim 16 A system for tracking objects in a coordinate system, the system comprising: a pointer device including a first tracking marker, an array of tracking markers mounted on a tracked probe frame portion of the pointer device, and a probe tip, wherein the first tracking marker is configured to be movable relative to the tracked probe frame portion; and an optical navigation system including two or more cameras, an infrared light source, and a processor, the processor to: receive information from the two or more cameras; determine whether a distance from the first tracking marker to at least one tracking marker of the array of tracking markers has transgressed a threshold, wherein determining whether the distance has transgressed the threshold includes determining an intermediate point on the tracked probe frame portion, and determining a distance from the intermediate point to the first tracking marker; and register, in response to determining that the threshold has been transgressed, one or more locations of the probe tip of the pointer device. ### Claim 17 (depends on 16) The system of claim 16, wherein determining the intermediate point includes triangulating distances from at least three tracking markers of the array of tracking markers. ### Claim 18 (depends on 16) The system of claim 16, the processor further to: determine an initial distance from the first tracking marker to each of the array of tracking markers, the initial distance based on an installed position of the first portion of the pointer device. ### Claim 19 (depends on 16) The system of claim 16, wherein the first tracking marker is a sleeve tracking marker mounted on a sleeve. ### Claim 20 (depends on 19) The system of claim 19, wherein the sleeve includes a trigger mechanism configured to receive a force that causes an elastic resistance member to compress and decreases a distance between the sleeve tracking marker and the at least one tracking marker of the array of tracking markers.