METHODS AND DEVICES FOR TABLE POSE TRACKING USING FIDUCIAL MARKERS
20210251701 · 2021-08-19
Inventors
- Patrick O'Grady (Alameda, CA, US)
- Christopher R. Burns (San Jose, CA, US)
- Simon P. DiMaio (San Carlos, CA)
- Jason Hemphill (Los Gatos, CA, US)
- Brian D. Hoffman (Mountain View, CA)
- Rodney Vance (Willow Spring, NC, US)
- Tao Zhao (Sunnyvale, CA)
Cpc classification
A61B2034/2068
HUMAN NECESSITIES
A61B34/20
HUMAN NECESSITIES
A61B2090/3983
HUMAN NECESSITIES
A61B90/90
HUMAN NECESSITIES
A61G2205/60
HUMAN NECESSITIES
A61B34/70
HUMAN NECESSITIES
International classification
A61B34/20
HUMAN NECESSITIES
A61B34/00
HUMAN NECESSITIES
A61B90/90
HUMAN NECESSITIES
Abstract
A method of estimating a pose of a surgical table comprises reading one or more fiducial markers on a base of the surgical table with a camera mounted to a manipulator assembly adjacent the surgical table. The surgical table includes a substrate and a support structure supporting the substrate. The substrate has a support surface. The support structure is movable such that the support surface of the substrate is positionable along one or more degrees of freedom (DOF).
Claims
1-15. (canceled)
16. A method of estimating a pose of a surgical table comprising: reading one or more fiducial markers on a base of the surgical table with a camera mounted to a manipulator assembly adjacent the surgical table, the surgical table including a substrate and a support structure supporting the substrate, the substrate having a support surface, wherein the support structure is movable such that the support surface of the substrate is positionable along one or more degrees of freedom (DOF).
17. The method of claim 16, further comprising: affixing the one or more fiducial markers to the surgical table or forming the one or more fiducial markers in the surgical table at select locations in a particular orientation relative to the surgical table, wherein forming the one or more fiducial markers in the surgical table comprises etching, engraving, and/or embossing the one or more fiducial markers in the surgical table.
18. The method of claim 16, further comprising localizing the surgical table relative to the manipulator assembly on a common plane based on the reading of the one or more fiducial markers.
19. The method of claim 18, wherein the common plane is a ground plane on which the surgical table and the manipulator assembly are disposed.
20. The method of claim 18, further comprising: translating a 6 DOF 3D pose of the surgical table to a 3DOF 2D pose on the common plane; or estimating a 3D pose of the surgical table relative to the manipulator assembly based on localization of the surgical table relative to the manipulator assembly on the common plane.
21. The method of claim 18, wherein the one or more fiducial markers are disposed at multiple locations on the surgical table and wherein reading the one or more fiducial markers comprises reading at least one of the one or more fiducial markers.
22. The method of claim 18, wherein reading the one or more fiducial markers comprises reading a single fiducial marker of the one or more fiducial markers and wherein localization of the surgical table is based on the reading of the single fiducial marker.
23. The method of claim 16, further comprising: extracting locations of the surgical table within a visual image obtained with the camera and providing a representation or indication of the surgical table with respect to a camera view of the camera.
24. The method of claim 16, further comprising: identifying a type, model, or make of the surgical table based on reading of the one or more fiducial markers, and checking a compatibility aspect between the surgical table and the manipulator assembly or granting permissions for use of the manipulator assembly with the surgical table.
25. A tele-surgical system comprising: a manipulator assembly; a surgical table disposed in proximity to the manipulator assembly, the surgical table having one or more fiducial markers on a base of the surgical table, the surgical table further including a substrate and a support structure supporting the substrate, the substrate having a support surface, wherein the support structure is movable such that the support surface is positionable along one or more degrees of freedom (DOF); a camera mounted to the manipulator assembly that is configured to read the one or more fiducial markers of the surgical table when the surgical table is positioned within close proximity of the manipulator assembly; and a processor configured to read the one or more fiducial markers using the camera.
26. The system of claim 25, wherein the one or more fiducial markers include a barcode, an RFID tag, a light, or any combination thereof.
27. The system of claim 25, wherein the one or more fiducial markers are fixedly attached or formed in select portions and locations in a particular orientation relative to the surgical table such that a pose of the surgical table relative to a ground plane is determinable from reading of at least one of the one or more fiducial markers.
28. The system of claim 25, wherein the processor is further configured to: localize the surgical table relative to the manipulator assembly on a common plane based on the reading of the one or more fiducial markers.
29. The system of claim 28, wherein the surgical table is positionable along 6 DOF and the processor is further configured to: translate a 6 DOF 3D pose of the surgical table to a 3DOF 2D pose on the common plane.
30. The system of claim 28, wherein the surgical table is positionable along 6 DOF and the processor is further configured to: estimate a 3D pose of the surgical table relative to the manipulator assembly based on localization of the base of the surgical table relative to the manipulator assembly on the common plane.
31. The system of claim 25, wherein the processor is further configured to: extract locations of the surgical table within a visual image obtained with the camera, and provide a representation or indication of the surgical table with respect to a camera view of the camera.
32. The system of claim 25, wherein the processor is further configured to: identify a type, model, or make of surgical table based on reading of the one or more fiducial markers, and check a compatibility aspect between the surgical table and the manipulator assembly and/or granting permissions for use of the manipulator assembly with the surgical table.
33. A surgical table, comprising: a base; a substrate having a patient support surface; a support structure supporting the substrate, the support structure being movable such that the patient support surface is positionable along one or more DOF; and one or more fiducial markers disposed on the base of the surgical table at select locations and/or orientations such that the one or more fiducial markers are readable using a camera when the surgical table is positioned and being communicatively coupled with a tele-surgical system having a manipulator assembly, wherein the camera has a known position relative to the manipulator assembly.
34. The surgical table of claim 33, wherein the select locations and/or orientations are pre-determined such that the pose of the surgical table is determinable by reading of at least one of the one or more fiducial markers.
35. The surgical table of claim 33, wherein the support structure is configured such that the substrate is positionable along 6 DOF.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
[0046] In the following description, various embodiments of the present invention will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to one skilled in the art that the present invention may be practiced without the specific details. Furthermore, well-known features may be omitted or simplified in order not to obscure the embodiments being described.
[0047] The kinematic linkage structures and control systems described herein are particularly beneficial in helping system users to arrange the tele-surgical manipulator structure on a particular patient. Along with actively driven manipulators used to interact with tissues and the like during treatment, tele-surgical systems may have one or more kinematic linkage systems that are configured to support and help align the manipulator structure with the surgical work site. While the high degree of configurability of these kinematic systems offer many advantages and advanced features, it can be difficult to locate a location of a manipulator feature of the manipulator assembly with respect to a separate component, such as a surgical table, particularly when the surgical table is separately positionable from the manipulator assembly. Since it is often useful to position a patient in various orientations or alignments in preparation for or during a procedure, it is desirable if the manipulator assembly can be localized with the surgical table either during initial set-up, or during a procedure, so that a position and/or orientation of the surgical table relative to the manipulator assembly can be determined and potentially utilized in calculated manipulator movements or surgical table movements (either automatic or user driven). Such localization and pose estimations methods allow further utilization of various calculated movement of the manipulators described in related applications, including but not limited to various null-space movement and collision avoidance movements, and may further be used to determine a position and/or orientation of the surgical table to any manipulator or associated component of the manipulator assembly. In addition, pose estimation may be used in accordance with various other features, such as any of those described in U.S. application Ser. No. 14/101,769 filed on Dec. 10, 2013, entitled, “Collision Avoidance During Controlled Movement of Image Capturing Device and Manipulatable Device Movable Arms,” which is incorporated herein by reference in its entirety for all purposes, or any of the references incorporated by reference therein. The systems, devices and methods described herein, while applied to these particular surgical systems, may be used with various different types of manipulator systems, in accordance with the aspects of the invention described herein.
[0048] Minimally Invasive Tele-surgery
[0049] Referring now to the drawings, in which like reference numerals represent like parts throughout the several views,
[0050]
[0051] The Surgeon's Console 16 is usually located in the same room as the patient so that the Surgeon may directly monitor the procedure, be physically present if necessary, and speak to an Assistant directly rather than over the telephone or other communication medium. However, the Surgeon can be located in a different room, a completely different building, or other remote location from the Patient allowing for remote surgical procedures.
[0052]
[0053]
[0054] Processor 58 will typically include a combination of hardware and software, with the software comprising tangible media embodying computer readable code instructions for performing the method steps of the control functionally described herein. The hardware typically includes one or more data processing boards, which may be co-located but will often have components distributed among the manipulator structures described herein. The software will often comprise a non-volatile media, and could also comprise a monolithic code but will more typically comprise a number of subroutines, optionally running in any of a wide variety of distributed data processing architectures.
[0055]
[0056] Surgical tools 26 are inserted into the patient by inserting a tubular cannula 64 through a minimally invasive access aperture such as an incision, natural orifice, percutaneous penetration, or the like. Cannula 64 is mounted to the manipulator arm and the shaft of surgical tool 26 passes through the lumen of the cannula. The manipulator arm may transmit signals indicating that the cannula has been mounted thereon.
[0057] Tele-Surgical Systems and Modular Manipulator Supports
[0058]
[0059] In many embodiments, the mounting base 72 is movable and floor supported, thereby enabling selective repositioning of the overall surgery system 70, for example, within an operating room. The mounting base 72 can include a steerable wheel assembly and/or any other suitable support features that provide for both selective repositioning as well as selectively preventing movement of the mounting base 72 from a selected position. The mounting base 72 can also have other suitable configurations, for example, a ceiling mount, fixed floor/pedestal mount, a wall mount, or an interface configured for being supported by any other suitable mounting surface.
[0060] The support linkage 74 is operable to selectively position and/or orient the orienting platform 76 relative to the mounting base 72. The support linkage 74 includes a column base 86, a translatable column member 88, a shoulder joint 90, a boom base member 92, a boom first stage member 94, a boom second stage member 96, and a wrist joint 98. The column base 86 is fixedly attached to the mounting base 72. The translatable column member 88 is slideably coupled to the column base 86 for translation relative to column base 86. In many embodiments, the translatable column member 88 translates relative to the column base 86 along a vertically oriented axis. The boom base member 92 is rotationally coupled to the translatable column member 88 by the shoulder joint 90. The shoulder joint 90 is operable to selectively orient the boom base member 92 in a horizontal plane relative to the translatable column member 88, which has a fixed angular orientation relative to the column base 86 and the mounting base 72. The boom first stage member 94 is selectively translatable relative to the boom base member 92 in a horizontal direction, which in many embodiments is aligned with both the boom base member 92 and the boom first stage member 94. The boom second stage member 96 is likewise selectively translatable relative to the boom first stage member 94 in a horizontal direction, which in many embodiments is aligned with the boom first stage member 94 and the boom second stage member 96. Accordingly, the support linkage 74 is operable to selectively set the distance between the shoulder joint 90 and the distal end of the boom second stage member 96. The wrist joint 98 rotationally couples the distal end of the boom second stage member 96 to the orienting platform 76. The wrist joint 98 is operable to selectively set the angular orientation of the orienting platform 76 relative to the mounting base 72.
[0061] Each of the set-up linkages 78, 80 is operable to selectively position and/or orient the associated manipulator 82 relative to the orienting platform 76. Each of the set-up linkages 78, 80 includes a set-up linkage base link 100, a set-up linkage extension link 102, a set-up linkage parallelogram linkage portion 104, a set-up linkage vertical link 106, a second set-up linkage joint 108, and a manipulator support link 110. In each of the set-up linkage base links 100 of the outer set-up linkages 78 can be selectively oriented relative to the orienting platform 76 via the operation of the a first set-up linkage joint 84. In the embodiment shown, each of the set-up linkage base links 100 of the inner set-up linkages 80 is fixedly attached to the orienting platform 76. Each of the inner set-up linkages 80 can also be rotationally attached to the orienting platform 76 similar to the outer set-up linkages via an additional first set-up linkage joints 84. Each of the set-up linkage extension links 102 is translatable relative to the associated set-up linkage base link 100 in a horizontal direction, which in many embodiments is aligned with the associated set-up linkage base link and the set-up linkage extension link 102. Each of the set-up linkage parallelogram linkage portions 104 configured and operable to selectively translate the set-up linkage vertical link 106 in a vertical direction while keeping the set-up linkage vertical link 106 vertically oriented. In example embodiments, each of the set-up linkage parallelogram linkage portions 104 includes a first parallelogram joint 112, a coupling link 114, and a second parallelogram 116. The first parallelogram joint 112 rotationally couples the coupling link 114 to the set-up linkage extension link 102. The second parallelogram joint 116 rotationally couples the set-up linkage vertical link 106 to the coupling link 114. The first parallelogram joint 112 is rotationally tied to the second parallelogram joint 116 such that rotation of the coupling link 114 relative to the set-up linkage extension link 102 is matched by a counteracting rotation of the set-up linkage vertical link 106 relative to the coupling link 114 so as to maintain the set-up linkage vertical link 106 vertically oriented while the set-up linkage vertical link 106 is selectively translated vertically. The second set-up linkage joint 108 is operable to selectively orient the manipulator support link 110 relative to the set-up linkage vertical link 106, thereby selectively orienting the associated attached manipulator 82 relative to the set-up linkage vertical link 106.
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[0063] The support linkage 122 is operable to selectively position and/or orient the orienting platform 124 relative to the mounting base 72. The support linkage 122 includes the column base 86, the translatable column member 88, the shoulder joint 90, the boom base member 92, the boom first stage member 94, and the wrist joint 98. The support linkage 122 is operable to selectively set the distance between the shoulder joint 90 and the distal end of the boom first stage member 94. The wrist joint 98 rotationally couples the distal end of the boom first stage member 94 to the orienting platform 124. The wrist joint 98 is operable to selectively set the angular orientation of the orienting platform 124 relative to the mounting base 72.
[0064] Each of the set-up linkages 126 is operable to selectively position and/or orient the associated manipulator 82 relative to the orienting platform 124. Each of the set-up linkages 126 includes the set-up linkage base link 100, the set-up linkage extension link 102, the set-up linkage vertical link 106, the second set-up linkage joint 108, a tornado mechanism support link 128, and a tornado mechanism 130. Each of the set-up linkage base links 100 of the set-up linkages 126 can be selectively oriented relative to the orienting platform 124 via the operation of the associated first set-up linkage joint 84. Each of the set-up linkage vertical links 106 is selectively translatable in a vertical direction relative to the associated set-up linkage extension link 102. The second set-up linkage joint 108 is operable to selectively orient the tornado mechanism support link 128 relative to the set-up linkage vertical link 106
[0065] Each of the tornado mechanisms 130 includes a tornado joint 132, a coupling link 134, and a manipulator support 136. The coupling link 134 fixedly couples the manipulator support 136 to the tornado joint 132. The tornado joint 130 is operable to rotate the manipulator support 136 relative to the tornado mechanism support link 128 around a tornado axis 136. The tornado mechanism 128 is configured to position and orient the manipulator support 134 such that the remote center of manipulation (RC) of the manipulator 82 is intersected by the tornado axis 136. Accordingly, operation of the tornado joint 132 can be used to reorient the associated manipulator 82 relative to the patient without moving the associated remote center of manipulation (RC) relative to the patient.
[0066]
[0067] The support linkage 122 is configured to selectively position and orient the orienting platform 124 relative to the mounting base 72 via relative movement between links of the support linkage 122 along multiple set-up structure axes. The translatable column member 88 is selectively repositionable relative to the column base 86 along a first set-up structure (SUS) axis 142, which is vertically oriented in many embodiments. The shoulder joint 90 is operable to selectively orient the boom base member 92 relative to the translatable column member 88 around a second SUS axis 144, which is vertically oriented in many embodiments. The boom first stage member 94 is selectively repositionable relative to the boom base member 92 along a third SUS axis 146, which is horizontally oriented in many embodiments. The wrist joint 98 is operable to selectively orient the orienting platform 124 relative to the boom first stage member 94 around a fourth SUS axis 148, which is vertically oriented in many embodiments.
[0068] Each of the set-up linkages 126 is configured to selectively position and orient the associated manipulator 82 relative to the orienting platform 124 via relative movement between links of the set-up linkage 126 along multiple set-up joint (SUJ) axes. Each of the first set-up linkage joint 84 is operable to selectively orient the associated set-up linkage base link 100 relative to the orienting platform 124 around a first SUJ axis 150, which in many embodiments is vertically oriented. Each of the set-up linkage extension links 102 can be selectively repositioned relative to the associated set-up linkage base link 10 along a second SUJ axis 152, which is horizontally oriented in many embodiments. Each of the set-up linkage vertical links 106 can be selectively repositioned relative to the associated set-up linkage extension link 102 along a third SUJ axis 154, which is vertically oriented in many embodiments. Each of the second set-up linkage joints 108 is operable to selectively orient the tornado mechanism support link 128 relative to the set-up linkage vertical link 106 around the third SUJ axis 154. Each of the tornado joints 132 is operable to rotate the associated manipulator 82 around the associated tornado axis 138.
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[0070] In use, it will often be desirable for a surgical assistant, surgeon, technical support, or other user to configure some or all of the linkages of tele-surgical system 140 for surgery, including the set-up structure linkage, the set-up joints, and/or each of the manipulators. Included among the task in configuring these linkages will be positioning the orienting platform 124 relative to first stage member 94 about vertical fourth SUS axis 148 of wrist joint 98. A joint drive motor 121 and/or brake system 123 is coupled to wrist joint 98, with one exemplary embodiment including both a drive 121 and brake 123. Additionally, a joint sensor system will typically sense an angular configuration or position of wrist joint 98.
[0071] An exemplary user interface, system, and method for manually configuring the system for use will be described herein with reference to manual articulation of orienting platform 124 by articulation of wrist joint 98 about fourth SUS axis 148, as schematically illustrated by arrow 127. It should be understood that alternative embodiments may be employed to articulate one or more alternative joints of the overall kinematic system, including one or more alternative joints of the set-up structure, one or more of the set-up joints, or one or more of the joints of the manipulators linkages. Use of the exemplary embodiment for articulating the motorized wrist joint embodiments may allow a user to efficiently position manipulators 82. The manual articulation of wrist joint 98 as described herein can improve speed and ease of use while manually docking manipulators 82 to their associated cannulas 64, as shown in
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[0075] The surgical table 200 includes the surgical table patient support surface 210 supported by a support column 204 extending vertically from a support base 202. Typically, the surgical table 200 is positionable along at least one degree of freedom, preferably along multiple degrees of freedom, and even more preferably along six degrees of freedom. As shown in
[0076] While the high degree of configurability of such a surgical table provides many advantages and versatility in positioning the patient, this configurability can further pose additional challenges in calculating movements of the manipulator arms and associated tools. For example, when the surgical table is positioned at an incline, certain movements of the tool or an associated manipulator supporting the tool may collide with the patient support surface. While various methods may be used to avoid such collisions, it is particularly useful if the position of the surgical table relative the manipulators of the Patient Side Cart is determined so that movements of the manipulators can be calculated to account for the position of the surgical table and/or to compensate for movement and/or repositioning of the surgical table during a procedure. To allow such a determination, methods and systems in accordance with aspects of the present invention provides a table pose estimate of the surgical table relative the Patient Side Cart so that a spatial relationship between the surgical table and Patient Side Cart can be determined and utilized in various calculated movements as needed. In another aspect, methods of the invention may be used to identify a surgical table for use with a particular manipulator assembly and/or establish communication with the surgical table to allow various calculated coordinated movements therebetween.
[0077] In one aspect, the relative pose of the operating table and the robot is needed since both the robot and the table is articulated object with multiple degrees of freedom. By determining the pose of the surgical table relative the manipulator assembly, various advantageous features can be realized by performing coordinated movements between the surgical table and the manipulator assembly. Since the DOFs of each of the surgical table and the manipulator assembly can be sensed through sensors, determination of a relative pose between any two parts of the component is sufficient. In one aspect, the methods determine position and orientation of a base of the surgical table, which allows the system to determine relative positions of the various components of each of the surgical table and the manipulator assembly relative to one another.
[0078] In certain embodiments, the table is controlled to rotate around the centroid of the ports in order to minimize the overall motion of the ports (isocenter concept). This is useful for various features and in particular, “port dragging.” If the port dragging results in too much force to patient's body wall active driving of the robot arms is needed to follow the motion of the table. The knowledge of the patient placement (through table placement) with respect to the robot helps the robot to optimize its control to avoid potential collision with the patient. There are multiple ways of measure a relative pose between two objects. There are several constraints that make us to choose optical solution as a preferred method.
[0079] In certain aspect, methods of the present invention provide various advantageous features over conventional manipulator systems. In one aspect, the methods include determining 6 DOF 3D pose (translation and rotation) between the surgical robot and the operating table using a camera mounted on the robot and fiducial markers on the external surface of the operating table. The 3D pose becomes 3 DOF 2D pose on the ground plane both components are assumed to be located on a common ground plane. The fiducial marker can be sub-divided into components that can be independently recognized and identified, or a subset of the fiducial marker can be recognized and identified against the entire marker. The fiducial marker embeds redundancy such as check sum or Reed-Solomon error checking and correction scheme. In certain aspects, the fiducial marker contains visual features that can be accurately localized in an image for use in pose estimation. The fiducial marker may consist of multiple unique 2D barcodes which can be data matrix codes. The fiducial markers may consist of multiple unique 1D barcodes with the bars in vertical orientation. In another aspect, the fiducial marker may consist of multiple single point light emitting devices in a blinking pattern (e.g. Morse code), and may also be combined with color to form unique identifiers of the devices.
[0080] It is appreciated that embodiments may include one or more markers that include aspects of any of the fiducial markers described herein. For example, a table may include one or more markers that include 1D, 2D or 3D barcodes in combination with light emitting device, RFID tags, or any aspect described herein. In addition, such markers may be included on various differing locations on the table so as to allow sensing of the respective markers by one or more corresponding sensors associated with one or more other external devices. In is further appreciated that the methods of localizing a table relative a manipulator assembly apply to non-surgical applications, for example in simulation, testing and/or setup of tele-surgical system, as well as in various other applications, including but not limited to various industrial robotic applications.
[0081] In certain other aspects, the fiducial marker can be used to identify a type, model, serial number of a surgical table being used with a particular manipulator assembly. The marker pattern may include a unique identifier for each operating table. The software can be configured to detect the fiducial markers in the image, extracts the locations of the visual features. The unique identifications of the fiducial markers allowed correspondence to be established by using of known 3D locations of the markers. The corresponding 3D and 2D observations are used to compute the 3D pose of the operating table with respect to the camera. In certain embodiments, multiple surgical robots or disjoint surgical robot components each equipped with a camera. In one aspect, the relative poses are computed by having the cameras to observe a common operating table with fiducial markers on its external surface. It is appreciated that the cameras are not required to have a common view. Among the many advantages of these methods, is that, in many embodiments, a physical connection between the manipulator assembly and the operating room table is not required for localization. As long as line of sight is maintained between the sensor associated with the manipulator and the at least one marker pattern of the surgical table, localization is not affected by the environment (e.g. EMI). In some aspects, once localization is established line of sight need not be maintained unless the table is repositioned. In another aspect, a movable support structure which the table top is positioned wirelessly communicates with the manipulator assembly such that any changes in table pose after localization are accounted for without requiring the table be re-localized using the one or more fiducial markers.
[0082]
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[0084] In one aspect, the marker and sensor are configured according to various range of motion considerations, including any or all of: [0085] Sensor module performs pose estimation when the distance between the sensor the front of the object is in the range from 5 cm to 100 cm. It should be noted that sensor module may be configured to work when the object is either in the center or off the center of the field of the view of the sensor. [0086] Sensor module working in extended range. Sensor module is configured to perform pose estimation when the object is of any angle to the sensor.
[0087] In one aspect, the marker and sensor are configured according to various illumination considerations including any or all of: [0088] The environment can be from very low light (5 lux) to bright operating theatre lighting (2000 lux). [0089] Extra illumination, if needed, can be located close to the sensor, possibly near-IR. [0090] The extra illumination may be configured to activate, as needed, when performing image data collection.
[0091] Operating Room Table Pose Estimation
[0092] In one aspect, one distinguishing feature of manipulator assemblies that benefit from these methods is the ability of moving the patient table during the procedure without undocking and re-docking. To accommodate intra-operative table motion, an operating room (OR) table that pivots around a point in 3D can be used. In some embodiments, the pivoting point coincides with the centroid of all the ports so that the overall displacement of all ports is minimized. This may require that the relative pose of the Patient Side Cart (PSC) and the OR table to be known. Since on both the PSC and the OR table the full kinematics information is available, the pose between any part on PSC and any part on OR table is sufficient. These method address various problems that may be associated with conventional marker reading techniques or localization methods, including any or all of: no mechanical link between OR table and PSC; no cable between OR table and PSC. These methods address difficulties associated with OR environments, including low illumination associated with robotic surgery which does not require light, standard operating rooms that are particularly bright, possible interference, cautery noise, the presence of IR links and/or RF links.
[0093] In one aspect, the markers and sensor are configured to provide sufficient accuracy. In some embodiments, the accuracy requirement is that the center of the table is measured within +/−1 Omm, this requirement is largely derived from the size of a cannula. Even when the error is zero, since the manipulators have some displacement at each port (e.g. pivoting point is the centroid of all ports); thus, a bigger error may be tolerated.
[0094] In another aspect, the sensor module needs to fit in the allocated space in the PSC base. In some embodiments, the space allotted for the sensor module in the base of the manipulator assembly is about 3″×3″×5″ while the distance from the optical window to the most front surface is about 2″.
[0095] In another aspect, the sensor and marker configuration is configured to be read so as to allow sufficient working distance between the surgical table and the manipulator assembly, which allows a range of positions and/or orientations of the surgical table. For example, the marker and sensor can be configured such that the marker can be read within a horizontal field of view of close to 60 degrees and the working distance for reading the marker may be between an inch to 2 feet or more. The table may also include markers on each side of the support base so that the table can rotated completely, as may be needed for a particular procedure.
[0096] In certain aspects, the marker and sensor may be configured to track the one or more markers with any or all of electro-magnetic tracking, optical tracking, laser based, shape sensor, ultrasonic means, or any combination thereof. Due to drawbacks associated with certain of these approaches, however, methods typically utilize optical tracking of markers to perform pose estimate as described herein. One benefit is optical tracking is that it is not affected by invisible interference (e.g. electromagnetic (EM) interference). A down side is the line of sight issue since the fiducial markers need to be visible. However, different to EM interference, this is much easier for the user to understand to correct (e.g., moving away a trash can between the camera and the marker). The basic principal of the optical tracking is to compute the pose of an object or fiducial marker with known geometry by its image observations. In another aspect, a monocular or a pair of stereo cameras can be used.
[0097] In one aspect, multiple passive retro-reflective balls or active blinking LEDs forming a geometrically unique configuration. In one aspect the fiducial marker comprise 2D barcodes. Any 2D barcode should be able to be used as marker as long as the reader can provide the image coordinates of the some reference points (ideally >=4) of the barcode. In another aspect, active point markers may be used. Multiple active point markers (e.g. LEDs) are placed around the peripheral of the table base. Their blinking patterns are unique to make them easily self-identifiable. If >=3 points are visible in the view, pose can be computed. Since it is an emitting fiducial, the contrast is higher than passive marker and there is no light source needed on the PSC. The overall power consumption for illumination is much lower. Unlike the passive makers, it requires the makers to be powered and controlled, which makes it less desirable. It is possible to use an ld CCD sensor if all the fiducial markers are on the same level.
[0098] Optical Pose Estimation
[0099]
[0100] The equation for such estimate is:
d=(H*t)Ih
[0101] where H is the physical half height of the marker, f is the focal length in pixels (f=(resolution/2)I tan(fovl2)). It is obvious that the relationship between h and d is non-linear. (As comparison, an overhead camera provides straight linear relationship and maximized utilization of image resolution). The depth resolution can be calculated by derivative of d with respect to h.
d′=−H*f/(h″2)
[0102] The plots in
[0105] In some embodiments, the fiducial markers are configured to wrap around and fully cover the base of the surgical table. All areas can be covered by marker to maximize the probability of at least one is visible during a procedure. The size may be determined by the constraint of both near end and far end of the working range. The width height ratio of the barcode is designed to be greater to one due to the fact the foreshortening in horizontal direction is more than that in the vertical direction due to rotation. More quantitative analysis is provided in the next section. Self-identifiable sub-markers are one way to handle partial occlusion when the viewpoint is unknown. Each sub-marker has a unique ID and can be associated with the model. One sub-marker provides sufficient constraint for pose estimation but more submarkers improves accuracy.
[0106] In one aspect, the size of the barcodes comprises two factors. A lower limit is needed to make them detectable at the maximum distance and at the greatest rotation angle. An upper limit is needed to make sure at least a whole pattern is visible at the minimum working distance. In another aspect, the marker and sensors are configured to maintain a line of sight of the markers. As can be appreciated by reference to
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[0109] Other variations are within the spirit of the present invention. Thus, while the invention is susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims.
[0110] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
[0111] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.