Rotation speed feedback during imaging event

Abstract

System and methods for providing rotation speed feedback during an imaging event are provided. An example system may receive, from an imaging device included in a rotating platform, a plurality of frames of image data depicting a subject at a plurality of different rotation angles. The system may identify a plurality of reference points in an initial frame of image data, determine respective optical displacements of the plurality of reference points across frames of image data of the plurality of frames of image data, and based on the respective optical displacements, determine a rotation speed of the rotating platform. Responsive to determining the rotation speed, the system may cause a speed indicator providing an indication of the rotation speed to be displayed on a display device.

Description

Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PCROTATION SPEED FEEDBACK DURING IMAGING EVENT CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of the filing date of provisional U.S. Patent Application No. 63 / 762,449 entitled “ROTATION SPEED FEEDBACK DURING IMAGING EVENT,” filed on February 24, 2025. The entire contents of the provisional application are hereby expressly incorporated herein by reference.FIELD

[0002] The present disclosure relates to providing rotation speed feedback during an imaging event, and more particularly, to techniques for determining rotation speed based on optical displacements of reference points across frames of image data.BACKGROUND

[0003] In the field of medical imaging, the ability to capture and process quality images is important to deriving accurate insights therefrom. For example, traditional imaging techniques, such as computed tomography (CT) and fluoroscopy, are employed to capture images used to provide visual insights to medical practitioners related to a state of internal anatomy of a subject. These imaging modalities often involve rotating imaging devices attached to a C-arm around a subject to capture images from different rotation angles.Precise control over the rotation speed of the imaging device helps maximize image quality and minimize exposure of the subject to potentially harmful radiation generated by the imaging device.

[0004] An example of an imaging technique that uses images captured by a C-arm is tomosynthesis. Conventional tomosynthesis techniques may rely on a fiducial board placed beneath the subject to determine a C-arm pose estimation of the imaging device, and thus, the rotation angle, when reconstructing a three-dimensional (3D) model from a series of two-dimensional (2D) fluoroscopic images. Hence, having the fiducials of the fiducial board clearly visualized in the captured image data enables more accurate rotation angle determination used when reconstructing the three-dimensional 3D model.. Without clear visualization, the pose estimation (including rotation angle determination) may be incorrect,Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC resulting in poor reconstruction of a model of the subject when performing tomosynthesis based upon the captured image data.

[0005] One source of noise introduced into the image data captured via these rotational imaging techniques are motion artifacts introduced by the motion of the image sensor. These motion artifacts may cause the fiducials to appear blurry in the image data, which may affect the detection and / or delineation of the fiducials.

[0006] Traditional methods to control rotation speed may rely on manually adjusting the rotation speeds based upon feedback (e.g., from the imaging device) that is not provided in real-time. For example, traditional techniques that rely on the completion of a processing pipeline to detect motion of detected objects may take several seconds to derive rotational speed of the imaging sensor. As a result, by the time the system learns of the potential of the rotational speed introducing motion artifacts, the operator has already rotated the image sensor beyond an angle that can be used to reconstruct the imaged anatomy. Thus, the user is not provided timely enough feedback to be able to capture image data from the affected rotation angle in a single pass. As a result, the reconstructed model is less accurate or the operator must perform a second pass, exposing the subject to additional radiation.

[0007] Accordingly, there are opportunities for improved systems and methods for providing rotation speed feedback during an imaging event.SUMMARY OF THE DISCLOSURE

[0008] The following presents a simplified summary of various examples described herein and is not intended to identify key or critical elements or to delineate the scope of the claims.

[0009] In some examples, a system for providing rotation speed feedback during an imaging event comprises one or more processors, and one or more non-transitory, computer-readable media storing instructions that, when executed by the one or more processors, cause the system to receive, from an imaging device included in a rotating platform, a plurality of frames of image data depicting a subject at a plurality of different rotation angles. The system may identify a plurality of reference points in an initial frame of image data; determine respective optical displacements of the plurality of reference points across frames of image data of the plurality of frames of image data. Based on the respective optical displacements, the system may determine a rotation speed of the rotating platform, andIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC responsive to determining the rotation speed, cause a speed indicator providing an indication of the rotation speed to be displayed on a display device.

[0010] In other examples, a computer-implemented method for providing rotation speed feedback during an imaging event comprises receiving, via one or more processors and from an imaging device included in a rotating platform, a plurality of frames of image data depicting a subject disposed with an axis of rotation of the rotating platform. The computer-implemented method may include identifying, via the one or more processors, a plurality of reference points in an initial frame of image data, and determining, via the one or more processors, respective optical displacements of the plurality of reference points across frames of image data of the plurality of frames of image data. The computer-implemented method may include, based on the respective optical displacements, determining, via the one or more processors, a rotation speed of the rotating platform. The computer-implemented method may include, responsive determining the rotation speed, causing, via the one or more processors, a speed indicator providing an indication of the rotation speed to be displayed on a display device.

[0011] In other examples, a tangible, non-transitory, computer readable medium storing instructions that, when executed by one or more processors, cause the one or more processors to receive, from an imaging device included in a rotating platform, a plurality of frames of image data depicting a subject at a plurality of different rotation angles. The instructions may further cause the one or more processors to identify a plurality of reference points in an initial frame of image data, and determine respective optical displacements of the plurality of reference points across frames of image data of the plurality of frames of image data. Based on the respective optical displacements, the instructions may further cause the one or more processors to determine a rotation speed of the rotating platform. Responsive to determining the rotation speed, the instructions may further cause the one or more processors to cause a speed indicator providing an indication of the rotation speed to be displayed on a display device.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The figures described below depict various aspects of the system and methods disclosed therein. It should be understood that each figure depicts one embodiment of aIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC particular aspect of the disclosed system and methods, and that each of the figures is intended to accord with a possible embodiment thereof.

[0013] There are shown in the drawings arrangements which are presently discussed, it being understood, however, that the present aspects are not limited to the precise arrangements and instrumentalities shown, wherein:

[0014] FIG. 1 A depicts an example system for navigating during a medical procedure within an operating environment, according to embodiments.

[0015] FIG. IB is a simplified diagram depicting an example imaging geometry for imaging a subject, according to embodiments.

[0016] FIG. 1C schematically illustrates a projection of an example fiducial plate at a first projection angle, according to embodiments.

[0017] FIG. ID schematically illustrates a projection of an example fiducial plate at a second projection angle, according to embodiments.

[0018] FIG. 2A schematically illustrates an example first image frame and an example second image frame, according to embodiments.

[0019] FIG. 2B schematically illustrates an example third image frame associated with an undesirably fast rotation speed, according to embodiments.

[0020] FIG. 2C schematically illustrates an example fourth image frame associated with a desirable rotation speed, according to embodiments.

[0021] FIG. 2D schematically illustrates an example user interface 250 of a display device (e.g., the display unit 130), according to embodiments.

[0022] FIG. 3 depicts a flow diagram of an example computer-implemented method 300 for providing rotation speed feedback during an imaging event, according to embodiments.

[0023] FIG. 4 is a simplified diagram of a medical system, according to embodiments.

[0024] FIG. 5A is a simplified diagram of a medical instrument system, according to embodiments.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC

[0025] FIG. 5B is a simplified diagram of a medical instrument including a medical tool within an elongate device, according to embodiments.

[0026] FIGS. 6 A and 6B are simplified diagrams of side views of a patient coordinate space including a medical instrument mounted on an insertion, according to embodiments.

[0027] Examples of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures, wherein showings therein are for purposes of illustrating examples of the present disclosure and not for purposes of limiting the same.DETAILED DESCRIPTION

[0028] In the following description, specific details are set forth describing some examples consistent with the present disclosure. Numerous specific details are set forth in order to provide a thorough understanding of the examples. It will be apparent, however, to one skilled in the art that some examples may be practiced without some or all of these specific details. The specific examples disclosed herein are meant to be illustrative but not limiting. One skilled in the art may realize other elements that, although not specifically described here, are within the scope and the spirit of this disclosure. In addition, to avoid unnecessary repetition, one or more features shown and described in association with one example may be incorporated into other examples unless specifically described otherwise or if the one or more features would make an example non-functional. In some instances, well known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the examples.

[0029] The present disclosure relates to systems and methods for providing rotation speed feedback during an imaging event. An example system receives a plurality of frames of image data from an imaging device included in a rotating platform, the image data depicting a subject at a plurality of different rotation angles. The system identifies a plurality of reference points in an initial frame of image data, and determines respective optical displacements of the reference points across frames of image data. Based on the respective optical displacements, the system determines a rotation speed of the rotating platform.Responsive to determining the rotation speed, the system causes a speed indicator providing an indication of the rotation speed to be displayed on a display device. Thus, the disclosedIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC techniques capture and analyze frames of image data to determine the rotation speed of the imaging device in a manner that provides real-time feedback when the rotation speed is undesirably fast or slow. Providing real-time user imaging arm rotation speed feedback according to the disclosed techniques facilitates stable rotation spin, improving the quality of the captured images, improving event efficiency, and mitigating unnecessary radiation exposure of the subject from the imaging device.EXAMPLE SYSTEM FOR PROVIDING ROTATION SPEED FEEDBACK

[0030] FIG. 1A depicts an example system 100 for providing rotation speed feedback during an imaging event, according to embodiments. The imaging event may occur, for example, within an operating environment 101 (or other environment in which a subject may be imaged, such as an outpatient imaging facility). The system 100 may include a processing unit 120 and a display unit 130 (e.g., a medical display) communicatively coupled to an imaging unit 110 (e.g., a fluoroscopic imaging device). Although FIG. 1 A depicts the imaging unit 110 as being distinct from the system 100, in other examples, the system 100 may include the imaging unit 110.

[0031] The imaging unit 110, also referred to herein at times as an imaging device, may generate imaging data comprising one or more image frames of image data. The imaging data may include, for example, X-ray data. To that end, the imaging unit may include a C-arm fluoroscopic imaging system. Additionally, or alternatively, the frames of image data may be obtained using computed tomography (CT), thermography, ultrasound, optical coherence tomography (OCT), thermal imaging, impedance imaging, laser imaging, nanotube x-ray imaging or any other suitable imaging technique.

[0032] The system 100 may include a processing unit 120 which may include one or more processors. The one or more processors of the processing unit 120 may be configured to receive and / or analyze the image data from the imaging unit 110. Throughout the disclosure, the descriptions of example operations performed by the processing unit 120 are to be understood to be executed by the one or more processors of the processing unit 120. In some examples, the processing unit 120 may include hardware specifically configured (e.g., hardwired or programmable) to carry out at least a portion of the example operations described in this disclosure. Additionally, or alternatively, the processing unit 120 may be configured to carry out at least a portion of the example operations described in thisIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC disclosure by executing a set of software instructions. To that end, the system 100 may include or be communicatively connected to a tangible, non-transitory, computer-readable medium. The medium may store instructions which, when executed by the processing unit 120, perform any one or more of the example operations described below. For example, the instructions may cause the processing unit 120 to perform image processing operations on the images received from the imaging unit 110 and / or to perform other computations (e.g., associated with determining rotation speed).

[0033] The processing unit 120 may cause the display unit 130, also referred to herein at times as a display device, to display information based on the processing the image data. An operator (e.g., a physician, another medical practitioner, or a fully- automated robotic surgery system) of a medical system may use the information displayed at the display unit 130 to perform an imaging event. For example, the imaging unit 110 may include a rotating platform, such as the C-arm of an imaging device. The processing unit 120 may output a rotation speed of the rotating platform at the display unit 130 by generating and transmitting, to the display unit 130, data representing a user interface (e.g., graphical user interface (GUI)) that includes a speed indicator representative of the rotation speed of the rotating platform. The rotation speed information displayed at the display unit 130 may allow the operator to adjust the rotation speed of the imaging unit 110 in substantially real-time based upon the rotation speed information. For the purpose of this disclosure, “real-time” may refer to a time period that is minimally perceptible to the user (e.g., less than 10 milliseconds, less than 30 milliseconds, or less than 50 milliseconds).

[0034] One or more reference points may be visible in image frames obtained by the imaging unit 110. As will be described in more detail below, the reference points may aid in determining the rotation speed of the imaging unit 110. In at least some embodiments, the reference points may be integrated (e.g., etched, deposited, painted, or otherwise fixedly attached) with, and / or removably disposed onto, the flexible elongate device 140. For example, metal rings comprising of the body of an endoscope may act as reference points. In at least some embodiments, the reference points may include fiducial markings (e.g., included on a fiducial board captured in the image data). The fiducials may include elements of a variety of materials and / or structures such as metals, plastics, etched glass, dyes, radioactive or fluorescent markings, confined fluids (e.g., bubbles), etc. In at least some embodiments,Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC the reference points may include points derived from anatomical and / or bony structures (e.g., ribs) of a subject captured in the image data.

[0035] Furthermore, the processing unit 120 may generate a display at the display unit 130 based upon the one or more image frames depicting a subject at a plurality of different rotation angles. The processing unit 120 may update a speed indicator (e.g., a binary or multi-segment speed indicator) displayed by the display unit 130 to aid an operator with the imaging event once based upon determining optical displacement of respective reference points across frames of the images data. Additionally, or alternatively, the processing unit 120 may be configured to generate one or more alerts, notifications, indicators, and / or the like. For example, the processing unit 120 may cause the speed indicator of the display unit 130 to indicate the rotation speed of the imaging unit 110 is below or above a threshold speed, allowing the operator of the imaging unit 110 to alter the rotation speed of the imaging unit 110 based upon the speed indicator.

[0036] FIG. IB is a diagram depicting an example imaging geometry for imaging a subject, according to embodiments. According to FIG. IB, the subject S is disposed within the operating environment 101. An x-ray source 150 (the imaging unit 110) may include a rotating platform allowing the x-ray source 150 to be disposed at a location (e.g., Cl, C2, C3, etc.) along a circular arc C and directed toward a diametrically disposed detector 155 (which, likewise, may be included in the imaging unit 110) on the opposite side of the subject S. The circular arc C may lie in a plane orthogonal to an axis A disposed lengthwise through the subject S, and the center of the arc C may be disposed at the axis A. More generally, the axis A need not run lengthwise through the subject S. Generally, the axis of rotation for the arc C need not run through the patient, but may be below or above the subject S and at any suitable angle with respect to the body of the subject S. Furthermore, the arc C need not be circular to apply the techniques of the disclosure. In some examples, the arc C may be determined by the movement of a C-arm, e.g., of a fluoroscopic imaging device. The system, based on the geometry of FIG. IB may generate projections from a limited set of projection angles (e.g., 120°, 100°, 110°, 90°, 80°, 70°, 60°, or any other suitable span).

[0037] Besides passing through the subject S, x-rays emanating from the x-ray source 150 may pass through a fiducial board 160 disposed, for example, under the subject S (or any other suitable location at or near the body of the subject S). In FIG. IB, the fiducial board 160 is shown separately to illustrate example fiducial markings (e.g., reference points)Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC disposed as a grid pattern throughout the fiducial board 160, although the fiducial board 160 may include other suitable patterns of fiducial markings. The fiducial markings may be high x-ray density spheres and / or cylinders with regular or irregular diameters (e.g., 1, 2, 5, 10 mm). The fiducial marking may be spaced throughout the fiducial board 160 at regular or irregular intervals (e.g., 10, 20, 30, 40 mm). Other fiducial markings, such as lines, squares, and / or other suitable markings that have high x-ray attenuation or scattering may be included in the fiducial board 160. As described in more detail below, the system 100 may use the fiducial board 160 (and / or reference points not located on the fiducial board 160) to determine optical displacements of the fiducial markings across frames of image data, to determine a rotation speed of the rotating platform of the x-ray source 150, etc.

[0038] FIGS. 1C and ID schematically illustrate projections (i.e., projected images) of the example fiducial board 160 at two projection angles. In the illustrated example, the fiducial board 160 has fiducial markings arranged in a regular square grid, with identical spacing along two directions. Accordingly, in FIG. 1C, the projection angle may then be 0° with respect to the z-axis, i.e., normal to the plate, resulting in a regular grid of fiducial markings within the projected image of the fiducial board 160. In FIG. ID, on the other hand, the projection angle deviates from the normal, resulting in the columns of fiducial markings being closer that the rows, as well as other distortions. Certain distortions may arise from the projection angle deviating from the normal with respect to the two symmetry axes (represented by dashed lines in FIGS. 1C, ID) of the fiducial board 160. The projection in FIG. ID may additionally have a perspective distortion resulting, for example, from slightly nonparallel x-rays admitted by the imaging unit 110.

[0039] It should be appreciated that in other embodiments, the fiducial markings are irregularly arranged on the fiducial board 160. For example, the markings closest to the edge of the fiducial board 160 may have a larger diameter than fiducial markings closer to the center of the fiducial board. As a result, the processing unit 120 may be able to determine a location of a tracked fiducial marking on the fiducial board 160. Identifying the location of a tracked fiducial marking with respect to a position on the fiducial board 160 may enable the processing unit 120 to detect when the field of view is approaching the edge of the fiducial board and provide warning to the user that they are approaching the end of the limited set of projection angles.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC EXAMPLE WORKFLOW FOR PROVIDING ROTATION SPEED FEEDBACK

[0040] In operation, the system 100 may receive, from the imaging unit 110 included in a rotating platform, a plurality of frames of image data that depicts a subject (e.g., a patient) at a plurality of different rotation angles (e.g., locations Cl, C2, C3, along the circular arc C of FIG. IB).

[0041] The system 100 (e.g., via the processing unit 120) may identify a plurality of reference points in an initial frame of image data. The reference points may include fiducial markings included on a fiducial board 160, reference points derived from bony structures of the subject, reference points of a flexible elongate device, etc. For anatomical reference points, the system 100 may execute a feature classification algorithm on each frame of image data to detect the anatomical feature and define appropriate reference points at trackable locations associated with the feature (e.g., comers or joints associated with a high local intensity gradient).

[0042] The system 100 may determine respective optical displacements of the reference points across frames of image data. In one example, determining respective optical displacements of the reference points may include tracking the reference points across image frames that are sequentially captured by the imaging unit 110. The system 100 may then convert the optical displacement to a rotational speed using the techniques described below. As new frames of image data with reference points are received from the imaging unit 110, the system 100 determines new optical displacements for use when determining an updated rotational speed.

[0043] FIG. 2A schematically illustrates an example first image frame 202 and an example second image frame 204, according to embodiments. The image frames 202, 204 may be sequentially captured, wherein the imaging unit 110 captures the first image frame 202 at a first point in time t, and subsequently captures the second image frame 204 at a later point in time t + St. The image frames 202, 204 depict a set of reference points 206 (e.g., fiducials of the fiducial board 160) that have an optical displacement corresponding to the change in respective location of the set of reference points 206 between the first image frame 202 and the second image frame 204. As an example, a reference point 206A is located at a coordinate (x, y) along an x-axis and y-axis respectively in the first image frame 202, and is located at a coordinate (x + fry y + fry) in the second image frame 204, where frx and SyIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC represent the optical displacement of the reference point 206A between the first image frame 202 and the second image frame 204.

[0044] In at least some embodiments, determining optical displacements may include determining sparse optical flow or dense optical flow. Sparse optical flow can track the motion of points of interest (e.g., reference points such as fiducials or bony structures) across image frames to generate motion vectors, such as a motion vector associated with the dx and Sy motion of the reference point 206A between the first image frame 202 and the second image frame 204. Sparse optical flow may be performed using algorithms such as a Lucas-Kanade algorithm. In the Lucas-Kanade algorithm, the motion field is assumed to be constant across small periods of time (e.g., St) and a least squares solution is applied to arrive at a motion vector v that equals ATA ~1Arb, where A is a matrix formed from the partial derivatives (e.g., <5x and Sy) of the tracked reference points across the two images. Because sparse optical flow tracks a subset of the image data (the reference points), determining sparse optical flow is typically a faster operation than determining dense optical flow. Thus, by defining a set of reference points to track via sparse optical flow techniques, rotational speed can be determined fast enough to provide real-time feedback to a user.

[0045] On the other hand, dense optical flow tracks the motion of all pixels across image frames to generate a motion field. While slower, dense optical flow techniques may be useful for situations where there are insufficient reference points for the sparse optical flow algorithms to provide accurate results. Accordingly, in at least some embodiments, the system 100 may determine that a threshold number of reference points are not detected within one or more frames of image data. When the threshold number of reference points are not detected within one or more frames of image data, the system 100 may instead apply a dense optical flow tracking algorithm to frames of the image data. In these embodiments, the system 100 may warn the user that dense optical flow techniques are being applied such that the user may be alerted to the fact that the speed indicator is being updated at a slower rate.

[0046] Based on the respective optical displacements, the system 100 may determine a rotation speed of the rotating platform. In some examples, the system 100 may convert the optical flow velocity vector into a rotational speed using the known geometric relationship between the imaged fiducial markings (or other reference points) and the position of the image sensor. For example, a registered position of the fiducial board and / or reference anatomy may be compared to a kinematically-derived position of the image sensor toIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC determine an imaging distance as part of the rotational speed calculation. In other examples, the determined optical flow velocity is used as a proxy for the rotation speed. In these examples, the rotation speed may not need to be expressly calculated.

[0047] Regardless of the rotation speed metric, the rotation speed may be determined within substantially real-time time (e.g., 10 millisecond, 30 milliseconds, 50 milliseconds, etc.) of receiving a frame of image data. In at least some embodiments, the rotation speed may be based, in part, on a combination of rotation speeds determined for a predetermined or particular number of prior frames of image data. For example, the system 100 may combine the rotation speeds associated with prior frames of image data by performing an exponential moving average that weights more recent determinations more highly than older determinations. As a result, the time function of the determined rotation speeds is smoother, which may prevent outlier rotation speed determinations from triggering a warning.

[0048] In at least some embodiments, the system 100 may obtain a reference rotation speed (e.g., determined by the imaging unit 110 or otherwise rotating platform) that is associated with a particular rotation angle. As described above, by determining rotation speed based on the optical flow, the rotation speed may be determined more quickly than an imaging system is able to process and output the captured image data. Thus, while the rotation speeds provided by the imaging unit 110 may be too slow for real-time feedback, these measurements are typically more accurate and can be used to calibrate the real-time rotation speed determination based on the optical flow.

[0049] Accordingly, the system 100 may determine a variance metric (e.g., between the reference rotation speed and a determined rotation speed associated with the same frame of image data). The variance metric may be based on a difference between the reference rotation speed and the determined rotation speed for the frame. The system 100 may adjust a correspondence between the optical displacements and rotation speed based upon the variance metric. For example, the system 100 may adjust one or more constants or scalars used to convert the optical flow into a rotational speed such that the calculation better aligns with the reference rotation speed data. In some embodiments, a fitting algorithm (e.g., a linear regression) is applied to adjust the constants and / or scalars to account for the differences across a series frames of image data.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC

[0050] In response to determining the rotation speed, the system 100 may cause a speed indicator to be displayed on the display unit 130. The speed indicator may provide an indication of the rotation speed of the rotating platform of the imaging unit 110. The speed indicator may be, or include, a binary speed indicator, a numerical speed indicator, a color-coded speed indicator (e.g., green associated with desirable speeds, yellow associated with undesirably slow speeds, and red associated with undesirably fast speeds), a multi-segment speed indicator (e.g., each segment associated with a range of rotation speeds), and / or any other suitable speed indicator. It should be appreciated that while visual indications are described herein, in some embodiments, alternative notification modalities (e.g., audio, haptic, augmented reality, etc.) may be additionally or alternatively utilized.

[0051] In at least some embodiments, the system 100 may determine, and / or provide an indication that (e.g., via the speed indicator, a separate indicator), the rotation speed exceeds a rotation speed threshold. In one example, the threshold rotation speed may correspond to a rotation speed at which artifacts are introduced in the image frames, such as due to an undesirably fast rotation speed. The artifacts may cause objects in the image frame, such as the subject, the reference points, a medical instrument, etc., to appear blurry. In some embodiments, this speed is determined during a calibration process prior to operation. In other embodiments, this speed is included in predetermined configuration information associated with the imaging unit 110. For embodiments with a binary speed indicator, this threshold may be associated with when to trigger the alert state of the binary indicator. For embodiments with multi-segment indicators, this threshold may be associated with one of the segments most associated with fast rotation speeds.

[0052] It should be appreciated that excessively slow speeds may also have undesired effects. For example, a subject may be exposed to unnecessary radiation if the imaging unit 110 is rotated more slowly than necessary to provide quality image data. Accordingly, in some embodiments, a threshold rotation speed may be defined to cause the operator to rotate the imaging unit 110 more quickly. In some embodiments, the rotation speed may be defined based on characteristics of the imaging unit 110 (e.g., frame rate, image resolution, etc.).

[0053] As described above, it may be desirable to know when the field of view of the imaging unit 110 is proximate to the edge of the detection range (e.g., the end of the fiducial board) to know when to stop the rotation of the imaging unit 110. Accordingly, to detect that the rotation angle is approaching the limit of the working range, system 100 may analyze theIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC distribution of reference points in one or more image frames to determine whether the imaging unit 110 has a field of view proximate to the edge of the fiducial board or otherwise reference points. For example, as described above, a fiducial board may have fiducial markings of irregular sizes (e.g., markings with larger diameters closer to the edge of the fiducial board). Accordingly, the system 100 may detect that the optical flow for fiducial markings associated with particular diameters are moving towards an edge of the frame. In some embodiments, the system 100 may look at the distribution of reference points (e.g., as determined based upon diameter) to determine that the optical flow is toward the edge of the fiducial board (as opposed to towards the middle of the fiducial board). If the system 100 determines that the rotation angle of the imaging unit 110 has a field of view proximate to the edge of the fiducial board, the system 100 may cause a notification to be displayed on the display unit 130 to alert the user that they are approaching the edge of the viewing range of the imaging unit 110.

[0054] FIG. 2B schematically illustrates an example third image frame 220 associated with an undesirably fast rotation speed, according to embodiments. In the third image frame 220, the image data (including the tracked reference points, such as fiducial markings) appear blurry due to the rotation speed being undesirably fast. As a result, it may be difficult to resolve the reference points in the image data, leading to less accurate reconstruction of the imaged subject during, for example, a tomosynthesis process. Thus, the third frame of image data 220 may also referred to as an example of a “bad spin.”

[0055] Conversely, FIG. 2C schematically illustrates an example fourth image frame 230 associated with a desirable rotation speed, according to embodiments. The fourth image frame 230 includes a feature of a bony structure 232 and a fiducial marking on the flexible elongate device 234, which in addition (or alternatively) to the fiducial markings on a fiducial board, may act as reference points when determining optical flow. In the fourth image frame 230, the image data are not blurry due to the rotation speed being within a desirable range. Thus, the fourth frame of image data may also be referred to as an example of a “good spin.”

[0056] FIG. 2D schematically illustrates an example user interface 250 of a display device (e.g., the display unit 130), according to embodiments. The user interface 250 includes a multi-segment speed indicator 252 providing an indication of the rotation speed of the rotation platform of the imaging unit 110. As illustrated, the multi-segment speed indicator includes 5 segments, but in other examples, any number of segments may be used. AsIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC described above, each segment of the multi-segment speed indicator 252 is associated with respective ranges of rotation speed.

[0057] As illustrated, the user interface 250 also includes a binary speed indicator 256. In this example, the outer circle may be depicted in a first manner when the rotation speed is within a desirable range (e.g., in a green color or a color that blends into the background) and in a second manner when the rotation speed exceeds a threshold (e.g., in red or yellow).

[0058] The example user interface 250 also includes an alert 254 informing the operator that the rotation speed of the imaging unit 110 exceeds a threshold speed and the operator should slow down the rotation speed of the imaging unit 110. It should be appreciated that the example indications 252, 254, and 256 are only one example of providing an alert to the operator, and in alternate embodiments, the user interface 250 may include additional, alternative, and / or fewer interface elements informing the operator of the rotation speed of the imaging unit 110.

[0059] As described herein, if the rotation speed exceeds a threshold, the system 100 may store an indication of the rotation angles that may have been impacted by motion artifacts. Accordingly, when the operator has completed a spin of the imaging unit 110 in a first direction, the system 100 may generate an alert that the operator should rotate the imaging unit 110 back the other way to capture additional image data of the subject to account for the frames of image data being potentially degraded by motion artifacts. It should be appreciated in this return rotation, the system 100 may refrain from capturing image data at rotation angles associated with good image data to minimize the amount of radiation to which the subject is exposed.

[0060] In at least some embodiments, after the system 100 has collected the frames of image data from a plurality of rotation angles, the system 100 may reconstruct a three-dimensional model of the subject by performing, for example, tomosynthesis techniques based upon the plurality of frames of two-dimensional image data. The system 100 may implement any suitable tomosynthesis process (e.g., using FDK reconstruction or any other suitable reconstruction technique) to generate the 3D model of the subject. It should be appreciated that in some embodiments, the frames of image data are pre-processed prior to reconstruction to further improve the quality of the reconstructed model.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC

[0061] In at least some embodiments, a field of view (FOV) mask may be applied to the imaging unit 110 and / or image frame, the FOV mask associated masking (e.g., covering) a first portion of the image frames, leaving a second portion of the image frames uncovered and / or viewable that is less than the entire image frame. The system 100 may use the FOV mask to focus image frame analysis on the second portion of the image frames, which may improve the accuracy and / or speed of calculations (e.g., optical displacement, rotation speed, etc.) or steps associated with providing rotation speed feedback during an imaging event. Returning to FIG. 2D, a circular FOV mask was implemented, but in other embodiments, masks of other shapes may be utilized (e.g., rectangular, square, etc.).EXAMPLE METHOD FOR PROVIDING ROTATION SPEED FEEDBACK

[0062] FIG. 3 depicts a flow diagram of an example computer-implemented method 300 for providing rotation speed feedback during an imaging event, according to embodiments. The computer-implemented method 300 may be performed and / or implemented by, for example, via the system 100 (e.g., the processing unit 120) and / or one or more processors.

[0063] The computer-implemented method 300 may include receiving, from an imaging device (e.g., the imaging unit 110) included in a rotating platform, a plurality of frames of image data depicting a subject at a plurality of different rotation angles (block 310). The rotating platform may include a C-arm of a fluoroscopic imaging device.

[0064] The computer-implemented method 300 may include identifying a plurality of reference points in an initial frame of image data (block 320). The plurality of reference points (e.g., the set of reference points 206) may include fiducial markings such as fiducial markings included on a fiducial board (e.g., the fiducial board 160) and / or points derived from anatomical structures (e.g., bony structures such as ribs) depicted in the plurality of frames of image data.

[0065] The computer-implemented method 300 may include determining respective optical displacements of the plurality of reference points across frames of image data of the plurality of frames of image data (block 330), such as tracking the reference points across sequential frames of image data. The computer-implemented method 300 may include determining a new set of respective optical displacements across the frames of image data as new frames of image data are received. In at least some embodiments, the computer-implemented methodIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC 300 may include determining respective diameters of the fiducial markings, and scaling the optical displacements based on the respective diameters.

[0066] Determining respective optical displacements (block 330) may include determining sparse optical flow using a Lucas-Kanade method and / or performing outlier removal with respect to the respective optical displacements. In at least some embodiments, the computer-implemented method 300 may include determining that a frame of image data does not include a threshold number of reference points, and responsive to the determination, applying a dense optical flow tracking algorithm.

[0067] The computer-implemented method 300 may include based on the respective optical displacements, determining a rotation speed of the rotating platform (block 340). The rotation speed may be determined within a particular period of time of receiving a new frame of image data (e.g., 10 milliseconds, 30 milliseconds, 50 milliseconds, etc.). The rotation speed may be based on a combination of rotation speeds determined responsive to receiving a predetermined number of prior frames of image data. In some such embodiments, the combination of rotation speeds may be based on an exponential moving average of the rotation speeds determined responsive to the predetermined number of prior frames.

[0068] The computer-implemented method 300 may include responsive to determining the rotation speed, causing a speed indicator providing an indication of the rotation speed to be displayed on a display device (block 350). The speed indicator may include a binary speed indicator, a multi-segment speed indicator (e.g., each segment associated with a respective range of rotation speeds), and / or other suitable speed indicator. Providing the indication includes determining whether the rotation speed exceeds a threshold rotation speed, such as the rotation speed at which artifacts are introduced in the depiction of the subject in the plurality of frames of image data. Providing the indication of the rotation speed may include determining that the rotation speed is below a threshold speed below which the subject is exposed to unnecessary radiation, and providing an indication that the rotation speed is too slow.

[0069] The computer-implemented method 300 may include detecting that a frame of image data is associated with a rotation speed exceeding a threshold, determining a rotation angle associated with the frame of image data, and causing the display device to display anIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC indication to rotate the rotating platform in a direction that captures a new frame of image data associated with the rotation angle.

[0070] The computer-implemented method 300 may include obtaining a reference rotation speed associated with a particular rotation angle from the rotating platform, determining a variance metric between the reference rotation speed and determined rotation speed, and adjusting a correspondence between the optical displacements and rotation speed based upon the variance metric.

[0071] The computer-implemented method 300 may include reconstructing a model of the subject based upon performing tomosynthesis of the plurality of frames of image data.

[0072] FIGS. 4-6B depict diagrams of a medical system that may be used for manipulating a medical instrument that includes a flexible elongate device according to any of the methods and systems described above, in some examples. For example, each reference above to the “system” may refer to a system (e.g., system 700) discussed below, or to a subsystem thereof.

[0073] FIG. 4 is a simplified diagram of a medical system 700 according to some examples. The medical system 700 may include at least portions of the system 100 described with reference to FIG. 1 A. The medical system 700 may be suitable for use in, for example, surgical, diagnostic (e.g., biopsy), or therapeutic (e.g., ablation, electroporation, etc.) procedures. While some examples are provided herein with respect to such procedures, any reference to medical or surgical instruments and medical or surgical methods is non-limiting. The systems, instruments, and methods described herein may be used for animals, human cadavers, animal cadavers, portions of human or animal anatomy, non-surgical diagnosis, as well as for industrial systems, general or special purpose robotic systems, general or special purpose teleoperational systems, or robotic medical systems.

[0074] As shown in FIG. 4, medical system 700 may include a manipulator assembly 702 that controls the operation of a medical instrument 704 in performing various procedures on a patient P (e.g., subject S, as in FIG. IB). The medical instrument 704 may include a flexible elongated device. Medical instrument 704 may extend into an internal site within the body of patient P via an opening in the body of patient P. The manipulator assembly 702 may be teleoperated, non-teleoperated, or a hybrid teleoperated and non-teleoperated assembly with one or more degrees of freedom of motion that may be motorized and / or one or more degrees of freedom of motion that may be non-motorized (e.g., manually operated). The manipulator assembly 702 may be mounted to and / or positioned near patient table T. A leader assemblyIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC 706 allows an operator O (e.g., a surgeon, a clinician, a physician, or other user, as described above) to control the manipulator assembly 702. In some examples, the leader assembly 706 allows the operator O to view the procedural site or other graphical or informational displays (such as the user interface 250 of FIG. 2D). In some examples, the manipulator assembly 702 may be excluded from the medical system 700 and the medical instrument 704 may be controlled directly by the operator O. In some examples, the manipulator assembly 702 may be manually controlled by the operator O. Direct operator control may include various handles and operator interfaces for hand-held operation of the medical instrument 704.

[0075] The leader assembly 706 may be located at a surgeon’s console which is in proximity to (e.g., in the same room as) the patient table T on which patient P is located, such as at the side of the patient table T. In some examples, the leader assembly 706 is remote from the patient table T, such as in in a different room or a different building from the patient table T. The leader assembly 706 may include one or more control devices for controlling the manipulator assembly 702. The control devices may include any number of a variety of input devices, such as joysticks, trackballs, scroll wheels, directional pads, buttons, data gloves, trigger-guns, hand-operated controllers, voice recognition devices, motion or presence sensors, and / or the like.

[0076] The manipulator assembly 702 supports the medical instrument 704 and may include a kinematic structure of links that provide a set-up structure. The links may include one or more non-servo-controlled links (e.g., one or more links that may be manually positioned and locked in place) and / or one or more servo-controlled links (e.g., one or more links that may be controlled in response to commands, such as from a control system 712). The manipulator assembly 702 may include a plurality of actuators (e.g., motors) that drive inputs on the medical instrument 704 in response to commands, such as from the control system 712. The actuators may include drive systems that move the medical instrument 704 in various ways when coupled to the medical instrument 704. For example, one or more actuators may advance medical instrument 704 into a naturally or surgically created anatomic orifice. Actuators may control articulation of the medical instrument 704, such as by moving the distal end (or any other portion) of medical instrument 704 in multiple degrees of freedom. These degrees of freedom may include three degrees of linear motion (e.g., linear motion along the X, Y, Z Cartesian axes) and in three degrees of rotational motion (e.g., rotation about the X, Y, Z Cartesian axes). One or more actuators may control rotation of the medical instrument about a longitudinal axis. Actuators can also be used to move anIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC articulable end effector of medical instrument 704, such as for grasping tissue in the jaws of a biopsy device and / or the like, or may be used to move or otherwise control tools (e.g., imaging tools, ablation tools, biopsy tools, electroporation tools, etc.) that are inserted within the medical instrument 704.

[0077] The control system 712 may include at least portions of the processing unit 120. Additionally or alternatively, the control system 712 may be in communicative connection with the processing unit 120. In some examples, the output of the processing unit 120 according to the techniques described above may cause the control system 712 to autonomously (without input from the operator O) control certain movements of the medical instrument 704.

[0078] The medical system 700 may include a sensor system 708 with one or more subsystems for receiving information about the manipulator assembly 702 and / or the medical instrument 704. Such sub-systems may include a position sensor system (e.g., that uses electromagnetic (EM) sensors or other types of sensors that detect position or location); a shape sensor system for determining the position, orientation, speed, velocity, pose, and / or shape of a distal end and / or of one or more segments along a flexible body of the medical instrument 704; a visualization system for capturing images, such as from the distal end of medical instrument 704 or from some other location; and / or actuator position sensors such as resolvers, encoders, potentiometers, and the like that describe the rotation and / or orientation of the actuators controlling the medical instrument 704. The subsystems may include an imaging sub-system (e.g., using a color imaging device, an infrared imaging device, an ultrasound imaging device, an x-ray imaging device, a fluoroscopic imaging device, a computed tomography (CT) imaging device, a magnetic resonance imaging (MRI) imaging device, or some other type of imaging device), such as the imaging unit 110.

[0079] It should be noted that the positions and orientations of sensors in the sensor system 708 may be determined in the sensor coordinate system. In some examples, the sensor coordinate system is integrated with or identical to the coordinate system of the manipulator assembly 702.

[0080] The medical system 700 may include a display system 710 (e.g., display unit 130) for displaying an image or representation of the procedural site and the medical instrument 704. Display system 710 and leader assembly 706 may be oriented so physician O canIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC control medical instrument 704 and leader assembly 706 with the perception of telepresence. The display system 710 may include at least portions of the display unit 130.

[0081] In some examples, the medical instrument 704 may include a visualization system, which may include an image capture assembly that records a concurrent or real-time image of a procedural site and provides the image to the operator O through one or more displays of display system 710. The image capture assembly may include various types of imaging devices. The concurrent image may be, for example, a two-dimensional image or a three-dimensional image captured by an endoscope positioned within the anatomical procedural site. The visualization system may obtain intra-operative images in image system coordinates, distinct from the sensor system coordinates. In some examples, the visualization system may include endoscopic components that may be integrally or removably coupled to medical instrument 704. Additionally or alternatively, a separate endoscope, attached to a separate manipulator assembly, may be used with medical instrument 704 to image the procedural site. The visualization system may be implemented as hardware, firmware, software or a combination thereof which interact with or are otherwise executed by one or more computer processors, such as of the control system 712.

[0082] Display system 710 may also display an image of the procedural site and medical instruments, which may be captured by the visualization system. In some examples, the medical system 700 provides a perception of telepresence to the operator O. For example, images captured by an imaging device at a distal portion of the medical instrument 704 may be presented by the display system 710 to provide the perception of being at the distal portion of the medical instrument 704 to the operator O. The input to the leader assembly 706 provided by the operator O may move the distal portion of the medical instrument 704 in a manner that corresponds with the nature of the input (e.g., distal tip turns right when a trackball is rolled to the right) and results in corresponding change to the perspective of the images captured by the imaging device at the distal portion of the medical instrument 704. As such, the perception of telepresence for the operator O is maintained as the medical instrument 704 is moved using the leader assembly 706. The operator O can manipulate the medical instrument 704 and hand controls of the leader assembly 706 as if viewing the workspace in substantially true presence, simulating the experience of an operator that is physically manipulating the medical instrument 704 from within the patient anatomy.

[0083] In some examples, the display system 710 may present virtual images of a procedural site that are created using image data recorded pre-operatively or intra-Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC operatively, such as image data created using computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), fluoroscopy, thermography, ultrasound, optical coherence tomography (OCT), thermal imaging, impedance imaging, laser imaging, nanotube X-ray imaging, and / or the like. The virtual images may include two-dimensional, three-dimensional, or higher-dimensional (e.g., including, for example, time based or velocity-based information) images. In some examples, one or more models are created from pre-operative or intra-operative image data sets and the virtual images are generated using the one or more models.

[0084] In some examples, for purposes of imaged guided medical procedures, display system 710 may display a virtual image that is generated based on tracking the location of medical instrument 704. For example, the tracked location of the medical instrument 704 may be registered (e.g., dynamically referenced) with the model generated using the preoperative or intra-operative images, with different portions of the model correspond with different locations of the patient anatomy. As the medical instrument 704 moves through the patient anatomy, the registration is used to determine portions of the model corresponding with the location and / or perspective of the medical instrument 704 and virtual images are generated using the determined portions of the model. This may be done to present the operator O with virtual images of the internal procedural site from viewpoints of medical instrument 704 that correspond with the tracked locations of the medical instrument 704.

[0085] The display system 710 may include the display unit 130 and may display images including the position, orientation, and / or pose of the medical instrument 704 in a joint coordinate system based on registering the sensor coordinate system with the imaging coordinate system according to the techniques described above.

[0086] The medical system 700 may also include the control system 712, which may include processing circuitry (e.g., the processing unit 120) that implements some or all of the methods or functionality discussed herein. The control system 712 may include at least one memory and at least one processor for controlling the operations of the manipulator assembly 702, the medical instrument 704, the leader assembly 706, the sensor system 708, and / or the display system 710. Control system 712 may include instructions (e.g., a non-transitory machine-readable medium storing the instructions) that when executed by the at least one processor, configures the one or more processors to implement some or all of the methods or functionality discussed herein. While the control system 712 is shown as a single block in FIG. 4, the control system 712 may include two or more separate data processing circuitsIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC with one portion of the processing being performed at the manipulator assembly 702, another portion of the processing being performed at the leader assembly 706, and / or the like. In some examples, the control system 712 may include other types of processing circuitry, such as application-specific integrated circuits (ASICs) and / or field-programmable gate array (FPGAs). The control system 712 may be implemented using hardware, firmware, software, or a combination thereof.

[0087] In some examples, the control system 712 may receive feedback from the medical instrument 704, such as force and / or torque feedback. Responsive to the feedback, the control system 712 may transmit signals to the leader assembly 706. In some examples, the control system 712 may transmit signals instructing one or more actuators of the manipulator assembly 702 to move the medical instrument 704. In some examples, the control system 712 may transmit informational displays regarding the feedback to the display system 710 for presentation or perform other types of actions based on the feedback.

[0088] The control system 712 may include a virtual visualization system to provide navigation assistance to operator O when controlling the medical instrument 704 during an image-guided medical procedure. Virtual navigation using the virtual visualization system may be based upon an acquired pre-operative or intra-operative dataset of anatomic passageways of the patient P. The control system 712 or a separate computing device may convert the recorded images, using programmed instructions alone or in combination with operator inputs, into a model of the patient anatomy. The model may include a segmented two-dimensional or three-dimensional composite representation of a partial or an entire anatomic organ or anatomic region. An image data set may be associated with the composite representation. The virtual visualization system may obtain sensor data from the sensor system 708 that is used to compute an (e.g., approximate) location of the medical instrument 704 with respect to the anatomy of patient P. The sensor system 708 may be used to register and display the medical instrument 704 together with the pre-operatively or intra-operatively recorded images. For example, PCT Publication WO 2016 / 191298 (published December 1, 2016 and titled “Systems and Methods of Registration for Image Guided Surgery”), which is incorporated by reference herein in its entirety, discloses example systems. Additionally or alternatively, the registration may be based on the techniques discussed.

[0089] During a virtual navigation procedure, the sensor system 708 may be used to compute the (e.g., approximate) location of the medical instrument 704 with respect to the anatomy of patient P. The location can be used to produce both macro-level (e.g., external)Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC tracking images of the anatomy of patient P and virtual internal images of the anatomy of patient P. The system may include one or more electromagnetic (EM) sensors, fiber optic sensors, and / or other sensors to register and display a medical instrument together with pre-operatively recorded medical images. For example, U.S. Patent No. 8,900,131 (filed May 13, 2011 and titled “Medical System Providing Dynamic Registration of a Model of an Anatomic Structure for Image-Guided Surgery”), which is incorporated by reference herein in its entirety, discloses example systems.

[0090] Medical system 700 may further include operations and support systems (not shown) such as illumination systems, steering control systems, irrigation systems, and / or suction systems. In some examples, the medical system 700 may include more than one manipulator assembly and / or more than one leader assembly. The exact number of manipulator assemblies may depend on the medical procedure and space constraints within the procedural room, among other factors. Multiple leader assemblies may be co-located or they may be positioned in separate locations. Multiple leader assemblies may allow more than one operator to control one or more manipulator assemblies in various combinations.

[0091] FIG. 5A is a simplified diagram of a medical instrument system 800 according to some examples. The medical instrument system 800 includes a flexible elongate device 802, also referred to as elongate device 802, a drive unit 804, and a medical tool 826 that collectively is an example of a medical instrument 704 of a medical system 700. The medical system 700 may be a teleoperated system, a non-teleoperated system, or a hybrid teleoperated and non-teleoperated system, as explained with reference to FIG. 4. A visualization system 831, tracking system 830, and navigation system 832 are also shown in FIG. 5 A and are example components of the control system 712 of the medical system 700. In some examples, the medical instrument system 800 may be used for non-teleoperational exploratory procedures or in procedures involving traditional manually operated medical instruments, such as endoscopy. The medical instrument system 800 may be used to gather (e.g., measure) a set of data points corresponding to locations within anatomic passageways of a patient, such as patient P.

[0092] The elongate device 802 is coupled to the drive unit 804. The elongate device 802 includes a channel 821 through which the medical tool 826 may be inserted. The elongate device 802 navigates within patient anatomy to deliver the medical tool 826 to a procedural site. The elongate device 802 includes a flexible body 816 having a proximal end 817 and aIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC distal end 818. In some examples, the flexible body 816 may have an approximately 3 mm outer diameter. Other flexible body outer diameters may be larger or smaller.

[0093] Medical instrument system 800 may include the tracking system 830 for determining the position, orientation, speed, velocity, pose, and / or shape of the flexible body 816 at the distal end 818 and / or of one or more segments 824 along flexible body 816, as will be described in further detail below. The tracking system 830 may include one or more sensors and / or imaging devices. The flexible body 816, such as the length between the distal end 818 and the proximal end 817, may include multiple segments 824. The tracking system 830 may be implemented using hardware, firmware, software, or a combination thereof. In some examples, the tracking system 830 is part of control system 712 shown in FIG. 4. The tracking system 830 may implement at least some of the techniques described, and, to that end, may include at least portions of or be in communicative connection with the processing unit 120 of FIG. 1A.

[0094] Tracking system 830 may track the distal end 818 and / or one or more of the segments 824 of the flexible body 816 using a shape sensor 822. It should be noted that, with the techniques of the instant disclosure, the shape sensor 822 may be omitted. The shape sensor 822 may include an optical fiber aligned with the flexible body 816 (e.g., provided within an interior channel of the flexible body 816 or mounted externally along the flexible body 816). In some examples, the optical fiber may have a diameter of approximately 800pm. In other examples, the diameter may be larger or smaller. The optical fiber of the shape sensor 822 may form a fiber optic bend sensor for determining the shape of flexible body 816. Optical fibers including Fiber Bragg Gratings (FBGs) may be used to provide strain measurements in structures in one or more dimensions. Various systems and methods for monitoring the shape and relative position of an optical fiber in three dimensions, which may be applicable in some examples, are described in U.S. Patent Application Publication No. 2006 / 0013523 (filed July 13, 2005 and titled “Fiber optic position and shape sensing device and method relating thereto”); U.S. Patent No. 7,772,541 (filed on March 12, 2008 and titled “Fiber Optic Position and / or Shape Sensing Based on Rayleigh Scatter”); and U.S. Patent No. 8,773,650 (filed on Sept. 2, 2010 and titled “Optical Position and / or Shape Sensing”), which are all incorporated by reference herein in their entireties. Sensors in some examples may employ other suitable strain sensing techniques, such as Rayleigh scattering, Raman scattering, Brillouin scattering, and Fluorescence scattering.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC

[0095] In some examples, the shape of the flexible body 816 may be determined using other techniques. For example, a history of the position and / or pose of the distal end 818 of the flexible body 816 can be used to reconstruct the shape of flexible body 816 over an interval of time (e.g., as the flexible body 816 is advanced or retracted within a patient anatomy). In some examples, the tracking system 830 may alternatively and / or additionally track the distal end 818 of the flexible body 816 using a position sensor system 820. Position sensor system 820 may be a component of an EM sensor system with the position sensor system 820 including one or more position sensors. Although the position sensor system 820 is shown as being near the distal end 818 of the flexible body 816 to track the distal end 818, the number and location of the position sensors of the position sensor system 820 may vary to track different regions along the flexible body 816. In one example, the position sensors include conductive coils that may be subjected to an externally generated electromagnetic field. Each coil of position sensor system 820 may produce an induced electrical signal having characteristics that depend on the position and orientation of the coil relative to the externally generated electromagnetic field. The position sensor system 820 may measure one or more position coordinates and / or one or more orientation angles associated with one or more portions of flexible body 816. In some examples, the position sensor system 820 may be configured and positioned to measure six degrees of freedom, e.g., three position coordinates X, Y, Z and three orientation angles indicating pitch, yaw, and roll of a base point. In some examples, the position sensor system 820 may be configured and positioned to measure five degrees of freedom, e.g., three position coordinates X, Y, Z and two orientation angles indicating pitch and yaw of a base point. Further description of a position sensor system, which may be applicable in some examples, is provided in U.S. Patent No. 6,380,732 (filed August 11, 1999 and titled “Six-Degree of Freedom Tracking System Having a Passive Transponder on the Object Being Tracked”), which is incorporated by reference herein in its entirety.

[0096] A processing unit (e.g., processing unit 120) may enhance the accuracy of positions obtained by the position sensor system 820 by combing data obtained by the position sensor system 820 with data obtained by an external imaging system (e.g., by way of the imaging unit 110) according to the techniques of this disclosure described above.

[0097] In some examples, the tracking system 830 may alternately and / or additionally rely on a collection of pose, position, and / or orientation data stored for a point of an elongate device 802 and / or medical tool 826 captured during one or more cycles of alternating motion,Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC such as breathing. This stored data may be used to develop shape information about the flexible body 816. In some examples, a series of position sensors (not shown), such as EM sensors like the sensors in position sensor system 820 or some other type of position sensors may be positioned along the flexible body 816 and used for shape sensing. In some examples, a history of data from one or more of these position sensors taken during a procedure may be used to represent the shape of elongate device 802, particularly if an anatomic passageway is generally static.

[0098] FIG. 5B is a simplified diagram of the medical tool 826 within the elongate device 802 according to some examples. The flexible body 816 of the elongate device 802 may include the channel 821 sized and shaped to receive the medical tool 826. In some examples, the medical tool 826 may be used for procedures such as imaging, surgery, biopsy, ablation, illumination, irrigation, suction, electroporation, etc. Medical tool 826 can be deployed through channel 821 of flexible body 816 and operated at a procedural site within the anatomy. Medical tool 826 may be, for example, an image capture probe, a biopsy tool (e.g., a needle, grasper, brush, etc.), an ablation tool (e.g., a laser ablation tool, radio frequency (RF) ablation tool, cryoablation tool, thermal ablation tool, heated liquid ablation tool, etc.), an electroporation tool, and / or another surgical, diagnostic, or therapeutic tool. In some examples, the medical tool 826 may include an end effector having a single working member such as a scalpel, a blunt blade, an optical fiber, an electrode, and / or the like. Other end types of end effectors may include, for example, forceps, graspers, scissors, staplers, clip appliers, and / or the like. Other end effectors may further include electrically activated end effectors such as electrosurgical electrodes, transducers, sensors, and / or the like.

[0099] The medical tool 826 may be a biopsy tool used to remove sample tissue or a sampling of cells from a target anatomic location. In some examples, the biopsy tool is a flexible needle. The biopsy tool may further include a sheath that can surround the flexible needle to protect the needle and interior surface of the channel 821 when the biopsy tool is within the channel 821. The medical tool 826 may be an image capture probe that includes a distal portion with a stereoscopic or monoscopic camera that may be placed at or near the distal end 818 of flexible body 816 for capturing images (e.g., still or video images). The captured images may be processed by the visualization system 831 for display and / or provided to the tracking system 830 to support tracking of the distal end 818 of the flexible body 816 and / or one or more of the segments 824 of the flexible body 816. The image capture probe may include a cable for transmitting the captured image data that is coupled toIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC an imaging device at the distal portion of the image capture probe. In some examples, the image capture probe may include a fiber-optic bundle, such as a fiberscope, that couples to a more proximal imaging device of the visualization system 831. The image capture probe may be single- spectral or multi-spectral, for example, capturing image data in one or more of the visible, near-infrared, infrared, and / or ultraviolet spectrums. The image capture probe may also include one or more light emitters that provide illumination to facilitate image capture. In some examples, the image capture probe may use ultrasound, x-ray, fluoroscopy, CT, MRI, or other types of imaging technology.

[0100] In some examples, the image capture probe is inserted within the flexible body 816 of the elongate device 802 to facilitate visual navigation of the elongate device 802 to a procedural site and then is replaced within the flexible body 816 with another type of medical tool 826 that performs the procedure. In some examples, the image capture probe may be within the flexible body 816 of the elongate device 802 along with another type of medical tool 826 to facilitate simultaneous image capture and tissue intervention, such as within the same channel 821 or in separate channels. A medical tool 826 may be advanced from the opening of the channel 821 to perform the procedure (or some other functionality) and then retracted back into the channel 821 when the procedure is complete. The medical tool 826 may be removed from the proximal end 817 of the flexible body 816 or from another optional instrument port (not shown) along flexible body 816.

[0101] In some examples, the elongate device 802 may include integrated imaging capability rather than utilize a removable image capture probe. For example, the imaging device (or fiber-optic bundle) and the light emitters may be located at the distal end 818 of the elongate device 802. The flexible body 815 may include one or more dedicated channels that carry the cable(s) and / or optical fiber(s) between the distal end 818 and the visualization system 831. Here, the medical instrument system 800 can perform simultaneous imaging and tool operations.

[0102] In some examples, the medical tool 826 is capable of controllable articulation. The medical tool 826 may house cables (which may also be referred to as pull wires), linkages, or other actuation controls (not shown) that extend between its proximal and distal ends to controllably bend the distal end of medical tool 826, such as discussed herein for the flexible elongate device 802. The medical tool 826 may be coupled to a drive unit 804 and the manipulator assembly 702. In these examples, the elongate device 802 may be excluded from the medical instrument system 800 or may be a flexible device that does not haveIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC controllable articulation. Steerable instruments or tools, applicable in some examples, are further described in detail in U.S. Patent No. 7,316,681 (filed on Oct. 4, 2005 and titled “Articulated Surgical Instrument for Performing Minimally Invasive Surgery with Enhanced Dexterity and Sensitivity”) and U.S. Patent No. 9,259,274 (filed Sept. 30, 2008 and titled “Passive Preload and Capstan Drive for Surgical Instruments”), which are incorporated by reference herein in their entireties.

[0103] The flexible body 816 of the elongate device 802 may also or alternatively house cables, linkages, or other steering controls (not shown) that extend between the drive unit 804 and the distal end 818 to controllably bend the distal end 818 as shown. In some examples, at least four cables are used to provide independent up-down steering to control a pitch of the distal end 818 and left-right steering to control a yaw of the distal end 881. In these examples, the flexible elongate device 802 may be a steerable catheter. Examples of steerable catheters, applicable in some examples, are described in detail in PCT Publication WO 2019 / 018736 (published Jan. 24, 2019 and titled “Flexible Elongate Device Systems and Methods”), which is incorporated by reference herein in its entirety.

[0104] In examples where the elongate device 802 and / or medical tool 826 are actuated by a teleoperational assembly (e.g., the manipulator assembly 702), the drive unit 804 may include drive inputs that removably couple to and receive power from drive elements, such as actuators, of the teleoperational assembly. In some examples, the elongate device 802 and / or medical tool 826 may include gripping features, manual actuators, or other components for manually controlling the motion of the elongate device 802 and / or medical tool 826. The elongate device 802 may be steerable or, alternatively, the elongate device 802 may be nonsteerable with no integrated mechanism for operator control of the bending of distal end 818. In some examples, one or more channels 821 (which may also be referred to as lumens), through which medical tools 826 can be deployed and used at a target anatomical location, may be defined by the interior walls of the flexible body 816 of the elongate device 802.

[0105] In some examples, the medical instrument system 800 (e.g., the elongate device 802 or medical tool 826) may include a flexible bronchial instrument, such as a bronchoscope or bronchial catheter, e.g., for use in visual examination and diagnosis, biopsy, and / or treatment of a lung. The medical instrument system 800 may also be suited for navigation and treatment of other tissues, via natural or surgically created connected passageways, in any of a variety of anatomic systems, including the colon, the intestines, the kidneys and kidney calices, the brain, the heart, the circulatory system including vasculature, and / or the like.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC

[0106] The information from the tracking system 830 may be sent to the navigation system 832, where the information may be combined with information from the visualization system 831 and / or pre-operatively obtained models to provide the physician, clinician, surgeon, or other operator with real-time position information. The tracking system 830, the navigation system 832, and the visualization system 831 may cooperatively implement, at least partially, the functionality of the system 100 in implementing the techniques described above. In some examples, the real-time position information may be displayed on the display system 710 for use in the control of the medical instrument system 800. In some examples, the navigation system 832 may utilize the position information as feedback for positioning medical instrument system 800.

[0107] FIGS. 9 A and 9B are simplified diagrams of side views of a patient coordinate space including a medical instrument mounted on an insertion assembly according to some examples. As shown in FIGS. 9 A and 9B, a surgical environment 900 may include the patient P positioned on the patient table T. Patient P may be stationary within the surgical environment 900 in the sense that gross patient movement is limited by sedation, restraint, and / or other means. Cyclic anatomic motion, including respiration and cardiac motion, of patient P may continue. Within surgical environment 900, a medical instrument 904 is used to perform a medical procedure which may include, for example, surgery, biopsy, ablation, illumination, irrigation, suction, or electroporation. The medical instrument 904 may also be used to perform other types of procedures, such as a registration procedure to associate the position, orientation, and / or pose data captured by the sensor system 708 to a desired (e.g., anatomical or system) reference frame. The medical instrument 904 may be, for example, the medical instrument 704. In some examples, the medical instrument 904 may include an elongate device 910 (e.g., a catheter) coupled to an instrument body 912. Elongate device 910 includes one or more channels sized and shaped to receive a medical tool.

[0108] Elongate device 910 may also include one or more sensors (e.g., components of the sensor system 708). In some examples, a shape sensor 914 may be fixed at a proximal point 916 on the instrument body 912. The proximal point 916 of the shape sensor 914 may be movable with the instrument body 912, and the location of the proximal point 916 with respect to a desired reference frame may be known (e.g., via a tracking sensor or other tracking device). The shape sensor 914 may measure a shape from the proximal point 916 to another point, such as a distal end 918 of the elongate device 910. The shape sensor 914 may be aligned with the elongate device 910 (e.g., provided within an interior channel or mountedIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC externally). In some examples, the shape sensor 914 may optical fibers used to generate shape information for the elongate device 910.

[0109] In some examples, position sensors (e.g., EM sensors) may be incorporated into the medical instrument 904. A series of position sensors may be positioned along the flexible elongate device 910 and used for shape sensing. Position sensors may be used alternatively to the shape sensor 914 or with the shape sensor 914, such as to improve the accuracy of shape sensing or to verify shape information.

[0110] Elongate device 910 may house cables, linkages, or other steering controls that extend between the instrument body 912 and the distal end 918 to controllably bend the distal end 918. In some examples, at least four cables are used to provide independent up-down steering to control a pitch of distal end 918 and left-right steering to control a yaw of distal end 918. The instrument body 912 may include drive inputs that removably couple to and receive power from drive elements, such as actuators, of a manipulator assembly.

[0111] The instrument body 912 may be coupled to an instrument carriage 906. The instrument carriage 906 may be mounted to an insertion stage 908 that is fixed within the surgical environment 900. Alternatively, the insertion stage 908 may be movable but have a known location (e.g., via a tracking sensor or other tracking device) within surgical environment 900. Instrument carriage 906 may be a component of a manipulator assembly (e.g., manipulator assembly 702) that couples to the medical instrument 904 to control insertion motion (e.g., motion along an insertion axis A) and / or motion of the distal end 918 of the elongate device 910 in multiple directions, such as yaw, pitch, and / or roll. The instrument carriage 906 or insertion stage 908 may include actuators, such as servomotors, that control motion of instrument carriage 906 along the insertion stage 908.

[0112] A sensor device 920, which may be a component of the sensor system 708, may provide information about the position of the instrument body 912 as it moves relative to the insertion stage 908 along the insertion axis A. The sensor device 920 may include one or more resolvers, encoders, potentiometers, and / or other sensors that measure the rotation and / or orientation of the actuators controlling the motion of the instrument carriage 906, thus indicating the motion of the instrument body 912. In some examples, the insertion stage 908 has a linear track as shown in FIGS. 9A and 9B. In some examples, the insertion stage 908 may have curved track or have a combination of curved and linear track sections.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC

[0113] FIG. 6A shows the instrument body 912 and the instrument carriage 906 in a retracted position along the insertion stage 908. In this retracted position, the proximal point 916 is at a position L0 on the insertion axis A. The location of the proximal point 916 may be set to a zero value and / or other reference value to provide a base reference (e.g., corresponding to the origin of a desired reference frame) to describe the position of the instrument carriage 906 along the insertion stage 908. In the retracted position, the distal end 918 of the elongate device 910 may be positioned just inside an entry orifice of patient P. Also in the retracted position, the data captured by the sensor device 920 may be set to a zero value and / or other reference value (e.g., 1=0). In FIG. 6B, the instrument body 912 and the instrument carriage 906 have advanced along the linear track of insertion stage 908, and the distal end 918 of the elongate device 910 has advanced into patient P. In this advanced position, the proximal point 916 is at a position LI on the insertion axis A. In some examples, the rotation and / or orientation of the actuators measured by the sensor device 920 indicating movement of the instrument carriage 906 along the insertion stage 908 and / or one or more position sensors associated with instrument carriage 906 and / or the insertion stage 908 may be used to determine the position LI of the proximal point 916 relative to the position L0. In some examples, the position LI may further be used as an indicator of the distance or insertion depth to which the distal end 918 of the elongate device 910 is inserted into the passageway(s) of the anatomy of patient P.

[0114] One or more components of the examples discussed in this disclosure, such as system 100, may be implemented in software for execution on one or more processors of a computer system. The software may include code that when executed by the one or more processors, configures the one or more processors to perform various functionalities as discussed herein. The code may be stored in a non-transitory computer readable storage medium (e.g., a memory, magnetic storage, optical storage, solid-state storage, etc.). The computer readable storage medium may be part of a computer readable storage device, such as an electronic circuit, a semiconductor device, a semiconductor memory device, a read only memory (ROM), a flash memory, an erasable programmable read only memory (EPROM); a floppy diskette, a CD-ROM, an optical disk, a hard disk, or other storage device. The code may be downloaded via computer networks such as the Internet, Intranet, etc. for storage on the computer readable storage medium. The code may be executed by any of a wide variety of centralized or distributed data processing architectures. The programmed instructions of the code may be implemented as a number of separate programs or subroutines, or they mayIntuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC be integrated into a number of other aspects of the systems described herein. The components of the computing systems discussed herein may be connected using wired and / or wireless connections. In some examples, the wireless connections may use wireless communication protocols such as Bluetooth, near-field communication (NFC), Infrared Data Association (IrDA), home radio frequency (HomeRF), IEEE 802.11, Digital Enhanced Cordless Telecommunications (DECT), and wireless medical telemetry service (WMTS).

[0115] Various general-purpose computer systems may be used to perform one or more processes, methods, or functionalities described herein. Additionally or alternatively, various specialized computer systems may be used to perform one or more processes, methods, or functionalities described herein. In addition, a variety of programming languages may be used to implement one or more of the processes, methods, or functionalities described herein.

[0116] While certain examples and examples have been described above and shown in the accompanying drawings, it is to be understood that such examples and examples are merely illustrative and are not limited to the specific constructions and arrangements shown and described, since various other alternatives, modifications, and equivalents will be appreciated by those with ordinary skill in the art.

Claims

Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC WHAT IS CLAIMED IS:

1. A system for providing rotation speed feedback during an imaging event, the system comprising:one or more processors; andone or more non-transitory, computer-readable media storing instructions that, when executed by the one or more processors, cause the system to:receive, from an imaging device included in a rotating platform, a plurality of frames of image data depicting a subject at a plurality of different rotation angles;identify a plurality of reference points in an initial frame of image data;determine respective optical displacements of the plurality of reference points across frames of image data of the plurality of frames of image data;based on the respective optical displacements, determine a rotation speed of the rotating platform; andresponsive to determining the rotation speed, cause a speed indicator providing an indication of the rotation speed to be displayed on a display device.

2. The system of claim 1, wherein the rotating platform comprises a C-arm of a fluoroscopic imaging device.

3. The system of claim 1, wherein the plurality of reference points include fiducial markings.

4. The system of claim 3, wherein the fiducial markings are included on a fiducial board.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC 5. The system of claim 4, further comprising instructions that, when executed by the one or more processors, cause the system to:determine respective diameters of the fiducial markings; andscale the optical displacements based on the respective diameters.

6. The system of claim 4, further comprising instructions that, when executed by the one or more processors, cause the system to:determine, based upon a distribution of the fiducial markings on the fiducial board in one or more image frames, that a rotation angle of the imaging device has a field of view proximate to an edge of the fiducial board; andbased upon the rotation angle of the imaging device having the field of view proximate to the edge of the fiducial board, cause a notification to be displayed on the display device.

7. The system of claim 1, wherein the plurality of reference points include points derived from anatomical structures depicted in the plurality of frames of image data.

8. The system of claim 7, wherein the anatomical structures are bony structures.

9. The system of claim 1, wherein:the speed indicator includes a binary speed indicator; andproviding the indication includes determining whether the rotation speed exceeds a threshold rotation speed.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC 10. The system of claim 9, wherein the threshold rotation speed corresponds to a rotation speed at which artifacts are introduced in the depiction of the subject in the plurality of frames of image data.

11. The system of claim 1 , wherein:the speed indicator includes a multi-segment speed indicator, andeach segment of the multi-segment speed indicator is associated with a respective range of rotation speeds.

12. The system of claim 1, wherein to provide the indication of the rotation speed, the instructions, when executed by the one or more processors, cause the system to:determine that the rotation speed is below a threshold speed below which the subject is exposed to unnecessary radiation; andprovide an indication that the rotation speed is too slow.

13. The system of claim 1, further comprising instructions that, when executed by the one or more processors, cause the system to:determine a new set of respective optical displacements across the frames of image data as new frames of image data are received.

14. The system of claim 13, wherein the rotation speed is determined within 30 milliseconds of receiving a new frame of image data.

15. The system of any one of claims 1-14, wherein to determine the rotation speed, the instructions, when executed by the one or more processors, cause the system to:Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC determine the rotation speed based on a combination of rotation speeds determined responsive to receiving a predetermined number of prior frames of image data.

16. The system of claim 15, wherein to combine the rotation speeds determined responsive to receiving the predetermined number of prior frames, the instructions, when executed by the one or more processors, cause the system to:determine an exponential moving average of the rotation speeds determined responsive to the predetermined number of prior frames.

17. The system of any one of claims 1-14, wherein to determine respective optical displacements, the instructions, when executed by the one or more processors, cause the system to:determine a sparse optical flow using a Lucas-Kanade method.

18. The system of any one of claims 1-14, wherein to determine respective optical displacements, the instructions, when executed by the one or more processors, cause the system to:perform outlier removal with respect to the respective optical displacements.

19. The system of any one of claims 1-14, further comprising instructions that, when executed by the one or more processors, cause the system to:determine that a frame of image data does not include a threshold number of reference points; andresponsive to the determination, apply a dense optical flow tracking algorithm.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC 20. The system of any one of claims 1-14, further comprising instructions that, when executed by the one or more processors, cause the system to:detect that a frame of image data is associated with a determined rotation speed exceeding a threshold rotation speed;determine a rotation angle associated with the frame of image data; andcause the display device to display an indication to rotate the rotating platform in a direction to capture a new frame of image data associated with the rotation angle.

21. The system of any one of claims 1-14, further comprising instructions that, when executed by the one or more processors, cause the system to:obtain a reference rotation speed associated with a particular rotation angle from the rotating platform;determine a variance metric between the reference rotation speed and determined rotation speed; andadjust a correspondence between the optical displacements and rotation speed based upon the variance metric.

22. The system of any one of claims 1-14, wherein to determine respective optical displacements of the plurality of reference points across the frames of image data, the instructions, when executed by the one or more processors, cause the system to:track the plurality of reference points across sequential frames of image data.

23. The system of any one of claims 1-14, further comprising instructions that, when executed by the one or more processors, cause the system to:Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC reconstruct a model of the subject by performing tomosynthesis based upon the plurality of frames of image data.

24. A computer-implemented method for providing rotation speed feedback during an imaging event, the computer-implemented method comprising:receiving, via one or more processors and from an imaging device included in a rotating platform, a plurality of frames of image data depicting a subject disposed with an axis of rotation of the rotating platform;identifying, via the one or more processors, a plurality of reference points in an initial frame of image data;determining, via the one or more processors, respective optical displacements of the plurality of reference points across frames of image data of the plurality of frames of image data;based on the respective optical displacements, determining, via the one or more processors, a rotation speed of the rotating platform; andresponsive determining the rotation speed, causing, via the one or more processors, a speed indicator providing an indication of the rotation speed to be displayed on a display device.

25. The computer-implemented method of claim 24, wherein the rotating platform comprises a C-arm of a fluoroscopic imaging device.

26. The computer-implemented method of claim 24, wherein the plurality of reference points include fiducial markings.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC 27. The computer-implemented method of claim 26, wherein the fiducial markings are included on a fiducial board.

28. The computer-implemented method of claim 27, further comprising:determining, via the one or more processors, respective diameters of the fiducial markings; andscaling, via the one or more processors, the optical displacements based on the respective diameters.

29. The computer-implemented method of claim 27, further comprising:determining, via the one or more processors based upon a distribution of the fiducial markings on the fiducial board in one or more image frames, that a rotation angle of the imaging device has a field of view proximate to an edge of the fiducial board; andbased upon the rotation angle of the imaging device having the field of view proximate to the edge of the fiducial board, causing, via the one or more processors, a notification to be displayed on the display device.

30. The computer-implemented method of claim 24, wherein the plurality of reference points include points derived from anatomical structures depicted in the plurality of frames of image data.

31. The computer-implemented method of claim 30, wherein the anatomical structures are bony structures.

32. The computer-implemented method of claim 24, wherein:Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC the speed indicator includes a binary speed indicator; andproviding the indication includes determining whether the rotation speed exceeds a threshold rotation speed.

33. The computer-implemented method of claim 32, wherein the threshold rotation speed corresponds to a rotation speed at which artifacts are introduced in the depiction of the subject in the plurality of frames of image data.

34. The computer-implemented method of claim 24, wherein:the speed indicator includes a multi-segment speed indicator, andeach segment of the multi-segment speed indicator is associated with a respective range of rotation speeds.

35. The computer-implemented method of claim 24, wherein providing the indication of the rotation speed comprises:determining, via the one or more processors, that the rotation speed is below a threshold speed below which the subject is exposed to unnecessary radiation; andproviding, via the one or more processors, an indication that the rotation speed is too slow.

36. The computer-implemented method of claim 24, further comprising:determining, via the one or more processors, a new set of respective optical displacements across the frames of image data as new frames of image data are received.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC 37. The computer-implemented method of claim 36, wherein the rotation speed is determined within 30 milliseconds of receiving a new frame of image data.

38. The computer-implemented method of any one of claims 24-37, wherein determining the rotation speed comprises:determining, via the one or more processors, the rotation speed based on a combination of rotation speeds determined responsive to receiving a predetermined number of prior frames of image data.

39. The computer-implemented method of claim 38, wherein combining the rotation speeds determined responsive to the receiving the predetermined number of prior frames comprises:determining, via the one or more processors, an exponential moving average of the rotation speeds determined responsive to the predetermined number of prior frames.

40. The computer-implemented method of any one of claims 24-37, wherein determining respective optical displacements comprises:determining, via one or more processors, a sparse optical flow using a Lucas-Kanade method.

41. The computer-implemented method of any one of claims 24-37, wherein determining respective optical displacements comprises:performing, via the one or more processors, outlier removal with respect to the respective optical displacements.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC 42. The computer-implemented method of any one of claims 24-37, further comprising:determining, via the one or more processors, that a frame of image data does not include a threshold number of reference points; andresponsive to the determination, applying, via the one or more processors, a dense optical flow tracking algorithm.

43. The computer-implemented method of any one of claims 24-37, further comprising:detecting, via the one or more processors, that a frame of image data is associated with a determined rotation speed exceeding a threshold;determining, via the one or more processors, a rotation angle associated with the frame of image data; andcausing, via the one or more processors, the display device to display an indication to rotate the rotating platform to capture a new frame of image data associated with the rotation angle.

44. The computer-implemented method of any one of claims 24-37, further comprising:obtaining, via the one or more processors, a reference rotation speed associated with a particular rotation angle from the rotating platform;determining, via the one or more processors, a variance metric between the reference rotation speed and determined rotation speed; andadjusting, via the one or more processors, a correspondence between the optical displacements and rotation speed based upon the variance metric.Intuitive Docket No.: P07001-WO Attorney Docket No.: 33685 / 70526 / PC 45. The computer-implemented method of any one of claims 24-37, wherein determining respective optical displacements of the plurality of reference points across the frames of image data comprises:tracking, via the one or more processors, the plurality of reference points across sequential frames of image data.

46. The computer-implemented method of any one of claims 24-37, further comprising:reconstructing, via the one or more processors, a model of the subject by performing tomosynthesis based upon the plurality of frames of image data.

47. A tangible, non-transitory, computer readable medium storing instructions that, when executed by one or more processors, cause the one or more processors to perform the method of any one of claims 24-46.

Images