Methods for improving markerless motion analysis

Abstract

Systems, methods, and computer readable storage devices for improving markerless motion analysis are disclosed. One method comprises receiving position data of body joint centers during motion captured by at least one camera, enhancing three-dimensional (3D) angular kinematic data of the position data of the body joint centers using model equations, the enhanced 3D angular kinematic data including improved measurement accuracy of the position data of the body joint centers, and providing the enhanced 3D angular kinematic data for display to evaluate motion performance.

Description

[Technical field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 150,511, filed February 17, 2022 as a PCT International Patent Application and U.S. Provisional Patent Application No. 63 / 150,511, filed February 17, 2021 (Method for Improving Markerless Motion Analyses), the subject matter of which is incorporated herein by reference.

[0002] The present invention relates generally to methods, systems and computer-readable media for providing physical movement training and instruction using markerless motion analysis, and more particularly, to a computer-implemented system for providing improved markerless motion analysis for athletic training and instruction. [Background technology]

[0003] Many different techniques have been implemented to teach proper motion mechanics for sports, such as swinging a golf club or bat. Currently, instructors, such as professional golfers, use image and / or video analysis systems to teach the proper swing of a golf club. Using a typical video or image analysis system, a golf swing is captured by an imaging device, such as a camera and / or a video recording device. The instructor plays back the recorded image and / or video information to explain the golf swing while providing feedback on the swing. The instructional feedback may be comments regarding problems associated with the swing, compliments regarding swing improvements, suggestions regarding swing modifications, and / or any other verbal instructional comments related to the swing. Visualizing an individual's golf swing in this manner has been recognized as a valuable tool for identifying problems and correcting those problems to improve the overall golf swing.

[0004] Although image and / or video analysis systems are widely used by sports experts such as professional golfers, baseball players, etc., these systems have certain drawbacks. One particular drawback relates to the fact that these systems need to identify human poses and spatial landmarks. For example, an expert needs to subjectively analyze image and / or video information to identify human poses and spatial landmarks. However, typical images and videos alone may not capture enough information in cases of different camera angles, few cameras, loose clothing, etc. Thus, the expert may be forced to infer human pose and spatial landmark information. Thus, the human pose and spatial landmark information identified by the expert may be inaccurate, since it is difficult to separate the swing mechanics and measurements from the images and / or videos.

[0005] To overcome the shortcomings associated with typical image and / or video analysis systems, a motion analysis system may require a user to wear markers and / or sensor elements on the body and the markers and / or sensor elements transmit position data of isolated body parts, such as hands, hips, shoulders and head. The isolated points on the body are measured during the swing according to an absolute reference system, such as a Cartesian coordinate system whose center point is a fixed point in the room. The use of motion analysis can provide accurate measurements to more accurately determine problems during the swing.

[0006] A drawback of such marker-based image and / or video systems is that they require the user to wear the markers and may require precise positioning of the camera and / or video equipment. Thus, the development of marker-free motion capture systems / methods has been motivated by a wide range of athletic and clinical applications.

[0007] However, the use of markerless motion capture to achieve three-dimensional / three-axis (3D) rotational movement (angular kinematics) is limited due to the limited set of spatial coordinates provided by standard markerless motion capture methods. It is with respect to these and other considerations that the present application has been made. Summary of the Invention [Problem to be solved by the invention]

[0008] According to certain embodiments, a system, method, and computer-readable medium for improving markerless motion analysis are disclosed. [Means for solving the problem]

[0009] According to certain embodiments, a computer-implemented method for improving markerless motion analysis is disclosed, comprising: receiving position data of body joint centers during motion captured by at least one camera; enhancing three-dimensional (3D) angular kinematic data of the position data of the body joint centers using model equations, the enhanced 3D angular kinematic data including improved measurement accuracy of the position data of the body joint centers; and providing the enhanced 3D angular kinematic data for display to evaluate motion performance.

[0010] According to certain embodiments, a system for improving markerless motion analysis is disclosed. One system includes a data storage device storing instructions for improving markerless motion analysis, and a processor configured to execute the instructions to perform a method comprising: receiving position data of body joint centers during motion captured by at least one camera, enhancing three-dimensional (3D) angular kinematic data of the position data of the body joint centers using model equations, the enhanced 3D angular kinematic data including improved measurement accuracy of the position data of the body joint centers, and providing the enhanced 3D angular kinematic data for display to evaluate motion performance.

[0011] According to certain embodiments, a non-transitory computer-readable storage device is disclosed that stores instructions that, when executed by a computer, cause the computer to perform a method for improving markerless motion analysis. One method of the computer-readable medium comprises receiving position data of body joint centers during motion captured by at least one camera, enhancing three-dimensional (3D) angular kinematic data of the position data of the body joint centers using model equations, the enhanced 3D angular kinematic data including improved measurement accuracy of the position data of the body joint centers, and providing the enhanced 3D angular kinematic data for display to evaluate motion performance.

[0012] Other objects and advantages of the disclosed embodiments will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the disclosed embodiments. The objects and advantages of the disclosed embodiments will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

[0013] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosed embodiments as claimed. [Brief description of the drawings]

[0014] In the course of the following detailed description, reference will be made to the accompanying drawings, in which: The drawings illustrate different aspects of the present disclosure, and where appropriate, reference numerals designating like structures, components, materials and / or elements in different figures are similarly labeled. It will be understood that various combinations of structures, components and / or elements other than those specifically shown are contemplated and are within the scope of the present disclosure.

[0015] Furthermore, there are many embodiments of the present disclosure described and illustrated herein. The present disclosure is not limited to a single aspect or embodiment thereof, nor to combinations and / or permutations of such aspects and / or embodiments. Furthermore, each of the aspects of the present disclosure and / or embodiments thereof may be employed alone or in combination with one or more of the other aspects and / or embodiments of the present disclosure. For the sake of brevity, certain permutations and combinations are not separately discussed and / or illustrated herein.

[0016] [Figure 1] FIG. 1 illustrates one embodiment of a proposed method for performing markerless motion analysis according to an embodiment of the present disclosure and a golf swing performance as an example of a best mode embodiment.

[0017] [Diagram 2] FIG. 2 illustrates a method for deriving a body segment coordinate system for computing 3D angular kinematics from a limited set of body reference coordinates according to an embodiment of the present disclosure.

[0018] [Diagram 3] FIG. 3 illustrates a process for providing accurate 3D angle measurements using markerless motion capture according to an embodiment of the present disclosure.

[0019] [Figure 4] FIG. 4 illustrates a kinematic enhancement method for improving the accuracy of 3D angle measurements using markerless motion capture according to an embodiment of the present disclosure.

[0020] [Diagram 5] FIG. 5 illustrates a method for improving markerless motion analysis according to an embodiment of the present disclosure.

[0021] [Figure 6] FIG. 6 illustrates a high-level diagram of an exemplary computing device that may be used in accordance with the systems, methods, and computer-readable media disclosed herein, in accordance with embodiments of the present disclosure.

[0022] [Figure 7] FIG. 7 illustrates a high-level diagram of an exemplary computing system that may be used in accordance with the systems, methods, and computer-readable media disclosed herein in accordance with embodiments of the present disclosure.

[0023] Again, there are many embodiments described and illustrated herein. The present disclosure is not limited to any single aspect and / or embodiment thereof, nor to any combination and / or permutation of such aspects and / or embodiments. Each of the aspects and / or embodiments of the present disclosure may be employed alone or in combination with one or more of the other aspects and / or embodiments of the present disclosure. For the sake of brevity, many of these combinations and permutations are not discussed separately herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Those skilled in the art will recognize that various implementations and embodiments of the present disclosure may be implemented in accordance with this specification, and all of these implementations and embodiments are intended to be included within the scope of the present disclosure.

[0025] As used herein, the terms "comprises," "has," "has," "includes," "including," or other variations are intended to cover the non-exclusive inclusion of a process, method, article, or apparatus that comprises a list of elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus, rather than including only those elements. The term "exemplary" is used in the sense of "example" rather than "ideal." Furthermore, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." That is, unless otherwise specified or clear from the context, the phrase "X employs A or B" is intended to mean any of the natural inclusive permutations. For example, the phrase "X employs A or B" is satisfied by either "X employs A," "X employs B," or "X employs both A and B." Furthermore, the articles "a" and "an," as used in this application and the appended claims, should be construed generally to mean "one or more," unless otherwise specified or clear from the context to mean the singular form.

[0026] For the sake of brevity, prior art regarding the systems and servers used to implement the methods and other functional aspects of the systems and servers (and their individual operating components) may not be described in detail herein. Moreover, the connecting lines shown in the various figures contained herein are intended to represent example functional relationships and / or physical couplings between the various elements. It should be noted that many alternative and / or additional functional relationships or physical couplings may exist in the subject embodiments.

[0027] Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0028] In particular, the present disclosure relates to a method for estimating three-dimensional spatial segment orientation of one or more segments when the one or more segments are poorly defined using available spatial reference point data.

[0029] Referring now to the drawings, Figure 1 illustrates an environment 100 for performing enhanced motion analysis according to an embodiment of the present disclosure. As shown in Figure 1, the environment 100 includes an image and / or video analysis system 102 that uses cameras and / or video recording devices 104 to record physical motion process information captured by one or more cameras and / or video recording devices 104. The image and / or video analysis system 102 may capture and / or calculate position information. The image and / or video analysis system 102 processes the data to generate analysis or teaching information that may be used in golf swing analysis and training.

[0030] Although the environment 100 is described below as a system and method for providing golf swing analysis, the image and / or video analysis system 102 may be used to provide motion analysis in other sports, such as baseball, tennis, cricket, polo, or any other sport in which motion is the measure by which an element of the sport is performed. Additionally, the analysis may similarly be used to provide most forms of body motion analysis. Additionally, although the environment 100 depicts two cameras 104, a single camera or a single video recording device may be used.

[0031] In embodiments of the present disclosure, measurement accuracy can be critical, and accurate motion capture has been improved through the development of image processing algorithms and body models that simulate anatomical constraints to enhance detection, tracking, and spatial transformation of skeletal segments and joint centers across successive digital images. The development of markerless motion capture systems has found widespread application in sports and clinical settings, where optical systems are employed to identify human pose and spatial landmarks.

[0032] However, limitations of markerless motion capture to realize 3D / 3-axis rotational motion (angular kinematics) may persist due to the limited set of spatial coordinates provided by markerless motion capture methods. Complex multibody kinematics may be realized by two or more segments mechanically constrained with joints that allow 3D rotation between adjacent segments (as demonstrated in human motion). According to the coupling axioms of Hilbert's foundations of geometry, a plane can be defined in 3D space (Euclidean) by three non-collinear points. This condition allows an analytically defined coordinate system to create a body-fixed reference frame for segment orientation measurements. When spatial coordinates of three non-collinear body-fixed points per segment are not available, alternative approaches may be used to approximate the 3D measurements.

[0033] A partial set of 3D angular kinematics may be provided during a movement task performed slowly in a specific 2D plane of motion, such as squatting or walking. Despite such limitations of motion capture, large angular deviations may be demonstrated when compared to concurrent measurements determined from a marker-based motion analysis system. As mentioned above, marker-based motion analysis systems attach markers directly to bony prominences with established and verified reliability to minimize displacement from anatomical landmarks during dynamic activities.

[0034] However, the identification of landmark points (keypoints) in markerless systems may rely on probabilistic and non-deterministic feature detection that can be highly sensitive to environmental conditions (lighting, obstacles / clothing, pose), resulting in random position errors where the reported landmark coordinates deviate randomly from the true landmark locations. When attempting to use these points to define a planar (2D) reference frame for motion measurement, the random position error variance occurring at each of the keypoints may result in compounded errors between frames of a sequence of images. Furthermore, keypoint position errors may propagate through analytically defined reference geometries at each of the frames, resulting in erroneous deviations. In addition to factors that directly affect keypoint position errors, keypoint-derived reference frame errors may be influenced and compounded / magnified by the keypoint locations of segments, which may affect the shape of the segments and the size of the reference frame using markerless keypoints. Considering the potential errors, various methods, described later, may be used to mitigate their impact on position errors.

[0035] Methods can be employed to measure 2D angular kinematics referenced from the 3D coordinates of three non-adjacent joint centers (i.e., hip, shoulder, elbow, etc.) where relatively consistent patterns of movement occur between markerless and marker-based systems. Similar patterns of movement with sustained large angular deviations have prompted surrogate measurements of rotational movements to provide valid performance measurements using markerless motion capture. Furthermore, the accuracy of angular kinematic measurements has been improved by combining a musculoskeletal body model with anatomical constraints.

[0036] However, despite these approaches, transverse plane rotational motion, in which a body segment twists away from the camera's 2D viewing plane, may rarely be extracted and reported. Although a larger camera set may improve a markerless motion capture system's ability to properly track 3D joint center positions during twisting tasks, transverse plane angular motion may be difficult to extract accurately and reliably.

[0037] A limitation of markerless motion capture techniques may be the number of body reference spatial coordinates available to measure 3D angular kinematics. As explained in more detail below, measurements may require three reference points on a body segment to define a local 3D coordinate system. The 3D spatial orientation of one body segment relative to another body segment is physically quantified as the relative rotational difference between the two 3D coordinate systems. Measurement of the 3D spatial orientation of a body segment (rigid body) requires defining the 3D coordinate system of the rigid body of interest relative to a global 3D coordinate system (reference frame). To define a 3D body-fixed reference frame, at least three independent spatial coordinates that are not collinear and fixed within the reference frame need to be known. This geometric requirement may not be met by markerless motion capture and therefore may prevent analytical methods from quantifying 3D spatial orientation with insufficient / undetermined body segment coordinate data.

[0038] To improve markerless motion capture technology, embodiments of the present disclosure provide a new analytical method for measuring 3D angular kinematics from a constrained body system that can be a useful tool in analyzing torsional motion for performance (i.e., golf swing) and injury risk (i.e., knee injury). Increasing the number of cameras used in markerless motion capture may improve the accuracy of the body-referenced coordinates, but increasing the number of cameras may not improve the computational requirements to provide valid and reliable 3D angular motion measurements. Thus, approaches to improve the practicality of markerless motion capture technology are detailed below.

[0039] The present disclosure relates to a method for providing and improving 3D motion analysis using markerless motion capture techniques having at least one camera, such as a single camera. Embodiments of the present disclosure provide a method for estimating the 3D spatial orientation of one or more rigid bodies, which may occur due to unexplained / random measurement variance when fewer than three body-fixed reference points for each segment are known and / or when these points are not rigidly fixed to the body.

[0040] In an embodiment of the present disclosure, a method is provided that allows estimation of the 3D spatial orientation of one or more rigid bodies by (1) using available spatial information, such as but not limited to, two or more points of at least two directly or indirectly kinematically constrained segments to realize a dependent segment reference frame that utilizes additional constraints that complement the details provided by directly observable body fixed points, and (2) applying a probabilistic mapping of the geometric relationship between one or more body fixed points and one or more systematic kinematic constraints to the 3D body fixed reference frame. The process utilizes direct measurements from a kinematically constrained body fixed coordinate system to realize an indirect representation of the kinematics of the multibody system. Although the measurements track the dependent reference frame, the measurements reflect the net effect of the constrained multibody system kinematics. In other words, one can consider a kinematic constraint centroid that serves as a third body fixed point shared by both segments. Thus, a representative sample of the kinematically constrained measurements may be paired with corresponding validated reference measurements of diagnostically meaningful movements to determine a weighted feature mapping that relates the two sets of measurements. The approaches include, but are not limited to, supervised learning, latent variable models, and constrained kinematics and / or features derived from keypoints.

[0041] As will be described in more detail below, according to an embodiment, a computational method is applied when at least two body fixed points (key points) are known on at least two kinematically constrained rigid bodies (segments) and a global reference frame is defined. Figures 2A-2D show a method for deriving a body segment coordinate system for computing 3D angular kinematics from a limited set of body reference coordinates according to aspects of the present disclosure. In particular, Figures 2A-2D show a method for defining a body segment coordinate system for enabling computation of three-dimensional (3D) angular kinematics when at least two body fixed points on at least two kinematically constrained rigid bodies are known. As shown in Figure 2A, each of segments 202A and 202B has at least two body fixed points (key points) 204A and 204B. Each of the key points 204A and 204B may be based on a reference coordinate system 206 fixed to an inertial frame (global reference frame). For each of Figures 2A-2D, a reference axis is defined. FIG. 2B shows an axis 208 as defined between two body fixed points 204A and 204B of each of the body segments 202A and 202B. The body fixed points 204A and 204B may not include joint constraints shared by the two segments 202A and 202B. A temporary axis 210 may be defined from the midpoint of each of the axes 208 of the (indirectly) adjacent segments 202A and 202B. FIG. 2C shows that an axis 212 may be defined as an axis orthogonal to the segment specific axes 208 and 210. FIG. 2D shows that a final axis 214 may be defined as an axis orthogonal to the axes 208 and 212. This approach provides a frame of reference for each of the segments to capture directional drive interactions where one axis (axis 208) is body fixed and two axes represent systematic constrained joint kinematics between the two segments.

[0042] Measurements taken from a body-axis-fixed reference frame provide a systematic representation including the (constrained) relative spatial orientation between the segments with respect to the global reference frame 206. As explained in more detail below, 3D angular kinematics can be calculated directly according to rules that may be applied assuming an independent body-axis-fixed coordinate system.

[0043] For example, the x-axis and z-axis may be defined as parallel to the floor / ground and perpendicular to each other, and the y-axis may be defined as perpendicular to the x-axis and z-axis and orthogonal to the floor / ground. Alternatively, a reference to the coordinate origin may be defined as specific to the user of the system. The axis system may be used to determine measurements of angular rotation values. For example,

number

number

number

number

number

number

number

Number

Number

[0044] As described above, embodiments of the present disclosure provide a supervised learning approach and / or a machine learning approach that may be used to enhance kinematic data. The approach of the embodiments of the present disclosure may be based on training one or more machine learning approaches to determine a model equation used to enhance kinematic data. More generally discussing machine learning, an example of machine learning may include neural networks including, but not limited to, convolutional neural networks, deep neural networks, recurrent neural networks, etc.

[0045] As will be described in more detail below, the kinematic enhancement procedure may approximate the orientation of a true analytically defined independent body-fixed reference frame with respect to the global reference frame of a specific motion task. This procedure may use a probabilistic mapping determined using measurements from kinematically constrained validation examples of the orientation of independent segments in relation to measurements calculated using an alternative body-fixed interaction reference frame among representative samples of relative orientations. Next, the model equation from the mapping procedure may be used to measure the 3D angular kinematics of a new motion performance. The results may be displayed, for example, on a dashboard of a computer screen, a smart device, etc.

[0046] FIG. 3 illustrates a method 300 for providing accurate 3D angle measurements using markerless motion capture according to an embodiment of the present disclosure. As shown in FIG. 3, an athlete / user / performer may perform an action 302 including a movement of the athlete / user / performer's body. At least one camera, e.g., a single camera, may capture at least two images of the moving body at 304. Image processing may be performed at 306 to output an image having a two-dimensional array of pixels. Camera calibration may then be performed at 308 to generate two-dimensional coordinates of the moving body. A direct linear transformation of the images may then be performed at 310 to generate three-dimensional coordinates of key points of the moving body. For example, the three-dimensional coordinates of the moving body's key points may be three-dimensional joint center locations 312.

[0047] The 3D joint center positions of the body during the movement may be received at 314. As shown at 316 in FIG. 3, the 3D angular kinematics may be calculated directly according to rules applied assuming an independent body-fixed coordinate system. At 318, a kinematic enhancement procedure that approximates the orientation of the true analytically defined independent body-fixed reference frame relative to the global reference frame may be performed for the specific movement task captured by at least one camera. As described in more detail below, this procedure may use a probabilistic mapping determined using measurements of representative examples from a kinematically constrained validation example of the orientation of the independent segments in relation to measurements calculated using an alternative body-fixed interaction reference frame during a representative sample of relative orientations. The model equations from the mapping procedure may be used to measure the 3D angular kinematics of the new movement performance at 320, and at 322, the model equations from the mapping procedure are displayed on a computer screen or smart device dashboard.

[0048] 4 illustrates a kinematic enhancement method for improving the accuracy of 3D angle measurements using markerless motion capture according to an embodiment of the present disclosure. The procedure may begin with receiving / obtaining 402 reference measurements by a data process 403. A probabilistic mapping may be used, which is determined using measurements of representative examples from a kinematically constrained validation example of the orientation of the independent segments in relation to measurements calculated using an alternative body-fixed interaction frame of reference during a representative sample of relative orientations.

[0049] For example, data process 403 may process markerless motion capture data 404 for use in training one or more machine learning approaches. In a representative measurement example of markerless motion capture 404, an athlete / user / performer may perform an action that includes movement of the athlete / user / performer's body. At least one camera, e.g., a single camera, may capture at least two images of the body in motion, 404A. Image processing may be performed, 404B, to output an image having a two-dimensional array of pixels. A calibration of the camera may then be performed, 404C, to generate two-dimensional coordinates of the body in motion. A direct linear transformation of the images may then be performed, 404D, to generate three-dimensional coordinates of key points of the body in motion. The three-dimensional angular kinematics may then be calculated directly, 404E, according to rules that apply assuming an independent body-fixed coordinate system. The three-dimensional angular kinematics are applied to generate rotational data related to the three-dimensional coordinates.

[0050] Furthermore, data process 403 may process marker - based motion capture data 406 used for training one or more machine - learning approaches. For example, in marker - based motion capture, one or more infrared cameras 406A may capture markers placed on a user. By using camera calibration 406B, x - axis coordinates and y - axis coordinates may be extracted from the captured markers. Direct linear transformation 406C may be used to generate three - dimensional coordinates of the x - axis, y - axis, and z - axis from the extracted coordinates. Finally, three - dimensional angular kinematics 406D may be applied to generate rotation data regarding the three - dimensional coordinates.

[0051] In an embodiment of the present disclosure, data process 403 may adopt a motion analysis method and may extract and transform a set of body - reference landmarks (keypoints) from continuous video images of motion performance. The set of keypoints may be limited and may provide a part of the body joint center positions such as the mid - point positions between pairs of keypoints. The keypoints may be received and / or input for generating three - dimensional angular kinematics. Then, probabilistic mapping 408 may be used. During probabilistic mapping, measurements from representative examples of kinematically - constrained validation cases of the orientation of independent segments may be used in relation to measurements calculated using an alternative body - axis - fixed interaction reference frame between representative samples of relative orientation. Probabilistic mapping transformation 408 may provide model equations 410 for increasing the calculation accuracy of 3D angular kinematics.

[0052] The enhanced kinematic data is then passed to a dashboard where relevant task-specific metrics are extracted and displayed numerically and / or graphically on a computer screen or smart device. (See 320 and 322 in FIG. 3). The performance metrics may be used to evaluate motion performance and provide actionable insights. Probabilistic mapping may establish a relationship between the combined constrained reference frame and an analytically defined equivalent reference frame. As described above, this is accomplished by using paired validation examples of the orientations of independent segments in conjunction with measurements calculated using an alternative body-fixed interacting reference frame during a representative sample of relative orientations. Such mapping provides improved quantitative accuracy in measuring 3D angular kinematics from a less constrained / defined set of body-fixed reference positions, advancing markerless motion technology by providing a motion analysis methodology that is not limited to a small set of body reference landmarks to generate accurate 3D angular kinematics.

[0053] The probabilistic mapping may be trained on multiple example datasets to account for variability between measured subjects and / or different measurement setups. Additionally, multiple repositories of multiple example datasets for various sports and functional tasks may exist. These repositories may have been created previously and may be freely available. By using these multiple example datasets, a limited set of keypoints captured by a single camera during markerless motion capture may be used to generate enhanced 3D angular motion data.

[0054] Probabilistic mapping may learn common features of example data sets by training on multiple example data sets. Probabilistic mapping may parameterize relationships between correlated phenomena when analytical solutions are not available. Probabilistic mapping utilizes paired data relating to the inputs and outputs of some mechanism of interest. Approaches to applying probabilistic mapping may include numerical approximation or other function approximation methods applying error metrics that probabilistically constrain outcomes based on likelihood.

[0055] Supervised learning is one application of probabilistic mapping. For example, supervised learning may use an analytical solution to determine position data based on multiple factors / data points from an example data set. Using example pairs of input / output data representing parameters and positions, a function may be approximated that maps position data to 3D angular motion data by minimizing the error of the prediction against the example data. As described above, embodiments of the present disclosure may be used to generate model equations using supervised learning, machine learning, neural networks, etc.

[0056] More generally, the present disclosure may be used to improve various aspects of markerless motion capture, for example through the use of supervised learning or machine learning such as neural networks. In an exemplary embodiment of the present disclosure, the baseline measurements used by the trained neural network may generate a model equation. Thus, the neural network may be fed with values. The neural network may then be trained to directly output the model equation. To train the neural network, the neural network may receive the markerless motion capture data 404 and the marker-based motion capture data 406 as input data.

[0057] FIG. 5 illustrates a method 500 for improving markerless motion analysis according to an embodiment of the present disclosure. The method 500 may begin at step 502, where a neural network model may be constructed, a neural network may be received, and / or model equations may be received directly. The neural network model may have a plurality of neurons. The neural network model may be configured to output the model equations. The plurality of neurons may be arranged in a plurality of layers, including at least one hidden layer, and may be connected by connections. Each of the connections may have a weight. The neural network model may comprise a convolutional neural network model, a deep neural network, or a recurrent neural network.

[0058] If receiving / building a neural network or supervised learning is used to generate the model equations, a training example data set may be received in step 504. The training example data set may include position data of joint centers of the body during motion. By training on the training example data set, the probabilistic mapping may learn features common to the training example data set. The probabilistic mapping may parameterize relationships between correlated phenomena when analytical solutions are not available. The probabilistic mapping utilizes paired data relating to inputs and outputs of some mechanism of interest. Additionally, the received training data set may include data previously captured by a markerless motion capture system and / or a marker-based motion capture system.

[0059] In step 506, a neural network model may be trained or model equations may be generated using the training example data set. Then, in step 508, the trained neural network model / model equations may be output. In step 510, a test data set may be received. Alternatively and / or additionally, a test data set may be created. Then, in step 512, the trained neural network or the output model equations may be tested for evaluation using the test data set. Furthermore, the trained neural network or the output model equations may be utilized if evaluated to exceed a predefined threshold. Furthermore, in certain embodiments of the present disclosure, the steps of method 500 may be repeated to generate multiple model equations. The multiple model equations may be compared to each other. Alternatively, steps 510 and 512 may be omitted.

[0060] The output training neural network model and / or the model equations configured to output the model equations may be received at step 514. Next, at step 516, position data of joint centers of the body in motion captured by the at least one camera may be received. For example, the at least one camera may be a single camera that captures images using markerless motion capture. Alternatively, a single camera may be used to capture a first image and a second image of the body in motion at a first time and a second time different from the first time prior to receiving the position data. Then, the position data of the joint centers of the body in motion may be generated from the images. For example, receiving the position data of the body joint centers may include receiving at least two key points of a first segment of the body in motion and at least two key points of a second segment of the body in motion for at least two separate time points. The key points correspond to positions of parts of the body in motion captured by the at least one camera. From the received position data, a first axis may be defined between at least two key points of each of the segments, a temporal axis may be defined at the midpoint of each of the first axes, a second axis may be defined for each of the segments that is orthogonal to the temporal axis and the first axis of each of the segments, and a third axis may be defined for each of the segments that is orthogonal to the first axis and the second axis. A three-dimensional angular kinematics of the first segment and a three-dimensional angular kinematics of the second segment may then be generated based on the at least two key points of the first segment and the at least two key points of the second segment for at least two distinct time points and the defined first, second and third axes of the key points.

[0061] Then, in step 518, the 3D angular kinematic data of the position data of the joint centers of the body may be enhanced. Enhancing the 3D angular kinematic data may be enhanced using a model equation. As described above, the model equation may be generated based on a probabilistic mapping to enhance the 3D angular kinematic data. The enhanced 3D angular kinematic data includes an increase in the measurement accuracy of the position data of the joint centers of the body. Finally, in 520, the enhanced 3D angular kinematic data may be provided for display to evaluate athletic performance.

[0062] 6 illustrates a high-level diagram of an exemplary computing device 600 that may be used in accordance with the systems, methods, and computer-readable media disclosed herein, according to embodiments of the present disclosure. For example, the computing device 600 may be used in a system that performs methods according to embodiments of the present disclosure. The computing device 600 may have at least one processor 602 that executes instructions stored in a memory 604. The instructions may be, for example, instructions for performing functions described as being performed by one or more components described above or instructions for performing one or more methods described above. The processor 602 may access the memory 604 via a system bus 606. In addition to storing executable instructions, the memory 604 may store data, images, information, event logs, and the like.

[0063] Computing device 600 may further include a data store 608 accessible by processor 602 via system bus 606. Data store 608 may include executable instructions, data, images, information, event logs, etc. Computing device 600 may include an input interface 610 that allows external devices to communicate with computing device 600. For example, input interface 610 may be used to receive instructions from an external computer device, a user, etc. Computing device 600 may include an output interface 612 that allows computing device 600 to interact with one or more external devices. For example, computing device 600 may display text, images, etc. via output interface 612.

[0064] It is contemplated that external devices communicating with computing device 600 via input interface 610 and output interface 612 may be included in the environment to provide most types of user interfaces with which a user can interact. Examples of types of user interfaces include graphical user interfaces, natural user interfaces, etc. For example, a graphical user interface may accept input from a user using input device(s) such as a keyboard, mouse, remote control, etc., and may provide output to an output device such as a display. Furthermore, a natural user interface may enable a user to interact with computing device 600 in a manner free from the constraints imposed by input devices such as a keyboard, mouse, remote control, etc. Rather, a natural user interface may rely on voice recognition, touch and stylus recognition, on-screen and adjacent-screen gesture recognition, air gestures, head and eye tracking, voice and speech, vision, touch, gestures, machine intelligence, etc.

[0065] Additionally, while computing device 600 is illustrated as a single system, it should be understood that computing device 600 may be a distributed system. Thus, for example, multiple devices may be in communication over a network connection and may collectively perform the tasks described as being performed by computing device 600.

[0066] Turning to Figure 7, Figure 7 illustrates a high level diagram of an example computing system 700 that may be used in accordance with the systems, methods, and computer readable media disclosed herein in accordance with embodiments of the present disclosure. For example, computing system 700 may be or may include image and / or video analysis system 102. Additionally and / or alternatively, image and / or video analysis system 102 may be or may include computing system 700.

[0067] The computing system 700 may include multiple server computing devices, such as a server computing device 702 and a server computing device 704 (collectively, server computing devices 702-704). The server computing device 702 may include at least one processor and memory, where the at least one processor executes instructions stored in the memory. The instructions may be, for example, instructions for performing a function described as being performed by one or more components described above or instructions for implementing one or more methods described above. Similar to the server computing device 702, at least a subset of the server computing devices 702-704 other than the server computing device 702 may each include at least one processor and memory. Additionally, at least a subset of the server computing devices 702-704 may include respective data stores.

[0068] The processor(s) of one or more of the server computing devices 702-704 may be or include a processor of the image and / or video analysis system 102. Further, the memory(s) of one or more of the server computing devices 702-704 may be or include a memory of the image and / or video analysis system 702. Further, the data store(s) of one or more of the server computing devices 702-704 may be or include a data store of the image and / or video analysis system 102.

[0069] The computing system 700 may further include various network nodes 706 that transmit data between the server computing devices 702-704. Additionally, the network nodes 706 may transfer data from the server computing devices 702-704 to external nodes (e.g., outside the computing system 700) over a network 708. The network nodes 702 may transfer data from external nodes to the server computing devices 702-704 over the network 708. The network 708 may be, for example, the Internet, a cellular network, etc. The network nodes 706 may include switches, routers, load balancers, etc.

[0070] The fabric controller 710 of the computing system 700 may manage the hardware resources of the server computing devices 702-704 (e.g., the processors, memory, data stores, etc. of the server computing devices 702-704). Additionally, the fabric controller 710 may manage the network nodes 706. Additionally, the fabric controller 710 may manage the creation, provisioning, de-provisioning, and monitoring of managed runtime environments instantiated on the server computing devices 702-704.

[0071] As used herein, the terms "component" and "system" are intended to encompass computer-readable data storage devices comprised of computer-executable instructions that, when executed by a processor, cause a particular function to be performed. The computer-executable instructions may include routines, functions, etc. It should also be understood that a component or system may be localized on a single device or distributed across multiple devices.

[0072] Various functions described herein may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored and / or transmitted as one or more instructions or code on a computer-readable medium. A computer-readable medium may include a computer-readable storage medium. A computer-readable storage medium may be any available storage medium that may be accessed by a computer. By way of non-limiting example, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc as used herein may include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs (BDs), where a disk typically reproduces data magnetically and a disc typically reproduces data optically using a laser. Additionally, propagating signals are not included within the scope of computer-readable storage media. Computer-readable media also includes communication media, including any medium that facilitates transfer of a computer program from one place to another. For example, a connection may be a communication medium. For example, if the software is transmitted from a website, server or other remote source using coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, microwave, etc., coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, microwave, etc., are included within the definition of communication media. Combinations of the above may also be included within the scope of computer-readable media.

[0073] Alternatively and / or additionally, the functions described herein may be performed at least in part by one or more hardware logic components. For example, example types of hardware logic components that may be used include, but are not limited to, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), etc.

[0074] What has been described above includes examples of one or more embodiments. Of course, it is not possible to describe every conceivable variation and modification of the above-described apparatus or methodology in order to describe the aspects described above, but one of ordinary skill in the art can recognize that many further variations and permutations of the various aspects are possible. It is therefore intended that the described aspects include all such variations, modifications and modifications that fall within the scope of the appended claims. The inventions disclosed herein include the following: [Aspect 1] 1. A computer-implemented method for improving markerless motion analysis, comprising: receiving position data of joint centers of a moving body captured by at least one camera; augmenting three-dimensional (3D) angular kinematic data of the position data of the joint centers of the body using a model equation, the augmented 3D angular kinematic data including an improved measurement accuracy of the position data of the joint centers of the body; providing said enhanced 3D angular kinematic data for display to assess athletic performance; and A method for providing the above. [Aspect 2] the at least one camera is a single camera; The method of aspect 1, further comprising using the single camera to capture a first image and a second image of the body during exercise at a first time and a second time different from the first time. [Aspect 3] 3. The method of claim 2, wherein the first image and the second image are captured using markerless motion capture. [Aspect 4] Receiving position data of the body joint centers includes: The method of claim 1, comprising receiving at least two key points of a first segment of the body during motion and at least two key points of a second segment of the body during motion for at least two separate time points, the key points corresponding to positions of portions of the body during motion captured by the at least one camera. [Aspect 5] defining a first axis between the at least two key points of each of the segments; defining temporary axes at the midpoints of each of the first axes; defining, for each of said segments, a second axis orthogonal to said temporal axis and to the first axis of each of said segments; defining a third axis for each of the segments, the third axis being orthogonal to the first axis and the second axis; 5. The method of embodiment 4, further comprising: [Aspect 6] The method of claim 5, further comprising generating a three-dimensional angular kinematics of the first segment and a three-dimensional angular kinematics of the second segment based on at least two key points of the first segment and at least two key points of the second segment for the at least two distinct time points and the defined first axis, second axis and third axis of the key points. [Aspect 7] augmenting the 3D angular kinematics data using the model equations comprises using a neural network model; receiving a plurality of exemplary data sets including a plurality of position data of joint centers of the body during motion; training the neural network model using the plurality of example data sets, the neural network model configured to output the model equation; 2. The method of embodiment 1, further comprising: [Aspect 8] The method of embodiment 7, further comprising: constructing a neural network model including a plurality of neurons configured to output the model equation, the plurality of neurons being arranged in a plurality of layers having at least one hidden layer and connected by a plurality of connections. [Aspect 9] 2. The method of embodiment 1, wherein enhancing the 3D angular kinematic data using the model equation comprises using probabilistic mapping to enhance the 3D angular kinematic data. [Aspect 10] 1. A system for improving markerless motion analysis, comprising: a data storage device storing instructions for improving the markerless motion analysis; receiving position data of joint centers of a moving body captured by at least one camera; augmenting three-dimensional (3D) angular kinematic data of the position data of the joint centers of the body using a model equation, the augmented 3D angular kinematic data including an improved measurement accuracy of the position data of the joint centers of the body; providing said enhanced 3D angular kinematic data for display to assess athletic performance; and A processor configured to execute the instructions to perform a method comprising: A system comprising: [Aspect 11] the at least one camera is a single camera; The method comprises: The system of aspect 10, further comprising using the single camera to capture a first image and a second image of the body during exercise at a first time and a second time different from the first time. [Aspect 12] The system of aspect 11, wherein the first image and the second image are captured using markerless motion capture. [Aspect 13] Receiving position data of the body joint centers includes: The system of aspect 10, further comprising receiving, for at least two separate time points, at least two key points of a first segment of the body during motion and at least two key points of a second segment of the body during motion, the key points corresponding to positions of parts of the body during motion captured by the at least one camera. [Aspect 14] defining a first axis between the at least two key points of each of the segments; defining temporary axes at the midpoints of each of the first axes; defining, for each of said segments, a second axis orthogonal to said temporal axis and to the first axis of each of said segments; defining a third axis for each of the segments, the third axis being orthogonal to the first axis and the second axis; 14. The system of embodiment 13, further comprising: [Aspect 15] The system of aspect 14, further comprising generating a three-dimensional angular kinematics of the first segment and a three-dimensional angular kinematics of the second segment based on at least two key points of the first segment and at least two key points of the second segment for the at least two distinct time points and the defined first axis, second axis and third axis of the key points. [Aspect 16] augmenting the 3D angular kinematics data using the model equations comprises using a neural network model; The method comprises: receiving a plurality of exemplary data sets including a plurality of position data of joint centers of the body during motion; training the neural network model using the plurality of example data sets, the neural network model configured to output the model equation; 11. The system of embodiment 10, further comprising: [Aspect 17] The system of aspect 16, further comprising: constructing a neural network model including a plurality of neurons configured to output the model equation, the plurality of neurons being arranged in a plurality of layers having at least one hidden layer and connected by a plurality of connections. [Aspect 18] The system of aspect 10, wherein enhancing the 3D angular kinematic data using the model equation comprises using probabilistic mapping to enhance the 3D angular kinematic data. [Aspect 19] 1. A non-transitory computer-readable storage device storing instructions that, when executed by a computer, cause the computer to perform a method for improving markerless motion analysis, the method comprising: The method comprises: receiving position data of joint centers of a moving body captured by at least one camera; augmenting three-dimensional (3D) angular kinematic data of the position data of the joint centers of the body using a model equation, the augmented 3D angular kinematic data including an improved measurement accuracy of the position data of the joint centers of the body; providing said enhanced 3D angular kinematic data for display to assess athletic performance; and 13. A computer readable storage device comprising: [Aspect 20] the at least one camera is a single camera; The method comprises: using the single camera to capture a first image and a second image of the body in motion at a first time and a second time different from the first time; The first image and the second image are captured using markerless motion capture. Aspects 20. The computer readable storage device of claim 19.

Claims

1. 1. A computer-implemented method for improving markerless motion analysis, comprising: receiving three-dimensional (3D) position data of spatial landmarks in a body segment coordinate system captured by at least one camera, the 3D position data being insufficient to construct 3D orientation information of at least one segment in the body segment coordinate system, and a linked segment rigid body system having two or more points of at least two directly or indirectly kinematically constrained segments; generating a model equation for the 3D position data by probabilistic mapping; acquiring 3D kinematic data of at least one segment in the body segment coordinate system using the model equations, said acquiring comprising analyzing the two or more points of the at least two directly or indirectly kinematically constrained segments to realize a dependent segment reference frame utilizing additional constraints that complement the details provided by directly observable body fixed points, said 3D kinematic data including 3D orientation information of the at least one segment in the body segment coordinate system; providing said 3D kinematic data for display to assess athletic performance; and A method for providing the above.

2. the at least one camera is a single camera; 2. The method of claim 1, further comprising capturing a first image and a second image of the body segment coordinate system at a first time and a second time different from the first time using the single camera.

3. The method of claim 2 , wherein the first image and the second image are captured using markerless motion capture.

4. Receiving 3D position data of the spatial landmarks includes:

2. The method of claim 1, comprising receiving, for at least two distinct time points, at least two key points of a first segment of the body segment coordinate system and at least two key points of a second segment of the body segment coordinate system, the key points corresponding to positions of portions of the body segment coordinate system captured by the at least one camera.

5. defining a first axis between the at least two key points of each of the segments; defining temporary axes at the midpoints of each of the first axes; defining for each of said segments a second axis orthogonal to said temporal axis and to the first axis of each of said segments; defining a third axis for each of the segments, the third axis being orthogonal to the first axis and the second axis; The method of claim 4 further comprising:

6. 6. The method of claim 5, further comprising generating a three-dimensional angular kinematics of the first segment and a three-dimensional angular kinematics of the second segment based on at least two key points of the first segment and at least two key points of the second segment for the at least two distinct time points and the defined first axis, second axis, and third axis of the key points.

7. The method of claim 1, wherein generating the model equation comprises using a neural network model. Receiving a plurality of exemplary data sets including a plurality of position data of joint centers of the body during motion; training the neural network model using the plurality of example data sets, the neural network model configured to output the model equation; The method of claim 1 further comprising:

8. 8. The method of claim 7, further comprising: constructing a neural network model including a plurality of neurons configured to output the model equation, the plurality of neurons being arranged in a plurality of layers, including at least one hidden layer, and connected by a plurality of connections.

9. The method described in claim 1, wherein obtaining the 3D kinematic data using the model equation comprises using the probabilistic mapping to enhance the 3D kinematic data.

10. 1. A system for improving markerless motion analysis, comprising: a data storage device storing instructions for improving the markerless motion analysis; receiving three-dimensional (3D) position data of spatial landmarks in a body segment coordinate system captured by at least one camera, the 3D position data being insufficient to construct 3D orientation information of at least one segment in the body segment coordinate system, and a linked segment rigid body system having two or more points of at least two directly or indirectly kinematically constrained segments; generating a model equation for the 3D position data by probabilistic mapping; acquiring 3D kinematic data of at least one segment in the body segment coordinate system using the model equations, said acquiring comprising analyzing the two or more points of the at least two directly or indirectly kinematically constrained segments to realize a dependent segment reference frame utilizing additional constraints that complement the details provided by directly observable body fixed points, said 3D kinematic data including 3D orientation information of the at least one segment in the body segment coordinate system; providing said 3D kinematic data for display to assess athletic performance; and A processor configured to execute the instructions to perform a method comprising: A system comprising:

11. the at least one camera is a single camera; The method comprises:

11. The system of claim 10, further comprising: capturing, using the single camera, a first image and a second image of the body segment coordinate system at a first time and a second time different from the first time.

12. The system of claim 11 , wherein the first image and the second image are captured using markerless motion capture.

13. Receiving 3D position data of the spatial landmarks includes:

11. The system of claim 10, further comprising receiving, for at least two distinct time points, at least two key points of a first segment of the body segment coordinate system and at least two key points of a second segment of the body segment coordinate system, the key points corresponding to positions of portions of the body segment coordinate system captured by the at least one camera.

14. defining a first axis between the at least two key points of each of the segments; defining temporary axes at the midpoints of each of the first axes; defining for each of said segments a second axis orthogonal to said temporal axis and to the first axis of each of said segments; defining a third axis for each of the segments, the third axis being orthogonal to the first axis and the second axis; The system of claim 13 further comprising:

15. 15. The system of claim 14, further comprising generating a three-dimensional angular kinematics of the first segment and a three-dimensional angular kinematics of the second segment based on at least two key points of the first segment and at least two key points of the second segment for the at least two distinct time points and the defined first axis, second axis and third axis of the key points.

16. The method of claim 15, wherein generating the model equation comprises using a neural network model. The method comprises: Receiving a plurality of exemplary data sets including a plurality of position data of joint centers of the body during motion; training the neural network model using the plurality of example data sets, the neural network model configured to output the model equation; The system of claim 10 further comprising:

17. 17. The system of claim 16, further comprising: constructing a neural network model including a plurality of neurons configured to output the model equation, the plurality of neurons arranged in a plurality of layers having at least one hidden layer and connected by a plurality of connections.

18. The system of claim 10, wherein obtaining the 3D kinematic data using the model equation comprises using the probabilistic mapping to enhance the 3D kinematic data.

19. 1. A non-transitory computer-readable storage device storing instructions that, when executed by a computer, cause the computer to perform a method for improving markerless motion analysis, the method comprising: The method comprises: receiving three-dimensional (3D) position data of spatial landmarks in a body segment coordinate system captured by at least one camera, the 3D position data being insufficient to construct 3D orientation information of at least one segment in the body segment coordinate system, and a linked segment rigid body system having two or more points of at least two directly or indirectly kinematically constrained segments; generating a model equation for the 3D position data by probabilistic mapping; acquiring 3D kinematic data of at least one segment in the body segment coordinate system using the model equations, said acquiring comprising analyzing the two or more points of the at least two directly or indirectly kinematically constrained segments to realize a dependent segment reference frame utilizing additional constraints that complement the details provided by directly observable body fixed points, said 3D kinematic data including 3D orientation information of the at least one segment in the body segment coordinate system; providing said 3D kinematic data for display to assess athletic performance; and 13. A computer readable storage device comprising:

20. the at least one camera is a single camera; The method comprises: capturing a first image and a second image of the body segment coordinate system at a first time and a second time different from the first time using the single camera; The computer readable storage device of claim 19 , wherein the first image and the second image are captured using markerless motion capture.

Images