scholarly journals Bone Pose Estimation in the Presence of Soft Tissue Artifact Using Triangular Cosserat Point Elements

2015 ◽  
Vol 44 (4) ◽  
pp. 1181-1190 ◽  
Author(s):  
Dana Solav ◽  
M. B. Rubin ◽  
Andrea Cereatti ◽  
Valentina Camomilla ◽  
Alon Wolf
Keyword(s):  
Soft Tissue ◽  
Pose Estimation ◽  
Cosserat Point ◽  
Soft Tissue Artifact

scholarly journals Bone Pose Estimation in the Presence of Soft Tissue Artifact Using Triangular Cosserat Point Elements

2017 ◽  
Author(s):  
Dana Solav ◽  
MB Rubin ◽  
Andrea Cereatti ◽  
Valentina Camomilla ◽  
Alon Wolf
Keyword(s):  
Soft Tissue ◽  
Pose Estimation ◽  
Ex Vivo ◽  
Accurate Estimation ◽  
Relative Rotation ◽  
Kinematic Data ◽  
Cosserat Point ◽  
Position And Orientation ◽  
Soft Tissue Artifact ◽  
Procrustes Superimposition

Accurate estimation of the position and orientation (pose) of a bone from a cluster of skin markers is limited mostly by the relative motion between the bone and the markers, which is known as the Soft Tissue Artifact (STA). This work presents a method, based on continuum mechanics, to describe the kinematics of a cluster affected by STA. The cluster is characterized by Triangular Cosserat Point Elements (TCPEs) defined by all combinations of three markers. The effects of the STA on the TCPEs are quantified using three parameters describing the strain in each TCPE and the relative rotation and translation between TCPEs. The method was evaluated using previously collected ex-vivo kinematic data. Femur pose was estimated from 12 skin markers on the thigh, while its reference pose was measured using bone pins. Analysis revealed that instantaneous subsets of TCPEs exist which estimate bone position and orientation more accurately than the Procrustes Superimposition applied to the cluster of all markers. It has been shown that some of these parameters correlate well with femur pose errors, which suggests that they can be used to select, at each instant, subsets of TCPEs leading an improved estimation of the underlying bone pose.

scholarly journals Soft Tissue Artifact Compensation Using Triangular Cosserat Point Elements (TCPEs)

2017 ◽  
Author(s):  
Dana Solav ◽  
MB Rubin ◽  
Alon Wolf
Keyword(s):  
Soft Tissue ◽  
System Analysis ◽  
Breast Implant ◽  
Rigid Motion ◽  
Body Segment ◽  
Optoelectronic System ◽  
Data Set ◽  
Cosserat Point ◽  
Bony Segment ◽  
Soft Tissue Artifact

Existing methods which compensate for the Soft Tissue Artifact (STA) in optoelectronic motion measurements estimate the rigid motion of a nearly rigid underlying body segment based on analysis of the motion of all fiducial markers. The objective of the proposed Triangular Cosserat Point Elements (TCPE) method is to estimate the motion of the underlying body segment even when the STA in the entire cluster of markers can be large. This is accomplished by characterizing the cluster of markers with TCPEs defined by triangles based on all combinations of three markers. Then, scalar deformation measures characterizing the magnitudes of strain and relative rotation of pairs of TCPEs are defined for each TCPE. These deformation measures are used to define a filtered group of TCPEs which best represents the motion of the underlying body segment. The method was tested using an experimental setup that consists of a rigid pendulum with a deformable 300ml silicone breast implant attached to it as a simulation of the soft tissue around a bony segment. The rotation angles extracted from markers on the deformable implant were compared with simultaneous measurements of the rigid pendulum using an optoelectronic system. Analysis of the experimental data shows that this filtering process substantially reduces the error due to the STA even though the data set includes large deformations. In particular, the analysis shows that the error reduction using the TCPE approach is larger than the reductions obtained using standard least-squares minimization methods.

Can the Effect of Soft Tissue Artifact Be Eliminated in Upper-Arm Internal-External Rotation?

2011 ◽  
Vol 27 (3) ◽  
pp. 258-265 ◽  
Author(s):  
Yanxin Zhang ◽  
David G. Lloyd ◽  
Amity C. Campbell ◽  
Jacqueline A. Alderson
Keyword(s):  
Soft Tissue ◽  
Optimization Model ◽  
External Rotation ◽  
Human Subjects ◽  
Three Dimensional ◽  
Optimization Method ◽  
Upper Arm ◽  
Movement Artifact ◽  
Sinusoidal Pattern ◽  
Soft Tissue Artifact

The purpose of this study was to quantify the effect of soft tissue artifact during three-dimensional motion capture and assess the effectiveness of an optimization method to reduce this effect. Four subjects were captured performing upper-arm internal-external rotation with retro-reflective marker sets attached to their upper extremities. A mechanical arm, with the same marker set attached, replicated the tasks human subjects performed. Artificial sinusoidal noise was then added to the recorded mechanical arm data to simulate soft tissue artifact. All data were processed by an optimization model. The result from both human and mechanical arm kinematic data demonstrates that soft tissue artifact can be reduced by an optimization model, although this error cannot be successfully eliminated. The soft tissue artifact from human subjects and the simulated soft tissue artifact from artificial sinusoidal noise were demonstrated to be considerably different. It was therefore concluded that the kinematic noise caused by skin movement artifact during upper-arm internal-external rotation does not follow a sinusoidal pattern and cannot be effectively eliminated by an optimization model.

Using MR Imaging and X-Ray Fluoroscopy to Quantify the Effects of Soft-Tissue Artifact on Measurement of Knee-Joint Kinematics

2009 ◽  
Author(s):  
Massoud Akbarshahi ◽  
Justin W. Fernandez ◽  
Anthony Schache ◽  
Richard Baker ◽  
Marcus G. Pandy
Keyword(s):  
Soft Tissue ◽  
Knee Joint ◽  
Soft Tissues ◽  
Surgical Techniques ◽  
Joint Kinematics ◽  
Segmental Motion ◽  
Coordinate Systems ◽  
Knee Joint Kinematics ◽  
Soft Tissue Artifact

The ability to accurately measure joint kinematics in vivo is of critical importance to researchers in the field of biomechanics [1]. Applications range from the quantitative evaluation of different surgical techniques, treatment methods and/or implant designs, to the development of computer-based models capable of simulating normal and pathological musculoskeletal conditions [1,2]. Currently, non-invasive marker-based three dimensional (3D) motion analysis is the most commonly used method for quantitative assessment of normal and pathological locomotion. The accuracy of this technique is influenced by movement of the soft tissues relative to the underlying bones, which causes inaccuracies in the determination of segmental anatomical coordinate systems and tracking of segmental motion. The purpose of this study was to quantify the errors in the measurement of knee-joint kinematics due solely to soft-tissue artifact (STA) in healthy subjects. To facilitate valid inter-subject comparisons of the kinematic data, relevant anatomical coordinate systems were defined using 3D bone models generated from magnetic resonance imaging (MRI).

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