Improvements to magnetic tracking system for virtual reality

2006 ◽  
Author(s):  
Yue Liu ◽  
Xiaoming Hu ◽  
Yongtian Wang ◽  
Dayuan Yan
Keyword(s):  
Virtual Reality ◽  
Tracking System ◽  
Magnetic Tracking

scholarly journals Feasibility of using a fully immersive virtual reality system for kinematic data collection

2019 ◽  
Author(s):  
Kate A. Spitzley ◽  
Andrew R. Karduna
Keyword(s):  
Virtual Reality ◽  
Data Collection ◽  
Tracking System ◽  
High Volume ◽  
Virtual Reality System ◽  
Kinematic Data ◽  
Magnetic Tracking ◽  
Signal Drift ◽  
Research Grade ◽  
Rigid Segment

AbstractCommercially-available Virtual Reality (VR) systems have the potential to be effective tools for simultaneous visual manipulation and kinematic data collection. Previously, these systems have been integrated with research-grade motion capture systems to provide both functionalities; however, they are yet to be used as stand-alone systems for kinematic data collection. This study aimed to validate the HTC VIVE VR system for kinematic data collection by evaluating the accuracy of its position and orientation signals. The VIVE controller and tracker were each compared to a Polhemus Liberty magnetic tracking system sensor for angular and translational measurement error and signal drift. A sensor from each system was mounted to opposite ends of a rigid segment which was driven through fifty rotations and fifty translations. Mean angular errors for both the VIVE tracker and controller were below 0.4°. Mean translational error for both sensors was below 3 mm. Drift in the Liberty signal components was consistently lower than drift in VIVE components. However, all mean rotational drift measures were below 0.1° and all mean translational measures were below 0.35 mm. These data indicate that the HTC VIVE system may be a valid and reliable means of kinematic data collection. However, further investigation is necessary to determine the VIVE’s suitability for capturing extremely minute or high-volume movements.

scholarly journals Towards Tracking of Deep Brain Stimulation Electrodes Using an Integrated Magnetometer

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2670
Author(s):  
Thomas Quirin ◽  
Corentin Féry ◽  
Dorian Vogel ◽  
Céline Vergne ◽  
Mathieu Sarracanie ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Mean Absolute Error ◽  
Tracking System ◽  
Three Dimensional ◽  
Absolute Error ◽  
Magnetic Tracking ◽  
Magnetic Camera ◽  
Magnetic Resonance Imaging Mri ◽  
Deep Brain

This paper presents a tracking system using magnetometers, possibly integrable in a deep brain stimulation (DBS) electrode. DBS is a treatment for movement disorders where the position of the implant is of prime importance. Positioning challenges during the surgery could be addressed thanks to a magnetic tracking. The system proposed in this paper, complementary to existing procedures, has been designed to bridge preoperative clinical imaging with DBS surgery, allowing the surgeon to increase his/her control on the implantation trajectory. Here the magnetic source required for tracking consists of three coils, and is experimentally mapped. This mapping has been performed with an in-house three-dimensional magnetic camera. The system demonstrates how magnetometers integrated directly at the tip of a DBS electrode, might improve treatment by monitoring the position during and after the surgery. The three-dimensional operation without line of sight has been demonstrated using a reference obtained with magnetic resonance imaging (MRI) of a simplified brain model. We observed experimentally a mean absolute error of 1.35 mm and an Euclidean error of 3.07 mm. Several areas of improvement to target errors below 1 mm are also discussed.

A Smart Eye Tracking System for Virtual Reality

2019 ◽  
Author(s):  
Bin Li ◽  
Yun Zhang ◽  
Xiujuan Zheng ◽  
Xiaoping Huang ◽  
Sheng Zhang ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Eye Tracking ◽  
Tracking System

scholarly journals Magnetic Tracking: A Novel Method of Assessing Anterior Cruciate Ligament Deficiency

2006 ◽  
Vol 88 (1) ◽  
pp. 16-17 ◽  
Author(s):  
RK Kundra ◽  
JD Moorehead ◽  
N Barton-Hanson ◽  
SC Montgomery
Keyword(s):  
Anterior Cruciate Ligament ◽  
Tracking System ◽  
Cruciate Ligament ◽  
Magnetic Tracking ◽  
Lachman Test ◽  
Acl Deficiency ◽  
Anterior Tibial ◽  
Anterior Cruciate ◽  
Tracking Device ◽  
Acl Deficient

INTRODUCTION The Lachman test is commonly performed as part of the routine assessment of patients with suspected anterior cruciate ligament (ACL) deficiency. A major drawback is its reliance on the clinician's subjective judgement of movement. The aim of this study was to quantify Lachman movement using a magnetic tracking device thereby providing a more accurate objective measure of movement. PATIENTS AND METHODS Ten patients aged 21–51 years were assessed as having unilateral ACL deficiency with conventional clinical tests. These patients were then re-assessed using a Polhemus Fastrak™ magnetic tracking device. RESULTS The mean anterior tibial displacement was 5.6 mm (SD = 2.5) for the normal knees and 10.2 mm (SD = 4.2) for the ACL-deficient knees. This gave an 82% increase in anterior tibial displacement for the ACL deficient knees. This was shown to be highly significant with P = 0.005. CONCLUSIONS The magnetic tracking system offers an objective quantification of displacements during the Lachman test. It is convenient, non-invasive and comfortable for the patient and is, therefore, ideally suited for use as an investigative tool.

scholarly journals Development of a magnetic tracking system for monitoring soil movements induced by geohazards

2019 ◽  
Vol 92 ◽  
pp. 17007 ◽  
Author(s):  
Xiaoyu Chen ◽  
Rolando P. Orense
Keyword(s):  
Magnetic Fields ◽  
Permanent Magnets ◽  
Tracking System ◽  
Soil Liquefaction ◽  
Small Scale ◽  
Interior Point Algorithm ◽  
Tracking Accuracy ◽  
Tracking Errors ◽  
Magnetic Tracking ◽  
Soil Movements

In the study of geotechnical hazards, such as soil liquefaction and landslides, the analysis of soil movements is always one of the major preoccupations. An efficient movement sensing technique requires the tracking of subsurface soil for the purpose of examining the mechanism involved. A magnetic tracking system is therefore proposed, with permanent magnets as trackers and magnetometers as receivers. When permanent magnets, deployed within the soil to serve as excitation sources, move with soil body during a geotechnical event, they generate static magnetic fields whose flux densities are related with the positions and orientations of the magnets. Magnetometers are used as receivers to detect the generated magnetic fields, which can be further used in calculating the magnets' locations and orientations based on appropriately developed algorithms. Comparison between situations where the trackers are exposed to air and embedded within soil was conducted to evaluate the influence of soil (wet and dry) on the tracking accuracy. Also, multi-objective tracking is realized by using the particle swarm optimization (PSO) technique combined with interior-point algorithm. The tracking errors are evaluated and applications of the proposed system in small-scale laboratory tests for geohazards are discussed.

scholarly journals Virtual Reality Based Multi-Modal Teleoperation Using Mixed Autonomy

2008 ◽  
Author(s):  
Muthukkumar S. Kadavasal ◽  
Abhishek Seth ◽  
James H. Oliver
Keyword(s):  
Virtual Reality ◽  
Stereo Vision ◽  
Vision System ◽  
Tracking System ◽  
A Priori ◽  
Obstacle Detection ◽  
Remotely Operated Vehicle ◽  
Autonomous Operation ◽  
Control Interface ◽  
Video Feed

A multi modal teleoperation interface is introduced featuring an integrated virtual reality based simulation augmented by sensors and image processing capabilities on-board the remotely operated vehicle. The proposed virtual reality interface fuses an existing VR model with live video feed and prediction states, thereby creating a multi modal control interface. Virtual reality addresses the typical limitations of video-based teleoperation caused by signal lag and limited field of view thereby allowing the operator to navigate in a continuous fashion. The vehicle incorporates an on-board computer and a stereo vision system to facilitate obstacle detection. A vehicle adaptation system with a priori risk maps and real state tracking system enables temporary autonomous operation of the vehicle for local navigation around obstacles and automatic re-establishment of the vehicle’s teleoperated state. As both the vehicle and the operator share absolute autonomy in stages, the operation is referred to as mixed autonomous. Finally, the system provides real time update of the virtual environment based on anomalies encountered by the vehicle. The system effectively balances the autonomy between human and on board vehicle intelligence. The stereo vision based obstacle avoidance system is initially implemented on video based teleoperation architecture and experimental results are presented. The VR based multi modal teleoperation interface is expected to be more adaptable and intuitive when compared to other interfaces.

VR-SMART: A Virtual Reality System for Smart Home Environments

2011 ◽  
Author(s):  
Nathan D. Darnall ◽  
Vinay Mishra ◽  
Sankar Jayaram ◽  
Uma Jayaram
Keyword(s):  
Virtual Reality ◽  
Smart Home ◽  
Tracking System ◽  
Virtual Reality System ◽  
Positional Accuracy ◽  
Home Environments ◽  
Smart System ◽  
Head Mounted Display ◽  
Six Dof ◽  
Smart Home Environments

Virtual reality (VR) technologies and systems have the potential to play a key role in assisting disabled inhabitants of smart home environments with instrumental activities of daily living (IADLs). While immersive environments have useful applications in the fields of gaming, simulation, and manufacturing, their capabilities have been largely untapped in smart home environments. We have developed an integrated CAD and virtual reality system which assists a smart home resident in locating and navigating to objects in the home. Using the methods presented in this paper, a room modeled in a CAD system is imported into a virtual environment, which is linked to an audio query-response interface. The user’s head and room objects are fitted with the sensors which are part of a six DOF motion tracking system. Methods have been created to allow the inhabitant to move objects around in the room and then later issue an audio query for the location of the object. The system generates an audio response with the object’s position relative to the person’s current position and orientation. As he approaches the object, information is derived from the virtual models of both the room and the objects within the room to provide better guidance. The ability of the VR-SMART system to guide a resident to an object was tested by mounting a head mounted display (HMD) on a user located in a room. This allowed the user to navigate through the virtual world that simulated the room he occupied, thereby providing a way to test the positional accuracy of the virtual system. Results of the testing in the immersive environment showed that although the overall system shows promise at a 30% success rate, the success of the system depends on the accuracy and calibration of the tracking system. In order to improve the success of the system, we explored the precision of a second motion capture system, with more accurate results. Results confirmed that the VR-SMART system could significantly improve the assistance of disabled people in finding objects easily in the room when implemented only as an assistive system without the head-mounted display.

Wireless magnetic tracking system for radiation therapy

2009 ◽  
Author(s):  
Tae-young Choi ◽  
Wing Fai Loke ◽  
Teimour Maleki ◽  
Babak Ziaie ◽  
Lech Papiez ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Tracking System ◽  
Magnetic Tracking

scholarly journals Tracking of Brain Tumors using Vision and Neurosonography

2010 ◽  
Vol 7 (2) ◽  
pp. 123-130
Author(s):  
Rubén Machucho Cadena ◽  
Sergio de la Cruz Rodríguez ◽  
Eduardo Bayro-Corrochano
Keyword(s):  
Brain Tumors ◽  
Hough Transform ◽  
Geometric Algebra ◽  
Brain Tumours ◽  
Tracking System ◽  
Ultrasound Image ◽  
The Other ◽  
Ultrasound Probe ◽  
Geometric Transformations ◽  
Magnetic Tracking

We have developed a method to render brain tumours from endoneurosonography. We propose to track an ultrasound probe in successive endoscopic images without relying on an external optic or magnetic tracking system. The probe is tracked using two different methods: one of them based on a generalised Hough transform and the other one based on particle filters. By estimating the pose of the ultrasound probe in several contiguous images, we use conformal geometric algebra to compute the geometric transformations that yield the 3D position of the tumour, which was segmented in the ultrasound image using morphological operators. We use images from brain phantoms to evaluate the performance of the proposed methods, and our results show that they are robust.

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