scholarly journals SCALABLE OPTICAL TRACKING - A Practical Low-cost Solution for Large Virtual Environments

2011 ◽  
Keyword(s):  
Virtual Environments ◽  
Low Cost ◽  
Optical Tracking

An inertial measurement unit tracking system for body movement in comparison with optical tracking

2020 ◽  
Vol 234 (7) ◽  
pp. 728-737
Author(s):  
Rui Li ◽  
Barclay Jumet ◽  
Hongliang Ren ◽  
WenZhan Song ◽  
Zion Tsz Ho Tse
Keyword(s):  
Inertial Measurement Unit ◽  
Tracking System ◽  
Low Cost ◽  
Optical Tracking ◽  
Measurement Unit ◽  
Joint Movement ◽  
Joint Angles ◽  
Optical Tracking System ◽  
Microelectromechanical System ◽  
Inertial Measurement

The recent advancement of motion tracking technology offers better treatment tools for conditions, such as movement disorders, as the outcome of the rehabilitation could be quantitatively defined. The accurate and fast angular information output of the inertial measurement unit tracking systems enables the collection of accurate kinematic data for clinical assessment. This article presents a study of a low-cost microelectromechanical system inertial measurement unit-based tracking system in comparison with the conventional optical tracking system. The system consists of seven microelectromechanical system inertial measurement units, which could be mounted on the lower limbs of the subjects. For the feasibility test, 10 human participants were instructed to perform three different motions: walking, running, and fencing lunges when wearing specially designed sleeves. The subjects’ lower body movements were tracked using our inertial measurement unit-based system and compared with the gold standard—the NDI Polaris Vega optical tracking system. The results of the angular comparison between the inertial measurement unit and the NDI Polaris Vega optical tracking system were as follows: the average cross-correlation value was 0.85, the mean difference of joint angles was 2.00°, and the standard deviation of joint angles was ± 2.65°. The developed microelectromechanical system–based tracking system provides an alternative low-cost solution to track joint movement. Moreover, it is able to operate on an Android platform and could potentially be used to assist outdoor or home-based rehabilitation.

Accurate Infrared Tracking System for Immersive Virtual Environments

2011 ◽  
Vol 2 (2) ◽  
pp. 49-73 ◽  
Author(s):  
Filipe Gaspar ◽  
Rafael Bastos ◽  
Miguel Sales
Keyword(s):  
Virtual Environments ◽  
Large Scale ◽  
Tracking System ◽  
3D Structure ◽  
Optical Tracking ◽  
Frame Rate ◽  
Input Device ◽  
Optical Tracking System ◽  
Immersive Virtual Environments ◽  
Hardware Configuration

In large-scale immersive virtual reality (VR) environments, such as a CAVE, one of the most common problems is tracking the position of the user’s head while he or she is immersed in this environment to reflect perspective changes in the synthetic stereoscopic images. In this paper, the authors describe the theoretical foundations and engineering approach adopted in the development of an infrared-optical tracking system designed for large scale immersive Virtual Environments (VE) or Augmented Reality (AR) settings. The system is capable of tracking independent retro-reflective markers arranged in a 3D structure in real time, recovering all possible 6DOF. These artefacts can be adjusted to the user’s stereo glasses to track his or her head while immersed or used as a 3D input device for rich human-computer interaction (HCI). The hardware configuration consists of 4 shutter-synchronized cameras attached with band-pass infrared filters and illuminated by infrared array-emitters. Pilot lab results have shown a latency of 40 ms when simultaneously tracking the pose of two artefacts with 4 infrared markers, achieving a frame-rate of 24.80 fps and showing a mean accuracy of 0.93mm/0.51º and a mean precision of 0.19mm/0.04º, respectively, in overall translation/rotation, fulfilling the requirements initially defined.

Methods of Mass-Flow Characterization of Water-Glycol Mixtures Through Micro/Nano-Channels

2018 ◽  
Author(s):  
John Lee ◽  
Po-Hao Huang
Keyword(s):  
Mass Flow ◽  
Low Cost ◽  
Thermal Characteristics ◽  
Propulsion System ◽  
Optical Tracking ◽  
Gaseous State ◽  
Small Satellites ◽  
Class 1 ◽  
Nano Channel ◽  
Micro Propulsion

The design of a novel micro-propulsion system for small satellites of the nano-satellites class (1–10kg) that is low-cost, non-toxic, non-flammable, and no-pressurized at launch conditions is currently being developed at the University of Arkansas. The goal of the present micro-propulsion system is to achieve milli-Newton thrust levels with specific impulses on the order of 100s. The proposed propellant is the water-propylene glycol. However, little data is available for its fluid and thermal characteristics at the gaseous state, nor the evolution of similar mixtures through micro/nano-channels. This paper will present experimental methods of measuring the mass flow rate of the water-glycol mixtures through micro/nano-channels. A MEMS fluidic chamber fabricated with a nano-channel is used to quantify the mass flow through optical tracking of liquid interfaces confined in the chamber. The dimensions of the channels are designed with the purpose to act as a passive throttling valve that prevent liquid-phase fluids from entering into the nozzle in order to achieve a simple water-based cold-gas propulsion system.

scholarly journals Correcting Drift, Head and Body Misalignments between Virtual and Real Humans

2014 ◽  
Vol 4 (2) ◽  
pp. 1
Author(s):  
Vitor Reus ◽  
Márcio Mello ◽  
Luciana Nedel ◽  
Anderson Maciel
Keyword(s):  
Virtual Environments ◽  
Inertial Sensors ◽  
Tracking System ◽  
Low Cost ◽  
Head Tracking ◽  
Desktop Computer ◽  
Head Mounted Displays ◽  
Incremental Information ◽  
Ms Kinect ◽  
Head Rotations

Head-mounted displays (HMD) allow a personal and immersive viewing of virtual environments, and can be used with almost any desktop computer. Most HMDs have inertial sensors embedded for tracking the user head rotations. These low-cost sensors have high quality and availability. However, even if they are very sensitive and precise, inertial sensors work with incremental information, easily introducing errors in the system. The most relevant is that head tracking suffers from drifting. In this paper we present important limitations that still prevent the wide use of inertial sensors for tracking. For instance, to compensate for the drifting, users of HMD-based immersive VEs move away from their suitable pose. We also propose a software solution for two problems: prevent the occurrence of drifting in incremental sensors, and avoid the user from move its body in relation to another tracking system that uses absolute sensors (e.g. MS Kinect). We analyze and evaluate our solutions experimentally, including user tests. Results show that our comfortable pose function is effective on eliminating drifting, and that it can be inverted and applied also to prevent the user from moving their body away of the absolute sensor range. The efficiency and accuracy of this method makes it suitable for a number of applications in immersive VR.

scholarly journals Visual Behavior Modeling of Hazard Identification Assessment From Eye-Tracking Data

2020 ◽  
Author(s):  
Abner Cardoso Da Silva ◽  
Alberto Barbosa Raposo ◽  
Cesar Augusto Sierra Franco
Keyword(s):  
Virtual Environments ◽  
Low Cost ◽  
Real Life ◽  
Hazard Identification ◽  
Behavior Modeling ◽  
Visual Behavior ◽  
Gaze Behavior ◽  
Hazard Detection ◽  
Head Mounted Displays ◽  
Application Fields

The easier access to virtual reality head-mounted displays have assisted the use of this technology on research. In parallel, the integration of those devices with eye-trackers enabled new perspectives of visual attention analysis in virtual environments. Different research and application fields found in such technologies a viable way to train and assess individuals by reproducing, with low cost, situations that are not so easily recreated in real life. In this context, our proposal aims to develop a model to measure characteristics of safety professional’s gaze behavior during the hazard detection process.

scholarly journals LOW-COST DEVELOPMENT OF AN INTERACTIVE, IMMERSIVE VIRTUAL REALITY EXPERIENCE OF THE HISTORIC CITY MODEL STADE 1620

2019 ◽  
Vol XLII-2/W17 ◽  
pp. 405-411 ◽  
Author(s):  
A. Walmsley ◽  
T. P. Kersten
Keyword(s):  
Virtual Reality ◽  
Virtual Environments ◽  
Low Cost ◽  
Simple Game ◽  
Texture Mapping ◽  
Immersive Virtual Reality ◽  
City Model ◽  
Virtual City ◽  
The Individual ◽  
The Town

Abstract. As virtual reality and 3D documentation and modelling technologies become increasingly powerful and affordable tools for architecture, planning, and cultural heritage preservation and communication, it has become increasingly important to develop low-cost methodologies for the creation of 3D immersive virtual environments and interactive experiences. Doing so makes this technology more viable for institutions such as museums and other cultural institutions, who often work within strict budgets. In this paper, we describe a workflow used to build an interactive, immersive virtual reality experience around a virtual city model of the town of Stade (Germany) in the year 1620. This virtual city model is based on a physical 3D model of the town, exhibited in the Stade town hall. The workflow begins with the digitization of this model using digital photogrammetry, followed by the subsequent low- and high-polygon modelling of the individual architectural assets in Autodesk Maya, texture mapping in Substance Painter and finally visualisation within Unreal Engine 4. The results of this workflow are a detailed 3D historical environment with a high degree of realism and in which interactivity can easily be added. In addition, the workflow takes a highly iterative approach that allows the performance of the virtual environments in the game engine to be monitored at each stage of the process, and that allows adjustments to be made quickly. To increase the potential of the virtual environment as a tool for education and communication, interactive elements and simple game mechanics are currently being integrated.

scholarly journals Exploring Drugbank in Virtual Reality Chemical Space

2018 ◽  
Author(s):  
Daniel Probst ◽  
Jean-Louis Reymond
Keyword(s):  
Virtual Reality ◽  
Virtual Environments ◽  
Chemical Space ◽  
3D Visualization ◽  
Low Cost ◽  
Natural Extension ◽  
Web Based ◽  
3D Engine ◽  
Abstract Data ◽  
2D And 3D

The recent general availability of low-cost virtual reality headsets, and accompanying 3D engine support, presents an opportunity to bring the concept of chemical space into virtual environments. While virtual reality applications represent a category of widespread tools in other fields, their use in the visualization and exploration of abstract data such as chemical spaces has been experimental. In our previous work we established the concept of interactive 2D maps of chemical spaces, followed by interactive web-based 3D visualizations, culminating in the interactive web-based 3D visualization of extremely large chemical spaces. Virtual reality chemical spaces are a natural extension of these concepts. As 2D and 3D embeddings, and projections of high-dimensional chemical fingerprint spaces were shown to be valuable tools in chemical space visualization and exploration, existing pipelines of data mining and preparation can be extended to be used in virtual reality applications. Here we present an application based on the Unity engine and the virtual reality toolkit (VRTK), allowing for the interactive exploration of chemical space populated by Drugbank compounds in virtual reality. The source code of the application as well as the most recent build are available on GitHub.

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