Ultrasonic calibration of a magnetic tracker in a virtual reality space

Abstract-This paper aims to present all the study done on the SPIDAR, which is a tracking and haptic device, in order to improve its accuracy on the given position. Firstly we proposed a new semi-automatic initialization technique for this device using an optical tracking system. Then, we propose to use Support Vector Regression (SVR) to calibrate the SPIDAR in order to reduce location errors. We obtained very good results with this calibration, since we reduced the mean error by more than 50%.

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“…The easiest method is the linear interpolation [4] but it doesn't correct non-linear systems, so it's very limited.…”

Section: Related Workmentioning

confidence: 99%

SPIDAR calibration using Support Vector Regression

Boudoin

Maaref

Otmane

et al. 2010

2010 2nd International Conference on Image Processing Theory, Tools and Applications

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“…The main disadvantage in using this technology is that most of the CAVEs are built on iron frames and metallic masses may alter the magnetic field measured by the sensors. Research at the Illinois University (M. Ghazisaedy et al, 1995) offers a good illustration of the magnetic field distortions. They also present a method to calibrate the system to improve the accuracy, by correlating the measurements with ultrasonic sensors.…”

Section: Related Workmentioning

confidence: 99%

PRACTICAL DESIGN AND IMPLEMENTATION OF A CAVE SYSTEM - High Quality Four Walls CAVE Howto

Peternier

Cardin

Vexo

et al. 2007

Proceedings of the Second International Conference on Computer Graphics Theory and Applications

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Abstract:CAVE systems are nowadays one of the best Virtual Reality (VR) immersive devices available for rendering virtual environments. Unfortunately, such kind of hardware is extremely expensive, complex and cumbersome, thus limited in its spread. Several cheaper solutions already exist, but they implement usually only a subset of features of a professional CAVE. In this paper we describe how we have built a low cost CAVE with four screens (three walls and a floor), stereographic rendering and user tracking by only using hardware commonly available on the market and free software, we show the different solutions and work-around we implemented to solve the problems we encountered and we conclude with an evaluation of our system by using two applications we developed with it.

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“…Among most frequently used long-range systems of this type are Flock of Birds (Ascension Technology Corporation) and 3Space Fastrak (Polhemus, Inc.). Both devices are based on a design that uses orthogonal electromagnetic fields to sense 3D position and orientation [1][2][3][4]: the electromagnetic transmitter contains three orthogonal coils that are pulsed in a sequence, the receiver also has three orthogonal coils that measure the electromagnetic field produced by the transmitter, the strength of the received signals is compared to the strength of the sent pulses to determine the position and compared to each other to determine the orientation. The measurements are rather noisy, therefore an additional filtering is required.…”

Section: Introductionmentioning

confidence: 99%

“…An experimental investigation was undertaken [2] to study the effects of external fields present in a typical working environment and the presence of metals near the transmitter or receiver. Static errors as high as 4 feet have been observed near the maximum range of the tracking system [3]. The manufacturers of the tracking systems suggest that there should be no metal components near the transmitter and receiver, which is often not possible to achieve due to the construction limitations of the VR systems.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, it has been shown [3][4][5] that the quality of VR experience and user perception and performance is quite dependent on the accuracy of the tracking system. K. Meyer et al [4] discussed the effects of inaccurate position tracking on the illusion of presence in a virtual environment and pointed out a number of problems that may result from it including motion sickness, absence of perceptual adaptation, intersensory conflicts, etc.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Calibration of electromagnetic tracking devices

Kindratenko

1999

Virtual Reality

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Electromagnetic tracking devices are often used to track location and orientation of a user in a virtual reality environment. Their precision, however, is not always high enough due to the dependence of the system on the local electromagnetic field that can be easily altered by many external factors. The purpose of this article is to give an overview of the calibration techniques used to improve the precision of the electromagnetic tracking devices and to present a new method that compensates both the position and orientation errors. It is shown numerically that significant improvements in the precision of the detected position and orientation can be achieved with a small number of calibration measurements to be taken. Unresolved problems and research topics related to the proposed method are discussed.

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Ultrasonic calibration of a magnetic tracker in a virtual reality space

Cited by 48 publications

References 1 publication

SPIDAR calibration using Support Vector Regression

SPIDAR calibration using Support Vector Regression

PRACTICAL DESIGN AND IMPLEMENTATION OF A CAVE SYSTEM - High Quality Four Walls CAVE Howto

Calibration of electromagnetic tracking devices

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