1 Journal of Biomechanics 35 (2002) Interference during the use of an electromagnetic tracking system under OR conditions Fran-cois Poulin a, *, L.-P. Amiot a,b a ORTHOsoft Inc., 75, Queen Street, Suite 3300, Montr!eal (Qu!ebec), Canada H3C 2N6 b Department of Orthopedics, Maisonneuve-Rosemont Hospital, University of Montreal, 5415 Boulevard l Assomption, Montr!eal (Qu!ebec), Canada H1T 2M4 Accepted 8 February 2002 Abstract Many computer-assisted surgery applications use electromagnetic tracking devices and several sources of interference may reduce the accuracy of this type of system in clinical situations. This study aims to quantify interference sources in an operating room (OR) and determine if their impact on the tracking system is excessive for applications requiring millimetric accuracy. Electromagnetic noise levels were measured in a controlled environment and compared with measurements in an OR. Errors generated by this noise remained below the 0.15 mm RMS level. OR equipment was also brought in proximity to the electromagnetic receivers and the errors generated by the ensuing interference were measured. Ferromagnetic and electrical devices can produce large interference (translation errors up to 8.4 mm RMS and rotation up to 1661). However, these devices can be identified and placed at sufficient s to decrease the magnitude of their interference. In conclusion, in the absence of significant ferromagnetic or electromagnetic distortion caused by equipment often present in an OR, this electromagnetic tracking system provides valid relative measurements with millimetric accuracy to computer-assisted surgical applications. This distortion can be reduced by maximizing the s to the interfering OR equipment and integrating noise-reducing algorithms in associated software. r 2002 Elsevier Science Ltd. All rights reserved. Keywords: Electromagnetic interference; Tracking device; Operating room 1. Introduction Many medical applications require the use of a threedimensional (3D) position and orientation measuring tools. The two most common types of tracking devices used for biomechanical applications rely on optical or electromagnetic systems (Eckhouse et al., 1996). With optical systems, the main drawback is the necessity for a free line of sight from the camera to the tracker. Electromagnetic systems do not have this limitation, but several sources of interference may reduce their accuracy. Electromagnetic systems are currently in use for a variety of applications, particularly for the study of kinematics (Biryukova et al., 2000; Bottlang et al., 2000; Dykstra et al., 1993; Steffen et al., 1997), biomechanics (An et al., 1988; Bull et al., 1998; van Ruijven et al., *Corresponding author. ORTHOsoft Inc., 75 Queen Street, Suite 3300, Montr!eal, Qu!ebec, Canada H3C 2N6. Fax: address: (F. Poulin). 2000) and computer-assisted orthopedic surgery (Amiot et al., 1995, 2000; Bottlang et al., 1998). Three types of sources may interfere with the normal operation of an electromagnetic tracking system in an operating room (OR): background noise originating from ambiant electrical devices (for example: wires in the floors or ceiling, lights, MRI device in a nearby section of the hospital, etc.) (Day et al., 1998), electromagnetic fields generated by typical electrical OR equipment as well as the ferromagnetic behavior of metallic instrumentation and tools (Birkfellner et al., 1998; Milne et al., 1996). Detection of sources of magnetic interference is not simple as there are no visual cues similar to the optical system where loss of signal follows camera obstruction. It is therefore necessary to identify potential sources of interference and take steps to reduce or eliminate their effect. This study aims to quantify the interference level of these sources and determine their impact on accuracy in OR conditions /02/$ - see front matter r 2002 Elsevier Science Ltd. All rights reserved. PII: S (02)
2 734 F. Poulin, L.-P. Amiot / Journal of Biomechanics 35 (2002) Methods The tracking system used in this study (MotionStar system, Ascension Technology Corporation, Burlington, Vermont) has a published 3D RMS accuracy of 0.5 mm (Milne et al., 1996). The system is comprised of a short range emitter that produces an electromagnetic field, receivers that measure the field intensity and orientation as well as amplifier cards converting this information into 6 degrees of freedom (DOF) data. A preliminary step was done to identify some average accuracy hardware (2 receivers, 1 emitter and 2 amplifier cards). In this preliminary step, 38 receivers, 6 emitters and 13 amplifier cards were evaluated and a selection process was then based on the mean displacement error of the complete system. A test bench was constructed with two 15 cm diameter PVC tubes on which the emitter and receiver array were mounted. The emitter and receiver arrays were placed approximately 1.5 m from the ground to avoid electromagnetic interference from the displacement device or from wires and metal in Fig. 1. Receiver array displacement mechanism composed of a rotating table ( precision) mounted on an XY table (0.01 mm precision) with Mitutoyo Absolute digimatic calipers (0.01 mm precision; mm accuracy). the floor (Day et al., 1998) or ceiling. The receiver array support tube was placed on a rotating table ( precision) mounted on an XY table (0.01 mm precision). Mitutoyo Absolute digimatic calipers (0.01 mm precision; mm accuracy) were fitted to both the X- and Y-axis to allow accurate displacements (Fig. 1). This setup was installed in the middle of an electromagnetically shielded ferrite-plated anechoic room at the Centre en Recherche Industrielle du Qu!ebec (Montr-!eal, Canada), with the MotionStar amplifier cards and computer approximately 1.5 m away. Two receivers were placed 500 mm from the front of the emitter, wires pointing away, 230 mm apart and with the middle point between the receivers located 71 mm to the side of the emitter to allow use of the full range of the XY table. This receiver array was physically displaced with the XY table by increments of 71 mm in order to form a 3 3 pattern of measured positions (Fig. 2). At each of these positions, 1000 samples of the 3D position and orientation of the receiver were recorded by the computer to remove any bursts of environmental noise from nearby equipment. A randomized time interval of up to 50 ms between each sample was used in order to avoid any systematic errors due to a fixed acquisition frequency. The average standard deviation for all sets of samples was considered to be the minimum background noise. For the clinical evaluation portion of our protocol, the MotionStar system was installed in an OR at H#opital Sacr!e-Coeur de Montr!eal. The emitter and receivers were placed on plastic support devices approximately 380 mm above the OR table. The two receivers were 420 mm from the front of the emitter and 115 mm to each side. The MotionStar amplifier cards and computer were located approximately 1.5 m from the back of the emitter. An initial measurement of both receivers position and orientation was recorded 5 times (1000 samples each) and averaged to insure the reference measurement stability. Next, the following OR equipment was individually brought close to the side of one of the receivers: anesthesia equipment, an arthroscope, an Fig. 2. Experimental setup used to evaluate a controlled environment. The receiver array was displaced with 0.01 mm precision on the dashed pattern and 6 degree of freedom (DOF) measurements were recorded at each of the 9 positions.
3 F. Poulin, L.-P. Amiot / Journal of Biomechanics 35 (2002) oscillating saw, spreaders, a saw guide, scissors, intravenous monitoring equipment, positioning devices, an OR lamp, an OR table (in this case, the plastic supports were simply removed and the receivers placed directly on the table) and an instrument table. Any change in relative position and orientation between the receivers was considered to be interference caused by the specific OR equipment. The standard deviation of the 1000 samples taken with the interference was considered as noise induced by the specific OR equipment. 3. Results Although the background noise levels obtained in the OR (position: , , mm. Orientation: , , ) were slightly higher than in the shielded room (position: , , mm. orientation: , , ), the errors generated by this noise remain below the 0.15 mm RMS level and therefore do not prevent sub-millimeter accuracy. Thus, this should not excessively reduce the MotionStar s accuracy, particularly if averaging algorithms are included in the software. Increasing the from the receiver always reduced interference to levels near the background noise (Table 1). For example, noise generated by an arthroscope (light source and signal processor) at 30 cm (31.8 mm) was reduced to 0.2 mm by moving it to 120 cm. Although most metallic objects brought close to the receiver array produced some interference, only the electric and pneumatic devices produced large noise levels in the measurement, particularly with respect to the measured orientations. Orientation errors and noise levels of up to 1661 were obtained when additional directional components (C-axis) were induced by the OR equipment EM fields. All these results concern interference generated to the side of a receiver. Any differences due to interference sources approached frontally or vertically should be evaluated in further studies. 4. Discussion The use of electromagnetic tracking devices inside an OR could be considered problematic because of the potential interference from this specific environment (Milne et al., 1996; Birkfellner et al., 1998). The objective of this study was to quantify this effect with standard OR equipment. However, because of potential functional differences between makes and models, more measurements should be done to evaluate whether all OR equipment currently in use produces electromagnetic fields similar to those detected in this study. The noise measured in the shielded room is probably caused by the internal electronic components of the device (Day et al., 1998). The slightly higher background noise levels in an OR can be attributed to the surrounding OR equipment. For some clinical uses however, noise levels could probably exceed the values presented here since the acquisition frequency of the MotionStar system would not support 1000 samples in real-time. The impact of the number of averaged samples on the noise levels should be further investigated. Noise levels can also be affected by sources of electromagnetic fields like electrical equipment located close to the MotionStar magnetic field. Also, electrical equipment will have more effect on receiver measurements when the receivers are further from the emitter because the relative importance of the interfering field will be greater. These types of errors should be reduced or even completely eliminated by placing potentially noisy equipment as far from the operating field as. Considering that magnetic field intensity is inversely proportional to the cube of the, a minimal should insure that the interference from this equipment is significantly lower than the ambient background noise. Electrical equipment will also produce distortions of the MotionStar s EM field as shown by the position and orientation errors in Table 1. Ferromagnetic materials produce only this effect on the receivers but do not increase the noise levels. The intensity of the distortion is mostly a function of the of the object from the receiver, the quantity of ferromagnetic material present and its conductivity (Birkfellner et al., 1998). As a guideline to avoid any interference from the equipment in an OR, no object composed of ferromagnetic metal like mild steel should be introduced in the MotionStar field during use (Milne et al., 1996). If these items must be used within the field, special care should be taken to evaluate the validity of the measurements. Potential solutions for OR applications could include field-monitoring devices to detect any interference as well as increasing the electromagnetic output of the emitter to reduce the relative magnitude of surrounding electromagnetic fields. In this case, however, further studies should be conducted to verify that ferromagnetic interference does not also increase, and to insure that no adverse effect occurs due to increased patient exposure to electromagnetic radiation. In all cases however, maximizing the s to interfering OR equipment and integrating noise-reducing algorithms in associated software should enable the MotionStar system to provide valid and sub-millimeter precision data to OR computer applications.
4 736 F. Poulin, L.-P. Amiot / Journal of Biomechanics 35 (2002) Table 1 OR equipment interference on the receiver array Equipment Distance of equipment from receiver Interferenceinduced translation Interferenceinduced rotation Noise (mm) (deg) X (mm) Y (mm) Z (mm) C (deg) y (deg) F (deg) Anesthesist equipment As close as Arthroscope 30 cm cm cm cm Oscillating Active, as close as saw Idle, as close as Idle, 7.5 cm Idle, 15 cm Idle, 30 cm Spreaders Saw guide Intra-venous monitoring equipment Positioning devices Scissors Lamp As close as cm cm cm As close as cm cm cm cm cm As close as cm cm cm As close as cm cm cm As close as Approximately OR height Instrument As close as table 7.5 cm cm cm OR table 7.5 cm The error measurements represent the virtual receiver displacement (3D RMS translation and rotation) perceived by the system as a result of the presence ( from the side of the receivers noted in the second column) of OR equipment. The noise measurements (presented for each DOF) combine the standard background noise with the equipment interference. Increased from the receiver always reduces interference to levels near the background noise.
5 F. Poulin, L.-P. Amiot / Journal of Biomechanics 35 (2002) Acknowledgements This study was funded by ORTHOsoft Inc. for development purposes. The authors would like to thank Eric Beaumont and the staff at the surgery department of the H#opital Sacr!e-Coeur de Montr!eal for providing the medical equipment and access to an OR. References Amiot, L.-P., Labelle, H., DeGuise, J.A., Sati, M., Brodeur, P., Rivard, C.-H., Computer-assisted pedicle screw fixation. Spine 20 (10), Amiot, L.-P., Lang, K., Putzier, M., Zippel, H., Labelle, H., Comparative results between conventional and computer-assisted pedicle screw installation in the thoracic, lumbar and sacral spine. Spine 25 (5), An, K.-N., Jacobsen, M.C., Berglund, L.J., Chao, E.Y.S., Application of a magnetic tracking device to kinesiologic studies. Journal of Biomechanics 21 (7), Birkfellner, W., Watzinger, F., Wanschitz, F., Enislidis, G., Kollmann, C., Rafolt, D., Nowotny, R., Ewers, R., Bergmann, H., Systematic distortions in magnetic position digitizers. Medical Physics 25 (11), Biryukova, E.V., Roby-Brami, A., Frolov, A.A., Mokhtari, M., Kinematics of human arm reconstructed from spatial tracking system recordings. Journal of Biomechanics 33 (8), Bottlang, M., Marsh, J.L., Brown, T.D., Factors influencing accuracy of screw displacement axis detection with a D.C.-based electromagnetic tracking system. Joural of Biomechanical Engineering 120 (3), Bottlang, M., Madey, S.M., Steyers, C.M., Marsh, J.L., Brown, T.D., Assessment of elbow joint kinematics in passive motion by electromagnetic motion tracking. Journal of Orthopedic Research 18 (2), Bull, A.M.J., Berkshire, F.H., Amis, A.A., Accuracy of an electromagnetic measurement device and application to the measurement and description of knee joint motion. Proceedings of the Institution of Mechanical Engineers [H] 212 (5), Day, J.S., Dumas, G.A., Murdoch, D.J., Evaluation of a longrange transmitter for use with a magnetic tracking device in motion analysis. Journal of Biomechanics 31 (10), Dykstra, D., Ellingham, C., Belfie, A., Baxter, T., Myoung, L., Voelker, A., Quantitative measurement of cervical range of motion in patients with torticollis treated with botulinum A toxin. Movement Disorders 8 (1), Eckhouse, R.H., Penny, M.A., Maulucci, R.A., A comparison of kinematic recording instruments. Journal of Medical Systems 20 (6), : Milne, A.D., Chess, D.G., Johnson, J.A., King, G.J.W., Accuracy of an electromagnetic tracking device: a study of the optimal operating range and metal interference. Journal of Biomechanics 29 (6), Steffen, T., Rubin, K.R., Baramki, H.G., Antoniou, J., Marchesi, D., Aebi, M., A new technique for measuring lumbar segmental motion in vivo method, accuracy, and preliminary results. Spine 22 (2), van Ruijven, L.J., Beek, M., Donker, E., van Eijden, T.M.G.J, The accuracy of joint surface models constructed from data obtained with an electromagnetic tracking device. Journal of Biomechanics 33 (8),
Journal of Biomechanics 32 (1999) 629}633 Technical Note Calibration of the &&Flock of Birds'' electromagnetic tracking device and its application in shoulder motion studies C.G.M. Meskers, *, H. Fraterman,
Computer-Assisted Spine Surgery Computer-assisted spine surgery enables surgeons to view the position of their instruments against three-dimensional images of a patient s spine, increasing the accuracy
Tracking devices Virtual Reality Technology and Programming TNM053: Lecture 4: Tracking and I/O devices Referred to head-tracking many times Needed to get good stereo effect with parallax Essential for
Tracking Systems Kevin Cleary, PhD Technical Director, Bioengineering Initiative Children's National Medical Center Adjunct Professor, Department of Radiology Medical Center Washington, DC, USA email@example.com
www.led-professional.com ISSN 1993-890X Trends & Technologies for Future Lighting Solutions ReviewJan/Feb 2015 Issue LpR 47 International Year of Light 2015 Tech-Talks BREGENZ: Mehmet Arik Well-Being in
Improved Three-dimensional Image Processing Technology for Remote Handling Auxiliary System Chiaki Tomizuka Keisuke Jinza Hiroshi Takahashi 1. Introduction Remote handling devices are used in the radioactive
POLARIS OPTICAL TRACKING SYSTEMS FROM A WORLD LEADER IN NAVIGATION TECHNOLOGY The Polaris Spectra and Polaris Vicra optical tracking systems from NDI are based on over 30 years of advanced 3D measurement
Accurate Air Flow Measurement in Electronics Cooling Joachim Preiss, Raouf Ismail Cambridge AccuSense, Inc. E-mail: firstname.lastname@example.org Air is the most commonly used medium to remove heat from electronics
Application Note for SFM3000 Inlet conditions Summary Most flow sensors use a significant pressure drop to stabilize the flow that goes through the sensor. Since the SFM3000 is designed for a low pressure
Biomechanics of the Lumbar Spine Biomechanics of the Spine 6 degrees of freedom Extension & Flexion Translation Rotation Compression & Distraction The disc/annulus/all/pll complex is the major restraint
Polarization of Light Introduction Light, viewed classically, is a transverse electromagnetic wave. Namely, the underlying oscillation (in this case oscillating electric and magnetic fields) is along directions
Robot Perception Continued 1 Visual Perception Visual Odometry Reconstruction Recognition CS 685 11 Range Sensing strategies Active range sensors Ultrasound Laser range sensor Slides adopted from Siegwart
w Technical Product Information Subminiature Load Cell 1. Introduction... 2 2. Preparing for use... 2 2.1 Unpacking... 2 2.2 Using the instrument for the first time... 2 2.3 Grounding and potential connection...
1 919 1919P01 1919P03 QBM65/C, QBM75-1U/C Differential Pressure Sensors for air and non-corrosive gases, with calibration certificate QBM751-1/C QBM65/C QBM75/C Highly accurate measurements with calibration
System for inductive sensors study Constantin CERCEL, Florin GROFU Automation, Energy and Environment Department Constantin Brancusi University of Targu Jiu Calea Eroilor street, no. 30, Targu Jiu, Romania
Lab-exercises Actuators and EMC/Sensory Analysis Faculty of Mechatronics and Electrical Engineering Laboratory of Electrical Drives and Installations Lab-exercise EA - 4 Inductive Position Sensor Data:
A2.4 LIEAR POSITIO SESIG USIG MAGETORESISTIVE SESORS By Bratland, Tamara Product Line Manager, Magnetic Sensors Honeywell Solid State Electronics Center 12001 State Highway 55 Plymouth, Minnesota, 55441
Autonomous Mobile Robot-I Sabastian, S.E and Ang, M. H. Jr. Department of Mechanical Engineering National University of Singapore 21 Lower Kent Ridge Road, Singapore 119077 ABSTRACT This report illustrates
Sensors and Cellphones What is a sensor? A converter that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument What are some sensors we use every
Procedure No: SOP-018 Revision No: 0 (new document) Page No.: 1 of 8 1. INTRODUCTION AND SCOPE To obtain timely data for the purpose of air quality assessment, meteorological and climate trend reporting
CMA / Flodyne Drive for Technology Linear Position Measurement Technologies Scott Rosenberger Market Manager, Linear Position Sensing Balluff, Inc. What Are We Talking About Today? General Applications
CHAPTER 8 OBJECT REGISTERING SENSORS 8.1. Contact sensors for object registering Mechanical switches can be used as contact sensors for object registering. They generate signals of the on/off type as a
APPLYING VIRTUAL SOUND BARRIER AT A ROOM OPENING FOR TRANSFORMER NOISE CONTROL Jiancheng Tao, Suping Wang and Xiaojun Qiu Key laboratory of Modern Acoustics and Institute of Acoustics, Nanjing University,
Capacitive Proximity Sensors Capacitive proximity sensors High level of temperature stability Enhanced sensing ranges for functional reserve High level of immunity against: - Electrostatic discharge, e.g.
MRI: Magnetic resonance imaging: Like CT, MRI produces detailed cross sectional images of body regions. However the physical principles of image acquisition are different and very complicated. The following
ACTA PHYSICA DEBRECINA XLVI, 143 (2012) DINAMIC AND STATIC CENTRE OF PRESSURE MEASUREMENT ON THE FORCEPLATE F. R. Soha, I. A. Szabó, M. Budai University of Debrecen, Department of Solid State Physics Abstract
Research-Grade Research-Grade Motion Motion Capture Capture The System of Choice For Resear systems have earned the reputation as the gold standard for motion capture among research scientists. With unparalleled
Physics 41, Winter 1998 Lab 1 - The Current Balance Theory Consider a point at a perpendicular distance d from a long straight wire carrying a current I as shown in figure 1. If the wire is very long compared
Digital flow ELEMENT transmitter for continuous flow measurement Type 8036 can be combined with... DN06 to DN65 fluidic process connection Programmable outputs : one or two transistor output(s) and single
5-Axis Test-Piece Influence of Machining Position Michael Gebhardt, Wolfgang Knapp, Konrad Wegener Institute of Machine Tools and Manufacturing (IWF), Swiss Federal Institute of Technology (ETH), Zurich,
Force/position control of a robotic system for transcranial magnetic stimulation W.N. Wan Zakaria School of Mechanical and System Engineering Newcastle University Abstract To develop a force control scheme
11th European Conference on Non-Destructive Testing (ECNDT 2014), October 6-10, 2014, Prague, Czech Republic A new coating thickness measuring instrument based on eddy More Info at Open Access Database
PATIENT CARE IN RADIOLOGY Introduction to Medical Imaging CLINICAL Kalpana M. Kanal, PhD, DABR Assistant Professor, Diagnostic Physics Dept. of Radiology UW Medicine a copy of this lecture may be found
MAGNET S FALL THROUGH REELS Lesson Plan Prof.Rossana Leandro Students from the 11th grade E.E José Chaluppe Bianca de Souza Jhéssica Carvalho Yasmyn Shantala Supervision: Prof. Marisa Almeida Cavalcante(PUC/SP)
HIGH-PERFORMANCE INSPECTION VEHICLE FOR RAILWAYS AND TUNNEL LININGS. HIGH-PERFORMANCE INSPECTION VEHICLE FOR RAILWAY AND ROAD TUNNEL LININGS. The vehicle developed by Euroconsult and Pavemetrics and described
Guide for Performing a Wireless Site Survey 2.4 GHz IEEE 802.11g/802.11b/802.15.4 1 Table of Contents Table of Contents 2 Introduction 3 Wireless Characteristics 3 AMX Site Survey Tools 5 Creating a Channel
Compact, rugged housing Many mounting possibilities Status displayed via LED Immune to electromagnetic interference 1024 pulses per revolution (default) 360, 512, 1000, 1024, 2048, 2500, 3600, 4096, parametr.
Human Computer Interaction INTERACT 99 Angela Sasse and Chris Johnson (Editors) Published by IOS Press, c IFIP TC.13, 1999 1 Effects of Orientation Disparity Between Haptic and Graphic Displays of Objects
Standex-Meder Electronics Custom Engineered Solutions for Tomorrow 3-Dimensional Magnetic Mapping for Reed Sensor Accuracy Product Training Copyright 2013 Standex-Meder Electronics. All rights reserved.
Product Introduction MyoMuscle Telemyo DTS-System Telemetry system for EMG and Biomechanical Sensors DTS Device Family 3 major device categories can be used for the Direct Transmission System technology
RICHARD T ELL ASSOCIATES,INC. An Evaluation of Test Measurement Data Obtained on the KW-Gard RF Protective Suit March 30, 1998 Prepared for Euclid Garment Manufacturing Company 333 Martinel Drive Kent,
AMT 102 & 103 capacitive encoder 1 Contents Purpose the purpose of this training module is to familiarize you with rotary encoders and to show the benefits of the AMT102 & 103 Objectives understand what
ENVIRONMENT, SAFETY & HEALTH DIVISION Chapter 50: Non-ionizing Radiation Selected Radio Frequency Exposure Limits Product ID: 94 Revision ID: 1736 Date published: 30 June 2015 Date effective: 30 June 2015
User s Manual Inductive Analog Position Sensor BIL SmartSens No. 836 508 E Edition 0802 Compact design Analog output voltage/current Non-contact High repeat accuracy High temperature stability High linearity
Physics Lab Report Guidelines Summary The following is an outline of the requirements for a physics lab report. A. Experimental Description 1. Provide a statement of the physical theory or principle observed
l MTS Systems Corporation Sensors Division 3001 Sheldon Drive Cary, NC 27513 Phone 919-677-0100, Fax 919-677-0200 TECHNICAL PAPER Part Number: 08-02 M1166 Revision A Magnetostrictive Level Sensors David
Implant Failure of Posterior Lower Spinal Instrumentation (A clinical & surgical Challenge) B Y Mohamed Mohi El-Din, MD The Department of Neurosurgery, Faculty of Medicine, Cairo University The purpose
SPECIFICATIONS High resolution High accuracy Contactless magnetic encoder for linear measurement In harsh environments Works with magnetic scale with 1mm pole pitch Small housing FEATURES Resolution: 5
HB 11-26-07 Magnetic Field of a Circular Coil Lab 12 1 Magnetic Field of a Circular Coil Lab 12 Equipment- coil apparatus, BK Precision 2120B oscilloscope, Fluke multimeter, Wavetek FG3C function generator,
Team Workshop Problem 17 The Jumping Ring Prof. E.M. Freeman and Prof. D.A. Lowther EMF is at the EED/CST London, UK, e-mail 10016.3130@Compuserve.com from Internet. DAL is at the EED/McGiII, Canada, e-mail
Understanding Capacitive Position Sensors 2011 MicroSense, LLC Table of Contents 1. Introduction to Capacitive Sensors... 3 1.1 Characteristics of Capacitive Sensors... 3 1.1.1 Non Contact... 3 1.1.2 High
Automated Pose Determination for Unrestrained, Non-anesthetized Small Animal Micro-SPECT and Micro-CT Imaging Shaun S. Gleason, Ph.D. 1, James Goddard, Ph.D. 1, Michael Paulus, Ph.D. 1, Ryan Kerekes, B.S.
Determining the Posture, Shape and Mobility of the Spine The World of Biomechanics Assessment of the Mobility Function Using a special Triple Cervical marker set comprising miniature ultrasound transmitters,
Long-Range Human-Body-Sensing Modules with Capacitive Sensor Takeshi Togura, 1 Koji Sakiyama, 1 Yasushi Nakamura, 1 and Kazuya Akashi 1 Our company has been developing automotive capacitive sensor modules
Overview of functional principles The type, size, shape and surface characteristics of the objects to be recorded, the distance between the sensor and the object, and the environmental conditions determine
THE ALIGNMENT STRATEGY FOR THE SPIRAL2 SUPERCONDUCTING LINAC CRYOMODULES R. Beunard, GANIL, BP 55027, 14076 CAEN, CEDEX 5, France Abstract The SPIRAL2* project, located at the GANIL** facility in Caen,
AEDA-3300 Series Ultra Miniature, High Resolution Incremental Kit Encoders Data Sheet Description The AEDA-3300 series are high performance, cost effective, three-channel optical incremental encoder modules
8.4 8.4 Resonance in Air Columns Sound waves from one source can cause an identical source to vibrate in resonance. Just as with mechanical resonance (section 6.7), a small force produces a large vibration.
OPERATING PRINCIPLES FOR PHOTOELECTRIC SENSORS Photoelectric These sensors use light sensitive elements to detect objects and are made up of an emitter (light source) and a receiver. Four types of photoelectric
Posterior Referencing Surgical Technique Posterior Referencing Surgical Technique INTRO Introduction Instrumentation Successful total knee arthroplasty depends in part on re-establishment of normal lower
Liquid Level Sensor Installation on pipes. Sensing by means electrostatic capacity and is not influenced by the color of the pipe or liquid. Available in 8 to mm dia. and to mm dia. models to enable sensing
Physics 182 - Spring 2012 - Experiment #8 1 Experiment #8, Magnetic Forces Using the Current Balance 1 Purpose 1. To demonstrate and measure the magnetic forces between current carrying wires. 2. To verify
Synthetic Sensing: Proximity / Distance Sensors MediaRobotics Lab, February 2010 Proximity detection is dependent on the object of interest. One size does not fit all For non-contact distance measurement,
Obtaining the speed of light using the Foucault Method and the PASCO apparatus. Quintin T. Nethercott and M. Evelynn Walton University of Utah Department of Physics and Astronomy Advanced Undergraduate
Patient Alignment Estimation in Six Degrees of Freedom using a CT-scan and a Single X-ray Image B. P. Selby 1, G. Sakas 1, S. Walter 2, W.-D. Groch 3, U. Stilla 4 1 Cognitive Computing and Medical Imaging,
Chapter 13: Spinal Navigation Ben J Garrido, MD, Rick C Sasso, MD I. Key Points -Allows intraoperative real time navigation of instruments relative to the spinal anatomy -Provides 3-D real time anatomical
TM Tech Notes Certainty 3D November 1, 2012 To: General Release From: Ted Knaak Certainty 3D, LLC Re: Structural Wall Monitoring (#1017) rev: A Introduction TopoDOT offers several tools designed specifically
http://www.diva-portal.org Postprint This is the accepted version of a paper presented at Actuator 0. Citation for the original published paper: Bissal, A. (0) Numerical modelling and experimental testing
Force 3-omponent Measuring System for utting Force Measurement During Turning Modular system for measurement of cutting forces when turning outside and inside diameters on turret lathes. Machine adapters
Long-distance Capacitive Proximity Sensor Capacitive Proximity Sensor with Adjustable Sensitivity Detects both metallic and non-metallic objects (glass, lumber, water, oil, plastic, etc.) without direct
Determining The Right Lift Truck Navigation System For Your Very Narrow Aisle (VNA) Warehouse Determining The Right Lift Truck Navigation System For Your Very Narrow Aisle (VNA) Warehouse Today s pressures
REAL TIME 3D FUSION OF IMAGERY AND MOBILE LIDAR Paul Mrstik, Vice President Technology Kresimir Kusevic, R&D Engineer Terrapoint Inc. 140-1 Antares Dr. Ottawa, Ontario K2E 8C4 Canada email@example.com
Physics 202 Problems - Week 8 Worked Problems Chapter 25: 7, 23, 36, 62, 72 Problem 25.7) A light beam traveling in the negative z direction has a magnetic field B = (2.32 10 9 T )ˆx + ( 4.02 10 9 T )ŷ
Using angular speed measurement with Hall effect sensors to observe grinding operation with flexible robot. François Girardin 1, Farzad Rafieian 1, Zhaoheng Liu 1, Marc Thomas 1 and Bruce Hazel 2 1 Laboratoire
InnoWeek on RES July 03,2013, Patras, Greece THE STRUCTURAL HEALTH MONITORING SYSTEM OF THE RION ANTIRION BRIDGE CHARILAOS TRIKOUPIS Akis Panagis Monitoring engineer Gefyra S.A. INDEX 1. Introduction-Structure
Description Lab 5: Projectile Motion In this lab, you will examine the motion of a projectile as it free falls through the air. This will involve looking at motion under constant velocity, as well as motion
A MATTER OF NATIONAL SECURITY Applications for Fiber Optic Microphones SOM3/SOM4/SOM5 Key Applications + Security + Industrial + Oil & Gas + Power Utilities + Medical/MRI www.winkelmann.co.uk Our aim is
Your consent to our cookies if you continue to use this website.