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1THE VICON MANUAL>

NAVIGA TION PUBLICA TION

THE VICON MANUAL

2THE VICON MANUAL< >


The V icon ManualCopyright © 2002 -2005 OMG Plc.All rights r eser vedManual pr epared by Peter T ebbutt, John W ood and Michael King.

This manual describes the following softwar e and har dware:• Vicon W orkstation softwar e (version 4.2 or higher)• Vicon Datastation:

• 460• 612• 624• V6• V8i

Intended AudienceThis manual is intended for operators of Vicon systems who ar e familiar withWindows operating system softwar e.

TrademarksThe following ar e register ed trademarks or trademarks with r egistrationpending:

Company Infor mationVicon Motion Systems Ltd. Vicon Motion Systems Inc.14 Minns Business Park 9 Spectr um PointeWest W ay Lake For estOxfor d OX2 0JB Califor niaUK USATel: +44 1865 261800 Tel: 949 472 9140Fax: +44 1865 240527 Fax: 949 472 9136

http://www .vicon.com

Micr osoft Corporation

Acclaim T echnologies inc.

Alias|Wavefront

Kaydara, inc.

OMG Plc

OMG Plc

Windows 95/98/NT/2000

Acclaim

Alias, Maya

FiLMBOX, Kaydara

Vicon

BodyBuilder , BodyLanguage,

DynaCal

CONTENTS



MOTION CAPTURE WITH THE VICON SYSTEM 4Intr oduction 4How Vicon W orks 4Your Vicon System 4Workflow 6This Manual 6Technical Suppor t 7Some Vicon T erminology 8

VICON HARDW ARE 10A quick tour of the har dware 10

ADDITIONAL INFORMA TIONRevision histor y

MOTION CAPTURE WITH THE VICON SYSTEM

IntroductionMotion captur e is the r ecor ding of movement by an ar ray of video cameras inorder to r eproduce it in a digital envir onment. This thr ee-dimensionalreproduction has many uses:

• Medical assessment of movement disor ders

• Understanding of athletic techniques

• Generating lifelike character animation for movies, video games, br oadcast and webcast.

• Incorporating motion into vir tual envir onments for engineering design

The Vicon system includes har dware (cameras etc.) and softwar e applicationsfor the complete contr ol and analysis of motion captur e. This manual guides theuser thr ough the entir e process, fr om setting up and handling har dware thr oughcapturing movement to analysing and pr ocessing the data.

How V icon WorksA typical motion captur e space comprises an ar ea – the capture volume –surrounded by a number of high-r esolution cameras. Each camera has a ring ofLED str obe lights fixed ar ound the lens. The subject, whose motion is to becaptur ed, has a number of r eflective markers attached to their body , in well-defined positions. As the subject moves thr ough the captur e volume, light fr omthe str obe is r eflected back into the camera lens and strikes a light sensitiveplate cr eating a video signal. The Vicon Datastation contr ols the cameras andstr obes and also collects these signals, along with any other r ecor ded data(sound or analogue signals fr om for ce plates for gait analysis). It then passesthem to a computer on which the Vicon softwar e suite is installed.

Workstation is the central application of the Vicon softwar e suite used to collectand process the raw video data. It takes the two-dimensional data fr om eachcamera, combining it with calibration data to r econstr uct the equivalent digitalmotion in thr ee dimensions. This can be viewed in W orkstation as a vir tualthree-dimensional motion. After this r econstr uction the data may be passed toother Vicon applications for analysis and manipulation or to thir d par tyapplications such as those used for digital animation or vir tual envir onments.

Your Vicon SystemSeveral systems ar e cur rently available fr om Vicon Motion Systems Ltd. Theydif fer in their appearance, the number of cameras that may be used and thesoftwar e. Your choice of system will have been influenced by the type of workyou intend to do.




The Datastation contr ols the cameras and in tur n sends data to the W orkstationPC. In appearance it r esembles standar d desktop or upright computers. Thesystem name is clearly labelled on the fr ont of the Datastation case.

Vicon supplies a number of camera types for motion captur e. Examples ar e theMCam series and LCam used for small volume work. Note that you cannot usethir d par ty cameras with a Vicon system and you cannot mix dif ferent cameratypes in a system.

Your Vicon Softwar e Suite installation CD includes all available Viconapplications. The licenses you have pur chased ar e contr olled by the Dongleincluded and this should be plugged into the parallel por t of your contr olling PC. The following may be included with your system:

WorkstationWorkstation is the central application for motion captur e. In addition toproviding the contr ol inter face for your system it includes tools for editing andclean up of motion captur e data.

BodyBuilderBodyBuilder pr ovides advanced editing of and modelling tools. It allows you tocreate your own kinematic and/or kinetic models. Vicon supplies examplemodels for biomechanical analysis. Vicon also supplies animation models forcreating Acclaim skeletal and motion files for impor t in to many of the commonanimation packages.

PolygonPolygon is a multimedia r epor ting, analysis and pr esentation tool. It is similarto a web-authoring tool but allows the inclusion of all Vicon data e.g.,reconstr ucted thr ee-dimensional motion, interactive graphs and so on.

Plug-in GaitPlug-in Gait is a sample Vicon ‘Plug-in ’ that you r eceive when you pur chasePolygon. It is used in the modelling of all kinds of human movement includinggait, dance and spor ting activities, etc.

Plug-in ModellerPlug-in Modeller is a sample plug-in that allows you to r un BodyBuilder modelsdirectly in W orkstation. A sample model included with the Enter tainmentversion allows you to cr eate Acclaim Skeleton and Motion files fr om your motioncaptur e data. If you have cr eated models using BodyBuilder then you can usethese with Plug-in modeller , saving you time.

MobiusMobius is an ar tistic tool for the manipulation of Acclaim for matted motioncaptur e data. It includes a range of tools for skeletal adjustment and motioncomposition facilities.

Datastation



Cameras

Softwar e


WorkflowHow you use the Vicon system depends mostly on the type of work you do, andto some extent, wher e you do it.

Whatever the system you use, you will still have the same general componentsand you will set these up and use them in much the same way . Some of the waysyou work with one Vicon system, will dif fer - with dif ferences being mor eapparent as you use mor e advanced methods and expor t the data to otherapplications.

In most cases you will star t by considering the type of motion captur e youintend to per form and the space you have available. Y ou may have a per manentlaborator y or studio with fixed cameras or you may have to change locationever y day . You will:

• Set up and connect the equipment, install the softwar e

• Check all the connections ar e cor rect and that the system is working cor rectly

• Decide what movements ar e going to be captur ed

• Set up the data management system (Eclipse) in or der to keep all of your data well or ganised

• Position cameras to cover desir ed captur e volume while maintaining appropriate overlapping r egions

• Calibrate the system.

• Prepare subject by taking any necessar y subject measur ements and then attaching the desir ed marker set.

• Make use of the Autolabel featur e by calibrating the subjects

• Captur e your data.

• Process and Edit the data

• Possibly model the data

• View the data

• Save and expor t the data to other Vicon or thir d par ty applications

This ManualThe layout of the Vicon Manual r eflects this general workflow . It is divided intoa number of sections. Each chapter in these sections is dedicated to a self-




contained task. Most chapters describe what you will do – a kind of tutorialsystem. Wher e it is impor tant to understand underlying principles somechapters will be descriptive, in pr eparation for a task that follows.

Towar ds the end of the manual we include a r eference section. This givesimpor tant infor mation about the system and a pr oblem solving section. Thesections ar e described in mor e detail below .

Ever ything to do with getting your Vicon System up and r unning: includes adescription of the various par ts, making the connections, what the softwar edoes and checking the system is working.

A step-by-step guide to the basics of motion captur e: setting up, handling data,preparing your subject, calibrating the system and – motion captur e. Otheressential steps ar e the cleanup and pr ocessing of your data and automatingyour work.

This section describes some optional featur es of the Vicon Motion Captur esystem:

• Analogue captur e, e.g., using for ce plates or EMG

• Audio captur e

• Timecode and Genlock

• Movie Captur e

• Using Real-time

• Using Plug-ins

Some advanced techniques:

• Capturing multiple subjects

• Capturing in small volumes – with examples for facial and hand captur e

A compr ehensive r eference including keyboar d shor t cuts, flow char t guides formotion captur e scenarios, glossar y and file type definitions.

Technical Suppor tIn some cases wher e you do not find a solution using this manual ther e are twosuppor t options available:

• Visit the Vicon suppor t W eb site http://suppor t.vicon.com



Preparation

The Essentials ofMotion Captur e

System Options

Advanced Captur eTechniques

Vicon Refer ence


On registering to use the web site you will gain access to all the latest suppor tinformation and solutions.

• Call a Vicon suppor t engineer

• Email suppor [email protected]

Some V icon TerminologyAlthough this manual includes a compr ehensive glossar y it will be useful tobecome familiar with a few impor tant ter ms befor e you star t using the system.

The Datastation is the har dware component that contr ols the cameras andcaptur es the data. This is the box labelled with the name of the system you ar eusing, for example V8i or 612. W orkstation is the softwar e running on the PCthat contr ols the Datastation – for this r eason the PC is sometimes r eferred toas the W orkstation or (mor e clearly) the W orkstation PC.

The W orkstation PC is connected to the Datastation using a simple networkconnection, the Datastation to the cameras by a system of cables.

The str obe is a cir cular set of light emitting diodes that fits snugly ar ound thelens of an individual camera. Markers ar e reflective spher es attached to thebody of the subject (the person, animal or whatever else) whose movement isto be r ecor ded. Light fr om the str obe is r eflected by the markers back into thecamera. A filter ensur es that only light the colour of the str obe (r ed or infra-r ed)is allowed to strike the light sensitive plate behind the lens. As such the cameraconver ts the light into a video signal that is pr ocessed in the Datastation andthen transfer red to the W orkstation PC for r econstr uction.

Vicon ’s data management system is called Eclipse. Motion captur e producesseveral data files, raw video data, pr ocessed (thr ee-dimensional) data, moviedata and analogue data. In addition the system uses several files – to hold dataabout the system, calibration objects, camera calibrations and so on. Eclipseallows you to manage all of these files. Eclipse is accessed thr ough the DataDirector y window .

Within the data hierar chy used by Eclipse the levels ar e called Nodes. The mostimpor tant of these ar e Sessions and T rials. A T rial is the name given to the datacaptur e process and the gr oup of files in which the data is stor ed. The amountof data captur ed depends on the speed of the cameras you ar e using, the lengthof time taken for the captur e, and the kinds of data you ask the system tocaptur e.

A session is in r eality a folder on your har d drive containing a gr oup of trials andall the system files associated with them. This allows you to r ecreate ever ythingthat went on in your studio or laborator y, just as it happened on the day ofcaptur e, at any time in the futur e. The name has been chosen to r eflect whatgoes on in r eal life, a session being a single gr oup of captur ed movements –



Datastation andWorkstation

Cameras, Str obes and markers

Eclipse

Sessions and T rials


though you can cr eate as many sessions as you wish at any one time.

The Captur e Volume is the space in which the subject will move. Calibration isthe pr ocess that linearises each camera and measur es each camera ’s positionrelative to the others. The calibration data is used in the r econstr uction pr ocessto cr eate the vir tual thr ee-dimensional motion in W orkstation.

During data captur e the Datastation generates and then uploads thecoor dinates of each marker . This is stor ed in your trial but can also be viewedin real time using the Live Monitor window in W orkstation. This is a ver y usefuldiagnostic tool, allowing you to select the view fr om any camera and see thetwo-dimensional r epresentations of the markers. For example you can visualisehow much of the Captur e Volume can be viewed by each camera, optimisecamera sensitivities and str obe intensities and see whether ther e are anyextraneous sour ces of light or r eflections r eaching the selected camera.

This view should not be confused with the Real-time featur e available as anoption with selected systems. Y ou can r ead mor e about this option in theAdvanced Motion Captur e chapter .

Reconstr uction is the calculation of the thr ee-dimensional position of eachmarker in each frame. W orkstation does this using the two dimensional datafrom each camera, calibration parameters and a user defined set ofreconstr uction parameters that depend on the volume and the type of captur e.

A trajector y is the path of a marker during the trial. W orkstation calculates thetrajectories by joining the positions for each marker fr om frame to frame. Theseare displayed in a window within W orkstation called the 3D W orkspace. Y ou canview the motion as a number of unlabelled markers (white dots), cr eate simplestick figur e to r epresent the subject and view the trajectories over any specificnumber of frames. In addition the 3D W orkspace window allows you to view themotion fr om any angle and zoom in and out by clicking and dragging the mouse.

Although the eye can distinguish markers and trajectories, they ar e essentiallymeaningless for analysis until they have been identified. This identification is atwo-step pr ocess. Y ou must first manually label each marker once for eachsubject. Y ou can then cr eate an "Autolabel Calibration" that can be used tolabel the markers in your other trials automatically .

The Autolabel Calibration looks for consistent patter ns amongst markers. Y oucan cr eate your own marker sets that can utilize the Autolabel Calibrationfeature for any type of subject or captur e.

Real-time is an additional featur e that may be pur chased with your Viconsystem. This per forms reconstr uction of data in r eal time so that the motion canbe viewed in the digital envir onment dir ectly . This is excellent for instantfeedback for biomechanical r etraining and visualisation of animation scenes.Real-time needs additional har dware and softwar e components.



Live Monitors

Reconstr uction,Trajectories and 3D

Workspace

Labelling

Real-time

Captur e Volume and Calibration

VICON HARDWARE

Vicon HardwareBefore setting up it will be useful to familiarise yourself with the Vicon systemcomponents. The actual numbers and types of cer tain component will dif ferdepending on the system you have pur chased. This chapter covers the mostcommon Vicon components needed to r un your system.

The minimum Vicon system consists of the following major components:

• Vicon DA TAST ATION

• A host WORKST ATION PC

• A 100 base T TCP/IP Ether net network connection

• Camera units with inter facing cables

• System and analysis softwar e

• Dynacal calibration object

• Accessories kit

• Tripods or other camera mounting devices

There may be additional har dware and enhancements depending on the systemyou have pur chased. These may include har dware for the inter facing of VideoTape recor ders, GenLock, analogue or audio channels and a synchr onised colourvideo channel.

A quick tour of the har dwareFull details of the har dware are given in the Har dware Manual (included PDFformat on your installation CD). Her e we pr ovide a shor t description of the maincomponents.

The camera and str obe unit is the par t of the Vicon system that collects lightfrom the r eflective markers on your subjects. The str obe emits light in time withthe camera, illuminating the r etro-reflective markers attached to the subject.The markers r eflect light straight back to the camera wher e they pass thr ougha filter that allows only light of the same wavelength thr ough to be focussed onthe camera ’s sensitive plate.

The camera and str obe ar e separate units. On our M-Cam the str obe ring fitsaround the lens, being held in place by a magnetic strip. The str obe connectselectrically via a shor t flying lead. Plug the lead into the socket on the fr ontpanel.

Two types of str obe ar e available, visible and infra-red. In the case of the infra-red str obe you must exer cise some caution. Pr olonged, dir ect exposur e of the



Cameras and Str obes

VICON HARDWARE

retina of the eye to infra-r ed light can be hazar dous. Please do not look straightat the str obe for long periods of time when it is on (as indicated by a small gr eenLED at the top of the str obe.

The cameras ar e connected via Camera Cables to Camera Inter face Units,(sometimes called Br eak Out Boxes or BOBs). The Camera Inter face Unitscombine the signals fr om thr ee camera channels so they can be car ried via one14-pin tr unk cable to the Datastation. The fr ont panel of the BOB has thr ee pairsof sockets labelled CAM1, CAM2 and CAM3. In MCam type systems each pairof sockets links to one camera. The 12-pin socket car ries power and synchr o-nising signals to the cameras. The phono socket takes video signals fr om thecamera back to the Datastation. The 14-pin cables fr om the BOBs to theDatastation come in fixed pairs. In MCam 2 systems a single cable links theCamera Inter face Unit to the camera.

The Datastation contr ols cameras and analogue devices used to captur e data.It is the essential link between these and the computer used to pr ocess thedata.

The Datastation r esembles a personal computer without a monitor and islabelled with your system version number . The Enter tainment and Animationseries ar e black; the Science & Engineering series (612, 460) ar e white. Theconnectors may be on the fr ont panel or the r ear.



THE MCAM2 STYLE OF CAMERA,

FRONT AND REAR P ANEL

Camera Inter face Units

SCHEMA TIC DIAGRAM OF THE

CAMERA INTERF ACE UNIT

Datastation

VICON HARDWARE

Below ar e examples of some of our systems of the dif ferent systems. Note thatconfigurations may be dif ferent depending on your par ticular system.

Workstation is the softwar e application for contr olling the Datastation and thedata captur e process. It is also a common name used for the PC on which it isinstalled. Y ou may have pur chased this fr om Vicon Motion Systems Ltd, or youmay be using a computer of your own. The W orkstation PC should be linkedthrough a network to the Datastation. Y ou will need to have W orkstationsoftwar e installed on this computer . The softwar e license is contr olled using adongle plugged in the parallel por t of the PC.

All contr ol and analysis softwar e is included on your Vicon Installation CD.However , you will only be able to r un the applications that ar e licensed in yourDongle. The table below briefly describes the purpose and uses of eachapplication.



SCHEMA TICS OF 612 AND V81

FRONT P ANELS

TYPICAL SYSTEM HARDW ARE

SPECIFICA TIONS System

460

612

624

V6

V8i

Primary use

Science and

Engineering

Science and

Engineering

Science and

Engineering

Enter tainment /

Animation

Enter tainment /

Animation

Max. no. of cameras

6

12

24

6

24

Workstation PC

Softwar e

VICON HARDWARE

Calibration of the Vicon system is one of the most impor tant steps in capturingmotion and r ecor ding data. Calibration allows the system to define the captur evolume and the r elative positions and orientation of the cameras. Thisinformation is then used with the data fr om each camera to cr eate the thr ee-dimensional motion on your computer – a pr ocess called r econstr uction.

There are two types of calibration: static and dynamic:

Static calibration is used to set the origin and the dir ection of the axes. The L-Frame and FlatCal ar e used for static calibration, the for mer being used for full



THE VICON SOFTW ARE SUITE,

MAIN COMPONENTS Application

Workstation

BodyBuilder

Polygon

Mobius

Real-time

Primary use

Contr ol of Vicon system; calibration, data captur e, data

management, data r econ-str uction, basic data editing

Advanced data editing and modelling

Multi-media pr esentation, analysis and Repor ting tool –

allows development of pr esentations using all Vicon

data including r econstr ucted thr ee-dimensional motion.

Acclaim for matted skeletal and motion composition

such as blending separate moves into one motion and

transfor ming the motion of a per former onto a dif ferent

size or shape CG character .

Allows user to r econstr uct, label, model and view

motion data in r eal time.

Dynacal CalibrationObjects

TYPES OF CALIBRA TION OBJECT :

L-FRAME (LEFT), W AND (CENTRE)

AND FLA TCAL (RIGHT)

VICON HARDWARE


NAVIGATION PUBLICATION

body capture, the latter for small volumes. They both have an L shaped arrangement of reflective material, three on one arm and one on the other. The L-Frame is transported as separate arms and should be constructed when needed using the locating pins and thumb screw. The clinical version of the L-Frame includes alignment devices so that the frame can be aligned accurately with force plates positioned in the floor.

Dynamic calibration is used to calculate the relative positions and orientation of the cameras. The dynamic calibration object is called a wand. For medium and large volumes this is a rod with two 50mm reflective balls placed 500mm apart. For small volumes use the rod with 14mm spheres 100mm apart.

The act of dynamic calibration involves moving throughout the capture volume, waving the wand so that it passes through as much of the Capture Volume as possible allowing each camera to record the wand in several orientations.

Object Length Large Static or L-Frame 104 cm Small Static or L-Frame ~50 cm Facial 28 cm Large Wand 500 mm (large markers) Small Wand 100 mm

APPROXIMATE DIMENSIONS OF CALIBRATION OBJECTS

For static calibration objects the length given is that with the single marker.

Standard Vicon System Accessory Kit

This chapter describes the type of contents that can be included in an accessory kit supplied with a Vicon system. The number and type of contents depend upon the specific Vicon application you have ordered.

NOTE For details on the type and number of items actually supplied with your Vicon system, see the bill of materials accompanying your product shipment. If any items are missing on receipt, or if you require additional accessories later, please contact Vicon Motion Systems or your nearest agent or distributor.

Accessory Kit Contents

A Vicon system accessory kit may typically include:

• Vicon markers: The material covering the markers is retroreflective, consisting of tiny glass spheres under a protective film. The Vicon markers are sensitive to skin oil and should be handled with care. If they are allowed to become greasy and dirty, their optical efficiency will be degraded.

• Tape:

• Marker-fixing tape specially designed to adhere well to human skin without creating an allergic reaction. It can only be used once. The tape does not perform well if the skin becomes very wet with sweat. Under these circumstances, Vicon Motion Systems recommends the use of medical grade elastic strips.

VICON HARDWARE


NAVIGATION PUBLICATION

• Micropore tape

• Gaffer tape

• Vicon Lycra suit

• Velcro roll

• HASP licensing dongle

• Miscellaneous items appropriate for the Vicon application you have ordered

Vicon Motion Systems reserves the right to alter the content of the Accessory Kit for any particular application without notice.

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