System information

Vicon MX Hardware System Reference Glossary-23
Vicon application software. Also see
Kinematic model, Segment Axes, and
Subject.
Segment Axes The embedded
coordinate reference frame for a segment
in the kinematic model for a subject
whose motion is being captured or
analyzed in a Vicon system. This can be
visualized as an element of the 3D
representation of the subject. Also see
Kinematic model, Segment, and Subject.
Sensor A device that measures or
detects a physical quantity such as
pressure, motion, sound, or light and
converts it into an analog or digital
representation. Also see Analog sensor
and Camera video sensor.
SIMM export plug-in A Vicon system
option for Workstation. This plug-in
exports joint angles, kinetics,
trajectories, force plates, and analog data
to the files necessary to run a SIMM
model. The plug-in is included in
Workstation as a pipeline operation that
enables the SIMM model automatically to
be run immediately following processing.
Also see Analog, Force plate, Kinetics,
Pipeline, and Plug-in.
Single support A temporal parameter
used in gait analysis for the period of
time, or the percentage of the gait cycle,
where one foot supports the subject. Also
see Double support and Gait analysis.
SMPTE drop-frame timecode SMTPE
timecode that skips, or drops, two frame
numbers per minute, except at the tens
of the minute count. This resolves the
problem of incorrect synchronization of
timecode with clock time caused by
SMPTE timecode counting a full 30
frames per second while NTSC video
operates at 29.97 Hz. If unresolved, the
timecode would count 108 more frames
in one hour than actually occur in the
NTSC video in one hour. Also see SMPTE
timecode and Timecode.
SMPTE timecode The standard of
timecode defined by the Society of Motion
Picture and Television Engineers in the
USA, which is based on cameras
operating at multiples of 29.97 Hz.
During videotaping, frame numbers
corresponding to a particular video frame
are encoded in either LTC or VITC. Also
see EBU timecode, EIA, LTC, NTSC,
Timecode, and VITC.
.sp file Subject Parameters file. A text
file with extension .sp, which contains the
names and initial coordinates of markers
attached to a subject whose motion is
being captured or analyzed by
Workstation application software. The .sp
file is generated during the autolabel
calibration process and subsequently
used for labeling reconstructed data. By
default, .sp files are saved in the active
Session folder of the open database. Also
see Autolabel calibration, Subject and
Workstation.
Spike A point that lies to one side of an
otherwise smooth trajectory. A spike
appears as a sudden, dramatic rise or fall
in graph data. Spikes often occur as a
result of a poor reconstruction in a
particular frame and can be eliminated
using editing tools in Vicon application
software. Also see Frame, Point,
Reconstruction, and Trajectory.
Static calibration object A calibration
object used for setting the global
coordinate system in the capture volume.
An ergo calibration frame is one type of
static calibration object. Also see
Calibration kit, Calibration object,
Calibration volume, Ergo calibration
frame, and Global coordinate system.
Static trial A short data capture
(typically 3-5 seconds) during which the
subject stands in a stationary, neutral
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