System information

Glossary-14 Vicon MX Hardware System Reference
limp index is exactly one. Also see Double
support, Gait analysis, and Single
support.
Live 3D Workspace See
3D Workspace.
Local coordinate system A coordinate
system whose origin (0,0,0) and axes
(x,y,z) are fixed with respect to a
particular segment or element in a
kinematic model, as opposed to the
global origin and axes directions. Also see
Capture volume, Global coordinate
system, Kinematic model, Volume origin,
and Workspace axes.
Low-pass filter A filter that permits
only signal components below a specified
frequency to be passed through. Some
Vicon cameras are fitted with low-pass
absorptive optical filters that allow low-
frequency light from Vicon strobe units to
pass. Also see Band-pass filter,
MX Camera, and Strobe unit.
LTC Longitudinal Timecode. A form of
timecode compatible with standard audio
channels so that they can be recorded
onto an audio tape track or an audio track
on video tape. Also see EBU timecode,
SMPTE timecode, Timecode, and VITC.
M
Marker 1) A sphere, hemisphere, or
disk coated with a highly retroreflective
material which is attached to a subject or
object whose motion is being captured or
analyzed in a Vicon system. The Vicon
cameras are designed to capture the
pattern of light reflected from such a
marker and convert it into an image that
represents the position and radius of the
marker. Also see Subject and Object.
2) The 3D representation of a
retroreflective marker generated by Vicon
application software (also referred to as a
model marker). The expected location of
all markers attached to a subject whose
motion is being captured or analyzed in a
Vicon system is defined in the kinematic
model (.vst or .vsk file) for the subject or
in the associated marker (.mkr) file.
These can be visualized as elements of
the 3D representation of the subject. Also
see Kinematic model, .mkr file, Subject,
.vsk file, and .vst file.
Marker covariance A 3D representa-
tion in Vicon application software of how
much a marker is allowed to move in
relation to its associated segment or
joint, based on the subject’s RoM trial.
Also see Marker, Range of Motion (RoM)
trial, and Segment.
Mask See Camera mask.
MCam A high-resolution, high-speed
digital CMOS sensor camera used in a
Vicon V-series system. There are Mcam
cameras that lock to PAL or NTSC video
systems and run in synchronous
multiples of their base frame rate. MCam
cameras can be integrated into a
Vicon MX system using the MX Bridge
unit. Also see CMOS, MX Bridge, NTSC,
PAL, Vicon MX, and Vicon V-series
system.
MCam2 A high-resolution, high-speed
digital CMOS sensor camera used in a
Vicon V-series system. MCam2 cameras
can be integrated into a Vicon MX system
using the MX Bridge unit. Also see CMOS,
MX Bridge, and Vicon V-series system.
.mkr file Marker file. A text file with
extension .mkr, which specifies the labels
to be used on the markers displayed in
the 3D Workspace in Vicon application
software and indicates the placement of
the physical markers on the subject or
object whose motion is being captured or
analyzed in a Vicon system. The file also
can include information about body
segments, modeled data, and how the
subject will be displayed in the
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