System information

Glossary-20 Vicon MX Hardware System Reference
Point A location in space specified by
3D coordinates. A trajectory (or segment
of a trajectory) consists of a time-series
of points. A point is stored in a .c3d file as
three spatial coordinates and a residual,
identified by a label. Points may
represent the measured positions of real
markers. In some Vicon application
software, points may be virtual (created
by modeling). The terms point and
marker are often used interchangeably.
Also see .c3d file, Label, Marker, and
Virtual point.
Polygon Vicon application software for
biomechanics visualization and reporting,
which models bones, muscles, and
ligaments. Polygon functionality can be
extended with plug-in modules. Also see
OLGA and Plug-in Gait.
Post-Triggering A feature in some
Vicon application software that enables a
Vicon system to capture events that have
already happened. This is useful, for
example, for subjects whose motion is
difficult to predict, such as animals and
children.
Primary selection The first of multiple
selected objects (such as markers or
graph plots). Some tools or processes in
some Vicon application software operate
solely on the primary selection. Also see
Secondary selection.
Progressive video Also known as
progressive scan. A method for
constructing a video image by drawing
the lines of each frame in sequence. The
entire image is constructed every frame.
Also see Composite video signal.
.protocol file An XML file with
extension .protocols, which contains
configuration settings for customized
workflow protocols created in the
Protocols status pane in Vicon Nexus.
Also see Nexus.
R
Range of Motion (RoM) trial A short
dynamic trial (typically 15-30 seconds)
during which the subject moves his or her
limbs and joints to enable Vicon
application software to determine the
location of and measurements between
key markers and to assign labels to the
reconstructed 3D markers. This type of
dynamic trial is required for the subject
calibration process.
During a RoM trial, the subject moves
each limb and joint to be captured
through its full range of motion at least
once. For entertainment applications, the
movements included in a RoM trial should
match any moves that will be included in
the planned data captures. For life
sciences applications, the movements
included in a RoM trial depend on factors
such as the subject’s physical
capabilities; if the subject is not able to
perform a RoM trial, use the full subject
calibration process in Plug-in Gait
instead. Also see Dynamic trial, Plug-in
Gait, Subject calibration, Workstation,
and Vicon iQ.
Real-time processing The process of
converting raw, 2D motion data being
streamed live by Vicon cameras into 3D
data. Also see RealTime Engine (RTE) and
Offline processing.
RealTime Engine (RTE) Vicon
application software that produces 3D
data based on the raw motion data
acquired by Vicon MX or V-series
cameras. The RTE (known as Tarsus in
Vicon V-series systems) reconstructs,
labels, and optionally kinematically fits
this real-time motion data, which can
then be viewed and incorporated in Vicon
iQ, Polygon, or third-party visualization
software. Also see Polygon, Tracker,
Vicon iQ, and Workstation.
MXhardware_Reference.book Page 20 Thursday, September 7, 2006 11:36 AM