System information

Vicon MX Hardware System Reference Glossary-11
separation. Also see Frame rate and View
pane.
Fullscreen preview A type of view
pane in some Vicon application software
in which the unthresholded, full grayscale
image from the entire CMOS sensor in an
MX camera is displayed. Also see CMOS
and Grayscale blob.
G
Gain A multiplicative increase (or
decrease) in a voltage or digital signal by
a specified magnitude. Adjusting the gain
in a Vicon camera increases or decreases
the intensity of a marker displayed in the
workspace. Also see Marker and
Workspace.
Gait analysis The study of human
movement for medical purposes. Vicon
application software can record and
analyze such data to generate kinematic
and kinetic data. Also see Force plate,
Kinematics and Kinetics.
Gap An absence of one or more
reconstructions for a marker trajectory. A
gap can occur when a marker is fully
occluded (or blocked) from the camera’s
view during motion capture, thus
resulting in missing data for that marker
during that period of time. Gaps can be
filled using editing tools in Vicon
application software. Also see
Reconstruction, Tail, and Trajectory.
Genlock The process of sync generator
locking. A genlock device enables a
composite video signal from a master
source to be introduced to the subject
sync generator. The generator to be
locked has circuits to isolate vertical
drive, horizontal drive, and subcarrier.
Vicon systems provide genlock
functionality to synchronize Vicon
cameras to the scan rate of incoming
video signals from an external PAL,
SECAM, or NTSC video source integrated
in the Vicon system. A Vicon MX system
also can act as the synchronization
master. Also see Datastation, MX Control,
NTSC, PAL, and SECAM.
Ghost marker Also known as ghost
trajectory. A spurious marker trajectory
produced by the reconstruction process.
A ghost marker is a false reconstruction
that appears as an additional trajectory
very close to an existing one over a short
duration. Also see Reconstruction and
Trajectory.
Global coordinate system The
coordinates defining the origin (0,0,0)
and the axes (x,y,z) of the world in the
context of the Vicon capture volume. Also
see Capture volume, Volume origin and
Workspace axes.
.gpo file General Purpose Output file.
An XML file with extension .gpo, which
specifies the characteristics of a
synchronization signal through the GPO
ports of an MX Control or MX Ultranet
unit. For example, .gpo files supplied with
the Vicon Reference Video system option
specify the relationship of the frame rate
of a connected reference video camera
with that of the MX cameras. Also see
Frame rate, MX Camera, MX Control,
MX Ultranet, and Reference video.
Grayscale blob In Vicon MX systems,
the raw, 2D grayscale data MX cameras
generate for reflections from objects in
the capture volume. Such data is
submitted as candidates to MX centroid-
fitting algorithms to determine which are
likely to be markers. Also see Blob and
Centroid fitting.
Grayscale data In Vicon MX, the
complete pixel and line information for a
grayscale blob. Also see Grayscale blob.
MXhardware_Reference.book Page 11 Thursday, September 7, 2006 11:36 AM