System information

Vicon MX Hardware System Reference Glossary-7
D
Data acquisition The process by which
Vicon motion capture and analysis
systems convert information from real-
world sources to digital form in which it
may be stored, manipulated, analyzed,
and displayed. Also see Data streaming
and Motion capture.
Data capture See Motion capture and
Movie capture.
Data file Related pieces of data
organized in a specific manner. Data files
contain information but not instructions
or programs.
Data streaming The passing of real-
time motion data from some Vicon
application software to Vicon or third-
party visualization software. Also see
Data acquisition, Motion capture, and
Visualization software.
Datastation In Vicon V-series systems,
a Vicon hardware unit that captures and
synchronizes all Vicon camera and analog
data. This unit provides the link between
the Vicon cameras, the host PC running
the Vicon application software, and any
third-party analog devices. Also see
Analog, Host PC, and Vicon V-series
system.
DCAM Instrumentation and Industrial
Control Working Group (IIDC) 1394-
based Digital Camera Specification. A
standard for digital cameras that output
uncompressed image data without audio
and are to be connected to a computer
using an IEEE 1394 connector. The Vicon
Reference Video option supports the
Basler range of DCAM cameras. Also see
IIDC 1394 and Reference video.
Degree of freedom (DOF) An
indication of how freely a joint is able to
move (translate or rotate) in respect to
its parent segment. This is expressed as
the minimum number of coordinates
required to completely specify the
rotational (Rx, Ry, and Rz) and/or
translational (Tx, Ty, Tz) movement of the
joint.
0 DOF indicates a fixed joint with no
rotational or translation freedom. 1 DOF
indicates a hinge joint with rotational
freedom around a single axis. 2 DOF
indicates a universal joint with two
rotational degrees of freedom around two
orthogonal axes. 3 DOF indicates a ball-
and-socket joint with full rotational (but
not translational) freedom. 6 DOF
indicates a free joint with full
translational as well as rotational
freedom. Also see Rotation and
Translation.
Depth of field The distance between
the nearest object in focus and the
furthest object in focus within a scene as
viewed by a particular camera lens.
Outside this area, moving towards or
away from the lens, the focus becomes
progressively less sharp and the image
appears out of focus. Depth of field varies
with subject-to-camera distance, lens
focal length, and lens aperture. Also see
Aperture and Focal length.
DOF See Degree of freedom (DOF).
Dolly The moving of a camera along a
horizontal axis closer to (dolly in) or
further from (dolly out) the subject. Also
see Pan, Tilt, and Truck.
Dongle A hardware security device
connected to an input/output port on a
computer to permit the use of licensed
software on that computer. Vicon
application software is licensed using a
HASP dongle, which must be plugged into
the appropriate port (parallel or USB) on
the computer while the software is in use.
Double support A temporal parameter
used in gait analysis for the period of
time, or the percentage of the gait cycle,
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