National Instruments NI-IMAQ User Manual

Page 45

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Glossary

© National Instruments Corporation

G-3

NI-IMAQ for IEEE-1394 Cameras User Manual

driver

Software that controls a specific hardware device, such as an IMAQ or
DAQ device.

E

external trigger

A voltage pulse from an external source that triggers an event such as
A/D conversion.

F

field

For an interlaced video signal, a field is half the number of horizontal lines
needed to represent a frame of video. The first field of a frame contains all
the odd-numbered lines, the second field contains all of the even-numbered
lines.

frame

A complete image. In interlaced formats, a frame is composed of two fields.

function

A set of software instructions executed by a single line of code that may
have input and/or output parameters and returns a value when executed.

G

gamma

The nonlinear change in the difference between the video signal’s
brightness level and the voltage level needed to produce that brightness.

GUI

Graphical user interface. An intuitive, easy-to-use means of
communicating information to and from a computer program by means
of graphical screen displays. GUIs can resemble the front panels of
instruments or other objects associated with a computer program.

H

hardware

The physical components of a computer system, such as the circuit boards,
plug-in boards, chassis, enclosures, peripherals, and cables.

hue

Represents the dominant color of a pixel. The hue function is a continuous
function that covers all the possible colors generated using the R, G, and B
color spectrum. See also RGB.

Hz

Hertz. Frequency in units of 1/second.

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