46
Glossary
Following is an explanation of some of the terms used in this guide which may be unfamiliar or which
were not explained in the manual itself. Further information can be obtained by referring to other
commercially-available publications.
Aspect
The ratio between an image's length and its height. HDTV
images have an aspect of 16:9 and appear elongated. The
aspect for standard images is 4:3.
Colour temperature
The temperature of an object which is emitting light. If the
colour temperature is high, the colors tend to take on a
bluish tinge. If the colour temperature is lower, the colors
tend to take on a reddish tinge.
Component video
Video signals which have the video brightness signals and
color signals separated, in order to provide better image
quality.
In high-definition TV (HDTV), it refers to images which
consist of three independent signals: Y (luminance signal),
and Pb and Pr (color difference signals).
Composite video
Video signals which have the video brightness signals and
color signals mixed together. The type of signals
commonly used by household video equipment (NTSC ,
PAL and SECAM formats).
Video signals which consist of a carrier signal Y
(luminance signal) within the color bar signal, and a
chroma or color signal (CbCr).
Contrast
The relative brightness of the light and dark areas of an
image can be increased or decreased in order to make text
and graphics stand out more clearly, or to make them
appear softer.
Cool-down
This is the process by which the projector's lamp is cooled
down after it has become hot through use. It is carried out
automatically when the [Power] button on either the
remote control or the projector's control panel has been
pressed to turn off the projector. Do not disconnect the
power cable while cool-down is in progress, otherwise the
cool-down process will not work properly. If the cool-
down period is not allowed to finish normally, the
projector's lamp and internal components will remain at
high temperatures, and this may shorten the useful life of
the lamp or cause problems with the operation of the
projector. The cool-down period lasts for about 5 minutes.
The actual time will vary depending on the external air
temperature.
Gain
The adjustment of minute changes in color that occur as
result of factors such as differences in the equipment used
to display images. It adjusts the coloration in brighter
ranges separately for R, G and B components.
Gamma
The adjustment of minute changes in color that occur as
result of factors such as differences in the equipment used
to display images. It adjusts the coloration in intermediate
ranges separately for R, G and B components.
HDTV
An abbreviation for High-Definition Television. It refers to
high-definition systems which satisfy the following
conditions.
• Vertical resolution of 750p or 1125i or greater
(p = progressive , i = interlaced )
• Screen aspect of 16:9
• Dolby Digital audio reception and playback (or output)
Interlace
A method of image scanning whereby the signal
bandwidth used is approximately half that required for
sequential scanning when images with the same still
picture resolution are broadcast.
NTSC
An abbreviation for National Television Standards
Committee, and a format for ground-based analogue
colour television broadcasts. This format is used in Japan,
North America and Central and South America.
Offset
The adjustment of minute changes in color that occur as
result of factors such as differences in the equipment used
to display images. It adjusts the coloration in darker ranges
separately for R, G and B components.
PAL
An abbreviation for Phase Alternation by Line, and a
format for ground-based analogue colour television
broadcasts. This format is used in Western European
countries except France, and also in Asian countries such
as China and in Africa.
Progressive
A method of image scanning whereby the image data from
a single image is scanned sequentially from top to bottom
to create a single image.
Refresh rate
The light-emitting element of a display maintains the same
luminosity and color for an extremely short time. Because
of this, the image must be scanned many times per second
in order to refresh the light emitting element. The number
of refresh operations per second is called the "refresh rate",
and is expressed in hertz (Hz).
S-Video
A video signal which has the luminance component and
color component separated in order to provide better image
quality.
It refers to images which consist of two independent
signals: Y (luminance signal), and C (color signal).
SDTV
An abbreviation for Standard Definition Television. It
refers to standard television systems which do not satisfy
the conditions for HDTV .
