Varifocal lens:
is a type of manual zoom lens with a small zoom ratio (ranging
between 4mm to 12mm depending on brand). It is used when the focal
length of the lens needs to be fine tuned to meet the requirements of
the actual scene.
Video head:
is an internal part of a VCR which rotates very rapidly and
writes the video signal on to the video tape during recording while
reading the video signal from the tape during playback.
Vertical resolution:
is the number of horizontal lines which can be resolved in a
picture. It is limited by the television scanning method - NTSC, PAL
etc.
Vertical shift register:
is a part of the interline transfer CCD chip and is placed in
between every column of pixels. At the end of each frame the charge from
the pixels are sent to the vertical shift register (VSR) and then row by
row to the horizontal shift register.
Vertical streaking:
is a type of picture distortion that occurs due to overloading
of the pixels in an interline transfer chip. It appears as vertical
streaks above and below the bright part of the picture.
VHS Victor Home System:
is a type of popular recording format used in video cassette
recorders. The other type of formats are betamax, 8mm, system 2000 and
U-matix (professional).
Vibration sensor:
is a type of device which can be activated by vibrations in a
pre determined zone and can be interfaced with a switcher to switch the
nominated camera for extended viewing.
Video amplifier:
is a type of amplifier used to boost the strength of a video
signal.
Video cassette recorder:
is a device which can record (or playback) video and audio
signals on a magnetic tape housed in a cassette.
Video distribution amplifier:
is a type of amplifier used not only to boost the strength but
also create multiple outputs of the video signal.
Video intercom:
is a door entry system which uses both audio and video to
communicate and/or control movement of people.
Video monitoring:
is a new trend which uses video to monitor remote sites in any
part of the world. The video images are transmitted through the
telephone network.
Video motion detector:
is a device which can detect unwanted movement in the picture
and then generate an alarm. |