User`s manual

124 • Glossary of Terms PC2-CamLink User's Manual
Frame buffer
An area of memory used to hold a frame of image data. A frame buffer may exist on the
acquisition hardware or be allocated by the acquisition hardware device driver in host system
memory.
Grab
Acquiring an image frame by means of a frame grabber.
Grayscale
In image processing, the range of available brightness levels, displayed in shades of gray. In
an 8-bit system, the gray scale contains values from 0 to 255.
Host
Refers to the computer system that supports the installed frame grabber.
Interlaced
Describing the standard television method of raster scanning in which the image is the
product of two fields, each of which is made up of the image's alternate lines (i.e., one field is
comprised of lines 1, 3, 5, etc., and the other is comprised of lines 2, 4, 6, etc.)
Low Pass Filter
A filter that blocks high frequencies and allows lower frequencies to pass through. Used to
limit undesirable analog information (such as high frequency video noise) before converting
to digital data.
NTSC
National Television Systems Committee. Color TV standard used in North America and other
countries. The interlaced video signal is composed of a total of 525 video lines at a frame rate
of 30 Hz.
PAL
Phase Alteration by Line. Color TV standard used in most of Europe and other countries. The
interlaced video signal is composed of a total of 625 video lines at a frame rate of 25 Hz.
PCI
Peripheral Component Interconnect. The PCI local bus is a 32-bit high performance
expansion bus intended for interconnecting add-in boards, controllers, and processor/memory
systems.
Pixel
A contraction of "picture element". The number of pixels describes the number of digital
samples taken of the analog video signal. The number of pixels per video line by the number
of active video lines describes the acquisition image resolution. The binary size of each pixel