National Instruments NI Vision PCI-1409, Руководство пользователя, Страница: 34 / 40

Glossary
© National Instruments Corporation G-7 NI PXI/PCI-1409 User Manual
MTBF Mean time between failure.
mux Multiplexer. A switching device with multiple inputs that selectively
connects one of its inputs to its output.
N
NI-IMAQ Driver software for National Instruments image acquisition hardware.
noninterlaced A video frame where all the lines are scanned sequentially, instead of
divided into two frames as in an interlaced video frame.
NTSC National Television Standards Committee. The committee that developed
the color video standard used primarily in North America, which uses
525 lines per frame.
See also PAL.
number of planes
(in an image) The number of arrays of pixels that compose the image. A gray-level or
pseudo-color image is composed of one plane, while an RGB image is
composed of three planes (one for the red component, one for the blue,
and one for the green).
NVRAM Nonvolatile RAM. RAM that is not erased when a device loses power or is
turned off.
P
PAL Phase Alternation Line. One of the European video color standards. PAL
uses 625 lines per frame.
See also NTSC.
PCI Peripheral Component Interconnect. A high-performance expansion bus
architecture originally developed by Intel to replace ISA and EISA. PCI
offers a theoretical maximum transfer rate of 132 Mbytes/s.
PCLK Pixel clock signal. Times the sampling of pixels on a video line.
picture aspect ratio The ratio of the active pixel region to the active line region. For standard
video signals like RS-170 or CCIR, the full-size picture aspect ratio
normally is 4/3 (1.33).
pixel aspect ratio The ratio between the physical horizontal size and the vertical size of the
region covered by the pixel. An acquired pixel should optimally be square,
thus the optimal value is 1.0, but typically it falls between 0.95 and 1.05,
depending on camera quality.