Glossary
G-8
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pixel clock
Divides the incoming horizontal video line into pixels.
pixel count
The total number of pixels between two horizontal synchronization signals
(HSYNCs). The pixel count determines the frequency of the pixel clock.
PLL
Phase-locked loop. Circuitry that provides a very stable pixel clock that is
referenced to another signal, such as an incoming horizontal
synchronization signal (HSYNC).
PXI
PCI eXtensions for Instrumentation. An open specification that builds on
the CompactPCI specification by adding instrumentation-specific features.
R
relative accuracy
A measure in LSB of the accuracy of an ADC; it includes all nonlinearity
and quantization errors but does not include offset and gain errors of the
circuitry feeding the ADC.
resolution
(1) The number of rows and columns of pixels. An image composed of
m
rows and
n
columns has a resolution of
m
×
n
. This image has
n
pixels
along its horizontal axis and
m
pixels along its vertical axis. (2) The
smallest signal increment that can be detected by a measurement system.
Resolution can be expressed in bits, proportions, or a percentage of full
scale. For example, a system has 12-bit resolution, one part in
4,096 resolution, and 0.0244 percent of full scale.
RGB
Color encoding scheme using red, green, and blue (RGB) color information
where each pixel in the color image is encoded using 32 bits: 8 bits for red,
8 bits for green, 8 bits for blue, and 8 bits for the alpha value (unused).
ribbon cable
A flat cable in which the conductors are side by side.
ROI
Region of interest. (1) An area of the image that is graphically selected
from a window displaying the image. This area can be used focus further
processing. (2) A hardware-programmable rectangular portion of the
acquisition window.
RSE
Referenced single-ended. All measurements are made with respect to a
common reference measurement system or a ground. Also called a
grounded measurement system.