Banner PresencePLUS P4 Series - Manual (Page 251)

pincushion distortion
A visual effect where the sides of an image appear to bulge
inward on all sides like a pincushion. Caused by an increase
in effective magnification, as points in the image move away
from the image center.
pixel
Acronym for picture element.
polarization
The restriction of the vibrations of light or magnetic field
vectors to one plane.
polarized lighting
The use of polarizing filters to remove specular reflections
from a scene to be viewed. Typically, one polarizing filter is
placed in front of the light source and a second filter is placed
over the receiver with the two filters offset in their polarizing
direction by 90 degrees.
preprocessing
Enhancement, transformation, or filtering of images before
processing.
R
recognition
A match between a description derived from an image and a
description obtained from a stored model or feature set.
region of interest (ROI)
The Region of Interest (ROI) is the area to be analyzed inside
user-defined boundaries.
repeatability
The degree to which repeated measurements of the same
quantity vary about their mean.
resolution
1. The smallest detectable change in position or size of an
object.
2. The closest distance between two objects (points) in an
image, identifiable as two separate objects rather than
one object.
S
shift register
An electronic circuit consisting of a series of storage locations
(registers). During each clock cycle, the information in each
location moves (shifts) into the adjacent location.
signal-to-noise ratio
The ratio of the maximum value of an output signal to the
standard deviation amplitude of the noise on the signal.
strobe light
A pulsed illumination source that generates short bursts of
high-intensity light.
sub-pixel resolution
Any technique resulting in a measurement with a resolution
(interpolated position of change) of less than one pixel.
T
template matching
Comparing a template with an object in an image. Usually
performed at the pixel level, as with a template correlation.
threshold
The intensity (specific pixel value) below which a stimulus
produces no effect or response. Often used to convert a gray
scale or analog image into a binary image.
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