Banner PresencePLUS P4 COLOR Series - Manual (Page 377)

distortion
Undesired change in the shape of an image or waveform from
the original object or signal.
edge
A change in pixel values exceeding some threshold between
two adjacent regions of relatively uniform values. Edges
correspond to changes in brightness corresponding to a
discontinuity in surface orientation, reflectance, or illumination.
f/stop (or f/number
Ratio of the focal length of a lens to the diameter of its opening.
Increasing or decreasing an exposure by one f/stop doubles or
halves the amount of light allowed through the lens.
feature
Any characteristic descriptive of an image or a region in an
image.
feature extraction
The process of generating a set of descriptors or characteristic
attributes from an image.
fiducial mark
A mark defining a datum point or standard of positional
reference used as a basis for calculation or measurement.
field of view (FOV)
The area of object space imaged at the focal plane of a lens.
fluorescent lamp
A lamp that produces light by exciting a phosphor with a
plasma, with the phosphor re-emitting the energy as light.
focal length
The distance from a lens’ principal point to the corresponding
focal point. Also referred to as the equivalent focal length and
the effective focal length.
front lighting
An arrangement in which the object is illuminated and viewed
from the same side.
G
gradient magnitude
The rate-of-change of pixel intensities over a small local
neighborhood.
gray scale
Standardized variations of values from white, through shades
of gray, to black in a digitized image with black assigned the
value of zero and white the value of 255.
H
halogen
A gas, such as iodine, placed inside an incandescent lamp to
gather the evaporated filament off the bulb and redeposit it
back onto the filament.
high pass filter
A processing operation that enhances high frequencies (and
attenuates low frequencies).
histogram
Frequency counts of the population of pixels of each intensity
(gray level) or other characteristic populations in an image.
I
incandescent
Thermal generation of light, usually through radiant filaments
in a bulb.
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