National Instruments IMAQ Vision, User Manual

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Glossary
IMAQ Vision for LabWindows/CVI User Manual G-6 ni.com
E
edge Defined by a sharp change (transition) in the pixel intensities in an image
or along an array of pixels.
edge contrast The difference between the average pixel intensity before and the average
pixel intensity after the edge.
edge detection Any of several techniques to identify the edges of objects in an image.
edge hysteresis The difference in threshold level between a rising and a falling edge.
edge steepness The number of pixels that corresponds to the slope or transition area of an
edge.
energy center The center of mass of a grayscale image. See center of mass .
entropy A measure of the randomness in an image. An image with high entropy
contains more pixel value variation than an image with low entropy.
equalize function See histogram equalization .
erosion Reduces the size of an object along its boundary and eliminates isolated
points in the image.
Euclidean distance The shortest distance between two points in a Cartesian system.
exponential and
gamma corrections Expand the high gray-level information in an image while suppressing
low gray-level information.
exponential function Decreases brightness and increases contrast in bright regions of an image,
and decreases contrast in dark regions of an image.
F
feature A specific pattern of pixels in an image.
FFT Fast Fourier Transform. A method used to compute the Fourier transform
of an image to get frequency information.
fiducial A reference pattern on a part that helps a machine vision application find
the part's location and orientation in an image.