National Instruments IMAQTM 用户手册
Glossary
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G-5
edge steepness
The number of pixels that corresponds to the slope or transition area
of an edge.
of an edge.
energy center
The center of mass of a grayscale image. See
equalize function
erosion
Reduces the size of an object along its boundary and eliminates isolated
points in the image.
points in the image.
exponential and
gamma corrections
gamma corrections
Expand the high gray-level information in an image while suppressing low
gray-level information.
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.
and decreases contrast in dark regions of an image.
F
FFT
Fast Fourier Transform. A method used to compute the Fourier transform
of an image.
of an image.
fiducial
A reference pattern on a part that helps a machine vision application find
the part's location and orientation in an image.
the part's location and orientation in an image.
Fourier transform
Transforms an image from the spatial domain to the frequency domain.
frequency filters
The counterparts of spatial filters in the frequency domain. For images,
frequency information is in the form of spatial frequency.
frequency information is in the form of spatial frequency.
ft
Feet.
function
A set of software instructions executed by a single line of code that may
have input and/or output parameters and returns a value when executed.
have input and/or output parameters and returns a value when executed.
G
gamma
The nonlinear change in the difference between the video signal’s
brightness level and the voltage level needed to produce that brightness.
brightness level and the voltage level needed to produce that brightness.
gradient convolution
filter
filter