National Instruments IMAQ Vision for Measurement Studio User Manual

Page 94

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Glossary

© National Instruments Corporation

G-7

IMAQ Vision for LabWindows/CVI User Manual

form

Window or area on the screen on which you place controls and indicators
to create the user interface for your program.

Fourier spectrum

The magnitude information of the Fourier transform of an image.

Fourier transform

Transforms an image from the spatial domain to the frequency domain.

frequency filters

Counterparts of spatial filters in the frequency domain. For images,
frequency information is in the form of spatial frequency.

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.

G

gamma

The nonlinear change in the difference between the video signal's
brightness level and the voltage level needed to produce that brightness.

gauging

Measurement of an object or distances between objects.

Gaussian filter

A filter similar to the smoothing filter, but using a Gaussian kernel in the
filter operation. The blurring in a Gaussian filter is more gentle than a
smoothing filter.

gradient convolution
filter

See gradient filter.

gradient filter

Extracts the contours (edge detection) in gray-level values. Gradient filters
include the Prewitt and Sobel filters.

gray level

The brightness of a pixel in an image.

gray-level dilation

Increases the brightness of pixels in an image that are surrounded by other
pixels with a higher intensity.

gray-level erosion

Reduces the brightness of pixels in an image that are surrounded by other
pixels with a lower intensity.

grayscale image

An image with monochrome information.

grayscale
morphology

Functions that perform morphological operations on a gray-level image.

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