National Instruments IMAQ Vision for LabWindows TM /CVI User Manual

Page 108

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Glossary

IMAQ Vision for LabWindows/CVI User Manual

G-12

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N

neighbor

A pixel whose value affects the value of a nearby pixel when an image is
processed. The neighbors of a pixel are usually defined by a kernel or a
structuring element.

neighborhood
operations

Operations on a point in an image that take into consideration the values of
the pixels neighboring that point.

NI-IMAQ

The driver software for National Instruments IMAQ hardware.

nonlinear filter

Replaces each pixel value with a nonlinear function of its surrounding
pixels.

nonlinear gradient filter

A highpass edge-extraction filter that favors vertical edges.

nonlinear Prewitt filter

A highpass, edge-extraction filter based on two-dimensional gradient
information.

nonlinear Sobel filter

A highpass, edge-extraction filter based on two-dimensional gradient
information. The filter has a smoothing effect that reduces noise
enhancements caused by gradient operators.

Nth order filter

Filters an image using a nonlinear filter. This filter orders (or classifies)
the pixel values surrounding the pixel being processed. The pixel being
processed is set to the Nth pixel value, where N is the order of the filter.

number of planes
(in an image)

The number of arrays of pixels that compose the image. A gray-level or
pseudo-color image is composed of one plane, while an RGB image is
composed of three planes (one for the red component, one for the blue,
and one for the green).

O

OCR

Optical Character Recognition. The ability of a machine to read
human-readable text.

OCV

Optical Character Verification. A machine vision application that inspects
the quality of printed characters.

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