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Glossary
© National Instruments Corporation G-15 IMAQ Vision for Visual Basic User Manual
ROI Region of interest.
(1) An area of the image that is graphically selected from a window
displaying the image. This area can be used focus further processing.
(2) A hardware-programmable rectangular portion of the acquisition
window.
ROI tools A collection of tools that enable you to select a region of interest from an
image. These tools let you select points, lines, annuli, polygons, rectangles,
rotated rectangles, ovals, and freehand open and closed contours.
rotational shift The amount by which one image is rotated relative to a reference image.
This rotation is computed relative to the center of the image.
rotation-invariant
matching
A pattern matching technique in which the reference pattern can be located
at any orientation in the test image as well as rotated at any degree.
S
saturation The amount of white added to a pure color. Saturation relates to the richness
of a color. A saturation of zero corresponds to a pure color with no white
added. Pink is a red with low saturation.
scale-invariant
matching
A pattern matching technique in which the reference pattern can be any size
in the test image.
segmentation function Fully partitions a labeled binary image into non-overlapping segments,
with each segment containing a unique object.
separation function Separates objects that touch each other by narrow isthmuses.
shift-invariant
matching
A pattern matching technique in which the reference pattern can be located
anywhere in the test image but cannot be rotated or scaled.
skeleton function Applies a succession of thinning operations to an object until its width
becomes one pixel.
smoothing filter Blurs an image by attenuating variations of light intensity in the
neighborhood of a pixel.
Sobel filter An edge detection algorithm that extracts the contours in gray-level values
using a 3 × 3 filter kernel.
spatial calibration Assigns physical dimensions to the area of a pixel in an image.