National Instruments IMAQTM 用户手册

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页码 121
Glossary
© National Instruments Corporation
G-15
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.