National Instruments IMAQ Vision for Measurement Studio User Manual
Page 102
Glossary
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IMAQ Vision for LabWindows/CVI User Manual
particle
A connected region or grouping of pixels in an image in which all pixels
have the same intensity level. Particles are also referred to as blobs or
objects.
pattern matching
The technique used to quickly locate a grayscale template within a
grayscale image
picture aspect ratio
The ratio of the active pixel region to the active line region. For standard
video signals like RS-170 or CCIR, the full-size picture aspect ratio
normally is 4/3 (1.33).
picture element
An element of a digital image. Also called pixel.
pixel
Picture element. The smallest division that makes up the video scan line.
For display on a computer monitor, a pixel's optimum dimension is square
(aspect ratio of 1:1, or the width equal to the height).
pixel aspect ratio
The ratio between the physical horizontal size and the vertical size of the
region covered by the pixel. An acquired pixel should optimally be square,
thus the optimal value is 1.0, but typically it falls between 0.95 and 1.05,
depending on camera quality.
pixel calibration
Directly calibrating the physical dimensions of a pixel in an image.
pixel depth
The number of bits used to represent the gray level of a pixel.
PNG
Portable Network Graphic. Image file format for storing 8-bit, 16-bit,
and color images with lossless compression (extension PNG).
power 1/Y function
Similar to a logarithmic function but with a weaker effect.
power Y function
See
Prewitt filter
Extracts the contours (edge detection) in gray-level values using a
3 x 3 filter kernel. See gradient filter.
probability function
Defines the probability that a pixel in an image has a certain gray-level
value.
proper-closing
A finite combination of successive closing and opening operations that you
can use to fill small holes and smooth the boundaries of objects.
proper-opening
A finite combination of successive opening and closing operations that you
can use to remove small particles and smooth the boundaries of objects.