Glossary
©NationalInstruments Corporation G-15 IMAQVision for LabWindows/CVI User Manual
particle A connected regionor grouping of pixels in an image in which all pixels
havethe 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 activepixel region to the active line region. For standard
video signals likeRS-17 0o rCCIR, the full -sizepict ure aspect ratio
normally is 4/3(1.33).
picture element Anelement of a digital image. Also called pixel.
pixel Pictureelement. The smallest division that makes up the video scan line.
Fordisplay on a computer m onitor,a pixel's optimum dimension is squ are
(aspect ratio of 1:1, or the width equal to the height).
pixelaspect ratio The ratio between the physical horizontal size and the vertical size of the
regioncovered by the pixel. An acquired pixel should optimally be square,
thus the optimal valueis 1.0, but typically it falls between 0.9 5 and 1.05,
depending on camera quality.
pixelcalibration Directlycalibrating the physical dimensions of a pixel in an image.
pixeldepth The number of bits used to represent the gray levelof a pixel.
PNG Portable NetworkG raphic. Image fileformat for storing 8-bit, 1 6-bit,
and colorimages withlossless compression (extension PNG).
power1/Y function Similar to a logarithmic function but with a weaker effect.
powerY function Seeexponential function.
Prewittfilter Extractst he contours (edge detection) in gray-levelvalues using a
3x3filterkernel.Seegradient filter.
probability function Definesthe probab ility that a pixelin an image has acer tain gray-level
value.
proper-closing Afinite combination of successive closing and opening operations that you
can uset o fillsmall holes and smooth the boun daries of objects.
proper-opening Afinite combination of successive opening and closing operations that you
can uset o removesmall particles and smooth the boundari esof objects.