Glossary
©NationalInstruments Corporation G-5 IMAQVision for LabWindows/CVI User Manual
cross correlation A technique that compares the similarity of two images or parts of an
image.You can use cross correlation to find the optimal position where
similarity exists.
D
Danielssonfunction Similarto the distance functions, but with more accurate results.
dB Decibel. The unit for expressinga logarithmic measure of the rati o of
twosignal levels: dB = 20log10 V1/V2, for signals in volts.
defaultsetting Adefault parameter value recorded in the driver. In manycases, the default
input of a control is a certain value(often 0).
definition Thenumber of values a pixel can take on, which is the number of colors or
shades that you can seein the image.
dendrite Branchesof the skeletonof an object.
densitometry Intensity informati on about an image or regions of an image. Typical
measurements include minimum, maximum, and mean intensity values
asw ell as the standard deviationo f the intensity values.
densityfunction Foreach gray level in a linear histogram, the function gives the number of
pixelsin the image that h avethe same gray level.
differentiationfilter Extracts the contours (edge detection) in gray level.
digitali mage An image f (x, y) that has been converted into a discrete number of pixels.
Both spatialcoordinates and brightnessare specified.
dilation Increases the size of an object along its boundary and removes tiny holes
in the object.
distancecalibration Determination of the physical dimensions of a pixel by defining the
physical dimensions of a line in the image.
distancefunction Assigns to each pixelin an object a gray-level value equal to its shortest
Euclidean distance from the border of the object.
driver Softwarethat controls a specific hardware device, such as an IMAQ or
DAQdevice.