Glossary
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National Instruments Corporation
G-5
IMAQ Vision 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
Danielsson function
Similar to the distance functions, but with more accurate results.
dB
Decibel. The unit for expressing a logarithmic measure of the ratio of
two signal levels: dB = 20log10 V1/V2, for signals in volts.
default setting
A default parameter value recorded in the driver. In many cases, the default
input of a control is a certain value (often 0).
definition
The number of values a pixel can take on, which is the number of colors or
shades that you can see in the image.
dendrite
Branches of the skeleton of an object.
densitometry
Intensity information about an image or regions of an image. Typical
measurements include minimum, maximum, and mean intensity values
as well as the standard deviation of the intensity values.
density function
For each gray level in a linear histogram, the function gives the number of
pixels in the image that have the same gray level.
differentiation filter
Extracts the contours (edge detection) in gray level.
digital image
An image f (x, y) that has been converted into a discrete number of pixels.
Both spatial coordinates and brightness are specified.
dilation
Increases the size of an object along its boundary and removes tiny holes
in the object.
distance calibration
Determination of the physical dimensions of a pixel by defining the
physical dimensions of a line in the image.
distance function
Assigns to each pixel in an object a gray-level value equal to its shortest
Euclidean distance from the border of the object.
driver
Software that controls a specific hardware device, such as an IMAQ or
DAQ device.
