Data Translation DT3152-LS, User Manual

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Principles of Operation
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Input Look-Up Table
An input look-up table (ILUT) allows you to change the value of an
incoming pixel. When the ILUT gets an input pixel value, it retrieves
the output value for that particular pixel from the ILUT and passes
the output value to the frame (region of interest). Pixel values range
from 0 to 255. The DT3152-LS frame grabber board supports one
ILUT.
Using software, you can specify the relationship between the pixel
input value and the ILUT output value by loading the ILUT with
different processing setups. For example, you can pass an image
unaltered (the default setting, known as identity), or you can perform
pixel point operations, such as image multiplication and division,
intensity correction, and reverse-video, before passing the image on.
As an example, assume that the ILUT is loaded with the identity
pattern. An input value of 0 (black in monochrome mode) has an
output value of 0 (black in monochrome mode). An input value of 1
has an output value of 1. An input value of 2 has an output value of 2,
and so on, up to an input value of 255 (which has an output value of
255 or white in monochrome mode).
As another example, if you load the ILUT with an inverse or negative
pattern, an input of 0 has an output value of 255, an input value of 1
has an output pattern of 254, and so on, up to an input value of 255
(which has an output value of 0 or black in monochrome mode).
Note that in addition to ILUTs, passthru operations make use of
passthru LUTs. For more information about passthru LUTs, refer to
page 50 .