Learning The Error Map; Learning The Correction Table; Setting The Scaling Method; Calibration Invalidation - National Instruments IMAQ Vision for Measurement Studio User Manual

Chapter 6 Calibration
Note A high score does not reflect the accuracy of your system.
IMAQ Vision for LabWindows/CVI User Manual
Also, adjust the range parameter to distinguish the dots from the
background.
3. Select another learning algorithm. When nonlinear lens distortion is
present, using perspective projection sometimes results in a low
learning score.

Learning the Error Map

An error map helps you gauge the quality of your complete system.
The error map returns an estimated error range to expect when a pixel
coordinate is transformed into a real-world coordinate. The transformation
accuracy may be higher than the value the error range indicates. Set the
element of the options parameter to
learnMap
map.

Learning the Correction Table

If the speed of image correction is a critical factor for your application, use
a correction table. The correction table is a lookup table stored in memory
that contains the real-world location information of all the pixels in the
image. The extra memory requirements for this option are based on the size
of the image. Use this option when you want to correct several images at a
time in your vision application. Set the
options parameter to

Setting the Scaling Method

Use the element of the options parameter to choose the appearance
method
of the corrected image. Select either
IMAQ_SCALE_TO_PRESERVE_AREA
scaling methods, see Chapter 3, System Setup and Calibration, in the IMAQ
Vision Concepts Manual.

Calibration Invalidation

Any image processing operation that changes the image size or orientation
voids the calibration information in a calibrated image. Examples of
functions that void calibration information include
,
imaqScale() imaqArrayToImage()
learnTable
to learn the correction table.
TRUE
IMAQ_SCALE_TO_FIT
. For more information about the
, and
6-8
to learn the error
TRUE
element of the
or
imaqResample()
.
imaqUnwrap()
,
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