© 2007-2012 Thorlabs GmbH
91Operating Instruction
4.2.5
Measurement Warnings and Errors
During capturing of the camera image and its subsequent analysis some errors may
arise which needs to be recognized. Read the error message carefully and find a
way to remove the reason of it.
NOTE
Measurement results are unreliable if an error or warning is indicated within the
status window.
Error List
Zernike Fit failed! Insufficient spots detected.
This error occurs if the number of detected spots within the pupil is lower than the
number of Zernike modes to be calculated in the least square Zernike fit.
To prevent this error
check the analyzed beam that it is properly aligned and its intensity dominates the
ambient light level and/or
increase the pupil diameter within the Pupil Definitions Setup panel and/or
reduce the number of Zernike orders in the Zernike Fit Setup panel
increase the camera resolution within the Camera Settings Setup in case the
pupil diameter is close to the image dimensions
Low Spot Count within pupil may cause reduced Zernike accuracy!
Even if the number of detected spots within the pupil exceeds the minimum required
number, there may occur an increased calculation error during the Zernike Fit,
especially in case of high orders. Therefore, higher order fits (up to order 7-10)
require an extra spot count of about 30%.
To prevent this warning
check the analyzed beam that it is properly aligned and its intensity dominates the
ambient light level and/or
increase the pupil diameter within the Pupil Definitions Setup panel and/or
reduce the number of Zernike orders in the Zernike Fit Setup panel
increase the camera resolution within the Camera Settings Setup in case the
pupil diameter is close to the image dimensions
Pupil badly filled with spots, may cause reduced Zernike accuracy!
The pupil area is not properly filled with detected spots up to its full diameter.
Because the number of detected spots is defined by the selected camera resolution,
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