THORLABS WFS20-14AR, Operation Manual

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© 2007 - 2018 Thorlabs
5 Operating Instruction
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5.5 Measurement Warnings and Errors
Status Bar
During image capture and analysis by the camera, some errors may occur that need to be rec-
ognized and addressed. Read the error message carefully and find a way to remove the cause
of the error.
Note
Measurement results are unreliable if an error or warning is indicated within the status window.
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 for proper alignment and make sure that its intensity dominates
the ambient light level and/or
·
Increase the pupil diameter Pupil Definitions panel and/or
·
Reduce the number of Zernike orders in the Zernike Fit panel.
·
Increase the camera resolution ( Camera Settings ) in case the pupil diameter is close to
the image size
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,
increased calculation errors may still occur during the Zernike Fit, especially in case of high or-
ders. For this reason, to fit higher order Zernikes (up to order 7-10), an extra spot count of
about 30% is required.
To prevent this warning
·
Check the beam that is being analyzed for proper alignment and make sure that its intens-
ity dominates the ambient light level and/or
·
Increase the pupil diameter ( Pupil Definitions panel) and/or
·
Reduce the number of Zernike orders in the Zernike Fit panel.
·
Increase the camera resolution ( Camera Settings ) in case the pupil diameter is close to
the image size
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, some visible spots at
the border of each camera image remain undetected. The pupil dimension must not be larger
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