Fast conversion factor measurement of a CCD using Images with vertical gradient
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Fast conversion factor measurement of a CCD
using Images withvertical gradient
Charge Transfer Efficiency based on
The variance of the signal in flat
Field images, gain correction
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Fast conversion factor measurement of a CCD using Images with vertical gradient
Introduction
Fast way to realize Photon Transfer CurveAppropriate to use this technique during CCD tuning
The method
Im1 + Im2
For each line i of Im: The mean is calculated (Si)
2Im =
Is = Im1 - Im2For each line i of Is: The variance is calculated (σi
2)
Each (Si, σi2) pair is plotted
Im1 and Im2, two TDI images
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Results.
1. Preliminary work. Mask cosmetic defects.2. Flat Field of TDI images.3. Weighted least square method.4. Automatic detection of the beginning of the non
linearity regime.5. User friendly program.
Future work.
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Charge Transfer Efficiency based on the variance of the signal in flat Field images, gain correction.
Change in Variance in Flat Field (CVF) Method.
Is = Im1 - Im2For each line (column) i of Is: The variance is calculated (σi
2)Each (i, σi
2) pairis plotted
Results
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How can I correlate previous plots to the CTE?
Expression of the variance affected by the CTE (a = 1- b)
Conclusion
The best fit line of the previous plot:
Gives us the Charge Transfer Efficiency:
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Results, Simulated data.
Results, Real data.Conclusion
Results promising.• Mask cosmetic defects• Work in 2d instead of 1d• Direct comparison CVF versus
ESO Fe55 setup• User friendly program