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Audine with Ethernaude = non-linearity measurements with TDI method

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I used the TDI method to try to confirm the non-linearity measured with the radiometric method. I was careful to thermally stabilize the Audine camera, and to use a LED that was illuminating uniformly the CCD sensor. I started a TDI acquisition, and after 1 or 2 seconds I switched on the illuminating LED.

I am not completely sure about the measurements because with this method, the LED was just switched on and thus not thermally stable. It could vary a little bit and contribute to non-linearity. A better setup would use a shutter. Nevertheless, the results seem consistent with those of the radiometric method.

As for the radiometric method, a time offset has to be found to get the final non-linearity curves. This offset comes from the absence of synchronisation between the TDI read-out times and the instant when the LED was switched on.

First measurement:

Two TDI delays have been used (100 ms and 250 ms).
The Audine camera was well stabilised, but I did not check the drift in temperature so there might be a residual effect.



Second measurement (Audine with better temperature stability):

The same two TDI delays were used.
This time I carefully checked the temperature drift = from -10.5 to -10.2 deg during 32 min of measurement.