Faulty defocus compensation due to slow first images #113
Description
In our setup, for whatever reason the first two images take a long time to acquire, generally 1200 and 1000 ms each.
When the first few defocus frames arrive, the calculation acquisition_time = (t_start - t0) / (i - 1) from line 301 in cred/experiment.py overestimates the real acquisition time and does not properly skip a frame until sufficiently many frames have been taken to reduce the average time.
One way to solve it could be to use a more robust estimator, like the median frame time instead of the mean.
Example
Acquisition times. Here you can see that the first two frames take a long time to acquire for whatever reason.
Time between captures. Here you can see that even though the defocus frames 10 and 20 take a long time, the frames 11 and 21 are not skipped.
