Timestamp mapping visualization

[Santo Santhosh]

Hey I have been working on the Davis 240C for the past couple of days, my aim is to send triggers from a Teensy board and sync the timer from the board and the timer from the camera at postprocessing. So I store all of the data by recording an aedat4 file which stores everything except imu data from the camera using the dv-processing library. 

From the prerecorded file, I get the timestamps for the following, events, frames and triggers. When I map these out onto a plot the visualization is throwing me off. I don't know if I am doing something wrong here, the plot is basically a delta time vs time graph. Where the y axis has the difference between consecutive timestamps, and x axis is the relative global time from the camera. The final aim is to also add the timer data from the board and see if there is any differences. Let me know if you need anything further from my side.
Thanks

[Luca Longinotti]

Hello,

the events look fine, so I assume your question is about frames and triggers.

The frame timestamp deltas increase over time probably due to auto-exposure, it adjusts to darker conditions and extends the exposure time, which slows down the frame rate and thus increases the time between consecutive frames, and stabilizes after a bit.

For the triggers, the fact the curve looks very much like the frame one is a possible clue: there are different types of triggers, you need to check the 'type' field of triggers and only get the ones coming from the external detector, which are probably the nice line in your graph.

There's also a set of triggers that represent frame capture and exposure start/end times, and those are contributing to the curve part that follows the frames. Just filter those out.

Hope this helps, have a great day!

-- 

Luca Longinotti (llongi)

Senior Software Engineer
iniVation AG - https://inivation.com/
A SynSense Group company