Issues on undistiortion module

[SternSu]

Hi, I am using DAVIS346 mono with DV-GUI on windows 10. I followed the instructions to use the calibration module and obtained the calibration results. After I used the calibration results to undistort the events with undistiortion module, I observed many black circles in the output events like the figure 1 shows. Could you tell me what the reason is? I also attach the structure of modules in figure 2.

[Luca Longinotti]

You're seeing the radial lens distortion. This is normal, when remapping event coordinates, only integers can be used, so there are pixels that never get events remapped to them.

On the frame output you don't see this because the frames do interpolate the missing data for these pixels, which cannot be done the same way for events.

-- 

Luca Longinotti (llongi)

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

[SternSu]

When I did not use the undistortion module, the output events are normal.

[SternSu]

Thank you for your reply. Does it mean that, when we are using events from a real camera, we can only use this kind of undistorted events as input to the next step algorithms (optical flow estimation, etc.)? 

[Tobi Delbruck (INI)]

It's probably better to compute flow on the sensor plane and then
undistort the flow results.

[SternSu]

Thank you for your advice, I will give it a try.