a few questions about jaer/davis346red

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Liza Leon

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Jul 17, 2019, 3:44:58 PM7/17/19
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Hello!

I have some questions about jaer and davis346.

1) when I use jaer for 5 min or more, it is difficult to close it , it freezes and stops responding. every time I have to close it from task manager. it happens also when I want to open my last recorded video or start a new one. What should I do?

2)When I am playing my video only with events, I can see  what is behind of a moving object. it happens very quickly, but it is possible to see clearly static background. it is not a problem, I am just curious why it happens. 

3) Where can I find more information about bias configuration for DAVIS346red? I need to acquire datasets in low light. But it gives lots of noises. Filters do not help. 

Thank you!


Tobi Delbruck (INI)

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Jul 25, 2019, 7:49:50 PM7/25/19
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Sorry for delayed response; we were busy at Telluride Neuromorphic
Workshop which just concluded last Friday.

> 1) when I use jaer for 5 min or more, it is difficult to close it , it
> freezes and stops responding. every time I have to close it from task
> manager. it happens also when I want to open my last recorded video or
> start a new one. What should I do?

I have not seen freezing problem after sustained use. We routinely run
jAER for hours at a time with no problem. However it might be there is
some memory leak or some issue with Davis346Red (we only have older
Davis346Blue). Please provide more information about OS, Java version,
etc.  You can run from netbeans and send the end of the console log.
Another thing to try is to profile the project to see if there are
memory leaks.

> 2)When I am playing my video only with events, I can see  what is
> behind of a moving object. it happens very quickly, but it is possible
> to see clearly static background. it is not a problem, I am just
> curious why it happens.


You're seeing the afterimage.  Think about what happens; the DVS pixel
reports log intensity changes.  You can get a kind of exposure by
exposing the scene by taking away a gray card in front of the camera.

> 3) Where can I find more information about bias configuration for
> DAVIS346red? I need to acquire datasets in low light. But it gives
> lots of noises. Filters do not help.


Did you watch the video that is part of series
https://www.youtube.com/playlist?list=PLVtZ8f-q0U5hD9KOM4OZ1lixhwupj9uOm,
in particular Bias control at https://youtu.be/xKv-RZXcCHo
Note that since I made this video, the bias controls in jAER have been
improved so that the *estimated* ON and OFF threshold values in log
intensity change (and percent change) are computed for you; also, the
user friendly slider controls now also control both fine and coarse
values of the on-chip bias current generators.

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