2 questions DVXplorer

[Kathy]

I have 2 questions: 

1) I used a shaker to vibrate the DVXplorer from 1 to 7 Hz.  I used Matlab to read in the IMU accelerometer data from the DVXplorer and on the FFT, it appears there is a large DC component at 1 hz which overpowers any frequency data.  Should I be able to detect a vibrational frequency of 1 hz using the accelerometer IMU data?  

2)  Is there any existing software to subtract the IMU data from camera events on a DVXplorer?  I also have a DAVIS 346 and DAVIS 240 if software exists for either of those cameras.

Thanks,

Kathy

[Tobi Delbruck (UZH-ETH)]

Hi Kathy, the first IMU integration with DVS / DAVIS was done by us and is written up in

Delbruck, T., V. Villanueva, and L. Longinotti. 2014. “Integration of Dynamic Vision Sensor with Inertial Measurement Unit for Electronically Stabilized Event-Based Vision.” In 2014 IEEE International Symposium on Circuits and Systems (ISCAS), 2636–39. ieeexplore.ieee.org. https://doi.org/10.1109/ISCAS.2014.6865714.

The implementation in jAER of Steadicam is a bit messy but I use it often in talks to demonstrate the gyro stabilization of the DVS output. I had a lot of fun with it and discovered some pretty severe nonidealities of the IMUs we chose to use (they were cheap Invensene 6 DOF smartphone-targetted IMUs).

See https://github.com/SensorsINI/jaer/blob/master/src/net/sf/jaer/eventprocessing/filter/Steadicam.java for source code. It is a standard jAER event filter so you just need to activate it and set the proper lens focal length to stabilize the output. Let me know if you want me to record a tutorial video to go with the other jAER tutorials.

Here are some videos

Tobi Delbruck. 2013. Stabilizing DVS Output with IMU Rate Gyros. http://www.youtube.com/watch?v=_twn_x94ins&feature=youtube_gdata_player.

Tobi Delbruck. 2013. DVS IMU Stabilization Examples Outdoors and Cross Target. https://youtu.be/SimREW_Mu7A.

I never found a use for the accelerometer output so far.

Good luck, Tobi

[Kathy]

Thanks for the information.  I have some data from the DVXplorer (events) that I would like to post-process to remove movement.  Will your code read aedat4 files for post processing?

[Tobi Delbruck (INI)]

No jAER doesn't process that format unfortunately. I don't know what you
mean by "movement'. If you mean camera rotation, then the gyro
stabilizization can remove it. But if the camera is moving around in
space you cannot simply use the IMU data without knowing the scene depth
structure, because the motion parallax depends on distance of the scene
from the camera.

[Kathy]

Yes, I would like to post process an aedat4 file to remove camera movement.  The camera is moving but it is pointed at a stationary pattern located on a wall.