VOXL2 VIO Losing features

Jetson Nano

Hey, @James-Strawson @Eric @Alex-Kushleyev

I'm using a VOXL2 on a custom airframe build with external FC. For VIO, I'm relying on a ov7251 tracking camera.

In the QVIO server, whenever I initialise the server, features are detected and the overlay displays 100%. But when the drone takes-off in stabilized mode, the features displayed in the overlay starts randomly blinking and reappearing.
During flight, when the drone is shifted to position mode also, the same cycle of features blinking and reappearing repeats with the overlay displaying 1% or -1%, making the drone drift, losing position.
In the concurrent flights, on ground despite reinitialising the server services, the QVIO server overlay shows -1% or 1% due this effect.

Also, I have been testing the system with earlier SDKs (ie. 0.9.5, 1.0.0, 1.1.0). But I have been the observing the above mode of losing features in later SDKs only( ie. 1.2.0, 1.3.0).

Sharing a drive link, where I have uploaded the screencapture of the same issue.

Screen recordings

Jetson Nano

Could you pl look into @James-Strawson @Eric-Katzfey @Alex-Kushleyev @Chad-Sweet ?

Alex Kushleyev

@Jetson-Nano , usually if you see VIO "blow up" right after you start moving, it means incorrect extrinsic parameters (transform between the VIO camera and VIO IMU).

It is possible that after updating the SDK, you did not set the extrinsics correctly. Are you using a standard configuration (orientation of the tracking camera with respect to VOXL2 board)? This is definitely something to verify first.

Also, one question: after you just start the QVIO server, do you see features jumping around? or they only start jumping around after there is some motion. It was not clear from the videos whether they were recorded right after qvio server start or at some point later (after motion).

Alex

Jetson Nano

@Alex-Kushleyev It is not standard configuration, I am using it with a different frame. I'll verify the extrinsics and try again.

When I restart qvio server the points are fine, it starts jumping only if there is some motion.

Alex Kushleyev

@Jetson-Nano , thanks for confirming. Yes, that is a sign of incorrect IMU to camera transform (tracking camera extrinsics).