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foobarbecue / surfptz

Simple robotic camera system for tracking surfing
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magnetometer calibration #2

Closed foobarbecue closed 2 years ago

foobarbecue commented 2 years ago

Tried to do mag cal with the witmotion minimu software. Software made it seem like it worked. Then I tried setting z-axis zero and it was fine for a bit but then swung 90 deg in a few secs when the IMU was stationary. It's too confusing trying to figure out what their sensor fusion is so I think I want to use the raw mag data and calibrate it myself. Using a modified version of https://learn.adafruit.com/adafruit-sensorlab-magnetometer-calibration/magnetic-calibration-with-jupyter ,

before: image

after: image

Not great. I think I will use the precision approach from http://juddzone.com/ALGORITHMS/least_squares_precision_3D_ellipsoid.html

Note that this is all done with the IMU/mag mounted on the camera.

foobarbecue commented 2 years ago

In the end, the witmotion calibration (Ellipse fitting) worked pretty well, following the manual. I think I messed things up by trying to set the Z-axis zero -- that's designed for 6-DOF mode and seems to cause weird behavior in 9-DOF mode.