Poor quality of stereo-camera calibration

  • Hi,
    I am trying to calibrate stereo vision on two different systems. The first system is the Qualcomm Flight Pro Development Kit, while the second is the VOXL Flight equipped with an M0015-1 VOXL stereo sensor. The first system passes the calibration process quickly with reasonable re-projection errors. However, the re-projection errors of the second system are very high (~0.45 for both intrinsic and extrinsic) and the disparity map is very poor. Why are the errors on M0015-1 so high? It seems that those are almost identical cameras. The calibration target (8x6 40mm Checkerboard) and lighting conditions are the same.

  • Dev Team

    I recommend viewing the images through Portal to check the focus of the stereo sensors as it may need to be adjusted. It is possible the focus may have changed due to handling and/or shipping. Refocusing can improve your reprojection error.
    To adjust the focus, a 6mm wrench fits perfectly on the flat edges of the lens. If needed, you can use some pliers/forceps/something similar to grab hold of the outer edges of the lens, just use extreme caution to not allow the jaws to slip off and scratch the lens. Pay more attention to the focus in the center of the image as sometimes there is blur around the outer edges of the image.
    Also worth mentioning is that the lenses might be dirty (fingerprints, dust, etc) . They can be gently cleaned with a microfiber cloth or similar.

  • @VictorT said in Poor quality of stereo-camera calibration:

    Qualcomm Flight Pro Development Kit

    @Dobry-Kolacz thank you for the quick response,
    The cameras are clean and focused. The M0015-1 cameras, however, have greater distortion near the edges than Qualcomm Flight Pro Development Kit cameras.

  • Dev Team

    Were you able to successfully calibrate after focusing/cleaning? The M0015-1 sensors should have no issues calibrating after they are properly focused as long as there are no scratches in the lens. Are they mounted in a VOXL Flight Deck?

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