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    VOA outputting zeros as distances

    VOXL Flight Deck
    voa stereo cameras dfs disparity voxl-vision-px4
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    • Chad SweetC
      Chad Sweet ModalAI Team
      last edited by

      Can you please log and share some data using voxl-logger?

      The command to log stereo and disparity is:

      voxl-logger --cam stereo --cam dfs_disparity
      

      That would help diagnose the issue

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      • ?
        A Former User
        last edited by

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        • U
          Uros @Chad Sweet
          last edited by

          @Chad-Sweet
          Hello Chad and sorry for the delayed response. We uploaded the outputs of the logger. They can be found on this link. We tried the same stereo camera pair on two different boards and we still have the same problem.

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          • Chad SweetC
            Chad Sweet ModalAI Team
            last edited by

            At a quick glance, the left and right image do not look co-planar and aligned vertically. It's a little tough to tell though as maybe your UAV is slanted? I would expect the left and right images to just look like subtle shifts directly left or right from each other.

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            • U
              Uros @Chad Sweet
              last edited by

              @Chad-Sweet
              Yes, we noticed that as well, but this is the way the cameras are mounted on the flight deck so we thought the difference is small enough. The uploaded data is from a voxl flight deck with stereo cameras that were not touched, not from the setup where we replaced one of the cameras, sorry for the confusion. Can you recommend a way to level the cameras inside the flight deck or can this misalignment somehow be fixed through calibration maybe?

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              • Chad SweetC
                Chad Sweet ModalAI Team
                last edited by

                OK, the flight deck should be fine as they are all calibrated and tested prior to shipping.

                Have you tried recalibrating in case the image sensors were jostled in some way?

                There is a good video tutorial here: https://docs.modalai.com/calibrate-cameras/#stereo-calibration-process

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                • Dobry KolaczD
                  Dobry Kolacz ModalAI Team
                  last edited by

                  Would you mind sending a photo of what your flight deck front plate looks like? I would like to see how the stereo cameras look/are mounted. The differences between your right and left stereo cameras seem a bit uncharacteristic for a VOXL flight deck (which is weird because you are saying those photos are coming from your setup before you replaced the stereo camera).

                  The other thing I noticed in the photos you provided was that the right stereo camera was slightly less in focus than the left stereo camera. I have the most success calibrating cameras when their focus is more closely matched. I look at the center of the image to gauge focal clarity as there are some stereo cameras that have some slight blurring at the edges of the image which can be misleading when adjusting focus.

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                  • U
                    Uros
                    last edited by

                    @Chad-Sweet Yes, we calibrated right before we ran the voxl-logger to get the data. We followed those instructions and the calibration was a success.
                    @Dobry-Kolacz Here are the photos of the front plate. We also tried to focus based on the center of the image, since there was always some blur towards the edges. Is it not focused enough?
                    voxl_front_plate1.jpg
                    voxl_front_plate2.jpg

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                    • Dobry KolaczD
                      Dobry Kolacz ModalAI Team
                      last edited by

                      My apologies for the delay in response,
                      So just to be clear, the images you provided are from the setup where VOA was working? The offset is odd, but the flight decks are calibrated and ready to go before they ship out so I'm wondering if that setup had any issues before the stereo camera was replaced.
                      The flight deck doesn't have any obvious defects from the photos you provided (the mounting screws seem to be tight, the front plate seems to be straight, and from what I can tell the stereo cameras are fully secured.
                      Judging on your photos, I would say that the right camera could definitely be a bit more in focus (the left camera seems to be perfectly in focus). It's easiest to tell based on your voxl1-log images.
                      Though I don't think this is necessarily contributing to your issues, it is worth mentioning that sometimes the lenses benefit from being cleaned with a clean q-tip or a microfiber cloth.

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                      • Dobry KolaczD
                        Dobry Kolacz ModalAI Team
                        last edited by

                        @Uros
                        .
                        .

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