Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
Collapse
Brand Logo

ModalAI Forum

  1. ModalAI Support Forum
  2. Ask your questions right here!
  3. Stereo Cameras are highly inaccurate

Stereo Cameras are highly inaccurate

Scheduled Pinned Locked Moved Ask your questions right here!
11 Posts 3 Posters 1.6k Views 2 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • Daniel RyuD Offline
    Daniel RyuD Offline
    Daniel Ryu
    Regular
    wrote on last edited by
    #2

    Clarifying notes:

    Same problem seen on another m500 drone.
    Calibration card used has a spacing of 98.8 mm between the center of each circles (acircles card). 4x11

    1 Reply Last reply
    0
    • Daniel RyuD Offline
      Daniel RyuD Offline
      Daniel Ryu
      Regular
      wrote on last edited by
      #3

      Image from iOS (2).jpg

      1 Reply Last reply
      0
      • Chad SweetC Offline
        Chad SweetC Offline
        Chad Sweet
        ModalAI Team
        wrote on last edited by
        #4

        you need to get the calibration target professionally printed. All of those inaccuracies in what you have put together are going to create issues with calibration. Any office printing place can print a card like that from PDF on stiff backing. I don't think what you have is going to work that well

        Daniel RyuD 2 Replies Last reply
        0
        • Chad SweetC Chad Sweet

          you need to get the calibration target professionally printed. All of those inaccuracies in what you have put together are going to create issues with calibration. Any office printing place can print a card like that from PDF on stiff backing. I don't think what you have is going to work that well

          Daniel RyuD Offline
          Daniel RyuD Offline
          Daniel Ryu
          Regular
          wrote on last edited by
          #5

          @Chad-Sweet I'll try again with a card professionally printed card and get back to you

          1 Reply Last reply
          0
          • Chad SweetC Chad Sweet

            you need to get the calibration target professionally printed. All of those inaccuracies in what you have put together are going to create issues with calibration. Any office printing place can print a card like that from PDF on stiff backing. I don't think what you have is going to work that well

            Daniel RyuD Offline
            Daniel RyuD Offline
            Daniel Ryu
            Regular
            wrote on last edited by Daniel Ryu
            #6

            @Chad-Sweet Here are the results with the pictured calibration board we used (spacing 117.5 mm center to center). As you can see, we still have a detection at 0 degrees at 0.2 meters, when there should be nothing at all.

            Screenshot from 2021-09-03 13-22-39.png

            Screenshot from 2021-09-03 13-24-55.png
            Image from iOS.jpg

            1 Reply Last reply
            0
            • Daniel RyuD Offline
              Daniel RyuD Offline
              Daniel Ryu
              Regular
              wrote on last edited by
              #7

              Note: Every other angle appears to be somewhat accurate, everything except the measurements at 0 degrees

              1 Reply Last reply
              0
              • J Offline
                J Offline
                jaredjohansen
                Regular
                wrote on last edited by
                #8

                An update on our efforts in this regard.

                We have now attempted to calibrate 4 different VOXLs. In one case, we calibrated the VOXL board twice (with similar results).

                We have tried with three different circles grids (two of which were professionally printed).

                In all cases, at the zero degree angle, there is an obstacle constantly detected at 0.2 meters. We do not know why this is. We presume this is a problem. Is it? If not, why?

                In three of the four cases, the detections at all other angles are inaccurate. In these three cases, in general, they "sense" when an obstacle is within their bin range, but this is not always the cause: sometimes miss detecting obstacles. In the three cases where the detection are inaccurate, they can be off by several meters. We expect that autonomous navigation that relies on the output of these bins would cause problems. Do you have any additional guidance on how to get this working more accurately?

                1 Reply Last reply
                0
                • Chad SweetC Offline
                  Chad SweetC Offline
                  Chad Sweet
                  ModalAI Team
                  wrote on last edited by
                  #9

                  This looks like it could be a bug, we're looking into it. In the meantime you can just comment out using the center bin

                  1 Reply Last reply
                  0
                  • Chad SweetC Offline
                    Chad SweetC Offline
                    Chad Sweet
                    ModalAI Team
                    wrote on last edited by
                    #10

                    A potential fix for this has been pushed to the dev branch

                    change

                    Daniel RyuD 1 Reply Last reply
                    0
                    • Chad SweetC Chad Sweet

                      A potential fix for this has been pushed to the dev branch

                      change

                      Daniel RyuD Offline
                      Daniel RyuD Offline
                      Daniel Ryu
                      Regular
                      wrote on last edited by
                      #11

                      @Chad-Sweet The fix in the dev branch successfully populates the 0th degree bin for obstacle detection. We are now able to run VOA mostly successfully, with one observable bug with the voxl-camera-server/voxl-dfs-server. Please see this post for details: https://forum.modalai.com/topic/450/intermittent-crashing-of-voxl-camera-server-during-voa-testing?_=1631837674205

                      1 Reply Last reply
                      0

                      Hello! It looks like you're interested in this conversation, but you don't have an account yet.

                      Getting fed up of having to scroll through the same posts each visit? When you register for an account, you'll always come back to exactly where you were before, and choose to be notified of new replies (either via email, or push notification). You'll also be able to save bookmarks and upvote posts to show your appreciation to other community members.

                      With your input, this post could be even better 💗

                      Register Login
                      Reply
                      • Reply as topic
                      Log in to reply
                      • Oldest to Newest
                      • Newest to Oldest
                      • Most Votes


                      ModalAI
                      Categories Recent Tags ModalAI.com Docs
                      © 2026 ModalAI® · Accelerating autonomy for smaller, smarter, safer drones · Powered by NodeBB
                      • Login

                      • Login or register to search.
                      • First post
                        Last post
                      0
                      • Categories
                      • Recent
                      • Tags
                      • Popular
                      • Users
                      • Groups