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

ModalAI Forum

  1. ModalAI Support Forum
  2. FAQs
  3. Error on running dfs_server. Cannot get Point Cloud

Error on running dfs_server. Cannot get Point Cloud

Scheduled Pinned Locked Moved Unsolved FAQs
2 Posts 2 Posters 1.1k Views 1 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.
  • Prasad AntervediP Offline
    Prasad AntervediP Offline
    Prasad Antervedi
    wrote on last edited by
    #1

    Hi!
    I want to get the point cloud from the stereo imagery using the voxl-dfs-server. I have calibrated the stereo camera using the instructions given here. The calibration procedure was successful and it generated the left.yaml, right.yaml and calibration_stereo.xml files. However, it did not generate the opencv_stereo_extrinsics.yml and opencv_stereo_intrinsics.yml files. I could not find anywhere on the docs any instructions to generate these files. So I had to write them myself taking information from ost.txt. Here are the two files that I wrote:

    1. opencv_stereo_extrinsics.yml
    %YAML:1.0
    R1: !!opencv-matrix
       rows: 3
       cols: 3
       dt: d
       data: [ 0.999731, -0.005262, -0.022599,
                0.005377, 0.999973, 0.005039,
                0.022572, -0.005159, 0.999732]
    P1: !!opencv-matrix
       rows: 3
       cols: 4
       dt: d
       data: [527.372271, 0.000000, 331.544373, 0.000000,
                0.000000, 527.372271, 240.925325, 0.000000,
                0.000000, 0.000000, 1.000000, 0.000000]
    R2: !!opencv-matrix
       rows: 3
       cols: 3
       dt: d
       data: [0.998424, 0.024289, -0.050596,
            -0.024547, 0.999689, -0.004480,
            0.050471, 0.005715, 0.998709]
    P2: !!opencv-matrix
       rows: 3
       cols: 4
       dt: d
       data: [527.372271, 0.000000, 331.544373, -42.405281,
            0.000000, 527.372271, 240.925325, 0.000000,
            0.000000, 0.000000, 1.000000, 0.000000]
    
    
    1. opencv_stereo_intrinsics.yml
    M1: !!opencv-matrix
       rows: 3
       cols: 3
       dt: d
       data: [488.682800, 0.000000, 321.505138,
            0.000000, 489.299446, 232.298091,
            0.000000, 0.000000, 1.000000]
    D1: !!opencv-matrix
       rows: 1
       cols: 5
       dt: d
       data: [-0.171999, 0.074949, 0.001013, -0.001734, 0.000000]
    M2: !!opencv-matrix
       rows: 3
       cols: 3
       dt: d
       data: [ 500.025405, 0.000000, 290.363517,
                0.000000, 500.227973, 248.074606,
                0.000000, 0.000000, 1.000000]
    D2: !!opencv-matrix
       rows: 1
       cols: 5
       dt: d
       data: [-0.194946, 0.140224, 0.001638, 0.000149, 0.000000]
    
    

    Then I pushed these files to the VOXL using ./push_stereo_cal_to_voxl.sh
    However, when I run the voxl-dfs-server on the VOXL I get the following output Screenshot from 2021-10-04 15-07-53.png
    I am suspicious of my .yml files that I generated. Do you have any working .yml files that I can use as template and change values for my system.
    Please let me know how can I debug this and get the point cloud from the stereo imagery with dfs-server.
    Output of voxl-version FYI: Screenshot from 2021-10-04 15-11-45.png

    Please let me know if any other information is needed. I'd appreciate any insight into solving this.

    Thanks
    Prasad

    1 Reply Last reply
    0
    • ? Offline
      ? Offline
      A Former User
      wrote on last edited by
      #2

      Hi Prasad,

      I've seen the error that you talked about with the ungenerated once or twice and running the calibration procedure again properly generated the files.

      This is a sample stereo cal from my board (that has a few additional data fields from a soon to be released cal rework) that would serve as a good general idea of what the files should look like. The DFS algorithm is, however, very sensitive to inaccuracies and I'd strongly recommend trying to calibrate your cameras again, but if that doesn't work you can add your values to this format:

      yocto:/$ cat /data/modalai/opencv_stereo_extrinsics.yml 
      %YAML:1.0
      ---
      R: !!opencv-matrix
         rows: 3
         cols: 3
         dt: d
         data: [ 9.9965050025202740e-01, -5.6519379540328910e-04,
             2.6430245966411248e-02, 2.8842568739021546e-03,
             9.9613506820545850e-01, -8.7787282413751958e-02,
             -2.6278478041102546e-02, 8.7832832399280705e-02,
             9.9578854941426354e-01 ]
      T: !!opencv-matrix
         rows: 3
         cols: 1
         dt: d
         data: [ -7.9514399346537298e-02, -2.7245018421472277e-03,
             6.0288890076187220e-04 ]
      reprojection_error: 2.8997817600221831e-01
      calibration_time: "2021-09-30 22:52:56"
      yocto:/$ cat /data/modalai/opencv_stereo_intrinsics.yml     
      %YAML:1.0
      ---
      M1: !!opencv-matrix
         rows: 3
         cols: 3
         dt: d
         data: [ 4.9291881707143079e+02, 0., 3.0643471662712096e+02, 0.,
             4.9232152259255315e+02, 2.1697996372929907e+02, 0., 0., 1. ]
      D1: !!opencv-matrix
         rows: 5
         cols: 1
         dt: d
         data: [ -1.6984598364049669e-01, 6.0034285910162230e-02,
             -8.8644933037586781e-04, -4.1419313003228072e-04, 0. ]
      reprojection_error1: 1.9741562557305206e-01
      M2: !!opencv-matrix
         rows: 3
         cols: 3
         dt: d
         data: [ 4.9673975454370270e+02, 0., 3.1711708934220133e+02, 0.,
             4.9610254255552854e+02, 2.2876245199481119e+02, 0., 0., 1. ]
      D2: !!opencv-matrix
         rows: 5
         cols: 1
         dt: d
         data: [ -1.6758727319959599e-01, 5.4041564358266361e-02,
             -1.5695644102222835e-03, -5.8891426327232642e-04, 0. ]
      reprojection_error2: 3.1594418176162986e-01
      width: 640
      height: 480
      distortion_model: plumb_bob
      calibration_time: "2021-09-30 22:52:56"
      
      1 Reply Last reply
      0

      Reading along? Create a free ModalAI Forum account to join in.

      With an account you can reply, ask your own question, get an email when a ModalAI engineer answers, and mark the reply that solved it. Your place in each thread is saved between visits.

      Questions about VOXL, Flight Core, ESCs and ModalAI drones are answered here by the engineers who build them.

      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

      • Don't have an account? Register

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