Mapping with the X8 wing

Hi all,

I want to share some of the latest results I achieved with using ardupilot and my X8-wing for aerial mapping. Below you can see a picture of the X8-wing with the ardupilot and camera (canon ixus 220HS with CHDK). I started off with the  standard PID settings which worked well. Basically add some  more control to the  nav-roll P value and you are good to go.

3690969118?profile=original

An example of the flight pattern flow, along with the position of the images taken:

3690969015?profile=originalThese positions was generated with the georeference tool in Missionplanner, based on the tlog file and image information. However, as my xbee module sometimes loses some packages in its connection with the groundstation, the tlog files are not really useful as I am losing valuable sync information. That’s why I am using the inflight log files to sync with the images. One side note to those using an interval script to trigger the camera: as you are limited to the 1sec accuracy of your camera clock, it’s possible to make some serious mistakes in camera position/attitude. Below you can see an example of the roll information recorded in 10hz and averaged over an 1 sec interval, and you see what I mean.

3690969171?profile=original

Next thing I will be investigating in is in the servo triggering. Anybody using a setup with this device: http://store.diydrones.com/ProductDetails.asp?ProductCode=BR-0007-01

Then the processing. I uploaded a set  of 17 images with the synced XYZ information to dronemapper.org to generate an orthomosaic. Very user-friendly website, fast and reliable processing. After 2 hours I already had my ortho along with a DEM and point cloud.  I realize that the output is only as good as the input, which needs some improvements on shutter time speed, image sync and GCP’s , but I am already very satisfied with the results.

[EDIT: Comparison with Pix4D was removed because different input was used: hopefully I'll be able to redo the comparison with the same imagery selected as input]

3690969139?profile=original

 "Absolute" accuracy with google earth (I know, we should not use it as a reference..) is in the order of 5m

If we zoom in, you can see that linear structures were reconstructed quite successfully.

3690969028?profile=original

However, there are some problem areas in which the merging process created artefacts:

3690969202?profile=original

cheers

Dries

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  • ++ Feedback CAM

    ArduCopter: added support for simple digital pin

    https://github.com/taedla01/ardupilot/commit/e338525785b46411aec32e...

    ArduCopter: added support for simple digital pin · taedla01/ardupilot@e338525
    APM Plane, APM Copter, APM Rover source. Contribute to taedla01/ardupilot development by creating an account on GitHub.
  • Adding:

    Brian Christal replied to Dave Williams's discussion "Using AUX pins as relays for CHDK" on DIY Drones

    ------------
    Chasing the camera delay from CAM trigger message to shutter open is futile. Feedback from the camera to the autopilot is required. It's being addressed here:

    https://github.com/diydrones/ardupilot/issues/2289

    http://chdk.setepontos.com/index.php?topic=12398.0



    Brian
    ------------

  • Hello Dries,

    I'm building a model like yours.

    What is the speed of this model? Do you have problems between the trigger signal and the opening of the shutter? I use a quadricopter for mapping. Flying to 5 m / s I have delay between the trigger signal and the shutter opens. The board sends the signal to the camera but the shot is not instantaneous. I think what this can affect in a model that fly faster than 10m / s. Please any help is welcome.

    Best Regards,

    Plínio Augusto

  • Here are some additional accuracy checks and information:

    http://dronemapper.com/node/119

    Full reports are downloadable.. 

    Test Case RMSE X (m) RMSE Y (m) RMSE Z (m) CE90 (m)
    1 - Camera Tags 8.4 6.7 27.6 14
    2 - Falcon Tags 4.5 9.2 27.7 6.4
    3 - 6 GCP 0.17 0.18 1.9 0.35

  • great pic. I m waiting for your new sample.

  • Great post!

    I'm very interested in the servo triggering you've mentioned. The Bramor UAV seems to use a similar connection on their cameras. Great work on the pictures, looking forward to seeing your next samples.

    PT

  • thanks for the great post Dries!

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