DJI drone georeference video - using altitude recorded by laser?

PIX4Dmapper
1

Hi,

I am new to Pix4D and a rookie in the field of georeferencing and GIS, and I have some questions about the possibilities of the PIX4D software:

We are using a DJI phantom pro 4 V2 drone and fly it over sea, recording video footage which we want to use for photogrammetry. To have higher accuracy of altitude, we use a laser that records the altitude and will not be using the altitude recorded by the drone.

My aim is to georeference snapshots from the videos and correct for the gimball angle and altitude (to be able to get accurate measurements of any objects that were filmed), using the known altitude and known gimbal settings.

My questions are:

  • Can I use Pix4D mapper to convert the images to georeferenced files (i.e. TIFF) and use the gimbal settings (etc) from the flight log data of my drone to correct for the camera angles deviating from zero?
  • If this is possible; Can I use the altitude recorded by our laser, or can I only work with the altitude recorded by our drone?

Thanks!
Anne

3

Hello Anne,
The problem is that the video frames will not be georeferenced and PIX4Dmapper does not have the ability to amend the exif data with the correct georeferenced location. It is possible that some third party software may have the ability to perform this function but PIX4Dmapper does not. Despite the lack of a georeferenced location you can amend the exif by clicking on the To File button.

2021-08-23_16-40-02
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From here you can amend the data and the upload it by clicking on the From File.

4

Hi Mike,
Thank you so much for your reply. I was planning on making snapshot images from the video instead of using the video as it is. Would it be possible with the snapshots?
Do you by any chance know of any other software that can perform the “georeferencing” process incl. correcting for the angles etc. ? Or would I have to do this manually in a GIS software by calculating the coords of each corner?
Thanks
Anne

5

Hi Anne,
Yes, PIX4Dmapper can process videos for photogrammetry. The link below describes the process. But like I mentioned earlier it will not be georeferenced and can cause other problems. It will be much simpler if you can fly a traditional grid mission since all of the required data will be recorded in the exif data. Unfortunately I don’t have any recommendations for third-party software since needing to manipulate the exif data is not very common.