Hi,

I acquired several weeks ago a Mavic Mini, and so far, I'm very pleased with it, taking amazing aerial pictures in Göteborg and Stockholm areas ! But taking nice panoramas is not the only reason I bought this drone. I am an engineer in Computer Vision, and I would like to use my drone for visual odometry (determining the position and orientation of the drone by analyzing a succesion of images), by developing my own machine learning algorithm.

To do this, I would like to retrieve the 3D position of my drone when taking a picture or video, as ground truth. I was a bit surprised to find only the relative altitude, but not the X and Y componants in the picture's metadata. I don't think using GPS latitude/longitude should be considered in my case, it's probably not precise enough. Same applies for speed in video. I didn't check in details the video's metadata, but it seems to be the same?

When I fly my drone, the height, the horizontal distance and the direction of the drone is displayed on the screen, my question is why these informations are not provided in metadata, and how I could retrieve them. I am fine with cartesian coordinates or polar coordinates (as it appears on the smartphone).

My second question is to know what kind of accuracy I should expect if I use the relative position of the drone ? Same question for GPS signal.

Should I wait for the release of the Mavic Mini SDK? (Which was supposed to happen in April 2020 last time I checked?)

Best,
Clément

I was a bit surprised to find only the relative altitude, but not the X and Y componants in the picture's metadata.
There's a lot more information stored in the metadata for other DJI drones (and probably even the Mini).
Try using a different viewer and see what's hidden in the XMP information and Other.
Here's one program that will dig deeper into the Metadata to show what's there:
https://www.picmeta.com/products/picture-information-extractor.htm

Labroides Posted at 7-11 17:19
I was a bit surprised to find only the relative altitude, but not the X and Y componants in the picture's metadata.
There's a lot more information stored in the metadata for other DJI drones (and probably even the Mini).
Try using a different viewer and see what's hidden in the XMP information and Other.

Hi Labroides,

Thank you for your message. I checked with picmeta as you suggested, but I did not find any interesting data. The only position I found is from GPS, but nothing in relative coordinates as displayed on the drone.

So I have raw/pitch/roll, but the distance is missing, which is very frustrating.

So I just checked one more time and I can confirm I can't find any relative position information in metadata except altitude ... Any suggestion would be appreciated

The AC only has a GPS, barometer and compass to determine position, altitude and orientation, and this info is available in the flight records together with the coordinates of the Home Point. You should have everything you need to calculate the relative position of the AC when a photo/video was taken, but it will always be dependent on GPS accuracy. There is no other magic way for the AC to know its position, relative or absolute.