Hi,
I am recently using a DJI phantom 4 v2 pro and I find it not possible to fetch the camera extrinsics of each image.
Since litchi can make the drone follow a specific path, I wonder if it can fetch and store the camera extrinsics?
To be more specific, I want to know the euler angles of the camera, or at least that of the drone (if they are separated).
Thanks
No, euler angles of the camera are not stored. However, the aircraft yaw and gimbal pitch angle are stored in the EXIF data. For example:
[XMP] FlightPitchDegree : +0.20
[XMP] FlightRollDegree : -1.50
[XMP] FlightYawDegree : -159.00
[XMP] GimbalPitchDegree : -89.90
[XMP] GimbalRollDegree : +0.00
[XMP] GimbalYawDegree : -163.20
Use a good EXIF viewer to access these values.
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Thank you for your reply.
That seems like a good starting point; can I interpret it in this way: flight degrees + gimbal degrees is a rough estimation of cam degrees.
Additionally, are these values stored in the metadata of each image (i.e., phantom 4 v2 pro will give .srt files, so I know gps for each image, but not for any angles)
I have found the one needs to use “FlightYawDegeee” and “GimbalPitchDegree” (coupled with the GPS coordinates) recreate the same view as in the photo.
Yes, they are imbedded in each image.
Thank you for your reply.
I do see pitch&yaw&roll of gimbal and flight in the image, nice.
This makes a lot of sense. May I know
- how is the drone coordinate system defined, is it North(x) East(y) Down(z)?
- for gimbal, are the axises defined in world NED, or are they relative to the drone coords system? From your observation, it seems that gimbal should be relative to drone coords.
I don’t see any XYZ coordinate system referenced in the EXIF data. The drone’s position is given using GPS coordinates.
The Yaw is measured in clockwise degrees from north. Gimbal Pitch is measured in degrees from horizontal (0=horizontal, -90=straight down).