Orientation data (yaw, pitch, roll) on geotagging

jstroup1986 · January 26, 2024, 12:51pm

I’ve been doing a deep dive into WebODM for photogrammetry processing.

I’ve learned that WebODM has the ability to convert yaw, pitch, roll data to omega, phi, kappa values for image orientation.

github.com

OpenDroneMap/ODM/blob/ae50133886d5e4417d5b684bd2d6cffbabb209f4/opendm/photo.py#L864


      
          
          def has_speed(self):
              return self.speed_x is not None and \
                      self.speed_y is not None and \
                      self.speed_z is not None
          
          def has_geo(self):
              return self.latitude is not None and \
                  self.longitude is not None
          
          def compute_opk(self):
              if self.has_ypr() and self.has_geo():
                  y, p, r = math.radians(self.yaw), math.radians(self.pitch), math.radians(self.roll)
          
                  # Ref: New Calibration and Computing Method for Direct 
                  # Georeferencing of Image and Scanner Data Using the 
                  # Position and Angular Data of an Hybrid Inertial Navigation System 
                  # by Manfred Bäumker
          
                  # YPR rotation matrix
                  cnb = np.array([[ math.cos(y) * math.cos(p), math.cos(y) * math.sin(p) * math.sin(r) - math.sin(y) * math.cos(r), math.cos(y) * math.sin(p) * math.cos(r) + math.sin(y) * math.sin(r)],

I’ve never found a EXIF viewer that displays either yaw, pitch, roll - or omega, phi, kappa in an image EXIF.

I do know that Pix4D has the ability to convert orientation from a DJI drone’s images to omega, phi, kappa values. It does not do so for Mission Planner geotagged images - neither will it do so when the geotag data is taken from the Mission Planner geotag CSV geolocation file.

Is it possible to confirm if the Mission Planner geotag routine does add yaw, pitch, roll data to each image - and is there a viewer that allows seeing this data?

There is a small wrinkle in this. When camera’s are attached with a fixed NADIR mount, the pitch data would be of the aircraft - hence 90 degrees off for the image.

I’m trying to get the WebODM dev’s to help in my understanding of what’s happening on this matter.

The thread I’ve created is here:

It would be really helpful to get some clarification on what Mission Planner’s geotag routine does with the orientation data. I know it’s available in the CSV geolocation file. But I don’t know if any such values are actually added to the image EXIF data.

If anyone could clarify what’s happening here, I would greatly appreciate it.

Thank you!

jstroup1986 · January 26, 2024, 11:39pm

Digging into this a bit further, I’ve learned that WebODM has the option of using a text file with geotag and camera orientation values for processing the location and position data. WebODM refers to this file as a geolocation file.

The format of this WebODM file is very similar to the text and CSV files that the Mission Planner geotag routine produces.

I might suggest that Mission Planner have an option to generate a file that meets this specification - but its such a simple change, perhaps its best to let the operator make the necessary modifications to the file.

Letting the operator do this would allow changing some of the values - for example, where a camera is fixed in the NADIR position, the pitch value would need to be changed 90 degrees from the drone’s pitch.

Processing Mavic 2 Pro images with WebODM - with and without the camera orientation values, I find that with the camera orientation values the point-cloud with the camera orientation values has about 20% more points. This is valuable.

Here’s an excerpt from the WebODM manual that explains the format of it’s geolocation files used for this data.

Eosbandi · January 27, 2024, 7:18pm

Mission planner assumes a stabilized camera, and adds only lat/lng/alt tags to the geotagged images.

jstroup1986 · January 27, 2024, 8:06pm

Attached are two location.txt files produced by Mission Planner when doing the geolocation process.

Note both files have yaw, pitch and roll entries.

fixed mounted camera - no gimbal - location.txt (51.6 KB)

camera mounted on gimbal - location.txt (28.7 KB)

Eosbandi · January 27, 2024, 8:12pm

Yes, but they not put into exif by the tool in MP.

jstroup1986 · January 27, 2024, 8:18pm

Yes, exactly - which is the point of my post.

WebODM supports a “geolocation file” that has almost exactly the same format as the Mission Planner’s location.txt file.

I’m thinking that some simple user procedures can be written that makes it easy to convert the location.txt file into a WebODM geolocation file.

It would be really wonderful if Mission Planner had the option to create such a file directly - but that’s probably too much to ask.