Help with Distorted Orthomosaic Issue

[AerialGlobeSSE]

Hello,

Like I have done many times before am attempting to construct an Orthomosaic but I am looking for help trying to understand why when I get to the final step, the “Build Orthomoasic” tool does run successfully and the output is placed in the correct location, but it is badly distorted.

Approx 1020 images in the dataset were fully aligned. Orthomosaic and all previous steps were built off the mesh, and all the previous steps up until this point looked good including a tiled model ( with textures).
I can provide more details for the different parameters I used to build the mesh/ortho, but thought I would start with this general question if someone has run into  this before.  See attached photos of Tiled Model ( Undistorted) and Orthomosaic (Distorted) were taken from the same location in the dataset.

(This dataset was collected with a GoPro 11 Camera mounted to a vehicle)
Let me know if you have any other questions.

Thanks!

[AerialGlobeSSE]

Here are zoomed in screenshots where you can see the distortion more clearly.

[vineg]

Hi!

Orthomosaic is generated using top-down view by default with Z axis is up. You have Y axis pointing up. And you likely see the orthomosaic generated from a side.

You can try to generate orthomosaic in Planar Projection either in Front XZ or Back XZ Projection plane.

This problem may happen due to all photos being shot in one line and thus there is not enough reference data to estimate the vertical axis.

[Alexey Pasumansky]

Hello AerialGlobeSSE,

What options you are using in Build Orthomosaic dialog and specifically - how do you select the projection plane?

Can you share the screenshot of Build Orthomosaic dialog with the parameters that you are using and also the PDF report exported from the project?

As vineg has mentioned, seems that you are not using geographic projection option, which should generate the top down orthomosaic. Probably you have accidentally selected Current View option or one of the side views for the projection plane definition.

[AerialGlobeSSE]

Thank you for your assistance vineg and Alexey.

The orthomosaic I originally posted about was made with Projection Type: Geographic - "WGS84 (EPSG::4326)".

 I was able to try your suggestion vineg and when I tried processing with Projection Type: "Planar Tox XY"  The Orthomosaic was created without distortion!   It looks great and lines up well.  Thank you for the suggestion. 

I do wonder why this happened however to better understand because I never had this situation arise.

I wonder if it has anything to do with the fact that these images were extracted as stills from a video?

(In the process it stripped the GPS location so then I georeferenced the model with control points and exported the imagery (with GPS) and then re-ran it back through the orthomosaic creation process to create this product.)

Thanks again for any more comments and you help ~
Cheers!