GoPro -> 3D GCP -> Jagged Triangle Mesh

[jlynch]

Hi folks,

I’m working on creating an ortho/contour output from imagery I took walking with a GoPro MAX 3.0 camera. When I went through the three processing steps without applying 3D GCPs, the surface came out smooth. When I applied three 3D GCPs after the initial processing, however, it resulted in a jagged surface (see below). Is there a step I’m missing in the processing? Any thoughts would be appreciated.

Thanks!
Jackson

[Rosana_Lin]

Hi Jackson,

Welcome to the community! Happ to see you here.

Would you mind sharing the quality report with us? Menu Process > Generate Quality Report

▸ The project log file (text file): …\project_name\project_name.log

Meanwhile, I am sharing these articles on Processing images from GoPro cameras and How to calibrate a Fisheye Lens Camera. If you have already read through them, please don’t mind me.

Looking forward to the quality report.

Sincerely,
Rosana

[jlynch]

Thanks Rosana!

Here is the quality report for a project where I used my phone (pix4Dcatch) to capture images, and then used GCPs collected by survey to calibrate. I ran into the same issue on this model as the one in the orginal post. Before applying the GCPs, the tie points were showing up normally but after applying the GCPs the tie points snapped to some sort of grid that happens before the mesh in the orginal post is created.

2528804_MMP_SW_v2_report.pdf (1.5 MB)

[Rosana_Lin]

Hi Jackson,

Thank you for sharing more about your project.
Based on the quality report, the median of keypoints per image is the issue.

After cross-checking the number of ATPs per pixel, I could see there are some black dots. Black indicates that, on average, 0 ATPs have been extracted at
the pixel location. So the more black dots we have, it indicates there is a high chance the issue could be related to overlap.

Have you tried adding some MTPs and then reoptimize? If not, I recommend adding some MTPs. Menu Process > Reoptimize

Using a GoPro is quite tricky and can be very challenging. If anyone else or GoPro users have thoughts or experience with this sort of workflow feel free to provide your additional advice or experiences.
I also found this thread that increasing the overlap sometimes could greatly help with the issue.

GoPro on a pole?

Hi Nicolas, I was able to get the images to calibrate using the following Step 1 processing options.  _ Keypoint image scale = Full_ _ Matching Image Pairs = Free flight or terrestrial_ _ Calibration Method = Alternative_ _ Internal parameters optimization = All Prior_  Despite being able to calibrate there is a substantial amount of noise generated by the sky. You can use the carve annotation tool to help reduce the noise before running step 2. Also, I would recommend creating a few MTPs …

Best regards,
Rosana