We’ve been experiencing some questionable results when processing the data taken with our setup. We’re currently using a DJI M600 w/ the Zenmuse X5R coupled with the 15mm Lumix G lens. 9 GCP’s were placed on the 10 acre site, at a spacing of roughly 400 ft. Ground control is reliable and placed by our in-house surveyors so we can rule that out as a variable. We’re using the MapPilot app to control overlap and flight lines, and feel that this app is pretty reliable. It also controls image attributes such as shutter speed and exposure. There’s not a terribly pragmatic way to maintain full control over the camera when flying a grid.
During processing, step 1 was run on Full Image size. Ground control was tagged in all available images in the Ray Cloud editor. Camera parameters were optimized. The project was then reoptimized and the quality report yielded all green.
In this smaller dataset of roughly 250 images, the calculated positions of the ground control are very tight (mean RMS of 0.01), but the Z value of checkpoints used can vary as much as 0.7 or 0.8ft (some as close as 20 feet from a GCP). That sort of tolerance won’t work for the standards we’re trying to achieve. It seems as though the processing yielded a false positive. This is similar to the 3+ times we’ve rerun this batch of images.
My colleague and I believe the root cause is the camera, but it’s hard to say.
If anyone uses this same camera, or has faced a similar issue with the Zenmuse line of cameras, I’d be very curious to hear your experience with the entirety of the process. I’m open to advice on image acquisition. Also curious to hear if I may be missing a step in processing.