I'm running into difficulties stitching large corn fields from aerial imagery, as shown here:
https://www.dropbox.com/s/fazxwnvjxwqvwun/Screenshot%202014-10-03%2012.35.30.png?dl=0Photoscan doesn't seem to be able to align the photos in the center of the field (see
https://www.dropbox.com/s/oaw9qdza4l646ya/Screenshot%202014-10-03%2012.36.19.png?dl=0), and the parts it does align are done so poorly (e.g. broken / non-straight corn rows), so I was hoping I could get some advice on ways to improve the stitch quality.
The images were taken with a Sony NEX5 (although were downsampled to 2MP), have 60% front and sidelap, and the overall flight path was flown in a crosshatch pattern, such that the entire area was covered twice, with a 90deg rotation between each full coverage (to ensure at least one flight path is not aligned with the corn rows). Each image was tagged with GPS info when captured, from a GPS devie with +/-3m accuracy. A sample image can be viewed / downloaded here:
https://www.dropbox.com/s/pbdud431ouldyfq/pict20140923_160305_0.jpg?dl=0The Photoscan workflow used high accuracy settings in each stage, photo alignment was optimized after the align stage, reprojection error was limited to 1 and the bounding box was fitted to the exact area of interest. The report can be downloaded here:
https://www.dropbox.com/s/qohjnrsx8r2rbvg/report.pdf?dl=0I have experimented with different aerial capture approaches - higher overlap, single flight paths (rather than the crosshatch pattern), higher altitudes, etc., and have had some improvements, but still run into the same issues in the center of large homogenous areas such as corn fields, so was hoping there might be improvements I could make to my photoscan workflow?
Any advice / suggestions would be greatly appreciated, and let me know if you want more details on any aspect of the image acquisition / photoscan workflow I've used.
Thanks