Artefacts Drone2Map dans la mosaïque orthophotographique

Question

J'ai créé une mosaïque orthophotographique dans D2M. D'abord avec les paramètres par défaut et un GSD de 1. Elle contient des artefacts tout autour de la mosaïque comme ci-dessous.<\/P> <\/span><\/P>Après avoir lu certains messages dans cette communauté, j'ai modifié les paramètres, notamment en cochant "rolling shutter optimization", changé initial en full et coché "use geometry verified matching". Cela produit encore plus d'artefacts et déplace complètement l'ortho de quelques centaines de mètres.<\/P>En utilisant les paramètres par défaut, la qualité globale est correcte sauf pour ces artefacts. Merci de me conseiller comment éviter ces problèmes.<\/P>Cordialement<\/P>

DerrickWestoby · Answer

You really want to be flying with 70%+ overlap with SfM.   Keep in mind that this is based off the drone's altitude above ground level and an image footprint projected into the ground.  If you're flying over tall buildings, especially at low (<200ft) altitudes, the overlap in those areas is going to be insufficient.  You may have 70%/70% overlap at ground level, but 50%/50% on the building roof.

FrankOuyang · Answer

As suggested by @DanPatterson, capturing more images using higher overlap ratio will help reduce the artifacts, such as increase it from 60% to 80% or 90%. This will increase processing time and the output point cloud size but it can significantly improve the quality of the output.

Another thing to consider, from my experience, is try to fly the UAV at the solar noon when the shadow is minimized. By doing so, object/area of interest will have the best illumination which helps the photogrammetry algorithms identify objects and reconstruct them and eventually, reduce the chance of having artifacts.

danretired · Answer

There other related links to the right of your post, for example,

Solved: Drone2Map imagery quality - Esri Community

which suggests "overlaps" setting