The optical stereo pipeline described in the course is a simplified version of the S2P pipeline [1], which was developed for high resolution pushbroom satellites such as Pleiades or WorldView. One of the particularities of these satellites is that the attitude of the satellite is known with high accuracy (about 50 μrad for Pleiades for instance). This implies that the pointing error in the yaw axis is locally zero, and that roll and pitch can be corrected by a translations in image space [2,3]. For satellites such as SkySat from Planet this pointing error is larger [4] (about 50 meters on the ground). This implies that the yaw error cannot be neglected anymore during the stereo rectification stage. The SkySat satellites are push-frame, meaning that they form large images by combining series of snapshots.
The objective of this project is to adapt the 3D pipeline presented in this course to handle SkySat stereo and tristereo products. For that, the rectification stage of the pipeline must be adapted to handle in-plane rotations in the stereo pairs. Finally, in order to produce a single DSM from a series of snapshots, the DSMs computed from selected pairs must be combined.
Supervision
Gabriele Facciolo, Carlo de Franchis, Enric Meinhardt
Bibliographic References
[1] C. de Franchis, E. Meinhardt-Llopis, J. Michel, J-M Morel, G. Facciolo. An automatic and modular stereo pipeline for pushbroom images, ISPRS Annals, 2014
[2] H. Schmid. An analytical treatment of the problem of triangulation by stereophotogrammetry. Photogrammetria, 13:67–77, 1 1956.
[3] G. Dial and J. Grodecki. RPC replacement camera models. Proc. ASPRS Annual Conference, Baltimore, pages 1–5, 2005.
[4] PLANET IMAGERY PRODUCT SPECIFICATIONS, https://www.planet.com/products/satellite-imagery/files/Planet_Combined_Imagery_Product_Specs_December2017.pdf
