Dear PhotoScan users,
For a recently published book on non-invasive archaeological survey methods (
http://www.springer.com/social+sciences/anthropology+%26+archaeology/book/978-3-319-01783-9), the editors asked me to give an overview of the most recent ways of turning archaeological aerial photographs into accurate orthophotographs. Together with my co-authors, I used this opportunity to go into some details on both the imaging process as well as the Structure from Motion and Multi-View Stereo that follow.
In essence, we tried to tackle everything from data acquisition to final orthophoto product. This way, we elaborate on the “obliques versus verticals” debate in archaeology and how this relates to interpretation and mapping accuracy. Afterwards, it is explained which main factors result in geometrical image deformations (lens distortions, tilt and relief displacements) and how camera calibration tries to model the internal geometry of the complete imaging system (all terminology related to this field is explained as well). Afterwards the Structure from Motion and Multi-View Stereo steps are detailed and exemplified using PhotoScan. The idea was to not overload the text with technical details, but just mention enough jargon to make most ideas and concepts of this approach clear.
Despite many conversations, Springer still managed to introduce errors in some figures (lost capitalization on places where it matters, Greek symbols that became Latin symbols, displacement of some text), but nothing is so severe that it should hamper your understanding of the matter.
For those interested, the book chapter can be found here:
https://www.academia.edu/5901490/Undistorting_the_past_New_techniques_for_orthorectification_of_archaeological_aerial_frame_imageryor here:
https://www.researchgate.net/publication/259934911_Undistorting_the_past_New_techniques_for_orthorectification_of_archaeological_aerial_frame_imageryThe full reference of this book chapter is: Verhoeven, G., Sevara, C., Karel, W., Ressl, C., Doneus, M., Briese, C., 2013. Undistorting the past – New techniques for orthorectification of archaeological aerial frame imagery, in: Corsi, C., Slap?ak, B., Vermeulen, F. (Eds.), Good practice in archaeological diagnostics. Non-invasive survey of complex archaeological sites. Natural Science in Archaeology. Springer International Publishing, Cham, pp. 31–67. DOI: 10.1007/978-3-319-01784-6_3.
Best regards,
Geert