Thursday, 28 July 2011
Python Photogrammetry Toolbox (PPT) and a turntable for 3D objects
I already answered on Pierre Moulon' Blog, but the question Tauricity did is very interesting. The question regards the possibility to document with PPT (Python Photogrammetry Toolbox) an object on a turntable, keeping the camera on a fix position. I had positive results when I tried with Giuseppe Naponiello (Arc-Team's anthropologitst) to document an human skull. We put the skull on a turntable with a black board behind (in this way the software does not recognize nothing exept the turntable and the skull); then we took a picture every 30 degrees. The only problem we had was during data elaboration, cause using PPT with Bundler 4 the software gave us a wrong result (it seems that it confused the two faces of the skull in the axial simmetry). Alessandro Bezzi helped us elaborating the data via shell and using Bundler 3 instead of Bundler 4 (cause he had a similar problem documenting the Theodoric Mausoleum in Ravenna) and this time there were no errors and we could do a dense pointcloud inside PMVS2. So it looks like that Bundler 4 has problems when objects have an axial (the skull) or a radial (the mausoleum) simmetry, but bundler 3 works perfectly.
Anyway it was possible for us to document an object on a turntable keeping the camera fix; the only tip was the black board to "erase" the background, so the software does not recognize points in it (which would be in conflict with the points of the object).
In this video is possible to see the result of the dense pointcloud.