{"id":313,"date":"2014-06-02T21:02:38","date_gmt":"2014-06-02T20:02:38","guid":{"rendered":"http:\/\/pimpaud.free.fr\/wordpress\/?page_id=313"},"modified":"2020-03-14T01:08:45","modified_gmt":"2020-03-14T00:08:45","slug":"pointcloud-registration-and-texture-extraction-en","status":"publish","type":"page","link":"https:\/\/www.archeo3d.net\/?page_id=313","title":{"rendered":"Pointcloud registration and texture extraction [EN]"},"content":{"rendered":"
[here is a 2012 tutorial, outdated, but for the record]<\/pre>\n
A case study : the epigraphic survey at the Ramesseum<\/h3>\n
As a member of the French Archaeological Mission to Western Thebes<\/strong> (MAFTO<\/a>) leaded by Dr. Christian Leblanc, I have been working with Dr. Philippe Martinez, egyptologist and epigraphist, and Kevin Cain, founder and director of INSIGHT<\/a>, at the implementation of a pipeline involving pointcloud data extraction derived from both Structure from Motion (SfM) and ground truth scanned data. The aim was to benefit from the geometric accuracy of the last one, and from the texture information conveyed by the first one, in order to obtain an accurate 3D textured model that may be used as a trustfully document supporting the epigraphic survey process of the hieroglyphic inscriptions of the temple of Ramses II in Western Thebes (production of orthophotographs from any kind of architectonical components, such as columns, lintels, walls, etc.).<\/p>\n
The final idea was to define a fully automatic process to be applied to the whole monument, but for some reasons it wasn’t possible to achieve that point yet know, so we finally managed to propose a partially manual approach which is conceivable to implement. We decided to proceed to an experimentation on the Coronation Scene of the wall located in the Second Court of the Temple of Ramses II.<\/p>\n
\"The<\/a>
Figure 1. The Coronation Wall in the Ramesseum. \u00a9 Ph. Martinez<\/p><\/div>\n
The ground truth pointcloud was provided by INSIGHT. The product used in this tutorial is a mesh generated after a Poisson reconstruction filter has been applied the point set. The SfM 3D reconstruction is derived from a set of photographs taken by Philippe Martinez<\/strong>, Yann Rantier<\/strong> (MAFTO) and Mark Eakle<\/strong> (INSIGHT).<\/p>\n
\"Ground<\/a>
Figure 2. Ground truth mesh from scanned pointcloud. \u00a9 INSIGHT<\/p><\/div>\n
The Structure from Motion toolkit used is VisualSFM (version 0.5.20)<\/a><\/strong>, developped by Changchang Wu<\/strong> of the University of Washington at Seattle. The dense reconstruction is processed with CMVS<\/a><\/strong>\/PMVS<\/a><\/strong> developped by Yasutaka Furukawa<\/strong>, University of Washington, and Jean Ponce<\/strong>, \u00c9cole Normale Sup\u00e9rieure. The pointcloud and the mesh were displayed and edited with Meshlab (version 1.3.2)<\/a><\/strong>, developed at the Visual Computing Lab of the ISTI-CNR \/ University of Pisa (Italy), and we are currently exchanging with Matteo Dellepiane<\/strong> about the implementation of an automatical approach of the processes described below.<\/p>\n
For a whole background of this project, please have a look to \u00ab\u00a0A Decade of Digital Documentation at the Ramesseum\u00a0\u00bb<\/a>, available on the INSIGHT website<\/a>.<\/p>\n
N.B. : <\/strong>This experimentation is for me a side project and its outcome will definitively be profitable to my main project, the Archaeological Map of the Western Thebes, that I will present hereby soon.<\/p>\n
<\/p>\n
1. Production of the sparse and dense pointclouds<\/h2>\n
This part is straightforward and consists in following the steps mentioned in the front page of the VisualSFM website<\/a>.<\/p>\n