Tuesday 4 September 2012

SfM/IBM of old data

Hi all,
i was organizing data of a old storage media and i found some pictures of a work we did in Aramus excavation during the 2006 season.  The documentation of a walled-door was an hard test for 2D digital documentation ("metodo Aramus"). The picture below reproduces the logistic difficulty to take pictures usable for a photomosaic: due to the morphology of the site it was not possible to be in front of the wall.


Finally we took 14 photos to document an area which could be covered by only one image under normal conditions. The schema below shows the different area taken up in the 14 photos: it is bigger in the upper stripe and obviously smaller in the lowest.


A selection of the 14 photos is represented in the image below.


On the field we took also a group of images (14) from different point of view. We intended to elaborate the photo set with the software Stereo. In the end we didn't elaborate it because the 2D photomosaic reached a good quality and a sufficient accuracy. Stereo's data elaboration is time consuming and it depend totally to human work. the picture below shows six photos taken for 3D documentation.


After six years i found this data again and i tried to elaborate them using Python Photogrammetry Toolbox which is not time consuming because the artificial intelligence leads automatically the process. The result is an accurate 3D model. Is surprising that pictures taken two years before the development of Bundler could be used to create precise documentation of no more accessible archaeological context. The movie below shows the mesh of the walled-door.

  
Thank to Sandra Heinsch and Walter Kuntner (University of Innsbruck - Institut für Alte Geschichte und Altorientalistik) to share the data.

2 comments:

  1. Interesting this post. The years go and the experience comes. Thank you to post it. I was thinking that this type of work allow us do a 2D (ortho front) view of the wall with precision to do a draw like a floorplan. A big hug!

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  2. That's right!
    In this case it was simpler to do directly a 3D documentation and then extract an orthophoto from it (e.g. for vector drawing and raster analysis in GIS), but our technology was not yet "ready" in 2006. Anyway I think this will be the feature in arcaheological documentation (maybe we have to wait a little bit of computing power in the hardware).
    By the way this would be a nice test to try!

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