Documentation of a sculptural element using Photogrammetry

Test subject

In August I shot a variety of sculptural objects with a mind towards testing the capabilities of photogrammetric software to create useful point cloud descriptions of objects that are difficult to assess conventionally. This urn represents a little of both – parts of its form is sculptural, organic, non repeating, while parts are more classical or architectural in  nature.

Photo with magnifying glass (or ‘loupe’) in Elcovision software

For this study I processed 72 photographs which consisted of three sets of images: two rings around the urn at 16mm and a half arc at 50mm (spatial constraints made it impossible to go all the way around at 50mm).

Point Cloud and photo stations (in red)

60,000 points were generated to describe the urn itself.  When viewed orthographically the point cloud behaves like a drawing – or can be the basis for a measured drawing.  The sculptural relief of the figures still escapes precise documentation in the point cloud, I think.  Laser scans still do this fine detail better, it seems.  But this point cloud – even as it is – in combination with  the photographs do so much more than what photogrammetry was able to do even a year or so ago. I think its catching up to laser sourced point clouds and doesn’t require the huge equipment investment.

Orthographic View of Point Cloud
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