Friday 30 March 2012

Confuciusornis - gathering 3D data from a museum exhibit

A couple of weeks ago I took a trip up to Manchester Museum to peruse the excellent fossil gallery and test out my new camera (a Fuji x10). Whilst there my eye was caught by a rather fine fossil of the Lower Cretaceous bird Confuciusornis sanctus, from the Jianshangou Bed of the Yixian Formation (the label in the cabinet gives the location as the Chaomidianzi Formation but according to Wikipedia[!] this is a synonym for the Jianshangou Bed and has fallen out of use; the ref citied in the wiki is behind a paywall and so I can't access it to check), West Laioning Province, China. I thought it might be worth trying to gather 3D data from the fossil using the technique of photogrammetry. Although the specimen is behind glass I got good data, and here are the results.



The first image is a conventional photograph taken from directly in front of the fossil. I've adjusted the levels in the image to bring out the detail. Note the rather wonderful feather impressions of the wings and the fuzz on the neck.



This is the 3D data generated from the photographs taken for reconstruction using photogrammetry. There were 38 images in all, and these were combined to generate the above mesh. The bones are clearly visible, and the feathers of the left (our right, we're looking at the front of the bird) wing are also visible. The rectilinear features visible on this mesh are possibly artefacts of the alignment of the photos, perhaps due to subtle changes in the way each photo was lit or having the glass in-between the camera and the subject. However, I'd have to check this - oh for the luxury of on-site processing!



Above is an unadjusted render of the final textured mesh. Below is a close-up of the final mesh, with the camera positioned at a jaunty angle which shows off the quality of the model. This is lit with a single omni light with ambient occlusion active.


The quality of the mesh is well displayed in this image, and enables us to examine the fossil from all angles and also by loading the model into a viewer we can take a high-quality 3D model of this fossil anywhere we can take our laptops, iPads or smartphones. This is an effective way of accessing fossils, gathering usable data which is readily available at any time, and creating a record of the specimen which is useful for research.

5 comments:

  1. Very cool! What software did you use (or website if it's offsite processing), and what resolution on the camera? Did you use pics or video?

    ReplyDelete
  2. Thanks gents!

    I use Agisoft Photoscan to process the photographs and generate the mesh and textures and I use Cinema 4D for animating and rendering stills.

    ReplyDelete
  3. Thanks for the info! Is that the $3500 software on the Agisoft website? Eek! Might have to play with some of the freeware versions...

    Ian

    ReplyDelete
  4. The version I am using is the cheaper of the two, which I think is around $179. This is more than sufficient for my current needs, and means I won't have to sell a kidney to afford the other version.

    ReplyDelete