Photogrammetry

From the perspective of science, it is important that the original fossils of ‘Peter’ are available for study in unaltered form. Inset into a mount on exhibit, they are not entirely out of reach, but hard to access. High resolution 3D digital models can stand in stead of the real bones for a wide variety of research questions.

There are a plethora of methods available for such 3D scanning. The most suitable for objects of complex shape and variable size is photogrammetry, an SFM (structure from motion) scanning method based on digital photography. The scans of Peter capture both the external shape and color of the fossil in high detail and are available as standard industry formats for easy usability.

Photogrammetry models are created by taking high resolution digital images of an object, with either the camera or the object or both moving between shots. Parallax between the images allows calculating the relative position of camera and object for each image position, based on a small sample of pixels (usually in the range of 10,000 to 100,000 per image). Once therelative positions are known, depth maps are calculated for each image, in which the distance of the object in the image from the camera is displayed for each pixel. From these, a simple but computationally expensive calculation can either create a high density point cloud of the object, which can then be meshed into a polygon surface, or produce a polygon model directly, depending on the software used.

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