What is photogrammetry?

The 3D scanning process we use to go from an object in the real world – like your house – to a miniature inside a snowglobe, is called photogrammetry. For this application it can be a time-consuming and complicated four step process, which is honestly a little hard for us to explain. But we’re going to try!

Wikipedia defines photogrammerty as

“the science of making measurements from photographs, especially for recovering the exact positions of surface points. Photogrammetry is as old as modern photography, dating to the mid-19th century and in the simplest example, the distance between two points that lie on a plane parallel to the photographic image plane, can be determined by measuring their distance on the image, if the scale (s) of the image is known.

Photogrammetric analysis may be applied to one photograph, or may use high-speed photography and remote sensing to detect, measure and record complex 2-D and 3-D motion fields by feeding measurements and imagery analysis into computational models in an attempt to successively estimate, with increasing accuracy, the actual, 3-D relative motions.”

For a 3D scan, we go through the following steps:

  1. Look at the video and find corresponding features in different images, then use the positions of those features to determine the position of the cameras that took the photos.
  2. Use the photos and camera positions to place points in space for features we can see in multiple photos… and fill in holes.
  3. Turn those points into a 3d mesh, and use gradients in the photos to further shape that mesh.
  4. Use the original photos to paint the mesh with the best photo data we have.

Hmmm. Clear as muddy snow?

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