3D reconstruction of the “cave” of the great pyramid from video footage

Studies on the great pyramid of King Khufu (25092483 BCE ±25) in Egypt are numerous, but only a few surveys, which are the basis of any hypotheses on the construction of a pyramid, have been conducted. In particular, since no observation of the core of the pyramid has been made, theories about the structure are still hypothetical. In 2013, a Japanese TV production company had the opportunity to climb the northeast corner of the pyramid to shoot a crevice that led to an open space (named “cave”) inside the pyramid, located about 80m from the ground. The authors are fortunate to be allowed to use this video footage for academic research. We employed a “structure from motion” (SfM) technique using Microsoft Photosynth to reconstruct the 3D point cloud of the surface of the cave. Twenty minutes of footage was split into thirty thousand image frames, out of which we selected three hundred images shot using several smooth motions of the camera and used these for the SfM process. SfM tracks the “feature points” in the image sequence to estimate the camera motion and then triangulates these feature points to produce the point clouds. As a result, the static feature points from the overall surface of the cave were effectively collected and reconstructed as point clouds, whereas inconsistent points from a moving person are automatically eliminated through the SfM process. Thus we have produced, albeit in a small area, the first record of the actual structure of the great pyramid´s core. The production of a 3D model from existing video footage is a rather new methodology in the field of archaeology. This set of techniques can be applied to not only academic investigation but also to the restoration and conservation of damaged heritage and artifacts.