First it shows the finished hand rotating in 3d space, then explains how the computer built the image using polygon points placed on Catmull's left hand.
It proved that the approach based on spectral polygon can be used to similarity measure and image retrieval effectively because of its synthetic applications to albedo and wavelength information.
Therefore, the size of the equilateral polygon can be uniquely extracted by its front-projection image and the photogrammetric calibration can be done accordingly.