Carving a Dinosaur

This is a demo of reconstructing a 3D shape from multiple images using space-carving.

This is a demo of reconstructing a 3D shape from multiple images using a simple space-carving approach. This technique is usually used when you need a 3D model of a small artefact which can be placed on a turntable, allowing dozens, even hundreds of images to be captured from around the object. It has been used pretty successfully by museums and the like to create online virtual galleries.
Each image is just used as a mask or silhouette. A lump of voxel "clay" is placed in the middle of the scene and from each image we simply look and see what is outside the object silhouette. Anything outside is carved away. Obviously, this requires us to know where the camera was relative to the object when the picture was taken, which is a whole separate problem.

This technique has been refined over the last decade and can be done in some computationally and memory efficient ways. My approach is neither of these - I went for simplicity over efficiency since my only aim was to explain the technique and show it in MATLAB.

Acknowledgements

The dinosaur images used here were provided by Wolfgang Niem at the University of Hannover.

The camera data used in this example was provided by Dr A. W. Fitzgibbon and Prof A. Zisserman from the University of Oxford Robotics Research Group.

The images and camera data can both be downloaded from the Visual Geometry Group web-pages at the University of Oxford Robotics Research Group. They are not included with the demo code.