Shape from depth discontinuities under orthographic projection

We present a new method for reconstructing the 3-D sur- face of an opaque object from the motion of its depth dis- continuities, when viewed under orthographic projection as the object undergoes rigid rotation on a turntable. A novel shape completion scheme is introduced to fill in gaps in the recovered surface, which would otherwise be impossi- ble to reconstruct from the motion of the depth discontinu- ities alone. To verify the basic theory, we construct a large- format orthographic multi-flash camera capable of recover- ing the depth discontinuities using controlled illumination. We analyze the limitations of multi-flash depth edge detec- tion using orthographic imaging with both point sources and directional illumination. We conclude by considering future applications for the shape completion scheme and the specialized hardware introduced in this work.