Synchronization-free top-down illumination photometric stereo imaging using light-emitting diodes and a mobile device

Three dimensional reconstruction of objects using a top-down illumination photometric stereo imaging setup and a hand-held mobile phone device is demonstrated. By employing binary encoded modulation of white light-emitting diodes for scene illumination, this method is compatible with standard lighting infrastructure and can be operated without the need for temporal synchronization of the light sources and camera. The three dimensional reconstruction is robust to unmodulated background light. An error of 2.69 mm is reported for an object imaged at a distance of 42 cm and with the dimensions of 48 mm. We also demonstrate the three dimensional reconstruction of a moving object with an effective off-line reconstruction rate of 25 fps.