A self-calibrated photo-geometric depth camera

Compared with geometric stereo vision based on triangulation principle, photometric stereo method has advantages in recovering per-pixel surface details. In this paper, we present a practical 3D imaging system by combining the near-light photometric stereo and the speckle-based stereo matching method. The system is compact in structure and suitable for multi-albedo targets. The parameters (including position and intensity) of the light sources can be self-calibrated. To realize the auto-calibration, we first use the distant lighting model to estimate the initial surface albedo map, and then with the estimated albedo map and the normal vector field fixed, the parameters of the near lighting model are optimized. Next, with the optimized lighting model, we use the near-light photometric stereo method to re-compute the surface normal and fuse it with the coarse depth map from stereo vision to achieve high-quality depth map. Experimental results show that our system can realize high-quality reconstruction in general indoor environments.