Online loop closure for real-time interactive 3D scanning

We present a real-time interactive 3D scanning system that allows users to scan complete object geometry by turning the object around in front of a real-time 3D range scanner. The incoming 3D surface patches are registered and integrated into an online 3D point cloud. In contrast to previous systems the online reconstructed 3D model also serves as final result. Registration error accumulation which leads to the well-known loop closure problem is addressed already during the scanning session by distorting the object as rigidly as possible. Scanning errors are removed by explicitly handling outliers based on visibility constraints. Thus, no additional post-processing is required which otherwise might lead to artifacts in the model reconstruction. Both geometry and texture are used for registration which allows for a wide range of objects with different geometric and photometric properties to be scanned. We show the results of our modeling approach on several difficult real-world objects. Qualitative and quantitative results are given for both synthetic and real data demonstrating the importance of online loop closure and outlier handling for model reconstruction. We show that our real-time scanning system has comparable accuracy to offline methods with the additional benefit of immediate feedback and results.