Accurate 3D acquisition of freely moving objects

This paper presents a new acquisition method for 3D laser scanners that combines imaging, fast geometrical object tracking, and automatic pose estimation to register range profiles of freely moving objects. The method was developed to solve the constraint of rigidity between free-moving objects and a 3D scanner while preserving the accuracy of the range measurements. Rigidity constraint imposes that a 3D scanner or any external positioning devices must be perfectly stable relative to the object during scanning. This is often impossible for moving structures such as when using scaffolding, industrial conveyers, or robotic arms. The method starts by creating a rough, partial, and distorted estimate of the model of the object from an initial subset of sparse range data. Then, it recursively improves and refines the model by adding new range information. In parallel, real-time tracking of the object is performed to center the scan on the object. A high-resolution and accurate 3D model of a free-floating object, and real-time tracking of its position is obtained.