An automatic alignment technique for multiple rangefinders

An automatic alignment technique for multiple rangefinders is proposed. We obtain 3D data of object using a rangefinder which is composed of a camera and a projector. Generally, we can only obtain partial figure when we measure an object from one direction. Therefore, we can acquire all around configuration by measuring an object from multiple viewpoint. The data obtained with rangefinder exists independent camera coordinate system each other. It is needed to integrate each range maps to acquire all around figure. Heretofore, we integrate multiple range maps by estimating camera parameter using calibration rig whose scale is known. Calibration rig has many feature points which have world coordinate each. Camera parameter is estimated from the relation between camera coordinate and world coordinate of feature points on the rig. However, we cannot identify the measuring position when we measure a part of the rig, because the pattern painted on the rig is monotonous pattern. In this paper, we use "De Bruijn Sequence pattern" on the calibration rig. This pattern enables us to identify the measuring spot wherever we measure the rig, and enable us to automatically integrate multiple range maps.