3D laser measurement system for large scale architectures using multiple mobile robots

In order to construct three dimensional shape models of large scale architectures by a laser range finder a number of range images are normally taken from various viewpoints and these images are aligned using post-processing procedure such as ICP algorithm. However in general, before applying ICP algorithm, these range images have to be registered to correct positions roughly by a human operator in order to converge to precise positions. In addition, range images must be overlapped sufficiently each other by taking dense images from close viewpoints. On the other hand, if poses of the laser rangefinder at viewpoints can be identified precisely, local range images can be converted to the world coordinate system directly with simple transformation calculation. This paper proposes a new measurement system for large scale architectures using a group of multiple robots and an on-board laser range finder Each measurement position is identified by the highly precise positioning technique named Cooperative Positioning System or CPS which utilizes the characteristics of multiple robots system. The proposed system can construct 3D shapes of large scale architectures without any post-processing procedure such as ICP algorithm and dense range measurements. The measurement experiments in unknown and large indoor/outdoor environments are successfully carried out using the newly developed measurement system consisting of three mobile robots named CPS-V.