Masakazu Enomoto

Development of Accuracy Evaluation System for Curved Shell Plate by Laser Scanner

Accuracy evaluation system for a curved shell plate was developed. In this system, the point cloud data of a curved shell plate measured by a laser scanner and the design data are registered based on the edge of shell plates. Then the errors which mean the distances from the design surface are evaluated and visualized by color map. In addition to the development of the system, some actual curved shell plates are evaluated and visualized by this system. Some correlations between the distribution of the errors and the making process are illustrated.

Evaluating Positioning Uncertainty of Spherical Targets in Laser Scanning

Spherical targets are useful for registration of point-clouds. In this paper we discuss the positioning uncertainty by laser scanners. We measured spheres of relatively large diameter from about 9m distance, and calculated their positions by the least-squares fitting. The scanning was iterated thirty times and the standard deviations of fitting result were calculated to indicate positioning uncertainty. The result shows smaller positioning uncertainty in comparison with the range noise listed in the specifications.

Accuracy Evaluation System for Shipbuilding Blocks Using Design Data and Point Cloud Data

An accuracy evaluation system for shipbuilding blocks using design data and point cloud data by laser scanners is proposed in this paper. In this system, point cloud data obtained by laser scanner and design data are registered by extracted feature points and planes of longitudinal members. The gap between positions of feature points and surfaces of longitudinal members and shell plates extracted from point cloud data and design data are then shown quantitatively. At a measurement in a shipyard, the error in positions of longitudinal members due to inaccurate welding is evaluated by this system. The finding is a kind of knowledge for fabrication process.

DEVELOPMENT OF LOCAL POSITIONING SYSTEM USING BLUETOOTH

ABSTRACT A local positioning system utilizing propagation loss of Bluetooth wireless technology is presented. The distance between a stationary station and a mobile station (both located indoor) carried by a person is derived from the propagation loss. The position of the person is calculated from distance measurements on three different fixed stations. The positioning accuracy was 1.2m at average fixed station installation density of one station in every 8.3m2. The system is intended for tracking workers position in a work environment.