Evaluation of a Low-cost Mobile Mapping and Inspection System for Road Safety Classification

This paper presents the results of an investigation about a mobile low-cost dual-DGPS system for the fast tracing of the basic road design elements (horizontal plan, long section and cross sections). It is based on the use of GPS/GNSS technology and the requirements set by the “Safety Criterion III” of vehicle movement dynamics introduced by the guidelines set by the Greek Ministry of Infrastructure, Transport and Networks. The main scope of the system is to become a useful and practical low-cost decision support tool for the inspection and the classification of road segments in safety categories based on a repeated procedure and the available vehicle fleet of the maintainer of the road. A major application task of the system could be the case of emergency conditions, i.e. to perform a quick survey of road deformation after a major disaster occurs, affecting the road infrastructure. The system consists of a moving vehicle equipped with GPS receivers. It was tested on a road segment that was accurately surveyed right after its construction (as-built) with classical surveying methods in order to verify its results. The performance of the system was evaluated on a mapping generalization base, more concerning the geometrical generalized road surface reliability and less the point mapping accuracy

LOCALIZATION OF PATHOLOGY ON COMPLEX ARCHITECTURE BUILDING SURFACES

The technology of 3D laser scanning is considered as one of the most common methods for heritage documentation. The point clouds that are being produced provide information of high detail, both geometric and thematic. There are various studies that examine techniques of the best exploitation of this information. In this study, an algorithm of pathology localization, such as cracks and fissures, on complex building surfaces is being tested. The algorithm makes use of the points’ position in the point cloud and tries to distinguish them in two groups-patterns; pathology and non-pathology. The extraction of the geometric information that is being used for recognizing the pattern of the points is being accomplished via Principal Component Analysis (PCA) in user-specified neighborhoods in the whole point cloud. The implementation of PCA leads to the definition of the normal vector at each point of the cloud. Two tests that operate separately examine both local and global geometric criteria among the points and conclude which of them should be categorized as pathology. The proposed algorithm was tested on parts of the Gazi Evrenos Baths masonry, which are located at the city of Giannitsa at Northern Greece