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Accuracy in target center evaluation using Riegl LMS Z390i laser scanner and Riscan Pro software

100%

Krelling P. C. L. , Gonzalez-Jorge H. , Martinez-Sanchez J. , Arias P.

tom Vol. 42, nr 4

773--781

Terrestrial laser scanners are important instruments in architecture, civil engineering, cultural heritage, mining and industry. The accuracy of the system is determined from several parameters of influence (type of laser, quality of encoders, stability of the tripod, measurement range and changes in the environmental conditions). The surveying of large objects requires a number of base stations and a registration process to obtain a point cloud in the same reference system. The registration is typically done using targets fixed on the object surface and the determination of their center is an important source of error. In this work, the accuracy in the evaluation of the center of the targets, using the scanner Riegl LMS Z390i and its software Riscan Pro, is calculated for a set of horizontal and vertical angles. Riscan software automatically detects the center of the targets using intensity based segmentation and the geometrical calculations. Comparing the coordinates obtained from the laser scanner system software and the ground truth, an increasing in the error with the decreasing of the incident angle is observed. A linear fit is used for the study of the trend and there are not important differences between the type of target (circular or square) and the type of angle (horizontal or vertical).

Evaluation of road signs using radiometric and geometric data from terrestrial LiDAR

100%

Gonzalez-Jorge H. , Riveiro B. , Armesto J. , Arias P.

Optica Applicata

2013

tom Vol. 43, nr 3

421--433

Maintenance works are crucial to reduce the risk of accidents. Road signs appear to be one of the most important elements for safety purposes so their inspection is commonly included in the most extended road management systems. The geometric state of the sign is of great importance, especially interesting is its flatness and the inclination relative to the ground. Road signs are printed with reflective paints to maximize the visibility to the drivers. This coating produces a high reflected radiation that is easily recorded by the photoelectric detector of the laser scanner mechanisms. It allows establishing an intensity based filter in order to perform the 3D classification of the road sign. In this work, a number of road signs are evaluated, under a geometric point of view, using the laser scanner Riegl LMS Z390i. A Matlab algorithm is developed for all the data processing (3D classification and evaluation of geometric parameters). Results do not show the evidence of folded or abnormally tilted signs. The developed algorithms open the possibility of using the attribute of intensity of laser scanning data for classification purposes, during the automatic evaluation of the condition state of road signs. Such algorithms could increase the productivity and reliability of the inspection works.