Public defence in geoinformatics, Lic. Sc. (Tech.) Matti Kurkela
3D point clouds expand the range of applications that utilize light measurement
The dissertation developed measurement processes in which individual points in 3D point clouds were stored with a value describing the amount of light, i.e. a luminance value. In addition, case studies demonstrated point cloud reconstruction methods, the performance and calibration of instruments, and various applications and workflows related to luminance point cloud reconstruction.
The purpose of the study was to describe equipment calibration and workflows for evaluating 3D luminance measurement methods. The 3D measurement methods were terrestrial laser scanning, mobile laser scanning and photogrammetry. In point cloud reconstruction of luminance measurements, luminance images are combined with different 3D measurement methods to produce 3D luminance point clouds. In general, the third dimension has been neglected in luminance measurements.
The results showed that luminance measurements can be combined with laser scanning and photogrammetry, which could simultaneously solve the positions and orientations of the cameras and the geometry of the object. In addition, the methods developed in the dissertation made it possible to transfer the dynamic range contained in the 16-bit luminance image to 3D points. The target luminance chosen for static road lighting luminance measurements was 0.01-2.88 cd·m-2 for a single measurement. In road lighting measurements performed with mobile laser scanning, the target luminance range of the digital single lens reflex camera ranged from 0.44 to 27.97 cd·m-2, and the range of the panoramic camera system ranged from 0.99 to 8.63 cd·m-2. In static indoor luminance measurements, the dynamic range of the terrestrial laser scanner reached 4.3-443.6 cd·m-2.
The developed luminance measurement methods expand the range of possible applications. 3D luminance measurements enable the evaluation of ergonomics, energy consumption and lighting changes in indoor spaces. Measuring road and street lighting conditions in the outdoor environment enables maintaining safety and driving comfort. 3D luminance measurements performed with mobile laser scanning enable the collection of data also from wide road and street environments.
Opponent: Professor Rauno Heikkilä, University of Oulu, Suomi
Custos: Assistant Professor Matti T. Vaaja, Aalto University School of Engineering, Department of Built Environment
Contact information of the doctoral student: Matti Kurkela, [email protected], +358 50 576 0234
The public defence will be organised on campus (auditorium M1, Otakaari 1).
The thesis is publicly displayed 10 days before the defence in the publication archive Aaltodoc of Aalto University.