Browsing by Author "Numers, Thomas von"

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  • Extracting surface features from laser scanner data in the nuclear waste disposal process
    (2012) Rahikka, Ville
     School of Electrical Engineering | Master's thesis
    The purpose of this thesis was to extract block stack features from laser scanner data. The edges of the stack were searched from individual laser scans and edge lines were formed from found edge points. Deposition of nuclear waste is a major topic around the world at the moment. In Sweden it has been decided to deposit the nuclear waste in tunnels mined deep underground. Nuclear waste canisters are lowered into holes drilled on the floor of the tunnels. After this the whole tunnel has to be filled tightly with bentonite clay blocks and bentonite clay pellets. The bentonite clay blocks are stacked with a massive industrial robot. Measurements with laser scanner have to be done in many phases of the deposition to enable autonomous stacking. To make stacking possible main features of the stack have to be defined from the laser scanner data. The position of the next stacking layer and assure stacking quality can be determined from these features. This thesis is part of much larger nuclear waste deposition project. There are many different phases in deposition of nuclear waste. The main focus of this thesis is the laser scanner measurements necessary for the stacking of the blocks and algorithms which are needed for extracting the stack features. First the whole nuclear waste deposition process is described in this thesis. Next equipment used in the work and the laboratory environment where measurements were taken are described. After this the sequence of stack feature extraction is explained and the algorithms used in feature extraction. For visualizing of the measurement data and for debugging of the algorithms a graphical interface was developed for this thesis. The graphical interface is used in visualization of measurements and the found features. Graphical interface was also used in controlling a linear unit and a laser scanner which were used in the test measurements. Algorithms developed in this thesis were able to find the main planes of the stack in an ideal case and in few special cases. The accuracy of the found features also met the defined criteria.
  • Hitsausparametrivalinnan tuotannolliset vaikutukset pinnoitettujen terästen pistehitsauksessa
    (1992) Numers, Thomas von
     Helsinki University of Technology | Master's thesis