Point-based indoor on-site self-calibration for terrestrial laser scanner
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Date
2014
Authors
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Journal ISSN
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Publisher
Universiti Teknologi Malaysia
Abstract
Similar to other instruments in Geomatics field, the results of terrestrial laser scanner can be impaired by errors coming from numerous sources. Furthermore, the external measurement conditions also can affect the magnitude of errors in terrestrial laser scanner measurement. This knowledge has led to the requirement of on-site calibration. Through point-based self-calibration, this research has investigated the suitability of lowering the network configuration requirements to improve existing calibration approaches for on-site application. Investigations began by assessing the capability of self-calibration to improve the accuracy of terrestrial laser scanner data and the effects of the choice of datum constraints. The identification of minimum network configurations were carried out by analysing three important elements, which are the minimum number of scan stations, the minimum number of surfaces on which targets are distributed and the minimum number of targets. For evaluation purpose, the developed method was implemented for an actual application that requires accurate information. The results show the significance of the selfcalibration to improve the quality of raw data up to 50 percents and datum constraints selection analyses have shown no significant effect to the parameters correlation. With the aid of close-range photogrammetry technique for benchmarking, the research found that a minimum configuration of two scanning stations, two surfaces and 16 targets for point-based self-calibration able to provide accuracy of 2mm which is significantly similar to the accuracy yielded from optimal configuration. With this on-site calibration method, two industrial objects were scanned. By utilising four quantitative analyses, the results have statistically verified the reliability of developed method to improve the quality of terrestrial laser scanner measurement in the field. With a relatively simple in implementation, this developed calibration method is expected to be valuable for a wide variety of terrestrial laser scanner applications especially for task requiring high accuracy
Description
Thesis (PhD. (Geomatics Engineering))
Keywords
Geomatics, Surveying