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RISS 인기검색어
- 검색키워드
- 저자 : Urszula Marmol (검색결과 2 건)
- 무료
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The effect of partial transparency of spherical targets on TLS point clouds registration accuracy
Grzegorz Lenda,Urszula Marmol,Michał Buczek 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.7
Registering of point clouds from terrestrial laser scanning, is often carried out using spherical targets. Instead of expensive originaltargets, it is also possible to use other spherical elements. Such targets, encountered in practice, may be, for example, Styrofoamspheres, spheres built using 3D printers, spherical, milky lampshades. Most spheres which are used as substitutes, have a certaincommon feature: as a result of partial transparency of the material, the laser beam can penetrate inside, changing distancemeasurements. This applies both to glass spheres and a wide range of synthetic products. These materials may therefore have anegative effect on the accuracy of determining the centers of the reference spheres and, consequently, the accuracy of registrationpoint clouds in neighbouring scanners’ positions. This paper presents the results of the research studies allowing to assess this effect. Both the accuracy of determining the centers of the spherical targets, as well as the displacements occurring in the point cloudsmerged with their use were determined. Specialized field: Surveying & Geo-Spatial Engineering : Deformation Surveying
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Grzegorz Lenda,Marcin Ligas,Urszula Marmol 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.2
Shell structures belong to a characteristic group of objects for which it is essential to know the magnitude and distribution of localdeformations of the coat. Deformations may be important both in terms of stability, as well as special functions performed by theseobjects. While survey instruments usually ensure the required accuracy of the measurements, the methods for providing amathematical description of the shape of shells do not always allow for a correct detection of deformations. This paper comparesseveral methods of approximation potentially useful for making a precise description of the shape of a given shell object. Splinefunctions, as the most versatile tool in terms of description of objects shape, were adopted as the base method. For comparisonpurposes, according to the shape of the object in question, kriging and Fourier series methods were selected. Particular attention hasbeen paid to the accuracy aspect, which has enabled deformations to be determined within centimeter or subcentimeter accuracy. Results of the study revealed the greatest overall accuracy of spline functions. This accuracy however decreases quickly when theobservations become more irregular. Both, the past and future studies of the authors focus on integrating the best features of thedescribed methods in order to ensure a high accuracy of the created models. The results may be useful not only in surveying but alsoin other fields associated with the approximation of surfaces based on measurement data.
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