1,895 research outputs found
Method to Automatically Register Scattered Point Clouds Based on Principal Pose Estimation
Three dimensional (3-D) modeling is important in applications ranging from manufacturing to entertainment. Multiview registration is one of the crucial steps in 3-D model construction. The automatic establishment of correspondences between overlapping views, without any known initial information, is the main challenge in point clouds registration. An automatic registration algorithm is proposed to solve the registration problem of rigid, unordered, scattered point clouds. This approach is especially suitable for registering datasets that are lacking in features or texture. In general, the existing techniques exhibit significant limitations in the registration of these types of point cloud data. The presented method automatically determines the best coarse registration results by exploiting the statistical technique principal component analysis and outputs translation matrices as the initial estimation for fine registration. Then, the translation matrices obtained from coarse registration algorithms are used to update the original point cloud and the optimal translation matrices are solved using an iterative algorithm. Experimental results show that the proposed algorithm is time efficient and accurate, even if the point clouds are partially overlapped and containing large missing regions
A performance test for a fringe projection scanner in various ambient light conditions
Optical triangulation based scanners have been widely used in industry, mainly for reverse engineering applications and freeform inspection tasks. Error contributions of these optical scanners include many influencing factors like surface quality and material properties of measurand, orientation and scan depth of sensors, ambient light changes, etc. This paper presents a performance evaluation test for a commercially available structured light scanner, under different ambient light conditions. The freeform reference standard developed by National Physical Laboratory is used to identify the influence of ambient light changes to the measurement accuracy
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Gardening time: Monuments and landscape from Sardinia, Scotland and Central Europe in the very long Iron Age
Gardening may seem worlds away from Nuraghi and brochs, but tending a garden is a long process involving patience, accretion and memory. Scholars argue that memories are also cultured, developed and regained. The monuments in Scotland and Sardinia are testament to the importance of memory and its role in maintaining social relations.
This collection of twenty-one papers addresses the theme of memory anchored to the enduring presence of monuments, mainly from Scotland and Sardinia, but also from Central Europe and the Balkans.This book, and the conference upon which it was based, were funded by The ACE Foundation, The Fondazione Banco di Sardegna and the McDonald Institute. We are grateful to the British School at Rome and Magdalene College, Cambridge for their support
Identification of dermestid beetle modification on Neolithic Maltese human bone: Implications for funerary practices at the Xemxija tombs
Taphonomic modifications to Neolithic human skeletal remains from six rock-cut tombs in Malta has provided key information about funerary practices and the local environment. Application of microscopic analysis, computed tomography (CT) scanning, and 3D imaging of the modifications has allowed their comparison with similar examples in modern and archaeological skeletal material. The modifications are interpreted as pupal chambers and feeding damage by dermestid beetles. Based on observation of the behaviour and ecology of dermestid beetles, we suggest several scenarios for funerary practices at the Xemxija tombs which nuance our current understanding of collective burial during the late Neolithic in Malta.Magdalene College, Cambridg
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