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We present a novel active learning approach for shape cosegmentation based on graph convolutional networks (GCNs). The premise of our approach is to represent the collections of three-dimensional shapes as graph-structured data, where each node in the graph corresponds to a primitive patch of an oversegmented shape, and is associated with a representation initialized by extracting features. Then, the GCN operates directly on the graph to update the representation of each node based on a layer-wise propagation rule, which aggregates information from its neighbors, and predicts the labels for unlabeled nodes. Additionally, we further suggest an active learning strategy that queries the most informative samples to extend the initial training samples of GCN to generate more accurate predictions of our method. Our experimental results on the Shape COSEG dataset demonstrate the effectiveness of our approach.

The microstructure of Sn-Ag-Cu (SAC) solder joints plays an important role in the reliability of electronics, and interlaced twinning has been linked with improved performance. Here, we study the three-dimensional (3-D) shape of interlaced regions in Sn-3.0Ag-0.5Cu (SAC305) solder balls by combining serial sectioning with electron backscatter diffraction. In solder balls without large Ag3Sn plates, we show that the interlaced volume can be reasonably approximated as a hollow double cone with the common 〈100〉 twinning axis as the cone axis, and the 〈110〉 from all three twinned orientations making up the cone sides. This 3-D morphology can explain a range of partially interlaced morphologies in past work on 2-D cross-sections.

The deformable warhead is a common type of anti-missile warheads, and the geometric configuration of deformable warhead is close to D shape under the lateral blast loading of auxiliary charge. In this article, the spatial distribution of fragments is taken as the research object, and an empirical model for evaluating the spatial distribution of fragments is expected to be established. First, the empirical model was designed based on dimensional analysis and quadratic interpolation. Then, three different D-shaped structures (D-90°, D-120°, D-150°) were studied by the numerical simulations and experiments. In order to minimize the influence of the axial sparse waves at both ends, only the middlemost layer of fragments was researched. The relationships among d / r , sin α , and sin β were obtained (where d represents the initiation distance, α represents the initial position angle, and β represents the scattering angle). With the scattering angle β and target distance l , the spatial distribution of fragments can be deduced. Based on the fitting formula and the parameters of D-shaped structures, the relationships between d / r , sin α , and sin β of arbitrary D-shaped casing (D- θ ) were obtained using quadratic interpolation. Finally, D-105° structure was verified by numerical simulation and empirical formula, both of which coincided well with each other. Therefore, the empirical model can be used to rapidly evaluate the spatial distribution of fragments, especially suitable for the D-shaped structure with a large length–diameter ratio.

The shape of concrete aggregate fine particles (fines), with particle sizes between 3 µm and 250 µm, produced by high-speed vertical shaft impact (VSI) crushing of 10 different rock types from quarries in Norway, has been studied by both dynamic image analysis (DIA), which is a two-dimensional (2-D) method, and X-ray computed microtomography (µCT) coupled with spherical harmonic (SH) analysis, which is a threedimensional (3-D) method. The 3-D µCT results serve as a check on the 2-D DIA results. The intent was to evaluate the applicability of the 2-D DIA method to extract shape parameters that could represent the actual 3-D shape of the VSI crushed concrete aggregate particles. The results show that the 2-D DIA method has problems correctly measuring the shape of particles smaller than about 40 µm due to too large of a pixel size and possibly some particle flocculation. The findings of this paper show, however, that if a large enough number of particles are analysed by the 2-D DIA method, a good but limited indication of the actual 3-D shape of the irregular crushed aggregate fines larger than 40 µm can be acquired and used for simple quality control in hard rock quarries. © 2016 Elsevier B.V. All rights reserved. This is the authors' accepted and refereed manuscript to the article. Author's post-print is released with a Creative Commons Attribution Non-Commercial No Derivatives License.

Frau, L.; Marzeddu, A.; Dini, E; Gracia, V.; Gironella, X.; Erioli A.; Zomparelli, A., and Sanchez-Arcilla, A., 2016. Effects of ultra-porous 3D printed reefs on wave kinematics. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 851–855. Coconut Creek (Florida), ISSN 0749-0208. Present 3D printing technology allows the efficient design and construction of structures with complex shapes and high porosity satisfying biological and coastal protection demands. In this case, an array of ultra-porous tetrahedron-shaped 3D printed artificial reef (UPTSAR) is proposed to be used as a submerged breakwater for both environmental enhancement and wave protection. The aim of this study is to analyse the wave-structure interaction effects and the resulting velocity and wave height fields. For this, two-dimensional small scale tests (1:15) using irregular...

This paper describes the uncertainty analysis performed for the reconstruction of a 3-D shape. Multiple stereo systems are employed to measure a 3-D surface with superimposed colored markers. The procedure comprised a detailed uncertainty analysis of all measurement phases, and the uncertainties evaluated were employed to perform a compatibility analysis of points acquired by different stereo pairs. The compatible acquired markers were statistically merged in order to obtain the measurement of a 3-D shape and an evaluation of the associated uncertainty. Both the compatibility analysis and the measurement merging are based on the evaluated uncertainty.

An original procedure is presented for calibrating fringe projection-based 3D vision systems. The approach estimates both the phase-to-depth and transverse relationships by using the phase maps calculated for only three planes placed within the calibration volume. Experimental tests conducted on a fringe projection system show the effectiveness of the proposed procedure.

Last year we presented the influence of pose on threedimensional (3-D) shape classification in the context of a repeatability study. Meaning, that the subjects are repeatedly scanned 10 times and they attempt to assume the same pose each time. It was shown that changes due to a slight pose modification had no detrimental effects for shape classification. This paper discuss a second set of experiments, designed to test the stability of the geometric search engine in more extreme cases. The pose of the subjects between the scans are modified substantially, with an increasing amount of differences compared to the CAESAR protocol. Experimental results will be presented and discussed., Proceedings of the Digital Human Modeling for Design and Engineering Conference, June 26-28, 2001., Arlington, Virginia, USA

Proceedings of the Digital Human Modeling for Design Engineering, June 6-8, 2000., Dearborn, Michigan, USA

We propose new techniques for 2-D shape/contour completion, which is one of the important research topics related to shape analysis and computer vision, e.g. the detection of incomplete objects due to occlusion and noises. The purpose of shape completion is to find the optimal curve segments that fill the missing contour parts, so as to acquire the best estimation of the original complete object shapes. Unlike the previous work using local smoothness or minimum curvature priors, we solve the problem under a Bayesian formulation taking advantage of global shape prior knowledge. With the priors, our methods are expert in recovering significant shape structures and dealing with large occlusion cases. There are two different priors adopted in this paper: (i) A generic prior model that prefers minimal global shape transformation (including non-rigid deformation and affine transformation with respect to a reference object shape) of the recovered complete shape; and (ii) a class-specific shape prior model learned from training examples of an object category, which prefers the reconstructed shape to follow the learned shape variation models of the category. Efficient contour completion algorithms are suggested corresponding to the two types of priors. Our experimental results demonstrate the advantage of the proposed shape completion approaches compared to the existing techniques, especially for objects with complex structure under severe occlusion.

A new perimeter for shapes composed of cells is defined. This perimeter is called the contact perimeter, which corresponds to the sum of the boundaries of neighboring cells of the shape. Also, a relation between the perimeter of the shape and the contact perimeter is presented. The contact perimeter corresponds to the measure of compactness proposed here called discrete compactness. In this case, the term compactness does not refer to point-set topology, but is related to intrinsic properties of objects.