Pose estimation of free-form objects is a crucial task towards flexible and reliable highly complex autonomous systems. Recently, methods based on range and RGB-D data have shown promising results with relatively high recognition rates and fast running times. On this line, this paper presents a feature-based method for 6D pose estimation of rigid objects based on the Point Pair Features voting approach. The presented solution combines a novel preprocessing step, which takes into consideration the discriminative value of surface information, with an improved matching method for Point Pair Features. In addition, an improved clustering step and a novel view-dependent re-scoring process are proposed alongside two scene consistency verification steps. The proposed method performance is evaluated against 15 state-of-the-art solutions on a set of extensive and variate publicly available datasets with real-world scenarios under clutter and occlusion. The presented results show that the proposed method outperforms all tested state-of-the-art methods for all datasets with an overall 6.6% relative improvement compared to the second best method.

The Point Pair Feature [4] has been one of the most successful 6D pose estimation method among model-based approaches as an efficient, integrated and compromise alternative to the traditional local and global pipelines. During the last years, several variations of the algorithm have been proposed. Among these extensions, the solution introduced by Hinterstoisser et al. [6] is a major contribution. This work presents a variation of this PPF method applied to the SIXD Challenge datasets presented at the 3rd International Workshop on Recovering 6D Object Pose held at the ICCV 2017. We report an average recall of 0.77 for all datasets and overall recall of 0.82, 0.67, 0.85, 0.37, 0.97 and 0.96 for hinterstoisser, tless, tudlight, rutgers, tejani and doumanoglou datasets, respectively.

No abstract

ABSTRACT. The present paper describes the use of a stochastic search procedure that is the basis of genetic algorithms (GA), in developing near-optimal topologies ofload bearing truss structures. The problem addressed is one wherein the structural geometry is created from a specification of load conditions and available support points in the design space. The development of this geometry must satisfy kinematic stability requirements in addition to the usual requirements of structural strength and stiffness. The approach is an adaptation of the ground-structure method of topology optimization, and is implemented in a two-level GA based search. In this process, the kinematic stability constraints are imposed at one level, followed by the treatment of response constraints at a second level of optimization. Singular value decomposition is used to assess the kinematic stability constraint at the first level of design, and results in the creation of a finite number of increasing weight, stable topologies. Member sizing is then introduced at a second level of design, where minimal weight and response constraints are simultaneously considered. At this level, the only admissible topologies are those identified during the first stage and any stable combinations thereof. The design variable representation scheme allows for both the removal and addition of structural members during optimization.

No abstract

We demonstrated InGaAs/GaAs strained quantum well lasers on silicon substrates. The epitaxial layers for lasers were first grown on a GaAs substrate and then bonded to a silicon substrate using the technology of bonding by atomic rearrangement. Covalently bonded III-V/Si heterointerface was confirmed by the cross-sectional transmission electron microscopy. The ridge waveguide lasers on Si substrates lasing at about 1 μm wavelength have a 12 mA threshold current and a 56% external quantum efficiency at room temperature, at pulsed condition. Both the threshold current and the external quantum efficiency are close to the values of lasers on GaAs substrates. The technology of bonding by atomic rearrangement will be useful for making optoelectronic integrated circuits on Si.

No abstract

No abstract