Consistent ICP for the registration of sparse and inhomogeneous point clouds

In this paper, we derive a novel iterative closest point (ICP) technique that performs point cloud alignment in a robust and consistent way. Traditional ICP techniques minimize the point-to-point distances, which are successful when point clouds contain no noise or clutter and moreover are dense and more or less uniformly sampled. In the other case, it is better to employ point-to-plane or other metrics to locally approximate the surface of the objects. However, the point-to-plane metric does not yield a symmetric solution, i.e. the estimated transformation of point cloud p to point cloud q is not necessarily equal to the inverse transformation of point cloud q to point cloud p. In order to improve ICP, we will enforce such symmetry constraints as prior knowledge and make it also robust to noise and clutter. Experimental results show that our method is indeed much more consistent and accurate in presence of noise and clutter compared to existing ICP algorithms

Investigation of the Effect of Blade Sweep on Rotor Vibratory Loads

The effect of helicopter rotor blade planform sweep on rotor vibratory hub, blade, and control system loads has been analytically investigated. The importance of sweep angle, sweep initiation radius, flap bending stiffness and torsion bending stiffness is discussed. The mechanism by which sweep influences the vibratory hub loads is investigated

Transcriptomic analysis of Ascaris suum larvae during their hepatopulmonary migration

Common roundworms are important intestinal nematodes of man (Ascaris lumbricoides) and pig (Ascaris suum). During the first stages of the infection, the larvae of these parasites undergo a hepatopulmonary migration. This migration is likely to require tightly regulated transcriptional changes in the parasite. We explored this aspect in Ascaris suum by characterizing the transcription profiles of infective L3s from eggs, liver- and lung-L3s and intestinal L4s by next generation sequencing approach. When the most abundant transcripts per life stage were investigated, results showed that in the egg-L3s, transcripts associated with the regulation of translation and transcription, mainly ribosomal proteins, were most abundant. From the liver-L3s onwards, high transcription levels were seen for cuticle collagens, indicating the growth of the larvae during their migration. Interestingly, the type of highly expressed cuticle collagens in the intestinal L4s differed with those present in the liver- and lung-L3s. Apart from collagens, potentially important molecules for host-parasite interaction like C-type lectin-4 and Mucin-5 were in the top 5 of most abundant transcripts in the lung-L3. Unfortunately, a great number of transcripts that are specific for certain larval stages did not show any homology to other proteins within the NCBI database, suggesting that many biologically interesting molecules from this parasite are still to be investigated

Towards online mobile mapping using inhomogeneous lidar data

In this paper we present a novel approach to quickly obtain detailed 3D reconstructions of large scale environments. The method is based on the consecutive registration of 3D point clouds generated by modern lidar scanners such as the Velodyne HDL-32e or HDL-64e. The main contribution of this work is that the proposed system specifically deals with the problem of sparsity and inhomogeneity of the point clouds typically produced by these scanners. More specifically, we combine the simplicity of the traditional iterative closest point (ICP) algorithm with the analysis of the underlying surface of each point in a local neighbourhood. The algorithm was evaluated on our own collected dataset captured with accurate ground truth. The experiments demonstrate that the system is producing highly detailed 3D maps at the speed of 10 sensor frames per second