In this paper, we present a robust global approach for point cloud registration from uniformly sampled points. Based on eigenvalues and normals computed from multiple scales, we design fast descriptors to extract local structures of these points. The eigenvalue-based descriptor is effective at finding seed matches with low precision using nearest neighbor search. Generally, recovering the transformation from matches with low precision is rather challenging. Therefore, we introduce a mechanism named correspondence propagation to aggregate each seed match into a set of numerous matches. With these sets of matches, multiple transformations between point clouds are computed. A quality function formulated from distance errors is used to identify the best transformation and fulfill a coarse alignment of the point clouds. Finally, we refine the alignment result with the trimmed iterative closest point algorithm. The proposed approach can be applied to register point clouds with significant or limited overlaps and small or large transformations. More encouragingly, it is rather efficient and very robust to noise. A comparison to traditional descriptor-based methods and other global algorithms demonstrates the fine performance of the proposed approach. We also show its promising application in large-scale reconstruction with the scans of two real scenes. In addition, the proposed approach can be used to register low-resolution point clouds captured by Kinect as well.
Developing cheap and stable membrane electrode assembly for proton exchange membrane water electrolysis (PEMWE) plays critical roles in renewable energy revolution. Iridium is the commonly efficient oxygen evolution reaction catalyst. But the reserve in earth is a shortage. Herein, an ordered array electrode in feature of the defective Ir film decorated on external WO x nanorods (WO x NRs) is designed. Electrodeposition is carried out to prepare an iridium coating (∼68 nm in thickness) to guarantee the ordered morphology. This novel electrode obtained brilliant I−V performances (2.2 A cm −2 @2.0 V) and 1030 h stability (0.5 mA cm −2 ) with a reduced loading of 0.14 mg Ir cm −2 . The uniform dispersion Ir catalyst on the WO x substrate benefits to enhance Ir mass activity and improve the poor conductivity originating from WO x . Compared with that of sprayed electrode, the threshold current density of mass transport polarization region can be expande to at least 3.0 A cm −2 for ordered structure electrode attributed to the abundant water storage bulk. This novel Ir@WO x NRs electrode occupies a huge potential to defuse the cost and durability issues confronting with the PEMWE.
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