Search

An improved Iterative Closest Point(ICP) method based on the boundary feature points of the point cloud is proposed to improve the efficiency and accuracy of point cloud data registration in reverse engineering fields.First,an initial registration method based on the boundary feature points of point cloud is proposed.The method partitions the minimum bounding box of point cloud with grids in a 3D space,and sets up the space grid model.Then,it applies boundary seed grid recognition and growth algorithms to extract feature points from the boundary of point cloud,and works out the transformation matrix using Singular Value Decomposition(SVD) method to get the results of initial registration.Furthermore,an improved ICP accurate registration method is presented.It weighs the corresponding points of the point cloud,eliminates the points whose weight is larger than the threshold,and introduces M-estimation to the objective function to eliminate the abnormal points.Finally,the point cloud is accurately registered by the improved ICP method on the basis of initial registration.Compared with original ICP method,the improved ICP method increases the efficiency by more than 70 percent and reduces the error to 0.02 percent.The experiment results indicate that the method proposed in this paper improves the efficiency and accuracy of point cloud registration greatly.

Using the optical guided wave method,the full leaky waveguide mode assembled by prism,matching fluid of refractivity and twisted nematic liquid crystal cell is studied under different voltages.Some experimental data of reflected light corresponding to different external angles through the full leaky guided mode of twisted nematic liquid crystal are obtained.From Snell law,some experimental curves between the reflectivity and the internal angle are also obtained.By comparing these experimental curves with the theoretical curves obtained from multi-layer optics theory,with a greatly good accordance,the director profile of twisted nematic liquid crystal cell for different voltages is determined.

A novel iridium complex with sterically bulky camphor-derives group as β-diketonate,i.e.,(2-phenylpyridinato-N,C2′) irdium(Ⅲ)(3-acetyl-camphor) [Ir(ppy)2(acam)],was synthesized and it was characterized by 1H NMR,ESI-MS,and elementary analysis.This complex exhibited a higher phototoluminescence quantum efficiency(0.54) than(2-phenylpyridinato-N,C2′) irdium(Ⅲ)(acetylacetonate) [Ir(ppy)2(acac)](0.34) in 2-methyl-tetrahydrofuran solution.Efficient green phosphorescent polymer light-emitting diodes using Ir(ppy)2(acam) as dopants showed high efficiencies and stable EL spectra,with maximum current efficiency of 15.1 cd/A,maximum power efficiency of 4.23 lm/W and maximum brightness of 9 939 cd/m2 at doping mass fraction of 1%.