A robust feature-based registration method of multimodal image using phase congruency and coherent point drift

Forfatterlist

Global calibration of multi-cameras with non-overlapping fields of view based on photogrammetry and reconfigurable target

Abstract Multi-camera vision systems are often needed to achieve large-scale and high-precision measurement because these systems have larger fields of view (FOV) than a single camera. Multiple cameras may have no or narrow overlapping FOVs in many applications, which pose a huge challenge to global calibration. This paper presents a global calibration method for multi-cameras without overlapping FOVs based on photogrammetry technology and a reconfigurable target. Firstly, two planar targets are fixed together and made into a long target according to the distance between the two cameras to be calibrated. The relative positions of the two planar targets can be obtained by photogrammetric methods and used as invariant constraints in global calibration. Then, the reprojection errors of target feature points in the two cameras’ coordinate systems are calculated at the same time and optimized by the Levenberg–Marquardt algorithm to find the optimal solution of the transformation matrix between the two cameras. Finally, all the camera coordinate systems are converted to the reference coordinate system in order to achieve global calibration. Experiments show that the proposed method has the advantages of high accuracy (the RMS error is 0.04?mm) and low cost and is especially suitable for on-site calibration

PLADE: A Plane-Based Descriptor for Point Cloud Registration with Small Overlap

Traditional point cloud registration methods require large overlap between scans, which imposes strict constraints on data acquisition. To facilitate registration, users have to carefully position scanners to ensure sufficient overlap. In this article, we propose to use high-level structural information (i.e., plane/line features and their interrelationship) for registration, which is capable of registering point clouds with small overlap, allowing more freedom in data acquisition. We design a novel plane-/line-based descriptor dedicated to establishing structure-level correspondences between point clouds. Based on this descriptor, we propose a simple but effective registration algorithm. We also provide a data set of real-world scenes containing a larger number of scans with a wide range of overlap. Experiments and comparisons with state-of-the-art methods on various data sets reveal that our method is superior to existing techniques. Though the proposed algorithm outperforms state-of-the-art methods on the most challenging data set, the point cloud registration problem is still far from being solved, leaving significant room for improvement and future work.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Urban Data Scienc

Design, Synthesis, Crystal Structures, and Insecticidal Activities of Eight-Membered Azabridge Neonicotinoid Analogues

Three series of novel azabridge neonicotinoid analogues were designed and synthesized, which were constructed by starting material <b>A</b>, glutaraldehyde, and primary amine hydrochlorides (aliphatic amines, phenylhydrazines, and anilines). Most of the eight-membered azabridge compounds presented higher insecticidal activities than oxabridged compound <b>B</b> against cowpea aphid (Aphis craccivora) and brown planthopper (Nilaparvata lugens). Compared with imidacloprid, some azabridged compounds exhibited excellent insecticidal activity against brown planthopper. The crystal structures and bioassay indicated that changing bridge atoms from O to N could lead to entirely different conformations, which might be the important influential factor of the bioactivities

Design, Synthesis, Crystal Structures, and Insecticidal Activities of Eight-Membered Azabridge Neonicotinoid Analogues

Three series of novel azabridge neonicotinoid analogues were designed and synthesized, which were constructed by starting material <b>A</b>, glutaraldehyde, and primary amine hydrochlorides (aliphatic amines, phenylhydrazines, and anilines). Most of the eight-membered azabridge compounds presented higher insecticidal activities than oxabridged compound <b>B</b> against cowpea aphid (Aphis craccivora) and brown planthopper (Nilaparvata lugens). Compared with imidacloprid, some azabridged compounds exhibited excellent insecticidal activity against brown planthopper. The crystal structures and bioassay indicated that changing bridge atoms from O to N could lead to entirely different conformations, which might be the important influential factor of the bioactivities