Registration of 3D lidar point clouds with optical images is critical in the combination of multisource data. Geometric misalignment originally exists in the pose data between lidar point clouds and optical images. To improve the accuracy of the initial pose and the applicability of the integration of 3D points and image data, we develop a simple but efficient registration method. We first extract point features from lidar point clouds and images point features are extracted from single-frame lidar and point features are extracted from images using a classical Canny operator. The cost map is subsequently built based on Canny image edge detection. The optimization direction is guided by the cost map, where low cost represents the desired direction, and loss function is also considered to improve the robustness of the proposed method. Experiments show positive results.Phase-space analysis has been widely used in the past for the study of optical resonant systems. While it is usually employed to analyze the far-field behavior of resonant systems, we focus here on its applicability to coupling problems. By looking at the phase-space description of both the resonant mode and the exciting source, it is possible to understand the coupling mechanisms as well as to gain insights and approximate the coupling behavior with reduced computational effort. In this work, we develop the framework for this idea and apply it to a system of an asymmetric dielectric resonator coupled to a waveguide.The recently proposed omnidirectional depth segmentation method (ODSM) has advantages over traditional depth segmentation in terms of robustness and computational costs. However, this method uses at least six fringe patterns and changes their sequences multiple times to perform depth segmentation, which limits its segmentation speed and increases computational complexity. This paper proposes a fast computational depth segmentation (FCDS) method in which only five patterns are used for object segmentation at different depths into isolated regions without the requirement of pattern sequence changing. Phase singularity points are fully utilized due to their significance as depth segmentation markers to extract segmenting lines used for depth determination. Meanwhile, a modified Fourier transform algorithm (MFTA) is introduced to calculate the wrapped phase sequences, which uses two groups of orthogonal phase-shifting fringe patterns and a DC component pattern (five in total). The segmenting lines along orthogonal directions can be extracted with the FCDS method without changing the fringe sequences, which not only solves the problem of phase insensitivity but reduces the calculation costs. Besides, the problem of mis-segmentation is solved with an optimization algorithm for depth segmenting lines and successfully segments objects with abrupt depth changes. The simulation results demonstrate the effectiveness and precision of the proposed method. The experimental results prove the success of the proposed method for segmenting objects of similar color with a segmentation speed that is up to a 120% increase relative to previous methods.Graphene is now a crucial component of many device designs in electronics and optics. https://www.selleckchem.com/products/3bdo.html Just like the noble metals, this single layer of carbon atoms in a honeycomb lattice can support surface plasmons, which are central to several sensing technologies in the mid-infrared regime. As with classical metal plasmons, periodic corrugations in the graphene sheet itself can be used to launch these surface waves; however, as graphene plasmons are tightly confined, the role of unwanted surface roughness, even at a nanometer scale, cannot be ignored. In this work, we revisit our previous numerical experiments on metal plasmons launched by vanishingly small grating structures, with the addition of graphene to the structure. These simulations are conducted with a recently devised, rapid, and robust high-order spectral scheme of the authors, and with it we carefully demonstrate how the plasmonic response of a perfectly flat sheet of graphene can be significantly altered with even a tiny corrugation (on the order of merely 5 nm). With these results, we demonstrate the primary importance of fabrication techniques that produce interfaces whose deviations from flat are on the order of angstroms.Scattering by a three-dimensional object composed of a chiral medium (the interior medium) and immersed in a simple Lorentz-nonreciprocal medium with magnetoelectric gyrotropy (the exterior medium) was treated using the extended boundary condition method (EBCM). The exterior medium is quantified by εre, μre, and Γ, whereas the interior medium is quantified by εri, μri, and β. When irradiated by a plane wave, the differential scattering efficiency does not depend on the polarization state of the incident plane wave if the exterior medium is impedance-matched with the interior medium, regardless of the shape of the object, Γ, and β. Zero backscattering is possible if, in addition to impedance-matching condition, the object is rotationally symmetric about the propagation direction, and Γ is parallel to the propagation direction. Numerical results confirm these remarks for scattering by spheroids. On fixing εri, μri, εre, and μre, the effects of Γ and β on the total scattering efficiency were examined for a sphere. The total scattering efficiency does not depend on the polarization state of the incident plane wave, even when the exterior medium is not impedance-matched with the interior medium, and despite the presence of Γ and β. The total scattering efficiency when Γ is coparallel to the propagation direction can be either equal to, larger than, or smaller than when Γ is antiparallel or perpendicular to the propagation direction, depending on β and the electrical size of the sphere. It is found that parallel propagation of the incident plane wave with respect to Γ has a stronger influence than perpendicular propagation, regardless of β and the electrical size of the sphere. The effect of increasing/decreasing the magnitude of Γ can be envisioned only when its direction is parallel to the propagation direction.
Registration of 3D lidar point clouds with optical images is critical in the combination of multisource data. Geometric misalignment originally exists in the pose data between lidar point clouds and optical images. To improve the accuracy of the initial pose and the applicability of the integration of 3D points and image data, we develop a simple but efficient registration method. We first extract point features from lidar point clouds and images point features are extracted from single-frame lidar and point features are extracted from images using a classical Canny operator. The cost map is subsequently built based on Canny image edge detection. The optimization direction is guided by the cost map, where low cost represents the desired direction, and loss function is also considered to improve the robustness of the proposed method. Experiments show positive results.Phase-space analysis has been widely used in the past for the study of optical resonant systems. While it is usually employed to analyze the far-field behavior of resonant systems, we focus here on its applicability to coupling problems. By looking at the phase-space description of both the resonant mode and the exciting source, it is possible to understand the coupling mechanisms as well as to gain insights and approximate the coupling behavior with reduced computational effort. In this work, we develop the framework for this idea and apply it to a system of an asymmetric dielectric resonator coupled to a waveguide.The recently proposed omnidirectional depth segmentation method (ODSM) has advantages over traditional depth segmentation in terms of robustness and computational costs. However, this method uses at least six fringe patterns and changes their sequences multiple times to perform depth segmentation, which limits its segmentation speed and increases computational complexity. This paper proposes a fast computational depth segmentation (FCDS) method in which only five patterns are used for object segmentation at different depths into isolated regions without the requirement of pattern sequence changing. Phase singularity points are fully utilized due to their significance as depth segmentation markers to extract segmenting lines used for depth determination. Meanwhile, a modified Fourier transform algorithm (MFTA) is introduced to calculate the wrapped phase sequences, which uses two groups of orthogonal phase-shifting fringe patterns and a DC component pattern (five in total). The segmenting lines along orthogonal directions can be extracted with the FCDS method without changing the fringe sequences, which not only solves the problem of phase insensitivity but reduces the calculation costs. Besides, the problem of mis-segmentation is solved with an optimization algorithm for depth segmenting lines and successfully segments objects with abrupt depth changes. The simulation results demonstrate the effectiveness and precision of the proposed method. The experimental results prove the success of the proposed method for segmenting objects of similar color with a segmentation speed that is up to a 120% increase relative to previous methods.Graphene is now a crucial component of many device designs in electronics and optics. https://www.selleckchem.com/products/3bdo.html Just like the noble metals, this single layer of carbon atoms in a honeycomb lattice can support surface plasmons, which are central to several sensing technologies in the mid-infrared regime. As with classical metal plasmons, periodic corrugations in the graphene sheet itself can be used to launch these surface waves; however, as graphene plasmons are tightly confined, the role of unwanted surface roughness, even at a nanometer scale, cannot be ignored. In this work, we revisit our previous numerical experiments on metal plasmons launched by vanishingly small grating structures, with the addition of graphene to the structure. These simulations are conducted with a recently devised, rapid, and robust high-order spectral scheme of the authors, and with it we carefully demonstrate how the plasmonic response of a perfectly flat sheet of graphene can be significantly altered with even a tiny corrugation (on the order of merely 5 nm). With these results, we demonstrate the primary importance of fabrication techniques that produce interfaces whose deviations from flat are on the order of angstroms.Scattering by a three-dimensional object composed of a chiral medium (the interior medium) and immersed in a simple Lorentz-nonreciprocal medium with magnetoelectric gyrotropy (the exterior medium) was treated using the extended boundary condition method (EBCM). The exterior medium is quantified by εre, μre, and Γ, whereas the interior medium is quantified by εri, μri, and β. When irradiated by a plane wave, the differential scattering efficiency does not depend on the polarization state of the incident plane wave if the exterior medium is impedance-matched with the interior medium, regardless of the shape of the object, Γ, and β. Zero backscattering is possible if, in addition to impedance-matching condition, the object is rotationally symmetric about the propagation direction, and Γ is parallel to the propagation direction. Numerical results confirm these remarks for scattering by spheroids. On fixing εri, μri, εre, and μre, the effects of Γ and β on the total scattering efficiency were examined for a sphere. The total scattering efficiency does not depend on the polarization state of the incident plane wave, even when the exterior medium is not impedance-matched with the interior medium, and despite the presence of Γ and β. The total scattering efficiency when Γ is coparallel to the propagation direction can be either equal to, larger than, or smaller than when Γ is antiparallel or perpendicular to the propagation direction, depending on β and the electrical size of the sphere. It is found that parallel propagation of the incident plane wave with respect to Γ has a stronger influence than perpendicular propagation, regardless of β and the electrical size of the sphere. The effect of increasing/decreasing the magnitude of Γ can be envisioned only when its direction is parallel to the propagation direction.
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