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Clouds lead to missing or distorted land-related information in impacted areas in optical remote sensing images. Cloud masking, which labels cloud-contaminated pixels, forms the basis for subsequen...

Optical liquids are ideal materials for designing apochromatic lens due to their lower refractive index and higher Abbe numbers than those of the ordinary optical glasses. Based on the Buchdahl dispersion formula, the dispersion coefficient diagram of liquids and glasses is established. The liquid-glass combination lens(LGCL) with small secondary spectrum is obtained by calculating the combination structure with low dispersion liquid and glasses. The initial optical structure of the liquid-glass apochromatic lens(LGAL) can be obtained by replacing two glass lenses in an initial optical system with the LGCL. Using the multi-configuration optimization of ZEMAX, the liquid-glass achromatic zoom lens (LGAZL) can be designed by optimizing the LGAL. The LGAZL has an objective field of view ϕ63 mm–ϕ57 mm, an image field of view 8 mm, a working distance 240 mm and the zoom range of focal length 75–85 mm. The chromatic aberration and the secondary spectrum of the LGAZL are all less than 3 μm in the whole zoom range.

The present work shows implementation of SLAM for mapping and navigation in indoor environment under robot operating system ROS, using differential drive robot provided by laser scan. Mapping process is done by using ROS packages based on extended kalman EKF filter algorithm, whereas localization is done by using packages based on adaptive Monte Carlo localization AMCL, navigation is performed by ROS built functions. Paper also will give concrete intuition about using EKF to accomplish SLAM, and shows how the results diverge in case of not using SALM algorithm.

Precise machine vision detection for a large object at a finite working distance (WD) requires that the lens has a high resolution for a large field of view (FOV). In this case, the effect of a secondary spectrum on image quality is not negligible. According to the detection requirements, a high resolution apochromatic objective is designed and analyzed. The initial optical structure (IOS) is combined with three segments. Next, the secondary spectrum of the IOS is corrected by replacing glasses using the dispersion vector analysis method based on the Buchdahl dispersion equation. Other aberrations are optimized by the commercial optical design software ZEMAX by properly choosing the optimization function operands. The optimized optical structure (OOS) has an f-number (F/#) of 3.08, a FOV of φ60 mm, a WD of 240 mm, and a modulated transfer function (MTF) of all fields of more than 0.1 at 320 cycles/mm. The design requirements for a nonfluorite material apochromatic objective lens with a large field and high definition for machine vision detection have been achieved.

Nb 2 O 5 nanowires with controllable carbon coating thickness were prepared by plasma enhanced chemical vapour deposition. These hybrid nanowires were found to be efficient field emitters where the turn-on and threshold fields decreased with increasing carbon coating thickness. Notably, high current density was obtained from these hybrid nanowires (a maximum of ∼59 mA/cm 2 at 11 V/μm) which was an order of magnitude higher than pristine Nb 2 O 5 nanowires. The emission sites were distributed uniformly and current stability tests showed a stable emission current density with

The secondary electron emission (SEE) yield of heterostructures of zinc oxide (ZnO) nanoneedles coaxially coated with aluminum nitride (AlN) or gallium nitride (GaN) has been studied using ion and X-ray beams. This paper describes experiments performed with ions (2 MeV protons and 3.6 MeV/nucleon carbon beams) and photons (synchrotron radiation at ≈1 keV). The SEE yield of the heterostructures is enhanced significantly by the intrinsic nanostructure of the ZnO nanoneedle templates as compared to the AlN and GaN thin films on silicon (Si) substrates [T.J. Vink, R.G.F.A. Verbeek, V. Elsbergen, P.K. Bachmann, Appl. Phys. Lett. 83 (2003) 2285]. One of the mechanisms responsible for SEE yield enhancement can be attributed to the larger area of the nanostructured surface.

A second parallel CCD (CMOS) imaging system for an telescope objective with the fixed D/f' is proposed in detail. As a direct imaging system that the CCD target surface coincides with the imaging surface of the telescope objective, it shows the outstanding performance of more than doubled resolution compared with the ordinary telescope objective under the same D/f'. Based on the discussions about the second parallel optical path telescope system, three design examples are compared and analyzed. The relation between the optical properties of image field and the optical elements of the second parallel path is clarified, which provides an operable method for readers. This practice has proved the outstanding performance of the new telescope objective photoelectronic imaging system which indicates potential applications in broad scientific and industrial prospects.

Considering constructional algorithms for solving Traveling Salesman Problem (TSP), the solution process of Nearest Neighbor (NN) is the simplest one, but its performance is the worst. This paper proposes an improved NN algorithm for solving TSP in Euclidean Plane. Firstly, the algorithm searches four corner-nodes from all nodes, and gets a simple tour which only includes four corner-nodes, obtains four segments and their start nodes and end nodes, respectively. Then, each segment starts from current corner-node, and the algorithm selects a node as next target node from its multi-orientation nearest neighbor nodes, considering their distance and orientation comprehensively, and searching process repeatedly until each segment arrives at their end nodes. Furthermore, the algorithm inserts those rest nodes into a certain segment. At last, the algorithm connects four segments from stem to stern to form the final tour. Experimental results indicate that the proposed algorithm greatly improves the result of NN algorithm.

The secondary electron emission (SEE) yield of heterostructures of ZnO nanoneedles coaxially coated with AlN or GaN has been studied for the first time using electron, ion, and X‐ray beams. The SEE yield of the heterostructures is enhanced significantly by the intrinsic nanostructure of the ZnO nanoneedle templates as compared to the AlN and GaN thin films on Si substrates. These findings open up a way to develop new universal highly efficient radiation detectors based on the SEE principle by incorporating these one‐dimensional (1D) nanostructures as a material of choice.