Development of an Optical System Based on Spectral Imaging Used for a Slug Control Robot

The state-of-the-art technique to control slug pests in agriculture is the spreading of slug pellets. This method has some downsides, because slug pellets also harm beneficials and often fail because their efficiency depends on the prevailing weather conditions. This study is part of a research project which is developing a pest control robot to monitor the field, detect slugs, and eliminate them. Robots represent a promising alternative to slug pellets. They work independent of weather conditions and can distinguish between pests and beneficials. As a prerequisite, a robot must be able to reliably identify slugs irrespective of the characteristics of the surrounding conditions. In this context, the utilization of computer vision and image analysis methods are challenging, because slugs look very similar to the soil, particularly in color images. Therefore, the goal of this study was to develop an optical filter-based system that distinguishes between slugs and soil. In this context, the spectral characteristics of both slugs and soil in the visible and visible near-infrared (VNIR) wavebands were measured. Conspicuous maxima followed by conspicuous local minima were found for the reflection spectra of slugs in the near infrared range from 850 nm to 990 nm]. Thus, this enabled differentiation between slugs and soils; soils showed a monotonic increase in the intensity of the relative reflection for this wavelength. The extrema determined in the reflection spectra of slugs were used to develop and set up a slug detector device consisting of a monochromatic camera, a filter changer and two narrow bandpass filters with nominal wavelengths of 925 nm and 975 nm. The developed optical system takes two photographs of the target area at night. By subtracting the pixel values of the images, the slugs are highlighted, and the soil is removed in the image due to the properties of the reflection spectra of soils and slugs. In the resulting image, the pixels of slugs were, on average, 12.4 times brighter than pixels of soil. This enabled the detection of slugs by a threshold method.

Оптические свойства кремниевых нанопилларов со встроенным вертикальным p-n-переходом

Resonance reflection of light from the ordered arrays of silicon nanopillars (Si NP) was investigated. The height of Si NP was 450 nm. The effect of Si NP oxidation in concentrated nitric acid on the position of resonances in reflection spectra was studied. A weak influence of the additional polymeric coating on the characteristics of reflection from the structures was proven. It is established on the basis of the results of experimental investigation and direct numerical modeling by means of three-dimensional finite difference time domain algorithm (3D FDTD) that the dependence of the resonant wavelength for Si NP on the diameter of Si NP is a linear function with nonzero displacement depending on the pitch.

Arrangement Of Silver Nanostructures on Permeable Silicon and Examination of Their Optical Properties

Considers of nanostructures created beneath different modes of submersion testimony of silver on permeable silicon (PS) for their utility as dynamic substrates in monster Raman spectroscopy (SRS) are displayed. PS was shaped by anodizing monocrystalline silicon in an aqueous-alcoholic arrangement of hydrofluoric corrosive. The reflection spectra of the gotten silver nanostructures on PC have been examined. It is uncovered that to form ideal conditions for SERS spectroscopy utilizing silver nanostructures on PC, it is vital to utilize an energizing laser with a wavelength of 400–450 nm.

Peculiarities of specular infrared reflection spectra of ZnO-based ceramics

Undoped and Mn-doped ZnO ceramics were theoretically and experimentally investigated using specular infrared reflection method. It was shown that infrared reflection spectra can be modeled using the parameters explored for ZnO single crystals. For ceramic samples, it was shown that ZnO grains with orientation of the C-axis along the normal to the electric field ( ) give the main contribution to IR reflection spectra. It has been ascertained that the surface roughness is manifested in these spectra mainly within the range 450…550 cm–1 giving negligible effect for the frequencies above longitudinal phonon frequency. This allowed the electrophysical parameters of ZnO crystallites to be evaluated. In the case of undoped ceramics, the obtained results were found to be consistent with the values of direct current measurements. This finding supports the utility of infrared spectroscopy for determination of the electrophysical parameters of polycrystalline ceramic materials. For Mn-doped ceramic samples, the conductivity value measured using the direct current method was found to be essentially lower than those determined from simulation of infrared reflection spectra. This phenomenon was explained by barrier formation at the grain boundaries in Mn-doped ZnO ceramics.

Ab initio calculation of the electronic structure of a solid solution of strontium-bismuth molybdat

Scheelite-like compounds based on SrMoO4 have been studied. Based on X–ray structural data, models of Sr1-3xBi2xMoO4 structures (x=0.2125) are constructed, at x≧0.175, a superstructural ordering is observed associated with the location of cationic vacancies. From the first principles, calculations of the density of states in the vicinity of the forbidden zone are performed. The calculated values of the band gap width were compared with the values obtained from the reflection spectra.

Spectral Fourier-microscopy of the periodic structures based on Ge2Sb2Te5

The method of spectral Fourier microscopy was used to study the reflection spectra with an angular resolution of submicron periodic gratings based on amorphous and crystalline Ge2Sb2Te5. The form of the dispersion curves of quasi-waveguide modes in the structures under study was established. The experimental data were compared with the calculations of dispersion curves in synthesized diffraction gratings. Reasonable agreement between theoretical and experimental data was obtained.

Modification of a silicon surface visible light reflectivity by the carbon nanofilm

Crystalline silicon substrate visible light reflectivity is finely modified by a discrete growth of carbon nanofilm (CNF) on it by nanosecond pulsed laser deposition (PLD) technique. It is established that 71 nm thick CNF effectively reduces the high reflection of the substrate on average to 5% in the visible light wave range. The exact values of the thickness and refractive index of the carbon nanofilm are also determined via an analysis of reflection spectra.