This PDF file contains the front matter associated with SPIE Proceedings Volume 12064, including the Title Page, Copyright information, and Table of Contents

This paper studied the classification method of tea using portable Laser Induced Breakdown Spectroscopy (LIBS) system to distinguish different kinds of tea with similar appearances from each other. The basic classification algorithm was Random Forests, and an improved data processing method of spectroscopies was presented to increase the classification accuracy. The provenance of tea was set as the classification label because that tea produced in some specific areas may have higher economic value. Fifteen kinds of green tea were collected from the market, of which nine were produced in Guizhou Province and the other six were produced in six other provinces. The spectral integral normalization method, and element window filtering method were proposed to process spectral normalization and screening. The parameters of Random Forests algorithm were optimized to achieve both high accuracy and low time cost. Finally, the classification accuracy of green tea from Guizhou Province was 97.75%, and green tea from different provinces was 100%. The research results of this paper made it a bright future of LIBS in application of tea quality appraisal and other food industry.

Coal gangue is one of the main pollution sources in coal mining area, which can cause air, water, land and vegetation pollution. Therefore, in order to protect the ecological environment, coal gangue is usually buried underground. However, with the influence of soil erosion and other human factors, coal gangue from historical landfills gradually exposed to the surface, mixed with sand, and became the source of pollution again. In this study, through the analysis of X-ray powder diffraction and spectrum of coal gangue samples in Ordos coal mining area, it is found that the coal gangue in this area contains kaolinite. Kaolinite has unique spectral characteristics in the short wave infrared spectrum, which can be recognized by hyperspectral remote sensing. China launched the GF-5 satellite on May 9, 2018, equipped with a hyperspectral imager called the Advanced Hyperspectral Imager (AHSI). It has a spectral range of 400-2500 nm, with spectral resolutions of higher than 5 nm in the VNIR and 10 nm in the SWIR, respectively. On the basis of data processing, kaolinite information is extracted from hyperspectral reflectance data. Based on the field sample validation and image spectral analysis, it is concluded that hyperspectral data of GF-5 can effectively identify kaolinite information. At the same time, it is found that the spectrum of kaolinite in coal gangue is obviously different from that of kaolinite in clay mining, and they can be distinguished. Therefore, the distribution of coal gangue in mining area can be indicated by the identified kaolinite information.

To extended the effective focusing length (f) and narrowing lateral full width at half maxima (FWHM) of photonic nanojets (PNJs) formed by microlenses with wavelength-scale size, in this paper, we study focusing characteristics of dielectric hemisphere. Refractive index (RI) of hemisphere, radius of covering Au disks on flat-surface of hemisphere and immersed materials effect on focusing characteristics are studied. Simulation study show that hemisphere with radius 4.5 μm, shows narrower focusing beam waist, and shorter f when RI of hemisphere gets bigger. When RI reaches 2.5, lateral FWHM of PNJ and f are 177nm, 324nm, respectively, under illumination of a plane wave with a 365nm wavelength. Comparing with normal hemisphere, hemisphere (RI 1.52, radius 4.5μm and illumination wavelength 365nm) with Au disk covering its flat-surface center, shows obvious smaller FWHM of PNJ and shorter f (still longer than 2 μm). it is because that the engineered hemisphere is like a lens with high numerical aperture, and it only allows incident beam far away from the axis participate in the formation of PNJ. With increasing of Au disk radius, the equivalent numerical aperture gets bigger and thus FWHM of PNJ gets smaller. FWHM of PNJ small than half of illumination wavelength when radius of Au disk gets bigger than 1800nm. The length of PNJ in above study is short, less than 2μm. When the engineered hemisphere (RI 1.52, radius of hemisphere and Au disk 4.5μm and 1800nm, respectively) is immersed in water, MgF2, et al, the f and L get longer than 11μm, 5μm, respectively. Although lateral FWHM of PNJ at this time is bigger than 400nm, it can be narrowed by replacing it with bigger Au disk, optimizing immersed material, et al. Due to low manufacture cost of these hemisphere lenses and lenses array, we believe they have potential in near-field and far-field application with resolution small than 0.5λ.

The digital micromirror devices (DMD), as binary-coded masks, is an essential optical component in the coded aperture snapshot spectral imaging system (CASSI). However, DMD operating in MWIR or LWIR band usually introduces serious stray radiation by its diffraction effect, resulting in non-uniform images received by the CASSI. In this paper, we propose a new relative radiometric correction method for the DMD based CASSI in MWIR band. The method integrates a new coding method of CASSI and the traditional multipoint calibration method, and it can well suppress the nonuniformity noise of the infrared focal plane array. The working principle of the DMD based CASSI in MWIR band is introduced, then we design a new Hadamard coding mask, and investigate the corresponding decoding method. The mathematical mode of relative radiometric correction is established, and the relative radiometric calibration experiment is conducted to illustrate our method in detail. The experiment results indicate that the uniformity of the IR image at different temperatures corrected by the proposed algorithm is very good, and the temporal variation non-uniformity noise of the infrared focal plane array can be effectively suppressed.

Soil is an important link in the process of maintaining ecological balance, which is in the central position of connecting the organic and inorganic world in nature. As an important part of soil, mineral composition not only affects its physical and chemical properties, but also plays an important role in the adsorption and migration of heavy metals and organic pollutants in the ecological environment.In this paper, using the ZY-1-02D satellite hyperspectral data, combined with the USGS standard spectral library, analyze the overall spectral shape and local feature positions of soil mineral spectra.The method of combining spectral feature enhancement matching degree and feature parameter information extraction is used to extract typical minerals such as montmorillonite, kaolinite, calcite, dolomite, mica, hematite, and limonite in bare soil and invert its relative content,obtained the spatial distribution status and distribution characteristics of different soil minerals,it can provide theoretical basis for subsequent research on soil classification, soil physical and chemical parameter prediction, and provide technical support for soil fine mapping, utilization and protection of soil and mineral resources.

Terahertz reflectance spectrum is widely used in material thickness measurement, material composition detection and other aspects. However, the reflection wave is easily affected by the surface roughness produced in the process of material processing, resulting in noise and measurement error. In this paper, the terahertz reflection model of three-layer medium is derived, and the relationship between smooth surface and rough surface is established by Kirchhoff approximation theory. Secondly, the terahertz reflection spectrum and frequency spectrum of aloe emodin were measured by THz-TDS(terahertz-time domain spectral system). By introducing controllable roughness surface with sandpaper of different specifications, the reflection spectrum of roughness of each specification surface was measured, the reflectance corresponding to different frequencies was calculated, and the reflection spectrum of smooth surface was compared and analyzed. The influence of these results on the ability of THz reflection spectrum to detect Chinese medicinal herbs was discussed. In addition, by introducing Kirchhoff approximation, the reflection spectrum relation model of rough surface and smooth surface is established to compensate the reflection spectrum of rough surface. It is found that the power of reflection spectrum can be improved to some extent and the influence of rough surface on reflection spectrum can be reduced.

Aiming at improving the accuracy of unmixing result, this paper proposes an unmixing model for hyperspectral imagery which utilize both spatial and spectral information. A spatial-spectral sparse constraint unmixing algorithm based on Graph Laplacian (called SSGL) is introduced. Firstly, the lost function of SSGL is constructed. The model is improved with the spatial-spectral information of imagery. And then, a Graph Fourier Transform is applied to construct a weighted map for spectral information. After that, a symmetrical normalization Graph Laplacian Matrix is constructed with the aforementioned weighted map. This process constructs a new unmixing model for hyperspectral imagery based on Graph Laplacian. The spatial and spectral information of hyperspectral imagery are jointed together through Graph Laplacian Matrix. Before constructing the Graph Laplacian Matrix, a weight map is calculated uses Cauchy function. Normalization for Graph Laplacian Matrix is acted to eliminate the problem of image scale inconsistency. It makes principal component analysis and standardization of the distance between each node of the weight map, and obtains a more accurate weight map, which further improves the accuracy of unmixing. Secondly, the sparse abundance and endmember constraint is drawn into the unmixing model. Lastly, the iteration termination condition is given to the model. Endmember matrix and abundance matrix are obtained form the iteration process. The result demonstrates that the proposed SSGL unmixing algorithm shows better performance than the other two methods. And, regularization factor actually effects the unmixing result.

As an important part of the atmospheric environment, aerosols play a critical role in the study of the relationship between light and radiation. However, due to the complex spatiotemporal distribution of aerosols, it is much difficult to measure their microphysical properties and to determine their optical properties in coastal areas. In this paper, basic meteorological elements (e.g., wind speed, temperature, humidity) are simulated with the numerical weather forecasting (WRF) model. Then, the coastal aerosol model (CAM) together with the observation data is used to simulate the aerosol particle size distribution (APSD) and extinction coefficient for the coastal environment of Qingdao. Finally, data measured by the automatic weather station and particle counter in the coastal area are compared to their corresponding simulations. According to the comparisons results, temperature simulations were higher from an overall perspective (<2°C) with the correlation coefficient larger than 0.96; humidity simulations were comparatively lower on the 11th and 12th day (<10%) than those onthe 13th day (<20%), but the correlation coefficient was still larger than 0.8. With the meterological parameters simulations, the CAM model was used to predict the APSDs. It is founded that simulations for large particles are generally larger, while those for giant particles are generally smaller, but the simulated temperature, humidity, APSD and extinction coefficient are very consistent with their corresponding measurements. The method established in this paper is promising for the simulation and forecast of both the meteorological elements and aerosol microphysical properties.

The detection method based on FBG sensor network can be used for three-dimensional shape sensing of flexible snake shaped instruments. The main goal of this paper is to design a packaging process of miniature shape sensor which can be integrated into flexible medical instruments. In this paper, a novel fiber Bragg grating (FBG) sensor (diameter 1mm, length 260mm) is proposed to measure the shape of flexible robot. The sensor uses four evenly distributed fiber arrays, each of fiber contains three FBG nodes to obtain discrete curvature for shape sensing. First, the sensor packaging positioning device, the optical fiber positioning device, the glue injection method, and the glue type and packaging process of the sensor package are all improved to not only reduce the diameter of the shape sensor but also ensure the success rate of the sensor package and the accuracy of the package positioning. Secondly, the sensor network is designed, and encapsulated by the new encapsulation method. The packaged sensor has six measuring points. Finally, an experimental platform is established to experiment verification. The experimental results of shape reconstruction show that the measurement accuracy of the sensor is about 2.92%, which verifies the practicability of the sensor and the feasibility of the proposed packaging method.

The chromatic confocal technology (CCT) has ultra-high distance measurement resolution and the characteristics of multi-surface tomography. It is merely widely used to measure the thickness of uniform materials currently. As a typical inhomogeneous material, the iso-refractive index surface of the radial GRIN lens is a cylindrical surface with central axis symmetry. The radial GRIN lens is an important optical element in the field of micro integrated optical instruments, such as optical fiber sensing, optical communication, etc. High precision thickness measurement parameters help to guide the accurate application of the GRIN lens and control the performance of related ultra-precision optical instruments. To measure the thickness of the radial GRIN lens with a single probe by the advantage of the CCT technology in measuring tiny distances. In addition, the placement tilt of the GRIN lens during the measurement would change the incident position of the probe light entering the lens to change the propagation path of the light and inevitably affect the accuracy of thickness measurement. The influence of the GRIN lens placement tilt on thickness measurement is studied theoretically. The thickness measurement error caused by the inclination of the GRIN lens and its axial measurement position is simulated and analyzed. The research results have significance for optimizing the system structure and further improving the system performance for the application of the CCT in measuring non-homogeneous materials or optical thin film.

Liquid crystal tunable filter utilizes the electrically controlled birefringence effect of liquid crystal material to achieve rapid tuning of the central wavelength of the transmission spectrum. In this paper, we propose a fan Solc liquid crystal tunable filter with 8-stage structure, and the thickness of the nematic liquid crystal material in each liquid crystal cell is 3 μm. We compile a program according to Jones matrix calculation method to simulate and analyze the 8-stage Solc liquid crystal tunable filter. It can be clearly derived from the simulation results that this liquid crystal tunable filter can freely tune the center wavelength of the transmitted light in the spectral range of 400 nm to 800 nm. When the transmission peaks of the liquid crystal tunable filter are at 450 nm, 540 nm, 630 nm, and 750 nm, the full width at half maximum of the transmission spectrum are 45 nm, 54 nm, 63 nm, and 75 nm, respectively. What’s more, when the thickness of the liquid crystal material decreases from 10 μm to 6μm, the free spectral range of the 8-stage Solc liquid crystal tunable filter increases. We also performed a simulation experiment on 4, 8, 12 and 16-stage fan Solc liquid crystal tunable filters.The thickness of the liquid crystal material in these Solc-type liquid crystal tunable filters is still 3 μm. As the the number of stages of liquid crystal tunable filters increases, the full width at half maximum decreases gradually and is approximately inversely proportional.

This paper introduces the optical design method of an IMS prototype and proposes an entire optical system optimization approach. The final performance evaluation reveals that the optimized system could meet the requirements. The spectral range of the prototype is designed to be from 450 nm to 700 nm, containing 31 bands. The spectral resolution at the central wavelength is about 8 nm. The field angle (2ω) is 1.86 deg, and the spatial angle resolution (ωΔ) is designed to be 0.013 deg.

Different from the principal component analysis (PCA), non-negative matrix factorization (NMF) can provide more direct interpretation owning to the non-subtractive combinations of non-negative basis vectors, and many practical problems also require non-negative basis vectors rather than the orthogonal vectors with alternating positive and negative. In this study, we develop a hyperspectral surface reflectance reconstruction method based on NMF and multispectral results in several wavelength bands. In order to test our spectral reconstruction method, the spectral datasets of typical surface types are extracted from the spectral library of John Hopkins University (JHU), which include the soil, vegetation, manmade materials, sedimentary fine and coarse rock. The prior surface reflectance or emissivity results are selected from only four wavelength bands (2.13, 3.75, 3.96, 4.05 μm) from shortwave infrared to Mid-infrared, which can be easily obtained from the surface product of Moderate-resolution Imaging Spectroradiometer (MODIS). Based on the JHU spectral dataset and NMF, the hyperspectral surface reflectance in the spectral range of 2-5μm with the step of 25 nm can be reconstructed consistently. In addition, the hyperspectral reconstruction effects by NMF are quantitatively investigated, in which the root mean square error and the mean absolute error is about 0.016 and 0.01, respectively.

Hyperspectral imager is easily affected by noise in the process of imaging, so it is difficult to evaluate the noise in it. It is difficult to obtain accurate image noise values by existing technical methods, and it is also a problem to correct different environmental light sources.In this paper, by comparing the reflectivity inversion results obtained from the inversion of different number of reflectance plates.Inversion method based on the double reflectance plate is the best choice finally. The mean square error of the reflectance spectrum and the calibration spectrum obtained from the inversion in the band of 500~900nm is less than 0.0001, which effectively corrects the radiation error in the image.Based on PCA and SVM algorithm to build the grain heavy hyperspectral classification model.The improvement of the total accuracy and test accuracy of the inversion model based on double reflectance plate is better than several other inversion methods.Compared with single reflectivity inversion reflectance spectra, inversion method based on the double reflectance plate build hyperspectral database after training to obtain a set of test precision of 4.409%, total classification accuracy of 3.104%.

Hazardous chemicals leakage and explosions issues severely threaten public safety and social development. In recent years, Raman spectroscopy has the advantages of multi-component detection, with a simple device and nondestructive detection, and it has been applied in the detection of hazardous chemicals. There are many advantages of excitation UV compared to visible or near-IR counterparts: 1) Solar blind detection enabling standoff operation in full daylight; 2) Fluorescence-free Raman enabling enhanced detection and identification of target materials without interference; 3) Eye retina safe. Based on the above analysis, a compact proximal UV-Raman spectroscopy setup was built in the laboratory. A 266nm UV laser with a high repetition rate was used as the light source in the setup, which has many advantages, such as a cramped structure with an air-cooled device and low energy. An independently built Galileo transmission telescope was be used to collect signals in the setup. In addition, a customized UV high-sensitivity fiber spectrometer was used to detect the Raman signals. Typical hazardous chemicals (dichloromethane, anhydrous ethanol, potassium nitrate) were detected at 1000mm using the built setup. The experimental results indicated that clear Raman signals of the hazardous chemicals could be detected when the exposure time of the spectrometer was only 15ms (satisfied the conditions of human eyes safety). A new eye-safe UVRaman spectroscopy technology in this paper provides method support for rapidly detecting hazardous chemicals in the future.

In order to overcome the problems of low diffraction efficiency, large aberrations and stray light of traditional ruled gratings in reflective Raman spectrometers, combined with the characteristics of the Raman signals of lunar surface minerals, a volume phase holographic (VPH) grating Raman spectrometer system for lunar surface detection was designed. The spectral range of the spectrometer is 140~3073cm^-1, and the field of view is 3°. According to the Kogelnik coupled wave theory, the diffractive efficiency of the designed VPH grating is more than 95% at the central wavelength, and the average efficiency is more than 80% in the whole spectral range. After optimizing with zemax, the MTF of the entire spectrometer system at the Nyquist frequency is greater than 0.45, and a spectral resolution of 10 cm^-1 can be achieved.

Atmospheric correction is the basis for quantitative analysis of satellite remote sensing images, such as monitoring land surface changes. However, precise atmospheric correction is still challenging. Landsat 8 is a satellite used for surface monitoring launched by the United States National Aeronautics and Space Administration (NASA) in 2013, with good spatial resolution. Rich spectral information. In this paper, an improved dense dark vegetation(DDV)aerosol retrieval algorithm is developed, and the retrieved AOD map will be used to process the aerosol impact factor of remote sensing images. Atmospheric correction is performed based on a lookup table generated by the 6SV model. Validation with the Land Surface Reflectance Code (LaSRC) algorithm produced atmospheric correction images, correction images of the paper algorithm showed a good agreement with high correlation(Correlation R exceeds 95%). Meanwhile, a reliable software prototype system for processing atmospheric correction on Landsat 8 OLI images was developed. This system is based on C++ language and can perform atmospheric correction automatically, low-latency, and accuracy. The data products corrected by the software prototype are helpful for the widespread application of remote sensing data in emergency response, environmental monitoring, and national defense.

In order to study the optical properties of marine aerosols, the optical thickness, wavelength index, spectral distribution, refractive index, single scattering albedo and elevation of aerosol particles were measured by means of solar radiometer, micro pulse lidar and automatic weather station in Qingdao, South China Sea, East China Sea and South China Sea from July to November 2019. The results show that the aerosol optical thickness measured by the shipborne data is smaller than that measured by Qingdao and islands, and the aerosol elevation range is about 0.4-0.7, The diurnal variation is relatively stable, and the distribution of aerosol colloidal product spectrum in the offshore and the open sea has the same change trend. The radius of the coarse mode is about 2.4 μm-3.6 μ M. compared with other data, the real part of the refractive index is larger, the imaginary part is smaller, and the difference in the long wave band is more obvious. The single scattering albedo basically does not change with the wavelength.

Based on the extended Huygens-Fresnel principle, an analytical expression for the cross-spectral density for optical coherence lattices in oceanic turbulence is derived. We study the properties of Ghost imaging (GI) with partially coherent beam in oceanic turbulence. We have discussed the effect of turbulence strength and other parameters on GI. As the turbulence strength or transmission distance increase, it will lead to the degradation of the spatial resolution, and the quality of GI will become worse.

Aiming at the development trend of miniaturization and high resolution of spectrometers, a cross-type Czerny-Turner structure is adopted, and a small spectrometer with simple structure and astigmatism is designed. The principles and correction methods of various aberrations of the cross-type spectrometer are analyzed, the cylindrical mirror is used to correct the astigmatism of the system, and the theoretical equations are derived. The optical design software Zemax is used to optimize the design of the optical system with a wavelength range of 300nm-900nm. The results show that the system has a compact structure and a size that meets the requirements of miniaturization. At the same time, the cylindrical mirror can effectively reduce astigmatism, and the center wavelength resolution can reach 0.5nm, the edge wavelength resolution reaches 1nm.

Michelson interferometer is one of the core technologies of time-modulated Fourier transform infrared spectrometer. And the control effect of the interferometer moving mirror has a very important influence on the instrument performance. In this paper, based on the double pendulum interferometer, the control technology of its moving mirror is studied. According to the basic principle of double pendulum interferometer, the general scheme of hardware system design is proposed. And under the guidance of the overall scheme, the modular design of the control system is carried out. There are mainly laser detection modules, main control module, motor drive module, etc. The moving mirror control algorithm is designed in the lower computer software, and the speed of the moving mirror is controlled using the compound control algorithm formed by the combination of incremental PID control and feed-forward control. The control effect of the moving mirror is improved. The upper computer software uses LabVIEW to design and test the control effect of the control system. The test results show that the relative speed error of the moving mirror based on the double pendulum interferometer is better than ±0.35%, and the stability is high, which can meet the requirements of the interference system index.

The propagation characteristics, including beam propagation factor (i.e., M²-factor) and characteristic distances, of truncated Airy (TA) beams is studied in atmospheric turbulence. Based on the extended Huygens-Fresnel principle and the second moments of the Wigner distribution function (WDF), the analytical expressions of the M²-factor of the TA beam in a turbulent atmosphere are derived. By using Andrews spectrum as the atmospheric turbulence model, numerical examples of M²-factor, relative M²-factor, turbulent Rayleigh distance and turbulence distance are given. The results show that the M²-factor, which depends on the truncation factor and the initial first lobe width, decreases with the decrease of the structure constant of turbulence, and with the increase of the inner scale of turbulence. The relative M²-factor decreases with decreasing structure constant of turbulence and truncation factor and with increasing the inner scale. There exists an optimum initial first lobe width which corresponds the minimum of the M^2-factor. The turbulent Rayleigh range increases with decreasing truncation factor and inner scale. The turbulence distance increases with decreasing truncation factor and increasing inner scale.

Fourier Transform Infrared(FTIR) spectroscopy has many advantages, such as high light flux, high resolution, high sensitivity and so on, and has been widely used in the field of industrial gas monitoring. Unit detector is used by traditional Fourier transform infrared spectrometer, which needs scanning platform to assist imaging, and the structure of spectrometer is complex. In order to satisfy the application of small area array detector spectrometer, this paper is based on the small area array HgCdTe photoconductive long wave infrared detector and double pendulum interferometer. The working principle and signal characteristics of the spectrometer are analyzed, and a method of multi-channel weak interference signal detection circuit for 4×4 small area array detector is proposed, and the method is simulated and verified by experiments. Using Multisim software to simulate the circuit, the results show that the circuit has good band-pass characteristics and can achieve distortion-free signal amplification. The collected interference data are analyzed by using MATLAB software, and the interference data are subjected to spectral restoration and spectral calibration. The results show that the amplitude consistency and phase consistency of the interference data are good, and the spectral waveforms of each channel are close to each other, which can well distinguish and measure the long wave characteristic peaks in the region.

X-ray absorption fine structure (XAFS) is an important tool for materials information of atoms with bond length, coordination numbers and electronic state. Most of the related research has been performed at the synchrotron radiation facility for past decades. The development of conventional X-ray source and bent crystal analyzer makes it possible to conduct XAFS experiment in the laboratory. We developed a laboratory X-ray absorption spectrometer. It includes an conventional X-ray source, a Johann-type spherically bent crystal analyzer, precision Rowland circle scanning mechanism, and a silicon drift detector. The spectrometer is designed for both the X-ray absorption near-edge structure (XANES) and the extended X-ray absorption fine structure (EXAFS) analysis. The spectrometer covers the photon energy range of 8.9 – 9.6 keV and the energy resolution is about 1.2 – 3.5 eV with W anode source (spot size 0.4 mm) and Ge(800) crystal. The absorption spectrum of a copper foil with thickness of 10 μm is measured. The result is similar to that conducted at the synchrotron radiation facility.

Improvised explosive devices (IED) and homemade explosives (HMEs) have become the preferred choice for terrorists and insurgents. It’s a challenge to develop the techniques to detect explosive hazards at standoff distances. In this paper, a standoff UV Raman spectrum detection system for explosive detection was developed, which can realize 2-10m Raman spectrum detection of solid, solution and trace potassium nitrate samples. The relationship between Raman signal intensity (RSI) and pulse energy, detection distance and sample concentration was studied. The experimental results show that the RSI is approximately proportional to the pluse energy and contains nonlinear terms. It has an inverse square relationship with the detection distance and a linear relationship with the sample concentration. The concentration of solution and trace potassium nitrate samples of were successfully predicted at 2m distance, and the root mean square error of prediction (RMSEP) was 11.7 and 6.1, respectively.A simple and effective method for preparing trace potassium nitrate is presented.

Multi-frame blind deconvolution (MFBD) is a commonly used method of image post-processing technique to restore high-resolution image from the image observed through ground-based telescopes. During the restoration process, the frequencies with low signal-to-noise (SNR) ratio in the spectrum of the image which are called “spectrum holes” can easily lead to noise amplification effect. Hence there is a filtering idea by calculating the “spectrum holes” to impose the frequency domain constraint in MFBD. Hundreds of images observed through ground-based telescopes are often needed to obtain high quality images, which makes a considerable cost of computation. We discard the information in the images that have not been selected to improve the speed of the process. In this paper, we use the compact blind deconvolution algorithm (CMFBD). A small number of images with better quality as “control frames” is firstly selected to run the traditional MFBD, under such treatment, we can use relative less time to quickly obtain the PSFs corresponding to the “control frames”, and then, the PSFs corresponding to the “non-control frames” is obtained through the “consistency” principle which we assume object is the same in each frame. In CMFBD the non-selected data frames is used to provide an additional constraint on the PSF estimates for the selected data frames.

When the laser passes through the haze atmosphere, the laser interacts with the haze particles and scatters. The scattered light will take away the energy of the laser beam. At the same time, the scattered light maps the physical characteristics of the haze particles, such as the particle size parameters of the haze particles. Polarization information such as shape model, scale distribution, etc. Comprehensive analysis of the light intensity information, polarization information and spectral information of the scattered light and the main beam can not only draw the light scattering law of the haze particles, but also reflect the physical characteristics of the haze particles, so as to better improve the optics. The accuracy of the system's inspection of haze particles, so the use of light beams to study the relevant parameters of haze particles is becoming more and more important. This article first analyzes the physical parameters of the haze particles, and elaborates on the scattering theory of the laser beam by the haze example. In the artificially simulated haze environment, by changing the haze concentration and measuring distance, the attenuation change of the light intensity is measured. According to the Mie scattering theoryi, the direct-view and non-direct-view single-scattering models of haze spherical particles analyze the corresponding parameter relationships.

Defense and security applications often require definitive and non-destructive testing or identification of samples to enable testers to make effective decisions and preserve potential evidence. Raman spectroscopy has consistently demonstrated its effectiveness as an analytical technique in defense research and applications without interfering with sample integrity. Aiming at the fact that Raman spectroscopy is limited to detect sample composition within the near surface layer or transparent medium, Rutherford Appleton Laboratory proposed the spatial offset Raman spectroscopy. This technique can effectively suppress the powerful Raman and fluorescent signal interference from the surface substance, and realize the composition detection under the opaque diffuse scattering medium material of a few mm or cm. In this paper, we have detected and analyzed the spatially offset Raman spectroscopy of sodium nitrate, sodium sulphate and their mixture powder.

The laser electromagnetic hybrid propulsion is a propulsion method that generates thrust through the synergistic action of laser ablation propulsion and electromagnetic propulsion. Laser ablation propulsion and electromagnetic propulsion complement each other to produce better thrust performance. In this paper, the emission spectra of pulsed electromagnetic propulsion (PEP) and laser assisted pulsed electromagnetic propulsion (LAPEP) are studied, and the composition, temperature and density of plasma plume are calculated. The evolution of plasma plumes of laser electromagnetic combined propulsion (LEHP) in the initial stage of formation and in the discharge chamber are studied by using a high speed camera. The results show that charged particles in PEP and LAPEP plumes are mainly C+, F+, C++ and F, among which C+ has the highest luminescence intensity of plasma. Calculated with the C+ spectral line intensity of plasma and the multi-spectral method, the electron temperature of PEP and LAPEP is about 12300K, and the electron density is about 1.2×10²⁶m^-3, which the electron temperature and density of LAPEP are slightly higher than those of PEP. In addition, the plasma evolution law and the discharge characteristics of LEHP are different from that of PEP. The plasma evolution process of PEP is continuous and regular, and the evolution process of LEHP is irregular.

The beam wander properties of electromagnetic Gaussian Schell-model (EGSM) beam propagating in atmospheric turbulence are investigated based on the extended Huygens–Fresnel principle, the second-order moments of the Wigner distribution function (WDF) and the Andrews beam wander theory. The simplified integral formulae for the root-mean-square (rms) beam wander and the relative beam wander of EGSM beams in turbulence have been derived. Our results indicate that in a strong turbulence, the rms beam wander increases obviously with increasing inner scale, and the influence of inner scale of turbulence on the rms beam wander can not be ignored in strong turbulence. The evolution behaviors of the rms beam wander and relative beam wander in atmospheric turbulence are quite different which depend on the initial beam width, the transverse coherence width, the inner and outer scales of turbulence. Both the rms beam wander and relative beam wander can be effectively reduced by increasing the initial beam width and decreasing the transverse coherence width.

Due to the rapid advancement of informationization process, a large number of product characteristic data have been accumulated in the process of testing, and the quantity of product characteristic data is increasing exponentially. The traditional characteristic data often presents the data content in the way of query, etc., and fails to display the data existing in the target rapidly and integrally. This paper designs an anchor point positioning based on the text through interactive method, used in a web page display product feature information in the form of text, use convenient interaction provides users with convenient, fast text browsing experience, elaborated the method of technical implementation ways, finally proved that the method enables users more intuitive preview, Improve the efficiency of viewing and analyzing data.

Laser-induced breakdown spectroscopy (LIBS) is an atomic emission spectroscopy, which has been used to analyze the composition of materials in many areas. In order to improve the detection sensitivity of LIBS, many methods have been proposed to improve the spectral intensity of LIBS. It has been proved that the intensity of femtosecond LIBS spectra of metal can be enhanced by using circularly polarized laser as excitation source. In this paper, the effect of polarization of laser beam on emission intensity of nanosecond LIBS was investigated. The spectral intensity of nanosecond LIBS of brass was enhanced with circularly polarized laser excited.

Space objects images taken through large ground-based telescopes usually suffer from a degradation due to atmospheric turbulence, In order to reduce the cost of Charge-coupled Device (CCD) and improve the image signal-tonoise ratio, ground-based telescopes are usually designed with down-sampling, the observed image is blurry and aliased. We present a Super-Resolution (SR) algorithm to restore under-sampled image sequences with randomly varying blur, the algorithm significantly improves the quality and resolution of space object images degraded by atmospheric turbulence, it is a unifying framework that simultaneously performs Multi-frame Blind Deconvolution (MFBD) and SR in a maximum a posteriori (MAP) framework. The object and the Point Spread Function (PSF) are estimated by minimizing a cost function coming from the MAP criteria, the Total Variation (TV) regularization is imposed on the object estimation, TV regularization is remarkably effective to suppress the noise and to preserve the sharp edges in the image. We use the conjugate gradient method for the minimization for its fast convergence. Encouraging simulation results demonstrate that the restored image produced by this algorithm often have better quality than MFBD.