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[IEEE 2018 7th International Conference on Agro-geoinformatics (Agro-geoinformatics) - Hangzhou (2018.8.6-2018.8.9)] 2018 7th International Conference on Agro-geoinformatics (Agro-geoinformatics) - Monitoring of Rice Leaf Folder Damage Based on Remote Sensing Methods
摘要： Rice leaf folder (Cnaphalocrocis medinalis Guenée) is one of the most important pests that endanger rice development and yield, which has characteristics of large outbreak areas, high occurrence frequencies and heavy damages. At present, the monitoring methods of rice leaf folder damage is based on artificial investigation, which has the advantages of objective truth and high reliability, while there is a drawback of time-consuming, and it cannot used for a wide range of rice damage monitoring. An ASD (Analytical Spectral Devices, Inc.) Hand-held Spectroradiometer was used at jointing stage of rice. The results showed that, reflectance from rice canopy significantly decreased in the green (530-570 nm) and near infrared (700-1000 nm) regions, and significantly increased in the blue (450-520 nm) and red (580-700 nm) regions as the rice leaf folder population increased. Reflectance from rice canopy significantly decreased in the spectral regions from 737 to 1000 nm as the infestation scale of pest population increased, and the most correlation appeared at 941 nm. The more the numbers of rice leaf folder, the higher the changes of such characteristic parameters. The positive correlations were found between the damage of rice leaf folder and the discrepancy of characteristic parameters in these experimental fields. With China Remote Sensing career advancement, a large number of independent researches and development satellites have launched. Among a new generation of high-resolution satellites, GaoFen-1 (GF-1) stands out. It sets high spatial resolution (2 m-16 m), multi-spectral and high temporal resolution (4-day) with 60 km-800 km swath in a fusion technology with strategic significance. In order to explore the adaptability of Chinese GF-1 images in monitoring rice damage from rice leaf folder, nine rice fields were selected by damage severity in Xinghua City, Jiangsu Province at full heading stage in 2015, and the Ratio Vegetation Index (RVI), Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), 2-band Enhanced Vegetation Index (EVI2), Soil Adjusted Vegetation Index (SAVI), Optimized Soil Adjusted Vegetation Index (OSAVI) were used to characterize the occurrence of rice leaf folder damages, which were calculated from the satellite GF-1 retrieval data. A series of analyses were performed to disclose the relationship among these six indices and the severity of rice leaf folder. Quantitative correlation analyses showed that NDVI, EVI, EVI2, SAVI, OSAVI and leaf folding population had a highly significant correlation (P<0.01), and SAVI had a highest correlation of 0.94. While there was no significant correlation between RVI and leaf folding population. Therefore, it was feasible to using hyperspectral data and GF-1 satellite images to monitor and warn the outbreak and development of rice leaf folder, which provided a new possible method to monitor dynamically the damage of rice leaf folder.
关键词： pest population,spectral characteristics,rice leaf folder damage,GF-1 WFV image
更新于2025-09-23 15:23:52
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Sensitivity Analysis of Multifrequency MIMP SAR Data From Rice Paddies
摘要： The determination of the accurate composition ratio of scattering mechanisms (volume scattering, double-bounce scattering, and surface scattering) within a radar backscatter is essential to validate current polarimetric decomposition techniques. Multiincidence angle and multipolarimetric synthetic aperture radar (MIMP SAR) observations at the X- and L-bands were applied to rice paddies at late vegetative stage in Niigata City in Japan in 2014 and 2016, respectively. In this paper, multifrequency MIMP SAR analysis is introduced based on the observation results. The approach, combined with theoretical characterization of the data by a discrete scatterer model, showed that rice panicles affect the backscatter from rice paddies. Contrary to expectation, an effect of transmissivity by using different bands is not obvious. The similar level of copolarization (HH and VV) backscatter at X- and L-bands could be explained by the effective size of rice panicles. They are the most characteristic scatters in rice paddy field with respect to multiple frequency polarimetric sensing. In addition, HV shows a distinct sensitivity to the mean orientation angle and the size of panicles regardless of the wavelength. The mean orientation angle affects the polarimetric randomness under azimuthal symmetry, whereas the size of panicles directly affects the attenuation of the volume scattering from the grains. The multifrequency MIMP SAR analysis also indicated the importance of considering the backscatter and attenuation in the interpretation of the backscattering cross section from vegetated fields.
关键词： rice paddies.,multifrequency multiincidence angle and multipolarimetric synthetic aperture radar (MIMP SAR),Discrete scatterer model (DSM)
更新于2025-09-23 15:23:52
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Efficient method to calculate the optical quantities of multi-layer systems with randomly rough boundaries using the Rayleigh-Rice theory
摘要： An efficient and numerically stable method for calculating the optical quantities of multi-layer systems with slightly rough boundaries using the second order Rayleigh–Rice theory is developed. It is assumed that the mean planes of the boundaries are parallel and all the media forming the system are nonmagnetic, isotropic and homogeneous. The perturbation series is formulated using the four-dimensional formalism inspired by the Yeh matrix formalism, but the final result is written using the two-dimensional formalism which is more efficient for the numerical calculations. The final formulae, which are expressed using an arbitrary power spectral density function, include the mixing between the p and s polarizations occurring for anisotropic roughness. Although in the general case the calculation of optical quantities requires evaluation of double integrals, it is shown that for the power spectral density function given by the isotropic Gaussian function some integrals can be calculated analytically and only single integrals have to be evaluated numerically. The random roughness of boundaries is a defect that occurs frequently in practice, and it must be taken into account in the optical characterization and synthesis of thin film systems exhibiting this defect. The presented method is suitable for these purposes, since both of the mentioned applications require methods that are very fast.
关键词： multi-layer systems,optical quantities,Rayleigh–Rice theory,random boundary roughness
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Effect of the Double-Bounce Contribution in Polinsar-Based Height Estimates of Rice Crops Using Tandem-X Bistatic Data
摘要： In bistatic acquisitions the presence of a double-bounce contribution at the ground affects the interferometric coherence with a decorrelation factor which is usually overlooked in studies employing polarimetric SAR interferometry. The standard acquisition mode of TanDEM-X is bistatic, so the influence of this contribution in the estimation of scene parameters (ground topography and vegetation height) is studied here. The analysis is carried out both with simulations and real data acquired over rice fields during the science phase of TanDEM-X. Results show that the error in height and topography is small when incidence angle is below 30 degrees, but may become noticeable for shallower incidences.
关键词： vegetation,rice,Polarimetric SAR interferometry,bistatic radar,TanDEM-X
更新于2025-09-23 15:21:21
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The effect of hydrothermal conditions on photoluminescence properties of rice husk-derived silica-carbon quantum dots for methylene blue degradation
摘要： Carbon quantum dots (CQDs) have potential to replace metal-based quantum dots due to its low-toxicity. However, studies on CQDs preparation were dominated by synthetic carbon precursors. Switching the precursors into natural ingredient is preferred since they are highly abundant and low-cost. In this study, composite of silica-carbon quantum dots (Si-CQDs) were fabricated from rice husk through a hydrothermal process. Si-CQDs with diverse properties are beneficial for its application in the future; therefore, the variation of hydrothermal conditions (i.e., temperature and pH) was performed to investigate their influence on its properties. Investigation using HRTEM, XPS, Raman spectroscopy, and UV-Vis spectroscopy suggested that hydrothermal conditions affect carbonization reaction. Hydrothermal temperature controls carbonization rate of rice husk ash, while acid addition accelerates polymerization and base addition tends to cut more carbons into small particles. The photoluminescence (PL) analysis showed that the obtained Si-CQD samples have emission in the range of 469–552 nm with various intensities. The application of sole Si-CQDs was evaluated in methylene blue (MB) degradation under visible light irradiation.
关键词： Hydrothermal,Carbon quantum dots,Photocatalyst,Photoluminescence,Rice husk
更新于2025-09-23 15:21:01
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Method for Mapping Rice Fields in Complex Landscape Areas Based on Pre-Trained Convolutional Neural Network from HJ-1 A/B Data
摘要： Accurate and timely information about rice planting areas is essential for crop yield estimation, global climate change and agricultural resource management. In this study, we present a novel pixel-level classi?cation approach that uses convolutional neural network (CNN) model to extract the features of enhanced vegetation index (EVI) time series curve for classi?cation. The goal is to explore the practicability of deep learning techniques for rice recognition in complex landscape regions, where rice is easily confused with the surroundings, by using mid-resolution remote sensing images. A transfer learning strategy is utilized to ?ne tune a pre-trained CNN model and obtain the temporal features of the EVI curve. Support vector machine (SVM), a traditional machine learning approach, is also implemented in the experiment. Finally, we evaluate the accuracy of the two models. Results show that our model performs better than SVM, with the overall accuracies being 93.60% and 91.05%, respectively. Therefore, this technique is appropriate for estimating rice planting areas in southern China on the basis of a pre-trained CNN model by using time series data. And more opportunity and potential can be found for crop classi?cation by remote sensing and deep learning technique in the future study.
关键词： mapping rice ?elds,convolutional neural network,time series of vegetation index,complex landscape,transfer learning
更新于2025-09-23 15:21:01
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Large-scale preparation of rice-husk-derived mesoporous SiO2@TiO2 as efficient and promising photocatalysts for organic contaminants degradation
摘要： Mesoporous SiO2@TiO2 photocatalysts with application prospect for organic contaminants degradation were prepared by utilizing rice husk (RH), an easy-available bioresource, as the biotemplate. Structures and physicochemical properties of RH-derived SiO2@TiO2 photocatalysts were systematically characterized and discussed. Results indicate the RH-derived mesoporous and thermal-stable template, which can postpone the anatase-rutile phase transition of TiO2 at high temperatures, is mainly consisted of tightly compacted amorphous SiO2 nanoparticles. Optimized calcination temperature of 700 °C is positive for preparing the most active RH-derived SiO2@TiO2, which has the anatase phase, mesoporous structure, proper crystalline degree (grain size of 22.75 nm), specific surface area of 41.13 m2/g, and high ability in separating the photogenerated electron-hole pairs, for removal of Rhodamine B (RhB) in aqueous solutions under both the xenon lamp and visible light irradiation. Moreover, large-scale preparation, stable, and recyclable properties of the photocatalysts are also confirmed, which makes them as promising photocatalysts for practical application.
关键词： SiO2@TiO2 mesoporous structure,Biotemplate,Rice husk,Photocatalysis,Practical application
更新于2025-09-23 15:21:01
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Prediction of cadmium concentration in brown rice before harvest by hyperspectral remote sensing
摘要： Cadmium (Cd) contaminated rice has become a global food security issue. Hyperspectral remote sensing can do rapid and nondestructive monitoring of environmental stress in plant. To realize the nondestructive detection of Cd in brown rice before harvest, the leaf spectral reflectance of rice exposed to six different levels of Cd stress was measured during the whole life stages. In addition, the dry weight of rice grain and Cd concentrations in brown rice were measured after harvest. The impact of Cd stress on the quantity and the quality of rice grain and on the leaf reflectance of rice was analyzed, and hyperspectral estimation models for predicting the Cd content in brown rice during three growth stages were established. The results showed that rice plants can impact the quality of the brown rice seriously, even if the impact on the quantity was not significant. All the established models had the capability to estimate Cd concentrations in brown rice (R2 > 0.598), and the best performance model, with the R2 value of 0.873, was use first derivative spectrum of booting stage as variable. It was concluded that the hyperspectral of rice leaves provides a new insight to predict Cd concentration in brown rice before harvest.
关键词： Derivative transformation,Brown rice,Booting stage,Before harvest,Hyperspectral,Cd concentration
更新于2025-09-23 15:21:01
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Green Synthesis of Highly Fluorescent Graphene Oxide/Carbon Quantum Dot Colloid from Rice
摘要： Carbon quantum dot–graphene oxide hybrids have been synthesized from rice precursor using a ball-milling-assisted hydrothermal method. The structure of the quantum dots and graphene oxide was studied using x-ray diffraction analysis, energy-dispersive x-ray spectroscopy, and elemental mapping. The size and morphology of the nanostructures were studied using ?eld-emission scanning electron microscopy and transmission electron microscopy, revealing that the product was composed of spherical nanoparticles and nanosheets. We argue that the presence of some metals in the rice precursor can catalyze the synthesis of graphene oxide. The structure of the product was studied by Fourier-transform infrared spectroscopy. Investigation of the optical properties of the quantum dots and graphene oxide by ultraviolet–visible spectroscopy and photoluminescence (PL) spectroscopy revealed strong PL properties. The PL quantum yield could be improved by surface modi?cation using polyethylene glycol, polyvinylpyrrolidone, ethylenediaminetetraacetic acid, and acetylacetone. The photocatalytic properties of the carbon nanomaterial (CNM) were investigated based on the decomposition of Eriochrome Black-T and Eosin Y dyes, revealing strong photocatalytic activity. The thermal stability of the product was examined by thermogravimetric analysis. Furthermore, atomic absorption spectroscopy showed that CNM could be used to eliminate cations of heavy metals such as lead and cadmium from toxic water.
关键词： Carbon quantum dots,photocatalyst,graphene oxide,photoluminescence,rice,surface adsorption
更新于2025-09-23 15:19:57
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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A Frequency Reconfigurable Slot Antenna Backed by the Substrate Integrated Waveguide Cavity for 5G Applications
摘要： In this paper, a novel near-lossless color ?lter array (CFA) image compression algorithm based on JPEG-LS is proposed for VLSI implementation. It consists of a pixel restoration, a prediction, a run mode, and entropy coding modules. According to the information of the previous research, a context table and row memory consumed more than 81% hardware cost in a JPEG-LS encoder design. Hence, in this paper, a novel context-free and near-lossless image compression algorithm is presented. Since removing the context model causes decreasing of the compression performance, a novel prediction, run mode, and modi?ed Golomb–Rice coding techniques were used to improve the compression ef?ciency. The VLSI architecture of the proposed image compressor consists of a register bank, a pixel restoration module, a predictor, a run mode module, and an entropy encoder. A pipeline technique was used to improve the performance of this. It contains only 10.9k gate count, and the core area is 30 625 μm2, synthesized by using a 90-nm CMOS process. Compared with the previous JPEG-LS designs, this paper reduces the gate counts by 44.1% and 41.7%, respectively, for ?ve standard and eight endoscopy testing images in CFA format. It also improves the average PSNR values by 0.96 and 0.43 dB, respectively, for the same test images.
关键词： JPEG-LS,Color ?lter array,VLSI,context-free,wireless capsule endoscopy,Golomb-Rice coding,near-lossless,run mode
更新于2025-09-23 15:19:57