scholarly journals Identification of Rice Sheath Blight through Spectral Responses Using Hyperspectral Images

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6243 ◽  
Author(s):  
Fenfang Lin ◽  
Sen Guo ◽  
Changwei Tan ◽  
Xingen Zhou ◽  
Dongyan Zhang
Keyword(s):  
Leaf Blade ◽  
Near Infrared ◽  
Spectral Feature ◽  
Sheath Blight ◽  
Peak Amplitude ◽  
Blue Edge ◽  
Red Edge ◽  
Tree Classifier ◽  
Significant Difference ◽  
Spectral Responses

Sheath blight (ShB), caused by Rhizoctonia solani AG1-I, is one of the most important diseases in rice worldwide. The symptoms of ShB primarily develop on leaf sheaths and leaf blades. Hyperspectral remote sensing technology has the potential of rapid, efficient and accurate detection and monitoring of the occurrence and development of rice ShB and other crop diseases. This study evaluated the spectral responses of leaf blade fractions with different development stages of ShB symptoms to construct the spectral feature library of rice ShB based on “three-edge” parameters and narrow-band vegetation indices to identify the disease on the leaves. The spectral curves of leaf blade lesions have significant changes in the blue edge, green peak, yellow edge, red valley, red edge and near-infrared regions. The variables of the normalized index between green peak amplitude and red valley amplitude (Rg − Ro)/(Rg + Ro), the normalized index between the yellow edge area and blue edge area (SDy − SDb)/(SDy + SDb), the ratio index of green peak amplitude and red valley amplitude (Rg/Ro) and the nitrogen reflectance index (NRI) had high relevance to the disease. At the leaf scale, the importance weights of all attributes decreased with the effect of non-infected areas in a leaf by the ReliefF algorithm, with Rg/Ro being the indicator having the highest importance weight. Estimation rate of 95.5% was achieved in the decision tree classifier with the parameter of Rg/Ro. In addition, it was found that the variety degree of absorptive valley, reflection peak and reflecting steep slope was different in the blue edge, green and red edge regions, although there were similar spectral curve shapes between leaf sheath lesions and leaf blade lesions. The significant difference characteristic was the ratio index of the red edge area and green peak area (SDr/SDg) between them. These results can provide the basis for the development of a specific sensor or sensors system for detecting the ShB disease in rice.

scholarly journals Characterization and mapping of hematite ore mineral classes using hyperspectral remote sensing technique: a case study from Bailadila iron ore mining region

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Ibrahim Shaik ◽  
S. K. Begum ◽  
P. V. Nagamani ◽  
Narayan Kayet
Keyword(s):  
Infrared Absorption ◽  
Near Infrared ◽  
Spectral Feature ◽  
Absorption Feature ◽  
X Ray ◽  
Remote Sensing Technique ◽  
Ore Minerals ◽  
Feature Fitting ◽  
Hematite Ore

AbstractThe study demonstrates a methodology for mapping various hematite ore classes based on their reflectance and absorption spectra, using Hyperion satellite imagery. Substantial validation is carried out, using the spectral feature fitting technique, with the field spectra measured over the Bailadila hill range in Chhattisgarh State in India. The results of the study showed a good correlation between the concentration of iron oxide with the depth of the near-infrared absorption feature (R2 = 0.843) and the width of the near-infrared absorption feature (R2 = 0.812) through different empirical models, with a root-mean-square error (RMSE) between < 0.317 and < 0.409. The overall accuracy of the study is 88.2% with a Kappa coefficient value of 0.81. Geochemical analysis and X-ray fluorescence (XRF) of field ore samples are performed to ensure different classes of hematite ore minerals. Results showed a high content of Fe > 60 wt% in most of the hematite ore samples, except banded hematite quartzite (BHQ) (< 47 wt%).

Selective Determination of Entecavir in the Presence of Its Oxidative Degradate by Spectrophotometric and Chromatographic Methods

2021 ◽  
Author(s):  
Heba M El-Sayed ◽  
Laila E Abdel Fattah ◽  
Hisham E Abdellatef ◽  
Maha A Hegazy ◽  
Mai M Abd El-Aziz
Keyword(s):  
High Selectivity ◽  
Oxidative Degradation ◽  
Hplc Method ◽  
Peak Amplitude ◽  
Quality Analysis ◽  
Official Method ◽  
Selective Determination ◽  
Significant Difference ◽  
Development And Validation

Abstract Background Entecavir (ENT) is an antiretroviral agent prescribed for treatment of HBV and HIV. Objective Development and validation of three simple, sensitive, selective, and precise methods for determination of ENT in presence of its oxidative degradation product (ENT deg.). Methods The first method was based on second derivative (D2) spectrophotometry through measuring the peak amplitude of D2 spectra at 293.6 nm. The second one is mean centering of the ratio spectra (MCR), which allowed measuring the peak amplitude at 280.0 nm. While the third method was HPLC; where ENT was separated from ENT deg. using Zobrax C18column and methanol: water (30:70, v/v), pH 3 as a mobile phase. The three developed methods were validated according to ICH guidelines. Results Linearity range of ENT was 5.00–50.00 μg/mL for both D2and MCR. However, higher sensitivity was achieved using HPLC (1.00–50.00 μg/mL). Accuracy of ENT were 100.60%±0.547, 101.55%±1.2071 and 100.61%±1.207 for D2, MCR and HPLC methods, respectively, and precision was within 1.280. Conclusions The developed methods were successfully applied for the determination of ENT in Tecavir® tablets without interference from ENT deg. They showed no significant difference compared with the official method as well as they could be applied in the quality analysis of ENT with high selectivity, accuracy, and precision. Highlights ENT was quantified using two spectrophotometric (D2 and MCR) methods and an HPLC method in presence of ENT deg. The proposed methods were applied to analysis of ENT tablets with high selectivity, sensitivity, and accuracy.

scholarly journals Assessing Leaf Biomass of Agave sisalana Using Sentinel-2 Vegetation Indices

2021 ◽  
Vol 13 (2) ◽  
pp. 233
Author(s):  
Ilja Vuorinne ◽  
Janne Heiskanen ◽  
Petri K. E. Pellikka
Keyword(s):  
Near Infrared ◽  
Vegetation Indices ◽  
Fibre Production ◽  
Additive Models ◽  
Leaf Biomass ◽  
Ground Vegetation ◽  
Perennial Crop ◽  
Red Edge ◽  
Agave Sisalana ◽  
Sentinel 2

Biomass is a principal variable in crop monitoring and management and in assessing carbon cycling. Remote sensing combined with field measurements can be used to estimate biomass over large areas. This study assessed leaf biomass of Agave sisalana (sisal), a perennial crop whose leaves are grown for fibre production in tropical and subtropical regions. Furthermore, the residue from fibre production can be used to produce bioenergy through anaerobic digestion. First, biomass was estimated for 58 field plots using an allometric approach. Then, Sentinel-2 multispectral satellite imagery was used to model biomass in an 8851-ha plantation in semi-arid south-eastern Kenya. Generalised Additive Models were employed to explore how well biomass was explained by various spectral vegetation indices (VIs). The highest performance (explained deviance = 76%, RMSE = 5.15 Mg ha−1) was achieved with ratio and normalised difference VIs based on the green (R560), red-edge (R740 and R783), and near-infrared (R865) spectral bands. Heterogeneity of ground vegetation and resulting background effects seemed to limit model performance. The best performing VI (R740/R783) was used to predict plantation biomass that ranged from 0 to 46.7 Mg ha−1 (mean biomass 10.6 Mg ha−1). The modelling showed that multispectral data are suitable for assessing sisal leaf biomass at the plantation level and in individual blocks. Although these results demonstrate the value of Sentinel-2 red-edge bands at 20-m resolution, the difference from the best model based on green and near-infrared bands at 10-m resolution was rather small.

scholarly journals Assessment of cervical and ocular vestibular evoked myogenic potentials in migraine patients

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Doaa Elmoazen ◽  
Hesham Kozou ◽  
Jaidaa Mekky ◽  
Dalia Ghanem
Keyword(s):  
Vestibular Function ◽  
Vestibular Dysfunction ◽  
Peak Amplitude ◽  
Vestibular Evoked Myogenic Potentials ◽  
Healthy Controls ◽  
Latency Difference ◽  
Significant Difference ◽  
Cervical Vemp ◽  
Vestibular Symptoms ◽  
Function Assessment

Abstract Background Patients suffering from vestibular migraine (VM) are known to have various vestibular test abnormalities interictally and ictally. Recently, vestibular evoked myogenic potentials (VEMPs) have become accepted as a valid method for otolith function assessment. Many studies have identified various vestibular symptoms and laboratory abnormalities in migraineurs. Since migraineurs with no accompanying vestibular symptoms might exhibit subclinical vestibular dysfunction, we investigated vestibular function using ocular and cervical VEMPs in migraine patients. The aim was to study cervical VEMP and occular VEMP in migraineurs with and without vestibular symptoms interictally. Results Migraine and VM patients showed significantly longer P13 latency of cVEMP compared to controls. A statistically significant cVEMP interaural P13 latency difference was found in VM compared to healthy controls. Cervical VEMP N23 latency, peak-to-peak amplitude, interaural N23 latency, and amplitude asymmetric ratio did not show any significant difference in migraine and VM patients compared to healthy controls as well as no significant difference across the three groups regarding oVEMP parameters. Conclusions Abnormal interictal cVEMP results in migraineurs might indicate subclinical vestibulo-collic pathway dysfunction.

scholarly journals Spaceborne Estimation of Leaf Area Index in Cotton, Tomato, and Wheat Using Sentinel-2

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 505
Author(s):  
Gregoriy Kaplan ◽  
Offer Rozenstein
Keyword(s):  
Water Vapor ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Vegetation Index ◽  
Near Infrared ◽  
Linear Regression Models ◽  
Area Index ◽  
Estimation Performance ◽  
Red Edge ◽  
Sentinel 2

Satellite remote sensing is a useful tool for estimating crop variables, particularly Leaf Area Index (LAI), which plays a pivotal role in monitoring crop development. The goal of this study was to identify the optimal Sentinel-2 bands for LAI estimation and to derive Vegetation Indices (VI) that are well correlated with LAI. Linear regression models between time series of Sentinel-2 imagery and field-measured LAI showed that Sentinel-2 Band-8A—Narrow Near InfraRed (NIR) is more accurate for LAI estimation than the traditionally used Band-8 (NIR). Band-5 (Red edge-1) showed the lowest performance out of all red edge bands in tomato and cotton. A novel finding was that Band 9 (Water vapor) showed a very high correlation with LAI. Bands 1, 2, 3, 4, 5, 11, and 12 were saturated at LAI ≈ 3 in cotton and tomato. Bands 6, 7, 8, 8A, and 9 were not saturated at high LAI values in cotton and tomato. The tomato, cotton, and wheat LAI estimation performance of ReNDVI (R2 = 0.79, 0.98, 0.83, respectively) and two new VIs (WEVI (Water vapor red Edge Vegetation Index) (R2 = 0.81, 0.96, 0.71, respectively) and WNEVI (Water vapor narrow NIR red Edge Vegetation index) (R2 = 0.79, 0.98, 0.79, respectively)) were higher than the LAI estimation performance of the commonly used NDVI (R2 = 0.66, 0.83, 0.05, respectively) and other common VIs tested in this study. Consequently, reNDVI, WEVI, and WNEVI can facilitate more accurate agricultural monitoring than traditional VIs.

scholarly journals Evaluation of Different Near-Infrared Spectroscopy Devices for Assessing Tissue Oxygenation with a Vascular Occlusion Test in Healthy Volunteers

2020 ◽  
Vol 57 (6) ◽  
pp. 341-347
Author(s):  
Jaeyeon Chung ◽  
Sang-Hwan Ji ◽  
Young-Eun Jang ◽  
Eun-Hee Kim ◽  
Ji-Hyun Lee ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Pairwise Comparison ◽  
Vascular Occlusion ◽  
Tissue Oxygen Saturation ◽  
Vascular Occlusion Test ◽  
Occlusion Test ◽  
Significant Difference ◽  
Post Hoc

Near-infrared spectroscopy devices can measure peripheral tissue oxygen saturation (StO<sub>2</sub>). This study aims to compare StO<sub>2</sub> using INVOS® and different O3™ settings (O3<sup>25:75</sup> and O3<sup>30:70</sup>). Twenty adults were recruited. INVOS® and O3™ probes were placed simultaneously on 1 side of forearm. After baseline measurement, the vascular occlusion test was initiated. The baseline value, rate of deoxygenation and reoxygenation, minimum and peak StO<sub>2</sub>, and time from cuff release to peak value were measured. The parameters were compared using ANOVA and Kruskal-Wallis tests. Bonferroni’s correction and Mann-Whitney pairwise comparison were used for post hoc analysis. The agreement between StO<sub>2</sub> of devices was evaluated using Bland-Altman plots. INVOS® baseline value was higher (79.7 ± 6.4%) than that of O3<sup>25:75</sup> and O3<sup>30:70</sup> (62.4 ± 6.0% and 63.7 ± 5.5%, respectively, <i>p</i> &#x3c; 0.001). The deoxygenation rate was higher with INVOS® (10.6 ± 2.1%/min) than with O3<sup>25:75</sup> and O3<sup>30:70</sup> (8.4 ± 2.2%/min, <i>p</i> = 0.006 and 7.5 ± 2.1%/min, <i>p</i> &#x3c; 0.001). The minimum and peak StO<sub>2</sub> were higher with INVOS®. No significant difference in the reoxygenation rate was found between the devices and settings. The time to reach peak after cuff deflation was faster with INVOS® (both <i>p</i> &#x3c; 0.001). Other parameters were similar. There were no differences between the different O3™ settings. There were differences in StO<sub>2</sub> measurements between the devices, and these devices should not be interchanged. Differences were not observed between O3™ device settings.

Fast Non-Destructive Detection of Wool Content in Blended Fabrics Based on Near-Infrared Spectroscopy Technology

2015 ◽  
Vol 671 ◽  
pp. 356-362 ◽  
Author(s):  
Zhi Feng Chen ◽  
Yuan Quan Hong ◽  
Chang Jiang Wan ◽  
Lian Ying Zhao
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Detection Method ◽  
Quantitative Model ◽  
National Standard ◽  
Fast Detection ◽  
Significant Difference ◽  
Validation Set ◽  
Non Destructive

A fast non-destructive method of detection of wool content in blended fabrics was studied based on Near Infrared spectroscopy technology in order to avoid the time-consuming, tedious work and the destruction of samples in the traditional inspection. 621 wool/nylon, wool/polyester and wool/nylon/polyester blended fabrics were taken as research objects. To get the wool content, we established the wool near-infrared quantitative model by partial least squares (PLS) method after analyzing the color and composition of the samples. For verifying the validity and practicability of the model, 100 samples were chosen as an independent validation set. The variance analysis shows that there is no significant difference between Near Infrared fast detection method and national standard method (GB/T2910-2009),which indicates that this method is expected to be a means of fast non-destructive detection and will have extensive application future in the field of wool content detection.

Calibration Transfer between Miniature Photodiode Array-Based Spectrometers in the near Infrared Assessment of Mandarin Soluble Solids Content

2002 ◽  
Vol 10 (1) ◽  
pp. 27-35 ◽  
Author(s):  
C.V. Greensill ◽  
K.B. Walsh
Keyword(s):  
Near Infrared ◽  
Model Updating ◽  
Soluble Solids ◽  
Soluble Solid Content ◽  
Calibration Model ◽  
Calibration Transfer ◽  
Orthogonal Signal Correction ◽  
Significant Difference ◽  
Photodiode Array ◽  
Direct Standardisation

The transfer of predictive models among photodiode array based, short wave near infrared spectrometers using the same illumination/detection optical geometry has been attempted using various chemometric techniques, including slope and bias correction (SBC), direct standardisation (DS), piecewise direct standardisation (PDS), double window PDS (DWPDS), orthogonal signal correction (OSC), finite impulse transform (FIR) and wavelet transform (WT). Additionally, an interpolation and photometric response correction method, a wavelength selection method and a model updating method were assessed. Calibration transfer was attempted across two populations of mandarin fruit. Model performance was compared in terms of root mean squared error of prediction ( RMSEP), using Fearn's significance testing, for calibration transfer (standardisation) between pairs of spectrometers from a group of four spectrometers. For example, when a calibration model (Root Mean Square Error of Cross-Validation [ RMSECV = 0.26% soluble solid content (SSC)], developed on one spectrometer, was used with spectral data collected on another spectrometer, a poor prediction resulted ( RMSEP = 2.5% SSC). A modified WT method performed significantly better (e.g. RMSEP = 0.25% SSC) than all other standardisation methods (10 of 12 cases), and almost on a par with model updating (MU) (nine cases with no significant difference, one case and two cases significantly better for WT and MU, respectively).

Near-infrared fluorescence imaging with indocyanine green for quantification of changes in tissue perfusion following revascularization

Vascular ◽  
2021 ◽  
pp. 170853812110328
Author(s):  
Pim Van den Hoven ◽  
Floris S Weller ◽  
Merel Van De Bent ◽  
Lauren N Goncalves ◽  
Melissa Ruig ◽  
...  
Keyword(s):  
Indocyanine Green ◽  
Fluorescence Imaging ◽  
Fluorescence Intensity ◽  
Near Infrared ◽  
Tissue Perfusion ◽  
Control Group ◽  
Maximum Slope ◽  
Nir Fluorescence ◽  
Significant Difference ◽  
Revascularization Procedures

Objectives Current diagnostic modalities for patients with peripheral artery disease (PAD) mainly focus on the macrovascular level. For assessment of tissue perfusion, near-infrared (NIR) fluorescence imaging using indocyanine green (ICG) seems promising. In this prospective cohort study, ICG NIR fluorescence imaging was performed pre- and post-revascularization to assess changes in foot perfusion. Methods ICG NIR fluorescence imaging was performed in 36 patients with PAD pre- and post-intervention. After intravenous bolus injection of 0.1 mg/kg ICG, the camera registered the NIR fluorescence intensity over time on the dorsum of the feet for 15 min using the Quest Spectrum Platform®. Time-intensity curves were plotted for three regions of interest (ROI): (1) the dorsum of the foot, (2) the forefoot, and (3) the hallux. Time-intensity curves were normalized for maximum fluorescence intensity. Extracted parameters were the maximum slope, area under the curve (AUC) for the ingress, and the AUC for the egress. The non-treated contralateral leg was used as a control group. Results Successful revascularization was performed in 32 patients. There was a significant increase for the maximum slope and AUC egress in all three ROIs. The most significant difference was seen for the maximum slope in ROI 3 (3.7%/s to 6.6%/s, p < 0.001). In the control group, no significant differences were seen for the maximum slope and AUC egress in all ROIs. Conclusions This study shows the potential of ICG NIR fluorescence imaging in assessing the effect of revascularization procedures on foot perfusion. Future studies should focus on the use of this technique in predicting favorable outcome of revascularization procedures.

scholarly journals Spectral responses in near-infrared of the mixed compounds III-V, ternary and quaternary, based on GaSb

1993 ◽  
Vol 3 (9) ◽  
pp. 1777-1782
Author(s):  
B. Mbow ◽  
N. Rezzoug ◽  
C. Peremarti ◽  
A. Mezerreg ◽  
C. Llinares
Keyword(s):  
Near Infrared ◽  
Spectral Responses
Sign in / Sign up

Export Citation Format

Share Document