Spectral data source effect on crop state estimation by vegetation indices

2018 ◽  
Vol 77 (22) ◽  
Author(s):  
Maria Polinova ◽  
Thomas Jarmer ◽  
Anna Brook
2021 ◽  
Author(s):  
Antonello Bonfante ◽  
Arturo Erbaggio ◽  
Eugenia Monaco ◽  
Rossella Albrizio ◽  
Pasquale Giorio ◽  
...  

<p>Currently, the main goal of agriculture is to promote the resilience of agricultural systems in a sustainable way through the improvement of use efficiency of farm resources, increasing crop yield and quality, under climate change conditions. Climate change is one of the major challenges for high incomes crops, as the vineyards for high-quality wines, since it is expected to drastically modify plant growth, with possible negative effects especially in arid and semi-arid regions of Europe. In this context, the reduction of negative environmental impacts of intensive agriculture (e.g. soil degradation), can be realized by means of high spatial and temporal resolution of field crop monitoring, aiming to manage the local spatial variability.</p><p>The monitoring of spatial behaviour of plants during the growing season represents an opportunity to improve the plant management, the farmer incomes and to preserve the environmental health, but it represents an additional cost for the farmer.</p><p>The UAS-based imagery might provide detailed and accurate information across visible and near infrared spectral regions to support monitoring (crucial for precision agriculture) with limitation in bands and then on spectral vegetation indices (Vis) provided. VIs are a well-known and widely used method for crop state estimation. The ability to monitor crop state by such indices is an important tool for agricultural management. While differences in imagery and point-based spectroscopy are obvious, their impact on crop state estimation by VIs is not well-studied. The aim of this study was to assess the performance level of the selected VIs calculated from reconstructed high-resolution satellite (Sentinel-2A) multispectral imagery (13 bands across 400-2500nm with spatial resolution of <2m) through Convolutional Neural Network (CNN) approach (Brook et al., 2020), UAS-based multispectral (5 bands across 450-800nm spectral region with spatial resolution of 5cm) imagery and point-based field spectroscopy (collecting 600 wavelength across  400-1000nm spectral region with a surface footprint of 1-2cm) in application to crop state estimation.</p><p>The test site is a portion of vineyard placed in southern Italy cultivated on Greco cultivar, in which the soil-plant and atmosphere system has been monitored during the 2020 vintage also through ecophysiological analyses. The data analysis will follow the methodology presented in a recently published paper (Polinova et al., 2018).</p><p>The study will connect the method and scale of spectral data collection with in vivo plant monitoring and prove that it has a significant impact on the vegetation state estimation results. It should be noted that each spectral data source has its advantages and drawbacks. The plant parameter of interest should determine not only the VIs type suitable for analysis but also the method of data collection.</p><p>The contribution has been realized within the CNR BIO-ECO project.</p>


2021 ◽  
Author(s):  
Maria Polivova ◽  
Anna Brook

Spectral vegetation indices (VIs) are a well-known and widely used method for crop state estimation. These technologies have great importance for plant state monitoring, especially for agriculture. The main aim is to assess the performance level of the selected VIs calculated from space-borne multispectral imagery and point-based field spectroscopy in application to crop state estimation. The results obtained indicate that space-borne VIs react on phenology. This feature makes it an appropriate data source for monitoring crop development, crop water needs and yield prediction. Field spectrometer VIs were sensitive for estimating pigment concentration and photosynthesis rate. Yet, a hypersensitivity of field spectral measures might lead to a very high variability of the calculated values. The results obtained in the second part of the presented study were reported on crop state estimated by 17 VIs known as sensitive to plant drought. An alternative approach for identification early stress by VIs proposed in this study is Principal Component Analysis (PCA). The results show that PCA has identified the degree of similarity of the different states and together with reference stress states from the control plot clearly estimated stress in the actual irrigated field, which was hard to detect by VIs values only.


2019 ◽  
Vol 11 (17) ◽  
pp. 2066 ◽  
Author(s):  
Nora Tilly ◽  
Georg Bareth

A sufficient nitrogen (N) supply is mandatory for healthy crop growth, but negative consequences of N losses into the environment are known. Hence, deeply understanding and monitoring crop growth for an optimized N management is advisable. In this context, remote sensing facilitates the capturing of crop traits. While several studies on estimating biomass from spectral and structural data can be found, N is so far only estimated from spectral features. It is well known that N is negatively related to dry biomass, which, in turn, can be estimated from crop height. Based on this indirect link, the present study aims at estimating N concentration at field scale in a two-step model: first, using crop height to estimate biomass, and second, using the modeled biomass to estimate N concentration. For comparison, N concentration was estimated from spectral data. The data was captured on a spring barley field experiment in two growing seasons. Crop surface height was measured with a terrestrial laser scanner, seven vegetation indices were calculated from field spectrometer measurements, and dry biomass and N concentration were destructively sampled. In the validation, better results were obtained with the models based on structural data (R2 < 0.85) than on spectral data (R2 < 0.70). A brief look at the N concentration of different plant organs showed stronger dependencies on structural data (R2: 0.40–0.81) than on spectral data (R2: 0.18–0.68). Overall, this first study shows the potential of crop-specific across‑season two-step models based on structural data for estimating crop N concentration at field scale. The validity of the models for in-season estimations requires further research.


2017 ◽  
Vol 9 (2) ◽  
pp. 39
Author(s):  
Susilawati S. ◽  
Enjang Jaenal Mustopa

<p class="abstrak">CSAMT or Controlled Source Audio-Magnetotelluric is one of the Geophysics methods to determine the resistivity of rock under earth surface. CSAMT method utilizes artificial stream and injected into the ground, the frequency of artificial sources ranging from 0.1 Hz to 10 kHz, CSAMT data source effect correction is inverted. From the inversion results showed that there is a layer having resistivity values ranged between 2.5 Ω.m – 15 Ω.m, which is interpreted that the layer is clay.</p><p class="abstrak"><span lang="EN-US"><br /></span></p>


2013 ◽  
Vol 732-733 ◽  
pp. 1283-1287
Author(s):  
Jun Liu ◽  
Da Wei Su ◽  
Ke Jun Qian ◽  
Fei Shi ◽  
Li Wen Wang

In this paper, a method of distributed state estimation in dispatch center based on ripe data and bus topology information of substation is proposed. Substation state estimation solves the reliability issues of basic data by means of processing the redundant information in substation side. By using a large amount of data source information of substation, state estimation can be performed efficiently in substation. On the basis of the unified data standard between master center and substation, uploading ripe data and calculation nodes topology structure are acquired in dispatch center level. Data rationality and consistency check of substation improve the state estimation accuracy of topology identification in dispatch master system. And also it provides reliable data for the online analysis software.


2017 ◽  
Vol 4 (3) ◽  
pp. 265-268
Author(s):  
D. Simek ◽  
D. Pecek

Low voltage switching apparatuses efficiency depends on the speed of movement of the switching arc from the contacts to the quenching chamber. The paper is focused on investigation of this movement of an arc. Measurement of radiation spectra of the electric arc burning inside miniature circuit breaker and moving to quenching chamber are presented. Measured radiation spectra contain suitable atomic spectra lines for calculation purposes. The problems connected with the measurements are discussed. The main part of the paper deals with a calculation of temperature of the investigated plasma of the arc. Atomic lines database of National Institute of Standards and Technology was used as a spectral data source for the calculations.


2013 ◽  
Vol 34 (8) ◽  
pp. 2888-2904 ◽  
Author(s):  
Eugenia Roumenina ◽  
Valentin Kazandjiev ◽  
Petar Dimitrov ◽  
Lachezar Filchev ◽  
Vassil Vassilev ◽  
...  

2017 ◽  
Vol 31 (3) ◽  
pp. 419-432 ◽  
Author(s):  
Bogna Uździcka ◽  
Marcin Stróżecki ◽  
Marek Urbaniak ◽  
Radosław Juszczak

AbstractThe aim of this paper is to demonstrate that spectral vegetation indices are good indicators of parameters describing the intensity of CO2exchange between crops and the atmosphere. Measurements were conducted over 2011-2013 on plots of an experimental arable station on winter wheat, winter rye, spring barley, and potatoes. CO2fluxes were measured using the dynamic closed chamber system, while spectral vegetation indices were determined using SKYE multispectral sensors. Based on spectral data collected in 2011 and 2013, various models to estimate net ecosystem productivity and gross ecosystem productivity were developed. These models were then verified based on data collected in 2012. The R2for the best model based on spectral data ranged from 0.71 to 0.83 and from 0.78 to 0.92, for net ecosystem productivity and gross ecosystem productivity, respectively. Such high R2values indicate the utility of spectral vegetation indices in estimating CO2fluxes of crops. The effects of the soil background turned out to be an important factor decreasing the accuracy of the tested models.


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