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oe1(光电查) - 科学论文

3 条数据
?? 中文(中国)
  • Prediction of Sugarcane Yield Based on NDVI and Concentration of Leaf-Tissue Nutrients in Fields Managed with Straw Removal

    摘要: The total or partial removal of sugarcane (Saccharum spp. L.) straw for bioenergy production may deplete soil quality and consequently affect negatively crop yield. Plants with lower yield potential may present lower concentration of leaf-tissue nutrients, which in turn changes light reflectance of canopy in different wavelengths. Therefore, vegetation indexes, such as the normalized difference vegetation index (NDVI) associated with concentration of leaf-tissue nutrients could be a useful tool for monitoring potential sugarcane yield changes under straw management. Two sites in S?o Paulo state, Brazil were utilized to evaluate the potential of NDVI for monitoring sugarcane yield changes imposed by different straw removal rates. The treatments were established with 0%, 25%, 50%, and 100% straw removal. The data used for the NDVI calculation was obtained using satellite images (CBERS-4) and hyperspectral sensor (FieldSpec Spectroradiometer, Malvern Panalytical, Almelo, Netherlands). Besides sugarcane yield, the concentration of the leaf-tissue nutrients (N, P, K, Ca, and S) were also determined. The NDVI efficiently predicted sugarcane yield under different rates of straw removal, with the highest performance achieved with NDVI derived from satellite images than hyperspectral sensor. In addition, leaf-tissue N and P concentrations were also important parameters to compose the prediction models of sugarcane yield. A prediction model approach based on data of NDVI and leaf-tissue nutrient concentrations may help the Brazilian sugarcane sector to monitor crop yield changes in areas intensively managed for bioenergy production.

    关键词: vegetation index,satellite images,yield monitoring,hyperspectral sensor,crop residue management,remote sensing

    更新于2025-09-19 17:15:36

  • [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 - Modtran <sup>?</sup> 6 Multiple Line-Of-Sight (MLOS) Option

    摘要: The MODTRAN6 radiative transfer model enjoys widespread use throughout the remote sensing community. A multiple line-of-sight option is now available that dramatically increases processing time when spectral transmittances and radiances are required for multiple paths within a scene. The option is demonstrated for three applications: (1) modeling residuals between plane-parallel and spherical earth atmosphere hemispherical fluxes; (2) computing wave boundary layer weighting functions; and (3) generating look-up tables for simulating an airborne visible through shortwave infrared hyperspectral sensor.

    关键词: weighting functions,MODTRAN radiative transfer,wave boundary layer,DISORT scatter,hyperspectral sensor look-up table,hemispherical flux

    更新于2025-09-10 09:29:36

  • Assessment of Component Selection Strategies in Hyperspectral Imagery

    摘要: Hyperspectral imagery (HSI) integrates many continuous and narrow bands that cover different regions of the electromagnetic spectrum. However, the main challenge is the high dimensionality of HSI data due to the 'Hughes' phenomenon. Thus, dimensionality reduction is necessary before applying classification algorithms to obtain accurate thematic maps. We focus the study on the following feature-extraction algorithms: Principal Component Analysis (PCA), Minimum Noise Fraction (MNF), and Independent Component Analysis (ICA). After a literature survey, we have observed a lack of a comparative study on these techniques as well as accurate strategies to determine the number of components. Hence, the first objective was to compare traditional dimensionality reduction techniques (PCA, MNF, and ICA) in HSI of the Compact Airborne Spectrographic Imager (CASI) sensor and to evaluate different strategies for selecting the most suitable number of components in the transformed space. The second objective was to determine a new dimensionality reduction approach by dividing the CASI HSI regarding the spectral regions covering the electromagnetic spectrum. The components selected from the transformed space of the different spectral regions were stacked. This stacked transformed space was evaluated to see if the proposed approach improves the final classification.

    关键词: hyperspectral sensor,remote sensing,texture measurement,classification,feature-extraction,ecosystem management

    更新于2025-09-09 09:28:46