@InProceedings{SanchesSouz:2014:CoReAn,
               author = "Sanches, Ieda Del'Arco and Souza Filho, Carlos Roberto de",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and Institute 
                         of Geosciences, University of Campinas (UNICAMP), Brazil",
                title = "Continuum Removal Analysis of the chlorophyll absorption feature 
                         to detect plant stress induced by liquid hydrocarbon 
                         contamination",
            booktitle = "Proceedings...",
                 year = "2014",
         organization = "International Geoscience and Remote Sensing Symposium, (IGARSS).",
            publisher = "IEEE",
             abstract = "This work explores the continuum removal (CR) technique to detect 
                         plant stress in visible/near infrared wavelengths. The red edge of 
                         the 680 nm chlorophyll absorption is a key feature in plant stress 
                         studies (e.g., [1], [8], [7]). The CR transformation consists of 
                         estimating the absorptions not due to the band of interest and 
                         removing their effects [2]. The CR technique normalises the 
                         reflectance spectrum and isolates absorption features to allow 
                         comparison between absorption bands on a common basis [4]. The CR 
                         method was initially used in geological remote sensing and was 
                         first applied to studies of leaf biochemistry by [5]. [6] 
                         demonstrated that the distinction between healthy and contaminated 
                         plant samples was improved when analysing the continuum-removed 
                         reflectance compared to reflectance and first derivative of 
                         reflectance data. In that study, they applied the CR using fixed 
                         continuum channels (e.g. 550-570 nm). Pre-stipulated wavelengths 
                         (i.e. left and right channels) used to determine the continuum 
                         line for the CR of a specific absorption feature can be adjusted 
                         for each sample to better represent the feature (PRISM software, 
                         [3]). In the present study, a time series of close range canopy 
                         reflectance data of a grass plant species (Brachiaria brizantha) 
                         grown in liquid hydrocarboncontaminated (diesel DSL; gasoline-GSL) 
                         soil was acquired with a portable spectrometer (ASD FieldSpec® 3 
                         Hi-Res). The parameters describing the chlorophyll 680 nm 
                         absorption feature (continuum channels, depth, width, and area) 
                         were derived using the CR applied to the spectra using fixed (FIX) 
                         and adjusted (ADJ) continuum channels. Differences between CR-FIX 
                         and CR-ADJ results are observed in Figure 1 for all parameters but 
                         the feature centre (Table 1). Left and right channels of the 
                         continuum line differs some 16 nm and 8 nm on average, 
                         respectively, for the FIX and ADJ methods. In addition, the mean 
                         depth, width (FWHM full width at half maximum) and area of the 680 
                         nm feature yielded with the ADJ technique showed higher values. 
                         The analysis of the parameters estimated for the 680 nm absorption 
                         feature (CR-ADJ) for each of the contamination treatments, 
                         indicates that plants stressed by DSL and GSL display mean values 
                         of depth, width and area substantially lower than healthy plants 
                         (CTR) (Table 2). The results imply that to better characterize an 
                         absorption feature, the application of the CR technique using 
                         adjusted channels is superior and should be favoured in the 
                         analysis. Plant stress in brachiaria grass induced by the 
                         contamination of soil with DSL and GSL can be detected with 
                         spectral feature analysis focusing on the depth, width or area of 
                         the 680 nm chlorophyll absorption feature.",
  conference-location = "Quebec",
      conference-year = "2014",
                 isbn = "9781479957750",
                label = "lattes: 2456184661855977 1 SanchesSouz:2014:CoReAn",
             language = "en",
           targetfile = "1407sanches.pdf",
        urlaccessdate = "25 abr. 2024"
}