Derivative analysis of absorption features in hyperspectral remote sensing data of carbonate sediments

Abstract

This study uses derivative spectroscopy to assess qualitative and quantitative information regarding seafloor types that can be extracted from hyperspectral remote sensing reflectance signals. Carbonate sediments with variable concentrations of microbial pigments were used as a model system. Reflectance signals measured directly over sediment bottoms were compared with remotely sensed data from the same sites collected using an airborne sensor. Absorption features associated with accessory pigments in the sediments were lost to the water column. However major sediment pigments, chlorophyll a and fucoxanthin, were identified in the remote sensing spectra and showed quantitative correlation with sediment pigment concentrations. Derivative spectra were also used to create a simple bathymetric algorithm. Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 2002 Optical Society of America

Vertical cell movement is a primary response of intertidal benthic biofilms to increasing light dose

“…The derivative spectra (δ) were calculated using a finite approximation method (Louchard et al 2002), after smoothing the reflectance spectra with a natural cubic spline function (60 nodes). The second derivative (δδ) was chosen because in theory it eliminates the background effects and strongly enhances minute changes in the reflectance spectra.…”

Interpretation of hyperspectral remote-sensing imagery by spectrum matching and look-up tables

“…Hochberg and Atkinson 2 used Advanced Airborne Hyperspectral Imaging System imagery, and Andréfouët et al 3 used the Compact Airborne Spectrometer Imager for mapping and classification of benthic types into corals, algae, and sediments by fourth-derivative analysis of remotely sensed reflectance spectra. Louchard et al 4 used derivative analysis to classify carbonate sediments. Dierssen et al 5 used spectral ratios derived from Ocean PHILLS imagery of shallow Bahamian waters to extract bathymetry and bottom type; Louchard et al 6 used spectrum matching for the same purpose on the same imagery.…”

“…Kohler 18 compared PHILLS spectra from the 1999 version of this instrument with Hyper-TSRB data and found that both an offset and a gain were necessary to bring the PHILLS spectra into agreement with the Hyper-TSRB spectra. Louchard et al 4,6 also adjusted spectra from the 1999 version of the PHILLS instrument by subtracting the difference of a deep-water PHILLS spectrum and a HydroLight-computed spectrum for infinitely deep water from each shallow-water spectrum. We thus hypothesize that our PHILLS spectra are systematically too large, which is consistent with an undercorrection of atmospheric effects caused by using a 2 m s Ϫ1 wind speed in TAFKAA.…”

Sensor Capability and Atmospheric Correction in Ocean Colour Remote Sensing

“…Derivative spectroscopy has been used in a range of hyperspectral ocean studies to discriminate between healthy and unhealthy corals [255], to identify bottom types in shallow waters [256] and to classify different groups of phytoplankton [252,257,258]. A number of recent works have demonstrated the potential for this technique to analyse complex coastal waters [259,260] and atmospheric effects such as thin cirrus clouds and aerosols [253].…”