Hyperspectral imaging for benthic species recognition in shallow coastal waters

Airborne hyperspectral data was collected in April 1999 over 16 square kilometres of coastal waters adjacent to the South Australian Bolivar Wastewater Treatment Plant (near Adelaide). Concurrent in situ measurements of benthic reflectances were collected. A subsequent field-work mission to validate the 1999 image analysis was completed in February 2000. The aim was to map substrate type accurately, differentiating species and canopy density, if possible. The analysis approach was based on the coupling of radiative transfer models using in situ atmospheric measurements and inwater measurements to remove atmospheric and water column effects from the image data. After removal of atmospheric effects, the spectral variation is a function of the water columns constituents and spatial related effects along the image. Water samples were collected at the time of the flights and analysed for the retrieval of inherent optical properties (IOPs). The SpecTool software was used to derive benthic reflectance models based on the IOPs. The atmospheric and in-water radiative transfer corrections applied to the imagery enabled delivery of environmental baseline data of the substrate and a basis for accurate multitemporal data analysis.