Bathymetric map of Heron Reef, Australia, derived from airborne hyperspectral data at 1 m resolution

A simple method for efficient inversion of arbitrary radiative transfer models for image analysis is presented. The method operates by representing the shape of the function that maps model parameters to spectral reflectance by an adaptive look-up tree (ALUT) that evenly distributes the discretization error of tabulated reflectances in spectral space. A post-processing step organizes the data into a binary space partitioning tree that facilitates an efficient inversion search algorithm. In an example shallow water remote sensing application, the method performs faster than an implementation of previously published methodology and has the same accuracy in bathymetric retrievals. The method has no user configuration parameters requiring expert knowledge and minimizes the number of forward model runs required, making it highly suitable for routine operational implementation of image analysis methods. For the research community, straightforward and robust inversion allows research to focus on improving the radiative transfer models themselves without the added complication of devising an inversion strategy. A bathymetric map of Heron Reef, Great Barrier Reef, Australia at 1 m resolution. The map is derived from Compact Airborne Spectrographic Imager (CASI) data acquired on 1st and 3rd of July 2002, latitude -23.45, longitude 151.92. The data was processed using a radiative transfer model inversion technique, fully described in the related article, Hedley et al. 2009. This dataset corresponds to the treatment described as "Detailed Depth ALUT" in that paper and shown in Figure 5c. The data is not tide corrected and consists of stitched flight lines taken at slightly different times, the linear discontinuity seen across the right of the image is probably due to small tidal variation between flight line times. Small gaps in the image are due to gaps in coverage between the flight lines.