Hyperspectral seafloor mapping and direct bathymetry calculation using HyMap data from the Ningaloo reef and Rottnest Island areas in Western Australia
Hyperspectral sensing allows us to view the earth not only in a few, but hundreds of different spectral channels over a wide wavelength range and to map the surface composition based on the spectral signatures observed. Applications range from mineral mapping to environmental monitoring, but aquatic spectral mapping has advanced steadily over the last few years as processing time and algorithms become faster and more efficient.
The HyMap airborne spectrometer is an airborne remote sensing instrument collecting data in 126 spectral channels from the visible (VIS) to the shortwave infrared (SWIR) wavelength regions (0.45 to 2.5 um). In the past it has been seen by various scientists as not adequate to provide sufficient spectral information for aquatic applications. With a multitude of applications over the last few years however, it was demonstrated that the high signal to noise ratio allows for good spectral discrimination in the visible wavelength region and the added SWIR spectral modules allow for improved sun-glint removal techniques to be applied. Furthermore any floating substances can be better discriminated from suspended matter by having SWIR channels available.
HyMap data was collected for two aquatic R&D projects in Western Australia: one over the Ningaloo Reef, near Yardie Creek, in N-WA and the other over Rottnest Island near Perth. Bathymetry calculations to 20m and seafloor mapping results are being presented, introducing new processing techniques - developed initially by DLR (Germany) – to Australian waters. These products allow seamless mosaicing of multiple flight lines and demonstrate a high level of accuracy compared to conventional mapping methods. Furthermore they provide 100 % coverage and results on a pixel by pixel base compared to interpolated results derived from line profiling methods
