The costs and benefits of image acquisition and pre-processing for coral reef remote sensing

[Extract] With the large variety of image data products currently available, users have a big task in determining which image will best suit their needs, budget and staff expertise for processing and analysing the data. It is important to realise that while there are many new and exciting data types available, purchasing a product does not necessarily mean that upon delivery it will be immediately useable for high-level analysis. Uncorrected, raw image data with all its inherent distortions may be not more useful than a wall hanging. The most commonly cited pre-processing operations reduce atmospheric attenuation and assign coordinates to your image so that you can locate yourself and your field sites. Other tasks may be to remove variable brightening effects (eg. hotspots) or sun glitter from the surface of water bodies. Here we outline some of these pre-processing requirements in marine environments for different image data types, both multispectral and hyperspectral, from airborne and satellite platforms.