| Reef scientists continue exploring methods to better characterize the status of coral reefs environments. In that endeavor, an airborne AISA image (1m, 24 bands) was analyzed together with Ikonos (4m, 3 bands), ASTER (15m, 2 bands), and ETM+ (30m, 4 bands) spaceborne data in order to increase the small number of pilot sites (Turk and Caicos, Tahiti) where multi-sensors comparisons are now available. The benefits of atmospheric and water column correction on the accuracy of image classification maps are also assessed. Water-column correction considered both, the empirical Lyzenga's (1978, 1981) approach and the analytical Maritorena's (1994) model. The latter model requires pixel-specific depth measurements and information on the characteristics of the water column. Bathymetry was collected using an airborne lidar sensor. AISA products were consistently more accurate than spaceborne products with a maximum accuracy of 93%. Also, water column correction proved to be beneficial by generally improving classification accuracy for the processed scenes. Other trends were revealed. |
