These are the figures from the manuscript. Click on the figures to view full resolution images.
Figure 1. Mean (-) and ± 95% confidence intervals (--) for Kaneohe Bay coral reflectance (A) and fourth-derivative (B) spectra (n = 135). Numbers in (B) indicate wavelengths of major peaks; the maximum error of peak wavelength is ± 1 nm, where error is ± 95% confidence intervals. Coral species include Montipora capitata (n = 49), Porites compressa (n = 75) and Porites lobata (n = 8).
Figure 2. Mean (-) and ± 95% confidence intervals (--) for Kaneohe Bay algae reflectance (A) and fourth-derivative (B) spectra (n = 89). Numbers in (B) indicate wavelengths of major peaks; the maximum error of peak wavelength is ± 1 nm, where error is ± 95% confidence intervals. Algae species include Dictyosphaeria cavernosa (n = 8), Gracilaria salicornia (n = 26), Halimeda sp. (n = 3), Porolithon sp. (n = 15), and Sargassum echinocarpum (n = 44).
Figure 3. Mean (-) and ± 95% confidence intervals (--) for Kaneohe Bay sand reflectance (A) and fourth-derivative (B) spectra (n = 18). Numbers in (B) indicate wavelengths of major peaks; the maximum error of peak wavelength is ± 1 nm, where error is ± 95% confidence intervals. Sand spectra include fine-grained carbonate sand (n = 6), sand interspersed by coral rubble (n = 7), and coral rubble (n = 6).
Figure 4. Linear discriminant functions (LDFs) calculated for Kaneohe Bay spectral data using 7 wavebands at 1 nm resolution. The 2 LDFs maximize the spread of the group mean vectors, and thus are the best linear combinations of the 7 wavebands that separate the 3 groups of coral, algae and sand. When plotted against each other in a scatterplot, the LDFs form the plane of projection that best illustrates the separation of the groups. The 7 wavebands are centered at 400, 427, 452, 462, 494, 526 and 596 nm. See text for details of waveband selection. See Rencher (1995) for details of LDF computation. 3 species of Indo-Pacific corals from the Waikiki Aquarium are also shown in this figure. They are distinguished as coral using the same discriminant functions derived from the Kaneohe Bay data set.
Figure 5. Linear discriminant functions (LDFs) calculated for Kaneohe Bay spectral data using 4 wavebands at 5.5 nm resolution (equivalent to AAHIS spectral resolution). The 4 wavebands are centered at 484, 545, 567 and 584 nm. Note that the absolute values of the functions and the relative distributions of the groups are different than in Fig. 4.
Figure 6. Ground-truth map (A) and classified AAHIS image (B) of a patch reef in Kaneohe Bay, Oahu, Hawaii. Numbers indicate distance in meters. Ground-truth data consists of 2,090 data points (black dots), collected over 144 underwater line transects, sampled at 2 m intervals (36 hours of diving). Line transects were two-dimensionally interpolated to produce this map. The AAHIS image consists of 28,350 data points, approximately 15 times greater spatial resolution than the ground-truth data (2 seconds of flying). The AAHIS image was classified by thresholding the discriminant function values (see Fig. 5). Brown represents coral, green represents algae, yellow represents sand, and blue represents non-reef area.
