Identification of specific wavelength regions for separating optically similar signals of coral reef benthic compositions

Abstract

The major problem to be overcome in mapping of coral reef ecosystem using remote sensing imagery is the confusion arises between optically similar spectral characteristics of different end-members which are to be used as input for various classification techniques. This work attempts to study in detail the possibilities of identifying the specific wavelength regions for separating optically similar signals of coral reef benthic compositions based on two different hypotheses using derivative analysis. First hypothesis is 1st order derivative analysis can be used to separate optical signatures of different families of corals; and second hypothesis is 2nd order derivative analysis can be used to separate optical signatures of coral species among Acropora family. Results imply that, i) at 515 nm Acropora Muricata, at 585 nm Favia Speciosa & Porites Solida and at 635 nm dead staghorn coral exhibit a negative first order derivative may be the evident that these spectral windows can be helpful in discrimination of corals based on family-wise; ii) at 558 nm Acropora Digitfera, at 565 nm , at 582 nm Acropora Secale, at 595 nm Acropora Varibalis, and at 598 nm Acropora Muricata exhibit a positive second order derivative can be helpful in separating different species among the Acropora family.