Live Coral Cover Index Testing and Application with Hyperspectral Airborne Image Data

Remote Sensing

Karen E. Joyce²  Stuart R. Phinn¹ 

[1] Centre for Spatial Environmental Research, School of Geography, Planning, and Environmental Management, University of Queensland, St Lucia, QLD 4072, Australia; E-Mails:;Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina Campus, Darwin, NT 0810, Australia

关键词: live coral;    spectral index;    band ratios;    image processing;    hyperspectral;    field survey;    remote sensing;    CASI;   

DOI  :  10.3390/rs5116116

来源: mdpi

【 摘 要 】

Coral reefs are complex, heterogeneous environments where it is common for the features of interest to be smaller than the spatial dimensions of imaging sensors. While the coverage of live coral at any point in time is a critical environmental management issue, image pixels may represent mixed proportions of coverage. In order to address this, we describe the development, application, and testing of a spectral index for mapping live coral cover using CASI-2 airborne hyperspectral high spatial resolution imagery of Heron Reef, Australia. Field surveys were conducted in areas of varying depth to quantify live coral cover. Image statistics were extracted from co-registered imagery in the form of reflectance, derivatives, and band ratios. Each of the spectral transforms was assessed for their correlation with live coral cover, determining that the second derivative around 564 nm was the most sensitive to live coral cover variations(r² = 0.63). Extensive field survey was used to transform relative to absolute coral cover, which was then applied to produce a live coral cover map of Heron Reef. We present the live coral cover index as a simple and viable means to estimate the amount of live coral over potentially thousands of km² and in clear-water reefs.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland