Detection of stressed oil palms from an airborne sensor using optimized spectral indices

作者：Shafri Helmi Zulhaidi M^*; Hamdan Nasrulhapiza; Anuar Mohamad Izzuddin

来源：International Journal of Remote Sensing, 2012, 33(14): 4293-4311.

DOI：10.1080/01431161.2011.619208

Existing vegetation indices and red-edge techniques have been widely used for the assessment of vegetation status and vegetation health from remote-sensing instruments. This study proposed and applied optimized Airborne Imaging Spectrometer for Applications (AISA) airborne hyperspectral indices in assessing and mapping stressed oil palm trees. Six vegetation indices, four red-edge techniques, a standard supervised classifier and three optimized AISA spectral indices were compared in mapping diseased oil palms using AISA airborne hyperspectral imagery. The optimized AISA spectral indices algorithms used newly defined reflectance values at wavelength locations of 734 nm (near-infrared (NIR)) and 616 nm (red). The selection of these two bands was based on laboratory statistical analysis using field spectroradiometer reflectance data. These two bands were then applied to the AISA airborne hyperspectral imagery using the three optimized algorithms for AISA data. The newly formulated AISA hyperspectral indices were D2 = R-616/R-734, normalized difference vegetation index a (NDVIa) = (R-734 - R-616)/(R-734 + R-616) and transformed vegetation index a (TVIa) = ((NDVIa + 0.5)/(abs (NDVIa + 0.5)) x [abs (NDVIa + 0.5)](1/2). The classification results from the optimized AISA hyperspectral indices were compared with the other techniques and the optimized AISA spectral indices obtained the highest overall accuracy. D2 and NDVIa obtained 86% of overall accuracy followed by TVIa with 84% of overall accuracy.

• 出版日期2012