THE USE OF LABORATORY SPECTROSCOPY TO ESTABLISH PTERONIA INCANA SPECTRAL TRENDS AND SEPARATION FROM BARE SURFACES AND GREEN VEGETATION

Abstract

ABSTRACT Spectral trends of Pteronia incana, an unpalatable invader shrub, and its separation from bare surfaces and green vegetation are examined using a high resolution spectrometer. As a technique that provides reliable reflectance values, direct spectroscopy was used to measure spectral reflectance in the field and laboratory at 0.45µm to 0.88µm wavelengths. The reflectance of P. incana leaves and branches of varying proportions was compared using laboratory spectroscopy and the effect of increasing leaf percentage in branch samples was determined by performing regression analyses at 0.55µm, 0.68µm and 0.88µm. The Student's t-test was used to establish whether the difference between the mean reflectance of the respective surfaces was statistically significant. Results showed a strong correlation between average spectral measurements and increasing percentage of leaves. Whereas separability between the respective surfaces was achieved in the near infrared band, a consistent spectral trend showing a clear distinction between the surfaces was achieved using the first order derivative.