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Journal of Spectroscopy
Volume 2018 (2018), Article ID 8316918, 8 pages
https://doi.org/10.1155/2018/8316918
Research Article

The Impact of Simulated Spectral Noise on Random Forest and Oblique Random Forest Classification Performance

School of Agriculture, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville P/Bag X01, Pietermaritzburg 3209, South Africa

Correspondence should be addressed to Na’eem Hoosen Agjee; moc.liamg@2neejga

Received 30 August 2017; Accepted 9 January 2018; Published 13 March 2018

Academic Editor: Javier Garcia-Guinea

Copyright © 2018 Na’eem Hoosen Agjee et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Hyperspectral datasets contain spectral noise, the presence of which adversely affects the classifier performance to generalize accurately. Despite machine learning algorithms being regarded as robust classifiers that generalize well under unfavourable noisy conditions, the extent of this is poorly understood. This study aimed to evaluate the influence of simulated spectral noise (10%, 20%, and 30%) on random forest (RF) and oblique random forest (oRF) classification performance using two node-splitting models (ridge regression (RR) and support vector machines (SVM)) to discriminate healthy and low infested water hyacinth plants. Results from this study showed that RF was slightly influenced by simulated noise with classification accuracies decreasing for week one and week two with the addition of 30% noise. In comparison to RF, oRF-RR and oRF-SVM yielded higher test accuracies (oRF-RR: 5.36%–7.15%; oRF-SVM: 3.58%–5.36%) and test kappa coefficients (oRF-RR: 10.72%–14.29%; oRF-SVM: 7.15%–10.72%). Notably, oRF-RR test accuracies and kappa coefficients remained consistent irrespective of simulated noise level for week one and week two while similar results were achieved for week three using oRF-SVM. Overall, this study has demonstrated that oRF-RR can be regarded a robust classification algorithm that is not influenced by noisy spectral conditions.