The replicates for each sample were averaged prior to further analysis. Matlab® (ver. 7.6, The MathWorks Inc., Natick, MA) was used for the analysis of the spectral data. Fig. 3 represents the spectral reflectance of the four bands using the box-and-whisker plots. Some of the outlier samples (indicated as red ‘+’ mark in the box plot) were removed from the dataset that was used for the classification. The outlier was any value that was outside the interquartile ranges. Thus, the total number of samples in the reduced dataset representing unripe, ripe, and overripe oil palm FFB class was 39, 40, and 41, respectively.