Fig. 1. Hyperspectral image acquisition system

Fig. 2. Extraction of interest region in apple sample image

Fig. 3. The spectral data of apple samples based on the mean representation before and after SG treatment
(a): Before SG smoothing; (b): After SG smoothing

Fig. 4. The spectral data of apple samples based on the variance representation before and after SG treatment
(a): Before SG smoothing; (b): After SG smoothing

Fig. 5. The change of hue angle of apple samples with the storage days

Fig. 6. The spectral data of apple samples at 675.11 nm based on mean representation

Fig. 7. The Bhattacharyya distance results of hyperspectral information based on mean representation

Fig. 8. Bhattacharyya distance of hyperspectral information based on variance representation

Fig. 9. Bhattacharyya distance results based on 2D hyperspectral information representation with mean and variance