Fig. 1. Hyperspectral imaging system

Fig. 2. Automatic ROI extraction in hyperspectral images

Fig. 3. Average reflection informations of carpopodium, sarcocarp and background

Fig. 4. Stacking ensemble learning process
(a): Training and prediction models for metamodels; (b): General flowchart

Fig. 5. Flow chart of fast and non-destructive grading model of black goji berry

Fig. 6. Spectral curves of black goji berries before and after pretreatment
(a): Raw spectra of carpopodium; (b): Raw spectra of sarcocarp; (c): Spectra of carpopodium after FD treatment; (d): Spectra of sarcocarp after FD treatment; (e): Average spectra of different grades of black goji berrycarpopodium after FD treatment; (f): Average spectra of different grades of black goji berrysarcocarp after FD treatment

Table 1. Anthocyanin content of four grades of black goji berry

Table 2. PCA-based modeling results

Table 3. Modeling results of Stacking ensemble learning