Fast Discrimination of Apple Varieties Using Vis/NIR Spectroscopy

Figures & data

Figure 1 Original reflectance spectra for one apple (325–1075 nm) (mean value of 30 scans).

Figure 2 Near infrared reflectance spectra of three different apple varieties.

Table 1 PCs and reliabilities

Principal components	PC1	PC2	PC3
Cumulative reliabilities	68%	98%	99.298%

Figure 3 Principal component scores image (PC1 × PC2) of three species of apples.

Figure 4 Original spectra of samples before wavelet transform.

Figure 5 Characteristic information of spectra after wavelet transforms.

Table 2 Result of prediction for 15 unknown samples by BP-ANN model

Sample no.*	Standard value	Calculated value	Sample no.*	Standard value	Calculated value	Sample No.*	Standard value	Calculated value
(1)	1	1.00407	(6)	2	2.00162	(11)	3	2.99770
(2)	1	1.00292	(7)	2	2.01777	(12)	3	2.99931
(3)	1	1.00492	(8)	2	1.96897	(13)	3	2.99976
(4)	1	1.00943	(9)	2	2.00307	(14)	3	3.00000
(5)	1	1.00198	(10)	2	1.99830	(15)	3	2.99923
*: (1–5): Red Delicious apples; (6–10): Copefrut Royal Gala apples; (11–15): Fuji apples.