A robust spectral angle index for remotely assessing soybean canopy chlorophyll content in different growing stages

Table 6 The relationships between the UAV-based Chl VIs and Chl-D (Dualex units) shown in Fig

VI	Equation	R²	MAE	RMSE
VNAI	(e1) Chl-D = 0.2622 × VNAI – 53.473	0.77	2.73	3.54
VNAI	(e2) Chl-D = 1.3074 × EXP (0.0097 × VNAI)	0.74	3.00	3.79
PSND	(e3) Chl-D = 90.91 × PSND – 46.337	0.29	4.91	6.18
PSND	(e4) Chl-D = 1.212 × EXP (3.763 × PSND)	0.27	4.98	6.37
TCARI/OSAVI_RE	(e5) Chl-D = –66.358 × TCARI/OSAVI_RE + 47.353	0.67	3.33	4.21
TCARI/OSAVI_RE	(e6) Chl-D = 56.11 × EXP (–2.561 × TCARI/OSAVI_RE)	0.67	3.28	4.23
NDRE2	(e7) Chl-D = 42.353 × NDRE2 + 6.2227	0.53	4.18	5.03
NDRE2	(e8) Chl-D = 11.158 × EXP (1.6807 × NDRE2)	0.51	4.22	5.17

Equations e1, e3, e5, and e7 were used for the validation of the Chl models. R² coefficient of determination, MAE mean absolute error, RMSE root-mean-square error

ISSN: 1746-4811