Application of a Spectroscopic Analysis-Based Portable Sensor for Phosphate Quantitation in Hydroponic Solutions

Table 3

Performances of multiple regression models used for predicting phosphate ion concentration.

Regression model	Preprocessing	RMSEC		Regression model	Preprocessing	RMSEC
		RMSEP				RMSEP
PLSR	No (raw data)	18.20	0.88	PCR	No (raw data)	17.10	0.90
		20.20	0.87			21.10	0.84
	Smoothing	14.89	0.92		Smoothing	17.10	0.88
		18.00	0.88			20.20	0.86
	Smoothing + SNV	18.30	0.88		Smoothing + SNV	23.60	0.81
		26.90	0.75			28.60	0.71
	Smoothing + MSC	27.10	0.74		Smoothing + MSC	27.30	0.75
		30.10	0.70			29.50	0.72
	1^st derivative	18.50	0.88		1^st derivative	18.60	0.89
		22.50	0.83			23.50	0.84