Table 1.

Results of the optimization of $\sigma$ on the root-mean-square error (RMSE) between the predicted thresholds and the thresholds from the experiment for the 4 models.

	${\sigma }_{\mathit{opt}}$	RMSE	error %
Model 1	/	/	/
Model 2	0.118	90.06	30.32
Model 3	0.539	13.71	11.04
Model 4	1.153	0.412	1.74

The error is also expressed as the percentage error for visualization. Optimization with model 1 is not possible.