Table 1.

The optimal parameters for each PPG template obtained using the interior point method.

Template	$a_1$	${\theta }_1$	$b_1$	$a_2$	${\theta }_2$	$b_2$	MSE	r
Excellent	1.0000	− 1.5161	0.6303	0.1999	0.8186	1.0225	0.001	0.995
Acceptable	0.7303	− 1.5510	0.7283	0.5291	− 0.2553	1.2271	0.003	0.988
Unfit	0.9288	− 1.0241	1.2055	0.4916	2.2684	1.2055	0.017	0.851

${\theta }_1$ and ${\theta }_2$ are the position of the peak centers of the first Gaussian function and the second Gaussian function, respectively; $a_1$ and $a_2$ are the peak heights, $b_1$ and $b_2$ are the standard deviations of the first and second Gaussian functions; respectively. MSE is the mean square error, and r is the correlation coefficient. An excellent PPG template means that the systolic and diastolic waves in pulse are salient. An acceptable PPG template means that the systolic and diastolic waves are not salient, but heart rate can be determined. Unfit means that the heart rate cannot be determined and the systolic and diastolic waves cannot be distinguished.