Table 2.

Cluster characteristics for the different clustering approaches

		Without $D^{*}$				With $D^{*}$
		GMM		GHMRFM		GMM		GHMRFM
Class label l		1	2	1	2	1	2	1	2
P(l) (%)		65	35	65	35	58	42	60	40
	D ($\mathrm{\mu }{m}^2$/ms)	0.65	0.73	0.62	0.78	0.65	0.72	0.61	0.80
${\mathit{\mu }}_l$	f (%)	8.8	1.0	9.2	1.0	9.0	1.4	9.5	1.3
	$D^{*}$ ($\mathrm{\mu }{m}^2$/ms)	—	—	—	—	10.9	4.6	11.7	4.1

Note: P(l) is the prior class probability, i.e. the size of class l, and ${\mathit{\mu }}_l$ is the mean vector of class l contain values of D, f and $D^{*}$.