Table 1.

Comparison of ${\ell }^0\mathrm{-}\mathrm{sparseness}$ (in percent of non-zero pixels), ${\ell }^1\mathrm{-}\mathrm{sparseness}$ (cf. (4)), reconstruction quality in terms of SNR, and runtime for ${\ell }^1\mathrm{-}\mathrm{sparse}$ NMF [13] and $\mathrm{NMF}{\ell }^0$-W. SNR^⁎ denotes the SNR value for ${\ell }^1\mathrm{-}\mathrm{NMF}$, when the same ${\ell }^0\mathrm{-}\mathrm{sparseness}$ as for $\mathrm{NMF}{\ell }^0$-W is enforced.

Method	${\ell }^0$ (%)	${\ell }^1$	SNR (dB)	SNR⁎ (dB)	Time (s)
${\ell }^1\mathrm{-}\mathrm{NMF}$	52.4	0.55	15.09	14.55	2440
$\mathrm{NMF}{\ell }^0$-W	33	0.55	15.07	–	186
${\ell }^1\mathrm{-}\mathrm{NMF}$	43	0.6	14.96	14.31	2495
$\mathrm{NMF}{\ell }^0$-W	25	0.6	14.94	–	164
${\ell }^1\mathrm{-}\mathrm{NMF}$	18.6	0.73	14.31	13.52	2598
$\mathrm{NMF}{\ell }^0$-W	10	0.73	14.33	–	50