Fig. 2:

Localization of brain-activity sources from EEG data is an SNL problem. The image in the top left corner shows the position of three sources in a human brain, situated in the occipital (θ1), temporal (θ2) and frontal (θ3) lobes. The remaining three images show the EEG data corresponding to each of these sources, obtained from 256 sensors located on the surface of the head (see Section IV-B for more details).