Examples of GCF functions when using different sensors of the setup depicted in Figure 7. The source is in central position and oriented downward (P4 in Figure 7). Figure (a) shows the GCC-PHAT functions computed at 4 microphone pairs (only a subset of delays is reported in the figure; the maximum possible delay would be 52 samples). Figure (b) shows the GCF map when Pair 1 and Pair 2 are used microphone positions are represented by white semicircles in the GCF maps. Figure (c) depicts the map based on Pair 5 and Pair 6: note how the hyperbolas would cross each other outside the room in the location of an image source. In figure (d), the map resulting from the combination of the 4 pairs is reported. Finally, Figure (e) shows the map obtained when using 7 microphone pairs.