Experiments were also performed to test the performance of
the system and the coherence pruning when experiencing sound
from multiple targets. Figure 10 shows box plots of the angular
error in the cases of two, three and four targets. In these plots,
the target number n is the target that is localized after n − 1
pruning iterations. In all experiments up to three targets were
localized with a good accuracy. However, the precision dropped
significantly after the third pruning step resulting in poor measurements
for the direction of the fourth target. The number of
existing targets did not have a major effect on the localization
for the first three dominant targets, with only a minor increase
in the number of outliers.