Puppeteered rain: interactive illusion of levitating water drops by position-dependent strobe projection

Light projection onto falling water produces distinct and impressive experience which is suitable for entertainment and advertising installations in public spaces [Barnum et al. 2010; Eitoku et al. 2006]. One of popular and classical techniques used in illuminating water for such purposes is strobe lighting, which presents optical illusion of levitating --- or slowly falling or rising --- water drops depending on the relation between water dropping and strobe lighting frequencies (e.g. [Pevnick 1981; Rosenthal 1984]).