Ezequiel Roberto Zorzal,  Alexandre Cardoso,  Claudio Kirner,  Edgard A. Lamounier Jr.. 

This paper presents several experiments designed totrigger different events of interaction in AugmentedReality systems. Different types of behaviors andactions were considered, including the positions of themarkers with respect to video projection, collisions ofvirtual objects, distances between different markers,occlusion, spatial orientation of the markers and voicecommands.

http://www.lbd.dcc.ufmg.br/colecoes/wrva/2009/0028.pdf

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