Siniˇ sa Kolari´ c Towards direct spatial manipulation of virtual 3D objects using visual tracking and gesture recognition of unmarked hands MSc Thesis Thesis presented to the post-graduate program in Computer Science of the Department of Computer Science, PUC-Rio as partial fullfillment of the requirements for the degree of Master in Computer Science. Adviser : Prof. Marcelo Gattass Co–Adviser: Prof. Alberto Barbosa Raposo Rio de Janeiro March 2008