Studies using the sensory substitution devices reveal that perceptive activity itself is embodied in a living body capable of movement and possessing its own spatial dimensions. To study the conditions of a prosthetic perception, we developed a minimal device, Tactos, which carries out a coupling between the pen of a graphics tablet and tactile sensory stimulators. This system allows subjects to explore virtual tactile pictures and is intended to give to blind people an access to computer graphics. We will present here experimental results regarding the different aspects of perception using this device.