VIsual DEcoder by Touch (ViDeT) virtual reality for the visually impaired This is a three year (1996-99) reserch project of DEIS (Dept. of Electronics, Computer Science and Systems), DIEM (Dept. of Mechanics) and DM (Dept. of Mathematics) supported by University of Bologna and also by ASI, CNR and Ser.In.Ar.. Project coordinator: Prof. Claudio Bonivento ich [...] sehe mit fühlendem Aug, fühle mit sehender Hand. (J.W. v. Goethe, Römische Elegien) I [...] see with feeling eyes, I feel with seeing hands.

The VIDET (VIsual DEcoder by Touch) project aims to the design of a device converting depth information about a visual scene, into tactile information for a visually impaired user.The steps of this conversion are:

• camera pair (mounted on the shoulders of the user) captures two images of the scene;
• a portable computer extracts depth information from the images and interpolates it into a surface;
• this virtual surface, suitably scaled, is presented to the user by means of a wire-operated force-feedback robotic device (the WireMan). The user's finger is lodged in a thimble at the end of three wires coming out of a knapsack; these react to movement only when the finger hits the virtual surface.

The effect is that the user feels a "bas-relief" model of the scene. A most likely added performance will be colour rendering. Eventually, also global acoustical information ("virtual rain") will be added.

Starting from an initial idea of M. Ferri, encouraged by T. Salmon Cinotti, C. Bonivento and G. Vassura, VIDET is coming into shape by a strongly interdisciplinary effort based at DEIS (directed by G. Falciasecca) in its Laboratory of Automation and Robotics (LAR). The advice and help of the APH (Handicap Project Association) of Bologna is gratefully acknowledged.

The interdisciplinary nature of the project and its complexity impose us to divide the amount of work and to set up a certain number of reseach groups, each of them with the attempt to develop a certain aspect of the project itself. During the last three year four groups were mainly involved in the reseach activity. Their research fields were:

• Acquisition and depth calculation;
• Surface interpolation;
• Mechanical device;
• Control algoritms;
• Colour rendering;
• Experimental activity.

The complete bibliografy can be found here.

At the moment, the haptic interface is not integrated in a really portable device. Because of the great computational power that the vision algorithm needs, the acquisition and depth calculation software and the control software are handled by two distinct workstations. The image excange between the WireMan and its "eyes" is implemented over a TCP/IP network. With this actual configuration, we can extend the application area of the device to the exploration of remote environment using a normal internet-intranet connection.

You can also download some videos in MPEG format that describe the structure and behaviour of the haptic interface.

• Video 1: in this video a general overview of the system and its behaviour in free space are given.
• Video 2: in this video the interaction with a virtual wall is described.
• Video 3: in this video an example of interaction with moving object is given.