A Haptic Interface for an Indoor-Walk-Guide Simulator

A paper was presented by Yasuyuki Murai and Hisayuki Tatsumi at the 10th International Conference on Computers held on July 12-14 at the University of Linz, Austria. It discussed haptic-interfaces for blind users.

With the development of graphical user interfaces (GUI), a computer user can get access to information on their screen by using a mouse input device instead of typing in text. The blind, however, were unable to benefit from GUI. Elements such as three-dimensional objects and walkthrough features were also inaccessible to them.

The paper presented by Murai and Tatsumi dealt with a haptic pathway simulator that is being developed to help a blind person understand 3D shapes on the computer screen. This device consists of a haptic interface and a computer. The simulator consists of three parts: (1) a Phantom Omni that enables users to touch and manipulate virtual objects, (2) its control software, and (3) the interior layout model.

A stylus, a pen-shaped object with two buttons at the holding position that work like two buttons of a mouse, is attached to the Phantom Omni. The stylus can simulate the feel of moving a white cane that a blind person uses while walking. The 3D movement of the top of the stylus is fed into the input of the 3D model set up in the computer. As the user moves the stylus, he or she receives a tactile feedback from the haptic interface in the form of resisting force along the x, y and z axes. This response, in the form of opposing force, is controlled by the computer. If the user is confronted with a virtual piece of furniture, a strong repulsive force from the floor prohibits further movement. This way, the user can move around the virtual 3D model of a room responding to pseudo-real responses received when moving the stylus. The experience is similar to physically moving around a room using a white cane.

The haptic pathway simulator helps a blind user make a mental map of the layout of the 3D model in the computer. However, there are certain limitations in its use. Using this particular haptic pathway simulator, it is difficult to recognize the real size and texture of objects. Also, if the blind user applies extra force, he or she can easily overcome the resisting force and walk through the object. These problems can certainly be addressed through further development.

Developing assistive technology products based on haptic interfaces for the blind is more than just providing them with a convenient tool to cope with essentially GUI-based software features and programs such as 3D objects. The focus is also not on simply giving them access to information available through such applications. The main aim of developing haptic interfaces devices should be to enable the blind to integrate well into the larger community of computer users with sight.

Assistive technology products based on haptic interfaces enable the blind users to get a clear mental picture of virtual three-dimensional objects, as a sighted user gets.