Academic journal article International Journal of Child Health and Human Development

Haptic Presentation of 3D Objects in Virtual Reality for the Visually Disabled

Academic journal article International Journal of Child Health and Human Development

Haptic Presentation of 3D Objects in Virtual Reality for the Visually Disabled

Article excerpt

Introduction

Research concerning the application of haptic force feedback devices for the blind are worth further development as sight cannot be substituted by the auditory information channel alone. Information concerning the living environment can be complemented in this case by the sense of touch.

Furthermore, designing the tactile system dedicated to people with visual disabilities would allow them to access information from the virtual 3D world simply by touching it. The system should consist of three major elements: a camera (which provides information about the distance of obstacles in a scene - a depth map), a computer (the depth map is segmented and the virtual scene is created) and a haptic device (the interface for a tactile presentation of the acquired scene). A haptic device is the interface used for communication between a human and a virtual reality. From the force feedback it produces, a user can feel the shape, density and texture of 3D objects created in a virtual world. The touching experience when using this interface is quite close to reality. Haptic perception incorporates both kinaesthetic sensing, (i.e. of the position and movement of joints and limbs), and tactile sensing, (i.e. through the skin) (1). The most popular haptic devices available are the Phantom Sensable (2) and a range of touching manipulators from Force Dimension (3). The systems define one contact point at a time between the observer and the virtual object. They do not stimulate cutaneous receptors responding to temperature, pressure and pain. The aforementioned devices have great potential and they were considered for use by the blind to familiarize themselves with obstacles inside buildings and for learning new routes and shapes. However, their high cost limits their availability to the average user. Since haptic force feedback technology has entered the world of computer games, a new low-cost device, the Novint Falcon (4) has appeared on the market. Although the device has only 3 degrees of freedom (DOF), compared to that of the Phantom Sensable with 6, this is enough for the 3D object presentation. The aim of this experimental study is to present a prototype system which allows for real scenes to automatically appear in a virtual reality (by means of a time-of-flight 3D camera) and to be accessed in the haptic form by the usage of Novint Falcon.

Related work

Research concerning the application of haptic force feedback, stationary devices for navigating the blind can be divided into two categories: building virtual maps and creating simulators where real obstacles and objects are presented virtually. They are made for learning new routes and it seems they have the potential as a tool which the blind can use to acquire knowledge about a place for an intended first time visit.

The majority of projects are focused on checking if such advanced, yet expensive, devices with a proven quality of performance can be used for such purposes. In the paper (5), two independent studies investigating problems concerning the use of haptic virtual environments for blind people are described. Two devices, a Phantom 1.5 and an Impulse Engine 3000 were used to render virtual textures and 3D objects. Experiments proved that objects rendered by these devices can be effectively perceived by both blind and blindfolded sighted observers. However, the investigated scenarios were very simple. In another publication (6), the usefulness of a haptic force feedback device (the PHANToM) for information without visual guidance was also confirmed. The author tried to find the answers to the following questions: how well blind-folded observers' perception of the roughness of real and virtual sandpaper agree and if the 3D forms of virtual objects could be judged accurately and with short exploration times down to a size of 5 mm. Blind-folded sighted observers judged the roughness of real and virtual sandpapers to be nearly the same. The presented experiments were concluded with a statement that a haptic device can present useful information without vision. …

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