The Effect that the Visual and Haptic Problems Associated with Touching a Projection Augmented Model Have on Object-Presence

Abstract

A projection augmented model (PA model) is a type of haptic augmented reality display. It consists of a real physical model, onto which a computer image is projected to create a realistic looking object. Thus, a PA model creates the illusion of actually being the object that it represents, as opposed to a white model and a projected image. Users can physically touch the surface of a PA model with their bare hands, which has experiential value for the types of applications for which they are being developed. However, the majority of PA models do not provide haptic feedback for material properties such as texture, and hence feel incorrect when they are touched. In addition, most PA models are front-projected which means the projected image appears on the back of the user's hand, and their hand casts a shadow on the display. Previous research has found that touching this type of PA model reduces a user's sense of object presence. The empirical study reported in this paper investigated which of the problems had a greater effect on object presence. It was found that object presence was significantly higher when correct haptic feedback for material properties was provided; however eliminating the visual projection problems rarely affected object presence. These results have implications for the direction in which PA model technology should be developed. They also have implications for theory on how the haptic and visual senses contribute to a person's sense of object presence, and indeed presence. Background: Projection Augmented ModelsA projection augmented model (PA model) is a type of projection based haptic augmented reality display. It consists of a physical three-dimensional model, onto which a computer image is projected to create a realistic looking object. For example, the PA model in Figure 1 consists of smooth white plaster models of various objects that are commonly found in a garden shed (Bennett & Stevens, 2005). The image projected onto these objects provides color and visual texture, which makes them appear to be made from different materials. The PA model shown in Figure 1 is front-projected. However, if a semi-*Correspondence to emily.bennett@port.ac.uk.

Haptic Augmented Reality: Taxonomy and an Example of Stiffness Modulation

“…Another example is the projection augmented model. A computer-generated image is projected on a real physical model to create a realistic-looking object, and the model can be touched by the bare hand (e.g., see Bennett & Stevens, 2006). Since the material property (e.g., texture) of the real object may not agree with its visually augmented model, haptic properties are usually incorrectly displayed in this application.…”

Multisensory Softness

“…A typical example is tangible AR, where a handheld real prop is used as a tangible interface in visually mixed environments (e.g., the MagicBook in Billinghurst et al (2001)). Another example is the projection augmented model, where a computer-generated image is projected onto a real physical object that is explored by the bare hand (Bennett and Stevens 2006). In these cases, variation of haptic properties is regarded as less important.…”