Paper Reading #15:Interactions in the air: adding further depth to interactive tabletops

Comments
Cindy Skach
Evin Schuchardt

Reference Information

Title: Interactions in the air: adding further depth to interactive tabletops

Authors: Otmar Hilliges  Microsoft Research Cambridge, Cambridge, United Kingdom 
              Shahram Izadi  Microsoft Research Cambridge, Cambridge, United Kingdom 
              Andrew D. Wilson  Microsoft Research, Redmond, WA, USA 
              Steve Hodges  Microsoft Research Cambridge, Cambridge, United Kingdom 
              Armando Garcia-Mendoza  Microsoft Research Cambridge, Cambridge, United Kingdom 
              Andreas Butz  University of Munich, Munich, Germany 

Presentation Venue: UIST 2009: 22nd annual ACM  symposium on User interface software and technology; Date: 2009;
Location: New York, NY, USA

Summary
This paper deals with interactive surfaces. The authors want to improve interaction with tabletops by allowing users to utilize the space above the surface, and hence intuitively manipulate three dimensional objects. The authors have implemented two prototype systems which I will describe. These prototypes were done while keeping in mind the need to enable richer depth-based interactions, without compromising an integrated hardware form factor. Two rear projection-vision tabletops are used. Both use special projection screen materials to allow sensing at significant depths beyond the display. Existing and new computer vision techniques are used to sense hand gestures and postures above the tabletop, which can be used alongside more familiar multi-touch interactions.

The first system uses a diffuser to extend the input space so that it can recognize what the users are gesturing.
The second system uses a shadow-based technique with two implementations. In the first they use a shadow-mapping technique. In the second,  they generated a shadow map for all the virtual objects and stored each pixel’s z-value to be compared when determining how a user is manipulating an object. This provides useful feedback for the user. 

Hundreds of users, all colleagues of the authors, have interacted with the system and helped the authors determine that without the shadows being displayed, the users had trouble learning how to work the system on their own. In additioan, users attempted to grab the objects only to find out that grabbing was not supported by the system.
 

 

Discussion
This paper presented potential models to implement a more seemless experience when manipulating 3D objects. The user studies are not elaborate, however it does seem they have been able to pinpoint areas on which to improve thanks to their colleagues, and some of their debugging techniques. I do think enhancing tabletop interfaces is important. It decreases any learning curve by using familiar gestures to manipulate 3D objects.