Paper Reading #14: Bonfire: a nomadic system for hybrid laptop-tabletop interaction

Comments
Shena Hoffman -http://csce436-hoffmann.blogspot.com/2011/03/paper-reading-14-eden-supporting-home.html
Vince Kocks - http://vincehci.blogspot.com/2011/03/paper-reading-14-sensing-foot-gestures.html

Reference Information
Title: Bonfire: a nomadic system for hybrid laptop-tabletop interaction
Authors: Shaun K. Kane, Daniel Avrahami, Jacob O. Wobbrock, Beverly Harrison, Adam D. Rea, Matthai Philipose, Anthony LaMarca
Presentation Venue: UIST 2010: 22nd annual ACM symposium on User interface software and technology; October 4-7, 2009; Victoria, British Columbia, Canada

Summary
In this paper the researchers discuss Bonfire, a mobile computer system that projects an interactive display on either side of the computer through the use of two projectors and cameras mounted on a laptop. Bonfire can respond to many things in its views. It can copy a picture from a textbook onto the computer, recognize when the user places certain objects down in its view (like headphones or food) and react appropriately to the objects (pause a song until the head phones are picked back up or calculate the user’s caloric intake).

The interactions can be broken down into two main categories: explicit interactions where the user puts an object in Bonfire’s view to use the object in some way, and implicit interactions where the system collects and reports data about the user based on the objects it sees. Bonfire can also provide the user with more screen space by display images or other information on the projected views. However, the focus is on images, because text is not well represented with the projectors.

To identify the objects in its view, Bonfire captures an image of the tabletop when it starts up and identifies the space as the background. To identify objects it uses an object recognition algorithm that employs color histogram matching. When Bonfire cannot recognize an object, it includes it in the background but keeps a list of these objects so that the user can use them if he desires.

Being an interactive system, Bonfire tracks the motion of the user’s fingers by first identifying the user’s skin color at startup, detecting that color as part of the hand during interaction and then identifying the user’s fingers through geometric features described in a previous work. The system supports tapping, dragging, crossing and flicking.

Image taken from the paper: Picture of the Bonfire set up

Discussion
I liked how this paper was presented. Within the first couple of pages the authors provided the readers with a scenario of a girl using her laptop at a coffee shop to help the readers better understand the system. Further on in the paper they provided many more examples on how Bonfire works. They also estimated what the price of the projectors will be by the time the product is in production ($400-$500), which is something I haven’t seen before in a paper.

While I do think this system would have a lot of great uses, I’m not so sure it will be widely used due to how large the system is and how expensive the projectors will be. However, I do like where they’re going with this system. I think Bonfire would be a great study aide and really useful for people with netbooks who need more space.

The researchers mention that for future works they would like to try using more cameras to better see what the user does. They would also like to enhance the system so that multiple people can work together through the system and have uses for overlapping camera and projector views.