RENCI Vis Group Multi-Touch Blog

Developing multitouch hardware and applications for research and experimentation.

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UNC-Charlotte Engagement Site Takes Delivery of Multi-Touch Table

27 July, 2009 (11:53) | UNC-Charlotte Multi-Touch Table


RENCI's Jason Coposky experiments with the Urban Growth Model as UNC-C Assistant Professor Zachary Wartell, Ph.D. and Ph.D. student Dong Jeong look on.

Jason Coposky and Warren Ginn from RENCI Europa delivered UNC-Charlotte’s Multi-touch Table to the Charlotte Visualization Center last week. Dubbed the Urbanization Explorer Touch Table, the device’s first role will be to display the Urban Growth Model, developed by the Center for Applied Geographic Information Science (CAGIS) and UNC-Charlotte’s Urban Institute. By accessing historical patterns of growth in the region, this application will provide forecasts on how much growth is expected to take place based on these historical patterns. Using satellite imagery for the 24-county region around Mecklenburg, for four time periods: 1976, 1985, 1996 and 2006, the Urban Growth Model tracks the advance of impervious surfaces, a key indicator of development, in expansion across the area since 1976, and estimates the extent of urbanization through 2030. With interfaces developed by collaborators at the Charlotte Visualization Center, multiple users will be able to select areas of interest, zoom, pan, and navigate the colorful, large-format maps using only their fingertips and on-screen digital tools.


Frame assembly of table without the touch surface assembled. Note the single Prosilica amera in the middle and the 4 illuminators that supplement the edge illumination (because of the camera's wide-angle lens). This camera will eventually be replaced by 4 smaller Firefly cameras, which will improve touch performance and accuracy.

First introduced at North Carolina State University‚Äôs Institute for Emerging Issues annual forum this past Februrary, this multi-touch table represents the next leap in performance in touch tracking. As opposed to the previous Direct Illumination (DI) technique employed in the original table, this table employs Diffused Surface Illumination (DSI). By employing a sheet of Cyro Acrylite EndLighten with polished edges and LED Edge-View Ribbon Flex from Environmental Lights, we’ve been able to distribute the IR illumination more evenly.


Infrared LEDs on a trip from Environmental Lights is applied to the inside perimeter of the frame where the polished Endlighten acrylic sheet will be installed.

For the projection surface we’re using a thin (3mm) sheet of Acrylite RP 7D513 rear projection acrylic. This works out well since the thn sheet protects the more expensive Endlighten material and the projection surface has a nice touch.


Completed UNC-C table in the Europa lab.


Setting up the table at the Charlotte Vis Center.

« Experiments with EndLighten and IR LED Edge-View Ribbon


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