SheeTra allows for tracking of physical sheets on multi-touch tables. The project is written in C++ and contains two different trackers: A shadow tracker for markerless tracking using the infrared camera inside the table and a markerbased tracker using the Studierstube Tracker and cameras mounted above the table.

Shadow Tracking: (left) input image recognized by infrared camera; (right) output of harris corner detection.

Marker Tracking: (left) tabletop setup; (right) example of a paper sheet arrangement, including the calculated z-indeces.

This physical sheet data is the foundation of a project with two other groups to explore interaction with physical and digital sheets on tabletops.

SheeTra was developed together with Jan Riemann, Andre Wisplinghoff and Maik Thöner. It was part of the lecture Projektpraktikum Telekooperation at TU Darmstadt during the winter term 2009/2010. The project was supervised by Jürgen Steimle and Mohammadreza Khalilbeigi.