Multi-touch interaction for table-top display

In this paper, we describe a system of multi-touch tabletop display and its control algorithm for Google-earth (TM) that utilizes hand gesture as mouse free interaction. The system adopts well known FTIR technique. The hand gesture of necessary instruction is predefined according to the number, position, and movement of the fingertips which are obtained from multi-touch of a single user. The system consists of a beam-projector and an acrylic screen attaching infrared LED as light source, and an infrared camera for capturing the fingertip image. Input image is preprocessed with simple morphological method to remove the noise and to determine the fingertip region. In recognition process, gesture commands are recognized by comparing the preprocessed image with predefined gesture model of fingertips. In detail, firstly the number of the spot; fingertip mark, angles among the spots, and Euclidean distance between two spots are calculated, and then the values are compared with the information of the model. The effectiveness of the system can be proved through the experimental results.