The main purpose of this study is to explore the interaction between a musical application and a tabletop display. This is achieved by exploring areas such as Human Computer Interaction (HCI), Computer Graphics and Image Processing. This project details the interaction paradigm of playing piano using the pressure of fingers on a rear-projected surface. This was achieved by developing a graphical piano keyboard, an audio synthesize, and a fingertip recognition software. Usability testing showed that the quality of the fingertip spotting is not accurate enough to perform piano-like music. Latency between a pressure and the music is also an issue. However, the interaction paradigm with the tabletop display please users, so that they would be interested by other application taking advantage of this system. Nevertheless, this study identified areas for improvements that could enhance the system.