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Interactive touch board using IR camera

This paper presents a novel and cost-effective approach to convert any projected display on a flat surface into interactive touch board, through the aid of computer vision techniques. An interactive touch board is similar to that of a touch screen available in mobile phones and tablets, but then uses a special stylus for its input and a LCD projector for projecting the display on the surface. Commonly used techniques fall under any of the four categories – Resistive, Capacitive, Electromagnetic and Optical. The paper proposes a method pertaining to the optical technique – involving an infrared camera, a light emitting stylus and an image processing algorithm to determine the position pointed by the user. The stylus has an infrared LED at its tip and capable of producing a tiny spot of light on the projected surface, which is invisible to human eyes. But an IR camera with IR pass filter can be used to capture the light spot and can be processed further.

This is the principle technique behind the proposed method. The image from the camera is processed using an algorithm, which determines the coordinates of the IR light. This obtained position along with some calibration parameters is sufficient to calculate the mouse cursor coordinates and thus the cursor can moved to the intended position. The whole of the image processing algorithm has been implemented using the NI LabVIEW and its associated Vision and Motion toolkits. Further, the paper deals with the study of potential applications in education and scientific research.