EXTRACTION OF A PERSONS HANDSHAPE FOR APPLICATION IN A HUMAN INTERFACE

This paper proposes a human interface where a novel input method is us ed to substitute conventional input devices. It overcomes the deficien cies of physical devices, as it is based on image processing technique s. The proposed interface is composed of three parts: extraction of a person's handshape from a digitized image, detection of its fingertip, and interpreta tion by a software application. First, images of a poi nting hand are digitized to obtain a sequence of monochrome frames. In each frame the hand is isolated from the background by means of gray- level slicing; with threshold values calculated dynamically by the com bination of movement detection and histogram analysis. The advantage o f this approach is that the system adapts itself to any user and compe nsates any changes in the illumination, while in conventional methods the threshold values are previously defined or markers have to be atta ched to the hand in order to give reference points. Second, once the h and is isolated, fingertip coordinates are extracted by scanning the i mage. Third, the coordinates are inputted to an application interface. Overall, as the algorithms are simple and only monochrome images are used, the amount of processing is kept low, making this system suitabl e to real-time processing without needing expensive hardware.