In our days the concept of "mobile office", i.e. solutions by which an employee of a company can do his work anywhere under any circumstances, is becoming more and more popular. For works requiring computer we've been recently using portable computers which have the disadvantage of considerable weight even in case of smaller devices. By the advance of technology, new devices with acceptable size and weight have become available. However, text input into these devices is quite uncomfortable so besides writing some emails they are not suitable for more complex tasks.
Integration of virtual keyboards into these kinds of mobile devices can be a good solution to the problems mentioned above. Virtual keyboards are a projection of a keyboard's image to any kind of flat surface on which data input is realized in some ways. In the thesis we can follow the design and construction process of a camera-based virtual keyboard system using laser technology.
Immediately above the projected keyboard image, in parallel, the device will also project an invisible infrared laser plane of a few millimeters which plays an important role in the keystroke detection. When the user "presses" a key, his finger breaks this infrared laser plane which thus becomes visible for the camera of the processing system. The bright light-spot appearing on the camera image assigns the location of the keystroke in the camera coordinate system. With further processing of this information the system can generate the appropriate event according to the given keystroke.