Research On The Key Problems Of Multi-touch Based On Infrared LEDs

Touch control technology is a kind of graph interactive technology whichpermits one or more users operate on the human-computer interaction. As one ofthe human-computer interaction technology, touch has the advantages ofspace-saving, ease to communicate and so on. With the strengthen support ofsoftware platform for touch technology, multi-touch has become the most importantfeature. It is important to research on touch interaction which is adapt to thecomplex environment and satisfy the need of new display technology.As one kind of touch interaction, infrared touch technology has the advantageof low cost, anti-electromagnetic interference, light transmittance high and othermerits, especially the non-contact and non-additional layer, is suitable for stereodisplay of large size, make stereoscopic information high telepresence.The key work we had done is as follows:1.According to the complicated environment about light interference, researchand experiment has been promoted.a)When used in the occasion of serious infrared interference, a multi-touchscheme is put forward, which using galvanometer and strong laser light instead oftraditional infrared array, avoid pollution by environment light.b)In order to solve the problem of noise in the receiving signal caused byenvironment light and fingers shaking, the median average filter combined withweighted recursive filter are chosed to preprocess the touch information, andkalman filter to predict the touch coordinates, restraining the shaking coordinatesand enhancing the robustness of the touch panel.2. Touch coordinates are researched on to solve the touch track is not smooth,resolution is not high enough.a)The principle of centroid is cited to calculate the touch coordinate improvingthe physical resolution.b)We propose B-Spline to forecast the touch coordinates, increasing the touchprecision, and making the output coordinates smoothly.c)Develop a single touch panel to verify the theory above.3. Some new multi-touch technology based on sensor are put forward, to achieve true multi-touch-point instead of false touch points.a)Present a multi-touch technology, which combined liquid crystal light valuewith optical lens.b)A multi-touch technology based on galvanometer is proposed.c) In order to solve the problem of too many transmitters and receivers leadingto the scanning time is too long, we design and realize a47inch multi-touch systemwhich has bilayer structure, a drive and scanning method which takes thetransmitters and receivers in section, so as to improve the response of the touchpanel.