Study And Implementation Of The Large-size Infrared Touch Multi-point Recognition Technology

Touch technology is a new way of human-computer interaction in recent decades,with its charateristics of intuitive and efficient,smooth and natural,it has gradually won the favour of people.With the continuous development of touch technology,touch screen is towards small size to big size,from traditional can only support a single point of touch to the direction of multi-touch support.Among the current number of touch technology,suitable for large size liquid crystal display is infrared touch technology and optical image sensor technology. Infrared compared with optical,infrared touch screen with its low cost,strong environment adaptability,easy installation and maintenance,longer life,more identification of touch points,and many other advantages,has been preferred in the design and production of large size touch screen.Currently,the hardware technology of infrared touch technology is already quite muture,the main factors which restrict the development of the infrared touch technology is algorithm and software.In this paper,the hardware and algorithm of the large-size infrared touch multi-point recognition technology have been studied and implementated,especially in the research process of the algorithm,I find that the traditional infrared multi-point positioning technology uses only part of the light path data for point positioning,such as only uses obscured light path data for multi-point orientation,does not consider the effect caused by unobstructed light path to the point coordinates;The light path data of infrared touch screen is in the discrete state(there are gaps between the infrared diodes),so the location of the output multi-point is in jump condition,how to make the multi-point trajectory smooth,is directly related to the touch feeling of the touch screen;Infrared touch screen is a kind of non-contact touch device,so vulnerable to accidental touch disturbance caused by insects and so on,and if there are a few infrared diodes damaged,it will also cause the touch screen unable to response nomally.In order to solve the key technical difficulties,this paper has carried out the following innovations:1)A kind of multi-point positioning technology based on the global light path information has been designed and implemented to improve the points positioning accuracy and the correct rate of points recogniton and reduce the rate of ghost points of the infrared touch screen.2)A kind of multi-point trajectory smoothing technology based on Kalman filter has been designed and implemented to reduce the jitter and sawtooth of the infrared touch screen’s handwriting trajectory and enhance the user’s touch feeling.3)A kind of touch screen dead points restraining technology based on the mechanism of the global light path imformation dynamic feedback and monitoring has been designed and implemented to improve the touch screen’s ability of anti interference such as error recognition and false touch.