Based On Llp Multi-touch System Research And Implementation

As a novel human-computer interactive research field, the multi-touchtechnology can be directly applied to operate the computer by using user’s fingers orother external physical objects. It throws out several traditional input devices includingmouse and keyboard, and focuses on the realization of the “human-centered”human-machine interface. The modern multi-touch systems can be achieved throughdifferent techniques, e.g., DI, LLP. The Laser Light Plane (LLP) method becomes aresearch hotspot because of its application advantages of lost cost, easyimplementation and good scalability.Based on thorough study of the LLP multi-touch principles, this paper designsand implements a human-machine interactive experimental system for multi-touchapplications. The hardware platform of the developed system is built withergonomics’s criterions for design guidance and can be applied for vertical or sittingoperation. The modular structures like touch imaging, projection optics, infraredluminescence and acquisition have been designed and optimized to form a wholesystem and to deduce several significant design criterions and models. For instance,this work has proposes and completes an accurate calibration model for calculating therelative locations among the projector, reflector and display interface. Themulti-objective identification and tracking algorithm has also been studied to convertthe touch information into recognizable image light spots after the data preprocessingof the captured video image. This work achieves the multi-objective identification andtracking by using the background difference algorithm and nearest neighborassociation algorithm, respectively. In addition, the barycenter coordinates method isintroduced to demarcate the camera’s coordinate for achieving accurate correspondingaction point with practical finger’s spots and reducing the possible errors in thedevelopment of the proposed hardware platform.To verify the effectiveness of the developed multi-touch experimental system,several application softwares have been designed and tested based on Flash tools. The test results obtained from different functional tests indicate that the developedmulti-touch experimental system can be used to carry out complex human-computerinteractive operations under multi-person multi-touch situations and reaches the basicdemands from different practical applications.