Design And Implementation Of Multiple Touch Screen Based On Infrared Light Technology

Multiple touch technology has been concerned in recent years which can achieve better performance of human-computer interaction. Based on the study of the touch screen human-computer interaction principle, a multiple touch screen based on infrared optical technique has been designed and developed, and the design of the program has been verified.The hardware design of infrared touch screen with the system architecture of MCU and FPGA can achieve a better performance. MCU is responsible for data processing tasks and information exchange with the host computer, while FPGA taking charge of the logic scanning task of infrared transmitter module and receiver module. With the help of their respective performance advantages, the system is to achieve faster scanning speed that is needed to compute the coordinate information of the multi-touch points. Infrared touch screen software system has been developed based on the embedded real-time kernelμCOS-Ⅱ. The program mainly contains the task of digital data collection for the analog signal of infrared receiver, the task of coordinate information of computing and the USB data communication. The system software would have a better management of system resources with the help of real-time kernelμCOS-Ⅱ, which will establish a stability and reliability system.Infrared touch screen with USB bus as a communication interface with the host computer is powered through the USB bus power system, which is plug and play device. Based on the research of infrared LED luminescence properties, we propose the infrared light multi-axis scanning programs to remove the ghost points appeared in infrared multiple points system, and the programs has a good applications in multiple touch scanning process. Based on real-time detection of ambient light, the LED current was adjusted to adapt the change of ambient light to improve the touch-screen anti-jamming capability. By calling Silicon Labs USB API functions and drawing functions from OpenCV library, the test program is provided to make functional verification for infrared touch screen system.The multiple touch screen can realize two points combination function with high response speed, and operate in indoor and outdoor environment with resolution ratio of 1024×768, which can meet the needs of the general display.