Multi touch system is a system that uses a projector to project a large image and achieve multi touch on the projected image. Theoretically, it can achieve N-touch, as long as you have enough people, the accuracy can reach 10mm (1cm). Imported laser equipment and high-definition cameras are used for capture, making it precise and controllable. The system is stable to use, sensitive to operation, low in cost, and requires the development of a flash trigger program for touch control