Interactive projection system and interactive method

The invention relates to an interactive projection system, comprising a control device, a projection device, an acquisition device and an interactive pen; firstly, the control device controls the projection device to lead a calibrated picture to be projected to a projection area, and then acquisition is carried out by the acquisition device, and the control device works out the projection transformation matrix according to the collected calibrated image and the original calibrated picture in the control device, so as to realize simple and rapid calibration of the system; when interactive operation is carried out, LED is triggered and gives out infrared light when the LED interactive pen is contacted with a screen, and capture is carried out by the image acquisition device in a real time manner; in addition, the software is tested by the developed interactive pen to realize location of the LED interactive pen; according to the obtained projection transformation matrix by calibration, the position information of the projection transformation matrix is transformed into mouse position information in the control device and is projected out by the projection device, thereby realizing interactive operation on the projection screen.