The invention provides an auxiliary positioning method of computer projection and the interactive demonstration
system. The method is as follows. It is assumed that there is n anchor points (x1 ', y1 '), (x2 ', y2'),... (xn ', yn ') on the computer screen, corresponding to n projection points (x1, y1) and (x2, y2),... (xn, yn) on interactive
projection screen. Once The n projection points are hit, and their coordinates information (x1, y1), (x2, y2),... (xn, yn) are transmitted to the computer. According to these information, all the parameters of the function p (x', y') = F (P (x, y)) are calculated, and then any operation points P (x, y) on interactive
projection screen can be transformed into the anchor points p (x ', y ') on the computer screen. The
system consists of interconnected computers, projectors and interactive
projection screen. If the method is used for positioning projection coordinates, it would make beneficial effect to the
distortion correction such as trapezoidal, pillow and nonlinear
projection display images, and accurate information alternation between the interactive demonstration screen and the computer.