POSITION DETECTING DEVICE, POSITION DETECTING METHOD, POSITION DETECTING PROGRAM, AND COMPOSITE REALITY PROVIDING SYSTEM

摘要

The position of an object in the real world in the screen can be detected with high accuracy by means of a constitution simpler than conventional. A special marker image (MKZ) so graded that the brightness level gradually varies along the X- and Y-axes and composed of areas is created. The special marker image (MKZ) is displayed at a position opposed to a robot (3) having a shape of an automobile on the screen of a liquid crystal display (2). The brightness level variations along the X- and Y-axes in the position detection areas (PD1A), PD2A, PD3, PD4 of the special marker image (MKZ) are detected by means of sensors (SR1 to SR4) installed on the robot (3). The variation of the relative position relation between the special marker image (MKZ) and the robot (3) is calculated from the brightness level variations, and thus the position on the screen of the liquid crystal display (2) is determined.