A viewing transform matrix indicating a position and a orientation of an
HMD is generated according to a signal indicating the position and the
orientation of the HMD. On the other hand, a landmark and its position are
detected based on a captured picture, and a correction matrix .DELTA.Mc is
generated based on the detected position of the landmark. The position and
orientation of the HMD is corrected by using a viewing transform matrix
and a correction matrix .DELTA.Mc generated in the above mentioned
processes, a picture of a virtual object is generated according to an
external parameter indicating the corrected position and the orientation
of the HMD, and a picture of augmented reality is generated. The generated
picture of the augmented reality is displayed on a display unit.
