In the walk-through via an Internet, we move a mouse to imitate a walk by our foot [3]. Here, we consider the case which maps a real motion to an immersive virtual reality environment. For example, we wander in computer room as if we do in a museum for watching some arts. The user?s head motion at a relative large scale environment is needed to be known for realizing this-kind-like immersive virtual reality.

This research proposes a method of estimating the head motion based upon vision approaches for mapping a head motion to an immersive virtual reality environment. We put fiducial markers around the room to be changed virtually and use an omnidirectional image sensor to observe these markers. By mounting the visual sensor on a helmet, the head motion of a user who wears the helmet can be estimated by processing images captured from the omnidirectional image sensor. Since it has a 360 degree view, it can cope with a big head rotation motion compared with a normal camera. Since a head motion at every time is directly estimated from the observed markers, there is no accumulated errors in our method compared with a inertial sensor.