Head mounted display and control method therefor

Abstract

A viewpoint information calculation unit ( 710 ) calculates a difference value (α) between reference position and orientation information and position and orientation information held by a camera viewpoint storage unit ( 207 ), and a difference value (β) between the reference position and orientation information and position and orientation information held by a CG viewpoint storage unit ( 208 ). If |α|≧|β|, a physical space image is shifted by a shift amount calculated in accordance with the resolution of a display unit ( 213 ), a difference amount, and the angle of view of a camera ( 203 ), and is composited with a virtual space image. If |α|<|β|, the virtual space image is shifted by the shift amount, and is composited with the physical space image.

1 . A head mounted display including an image sensing device, a display device, and a position and orientation sensor, comprising:
 an acquisition unit adapted to acquire, every time receiving a physical space image sensed by the image sensing device, position and orientation information representing a position and orientation which has been measured by the position and orientation sensor at the time of sensing the received physical space image, and record the position and orientation information together with the received physical space image in a first memory;   a transmission unit adapted to transmit the position and orientation information acquired by the acquisition unit to an external computer;   a reception unit adapted to receive, from the computer, the position and orientation information transmitted by the transmission unit and a virtual space image generated by the computer on the basis of the position and orientation information, and record the received position and orientation information and the received virtual space image in a second memory;   a calculation unit adapted to calculate a difference amount of an orientation component between the position and orientation information held in the first memory at a display timing of the display device and the position and orientation information held in the second memory at the display timing;   a unit adapted to calculate a first difference value between the position and orientation information acquired by the acquisition unit at around the display timing of the display device and the position and orientation information held in the first memory;   a unit adapted to calculate a second difference value between the position and orientation information acquired by the acquisition unit at around the display timing of the display device and the position and orientation information held in the second memory; and   a composition unit adapted to composite the physical space image held in the first memory at the display timing of the display device and the virtual space image held in the second memory at the display timing of the display device, and   wherein the composition unit selects, based on a magnitude relationship between the first difference value and the second difference value, either a composition process of shifting a virtual space image to be composited by a shift amount calculated in accordance with resolution information representing a resolution of the display device, the difference amount, and angle-of-view information representing an angle of view of the image sensing device and compositing the shifted virtual space image, or a composition process of shifting a physical space image to be composited by a shift amount calculated in accordance with the resolution information representing the resolution of the display device, the difference amount, and the angle-of-view information representing the angle of view of the image sensing device and compositing the shifted physical space image, and the composition unit executes the selected composition process.