| 摘要 |
<p>A display device has a screen that can be positioned in arbitrary postures including a reference posture relative to a space having a reference horizontal orientation. The screen has an xyz orthogonal coordinate system, and the posture of the screen in the space is defined by z-x-z Euler angles ±, ², and ³ of the xyz orthogonal coordinate system. The screen displays an image to enable recognition of the reference horizontal orientation of the space. A control device derives a specific parameter ±+³ as an angle by which the image is rotated so that the reference horizontal orientation recognized from the image follows the reference horizontal orientation of the space when the image is displayed on the screen at arbitrary postures.</p> |
