The method of measuring position/orientation in the real world determines the construction of the VR interface. This paper proposes a method of measuring marker position/orientation by image processing. The marker is rectangular. The position/orientation is measured using a single camera. The orientation of the marker is estimated by optimization, utilizing the information of two vanishing points obtained from an image. Then, the position of the marker is determined by calculations. This is facilitated because we have only to attach a marker to a target of measurements.
The expansion in the measurement of multiple objects is straightforward and the system can be constructed cheaply because no special circuitry is required. Also, the measurement range is easily modified by resetting the camera lens. The advantage of this method is shown by computer simulations and experimental results using a real image. The real-time measuring accuracy of the system, which was composed of ready-made devices and a highly distorted camera, was 0.5 degrees in directional deviations and 1 mm in depth deviation. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 3, 80(3): 1–12, 1997