Three-Dimensional Measurement System Using a Cylindrical Mirror Yuuki Uranishi, Mika Naganawa, Yoshihiro Yasumuro, Masataka Imura, Yoshitsugu Manabe, and Kunihiro Chihara Graduate School of Information Science, Nara Institute of Science and Technology, 8916-5 Takayama Ikoma, Nara, Japan {yuuki-u, naganawa, yasumuro, imura, manabe, chihara}@is.naist.jp http://chihara.naist.jp/ Abstract. We propose a novel method for measuring a whole three- dimensional shape of an object with a simple structured system. The proposed system consists of a single CCD camera and a cylindrical mir- ror. A target object is placed inside the cylindrical mirror and an image is captured by the camera from above. There are two or more points that have the same origin in the captured image: one is observed directly, and the other is observed via the mirror. This situation means that a point is observed by a real camera and virtual cameras at the same time. Therefore, the three-dimensional shape of the object can be obtained using stereo vision. We simulated an actual experimental situation and measured the three-dimensional shape of the object from the simulated image, and the results have demonstrated that the proposed method is useful for measuring the whole three-dimensional shape. 1 Introduction Whole three-dimensional shape measuring and model reconstructing have a wide area of applications, including virtual museums [1] and digital archiving of relics [2]. Most of whole three-dimensional models are built from multiple range images. Registration and integration of the images are cumbersome procedures. There- fore, it is highly desirable that a whole shape of the object is easily measured in a single shot. The three-dimensional measurement methods are classified into two groups: one is an active measurement method, and the other is a passive measurement method. The active measurement method, such as Time-of-Flight [3] and Structured Lighting [4], obtains a shape of the target object by projecting a light or some kind of energy and by measuring its reflection. This method provides a precise shape of the object as a dense point cloud. However, it is impossible to obtain the whole shape data at once due to the limitation of the viewpoint. There- fore, in order to reconstruct the whole shape data, measurement from multiple viewpoints is required by moving a turntable or the sensor itself. There are several existing methods for passive measurement. For example, Visual Hull [5][6] constructs approximation of a whole object shape from silhou- H. Kalviainen et al. (Eds.): SCIA 2005, LNCS 3540, pp. 399–408, 2005. c  Springer-Verlag Berlin Heidelberg 2005