Abstract. In this paper, we describe a novel camera calibration method to estimate the extrinsic parameters and the focal length of a camera by using only one single image of two coplanar circles with arbitrary radius.We consider that a method of simple operation to estimate the extrinsic parameters and the focal length of a camera is very important because in many vision based applications, the position, the pose and the zooming factor of a camera is adjusted frequently.An easy to use and convenient camera calibration method should have two characteristics: 1) the calibration object can be produced or prepared easily, and 2) the operation of a calibration job is simple and easy. Our new method satisfies this requirement, while most existing camera calibration methods do not because they need a specially designed calibration object, and require multi-view images. Because drawing beautiful circles with arbitrary radius is so easy that one can even draw it on the ground with only a rope and a stick, the calibration object used by our method can be prepared very easily. On the other hand, our method need only one image, and it allows that the centers of the circle and/or part of the circles to be occluded.Another useful feature of our method is that it can estimate the focal length as well as the extrinsic parameters of a camera simultaneously. This is because zoom lenses are used so widely, and the zooming factor is adjusted as frequently as the camera setting, the estimation of the focal length is almost a must whenever the camera setting is changed. The extensive experiments over simulated images and real images demonstrate the robustness and the effectiveness of our method.
Abstract-3D video is a real 3D movie recording the object's full 3D shape, motion, and precise surface texture. This paper first proposes a parallel pipeline processing method for reconstructing dynamic 3D object shape from multi-view video images, by which a temporal series of full 3D voxel representations of the object behavior can be obtained in real-time. To realize the real-time processing, we first introduce a plane-based volume intersection algorithm: represent an observable 3D space by a group of parallel plane slices, back-project observed multi-view object silhouettes onto each slice, and apply 2D silhouette intersection on each slice. Then, we propose a method to parallelize this algorithm using a PC cluster, where we employ 5 stage pipeline processing in each PC as well as slice-by-slice parallel silhouette intersection. Several results of the quantitative performance evaluation are given to demonstrate the effectiveness of the proposed methods. In the latter half of the paper, we present an algorithm of generating video texture on the reconstructed dynamic 3D object surface. We first describe a naive viewindependent rendering method and show its problems. Then, we improve the method by introducing image-based rendering techniques. Experimental results demonstrate the effectiveness of the improved method in generating high fidelity object images from arbitrary viewpoints.
Robust manipulation strategies of deformable ob jects will be presented. Manipulation of deformable objects can be found in manyficlds su ch as garment ind1L8try and food industry. Guidance of m1J ,ltiple points on a deformable object is a pr imitive oper ation in the manipulation of deformable objects. In this guidance, the points often cannot be manipulated dil"cct/y. A model of the manipulated deformable ob ject is needed in order to perform these operations.It is, however, difficu,/t to build a precise model of a deformable object. Thus, we need a robust con trol scheme that allows us to realize the operations su ccessfully despite of discrepancy between a manip-1Llated deformable object and its model.In this paper', we will firstly de1'ive a mathernat ' ical model 0/ deformable objects for their' manipula tion. Second, indirect simultaneous positioning op f>.llll'iOTlS of dejorrna.ble objects (LTC for·mulated. Then, we will Pro1JOse a PlD feedl)(lck contml law with the 7"011.911. object model to realize the manipulation. Fnr theTmOl'e, 711 1'. will pmpose a .� irnple PID feedback con tTol law without de/onnation model. The validity and the 7"OImstnC.�8 of the proposed manipnlation method will be 811.011111. throngh simulation re.!1J.lts.
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