Camera motion estimation through planar deformation determination

In this paper, we propose a global method for estimating the motion of a camera which films a static scene. Our approach is direct, fast and robust, and deals with adjacent frames of a sequence. It is based on a quadratic approximation of the deformation between two images, in the case of a scene with constant depth in the camera coordinate system. This condition is very restrictive but we show that provided translation and depth inverse variations are small enough, the error on optical flow involved by the approximation of depths by a constant is small. In this context, we propose a new model of camera motion, that allows to separate the image deformation in a similarity and a ``purely'' projective application, due to change of optical axis direction. This model leads to a quadratic approximation of image deformation that we estimate with an M-estimator; we can immediatly deduce camera motion parameters.Comment: 21 pages, version modifi\'ee accept\'e le 20 mars 200

A location-based communication platform: integrating file sharing with interpersonal contact

Gemstone Team FLIP (File Lending in Proximity)Sharing on the Internet, even among computing devices in close proximity, is both inefficient and inconvenient. Online services and websites do not take advantage of easily obtainable geo-locational data that can improve sharing. We at Team FLIP have extended an existing mapping system called TerpNav with functionality that allows proximate users to interact and collaborate while sharing digital information. This study demonstrates both the feasibility of and demand for a more efficient and interactive method to exchange information among proximate networks of people

An Optical Tracking System for VRAR-Applications

In this paper, an optical tracking system is introduced for the use within Virtual and Augmented Reality applications. The system uses retroreffective markers which are attached to a special designed interaction device. The construction of the device allows us to gather six degrees of freedom. In order to achieve high tracking precision we introduce a calibration algorithm which results in sub-pixel accuracy and is therefore well applicable within Augmented Reality scenarios. Further the algorithm for calculating the pose of a rigid body is described. Finally, the optical tracking system is evaluated in regard to its accuracy

Highly accurate DSM reconstruction using Ku-band airborne InSAR

We present a newly developed airborne InSAR system incorporating a novel phase unwrapping algorithm, capable of retrieving a highly accurate Digital Surface Model (DSM). The SAR sensor system, with a spatial resolution of 30 cm, is carried on an airborne platform which has two antennas placed at a baseline length of 1 meter. We have established a DSM reconstruction processing technique, which includes the new ”Iterated Conditional Modes-Minimum Cost Flow ” (ICM-MCF) phase-unwrapping algorithm. The ICM-MCF algorithm finds a locally optimal configuration of unwrapped phases under a well-characterized statistical model of the terrain and noise. An experimental field observation was carried out in Tsukuba, Japan. The DSM was generated, and the height accuracy of the SAR-DSM was evaluated by comparing with laser profile