RT info:eu-repo/semantics/article T1 Non-linearity analysis of depth and angular indexes for optimal stereo SLAM A1 Bergasa Pascual, Luis Miguel A1 Fernández Alcantarilla, Pablo A1 Schleicher Gómez, David K1 Extended Kalman filter K1 Localization K1 Mapping K1 Inverse depth parametrization K1 Non-linearity analysis K1 2D warping K1 Electrónica K1 Electronics AB In this article, we present a real-time 6DoF egomotion estimation system for indoor environments using a wide-angle stereo camera as the only sensor. The stereo camera is carried in hand by a person walking at normal walking speeds 3–5 km/h. We present the basis for a vision-based system that would assist the navigation of the visually impaired by either providing information about their current position and orientation or guiding them to their destination through different sensing modalities. Our sensor combines two different types of feature parametrization: inverse depth and 3D in order to provide orientation and depth information at the same time. Natural landmarks are extracted from the image and are stored as 3D or inverse depth points, depending on a depth threshold. This depth threshold is used for switching between both parametrizations and it is computed by means of a non-linearity analysis of the stereo sensor. Main steps of our system approach are presented as well as an analysis about the optimal way to calculate the depth threshold. At the moment each landmark is initialized, the normal of the patch surface is computed using the information of the stereo pair. In order to improve long-term tracking, a patch warping is done considering the normal vector information. Some experimental results under indoor environments and conclusions are presented. PB MDPI SN 1424-8220 YR 2010 FD 2010-04-26 LK http://hdl.handle.net/10017/43550 UL http://hdl.handle.net/10017/43550 LA eng NO Ministerio de Ciencia e Innovación DS MINDS@UW RD 25-abr-2024