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Human body estimation is one of the active research fields in computer vision. It is widely used in human-computer interaction, pattern recognition, intelligent monitoring system and human behavior detection. A single depth camera has a limited range of observations thus can only estimate the human joint position which is in its field of view. To track human motion in a large area, a camera network...
In the Third-Generation Partnership Project (3GPP) Long-Term Evolution (LTE) specifications, several 2-D positioning methods have been proposed to support location-based services (LBSs). It has been shown that the observed time difference of arrival (OTDOA) method provides the best result. With the advent of the fifth-generation cellular systems, 3-D beamforming will be introduced, and 2-D positioning...
The absolute orientation problem arises often in vision and robotics. Despite that robust algorithmic solutions exist for quite some time, they all rely on matrix factorizations such as eigen or singular value decomposition. These factorizations are relatively expensive to compute, therefore might become a performance bottleneck when absolute orientation needs to be repeatedly computed on low-end...
Curve-skeletons encode both geometrical and topological information of 3D volumes (sets of voxels), and are key to many applications. However, due to the complexity and variability of the shapes, there is a variety of algorithms yielding skeletons suitable for certain objects, but inappropriate for others. In this article, we are interested in filtering skeletons of digital tubular objects with varying-diameter...
Hybrid source localization methods have proved to be able to improve the accuracy of position estimation. But several existing hybrid algorithms deal with two-dimensional (2D) scenarios only or require numerical search. This paper introduces a three-dimensional (3D) passive localization method using the active time of arrival (TOA) measurement and the one TOA and two angle of arrival (AOA) pairs observed...
Hydrodynamic cavitation is an effective and alternative treatment method in various biomedical applications such as kidney stone erosion, ablation of benign prostatic hyperplasia tissues and annihilation of detrimental cells. In order to effectively position the orifice of bubbly cavitating flow generator towards the target and control the destructive cavitation effect, cone angle of multi-phase bubbly...
Persons with walking frames are often limited with respect to visual acuity and they are depending on assistance. To give them the possibility to move free and autonomous in their environment an intelligent assistance system is proposed which can be mounted on a walking frame is used to observe the scene in walking direction, and obstacles have to be detected. Especially, stairways represent a high...
In indoor spaces, plane features are general geometric primitives that are robust to noise. To estimate the relative displacement and orientation between two consecutive 3D poses, at least three-pair correspondences of planes with different normals are needed at both poses. Otherwise, the estimated state falls into degeneracy, which is usually caused by the narrow field-of-view (FoV) of sensors as...
A distributed coordinated dynamic sensor network for optimal environmental field estimation is proposed and tested on simulated and real data. The architecture is used to distribute the estimation of 3D time-varying fields on a network of underwater gliders in which communication constraints are one of the main limiting factors for achieving complete network automation and de-centralization. The dynamic...
This paper presents Sparse Depth Odometry (SDO) to incrementally estimate the 3D pose of a depth camera in indoor environments. SDO relies on 3D keypoints extracted on dense depth data and hence can be used to augment the RGB-D camera based visual odometry methods that fail in places where there is no proper illumination. In SDO, our main contribution is the design of the keypoint detection module,...
This paper investigates the problem of how to improve angle-of-arrival (AOA) target localization accuracy by finding an optimal AOA sensor deployment strategy in 3D space. Under the assumption of constant absolute elevation angles for the sensors, a novel and simple optimal sensor deployment criterion is proposed based on minimizing the trace of inverse Fisher information matrix. Our analysis shows...
An algorithm for selecting nearest neighbors at a variable scale rather than a fixed search radius in point cloud neighbor search is proposed in this paper. We employ the concepts in differential geometry and divide the point cloud into different clusters according to their surface types. Not only the distance metric but also the clusters' surface type is taken into condition when we search the neighbors...
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