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The lack of depth information in camera images has triggered much work on their use for localization and mapping in robotics. In particular, specific landmark parametrizations that isolate the unknown depth in one variable, and that allows to handle the associated large uncertainties have been proposed. Recently, an innovative parametrization (Parallax Angle) has shown to outperform the others in...
This paper introduces a new methodology for environment characterization. This methodology is based on analysis of the eigenvalues of Laplace-Beltrami operator over 3 dimensional point clouds. Recognizing revisited places can be facilitated by characterizing the environment through a descriptor. The idea of analyzing point clouds using the eigenvalues of Laplace-Beltrami operator for characterization...
In this paper, a new distributed algorithm is presented to achieve the consensus of time variations and that of initial time simultaneously. By combining both controller and estimator design methods, it obtains higher synchronization precision with stronger robustness against noisy inputs resulted from crystal oscillators. Furthermore, the control input is ensured bounded to make our algorithm realizable...
In this work, we present an appearance based human activity recognition system. It uses background modeling to segment the foreground object and extracts useful discriminative features for representing activities performed by humans and robots. Subspace based method like principal component analysis is used to extract low dimensional features from large voluminous activity images. These low dimensional...
This paper presents a novel approach to background subtraction which aims to extract moving objects in video stream. To this end, a novel background model is proposed by using both working backgrounds and candidate backgrounds, which can be transferred to each other according to an adaptive mechanism. The input image (video frame) is compared and evaluated with these dual-class backgrounds (DCB) to...
We present a novel pipeline for augmenting a 3D eye-glass mesh into a person's face. While doing so, we take care about the proper fitment of the glass in terms of pupilary distance computed automatically, which is user-friendly in compare to standard marker based approaches. Our method also performs rigid eye-glass temple correction during augmentation followed by tracking to present realistic rendering...
In this paper, we propose a dense approach for 3D rotation estimation between spherical images, which is simultaneously able to recover the large rotations, robust under clutter and small translations. The key idea is to represent the spherical images by 3D shapes of the triangular mesh surfaces based on image intensity signal. This allows to apply the spherical harmonics representation as 3D shape...
In this paper, it is shown that the Enhanced Unified Camera Model, which is used to model fisheye cameras, projects straight lines into conic sections. Then a way to find equations of straight line projections is proposed. The method is applied to epipolar curves to adapt the Semi-Global Matching algorithm to fisheye stereo systems to compute a dense direct stereo correspondence without undistortion...
This paper studies the problem of using an autonomous underwater vehicle (AUV) to seek the source of some signal in the underwater environment. To avoid the redundant travels for getting the local gradient in existing methods, we propose a novel source-seeking strategy in which the AUV keeps updating an estimated field model using measurements along its gradient-climbing path. Based on the convergence...
Atomic Force Microscopy (AFM) captures Nano-scale resolution biopolymers with relative ease, and has been used to image many string-like biopolymer samples such as DNA. This research proposes a standard method to calculate the persistence length(s) of DNA samples, imaged by AFM. Both simulated DNA through Worm-Like Chain (WLC) modeling and DNA images scanned from actual AFM systems are used to demonstrate...
A snake-like robot is a hyper-redundant robot. It has flexible movement ability and high stability with low center of gravity. It is very suitable for environment detection in the rugged road or narrow space. In this paper, a 16-DOFs snake robot is composed. It has ten 2-DOFs modular spherical-shape joints. The joints are arranged as the structure of "(Roll-Pitch)-(Roll-Pitch)-", where "(Roll-Pitch)"...
The paper addresses the operational reliability and safety of automated guided vehicles along roadways. These operations most often require very tight integration of environmental sensing and vehicle dynamics control. This contribution relies on determining the relevant lane boundaries using conventional camera sensor and proposes a constrained longitudinal and lateral control strategy for fully automated...
It is becoming increasingly achievable for steel bridge structures, which are normally both inaccessible and hazardous for humans, to be inspected and maintained by autonomous robots. Steel bridges have been traditionally constructed by securing plate members together with rivets. However, rivets present a challenge for robots both in terms of cleaning and surface traversal. This paper presents a...
Although adaptive control offers a unique way to control dynamical systems without excessive reliance on their mathematical models, it is well known that nonidentical command profiles result in nonidentical closed-loop responses with such controllers, and therefore, it is of practical interest to study theoretical ways to construct predictable closed-loop responses when adaptive controllers are in...
This paper studies the distributed containment control problem of multiple rigid bodies with event-triggered controllers. An event-triggered cooperative strategy is proposed based on combinational measurements. In this framework, each agent is triggered only at its own triggering instants, which reduces the frequency of controller updates in practice. It is shown that the triggering time sequence...
In this paper, leader-following consensus of the discrete-time heterogenous multi-agent system with bounded communication delays is studied. The heterogeneous multi-agent system is composed of first-order and second-order integrator agents. By applying the graph theory and the algebra theory, sufficient consensus criteria are obtained to guarantee that each agent can track the leader. Despite there...
A key problem in event-triggered control of multi-agent systems is to design triggering conditions. We first give an overview of existing triggering conditions used in the literature. However, not all existing triggering conditions can both relax continuous communication between neighboring agents and admit a positive lower bound of inter-event times. Then, we propose two new triggering conditions...
Macroscopic fundamental diagram (MFD) that describes traffic flow in an urban road network can be used to design perimeter control method to regulate the traffic flow from a macroscopic level. Most of the perimeter control algorithms are regarded as a kind of model-based feedback control method, whose performance is hardly to improve in practice due to the model uncertainty. By noticing the repetitive...
In this study, a variable viscoelastic joint system with a clutch for a human assistance was proposed. The variable viscoelastic joint system comprised antagonized artificial muscles and magneto-rheological fluid brake (MR-brake). This system enabled the human assisting device such as exoskeletons to retain structural softness when compared with the existing devices driven by motor and reduction gear,...
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