Enhancing smart environments with mobile robots

Sensor networks are becoming popular nowadays in the development of smart environments. Heavily relying on static sensor and actuators, though, such environments usually lacks of versatility regarding the provided services and interaction capabilities. Here we present a framework for smart environments where a service robot is included within the sensor network acting as a mobile sensor and/or actuator. Our framework integrates on-the-shelf technologies to ensure its adaptability to a variety of sensor technologies and robotic software. Two pilot cases are presented as evaluation of our proposal.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Accurate Stereo Visual Odometry with Gamma Distributions

Point-based stereo visual odometry systems typically estimate the camera motion by minimizing a cost function of the projection residuals between consecutive frames. Under some mild assumptions, such minimization is equivalent to maximizing the probability of the measured residuals given a certain pose change, for which a suitable model of the error distribution (sensor model) becomes of capital importance in order to obtain accurate results. This paper proposes a robust probabilistic model for projection errors, based on real world data. For that, we argue that projection distances follow Gamma distributions, and hence, the introduction of these models in a probabilistic formulation of the motion estimation process increases both precision and accuracy. Our approach has been validated through a series of experiments with both synthetic and real data, revealing an improvement in accuracy while not increasing the computational burden.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Project "PROMOVE: Advances in mobile robotics for promoting independent life of elders", funded by the Spanish Government and the "European Regional Development Fund ERDF" under contract DPI2014-55826-R

Improvement of the sensory and autonomous capability of robots through olfaction: the IRO Project

Proyecto de Excelencia Junta de Andalucía TEP2012-530Olfaction is a valuable source of information about the environment that has not been su ciently exploited in mobile robotics yet. Certainly, odor information can contribute to other sensing modalities, e.g. vision, to successfully accomplish high-level robot activities, such as task planning or execution in human environments. This paper describes the developments carried out in the scope of the IRO project, which aims at making progress in this direction by investigating mechanisms that exploit odor information (usually coming in the form of the type of volatile and its concentration) in problems like object recognition and scene-activity understanding. A distinctive aspect of this research is the special attention paid to the role of semantics within the robot perception and decisionmaking processes. The results of the IRO project have improved the robot capabilities in terms of efciency, autonomy and usefulness.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Analyzing interference between RGB-D cameras for human motion tracking

Multi-camera RGB-D systems are becoming popular as sensor setups in Computer Vision applications but they are prone to cause interference between them, compromising their accuracy. This paper extends previous works on the analysis of the noise introduced by interference with new and more realistic camera configurations and different brands of devices. As expected, the detected noise increases as distance and angle grows, becoming worse when interference is present. Finally, we evaluate the effectiveness of the proposed solutions of using DC vibration motors to mitigate them. The results of this study are being used to assess the effect of interference when applying these setups to human motion tracking.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Plan Propio de Investigación de la UMA. Junta de Andalucía, proyecto TEP2012-53

An Analytical Solution to the IMU Initialization Problem for Visual-Inertial Systems

The fusion of visual and inertial measurements is becoming more and more popular in the robotics community since both sources of information complement well each other. However, in order to perform this fusion, the biases of the Inertial Measurement Unit (IMU) as well as the direction of gravity must be initialized first. Additionally, in case of a monocular camera, the metric scale is also needed. The most popular visual-inertial initialization approaches rely on accurate vision-only motion estimates to build a non-linear optimization problem that solves for these parameters in an iterative way. In this paper, we rely on the previous work in [1] and propose an analytical solution to estimate the accelerometer bias, the direction of gravity and the scale factor in a maximum-likelihood framework. This formulation results in a very efficient estimation approach and, due to the non-iterative nature of the solution, avoids the intrinsic issues of previous iterative solutions. We present an extensive validation of the proposed IMU initialization approach and a performance comparison against the state-of-the-art approach described in [2] with real data from the publicly available EuRoC dataset, achieving comparable accuracy at a fraction of its computational cost and without requiring an initial guess for the scale factor. We also provide a C++ open source reference implementation

Experimental Analysis of Appearance Maps as Descriptor Manifolds Approximations

Images of a given environment, coded by a holistic image descriptor, produce a manifold that is articulated by the camera pose in such environment. The correct articulation of such Descriptor Manifold (DM) by the camera poses is the cornerstone for precise Appearance-based Localization (AbL), which implies knowing the correspondent descriptor for any given pose of the camera in the environment. Since such correspondences are only given at sample pairs of the DM (the appearance map), some kind of regression must be applied to predict descriptor values at unmapped locations. This is relevant for AbL because this regression process can be exploited as an observation model for the localization task. This paper analyses the influence of a number of parameters involved in the approximation of the DM from the appearance map, including the sampling density, the method employed to regress values at unvisited poses, and the impact of the image content on the DM structure. We present experimental evaluations of diverse setups and propose an image metric based on the image derivatives, which allows us to build appearance maps in the form of grids of variable density. A preliminary use case is presented as an initial step for future research

Pulmonary arterial dysfunction in insulin resistant obese Zucker rats

<p>Abstract</p> <p>Background</p> <p>Insulin resistance and obesity are strongly associated with systemic cardiovascular diseases. Recent reports have also suggested a link between insulin resistance with pulmonary arterial hypertension. The aim of this study was to analyze pulmonary vascular function in the insulin resistant obese Zucker rat.</p> <p>Methods</p> <p>Large and small pulmonary arteries from obese Zucker rat and their lean counterparts were mounted for isometric tension recording. mRNA and protein expression was measured by RT-PCR or Western blot, respectively. K_Vcurrents were recorded in isolated pulmonary artery smooth muscle cells using the patch clamp technique.</p> <p>Results</p> <p>Right ventricular wall thickness was similar in obese and lean Zucker rats. Lung BMPR2, K_V1.5 and 5-HT_2Areceptor mRNA and protein expression and K_Vcurrent density were also similar in the two rat strains. In conductance and resistance pulmonary arteries, the similar relaxant responses to acetylcholine and nitroprusside and unchanged lung eNOS expression revealed a preserved endothelial function. However, in resistance (but not in conductance) pulmonary arteries from obese rats a reduced response to several vasoconstrictor agents (hypoxia, phenylephrine and 5-HT) was observed. The hyporesponsiveness to vasoconstrictors was reversed by L-NAME and prevented by the iNOS inhibitor 1400W.</p> <p>Conclusions</p> <p>In contrast to rat models of type 1 diabetes or other mice models of insulin resistance, the obese Zucker rats did not show any of the characteristic features of pulmonary hypertension but rather a reduced vasoconstrictor response which could be prevented by inhibition of iNOS.</p

Thromboxane A2-Induced Inhibition of Voltage-Gated K+ Channels and Pulmonary Vasoconstriction

8 pages, 6 figures.Voltage-gated K+ channels (KV) and thromboxane A2 (TXA2) play critical roles in controlling pulmonary arterial tone under physiological and pathological conditions. We hypothesized that TXA2 might inhibit KV channels, thereby establishing a link between these two major pathogenic pathways in pulmonary hypertension. The TXA2 analogue U46619 inhibited IK(V) (Emax=56.1±3.9%, EC50=0.054±0.019 µmol/L) and depolarized pulmonary artery smooth muscle cells via activation of TP receptors. In isolated pulmonary arteries, U46619 simultaneously increased intracellular Ca2+ concentration and contractile force, and these effects were inhibited by nifedipine or KCl (60 mmol/L). U46619-induced contractions were not altered by the inhibitors of tyrosine kinase genistein or Rho kinase Y-27632 but were prevented by the nonselective protein kinase C (PKC) inhibitors staurosporine and calphostin C. Furthermore, these responses were sensitive to Gö-6983 but insensitive to bisindolylmaleimide I and Gö-6976. Based on the specificity of these drugs, we suggested a role for an atypical PKC in U46619-induced effects. Thus, treatment with a PKC{zeta} pseudosubstrate inhibitor markedly prevented the vasoconstriction, the inhibition of IK(V), and the depolarization induced by U46619. Western blots showed a transient translocation of PKC{zeta} from the cytosolic to the particulate fraction on stimulation with U46619. These results indicate that TXA2 inhibits IK(V), leading to depolarization, activation of L-type Ca2+ channels, and vasoconstriction of rat pulmonary arteries. We propose PKC{zeta} as a link between TP receptor activation and KV channel inhibition.This work was supported by grants from the Comisión Interministerial de Ciencia y Tecnología (SAF 2002/02304) and Comunidad Autónoma de Madrid (08.4/0036.2001 and 08.3/0008/2001). A.C. and L.M. are supported by grants from Red Temática de Investigación Cardiovascular and Ministerio de Educación Cultura y Deporte, respectively.Peer reviewe