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Sensors Journal, IEEE

Early Access Articles

Early Access articles are new content made available in advance of the final electronic or print versions and result from IEEE's Preprint or Rapid Post processes. Preprint articles are peer-reviewed but not fully edited. Rapid Post articles are peer-reviewed and edited but not paginated. Both these types of Early Access articles are fully citable from the moment they appear in IEEE Xplore.

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Displaying Results 1 - 25 of 168
  • Design and Calibration of the Unilateral Sensitive Soil Moisture Sensor

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1056 KB)  

    Reliable and affordable moisture sensors with a simplified calibration process for obtaining the water content information of soil/soilless substrates were limited. In this paper, an unilateral sensitive capacitive soil moisture sensor, based on the improved ECH2O sensor probe structure, was presented. Through simulating the relationship between the ratio of plate space and plate width (a/b) and probe sensitivity, sensitive depth respectively, the size of the sensor was determined with ANSYS firstly. Capacitance measurement circuit based on resonant principle was then designed. The relationship between the output of the sensor and the soil water content calibration model (β parameter model), was investigated. As a result, we proposed a two-step calibration β method. Experimental results showed that β parameter model appropriately described the relationship between the output and the soil water content, the minimum correlation coefficient R2=0.9554 in the soil, peat, perlite, vinegar residue. The measurement error of β parameter model was less than 0.025 units except in perlite. The error caused by the change of bulk density was less than 0.025 units in peat and vinegar residue. Therefore, the two-step calibration β method is suitable for calibrating the sensor. View full abstract»

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  • Mobile Sink based Adaptive Immune Energy-Efficient Clustering Protocol for Improving the Lifetime and Stability Period of Wireless Sensor Networks

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4008 KB)  

    Energy hole problem is a critical issue for data gathering in Wireless Sensor Networks. Sensors near the static sink act as relays for far sensor and thus will deplete their energy very quickly, resulting energy holes in the sensor field. Exploiting the mobility of a sink has been widely accepted as an efficient way to alleviate this problem. However, determining an optimal moving trajectory for a mobile sink is an NP-hard problem. Thus, this paper proposed a Mobile Sink based adaptive Immune Energy-Efficient clustering Protocol (MSIEEP) to alleviate the energy holes. MSIEEP uses the Adaptive Immune Algorithm (AIA) to guide the mobile sink based on minimizing the total dissipated energy in communication and overhead control packets. Moreover, AIA is used to find the optimum number of Cluster Heads (CHs) to improve the lifetime and stability period of the network. The performance of MSIEEP is compared with the previously published protocols; namely LEACH, LEACHGA, A-LEACH, rendezvous and MIEEPB using Matlab. Simulation results show that MSIEEP is more reliable and energy efficient as compared to other protocols. Furthermore, it improves the lifetime, the stability and the instability periods over the previous protocols, because it always selects CHs from highenergy nodes. Moreover, the mobile sink increases the ability of the proposed protocol to deliver packets to the destination. View full abstract»

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  • Electromagnetic Positioning for Tip Tracking and Shape Sensing of Flexible Robots

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2649 KB)  

    Wire-driven flexible robots are efficient devices for minimally invasive surgery, since they can work well in complex and confined environments. However, the real-time positional and shape information of the robot cannot be well estimated, especially when there is an unknown payload or force working on the end effector. In this paper, we propose a novel tip tracking and shape sensing method for wire-driven flexible robots. The proposed method is based on the length of each section of the robot as well as the positional and directional information of the distal end of each section of the robot. For each section, an electromagnetic sensor will be mounted at the distal end to estimate the positional and directional information. A reconstruction algorithm, which is based on a three order B´ezier Curve, is carried out utilizing the positional and directional information along with the length information of the section. This method provides the advantage of good tracking results and high shape reconstruction accuracy with limited modification to the robot. Compared with other reconstruction methods, no kinematic model is needed for reconstruction. Therefore, this method works well with an unknown payload that applied at the tip of the robot. The feasibility of the proposed method is verified by simulation and experimental results. View full abstract»

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  • Limits of BOTDA Range Extension Techniques

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1260 KB)  

    Brillouin-based temperature and strain sensors have attracted great attention of both the academic and industrial sectors in the past few decades due to their ability to perform distributed measurements. Particularly, Brillouin Optical Time Domain Analysis (BOTDA) systems have been applied in many different scenarios, proving particularly useful in those requiring especially wide coverage ranging extremely long distances, such as in civil structure monitoring, energy transportation or environmental applications. The extension of the measuring range in these sensors has therefore become one of the main areas of research and development around BOTDA. To do so, it is necessary to increase the Signal to Noise Ratio (SNR) of the retrieved signal. So far, several techniques have been applied in order to achieve this goal, such as pre-amplification before detection, pulse coding or Raman amplification. Here, we analyze these techniques in terms of their performance limits and provide guidelines that can assist in finding out which is the best configuration to break current range limitations. Our analysis is based on physical arguments as well as current literature results. View full abstract»

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  • A High Reliability Wearable Device for Elderly Fall Detection

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3230 KB)  

    Falls are critical events among elderly people that requires timely rescue. In this paper we propose a fall detection system consisting of an inertial unit that includes triaxial accelerometer, gyroscope and magnetometer with efficient data fusion and fall detection algorithms. Starting from the raw data, the implemented orientation filter provides the correct orientation of the subject in terms of Yaw, Pitch and Roll angles. The system is tested according to experimental protocols, engaging volunteers who performed simulated falls, simulated falls with recovery and Activities of Daily Living (ADL). By placing our wearable sensor on the waist of the subject, the unit is able to achieve fall detection performance above those of similar systems proposed in literature. The results obtained through commonly adopted protocols show excellent accuracy, sensitivity and specificity, improving the results of other techniques proposed in the literature. View full abstract»

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  • A Voltammetric Sensor Based on Multi-walled Carbon Nanotubes and a New Azoferrocene Derivative for Determination of Glutathione

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    A new azoferrocene derivative, N-4,4'-azodianiline(ferrocenyl Schiff base) (ADAF, [Fe(cp)(azcp)]), was synthesized by reaction of ferrocene carbaldehyde and 4,4'-azodianiline in n-hexane. Then, a novel multi-walled carbon nanotubes/ carbon-paste modified electrode (ADAFCNPE) using ADAF was fabricated for the electrocatalytic determination of glutathione (GSH) in hemolysed erythrocyte. The measurements were carried out by application of differential pulse voltammetry (DPV), cyclic voltammetry (CV), and chronoamperometry (CA). It was found that under the optimum conditions (pH = 6.0), the oxidation of GSH occurs at a potential about +0.52 V less positive than for the unmodified carbon-paste electrode. The electron-transfer coefficient (α) and rate constant for the chemical reaction between GSH and redox sites in the modified electrode were found to be 0.36 and 4.8 ×105 cm3 mol-1 s-1, respectively. The catalytic peak current was linearly dependent to the GSH concentration in the range of 0.3–3350 μM with a detection limit of 0.08 μM. The proposed method was applied for the highly sensitive determination of GSH in hemolysed erythrocyte using the standard addition method. View full abstract»

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  • An LCD-VCOM-Noise Resilient Mutual-Capacitive Touch-Sensor IC Chip with a Low-Voltage Driving Signal

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (926 KB)  

    A mutual-capacitive touch-sensor read-out Integrated circuit (ROIC) with a differential sensing scheme is proposed to reduce the driving pulse amplitude of touch sensor panel (TSP) down to 0.4 V. This reduction is achieved by mitigating the effect of the liquid crystal display (LCD) common-voltage (VCOM) noise which is time-periodic. To accomplish this mitigation, the TSP driving pulse (VSTM) is synchronized to the gate-driver-pulse generating signal (GCLK) of LCD, and its frequency is set to (2n+1) times the frequency of GCLK where n is a non-negative integer. The repetition period TN of the VCOM noise is one half of the GCLK period. A receiver channel consists of a charge amplifier, a chopper, and an integrator; all are in differential circuits. The chopper is driven by the VSTM. The integration period of the integrator is set to 2TN to suppress the periodic LCD noise. A referenceless clock and data recovery circuit is used to generate VSTM from GCLK continuously with time in spite of the discontinuity of GCLK during the VBLANK period. The proposed ROIC fabricated in a 0.35-???m CMOS was applied to a 6.9” 12x16 TSP located on a rather noisy 23” IPS-LCD monitor. The measured signal-to-noise ratio changes from 27 dB to 9 dB as the VSTM amplitude changes from 3.3 V to 0.4 V, where the GCLK frequency is 16.8 kHz and the VSTM frequency is 352.8 kHz. The reporting rate of the ROIC is 175 Hz. View full abstract»

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  • Information-Theoretic Measures on Intrinsic Mode Function for the Individual Identification Using EEG Sensors

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (884 KB)  

    In spite of recent advances, the interest in extracting knowledge hidden in the electroencephalogram(EEG) signals is rapidly growing, as well as their application in the computational neuro engineering field such as mobile robot control, wheelchair control and person identification using brainwaves. The large number of methods for EEG feature extraction demands a good feature for every task. Digging up the most unique feature would be worth for identification of individual using EEG signal. This research presents a novel approach for feature extraction of electroencephalogram (EEG) signal using the Empirical mode decomposition (EMD) and information-theoretic-method (ITM). The EMD technique is applied to decompose an EEG signal into set of intrinsic mode function (IMF). These decomposed signals are of the same length and in the same time domain as the Original Signal. Hence, EMD method preserves varying frequencies in time. To measure the performance of the features, we have used Hybrid learning for classification where we have selected Learning Vector Quantization Neural Network (LVQ-NN) with fuzzy algorithm. Furthermore, to investigate the performance and accuracy of each subject over the different cognitive tasks based on Cohen’s kappa coefficient. The results are compared with past methods in literature for feature extraction and classification methods. Results confirm that proposed features present a satisfactory performance. View full abstract»

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  • 3D Isosceles Triangular Ultrasonic Path of Transit-Time Ultrasonic Flowmeter: Theoretical Design & CFD Simulations

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2014 KB)  

    Increasing the coverage rate of ultrasonic path to flow field is helpful to improve measurement results’ accuracy of transit-time ultrasonic flowmeters (T-UFM) while asymmetric flow or turbulence exist. In this paper, a 3D (Three dimensional) isosceles triangular ultrasonic path is presented considering width of ultrasonic signal and the maximum coverage rate of ultrasonic path to flow field. To evaluate the feasibility and effectiveness of the path proposed, computational fluid dynamics (CFD) simulations of three pipeline configurations including straight pipeline, single elbow and contracted pipeline upstream ultrasonic flowmeter 3Dpipe (Diameter of pipeline, Dpipe), 5Dpipe or 8Dpipe long are performed. Specially, inlet velocity of flow ranges from 0.1m/s to 10m/s. Meanwhile, control simulation of U-type ultrasonic path is discussed to verify the effect of coverage rate of ultrasonic path to flow field on measurement results. It is shown that the proposed 3D isosceles triangular ultrasonic path whose coverage rate is 54% does well in improving the stability and accuracy of measurement results while pipeline configuration upstream flowmeter changes. View full abstract»

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  • Occupancy Detection at Smart Home Using Real Time Dynamic Thresholding of Flexiforce Sensor

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (581 KB)  

    Monitoring of the activities of the occupant is paramount important in the field of ambient assisted living environment. Sensors are widely used to collect, store and analyze on the continuous stream of data of the observation of their day-to-day activities. The output of any sensor may gradually change with time. It may come to a point where it becomes difficult to make a distinction between different situations from the sensor’s output. Due to the change of sensor’s output with time it is hard for the system to discriminate very accurately between the regular states and irregular states. This paper deals with the problems faced with the output of flexi-force sensors that happens when the sensor is in operation for a long period to monitor the activities of the inhabitant. A real-time dynamic thresholding has been designed and introduced to identify different situations clearly and avoid confusions regarding the output of the sensor used. View full abstract»

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  • A Method for Uncertainty Assessment of Passive Sun-Induced Chlorophyll Fluorescence Retrieval by Using an Infrared Reference Light

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (920 KB)  

    Measurements of sun-induced chlorophyll fluorescence (SIF) over plant canopies provide a proxy for plant photosynthetic capacity and are of high interest for plant research. Together with spectral reflectance, SIF has the potential to act as a non-invasive approach to quantify photosynthetic plant traits from field to air- and spaceborne scales. But SIF is a small signal contribution to the reflected sunlight and often not distinguishable from sensor noise. SIF estimation is, therefore, affected by an unquantified uncertainty, making it difficult to estimate accurately how much SIF is truly emitted from the plant. To investigate and overcome this, we designed a device based on a spectrometer covering the visible range and equipped it with an LED emitting at the wavelength of SIF. Using this as a reference and applying thorough calibrations, we present consistent evidence of the instrument’s capability of SIF retrieval and accuracy estimations. The LED’s intensity was measured under sunlight with 1.27 ± 0.27 mW×sr-1m-2nm-1 stable over the day. The large increase of SIF due to the Kautsky effect was measured spectrally and temporally proving the biophysical origin of the signal. We propose rigorous tests for instruments intended to measure SIF and show ways to further improve the presented methods. View full abstract»

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  • Fusion predictors for multi-sensor stochastic uncertain systems with missing measurements and unknown measurement disturbances

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (278 KB)  

    This paper addresses the information fusion state estimation problem for multi-sensor stochastic uncertain systems with missing measurements and unknown measurement disturbances. The missing measurements of sensors are described by Bernoulli distributed random variables. Measurements of sensors are subject to external disturbances whose any prior information is unknown. Stochastic parameter uncertainties of systems are depicted by multiplicative noises. For such complex systems with multiple sensors, the Kalman-like centralized fusion and distributed fusion state one-step predictors (i.e., prior filters) independent of unknown measurement disturbances are designed based on the linear unbiased minimum variance criterion, respectively. Estimation error cross-covariance matrices between any two local predictors are derived. Their steady-state properties are analyzed. The sufficient conditions for the existence of the steady-state predictors are given. Two simulation examples show the effectiveness of the proposed algorithms. View full abstract»

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  • Characterization of Different Microsoft Kinect Sensor Models

    Publication Year: 2015 , Page(s): 1
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    This experimental study investigates the performance of three different models of the Microsoft Kinect sensor using the OpenNI driver from Primesense. The accuracy, repeatability, and resolution of the different Kinect models’ abilities to determine the distance to a planar target was explored. An ANOVA analysis was performed to determine if the model of the Kinect, the operating temperature, or their interaction were significant factors in the Kinect’s ability to determine the distance to the target. Different sized gauge blocks were also used to test how well a Kinect could reconstruct precise objects. Machinist blocks were used to examine how well the Kinect could reconstruct objects setup on an angle and determine the location of the center of a hole. All the Kinect models were able to determine the location of a target with a low standard deviation (< 2 mm). At close distances, the resolutions of all the Kinect models were 1 mm. Through the ANOVA analysis, the best performing Kinect at close distances was the Kinect model 1414, and at farther distances was the Kinect model 1473 .The internal temperature of the Kinect sensor had an effect on the distance reported by the sensor. Using different correction factors, the Kinect was able to determine the volume of a gauge block and the angles machinist blocks were setup at, with under a 10 percent error. View full abstract»

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  • An Algorithm for the Automatic Analysis of Signals from an Oyster Heart Rate Sensor

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1692 KB)  

    An in situ optical oyster heart rate sensor generates signals requiring frequency estimation with properties different to human ECG and speech signals. We discuss the method of signal generation and highlight a number of these signal properties. An optimal heart rate estimation approach was identified by application of a variety of frequency estimation techniques and comparing results to manually acquired values. Although a machine learning approach achieved the best performance, accurately estimating 96.8% of the heart rates correctly, a median filtered autocorrelation approach achieved 93.7% with significantly less computational requirement. A method for estimating heart rate variation is also presented. View full abstract»

    Open Access
  • Temperature Drift Compensation Using Multiple Linear Regression for a W-band Total Power Radiometer

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (794 KB)  

    Calibration of radiometer systems using physical temperature monitoring have been developed to compensate the temperature drift. Because calibration standards are not necessary to obtain the system response characteristic, it is good candidate for applications of the limited weight and power. Besides, the estimation of the calibration accuracy could be improved by stable condition based on multiple temperature sensors. In this paper, we analyzed the estimated calibration accuracy under indoor environmental conditions using multiple temperature sensors for a W-band direct detection radiometer system. The method was implemented to obtain the radiometer calibration coefficient based on the relationship between the temperature sensors at multiple positions and the gain variation. The estimated accuracy of the brightness temperature was determined by the temperature sensor response with respect to the receiver gain variation under environmental conditions. The distributed temperature sensors were considered for optimum regression of the radiometer gain variation in a heated environment. View full abstract»

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  • Review of Imprinted Polymer Microring as Ultrasound Detector: Fabrication, characterization and Applications

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (860 KB)  

    Detectors play a vital role in ultrasound sensing and imaging applications. With the rapid development of photoacoustic imaging technology in recent years, novel ultrasound detectors based on optical methods have gained increased attention, among which the imprinted polymer microring is a representative one. This review covers the device design, fabrication and characterization, with an emphasis on how the imprinting-based fabrication methodology benefits the device performance, which further facilitates photoacoustic imaging and sensing applications. By carefully designing and fabricating the imprint mold, the imprinted polymer microring has a quality factor on the order of 105 at 780 nm. The device has advantages such as wide acoustic bandwidth response from DC to 350 MHz at -3 dB, low noise equivalent detectable pressure, wide acceptance angle, etc. The polymer microring has been successfully employed in applications such as photoacoustic imaging, real time terahertz pulse detection, etc. View full abstract»

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  • Simulation of Circular Shaped PZT-5H sensor for Train Measurement using COMSOL Multiphysics

    Publication Year: 2015 , Page(s): 1
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    Simulation of circular piezoelectric sensor for detection of sound pressure inside the rail tracks are investigated and compared with rectangular shaped designs. In the modern era of technological advance world, it is required to implement new ideas. This paper is presenting the new way of detecting train on tracks by measuring the sound waves inside rail tracks. The sound waves are induced inside the railway tracks due to the rolling noise. These longitudinal acoustic wave travels inside railway tracks with a speed of 5960 m/s, which is 17 times faster than the speed of sound in air and may be used for actuating barriers and other warning devices at level crossings. As the output of piezoelectric sensor is voltage signal, it may also be used as energy harvesting device and this stored energy may be used to deliver the power to electronics circuit associated with sensor. Different circular piezoelectric (Lead Zirconate Titanate PZT 5H) sensors are investigated by using simulations in COMSOL. The results of these simulations are used to find out the optimized solution for detection of pressure inside the rail tracks. View full abstract»

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  • Distributed Joint Source-Channel Coding with Copula-Function-Based Correlation Modeling for Wireless Sensors Measuring Temperature

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2311 KB)  

    Wireless sensor networks (WSNs) deployed for temperature monitoring in indoor environments call for systems that perform efficient compression and reliable transmission of the measurements. This is known to be a challenging problem in such deployments, as highly-efficient compression mechanisms impose a high computational cost at the encoder. In this paper, we propose a new distributed joint source-channel coding (DJSCC) solution for this problem. Our design allows for efficient compression and error-resilient transmission, with low computational complexity at the sensor. A new Slepian-Wolf code construction, based on non-systematic Raptor codes, is devised that achieves good performance at short code lengths, which are appropriate for temperature monitoring applications. A key contribution of the work is a novel Copula-function-based modeling approach that accurately expresses the correlation amongst the temperature readings from co-located sensors. Experimental results using a WSN deployment reveal that, for lossless compression, the proposed Copula-function-based model leads to a notable encoding rate reduction (of up to 17.56%) compared to the stateof- the-art model in the literature. Using the proposed model, our DJSCC system achieves significant rate savings (up to 41.81%) against a baseline system that performs arithmetic entropy encoding of the measurements. Moreover, under channel losses, the transmission rate reduction against the state-of-the-art model reaches 19.64%, which leads to energy savings between 18.68% to 24.36% with respect to the baseline system. View full abstract»

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  • Objective Evaluation Criteria for Stereo Camera Shooting Quality under Different Shooting Parameters and Shooting Distances

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2679 KB)  

    The vigorous development of three-dimensional (3D) technology has improved the photography technology of stereo cameras constantly. However, there are no widely recognized objective evaluation criteria for stereo camera shooting quality under different shooting parameters and shooting distances. At the same time, no shooting guideline can be used for reference when people take stereoscopic images. To solve this problem, we propose the objective evaluation criteria of shooting quality of two types of stereo cameras (parallel and toed-in camera configurations) under three shooting conditions (macro shooting, short and long distance shooting). In our work, several prominent evaluation factors are built by analyzing the characteristics of each shooting condition. Based on the effective five-point scale used in our subjective experiments, the relationships between shooting factors and shooting quality are obtained and then effectively integrated together to build the overall evaluation criteria. Finally, extensive experiments have been conducted, and the results demonstrate that the proposed approach can effectively evaluate the shooting quality of stereo cameras. View full abstract»

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  • Blood Pulsation Measurement using Linearly Polarized Light

    Publication Year: 2015 , Page(s): 1
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    Blood molecules are optically active molecules. They have the ability to alter the polarization properties of light. This paper investigates the effect of blood pulsation variation on the polarization properties of linearly polarized light. The paper presents a new non-invasive non-contact blood pulsation measurement technique. Linearly polarized light has been allowed to transmit through the fingertips of a person and degree of linear polarization for transmitted part of the light has been calculated using polarized images. Experimental results show a strong correlation between the blood pulsation rate and the measured degree of linear polarization. The standard correlation coefficient value for the experiment with laser light source and two polarizers in the light path is 0.9484. Similarly for DC light source the correlation coefficient values are 0.9410 and 0.92 with two polarizers and one polarizer respectively. Statistical analysis of the collected data has been done to measure the accuracy of the method. It shows that an accurate, low cost and simple polarization based blood pulsation measurement device can be developed by following the experiment performed with laser light source which could offer significant benefits to primary healthcare. View full abstract»

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  • Resolving Multipath Interference in Kinect: An Inverse Problem Approach

    Publication Year: 2015 , Page(s): 1
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    Multi-path interference is an inherent unsolved problem in amplitude modulated continuous wave (AMCW) Time-of-Flight imaging that results in erroneous depth and amplitude measurements. This kind of interference is the result of light which travels along different optical paths and reaches the same pixel. Important scenarios with strong interference include scenes with highly reflective surfaces, imaging through translucent material, subsurface scattering and imaging a corner. In this work, we demonstrate that multiple frequency measurements made with a non-customized Kinect for the XBox One (the new Kinect) camera can be used to resolve the interfering paths. By formulating our problem as a spectral estimation problem, we provide a closed-form, non-iterative technique. View full abstract»

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  • Convergence Analysis for Regular Wireless Consensus Networks

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (536 KB)  

    Average consensus algorithms can be implemented over wireless sensor networks (WSN), where global statistics can be computed using communications among sensor nodes locally. Simple execution, robustness to global topology changes due to frequent node failures and underlying distributed philosophy have made consensus algorithms more suitable to WSNs. Since these algorithms are iterative in nature, it is very difficult to predict the convergence time of the average consensus algorithm on WSNs. We study the convergence of the average consensus algorithms for WSNs using distance regular graphs. We have obtained the analytical expressions for optimal consensus parameter and optimal convergence parameter which estimates the convergence time for r-nearest neighbor cycle and torus networks. We have also derived the generalized expression for optimal consensus parameter and optimal convergence parameter for mdimensional r-nearest neighbor torus networks. The obtained analytical results agree with the simulation results and shown the effect of network dimension, number of nodes and nearest neighbors on convergence time. This work provides the basic analytical tools for managing and controlling the performance of average consensus algorithms over finite sized practical WSNs. View full abstract»

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  • Wireless Biosensing Using Silver-Enhancement Based Self-assembled Antennas in Passive Radio Frequency Identification (RFID) Tags

    Publication Year: 2015 , Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5404 KB)  

    In this paper, we present a silver-enhancement technique for self-assembling radio-frequency (RF) antennas and demonstrate its application for remote biosensing. When target analytes or pathogens are present in a sample the silverenhancement process self-assembles a chain of micro-monopole antennas. As the size of the silver-enhanced particles grows, the chain of micro-antenna segments bridge together to complete a macro-antenna structure. The change in the electrical impedance across the bridge modulates the reflection properties of the antenna at a desired frequency. In this paper we have used this principle to model, optimize and design a ratiometric mode 915 MHz radio-frequency identification (RFID) based biosensor which uses relative received signal strength indicator (RSSI) to measure and detect different concentration levels of target analytes. We have validated the proof-of-concept for detecting two types of analytes: (a) IgG in rabbit serum at concentration levels ranging from 20 ng to 60 ng; and (b) moisture in a sample at volumes ranging from 5l to 40l. A significant advantage of the proposed biosensor is that the concentration level of target analytes or pathogens can be remotely interrogated in a concealed, packaged or in a bio-hazardous environment, where direct electrical or optical measurement is considered to be impractical. View full abstract»

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  • Compact Personal Distributed Wearable Exposimeter

    Publication Year: 2015 , Page(s): 1
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    A compact wearable Personal Distributed Exposimeter is proposed, sensing the power density of incident radio-frequency (RF) fields on the body of a human. In contrast to current commercial exposimeters, our Personal Distributed Exposimeter, being composed of multiple compact personal wearable RF exposimeter sensor modules, minimizes uncertainties caused by the proximity of the body, the specific antenna used and the exact position of the exposimeter. For unobtrusive deployment inside a jacket, each individual exposimeter sensor module is specifically implemented on the feedplane of a textile patch antenna. The new wearable sensor module’s high-resolution logarithmic detector logs RF signal levels. Next, on-board flash memory records minimum, maximum and average exposure data over a time span of more than two weeks, at a one-second sample period. Sample-level synchronization of each individual exposimeter sensor module enables combining of measurements collected by different nodes. The system is first calibrated in an anechoic chamber, and then compared to a commercially available single-unit exposimeter. Next, the Personal Distributed Exposimeter is validated in realistic conditions, by measuring the average RF power density on a human during a walk in an urban environment and comparing the results to spectrum analyzer measurements with a calibrated antenna. View full abstract»

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  • A 3D Ad Hoc Localization System using Aerial Sensor Nodes

    Publication Year: 2015 , Page(s): 1
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    An ad hoc localization system (AHLoS) is necessary at a time or place where Global Satellite Navigation Systems are not available and a permanent infrastructure is not needed. Previous work on such systems has typically focused on 2D horizontal navigation, but new applications such as those for Unmanned Aerial Systems (UAS) require a 3D navigation capability. In this paper, we present an AHLoS utilizing aerial nodes in the form of quadrotors or similar platforms in addition to fixed, groundbased nodes to provide a precise 3D positioning capability. The nodes are equipped with Ultra Wide Band devices to be used as ranging sources. Our mathematical analysis and simulated results suggest that the 3D AHLoS is capable of providing high positioning accuracy, most notably, the vertical accuracy that is better than a couple of decimeters for 95 percent of the time, making it ideal for various UAS applications. View full abstract»

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Aims & Scope

The IEEE Sensors Journal is a peer-reviewed, monthly online/print  journal devoted to sensors and sensing phenomena

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Meet Our Editors

Editor-in-Chief
Krikor Ozanyan
University of Manchester
Manchester, M13 9PL, U.K.