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Sensors, Volume 11, Issue 12 (December 2011) – 49 articles , Pages 11036-11920

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421 KiB  
Article
Contamination of Runoff Water at Gdańsk Airport (Poland) by Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs)
by Anna Maria Sulej, Żaneta Polkowska and Jacek Namieśnik
Sensors 2011, 11(12), 11901-11920; https://doi.org/10.3390/s111211901 - 20 Dec 2011
Cited by 26 | Viewed by 9939
Abstract
Airport runoff can contain high concentrations of various pollutants, in particular polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), the environmental levels of which have to be monitored. Airport runoff water samples, collected at the Gdańsk-Rębiechowo Airport from 2008 to 2009, were [...] Read more.
Airport runoff can contain high concentrations of various pollutants, in particular polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), the environmental levels of which have to be monitored. Airport runoff water samples, collected at the Gdańsk-Rębiechowo Airport from 2008 to 2009, were analysed for PAHs and PCBs by gas chromatography. The aromatic fractions were separated by liquid-liquid extraction and analysed by GC/MS. Total PAH concentrations were 295–6,758 ng/L in 2008 and 180–1,924 ng/L in 2009, while total PCB levels in 2008 ranged from 0.14 to 0.44 µg/L and in 2009 from 0.06 to 0.23 µg/L. The PAH and PCB compositions in airport runoff waters were examined over a range of spatial and temporal scales to determine distributions, trends and possible sources. This pollution is mainly pyrolytic and related to anthropogenic activity. There were significant differences between the samples collected in the two seasons. An understanding of the magnitude of contamination due to airport runoff water is important for the effective management of airport infrastructure. Full article
(This article belongs to the Special Issue Sensing of Organic Pollution in Soil, Air, Water and Food)
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17483 KiB  
Article
Robust and Cooperative Image-Based Visual Servoing System Using a Redundant Architecture
by Nicolas Garcia-Aracil, Carlos Perez-Vidal, Jose Maria Sabater, Ricardo Morales and Francisco J. Badesa
Sensors 2011, 11(12), 11885-11900; https://doi.org/10.3390/s111211885 - 20 Dec 2011
Cited by 12 | Viewed by 7839
Abstract
The reliability and robustness of image-based visual servoing systems is still unsolved by the moment. In order to address this issue, a redundant and cooperative 2D visual servoing system based on the information provided by two cameras in eye-in-hand/eye-to-hand configurations is proposed. Its [...] Read more.
The reliability and robustness of image-based visual servoing systems is still unsolved by the moment. In order to address this issue, a redundant and cooperative 2D visual servoing system based on the information provided by two cameras in eye-in-hand/eye-to-hand configurations is proposed. Its control law has been defined to assure that the whole system is stable if each subsystem is stable and to allow avoiding typical problems of image-based visual servoing systems like task singularities, features extraction errors, disappearance of image features, local minima, etc. Experimental results with an industrial robot manipulator based on Schunk modular motors to demonstrate the stability, performance and robustness of the proposed system are presented. Full article
(This article belongs to the Section Physical Sensors)
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633 KiB  
Article
Advances in SAW Gas Sensors Based on the Condensate-Adsorption Effect
by Jiuling Liu, Wen Wang, Shunzhou Li, Minghua Liu and Shitang He
Sensors 2011, 11(12), 11871-11884; https://doi.org/10.3390/s111211871 - 20 Dec 2011
Cited by 30 | Viewed by 8683
Abstract
A surface-acoustic-wave (SAW) gas sensor with a low detection limit and fast response for volatile organic compounds (VOCs) based on the condensate-adsorption effect detection is developed. In this sensor a gas chromatography (GC) column acts as the separator element and a dual-resonator oscillator [...] Read more.
A surface-acoustic-wave (SAW) gas sensor with a low detection limit and fast response for volatile organic compounds (VOCs) based on the condensate-adsorption effect detection is developed. In this sensor a gas chromatography (GC) column acts as the separator element and a dual-resonator oscillator acts as the detector element. Regarding the surface effective permittivity method, the response mechanism analysis, which relates the condensate-adsorption effect, is performed, leading to the sensor performance prediction prior to fabrication. New designs of SAW resonators, which act as feedback of the oscillator, are devised in order to decrease the insertion loss and to achieve single-mode control, resulting in superior frequency stability of the oscillator. Based on the new phase modulation approach, excellent short-term frequency stability (±3 Hz/s) is achieved with the SAW oscillator by using the 500 MHz dual-port resonator as feedback element. In a sensor experiment investigating formaldehyde detection, the implemented SAW gas sensor exhibits an excellent threshold detection limit as low as 0.38 pg. Full article
(This article belongs to the Section Physical Sensors)
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871 KiB  
Article
Characterization of a Low-Cost Optical Flow Sensor When Using an External Laser as a Direct Illumination Source
by Davinia Font, Marcel Tresanchez, Tomàs Pallejà, Mercè Teixidó and Jordi Palacín
Sensors 2011, 11(12), 11856-11870; https://doi.org/10.3390/s111211856 - 20 Dec 2011
Cited by 10 | Viewed by 10113
Abstract
In this paper, a low cost optical flow sensor is combined with an external laser device to measure surface displacements and mechanical oscillations. The measurement system is based on applying coherent light to a diffuser surface and using an optical flow sensor to [...] Read more.
In this paper, a low cost optical flow sensor is combined with an external laser device to measure surface displacements and mechanical oscillations. The measurement system is based on applying coherent light to a diffuser surface and using an optical flow sensor to analyze the reflected and transferred light to estimate the displacement of the surface or the laser spot. This work is focused on the characterization of this measurement system, which can have the optical flow sensor placed at different angles and distances from the diffuser surface. The results have shown that the displacement of the diffuser surface is badly estimated when the optical mouse sensor is placed in front of the diffuser surface (angular orientation >150°) while the highest sensitivity is obtained when the sensor is located behind the diffuser surface and on the axis of the laser source (angular orientation 0°). In this case, the coefficient of determination of the measured displacement, R2, was very high (>0.99) with a relative error of less than 1.29%. Increasing the distance between the surface and the sensor also increased the sensitivity which increases linearly, R2 = 0.99. Finally, this measurement setup was proposed to measure very low frequency mechanical oscillations applied to the laser device, up to 0.01 Hz in this work. The results have shown that increasing the distance between the surface and the optical flow sensor also increases the sensitivity and the measurement range. Full article
(This article belongs to the Special Issue Ultra-Small Sensor Systems and Components)
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1948 KiB  
Article
A Query Result Merging Scheme for Providing Energy Efficiency in Underwater Sensor Networks
by Yunsung Kim and Soo-Hyun Park
Sensors 2011, 11(12), 11833-11855; https://doi.org/10.3390/s111211833 - 20 Dec 2011
Cited by 8 | Viewed by 8098
Abstract
Underwater sensor networks are emerging as a promising distributed data management system for various applications in underwater environments, despite their limited accessibility and restricted energy capacity. With the aid of recent developments in ubiquitous data computing, an increasing number of users are expected [...] Read more.
Underwater sensor networks are emerging as a promising distributed data management system for various applications in underwater environments, despite their limited accessibility and restricted energy capacity. With the aid of recent developments in ubiquitous data computing, an increasing number of users are expected to overcome low accessibility by applying queries to underwater sensor networks. However, when multiple users send queries to an underwater sensor network in a disorganized manner, it may incur lethal energy waste and problematic network traffic. The current query management mechanisms cannot effectively deal with this matter due to their limited applicability and unrealistic assumptions. In this paper, a novel query management scheme involving query result merging is proposed for underwater sensor networks. The mechanism is based on a relational database model and is adjusted to the practical restrictions affecting underwater communication environments. Network simulations will prove that the scheme becomes more efficient with a greater number of queries and a smaller period range. Full article
(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)
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676 KiB  
Article
Surface Acoustic Wave (SAW) Vibration Sensors
by Jerzy Filipiak, Lech Solarz and Grzegorz Steczko
Sensors 2011, 11(12), 11809-11832; https://doi.org/10.3390/s111211809 - 19 Dec 2011
Cited by 29 | Viewed by 9859
Abstract
In the paper a feasibility study on the use of surface acoustic wave (SAW) vibration sensors for electronic warning systems is presented. The system is assembled from concatenated SAW vibration sensors based on a SAW delay line manufactured on a surface of a [...] Read more.
In the paper a feasibility study on the use of surface acoustic wave (SAW) vibration sensors for electronic warning systems is presented. The system is assembled from concatenated SAW vibration sensors based on a SAW delay line manufactured on a surface of a piezoelectric plate. Vibrations of the plate are transformed into electric signals that allow identification of the sensor and localization of a threat. The theoretical study of sensor vibrations leads us to the simple isotropic model with one degree of freedom. This model allowed an explicit description of the sensor plate movement and identification of the vibrating sensor. Analysis of frequency response of the ST-cut quartz sensor plate and a damping speed of its impulse response has been conducted. The analysis above was the basis to determine the ranges of parameters for vibrating plates to be useful in electronic warning systems. Generally, operation of electronic warning systems with SAW vibration sensors is based on the analysis of signal phase changes at the working frequency of delay line after being transmitted via two circuits of concatenated four-terminal networks. Frequencies of phase changes are equal to resonance frequencies of vibrating plates of sensors. The amplitude of these phase changes is proportional to the amplitude of vibrations of a sensor plate. Both pieces of information may be sent and recorded jointly by a simple electrical unit. Full article
(This article belongs to the Special Issue Emerging Acoustic Wave-Based Sensors)
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6714 KiB  
Review
Electromagnetic Imaging Methods for Nondestructive Evaluation Applications
by Yiming Deng and Xin Liu
Sensors 2011, 11(12), 11774-11808; https://doi.org/10.3390/s111211774 - 19 Dec 2011
Cited by 90 | Viewed by 13519
Abstract
Electromagnetic nondestructive tests are important and widely used within the field of nondestructive evaluation (NDE). The recent advances in sensing technology, hardware and software development dedicated to imaging and image processing, and material sciences have greatly expanded the application fields, sophisticated the systems [...] Read more.
Electromagnetic nondestructive tests are important and widely used within the field of nondestructive evaluation (NDE). The recent advances in sensing technology, hardware and software development dedicated to imaging and image processing, and material sciences have greatly expanded the application fields, sophisticated the systems design and made the potential of electromagnetic NDE imaging seemingly unlimited. This review provides a comprehensive summary of research works on electromagnetic imaging methods for NDE applications, followed by the summary and discussions on future directions. Full article
(This article belongs to the Section Physical Sensors)
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780 KiB  
Article
Force to Rebalance Control of HRG and Suppression of Its Errors on the Basis of FPGA
by Xu Wang, Wenqi Wu, Bing Luo, Zhen Fang, Yun Li and Qingan Jiang
Sensors 2011, 11(12), 11761-11773; https://doi.org/10.3390/s111211761 - 16 Dec 2011
Cited by 41 | Viewed by 10553
Abstract
A novel design of force to rebalance control for a hemispherical resonator gyro (HRG) based on FPGA is demonstrated in this paper. The proposed design takes advantage of the automatic gain control loop and phase lock loop configuration in the drive mode while [...] Read more.
A novel design of force to rebalance control for a hemispherical resonator gyro (HRG) based on FPGA is demonstrated in this paper. The proposed design takes advantage of the automatic gain control loop and phase lock loop configuration in the drive mode while making full use of the quadrature control loop and rebalance control loop in controlling the oscillating dynamics in the sense mode. First, the math model of HRG with inhomogeneous damping and frequency split is theoretically analyzed. In addition, the major drift mechanisms in the HRG are described and the methods that can suppress the gyro drift are mentioned. Based on the math model and drift mechanisms suppression method, four control loops are employed to realize the manipulation of the HRG by using a FPGA circuit. The reference-phase loop and amplitude control loop are used to maintain the vibration of primary mode at its natural frequency with constant amplitude. The frequency split is readily eliminated by the quadrature loop with a DC voltage feedback from the quadrature component of the node. The secondary mode response to the angle rate input is nullified by the rebalance control loop. In order to validate the effect of the digital control of HRG, experiments are carried out with a turntable. The experimental results show that the design is suitable for the control of HRG which has good linearity scale factor and bias stability. Full article
(This article belongs to the Special Issue Collaborative Sensors)
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248 KiB  
Article
Low Cost Sensors Based on SPR in a Plastic Optical Fiber for Biosensor Implementation
by Nunzio Cennamo, Davide Massarotti, Laura Conte and Luigi Zeni
Sensors 2011, 11(12), 11752-11760; https://doi.org/10.3390/s111211752 - 16 Dec 2011
Cited by 285 | Viewed by 12428
Abstract
This paper reports the fabrication and testing of two configurations of optical sensor systems based on Surface Plasmon Resonance (SPR) at the interface of a liquid sample and sandwiched structures realized starting from the exposed core of a Plastic Optical Fiber (POF). The [...] Read more.
This paper reports the fabrication and testing of two configurations of optical sensor systems based on Surface Plasmon Resonance (SPR) at the interface of a liquid sample and sandwiched structures realized starting from the exposed core of a Plastic Optical Fiber (POF). The proposed geometries have proven to be suitable for measuring the refractive indexes of liquids whose refractive index falls around 1.35. Furthermore, the proposed sensing head, being low cost and relatively easy to realize, may be very attractive for biosensor implementation. Full article
(This article belongs to the Section Biosensors)
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457 KiB  
Review
Semiconductor Quantum Dots for Biomedicial Applications
by Lijia Shao, Yanfang Gao and Feng Yan
Sensors 2011, 11(12), 11736-11751; https://doi.org/10.3390/s111211736 - 16 Dec 2011
Cited by 166 | Viewed by 14631
Abstract
Semiconductor quantum dots (QDs) are nanometre-scale crystals, which have unique photophysical properties, such as size-dependent optical properties, high fluorescence quantum yields, and excellent stability against photobleaching. These properties enable QDs as the promising optical labels for the biological applications, such as multiplexed analysis [...] Read more.
Semiconductor quantum dots (QDs) are nanometre-scale crystals, which have unique photophysical properties, such as size-dependent optical properties, high fluorescence quantum yields, and excellent stability against photobleaching. These properties enable QDs as the promising optical labels for the biological applications, such as multiplexed analysis of immunocomplexes or DNA hybridization processes, cell sorting and tracing, in vivo imaging and diagnostics in biomedicine. Meanwhile, QDs can be used as labels for the electrochemical detection of DNA or proteins. This article reviews the synthesis and toxicity of QDs and their optical and electrochemical bioanalytical applications. Especially the application of QDs in biomedicine such as delivering, cell targeting and imaging for cancer research, and in vivo photodynamic therapy (PDT) of cancer are briefly discussed. Full article
(This article belongs to the Special Issue Sensing with Quantum Dots)
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638 KiB  
Article
A Cost Effective Block Framing Scheme for Underwater Communication
by Soo-Young Shin and Soo-Hyun Park
Sensors 2011, 11(12), 11717-11735; https://doi.org/10.3390/s111211717 - 16 Dec 2011
Cited by 5 | Viewed by 7594
Abstract
In this paper, the Selective Multiple Acknowledgement (SMA) method, based on Multiple Acknowledgement (MA), is proposed to efficiently reduce the amount of data transmission by redesigning the transmission frame structure and taking into consideration underwater transmission characteristics. The method is suited to integrated [...] Read more.
In this paper, the Selective Multiple Acknowledgement (SMA) method, based on Multiple Acknowledgement (MA), is proposed to efficiently reduce the amount of data transmission by redesigning the transmission frame structure and taking into consideration underwater transmission characteristics. The method is suited to integrated underwater system models, as the proposed method can handle the same amount of data in a much more compact frame structure without any appreciable loss of reliability. Herein, the performance of the proposed SMA method was analyzed and compared to those of the conventional Automatic Repeat-reQuest (ARQ), Block Acknowledgement (BA), block response, and MA methods. The efficiency of the underwater sensor network, which forms a large cluster and mostly contains uplink data, is expected to be improved by the proposed method. Full article
(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)
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258 KiB  
Review
The Need and Potential of Biosensors to Detect Dioxins and Dioxin-Like Polychlorinated Biphenyls along the Milk, Eggs and Meat Food Chain
by Jeerasak Chobtang, Imke J. M. De Boer, Ron L. A. P. Hoogenboom, Willem Haasnoot, Aize Kijlstra and Bastiaan G. Meerburg
Sensors 2011, 11(12), 11692-11716; https://doi.org/10.3390/s111211692 - 15 Dec 2011
Cited by 40 | Viewed by 12970
Abstract
Dioxins and dioxin-like polychlorinated biphenyls (DL-PCBs) are hazardous toxic, ubiquitous and persistent chemical compounds, which can enter the food chain and accumulate up to higher trophic levels. Their determination requires sophisticated methods, expensive facilities and instruments, well-trained personnel and expensive chemical reagents. Ideally, [...] Read more.
Dioxins and dioxin-like polychlorinated biphenyls (DL-PCBs) are hazardous toxic, ubiquitous and persistent chemical compounds, which can enter the food chain and accumulate up to higher trophic levels. Their determination requires sophisticated methods, expensive facilities and instruments, well-trained personnel and expensive chemical reagents. Ideally, real-time monitoring using rapid detection methods should be applied to detect possible contamination along the food chain in order to prevent human exposure. Sensor technology may be promising in this respect. This review gives the state of the art for detecting possible contamination with dioxins and DL-PCBs along the food chain of animal-source foods. The main detection methods applied (i.e., high resolution gas-chromatography combined with high resolution mass-spectrometry (HRGC/HRMS) and the chemical activated luciferase gene expression method (CALUX bioassay)), each have their limitations. Biosensors for detecting dioxins and related compounds, although still under development, show potential to overcome these limitations. Immunosensors and biomimetic-based biosensors potentially offer increased selectivity and sensitivity for dioxin and DL-PCB detection, while whole cell-based biosensors present interpretable biological results. The main shortcoming of current biosensors, however, is their detection level: this may be insufficient as limits for dioxins and DL-PCBs for food and feedstuffs are in pg per gram level. In addition, these contaminants are normally present in fat, a difficult matrix for biosensor detection. Therefore, simple and efficient extraction and clean-up procedures are required which may enable biosensors to detect dioxins and DL-PCBs contamination along the food chain. Full article
(This article belongs to the Special Issue Sensing of Organic Pollution in Soil, Air, Water and Food)
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476 KiB  
Article
Amperometric Immunosensor Based on a Protein A/Deposited Gold Nanocrystals Modified Electrode for Carbofuran Detection
by Xia Sun, Ying Zhu and Xiangyou Wang
Sensors 2011, 11(12), 11679-11691; https://doi.org/10.3390/s111211679 - 15 Dec 2011
Cited by 26 | Viewed by 8067
Abstract
In this paper, an amperometric immunosensor modified with protein A/deposited gold nanocrystals (DpAu) was developed for the ultrasensitive detection of carbofuran residues. First, DpAu were electrodeposited onto the Au electrode surface to absorb protein A (PA) and improve the electrode conductivity. Then PA [...] Read more.
In this paper, an amperometric immunosensor modified with protein A/deposited gold nanocrystals (DpAu) was developed for the ultrasensitive detection of carbofuran residues. First, DpAu were electrodeposited onto the Au electrode surface to absorb protein A (PA) and improve the electrode conductivity. Then PA was dropped onto the surface of DpAu film, used for binding antibody Fc fragments. Next, anti-carbofuran monoclonal antibody was immobilized on the PA modified electrode. Finally, bovine serum albumin (BSA) was employed to block the possible remaining active sites avoiding any nonspecific adsorption. The fabrication procedure of the immunosensor was characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), respectively. With the excellent electroconductivity of DpAu and the PA’s oriented immobilization of antibodies, a highly efficient immuno-reaction and detection sensitivity could be achieved. The influences of the electrodeposition time of DpAu, pH of the detection solution and incubation time on the current response of the fabricated immunosensor were investigated. Under optimized conditions, the current response was proportional to the concentration of carbofuran which ranged from 1 to 100 ng/mL and 100 ng/mL to 100 μg/mL. The detection limit was 0.1924 ng/mL. The proposed carbofuran immnuosensor exhibited high specificity, reproducibility, stability and regeneration performance, which may open a new door for ultrasensitive detection of carbofuran residues in vegetables and fruits. Full article
(This article belongs to the Section Biosensors)
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1649 KiB  
Review
CdTe and CdSe Quantum Dots Cytotoxicity: A Comparative Study on Microorganisms
by Suzete A.O. Gomes, Cecilia Stahl Vieira, Diogo B. Almeida, Jacenir R. Santos-Mallet, Rubem F. S. Menna-Barreto, Carlos L. Cesar and Denise Feder
Sensors 2011, 11(12), 11664-11678; https://doi.org/10.3390/s111211664 - 15 Dec 2011
Cited by 67 | Viewed by 11102
Abstract
Quantum dots (QDs) are colloidal semiconductor nanocrystals of a few nanometers in diameter, being their size and shape controlled during the synthesis. They are synthesized from atoms of group II–VI or III–V of the periodic table, such as cadmium telluride (CdTe) or cadmium [...] Read more.
Quantum dots (QDs) are colloidal semiconductor nanocrystals of a few nanometers in diameter, being their size and shape controlled during the synthesis. They are synthesized from atoms of group II–VI or III–V of the periodic table, such as cadmium telluride (CdTe) or cadmium selenium (CdSe) forming nanoparticles with fluorescent characteristics superior to current fluorophores. The excellent optical characteristics of quantum dots make them applied widely in the field of life sciences. Cellular uptake of QDs, location and translocation as well as any biological consequence, such as cytotoxicity, stimulated a lot of scientific research in this area. Several studies pointed to the cytotoxic effect against micoorganisms. In this mini-review, we overviewed the synthesis and optical properties of QDs, and its advantages and bioapplications in the studies about microorganisms such as protozoa, bacteria, fungi and virus. Full article
(This article belongs to the Special Issue Sensing with Quantum Dots)
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1598 KiB  
Article
Pressure-Sensitive Paint: Effect of Substrate
by Mark Kenneth Quinn, Leichao Yang and Konstantinos Kontis
Sensors 2011, 11(12), 11649-11663; https://doi.org/10.3390/s111211649 - 14 Dec 2011
Cited by 42 | Viewed by 8983
Abstract
There are numerous ways in which pressure-sensitive paint can be applied to a surface. The choice of substrate and application method can greatly affect the results obtained. The current study examines the different methods of applying pressure-sensitive paint to a surface. One polymer-based [...] Read more.
There are numerous ways in which pressure-sensitive paint can be applied to a surface. The choice of substrate and application method can greatly affect the results obtained. The current study examines the different methods of applying pressure-sensitive paint to a surface. One polymer-based and two porous substrates (anodized aluminum and thin-layer chromatography plates) are investigated and compared for luminescent output, pressure sensitivity, temperature sensitivity and photodegradation. Two luminophores [tris-Bathophenanthroline Ruthenium(II) Perchlorate and Platinum-tetrakis (pentafluorophenyl) Porphyrin] will also be compared in all three of the substrates. The results show the applicability of the different substrates and luminophores to different testing environments. Full article
(This article belongs to the Section Physical Sensors)
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1583 KiB  
Article
Development of a Multisensor-Based Bio-Botanic Robot and Its Implementation Using a Self-Designed Embedded Board
by Chung-Liang Chang, Ming-Fong Sie and Jin-Long Shie
Sensors 2011, 11(12), 11629-11648; https://doi.org/10.3390/s111211629 - 13 Dec 2011
Cited by 2 | Viewed by 9048
Abstract
This paper presents the design concept of a bio-botanic robot which demonstrates its behavior based on plant growth. Besides, it can reflect the different phases of plant growth depending on the proportional amounts of light, temperature and water. The mechanism design is made [...] Read more.
This paper presents the design concept of a bio-botanic robot which demonstrates its behavior based on plant growth. Besides, it can reflect the different phases of plant growth depending on the proportional amounts of light, temperature and water. The mechanism design is made up of a processed aluminum base, spring, polydimethylsiloxane (PDMS) and actuator to constitute the plant base and plant body. The control system consists of two micro-controllers and a self-designed embedded development board where the main controller transmits the values of the environmental sensing module within the embedded board to a sub-controller. The sub-controller determines the growth stage, growth height, and time and transmits its decision value to the main controller. Finally, based on the data transmitted by the sub-controller, the main controller controls the growth phase of the bio-botanic robot using a servo motor and leaf actuator. The research result not only helps children realize the variation of plant growth but also is entertainment-educational through its demonstration of the growth process of the bio-botanic robot in a short time. Full article
(This article belongs to the Special Issue Control Systems and Robotics in Bioengineering)
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2571 KiB  
Article
Dynamic Sensing Performance of a Point-Wise Fiber Bragg Grating Displacement Measurement System Integrated in an Active Structural Control System
by Kuo-Chih Chuang, Heng-Tseng Liao and Chien-Ching Ma
Sensors 2011, 11(12), 11605-11628; https://doi.org/10.3390/s111211605 - 13 Dec 2011
Cited by 7 | Viewed by 9790
Abstract
In this work, a fiber Bragg grating (FBG) sensing system which can measure the transient response of out-of-plane point-wise displacement responses is set up on a smart cantilever beam and the feasibility of its use as a feedback sensor in an active structural [...] Read more.
In this work, a fiber Bragg grating (FBG) sensing system which can measure the transient response of out-of-plane point-wise displacement responses is set up on a smart cantilever beam and the feasibility of its use as a feedback sensor in an active structural control system is studied experimentally. An FBG filter is employed in the proposed fiber sensing system to dynamically demodulate the responses obtained by the FBG displacement sensor with high sensitivity. For comparison, a laser Doppler vibrometer (LDV) is utilized simultaneously to verify displacement detection ability of the FBG sensing system. An optical full-field measurement technique called amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) is used to provide full-field vibration mode shapes and resonant frequencies. To verify the dynamic demodulation performance of the FBG filter, a traditional FBG strain sensor calibrated with a strain gauge is first employed to measure the dynamic strain of impact-induced vibrations. Then, system identification of the smart cantilever beam is performed by FBG strain and displacement sensors. Finally, by employing a velocity feedback control algorithm, the feasibility of integrating the proposed FBG displacement sensing system in a collocated feedback system is investigated and excellent dynamic feedback performance is demonstrated. In conclusion, our experiments show that the FBG sensor is capable of performing dynamic displacement feedback and/or strain measurements with high sensitivity and resolution. Full article
(This article belongs to the Special Issue Optical Fiber Sensors 2012)
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934 KiB  
Article
Towards Smart Homes Using Low Level Sensory Data
by Asad Masood Khattak, Phan Tran Ho Truc, Le Xuan Hung, La The Vinh, Viet-Hung Dang, Donghai Guan, Zeeshan Pervez, Manhyung Han, Sungyoung Lee and Young-Koo Lee
Sensors 2011, 11(12), 11581-11604; https://doi.org/10.3390/s111211581 - 12 Dec 2011
Cited by 25 | Viewed by 10429
Abstract
Ubiquitous Life Care (u-Life care) is receiving attention because it provides high quality and low cost care services. To provide spontaneous and robust healthcare services, knowledge of a patient’s real-time daily life activities is required. Context information with real-time daily life activities can [...] Read more.
Ubiquitous Life Care (u-Life care) is receiving attention because it provides high quality and low cost care services. To provide spontaneous and robust healthcare services, knowledge of a patient’s real-time daily life activities is required. Context information with real-time daily life activities can help to provide better services and to improve healthcare delivery. The performance and accuracy of existing life care systems is not reliable, even with a limited number of services. This paper presents a Human Activity Recognition Engine (HARE) that monitors human health as well as activities using heterogeneous sensor technology and processes these activities intelligently on a Cloud platform for providing improved care at low cost. We focus on activity recognition using video-based, wearable sensor-based, and location-based activity recognition engines and then use intelligent processing to analyze the context of the activities performed. The experimental results of all the components showed good accuracy against existing techniques. The system is deployed on Cloud for Alzheimer’s disease patients (as a case study) with four activity recognition engines to identify low level activity from the raw data captured by sensors. These are then manipulated using ontology to infer higher level activities and make decisions about a patient’s activity using patient profile information and customized rules. Full article
(This article belongs to the Section Physical Sensors)
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458 KiB  
Article
ATLAS: A Traffic Load Aware Sensor MAC Design for Collaborative Body Area Sensor Networks
by Md. Obaidur Rahman, Choong Seon Hong, Sungwon Lee and Young-Cheol Bang
Sensors 2011, 11(12), 11560-11580; https://doi.org/10.3390/s111211560 - 12 Dec 2011
Cited by 42 | Viewed by 9488
Abstract
In collaborative body sensor networks, namely wireless body area networks(WBANs), each of the physical sensor applications is used to collaboratively monitor thehealth status of the human body. The applications of WBANs comprise diverse and dynamictraffic loads such as very low-rate periodic monitoring ( [...] Read more.
In collaborative body sensor networks, namely wireless body area networks(WBANs), each of the physical sensor applications is used to collaboratively monitor thehealth status of the human body. The applications of WBANs comprise diverse and dynamictraffic loads such as very low-rate periodic monitoring (i.e., observation) data and high-ratetraffic including event-triggered bursts. Therefore, in designing a medium access control(MAC) protocol for WBANs, energy conservation should be the primary concern duringlow-traffic periods, whereas a balance between satisfying high-throughput demand andefficient energy usage is necessary during high-traffic times. In this paper, we design atraffic load-aware innovative MAC solution for WBANs, called ATLAS. The design exploitsthe superframe structure of the IEEE 802.15.4 standard, and it adaptively uses the contentionaccess period (CAP), contention free period (CFP) and inactive period (IP) of the superframebased on estimated traffic load, by applying a dynamic “wh” (whenever which is required)approach. Unlike earlier work, the proposed MAC design includes load estimation fornetwork load-status awareness and a multi-hop communication pattern in order to preventenergy loss associated with long range transmission. Finally, ATLAS is evaluated throughextensive simulations in ns-2 and the results demonstrate the effectiveness of the protocol. Full article
(This article belongs to the Special Issue Collaborative Sensors)
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2909 KiB  
Article
Heterogeneous Collaborative Sensor Network for Electrical Management of an Automated House with PV Energy
by Manuel Castillo-Cagigal, Eduardo Matallanas, Álvaro Gutiérrez, Félix Monasterio-Huelin, Estefaná Caamaño-Martín, Daniel Masa-Bote and Javier Jiménez-Leube
Sensors 2011, 11(12), 11544-11559; https://doi.org/10.3390/s111211544 - 9 Dec 2011
Cited by 10 | Viewed by 9399
Abstract
In this paper we present a heterogeneous collaborative sensor network for electrical management in the residential sector. Improving demand-side management is very important in distributed energy generation applications. Sensing and control are the foundations of the “Smart Grid” which is the future of [...] Read more.
In this paper we present a heterogeneous collaborative sensor network for electrical management in the residential sector. Improving demand-side management is very important in distributed energy generation applications. Sensing and control are the foundations of the “Smart Grid” which is the future of large-scale energy management. The system presented in this paper has been developed on a self-sufficient solar house called “MagicBox” equipped with grid connection, PV generation, lead-acid batteries, controllable appliances and smart metering. Therefore, there is a large number of energy variables to be monitored that allow us to precisely manage the energy performance of the house by means of collaborative sensors. The experimental results, performed on a real house, demonstrate the feasibility of the proposed collaborative system to reduce the consumption of electrical power and to increase energy efficiency. Full article
(This article belongs to the Special Issue Collaborative Sensors)
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3482 KiB  
Article
An Integrated Testbed for Cooperative Perception with Heterogeneous Mobile and Static Sensors
by Adrián Jiménez-González, José Ramiro Martínez-de Dios and Aníbal Ollero
Sensors 2011, 11(12), 11516-11543; https://doi.org/10.3390/s111211516 - 9 Dec 2011
Cited by 45 | Viewed by 10380
Abstract
Cooperation among devices with different sensing, computing and communication capabilities provides interesting possibilities in a growing number of problems and applications including domotics (domestic robotics), environmental monitoring or intelligent cities, among others. Despite the increasing interest in academic and industrial communities, experimental tools [...] Read more.
Cooperation among devices with different sensing, computing and communication capabilities provides interesting possibilities in a growing number of problems and applications including domotics (domestic robotics), environmental monitoring or intelligent cities, among others. Despite the increasing interest in academic and industrial communities, experimental tools for evaluation and comparison of cooperative algorithms for such heterogeneous technologies are still very scarce. This paper presents a remote testbed with mobile robots and Wireless Sensor Networks (WSN) equipped with a set of low-cost off-the-shelf sensors, commonly used in cooperative perception research and applications, that present high degree of heterogeneity in their technology, sensed magnitudes, features, output bandwidth, interfaces and power consumption, among others. Its open and modular architecture allows tight integration and interoperability between mobile robots and WSN through a bidirectional protocol that enables full interaction. Moreover, the integration of standard tools and interfaces increases usability, allowing an easy extension to new hardware and software components and the reuse of code. Different levels of decentralization are considered, supporting from totally distributed to centralized approaches. Developed for the EU-funded Cooperating Objects Network of Excellence (CONET) and currently available at the School of Engineering of Seville (Spain), the testbed provides full remote control through the Internet. Numerous experiments have been performed, some of which are described in the paper. Full article
(This article belongs to the Special Issue Collaborative Sensors)
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Article
Contrastive Analysis of the Raman Spectra of Polychlorinated Benzene: Hexachlorobenzene and Benzene
by Xian Zhang, Qin Zhou, Yu Huang, Zhengcao Li and Zhengjun Zhang
Sensors 2011, 11(12), 11510-11515; https://doi.org/10.3390/s111211510 - 8 Dec 2011
Cited by 33 | Viewed by 11209
Abstract
Detection of persistent pollutants such as polychlorinated benzene in environment in trace amounts is challenging, but important. It is more difficult to distinguish homologues and isomers of organic pollutantd when present in trace amounts because of their similar physical and chemical properties. In [...] Read more.
Detection of persistent pollutants such as polychlorinated benzene in environment in trace amounts is challenging, but important. It is more difficult to distinguish homologues and isomers of organic pollutantd when present in trace amounts because of their similar physical and chemical properties. In this work we simulate the Raman spectra of hexachlorobenzene and benzene, and figure out the vibration mode of each main peak. The effect on the Raman spectrum of changing substituents from H to Cl is analyzed to reveal the relations between the Raman spectra of homologues and isomers of polychlorinated benzene, which should be helpful for distinguishing one kind of polychlorinated benzene from its homologues and isomers by surface enhanced Raman scattering. Full article
(This article belongs to the Special Issue Sensing of Organic Pollution in Soil, Air, Water and Food)
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1167 KiB  
Article
Design of a Lightweight, Cost Effective Thimble-Like Sensor for Haptic Applications Based on Contact Force Sensors
by Manuel Ferre, Ignacio Galiana and Rafael Aracil
Sensors 2011, 11(12), 11495-11509; https://doi.org/10.3390/s111211495 - 6 Dec 2011
Cited by 13 | Viewed by 10629
Abstract
This paper describes the design and calibration of a thimble that measures the forces applied by a user during manipulation of virtual and real objects. Haptic devices benefit from force measurement capabilities at their end-point. However, the heavy weight and cost of force [...] Read more.
This paper describes the design and calibration of a thimble that measures the forces applied by a user during manipulation of virtual and real objects. Haptic devices benefit from force measurement capabilities at their end-point. However, the heavy weight and cost of force sensors prevent their widespread incorporation in these applications. The design of a lightweight, user-adaptable, and cost-effective thimble with four contact force sensors is described in this paper. The sensors are calibrated before being placed in the thimble to provide normal and tangential forces. Normal forces are exerted directly by the fingertip and thus can be properly measured. Tangential forces are estimated by sensors strategically placed in the thimble sides. Two applications are provided in order to facilitate an evaluation of sensorized thimble performance. These applications focus on: (i) force signal edge detection, which determines task segmentation of virtual object manipulation, and (ii) the development of complex object manipulation models, wherein the mechanical features of a real object are obtained and these features are then reproduced for training by means of virtual object manipulation. Full article
(This article belongs to the Section Physical Sensors)
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1496 KiB  
Article
Development of a 3D Parallel Mechanism Robot Arm with Three Vertical-Axial Pneumatic Actuators Combined with a Stereo Vision System
by Mao-Hsiung Chiang and Hao-Ting Lin
Sensors 2011, 11(12), 11476-11494; https://doi.org/10.3390/s111211476 - 5 Dec 2011
Cited by 21 | Viewed by 10310
Abstract
This study aimed to develop a novel 3D parallel mechanism robot driven by three vertical-axial pneumatic actuators with a stereo vision system for path tracking control. The mechanical system and the control system are the primary novel parts for developing a 3D parallel [...] Read more.
This study aimed to develop a novel 3D parallel mechanism robot driven by three vertical-axial pneumatic actuators with a stereo vision system for path tracking control. The mechanical system and the control system are the primary novel parts for developing a 3D parallel mechanism robot. In the mechanical system, a 3D parallel mechanism robot contains three serial chains, a fixed base, a movable platform and a pneumatic servo system. The parallel mechanism are designed and analyzed first for realizing a 3D motion in the X-Y-Z coordinate system of the robot’s end-effector. The inverse kinematics and the forward kinematics of the parallel mechanism robot are investigated by using the Denavit-Hartenberg notation (D-H notation) coordinate system. The pneumatic actuators in the three vertical motion axes are modeled. In the control system, the Fourier series-based adaptive sliding-mode controller with H tracking performance is used to design the path tracking controllers of the three vertical servo pneumatic actuators for realizing 3D path tracking control of the end-effector. Three optical linear scales are used to measure the position of the three pneumatic actuators. The 3D position of the end-effector is then calculated from the measuring position of the three pneumatic actuators by means of the kinematics. However, the calculated 3D position of the end-effector cannot consider the manufacturing and assembly tolerance of the joints and the parallel mechanism so that errors between the actual position and the calculated 3D position of the end-effector exist. In order to improve this situation, sensor collaboration is developed in this paper. A stereo vision system is used to collaborate with the three position sensors of the pneumatic actuators. The stereo vision system combining two CCD serves to measure the actual 3D position of the end-effector and calibrate the error between the actual and the calculated 3D position of the end-effector. Furthermore, to verify the feasibility of the proposed parallel mechanism robot driven by three vertical pneumatic servo actuators, a full-scale test rig of the proposed parallel mechanism pneumatic robot is set up. Thus, simulations and experiments for different complex 3D motion profiles of the robot end-effector can be successfully achieved. The desired, the actual and the calculated 3D position of the end-effector can be compared in the complex 3D motion control. Full article
(This article belongs to the Special Issue Collaborative Sensors)
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529 KiB  
Article
Ultrasonic Array for Obstacle Detection Based on CDMA with Kasami Codes
by Cristina Diego, Álvaro Hernández, Ana Jiménez, Fernando J. Álvarez, Rebeca Sanz and Joaqúın Aparicio
Sensors 2011, 11(12), 11464-11475; https://doi.org/10.3390/s111211464 - 2 Dec 2011
Cited by 16 | Viewed by 8757
Abstract
This paper raises the design of an ultrasonic array for obstacle detection based on Phased Array (PA) techniques, which steers the acoustic beam through the environment by electronics rather than mechanical means. The transmission of every element in the array has been encoded, [...] Read more.
This paper raises the design of an ultrasonic array for obstacle detection based on Phased Array (PA) techniques, which steers the acoustic beam through the environment by electronics rather than mechanical means. The transmission of every element in the array has been encoded, according to Code Division for Multiple Access (CDMA), which allows multiple beams to be transmitted simultaneously. All these features together enable a parallel scanning system which does not only improve the image rate but also achieves longer inspection distances in comparison with conventional PA techniques. Full article
(This article belongs to the Special Issue Sensorial Systems Applied to Intelligent Spaces)
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2918 KiB  
Article
An Approach to Improve the Quality of Infrared Images of Vein-Patterns
by Chih-Lung Lin
Sensors 2011, 11(12), 11447-11463; https://doi.org/10.3390/s111211447 - 1 Dec 2011
Cited by 13 | Viewed by 7603
Abstract
This study develops an approach to improve the quality of infrared (IR) images of vein-patterns, which usually have noise, low contrast, low brightness and small objects of interest, thus requiring preprocessing to improve their quality. The main characteristics of the proposed approach are [...] Read more.
This study develops an approach to improve the quality of infrared (IR) images of vein-patterns, which usually have noise, low contrast, low brightness and small objects of interest, thus requiring preprocessing to improve their quality. The main characteristics of the proposed approach are that no prior knowledge about the IR image is necessary and no parameters must be preset. Two main goals are sought: impulse noise reduction and adaptive contrast enhancement technologies. In our study, a fast median-based filter (FMBF) is developed as a noise reduction method. It is based on an IR imaging mechanism to detect the noisy pixels and on a modified median-based filter to remove the noisy pixels in IR images. FMBF has the advantage of a low computation load. In addition, FMBF can retain reasonably good edges and texture information when the size of the filter window increases. The most important advantage is that the peak signal-to-noise ratio (PSNR) caused by FMBF is higher than the PSNR caused by the median filter. A hybrid cumulative histogram equalization (HCHE) is proposed for adaptive contrast enhancement. HCHE can automatically generate a hybrid cumulative histogram (HCH) based on two different pieces of information about the image histogram. HCHE can improve the enhancement effect on hot objects rather than background. The experimental results are addressed and demonstrate that the proposed approach is feasible for use as an effective and adaptive process for enhancing the quality of IR vein-pattern images. Full article
(This article belongs to the Special Issue Hand-Based Biometrics Sensors and Systems)
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3082 KiB  
Article
On Mobility Management in Multi-Sink Sensor Networks for Geocasting of Queries
by Ayşegül Tüysüz Erman, Arta Dilo, Lodewijk van Hoesel and Paul Havinga
Sensors 2011, 11(12), 11415-11446; https://doi.org/10.3390/s111211415 - 1 Dec 2011
Cited by 3 | Viewed by 8280
Abstract
In order to efficiently deal with location dependent messages in multi-sink wireless sensor networks (WSNs), it is key that the network informs sinks what geographical area is covered by which sink. The sinks are then able to efficiently route messages which are only [...] Read more.
In order to efficiently deal with location dependent messages in multi-sink wireless sensor networks (WSNs), it is key that the network informs sinks what geographical area is covered by which sink. The sinks are then able to efficiently route messages which are only valid in particular regions of the deployment. In our previous work (see the 5th and 6th cited documents), we proposed a combined coverage area reporting and geographical routing protocol for location dependent messages, for example, queries that are injected by sinks. In this paper, we study the case where we have static sinks and mobile sensor nodes in the network. To provide up-to-date coverage areas to sinks, we focus on handling node mobility in the network. We discuss what is a better method for updating the routing structure (i.e., routing trees and coverage areas) to handle mobility efficiently: periodic global updates initiated from sinks or local updates triggered by mobile sensors. Simulation results show that local updating perform very well in terms of query delivery ratio. Local updating has a better scalability to increasing network size. It is also more energy efficient than ourpreviously proposed approach, where global updating in networks have medium mobility rate and speed. Full article
(This article belongs to the Section Physical Sensors)
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2329 KiB  
Article
Use of Earth’s Magnetic Field for Mitigating Gyroscope Errors Regardless of Magnetic Perturbation
by Muhammad Haris Afzal, Valérie Renaudin and Gérard Lachapelle
Sensors 2011, 11(12), 11390-11414; https://doi.org/10.3390/s111211390 - 30 Nov 2011
Cited by 84 | Viewed by 12805 | Correction
Abstract
Most portable systems like smart-phones are equipped with low cost consumer grade sensors, making them useful as Pedestrian Navigation Systems (PNS). Measurements of these sensors are severely contaminated by errors caused due to instrumentation and environmental issues rendering the unaided navigation solution with [...] Read more.
Most portable systems like smart-phones are equipped with low cost consumer grade sensors, making them useful as Pedestrian Navigation Systems (PNS). Measurements of these sensors are severely contaminated by errors caused due to instrumentation and environmental issues rendering the unaided navigation solution with these sensors of limited use. The overall navigation error budget associated with pedestrian navigation can be categorized into position/displacement errors and attitude/orientation errors. Most of the research is conducted for tackling and reducing the displacement errors, which either utilize Pedestrian Dead Reckoning (PDR) or special constraints like Zero velocity UPdaTes (ZUPT) and Zero Angular Rate Updates (ZARU). This article targets the orientation/attitude errors encountered in pedestrian navigation and develops a novel sensor fusion technique to utilize the Earth’s magnetic field, even perturbed, for attitude and rate gyroscope error estimation in pedestrian navigation environments where it is assumed that Global Navigation Satellite System (GNSS) navigation is denied. As the Earth’s magnetic field undergoes severe degradations in pedestrian navigation environments, a novel Quasi-Static magnetic Field (QSF) based attitude and angular rate error estimation technique is developed to effectively use magnetic measurements in highly perturbed environments. The QSF scheme is then used for generating the desired measurements for the proposed Extended Kalman Filter (EKF) based attitude estimator. Results indicate that the QSF measurements are capable of effectively estimating attitude and gyroscope errors, reducing the overall navigation error budget by over 80% in urban canyon environment. Full article
(This article belongs to the Section Physical Sensors)
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314 KiB  
Article
Improving Social Odometry Robot Networks with Distributed Reputation Systems for Collaborative Purposes
by David Fraga, Álvaro Gutiérrez, Juan Carlos Vallejo, Alexandre Campo and Zorana Bankovic
Sensors 2011, 11(12), 11372-11389; https://doi.org/10.3390/s111211372 - 30 Nov 2011
Cited by 6 | Viewed by 7662
Abstract
The improvement of odometry systems in collaborative robotics remains an important challenge for several applications. Social odometry is a social technique which confers the robots the possibility to learn from the others. This paper analyzes social odometry and proposes and follows a methodology [...] Read more.
The improvement of odometry systems in collaborative robotics remains an important challenge for several applications. Social odometry is a social technique which confers the robots the possibility to learn from the others. This paper analyzes social odometry and proposes and follows a methodology to improve its behavior based on cooperative reputation systems. We also provide a reference implementation that allows us to compare the performance of the proposed solution in highly dynamic environments with the performance of standard social odometry techniques. Simulation results quantitatively show the benefits of this collaborative approach that allows us to achieve better performances than social odometry. Full article
(This article belongs to the Special Issue Collaborative Sensors)
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6283 KiB  
Article
Finger Vein Recognition Using Local Line Binary Pattern
by Bakhtiar Affendi Rosdi, Chai Wuh Shing and Shahrel Azmin Suandi
Sensors 2011, 11(12), 11357-11371; https://doi.org/10.3390/s111211357 - 30 Nov 2011
Cited by 259 | Viewed by 18236
Abstract
In this paper, a personal verification method using finger vein is presented. Finger vein can be considered more secured compared to other hands based biometric traits such as fingerprint and palm print because the features are inside the human body. In the proposed [...] Read more.
In this paper, a personal verification method using finger vein is presented. Finger vein can be considered more secured compared to other hands based biometric traits such as fingerprint and palm print because the features are inside the human body. In the proposed method, a new texture descriptor called local line binary pattern (LLBP) is utilized as feature extraction technique. The neighbourhood shape in LLBP is a straight line, unlike in local binary pattern (LBP) which is a square shape. Experimental results show that the proposed method using LLBP has better performance than the previous methods using LBP and local derivative pattern (LDP). Full article
(This article belongs to the Special Issue Hand-Based Biometrics Sensors and Systems)
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