Precise Sensor Research Articles

AUTOMATED MOSAICKING OF GEOSTATIONARY OCEAN COLOR IMAGER BY COMBINATION OF SPATIAL AND FREQUENCY MATCHING

Abstract. In general, image mosaicking is a useful and important processing for handling images with narrow field of view. It is being used widely for images from commercial cameras as well as from aerial and satellite cameras. For mosaicking images with geometric distortion, geometric correction of each image should be performed before combining images. However, automated mosaicking images with geometric distortion is not a trivial task. The goal of this paper is the development of automated mosaicking techniques applicable to handle GOCI images. In this paper, we try to extract tie-points by using spatial domain and frequency domain matching and perform the mosaicking of GOCI. The method includes five steps. First, we classify GOCI image slots according to the existence of shorelines by spatial domain matching. Second, we perform precise geometric correction on the slots with shorelines. Third, we perform initial sensor modelling for the slots without shorelines and apply geometric correction based on the initial model. Fourth, the relative relationship between the slots without shorelines and the slots with shorelines is estimated through frequency domain matching. Lastly, mosaicking of geometrically corrected all 16 image slots is performed. The proposed method was verified by applying to real GOCI images. The proposed method was able to perform automated mosaicking even for images without shorelines, and its accuracy and processing time were satisfactory. For future research, we will improve frequency matching to generate multiple tie-points and to analyse the applicability of precise sensor modelling directly from frequency matching. It is expected that the proposed method can be applied to the follow-up sensor of the GOCI, GOCI-II, and other ocean satellite images.

Laplace ℓ1 Huber based cubature Kalman filter for attitude estimation of small satellite

This paper offers a solution to the attitude estimation of small satellite with the existence of model error and heavy-tailed noise, which is referred as to the Laplace ℓ1 Huber Based Kalman filter (ℓ1-HBKF). It employs the Laplace distribution and Huber based method to update the measurement covariance to deal with different types of model error or heavy-tailed noise for robust design. Then, the majorization minimization approach is discussed to improve the estimation accuracy by an iterative algorithm. In addition, the proposed ℓ1-HBKF is implemented in the Kalman filtering framework and is further extended by the strategy of fifth-degree cubature rule for high accuracy. Finally, the attitude estimation of small satellite is simulated and compared with conventional cubature Kalman filter (CKF), which can prove the accuracy and robustness of the proposed methods for the attitude estimation with low precision sensors.

Single mode compound microsphere laser

Single mode laser is demonstrated based on compound microspheres. The two coupled microspheres, corresponding to the diameters of 32.7 μm and 49.2 μm, are both made from Er3+/Yb3+ co-doped phosphate glass. Based on the Vernier effect, single mode laser emission has been realized at 1544.43 nm with the side-mode suppression ratio of 45.1 dB and the threshold of only 163 μW. This compound microspheres scheme can effectively select one laser emission mode among various modes, which can potentially used in micro-size laser source, high precision sensor and other frontier fields.

Irradiation effects on electrical properties of DNA solution/Al Schottky diodes

Deoxyribonucleic acid (DNA) has emerged as one of the most exciting organic material and as such extensively studied as a smart electronic material since the last few decades. DNA molecules have been reported to be utilized in the fabrication of small-scaled sensors and devices. In this current work, the effect of alpha radiation on the electrical properties of an Al/DNA/Al device using DNA solution was studied. It was observed that the carrier transport was governed by electrical interface properties at the Al–DNA interface. Current (I)–voltage (V) curves were analyzed by employing the interface limited Schottky current equations, i.e., conventional and Cheung and Cheung’s models. Schottky parameters such as ideality factor, barrier height and series resistance were also determined. The extracted barrier height of the Schottky contact before and after radiation was calculated as 0.7845, 0.7877, 0.7948 and 0.7874 eV for the non-radiated, 12, 24 and 36 mGy, respectively. Series resistance of the structure was found to decline with the increase in the irradiation, which was due to the increase in the free radical root effects in charge carriers in the DNA solution. Results pertaining to the electronic profiles obtained in this work may provide a better understanding for the development of precise and rapid radiation sensors using DNA solution.

Optical system design of star sensor and stray light analysis

BackgroundStar sensor is one of the precise attitude determination sensors. It is an electro-optical system that takes an image from a set of stars and by comparing it with the star catalogue determines angle deviation of the satellite and modifies its attitude. Star sensor is composed of baffle, optical system, detector, and electronic and image processing system.MethodsIn this article, first subsystems of a star sensor is briefly described, then by determining the optical parameters, an optical system with proper quality is designed, and the tolerances are considered.ResultsThe simulation results and the optical evaluation curves indicate that the image quality is close to the diffraction limit. Next, stray lights from off-axis sources like the sun, are analyzed. For this purpose, the main parameters of baffle designing such as its dimensions and arrangement of the vanes inside it, are determined and then a cylindrical baffle with internal vanes for the star sensor is designed.ConclusionResults show that stray lights reduced 10− 11 times with the presence of baffle and its vanes.

Highly Sensitive Detection of UV Radiation Using a Uranium Coordination Polymer.

The accurate detection of UV radiation is required in a wide range of chemical industries and environmental or biological related applications. Conventional methods taking advantage of semiconductor photodetectors suffer from several drawbacks such as sophisticated synthesis and manufacturing procedure, not being able to measure the accumulated UV dosage as well as high defect density in the material. Searching for new strategies or materials serving as precise UV dosage sensor with extremely low detection limit is still highly desirable. In this work, a radiation resistant uranium coordination polymer [UO2(L)(DMF)] (L = 5-nitroisophthalic acid, DMF = N,N-dimethylformamide, denoted as compound 1) was successfully synthesized through mild solvothermal method and investigated as a unique UV probe with the detection limit of 2.4 × 10-7 J. On the basis of the UV dosage dependent luminescence spectra, EPR analysis, single crystal structure investigation, and the DFT calculation, the UV-induced radical quenching mechanism was confirmed. Importantly, the generated radicals are of significant stability which offers the opportunity for measuring the accumulated UV radiation dosage. Furthermore, the powder material of compound 1 was further upgraded into membrane material without loss in luminescence intensity to investigate the real application potentials. To the best of our knowledge, compound 1 represents the most sensitive coordination polymer based UV dosage probe reported to date.

Single-Atom Transistor as a Precise Magnetic Field Sensor.

Feshbach resonances, which allow for tuning the interactions of ultracold atoms with an external magnetic field, have been widely used to control the properties of quantum gases. We propose a scheme for using scattering resonances as a probe for external fields, showing that by carefully tuning the parameters it is possible to reach a 10^{-5} G (or nT) level of precision with a single pair of atoms. We show that, for our collisional setup, it is possible to saturate the quantum precision bound with a simple measurement protocol.

A closed-loop ΣΔ modulator for micromechanical capacitive sensors

This paper describes a CMOS fully-differential switched-capacitor (SC) single-loop Sigma-Delta (ΣΔ) modulator specialized for highly precise micromechanical capacitive sensors. This design adopts a single-loop, fourth-order, one-bit quantization architecture with feedforward paths for lower nonlinearities and power consumption. Systematic optimization is used to avoid deterioration in conversion accuracy caused by capacitor mismatch. Chopper-stabilization and double-sampling techniques are also employed to enhance performances in noise depression. Manufactured in a standard 0.35 µm CMOS process, the ASIC occupies an area of 5.32 mm2 including 25 pads. This modulator achieves a signal-to-noise ratio (SNR) of 105.2 dB and dynamic range (DR) of 113.7 dB. The whole chip consumes 12.6 mW from a 5 V supply.

Design of a Phase Sensor Applied in the Optical Phase-Locked Loop Based on a High-Speed Coherent Laser Communication System

The background of our research is, designing a precise phase detection sensor for high-speed coherent homodyne systems, and combining it with optical phase-locked loops (OPLLs) to achieve coherent demodulation and carrier recovery. For existing phase sensors, there are problems, such as low phase gain, long dead-time, and difficulty in distinguishing directions. Therefore, we proposed a multilevel-loop compound control phase sensor based on exclusive-OR gates. The sensing system consists of three loops. The tunable range of the temperature loop is 30 GHz. Its tuning rate value is 50 MHz/s. In addition, the inner ring consists of a piezoelectric loop and an acousto-optic frequency shifter loop. According to demand, we established a relevant model, and analyzed and calculated the parameters. The reliability and validity of this sensor are substantiated after setting up the experimental environment. The results show that the lock-in range is 30 GHz, the bandwidth is 1.5 MHz, and the real-time performance of the PLL is improved. In a communication test with a rate of 5 Gbps, the realized bit error ratio is $1.55\times 10-8$ when the optical power of the signal is −40.4 dBm. Therefore, this sensor system improves detection sensitivity. At the end of this paper, we propose some ideas to improve sensitivity, which will be the focus of our next phase.

EMPIRICAL METHODS FOR ESTIMATING REFERENCE SURFACE NET RADIATION FROM SOLAR RADIATION

In agrometeorology, reference surface consists of those traditional grass cover on weather stations. Net radiation (Rn) of this surface is an important information that has many applicability, but its measurement is rare due to the high cost of the sensor and the complexity involved on the measurement. Therefore, estimate Rn from another variable is desirable, as from solar radiation (Rs); however, standard methods used are complex, making interesting the use of simplified methodologies. Considering these aspects, the present study aimed to set two empirical methods to estimate Rn from Rs for Dourados region, located in the Mato Grosso do Sul State, Brazil. One method was set with a scientific purpose (Gauss Method) and it comprised a mathematical modeling. The other one was set with a practical purpose (Practical Method) and comprised the determination of fixed monthly conversion factors. It was used daily Rs data of a 12-years database. With these, there were estimated Rn values by the standard method recommended by FAO. Gauss Method was set using Table Curve 2D 5.01 software. Modeling consisted in defining the values of the equation parameters. On Practical Method we developed monthly coefficients of the ratio Rn/Rs. In order to validate both methods it was measured Rs and Rn during two years using high precision sensors. In addition, Rn values were estimated by both methods and then compared with those measured. Both estimating methods showed satisfactory results, with low error and low advantage for the Gauss Method.

Feasibility Analysis of Precise Sensor Modelling for KOMPSAT-3A Imagery Using Unified Control Points

Feasibility Analysis of Precise Sensor Modelling for KOMPSAT-3A Imagery Using Unified Control Points

High-Precision Mixed-Signal Sensor Interface for a Wide Temperature Range [0–300°C

Sensor interfacing is a crucial component for today's systems in many application domains. Especially in automotive and manufacturing fields, high temperatures are encountered. For extracting the typically small sensor signals, an interface near the sensor is needed to provide high accuracy and robustness. This results in challenges in circuit design and architecture to avoid temperature-related nonideal effects. In this contribution, we present a novel system architecture for a Wheatstone bridge interfacing system. By encoding the sensor signal in time domain and augmenting the system with additional observations, we present a robust and precise sensor interface operating at up to 300°C without breaking accuracy or functional requirements because of high-temperature effects. We present a realization of this concept proven to be accurate within ±1.3% full scale over the full temperature range.

Sensor Fusion for Tour-Guide Robot Localization

Doris, the social robot girl, is under development to be employed in museums and trade fairs as a tour guide. External sensorial information must be inputted so that Doris moves around each new location by using landmark identification points that can improve the real localization of the robot in combination with an extended Kalman filter. Doris is equipped with a semantic map that contains several information points such as the building structure, sites that the robot must pass, features (obstacles) of the built environment, and landmark locations. Three additional sensors were installed on Doris: a laser range finder LMS-200, an omnidirectional Mobotix C25 camera, and an RFID system Speedway Revolution 220 by Impinj. The use of these sensors implies the use of different types of landmarks: 35-cm-high circular landmarks, placed on the ground and covered with a reflective laser-detectable material; markers similar to QR codes placed at 250 cm above the ground level that the omnidirectional camera can identify; and RFID detectable dogbone antennas. One contribution is to prove a simple methodology of localization by using sensor fusion with a semantic map, without mapping the whole environment by creating a point cloud map and without using the SLAM technique. Additionally, another contribution for the research is to define a good methodology for a precise sensors calibration. The initial results showed that each sensor functions efficiently, when using only the laser and the camera, due to the low accuracy of the RFID system alone. The final results show the behavior of the robot localization in the presence of people and different objects when both sensors are working at the same time. Occlusions may affect the reflective landmarks or visual markers. Therefore, the sensor fusion is implemented to achieve better robustness in the location estimation.

Environment dependent enhanced photoluminescence and Boolean logic gates like behavior of Bi2O3 and Ag:Bi2O3 nanostructures

In the evolution of nanotechnology research for smart and precise sensor fabrication, here we report the implementation of simple logic gate operations performing by luminescent nanostructures in biomolecule environment based on photoluminescence (PL) technique. This present work deals with the luminescence property of α-Bi2O3 and Ag modified α-Bi2O3 nanostructures for d-glucose and Bovine serum albumin (BSA) sensing applications. These nanostructures are prepared by simple co-precipitation method and their morphology are examined using transmission electron microscope (TEM). We explore the PL characteristics of the prepared nanostructures and observe their change in PL intensity in the presence of d-glucose and BSA molecules. Enhancement in PL intensity is observed in the presence of d-glucose and BSA. Based on the PL response of prepared nanostructures in the biomolecule environment, we demonstrate biophotonic logic gates including YES, PASS 0, OR and INHIBIT gates.

Enhanced sensing performance of bimetallic Al/Ag-CNF network and porous PDMS-based triboelectric acetylene gas sensors in a high humidity atmosphere

We report a self-powered active gas sensor that can detect acetylene (C2H2) reliably and accurately by measuring the output voltages generated during contact electrification between bimetallic Al/Ag-carbon nanofiber (CNF) network and porous PDMS friction surfaces. Upon exposure to certain concentrations of C2H2, the triboelectric charging behavior of the sensor is altered due to a surface reaction between C2H2 molecules and the Al/Ag-CNF friction layer. The sensor exhibits excellent sensitivity of 83% and a quick response time of 88 s to C2H2 gas at a concentration of 1000 ppm. Importantly, the friction surfaces exhibit high hydrophobicity, which preferentially minimizes the influence of humidity and provides superior sensing performance even in a high humidity atmosphere (∼87% relative humidity). We believe that the proposed approach for harvesting energy and sensing can be advantageous in practical applications and will stimulate new research for the development of high performance, precise, reliable, and durable self-powered active gas sensors that can operate in hostile environments.

Thermal actuation performance modification of coiled artificial muscle by controlling annealing stress

ABSTRACTTwisted and coiled polymer (TCP) is a promising linear artificial muscle fabricated from nylon or other polymeric fibers, whose geometric structure is similar to a coil spring. TCP muscle is actuated reversibly with negative coefficients of thermal expansion. Twisting, coiling, and annealing are the main fabricating procedures. Annealing is the key process to form TCP muscles with stable performance. To modify and enhance actuation performance, it is necessary to explore and reveal influences of annealing process on thermal actuation (contraction strain, nominal modulus, and geometrical characteristic). Therefore, a new TCP fabrication and test platform is first established, which can quantize key geometrical and force parameters by multiple precise sensors. Then, four types of TCP muscles using nylon 6 fibers with varied diameters are fabricated and annealed under different conditions. As one of the important factors in annealing process, the nominal tensile stress is adjusted and controlled. Meanwhile, the contraction strain and nominal modulus are tested compared with the general annealing method. Finally, the experiment results show that contraction strain can be enhanced about two times (nominal modulus decreases accordingly) by increasing annealing stress, and the actuation performance can be remodeled reversibly by adjusting annealing stress and annealing repetitively. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 383–390

Single-polarization operation in suspended-core microstructured fibers

We present the design and investigation of a single-polarization suspended-core fiber with an elliptical core consisting of crossed rectangular-shaped dielectric strips. By optimizing the fiber configuration parameters, single-polarization single-mode transmission with a bandwidth of 400nm can be obtained. Also, the power fraction in air of the x-polarization fundamental mode is relatively high, which facilitates its applications in high precision sensors.

A PVC/polypyrrole sensor designed for beef taste detection using electrochemical methods and sensory evaluation

An electrochemical sensor for detection of beef taste was designed in this study. This sensor was based on the structure of polyvinyl chloride/polypyrrole (PVC/PPy), which was polymerized onto the surface of a platinum (Pt) electrode to form a Pt-PPy-PVC film. Detecting by electrochemical methods, the sensor was well characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The sensor was applied to detect 10 rib-eye beef samples and the accuracy of the new sensor was validated by sensory evaluation and ion sensor detection. Several cluster analysis methods were used in the study to distinguish the beef samples. According to the obtained results, the designed sensor showed a high degree of association of electrochemical detection and sensory evaluation, which proved a fast and precise sensor for beef taste detection.

A facile, precise radial artery pulse sensor based on stretchable graphene-coated fiber

We design and fabricate a facile, portable and scalable radial artery pulse sensor, then successfully employ it into the analysis of personalized health status. The sensing component comes from a stretchable graphene-coated fiber which shows good linearity and sensitivity to the tensile strain. Further combined with the smart structure of the sensor, the precise detection of periodic pulse wave and the wave changes induced by exercise and disease becomes avaiable and repeatable. In particular, the obtained single waveform contains almost all the characteristics the medical analysis requires, from which we can evaluate the cardiovascular risk factors for citizen medicine, home healthcare and disease prevention.

A comparative study of different equivalent circuit models for estimating state-of-charge of lithium-ion batteries

An appropriate model is a prerequisite for accurate state-of-charge (SOC) estimation. The widely used equivalent circuit models (ECMs) employ a variety of forms; thus, to find the optimum ECM is a primary task for SOC estimation. In this work, we examined eleven ECMs to fulfill the following goals: (1) to compare the typical ECMs for accuracy, stability, and robustness of model and SOC estimation; (2) to compare and evaluate the robustness of the ECMs considering model and sensor errors. The results indicate that the model accuracy does not always improve by increasing the order of the RC network. Conversely, over-fitting problems appear with a certain probability. The first- and second-order RC models are the best choice owing to their balance of accuracy and reliability for LiNMC batteries. The higher-order RC model has better robustness considering the variation in model parameters and sensor errors. Independently of the ECM adopted, an accurate OCV-SOC curve and high precision sensors are essential.