- 标题
- 摘要
- 关键词
- 实验方案
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Improved triangular-based star pattern recognition algorithm for low-cost star trackers
摘要： Star identification algorithms based on triangular-pattern are more suitable for low-cost star trackers since they require less star density in the field of view to operate effectively. In this paper, we propose a modified star pattern recognition algorithm based on the triangular-based algorithm of “LIEBE”. The main contribution of the proposed work is twofold. First, a new strategy for the selection of star triplets is proposed for database construction. Second, new selection criteria of the reference star are considered for pattern generation process. A sky simulation program is developed to assess mainly the robustness against different conditions of noise. The obtained results show an improvement in the overall identification rate, more robustness towards missing stars, and more efficiency towards magnitude noise. Furthermore, our proposed algorithm shows comparable robustness with the recently proposed triangular algorithms despite their reliance on more accurate camera and a validation process. To assess the algorithm performance, the algorithm is implemented on a prototype of Data Processing Unit (DPU) based on ARM Cortex-M4 processor. In this part, we discuss the major design decisions and we present the hardware architecture of DPU. The algorithm shows promising running time at a reduced on-board database when implemented on ARM platform.
关键词： Small satellite,Star tracker,Hardware implementation,Star pattern recognition,Star database optimization,Star identification
更新于2025-09-19 17:15:36
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Cone Photoreceptor Cell Segmentation and Diameter Measurement on Adaptive Optics Images Using Circularly Constrained Active Contour Model
摘要： PURPOSE. Cone photoreceptor cells can be noninvasively imaged in the living human eye by using nonconfocal adaptive optics scanning ophthalmoscopy split detection. Existing metrics, such as cone density and spacing, are based on simplifying cone photoreceptors to single points. The purposes of this study were to introduce a computer-aided approach for segmentation of cone photoreceptors, to apply this technique to create a normal database of cone diameters, and to demonstrate its use in the context of existing metrics. METHODS. Cone photoreceptor segmentation is achieved through a circularly constrained active contour model (CCACM). Circular templates and image gradients attract active contours toward cone photoreceptor boundaries. Automated segmentation from in vivo human subject data was compared to ground truth established by manual segmentation. Cone diameters computed from curated data (automated segmentation followed by manual removal of errors) were compared with histology and published data. RESULTS. Overall, there was good agreement between automated and manual segmentations and between diameter measurements (n ? 5191 cones) and published histologic data across retinal eccentricities ranging from 1.35 to 6.35 mm (temporal). Interestingly, cone diameter was correlated to both cone density and cone spacing (negatively and positively, respectively; P < 0.01 for both). Application of the proposed automated segmentation to images from a patient with late-onset retinal degeneration revealed the presence of enlarged cones above individual reticular pseudodrusen (average 23.0% increase, P < 0.05). CONCLUSIONS. CCACM can accurately segment cone photoreceptors on split detection images across a range of eccentricities. Metrics derived from this automated segmentation of adaptive optics retinal images can provide new insights into retinal diseases.
关键词： nonconfocal split detection,reticular pseudodrusen,normal database,active contour model,cell segmentation
更新于2025-09-19 17:15:36
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Analysis for an Improved Nanomechanical Microcantilever Sensor on Optical Waveguides
摘要： We announce a new video quality model (VQM) that accounts for the perceptual impact of variable frame delays (VFD) in videos with demonstrated top performance on the laboratory for image and video engineering (LIVE) mobile video quality assessment (VQA) database. This model, called VQM_VFD, uses perceptual features extracted from spatial-temporal blocks spanning fixed angular extents and a long edge detection filter. VQM_VFD predicts video quality by measuring multiple frame delays using perception based parameters to track subjective quality over time. In the performance analysis of VQM_VFD, we evaluated its efficacy at predicting human opinions of visual quality. A detailed correlation analysis and statistical hypothesis testing show that VQM_VFD accurately predicts human subjective judgments and substantially outperforms top-performing image quality assessment and VQA models previously tested on the LIVE mobile VQA database. VQM_VFD achieved the best performance on the mobile and tablet studies of the LIVE mobile VQA database for simulated compression, wireless packet-loss, and rate adaptation, but not for temporal dynamics. These results validate the new model and warrant a hard release of the VQM_VFD algorithm. It is freely available for any purpose, commercial, or noncommercial at http://www.its.bldrdoc.gov/vqm/.
关键词： Edge detection,video quality model,video quality assessment,video quality database,variable frame delay,VQM_VFD
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE Conference on Power Electronics and Renewable Energy (CPERE) - Aswan City, Egypt (2019.10.23-2019.10.25)] 2019 IEEE Conference on Power Electronics and Renewable Energy (CPERE) - Fault Detection and Diagnosis for Photovoltaic Array Under Grid Connected Using Support Vector Machine
摘要： This paper investigates the problem of database-assisted spectrum access in dynamic TV white spectrum networks, in which the active user set is varying. Since there is no central controller and information exchange, it encounters dynamic and incomplete information constraints. To solve this challenge, we formulate a state-based spectrum access game and a robust spectrum access game. It is proved that the two games are ordinal potential games with the (expected) aggregate weighted interference serving as the potential functions. A distributed learning algorithm is proposed to achieve the pure strategy Nash equilibrium (NE) of the games. It is shown that the best NE is almost the same with the optimal solution and the achievable throughput of the proposed learning algorithm is very close to the optimal one, which validates the effectiveness of the proposed game-theoretic solution.
关键词： TV white spectrum,ordinal potential game,geo-location database,learning automata
更新于2025-09-19 17:13:59
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[IEEE IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium - Yokohama, Japan (2019.7.28-2019.8.2)] IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium - Web Camera Sensor Coupled with Lidar Data Flood Map for Flood Warning System
摘要： In this research, a Flood Warning System is designed based on Water Level Data image obtained by a simple web camera. The system processes the output data from the water level image into tables and then connect to the flood map database to select the corresponding map to be displayed as a flood prediction image with a GIS program. The system processes the data in real time to provide public users with an accurate flood area prediction. By using this system, user can expect the area which will be affected when the water level rises to allow peoples that live near the affected area to evacuate or at least to prepare for the upcoming flood. This kind of early warning system is expected not only will save the lives of people who live near the affected area but also save their valuables from the flood disaster. The flood area is segmented from LiDAR data at 1 m intervals and the water level is recorded at 10 cm intervals. The resulting area obtained from elevation data is considered as the boundary of the maximum extent of the flood. Each corresponding map layer is linked to specific water level recorded by the camera.
关键词： web camera,flood warning,flood sensor,remote sensing,database
更新于2025-09-16 10:30:52
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - An Optimized Broadband Waveguide Magic-T for X-band Applications
摘要： Television white space (TVWS) technology is approaching the potential roll-out phase for commercial deployment, supported by recent pilot projects being conducted globally. Undeniably, TVWS technology is faced with daunting challenges that require attention. To enable an ecosystem in which TVWS technology can flourish, there is a need for a complete analysis of the challenges, trends and future research direction related to this technology. Database-assisted TVWS technology is market driven, geared toward the spectrum reuse paradigm, and faces fewer technical hurdles. Our goal in this paper is to present a tutorial review of the challenges related to database-assisted TVWS networks using the SLEPT (social, legal, economic, political, and technological) analysis framework. The SLEPT framework is a management model that is extensively used for quantitative analysis. A brief review of TVWS technology using the SLEPT model reveals that the technology has been socially accepted, legal challenges are evident in some countries, economic models are the way forward and are main focus of current research trends, TVWS technology cannot be implemented without political will emanating from spectrum reforms, and there are many coexistence-motivated technological issues confronting TVWS technology. In summary, this paper provides an up-to-date survey on TVWS and presents current trends and future research directions in the TVWS context.
关键词： self-coexistence,auction,geolocation database,TVWS,SLEPT
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Computing, Electronics & Communications Engineering (iCCECE) - London, United Kingdom (2019.8.22-2019.8.23)] 2019 International Conference on Computing, Electronics & Communications Engineering (iCCECE) - Detailed Analysis of IRIS Recognition Performance
摘要： Iris recognition is a well-known biometric identification system which distinguishes authentic and imposter individuals based on the features of their irides. It employs stringent statistical analyses of the features of irides due to the fact that each person has a unique iris, just like a fingerprint. In this work, the approach adopted towards the iris recognition problem is through an exhaustive and careful analysis of the statistical properties of the iris images and the randomness of spurious noise effects. The ability to differentiate two different templates from each other improves with the increase in the number of the degrees of freedom (DOF). The DOF depends on the encoding schemes utilized and moreover, it is hypothesized that the encoding schemes used in themselves could influence the recognition performance. The CASIA (Chinese Academy of Sciences Institute of Automation) version 1 database of iris images used in this study has been modified by the addition of artificial noise in order to simulate practical real life in situ noisy iris capture environments. The classical and state-of-the-art segmentation techniques have been compared, determining whether they are superior to the others under several conditions. The 1D, 2D Gabor filters and the short window implementation were all tested. The conclusion was that the 2D Gabor Filters produce a lower equal error rate (EER), higher accuracy and decidability than by using the one-dimensional log Gabor filter. After modifying the one-dimensional log Gabor filters, a lower EER and higher accuracy was found as the noise level increased. This makes the modified 1D log Gabor Filters a better proposition in noisy conditions. The generated iris templates have a predetermined theoretical value of DOF and from the statistical analysis, an experimental value can be determined. The relation between these values can be used as a metric to compare different databases.
关键词： CASIA iris image database,decidability,equal error rate,degrees of freedom,recognition,accuracy,iris encoding,low-resolution images,CASIA-iris segmentation
更新于2025-09-16 10:30:52
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[IEEE 2019 XIth International Scientific and Practical Conference on Electronics and Information Technologies (ELIT) - Lviv, Ukraine (2019.9.16-2019.9.18)] 2019 XIth International Scientific and Practical Conference on Electronics and Information Technologies (ELIT) - Computational-Measurement System a??Nanoplasmonicsa??. Part 2: Structure of Microservices
摘要： Ray tracing simulation results indicate that a high-resolution database is not needed to exploit user position knowledge in the 28-GHz band, even in the case of inexact information. A proposed antenna alignment algorithm (using maximum position errors and database resolutions of 10 and 4 m, respectively) that takes advantage of the propagation characteristics knowledge of database points located around the reported location is applied. The results show that the distance between the points can be increased up to 2 m with no considerable negative impact on performance. Simulations also indicate that this outcome is sustained when the maximum power level received at the user equipment varies. The algorithm provides the benefit of a higher initial power delivery and fewer steps, as long as the exact geographical position of the user is within the circular area containing the considered database points. The performance is similar to or better than that of a modified classical hierarchical procedure.
关键词： Base station (BS),database (DB),non-line of sight (NLOS),millimeter wave (mmW),ray tracing (RT),user equipment (UE),signal-to-noise ratio (SNR)
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Dual-Comb Spectroscopy of Acetylene with a Single, Free-Running MIXSEL Generating two Frequency Combs
摘要： Dual-comb spectroscopy combines the advantages of conventional Fourier transform infrared spectroscopy (FTIR) with the measurement speed, stability and accuracy of multiheterodyne beat note detection. Two optical frequency combs (OFCs) with slightly different line spacing beat on a photodetector and convert the optical spectra down to the more accessible radio frequency (RF) domain. This enables an accurate broadband spectrometer without moving parts featuring short measurement time, however, it also requires two mutually locked OFCs with good noise performance which is challenging. Dual-comb modelocked optically pumped semiconductor disk lasers (SDLs) provide a great simplification. The modelocked integrated external-cavity surface emitting laser (MIXSEL) is a special type of ultrafast SDLs which integrates a semiconductor gain and a saturable absorber in a single epitaxial structure and allows for modelocking in a simple and straight cavity. Most recently we increased the modelocked optical bandwidth above 10 nm with pulse durations below 150 fs. With two intracavity birefringent crystals, the initially unpolarized beam is separated onto two spots on the MIXSEL chip, which can be individually pumped. The dual-comb MIXSEL is a straight linear cavity formed by the two end mirrors (i.e. MIXSEL chip and output coupler (OC) and emits two orthogonally polarized OFCs with a slight difference in line spacing from the same cavity with an intrinsically high mutual coherence. Here, we present dual-comb spectroscopy of acetylene with a single, free-running dual-comb MIXSEL at 1030 nm (290 THz). The laser provides more than 10 nm of optical bandwidth usable for spectroscopic interrogations and with a resolution of 2.73 GHz, we can clearly resolve the individual absorption lines with great precision. Without active stabilization and locking electronics, the overlay of the experimentally acquired dual-comb transmission follows line-by-line the characteristic acetylene transmission envelope as computed from the HITRAN 2016 database after an a posteriori wavelength calibration. Furthermore, the residuals between the observed traces and the HITRAN reference spectrum and its standard deviation of 0.028 attests good transmission intensity precision to our dual-comb spectrometer.
关键词： optical frequency combs,MIXSEL,acetylene,Dual-comb spectroscopy,HITRAN database
更新于2025-09-12 10:27:22
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[IEEE 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - Sarajevo, Bosnia and Herzegovina (2019.9.2-2019.9.4)] 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - GPON Frame Data Processing
摘要： This article presents a method for data analysis of GPON frames transmitted over passive optical networks using the gigabit encapsulation method. First, the introduction is described. The following sections are focused on individual parts of our designed system, including capturing frames, storing frames, analysis and interpretation of results.
关键词： Python,data processing,GPON,database
更新于2025-09-12 10:27:22