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- 摘要
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- 实验方案
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Spatial Interpolation Enables Normative Data Comparison in Gaze-Contingent Microperimetry
摘要： PURPOSE. To demonstrate methods that enable visual field sensitivities to be compared with normative data without restriction to a fixed test pattern. METHODS. Healthy participants (n ? 60, age 19–50) undertook microperimetry (MAIA-2) using 237 spatially dense locations up to 138 eccentricity. Surfaces were fit to the mean, variance, and 5th percentile sensitivities. Goodness-of-fit was assessed by refitting the surfaces 1000 times to the dataset and comparing estimated and measured sensitivities at 50 randomly excluded locations. A leave-one-out method was used to compare individual data with the 5th percentile surface. We also considered cases with unknown fovea location by adding error sampled from the distribution of relative fovea–optic disc positions to the test locations and comparing shifted data to the fixed surface. RESULTS. Root mean square (RMS) difference between estimated and measured sensitivities were less than 0.5 dB and less than 1.0 dB for the mean and 5th percentile surfaces, respectively. Root mean square differences were greater for the variance surface, median 1.4 dB, range 0.8 to 2.7 dB. Across all participants 3.9% (interquartile range, 1.8–8.9%) of sensitivities fell beneath the 5th percentile surface, close to the expected 5%. Positional error added to the test grid altered the number of locations falling beneath the 5th percentile surface by less than 1.3% in 95% of participants. CONCLUSIONS. Spatial interpolation of normative data enables comparison of sensitivity measurements from varied visual field locations. Conventional indices and probability maps familiar from standard automated perimetry can be produced. These methods may enhance the clinical use of microperimetry, especially in cases of nonfoveal fixation.
关键词： fundus perimetry,microperimetry,normative database,AMD,gaze-contingent
更新于2025-09-23 15:23:52
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Real time video image enhancement approach using particle swarm optimisation technique with adaptive cumulative distribution function based histogram equalization
摘要： Recent years, real time videos are playing an important role in different applications such as pattern recognition, security purpose, news analysis, weather digest, and video browser and so on. Due to the importance of real time video applications, the quality of the real time video must be improved for making effective results in real time video analysis process. This paper introduces the particle optimization with adaptive cumulative distribution based histogram enhancement technique (PACDHE) for improving the real time video quality. Initially the videos are collected, each incoming frame has been analyzed and noise present in the video frame is eliminated by applying the non-divisional median filter. After that, quality of real time video is enhanced iteratively by examining each pixel present in video frames using the optimized fitness and cumulative distribution function. This process is repeated continuously until to enhance the real time video frames contrast and quality. Then the performance of the system is analyzed by using CV online video database and the efficiency is examined in terms of peak signal to noise ratio (PSNR), Absolute Mean Brightness Error (AMBE) and Entropy. The experimental results of PSO are compared with genetic algorithm based approach and found that PSO outperforms the GA approach and the existing histogram equalization approach and the existing histogram equalization approaches.
关键词： contrast enhancement,particle optimization based adaptive cumulative distribution based histogram enhancement technique (PACDHE),fitness and cumulative distribution function,CV online video database,Video quality
更新于2025-09-23 15:23:52
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[IEEE 2018 26th European Signal Processing Conference (EUSIPCO) - Rome (2018.9.3-2018.9.7)] 2018 26th European Signal Processing Conference (EUSIPCO) - Ear Presentation Attack Detection: Benchmarking Study with First Lenslet Light Field Database
摘要： Ear recognition has received broad attention from the biometric community and its emerging usage in multiple applications is raising new security concerns, with robustness against presentation attacks being a very active field of research. This paper addresses for the first time the ear presentation attack detection problem by developing an exhaustive benchmarking study on the performance of state-of-the-art light field and non-light field based ear presentation attack detection solutions. In this context, this paper also proposes an appropriate ear artefact database captured with a Lytro ILLUM lenslet light field camera, including both 2D and light field contents, using several types of presentation attack instruments, including laptop, tablet and two different mobile phones. Results show very promising performance for two recent light field based presentation attack detection solutions originally proposed for face presentation attack detection.
关键词： Ear Presentation Attack Detection,Feature Extraction,Light Field Imaging,Artefact Database
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference of the Biometrics Special Interest Group (BIOSIG) - Darmstadt (2018.9.26-2018.9.28)] 2018 International Conference of the Biometrics Special Interest Group (BIOSIG) - A benchmark database of visible and thermal paired face images across multiple variations
摘要： Although visible face recognition systems have grown as a major area of research, they are still facing serious challenges when operating in uncontrolled environments. In attempt to overcome these limitations, thermal imagery has been investigated as a promising direction to extend face recognition technology. However, the reduced number of databases acquired in thermal spectrum limits its exploration. In this paper, we introduce a database of face images acquired simultaneously in visible and thermal spectra under various variations: illumination, expression, pose and occlusion. Then, we present a comparative study of face recognition performances on both modalities against each variation and the impact of bimodal fusion. We prove that thermal spectrum rivals with the visible spectrum not only in the presence of illumination changes, but also in case of expression and poses changes.
关键词： visible spectrum,thermal spectrum,pose,score-level fusion,sensor-level fusion,occlusion,expression,illumination,face database
更新于2025-09-23 15:22:29
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[Lecture Notes in Computer Science] Combinatorial Image Analysis Volume 11255 (19th International Workshop, IWCIA 2018, Porto, Portugal, November 22–24, 2018, Proceedings) || Image-Based Object Spoofing Detection
摘要： Using 2D images in authentication systems raises the question of spoof attacks: is it possible to deceive an authentication system using fake models possessing identical visual properties of the genuine one? In this work, an anti-spoofing method approach for a wine anti-counterfeiting system is presented. The proposed method relies in two different color spaces: CIE L*u*v* and Y CrCb, to distinguish between a genuine instance and a spoof attack. To evaluate the proposed strategy, two databases were used: a private database, with photos/2D attacks of cork stoppers, created for this work; and the public Replay-Attack database that is used for face spoofing detection methods testing. The results on the private database show that the anti-spoofing approach is able to distinguish with high accuracy a real photo from an attack. Regarding the public database, the results were obtained with existing methods, as the best HTER results using a single frame approach.
关键词： Spoofing detection,Object spoofing detection,Cork-Print-Attack Database,Replay-attack database,Face spoofing detection
更新于2025-09-23 15:21:21
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[IEEE 2018 9th International Conference on Computing, Communication and Networking Technologies (ICCCNT) - Bangalore (2018.7.10-2018.7.12)] 2018 9th International Conference on Computing, Communication and Networking Technologies (ICCCNT) - A Perceptual Field of Vision, Using Image Processing
摘要： Currently, estimated facts state that there are more than 285 million visually impaired people around the globe, of which 39 million are blind and the others have a low vision [1]. Approximately 90% of people suffering from blindness are from low-income backgrounds [2]. The main aim of this paper is to provide an efficient visual platform to enhance the perception of the surroundings for a visually impaired user. This is achieved by using the concept of real-time image and video processing. This data is analyzed and compared along with the database which consists of pre-stored data that aids in recognition of the captured image. A head mount camera is used to capture an image on a real-time basis whenever desired. The camera is placed to provide a maximum field of vision and to eliminate the blind spot. The captured image is then processed and compared with the information stored in the database, providing an audio output indicating the desired information. Audio output is provided through bone conduction headphones which communicate audio signals directly with the inner ear. This keeps the outer ear free to be sensitive to the surroundings. A distress alert mechanism is also included as a safety measure to the blind at times of danger. It helps in sending messages containing distress alert signal which contains current location of the user.
关键词： virtual vision,computer vision,audio processing,distress alert,bone conduction,image processing,database
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Datacubes: A Technology Survey
摘要： Datacubes are emerging as a paradigm which allows offering massive spatio-temporal data more in a more homogenized and better to analyze fashion, in particular when it comes to mixed spatial and temporal evaluation. While this is agreed by many, there is no broad consensus yet on access APIs and paradigms, such as query languages versus procedural inter-faces. Further, questions of efficient storage organization and processing of the underlying multi-dimensional arrays arise. In our contribution we provide a technology overview on datacube approaches, involving Array Databases, systems with procedural (typically python) interfaces, array libraries, and more.
关键词： Datacube,Array Database,Analysis Ready Data,Survey
更新于2025-09-23 15:21:21
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Study on the intelligent model database modeling the laser welding for aerospace aluminum alloy
摘要： With the purpose of improving the modeling e?ciency, the model database is established targeting that in-telligent modeling of laser welding for aerospace aluminum alloy. The model database consists of material database, heat source model database and weld joint structure database. The aerospace aluminum alloys are classi?ed reasonably in order to establish the material model database which can manage the thermo-physical properties of aluminum alloys. The heat source models of laser welding are summarized to establish model database on the basis of the di?erent energy distribution characteristics. The joint structure database includes butt joint, T-joint and lap joint. Modeling of arbitrary structures can be implemented quickly and e?ciently when modelers invoke and assemble this model database. The ?nite element model is e?ciently established and accurately solved by taking the 5A90 and 2219 aluminum alloy laser welding as an example. Finally, it is found that the model database established in this paper can greatly improve the modeling e?ciency of laser welding numerical simulation.
关键词： Laser welding,Model database,Aluminum alloy,Structural model,Heat source model,Material model
更新于2025-09-23 15:21:01
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The influence of the solar radiation database and the photovoltaic simulator on the sizing and economics of photovoltaic-diesel generators
摘要： This study evaluated the outcome differences when adopting five different solar irradiation databases on the sizing of hybrid solar photovoltaic-diesel generators designed to supply electricity to isolated minigrids. To do this, the two most widely adopted photovoltaic (PV) simulation packages in the market, namely PVsyst? and HOMER Energy? were used. The different origins, data timespan, space and time resolution, of the five most relevant solar irradiation databases available for the region were compared. A case study was presented to illustrate the influences of the solar irradiation database and the solar simulation tool on the resulting PV generator. Furthermore, the hourly behavior of the energy supply to an existing load in a minigrid in the Brazilian Amazon was evaluated, together with the savings in diesel obtained with the resulting PV generator. Evaluating the five options of solar radiation databases, for the same PV plant configuration, variations of up to 19.7% were found in the expectation of PV generation. When the simulation software package was varied, the combined effect (radiation database X PV system sizing tool) showed differences of up to 20.6%. This demonstrates that despite having different algorithms, computational tools have a small influence (less than 1%) on results. These combined differences, taking into account the load curve behavior and the total diesel generation capacity installed at the site, resulted in over 100% differences in the optimum PV generator size in the case study. The total savings in diesel fuel, over a 15-years period, ranged from $ 6.5 million to over $ 16 million (> 2.5 times) for the smallest PV system. This demonstrates the importance of the correct choice of database. These evaluations can be extended to minigrids of any size elsewhere. The novelty and originality of this study is to demonstrate and quantify for the first time the influence of the solar radiation database and the PV simulator package on the sizing of PV-diesel generators. The consequences of this study are not only of scientific and academic importance, but of economic and commercial interest as well.
关键词： Photovoltaic simulation tool,Hybrid photovoltaic-diesel power plant,Solar database,Minigrids,Solar irradiation
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Modelling, Simulation, and Performance Analysis of a Microgrid with Photovoltaic Energy for Eastern Region of Saudi Arabia
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,VQM_VFD,video quality model,video quality database,variable frame delay,video quality assessment
更新于2025-09-23 15:19:57