spike detection

尖峰检测
  • 文章类型: Journal Article
    通过神经元的电生理表型表征神经元对于理解行为和认知功能的神经基础至关重要。技术发展使得能够收集数百个神经记录;这需要能够有效地执行特征提取的新工具。为了解决迫切需要一个强大和可访问的工具,我们开发了ElecFeX,一个基于MATLAB的开源工具箱,(1)具有直观的图形用户界面,(2)提供可定制的测量范围广泛的电生理特征,(3)通过批量分析毫不费力地处理大型数据集,和(4)产生格式化的输出以供进一步分析。我们在一组不同的神经记录上实现了ElecFeX;展示了它的功能,多功能性,以及捕获电特征的效率;并确立了其在区分跨大脑区域和物种的神经元亚群中的意义。因此,ElecFeX被呈现为用户友好的工具箱,通过最大限度地减少从其电生理数据集中提取特征所需的时间来使神经科学社区受益。
    Characterizing neurons by their electrophysiological phenotypes is essential for understanding the neural basis of behavioral and cognitive functions. Technological developments have enabled the collection of hundreds of neural recordings; this calls for new tools capable of performing feature extraction efficiently. To address the urgent need for a powerful and accessible tool, we developed ElecFeX, an open-source MATLAB-based toolbox that (1) has an intuitive graphical user interface, (2) provides customizable measurements for a wide range of electrophysiological features, (3) processes large-size datasets effortlessly via batch analysis, and (4) yields formatted output for further analysis. We implemented ElecFeX on a diverse set of neural recordings; demonstrated its functionality, versatility, and efficiency in capturing electrical features; and established its significance in distinguishing neuronal subgroups across brain regions and species. ElecFeX is thus presented as a user-friendly toolbox to benefit the neuroscience community by minimizing the time required for extracting features from their electrophysiological datasets.
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  • 文章类型: Journal Article
    患有良性儿童癫痫伴中央颞部尖峰(BECT)的儿童有尖峰,夏普,和他们的脑电图(EEG)上的复合波。有必要检测尖峰以临床诊断BECT。模板匹配方法可以有效地识别尖峰。然而,由于个体的特异性,在实际应用中找到有代表性的模板来检测尖峰通常是具有挑战性的。
    本文提出了一种基于锁相值(FBN-PLV)和深度学习的使用功能脑网络的尖峰检测方法。
    要获得高检测效果,该方法使用特定的模板匹配方法和蒙太奇的“峰峰现象”来获得一组候选尖峰。有了一组候选尖峰,基于相位锁定值(PLV)构建功能脑网络(FBN),以提取具有相位同步的尖峰放电过程中的网络结构特征。最后,将候选尖峰的时域特征和FBN-PLV的结构特征输入到人工神经网络(ANN)中以识别尖峰。
    基于FBN-PLV和ANN,儿童医院4例BECT病例的脑电图数据集,浙江大学医学院的AC检测为97.6%,SE为98.3%,SP96.8%。
    UNASSIGNED: Children with benign childhood epilepsy with centro-temporal spikes (BECT) have spikes, sharps, and composite waves on their electroencephalogram (EEG). It is necessary to detect spikes to diagnose BECT clinically. The template matching method can identify spikes effectively. However, due to the individual specificity, finding representative templates to detect spikes in actual applications is often challenging.
    UNASSIGNED: This paper proposes a spike detection method using functional brain networks based on phase locking value (FBN-PLV) and deep learning.
    UNASSIGNED: To obtain high detection effect, this method uses a specific template matching method and the \'peak-to-peak\' phenomenon of montages to obtain a set of candidate spikes. With the set of candidate spikes, functional brain networks (FBN) are constructed based on phase locking value (PLV) to extract the features of the network structure during spike discharge with phase synchronization. Finally, the time domain features of the candidate spikes and the structural features of the FBN-PLV are input into the artificial neural network (ANN) to identify the spikes.
    UNASSIGNED: Based on FBN-PLV and ANN, the EEG data sets of four BECT cases from the Children\'s Hospital, Zhejiang University School of Medicine are tested with the AC of 97.6%, SE of 98.3%, and SP 96.8%.
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  • 文章类型: Journal Article
    计算机视觉在农业中的应用已经为从播种到收获的现有田间实践的重组做出了巨大贡献。在不同的植物部分中,经济部分,产量,具有最高的重要性,并成为农业社区的最终目标。这取决于许多遗传和环境因素,因此,这种对了解产量的好奇心带来了几种使用不同方式的精确收获前预测方法。在这些技术中,利用计算机视觉的非侵入性产量预测技术已被证明是最有效和可信的平台。这项研究开发了一种新的方法,叫做SlypNet,使用先进的深度学习网络,即,屏蔽R-CNN和U-Net,它可以从小麦植株的视觉图像中提取各种植物形态特征,如穗和小穗,并提供高精度的高通量产量估计。MaskR-CNN在尖峰检测方面的性能优于以前的网络,其平均平均精度(mAP)为97.57%,通过克服重叠和背景干扰等几个自然场约束,F1得分为0.67,MCC为0.91,可变分辨率,植物的茂密。小穗检测模块的准确性和一致性进行了测试,模型的验证准确性约为99%,误差最小,即,从一组典型的和复杂的小麦穗视图中得出1.3的均方误差。小穗产量累计显示了每株植物的可能生产能力。我们的方法提出了一个基于小穗的产量预测的集成深度学习平台,包括穗和小穗检测,导致比现有方法更高的精度。
    The application of computer vision in agriculture has already contributed immensely to restructuring the existing field practices starting from the sowing to the harvesting. Among the different plant parts, the economic part, the yield, has the highest importance and becomes the ultimate goal for the farming community. It depends on many genetic and environmental factors, so this curiosity about knowing the yield brought several precise pre-harvest prediction methods using different ways. Out of those techniques, non-invasive yield prediction techniques using computer vision have been proved to be the most efficient and trusted platform. This study developed a novel methodology, called SlypNet, using advanced deep learning networks, i.e., Mask R-CNN and U-Net, which can extract various plant morphological features like spike and spikelet from the visual image of the wheat plant and provide a high-throughput yield estimate with great precision. Mask R-CNN outperformed previous networks in spike detection by its precise detection performance with a mean average precision (mAP) of 97.57%, a F1 score of 0.67, and an MCC of 0.91 by overcoming several natural field constraints like overlapping and background interference, variable resolution, and high bushiness of plants. The spikelet detection module\'s accuracy and consistency were tested with about 99% validation accuracy of the model and the least error, i.e., a mean square error of 1.3 from a set of typical and complex views of wheat spikes. Spikelet yield cumulatively showed the probable production capability of each plant. Our method presents an integrated deep learning platform of spikelet-based yield prediction comprising spike and spikelet detection, leading to higher precision over the existing methods.
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  • 文章类型: Journal Article
    Automated analysis of small and optically variable plant organs, such as grain spikes, is highly demanded in quantitative plant science and breeding. Previous works primarily focused on the detection of prominently visible spikes emerging on the top of the grain plants growing in field conditions. However, accurate and automated analysis of all fully and partially visible spikes in greenhouse images renders a more challenging task, which was rarely addressed in the past. A particular difficulty for image analysis is represented by leaf-covered, occluded but also matured spikes of bushy crop cultivars that can hardly be differentiated from the remaining plant biomass. To address the challenge of automated analysis of arbitrary spike phenotypes in different grain crops and optical setups, here, we performed a comparative investigation of six neural network methods for pattern detection and segmentation in RGB images, including five deep and one shallow neural network. Our experimental results demonstrate that advanced deep learning methods show superior performance, achieving over 90% accuracy by detection and segmentation of spikes in wheat, barley and rye images. However, spike detection in new crop phenotypes can be performed more accurately than segmentation. Furthermore, the detection and segmentation of matured, partially visible and occluded spikes, for which phenotypes substantially deviate from the training set of regular spikes, still represent a challenge to neural network models trained on a limited set of a few hundreds of manually labeled ground truth images. Limitations and further potential improvements of the presented algorithmic frameworks for spike image analysis are discussed. Besides theoretical and experimental investigations, we provide a GUI-based tool (SpikeApp), which shows the application of pre-trained neural networks to fully automate spike detection, segmentation and phenotyping in images of greenhouse-grown plants.
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  • 文章类型: Journal Article
    In recent years, nano-impact electrochemistry (NIE) has attracted widespread attention as a new electroanalytical approach for the analysis and characterization of single nanoparticles in solution. The accurate analysis of the large volume of the experimental data is of great significance in improving the reliability of this method. Unfortunately, the commonly used data analysis approaches, mainly based on manual processing, are often time-consuming and subjective. Herein, we propose a spike detection algorithm for automatically processing the data from the direct oxidation of sliver nanoparticles (AgNPs) in NIE experiments, including baseline extraction, spike identification and spike area integration. The resulting size distribution of AgNPs is found to agree very well with that from transmission electron microscopy (TEM), showing that the current algorithm is promising for automated analysis of NIE data with high efficiency and accuracy.
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  • 文章类型: Journal Article
    Intracranial pressure (ICP) signals are often contaminated by artefacts and segments of missing values. Some of these artefacts can be observed as very high and short spikes with a physiologically impossible high slope. The presence of these spikes reduces the accuracy of pattern recognition techniques. Thus, we propose a modified empirical mode decomposition (EMD) method for spike removal in raw ICP signals. The EMD breaks down the signal into 16 intrinsic mode functions (IMFs), combines the first 4 to localize spikes using adaptive thresholding, and then either removes or imputes the identified ICP spikes.
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  • 文章类型: Journal Article
    微技术的进步使得可以同时记录的神经元数量呈指数趋势。然而,数据带宽需求随着信道计数而增加。涉及电生理学的绝大多数实验工作存储原始数据,然后离线处理;以检测潜在的尖峰事件。然而,新兴的应用程序需要新的方法,实时处理。
    我们开发了一种自适应,低复杂度的尖峰检测算法,其结合了三个新颖的分量,用于:(1)去除局部场电势;(2)增强信噪比;以及(3)计算自适应阈值。所提出的算法已经针对硬件实现进行了优化(即最小化计算,转换为定点实现),并在低功耗嵌入式目标上进行了演示。
    该算法已在合成数据集和真实记录上进行了验证,检测灵敏度高达90%。使用现成嵌入式平台的初始硬件实现表明,内存需求小于0.1kbROM和3kb程序闪存,消耗130μW的平均功率。
    提出的方法比其他方法有优势,它允许以完全自主的方式从神经活动中实时可靠地检测尖峰事件,不需要任何校准,并且可以在低硬件资源下实现。
    所提出的方法可以有效和自适应地检测尖峰。它减轻了重新校准的需要,这对于实现可行的BMI至关重要,未来的“高带宽”系统以1000个频道为目标,更是如此。
    The progress in microtechnology has enabled an exponential trend in the number of neurons that can be simultaneously recorded. The data bandwidth requirement is however increasing with channel count. The vast majority of experimental work involving electrophysiology stores the raw data and then processes this offline; to detect the underlying spike events. Emerging applications however require new methods for local, real-time processing.
    We have developed an adaptive, low complexity spike detection algorithm that combines three novel components for: (1) removing the local field potentials; (2) enhancing the signal-to-noise ratio; and (3) computing an adaptive threshold. The proposed algorithm has been optimised for hardware implementation (i.e. minimising computations, translating to a fixed-point implementation), and demonstrated on low-power embedded targets.
    The algorithm has been validated on both synthetic datasets and real recordings yielding a detection sensitivity of up to 90%. The initial hardware implementation using an off-the-shelf embedded platform demonstrated a memory requirement of less than 0.1 kb ROM and 3 kb program flash, consuming an average power of 130 μW.
    The method presented has the advantages over other approaches, that it allows spike events to be robustly detected in real-time from neural activity in a completely autonomous way, without the need for any calibration, and can be implemented with low hardware resources.
    The proposed method can detect spikes effectively and adaptively. It alleviates the need for re-calibration, which is critical towards achieving a viable BMI, and more so with future \'high bandwidth\' systems\' targeting 1000s of channels.
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  • 文章类型: Journal Article
    This study explores the generation of ultrafine particle emissions, measured in particle number (PN), based on a portable emissions measurement system (PEMS) in the City of Toronto between October and December 2019. Two driving routes were designed to include busy arterial roads and highways. All measurements were conducted between 10 a.m. and 4 p.m. Altogether, emissions from 31 drives were collected, leading to approximately 200,000 s of data. A spike detection algorithm was employed to isolate PN spikes in time series data. A sensitivity analysis was also conducted to identify the most optimum method for spike detection. The results indicate that the average emission rate during a PN spike is approximately 8 times the emission rate along the rest of the drive. In each test trip, about 25% of the duration was attributed to spike events, contributing 75% of total PN emissions. A Pearson correlation of 0.45 was estimated between the number of PN spikes and the number of sharp accelerations (above 8.5 km/h/s). The Pearson correlation between the occurrence of high engine torque (above 65.0 Nm) and the number of PN spikes was estimated at 0.80. The number of PN spikes was highest on arterial roads where the vehicle speed was relatively low, but with high variability, and including a high number of sharp accelerations. This pattern of UFP emissions leads to high UFP concentrations along arterial roads in the inner city core.
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  • 文章类型: Journal Article
    Visual evaluation of electroencephalogram (EEG) for Interictal Epileptiform Discharges (IEDs) as distinctive biomarkers of epilepsy has various limitations, including time-consuming reviews, steep learning curves, interobserver variability, and the need for specialized experts. The development of an automated IED detector is necessary to provide a faster and reliable diagnosis of epilepsy. In this paper, we propose an automated IED detector based on Convolutional Neural Networks (CNNs). We have evaluated the proposed IED detector on a sizable database of 554 scalp EEG recordings (84 epileptic patients and 461 nonepileptic subjects) recorded at Massachusetts General Hospital (MGH), Boston. The proposed CNN IED detector has achieved superior performance in comparison with conventional methods with a mean cross-validation area under the precision-recall curve (AUPRC) of 0.838[Formula: see text]±[Formula: see text]0.040 and false detection rate of 0.2[Formula: see text]±[Formula: see text]0.11 per minute for a sensitivity of 80%. We demonstrated the proposed system to be noninferior to 30 neurologists on a dataset from the Medical University of South Carolina (MUSC). Further, we clinically validated the system at National University Hospital (NUH), Singapore, with an agreement accuracy of 81.41% with a clinical expert. Moreover, the proposed system can be applied to EEG recordings with any arbitrary number of channels.
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  • 文章类型: Journal Article
    Spike is one of the crop yield organs in wheat plants. Determination of the phenological stages, including heading time point (HTP), and area of spike from non-invasive phenotyping images provides the necessary information for the inference of growth-related traits. The algorithm previously developed by Qiongyan et al. for spike detection in 2-D images turns out to be less accurate when applied to the European cultivars that produce many more leaves. Therefore, we here present an improved and extended method where (i) wavelet amplitude is used as an input to the Laws texture energy-based neural network instead of original grayscale images and (ii) non-spike structures (e.g., leaves) are subsequently suppressed by combining the result of the neural network prediction with a Frangi-filtered image. Using this two-step approach, a 98.6% overall accuracy of neural network segmentation based on direct comparison with ground-truth data could be achieved. Moreover, the comparative error rate in spike HTP detection and growth correlation among the ground truth, the algorithm developed by Qiongyan et al., and the proposed algorithm are discussed in this paper. The proposed algorithm was also capable of significantly reducing the error rate of the HTP detection by 75% and improving the accuracy of spike area estimation by 50% in comparison with the Qionagyan et al. method. With these algorithmic improvements, HTP detection on a diverse set of 369 plants was performed in a high-throughput manner. This analysis demonstrated that the HTP of 104 plants (comprises of 57 genotypes) with lower biomass and tillering range (e.g., earlier-heading types) were correctly determined. However, fine-tuning or extension of the developed method is required for high biomass plants where spike emerges within green bushes. In conclusion, our proposed method allows significantly more reliable results for HTP detection and spike growth analysis to be achieved in application to European cultivars with earlier-heading types.
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