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Star extraction by star sensors for daytime images affected by atmospheric turbulence
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作者 Wanxiang GOU Yinhu ZHAN +4 位作者 Chonghui LI Shuai TONG Yong ZHENG Yuan YANG Hanxu LI 《Chinese Journal of Aeronautics》 2025年第8期512-526,共15页
Daytime star images captured by dedicated near-space star sensors are characterized by short exposures,high noise,and low Signal-to-Noise Ratios(SNRs).Such imaging is also affected by atmospheric turbulence,causing op... Daytime star images captured by dedicated near-space star sensors are characterized by short exposures,high noise,and low Signal-to-Noise Ratios(SNRs).Such imaging is also affected by atmospheric turbulence,causing optical phenomena,such as scintillation,distortion,and jitter.This causes difficulty in recording high-precision star images during the daytime.This study proposes an adaptive star point extraction method based on dynamically predicting stars'positions.First,it predicts the approximate position of stars based on the star catalog,sensor attitude,observation time,and other information,improving the extraction accuracy.Second,it employs a regional SNR sorting method that adaptively selects star images with higher SNRs,suppressing the scintillation effect and enhancing the SNR of star images.Third,depending on the star's motion trajectory characteristics on the image plane,it utilizes the centroid smoothing method for extraction,thus overcoming the impact of star drift.Field experiments demonstrate that the proposed method can effectively overcome star scintillation,drift,and irregular imaging caused by atmospheric turbulence,achieving a 100%success rate.Moreover,the extraction accuracy improves by more than 80%compared to traditional adaptive methods,attaining a value of 0.05 pixels(0.5"),thereby meeting the requirements of daytime astronomical attitude determination and positioning. 展开更多
关键词 Astronomical navigation Atmospheric turbulence centroid accuracy Daytime star image Star extraction Star sensor
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Feature Extraction by Multi-Scale Principal Component Analysis and Classification in Spectral Domain 被引量:2
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作者 Shengkun Xie Anna T. Lawnizak +1 位作者 Pietro Lio Sridhar Krishnan 《Engineering(科研)》 2013年第10期268-271,共4页
Feature extraction of signals plays an important role in classification problems because of data dimension reduction property and potential improvement of a classification accuracy rate. Principal component analysis (... Feature extraction of signals plays an important role in classification problems because of data dimension reduction property and potential improvement of a classification accuracy rate. Principal component analysis (PCA), wavelets transform or Fourier transform methods are often used for feature extraction. In this paper, we propose a multi-scale PCA, which combines discrete wavelet transform, and PCA for feature extraction of signals in both the spatial and temporal domains. Our study shows that the multi-scale PCA combined with the proposed new classification methods leads to high classification accuracy for the considered signals. 展开更多
关键词 multi-scale Principal Component Analysis Discrete WAVELET TRANSFORM FEATURE extraction Signal CLASSIFICATION Empirical CLASSIFICATION
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Multi-Scale Mixed Attention Tea Shoot Instance Segmentation Model 被引量:1
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作者 Dongmei Chen Peipei Cao +5 位作者 Lijie Yan Huidong Chen Jia Lin Xin Li Lin Yuan Kaihua Wu 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第2期261-275,共15页
Tea leaf picking is a crucial stage in tea production that directly influences the quality and value of the tea.Traditional tea-picking machines may compromise the quality of the tea leaves.High-quality teas are often... Tea leaf picking is a crucial stage in tea production that directly influences the quality and value of the tea.Traditional tea-picking machines may compromise the quality of the tea leaves.High-quality teas are often handpicked and need more delicate operations in intelligent picking machines.Compared with traditional image processing techniques,deep learning models have stronger feature extraction capabilities,and better generalization and are more suitable for practical tea shoot harvesting.However,current research mostly focuses on shoot detection and cannot directly accomplish end-to-end shoot segmentation tasks.We propose a tea shoot instance segmentation model based on multi-scale mixed attention(Mask2FusionNet)using a dataset from the tea garden in Hangzhou.We further analyzed the characteristics of the tea shoot dataset,where the proportion of small to medium-sized targets is 89.9%.Our algorithm is compared with several mainstream object segmentation algorithms,and the results demonstrate that our model achieves an accuracy of 82%in recognizing the tea shoots,showing a better performance compared to other models.Through ablation experiments,we found that ResNet50,PointRend strategy,and the Feature Pyramid Network(FPN)architecture can improve performance by 1.6%,1.4%,and 2.4%,respectively.These experiments demonstrated that our proposed multi-scale and point selection strategy optimizes the feature extraction capability for overlapping small targets.The results indicate that the proposed Mask2FusionNet model can perform the shoot segmentation in unstructured environments,realizing the individual distinction of tea shoots,and complete extraction of the shoot edge contours with a segmentation accuracy of 82.0%.The research results can provide algorithmic support for the segmentation and intelligent harvesting of premium tea shoots at different scales. 展开更多
关键词 Tea shoots attention mechanism multi-scale feature extraction instance segmentation deep learning
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Ship recognition based on HRRP via multi-scale sparse preserving method
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作者 YANG Xueling ZHANG Gong SONG Hu 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第3期599-608,共10页
In order to extract the richer feature information of ship targets from sea clutter, and address the high dimensional data problem, a method termed as multi-scale fusion kernel sparse preserving projection(MSFKSPP) ba... In order to extract the richer feature information of ship targets from sea clutter, and address the high dimensional data problem, a method termed as multi-scale fusion kernel sparse preserving projection(MSFKSPP) based on the maximum margin criterion(MMC) is proposed for recognizing the class of ship targets utilizing the high-resolution range profile(HRRP). Multi-scale fusion is introduced to capture the local and detailed information in small-scale features, and the global and contour information in large-scale features, offering help to extract the edge information from sea clutter and further improving the target recognition accuracy. The proposed method can maximally preserve the multi-scale fusion sparse of data and maximize the class separability in the reduced dimensionality by reproducing kernel Hilbert space. Experimental results on the measured radar data show that the proposed method can effectively extract the features of ship target from sea clutter, further reduce the feature dimensionality, and improve target recognition performance. 展开更多
关键词 ship target recognition high-resolution range profile(HRRP) multi-scale fusion kernel sparse preserving projection(MSFKSPP) feature extraction dimensionality reduction
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Underwater Image Enhancement Based on Multi-scale Adversarial Network
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作者 ZENG Jun-yang SI Zhan-jun 《印刷与数字媒体技术研究》 CAS 北大核心 2024年第5期70-77,共8页
In this study,an underwater image enhancement method based on multi-scale adversarial network was proposed to solve the problem of detail blur and color distortion in underwater images.Firstly,the local features of ea... In this study,an underwater image enhancement method based on multi-scale adversarial network was proposed to solve the problem of detail blur and color distortion in underwater images.Firstly,the local features of each layer were enhanced into the global features by the proposed residual dense block,which ensured that the generated images retain more details.Secondly,a multi-scale structure was adopted to extract multi-scale semantic features of the original images.Finally,the features obtained from the dual channels were fused by an adaptive fusion module to further optimize the features.The discriminant network adopted the structure of the Markov discriminator.In addition,by constructing mean square error,structural similarity,and perceived color loss function,the generated image is consistent with the reference image in structure,color,and content.The experimental results showed that the enhanced underwater image deblurring effect of the proposed algorithm was good and the problem of underwater image color bias was effectively improved.In both subjective and objective evaluation indexes,the experimental results of the proposed algorithm are better than those of the comparison algorithm. 展开更多
关键词 Underwater image enhancement Generative adversarial network multi-scale feature extraction Residual dense block
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A multi-scale convolutional auto-encoder and its application in fault diagnosis of rolling bearings 被引量:12
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作者 Ding Yunhao Jia Minping 《Journal of Southeast University(English Edition)》 EI CAS 2019年第4期417-423,共7页
Aiming at the difficulty of fault identification caused by manual extraction of fault features of rotating machinery,a one-dimensional multi-scale convolutional auto-encoder fault diagnosis model is proposed,based on ... Aiming at the difficulty of fault identification caused by manual extraction of fault features of rotating machinery,a one-dimensional multi-scale convolutional auto-encoder fault diagnosis model is proposed,based on the standard convolutional auto-encoder.In this model,the parallel convolutional and deconvolutional kernels of different scales are used to extract the features from the input signal and reconstruct the input signal;then the feature map extracted by multi-scale convolutional kernels is used as the input of the classifier;and finally the parameters of the whole model are fine-tuned using labeled data.Experiments on one set of simulation fault data and two sets of rolling bearing fault data are conducted to validate the proposed method.The results show that the model can achieve 99.75%,99.3%and 100%diagnostic accuracy,respectively.In addition,the diagnostic accuracy and reconstruction error of the one-dimensional multi-scale convolutional auto-encoder are compared with traditional machine learning,convolutional neural networks and a traditional convolutional auto-encoder.The final results show that the proposed model has a better recognition effect for rolling bearing fault data. 展开更多
关键词 fault diagnosis deep learning convolutional auto-encoder multi-scale convolutional kernel feature extraction
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Modified Fourier descriptor for shape feature extraction 被引量:1
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作者 张刚 马宗民 +1 位作者 牛连强 张纯明 《Journal of Central South University》 SCIE EI CAS 2012年第2期488-495,共8页
A modified Fourier descriptor was presented. Information from a local space can be used more efficiently. After the boundary pixel set of an object was computed, centroid distance approach was used to compute shape si... A modified Fourier descriptor was presented. Information from a local space can be used more efficiently. After the boundary pixel set of an object was computed, centroid distance approach was used to compute shape signature in the local space. A pair of shape signature and boundary pixel gray was used as a point in a feature space. Then, Fourier transform was used for composition of point information in the feature space so that the shape features could be computed. It is proved theoretically that the shape features from modified Fourier descriptors are invariant to translation, rotation, scaling, and change of start point. It is also testified by measuring the retrieval performance of the systems that the shape features from modified Fourier oescriptors are more discriminative than those from other Fourier descriptors. 展开更多
关键词 shape feature extraction Fourier descriptors centroid distance approach
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哈特曼传感器检测微透镜波前方法
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作者 杨伟斌 王春艳 +4 位作者 张为国 王金玉 夏良平 杜春雷 孙昊 《应用光学》 北大核心 2025年第2期380-387,共8页
随着微透镜的广泛应用,微透镜光学性能的快速检测是使用者和加工人员亟待解决的关键问题。提出利用哈特曼波前传感器来检测微透镜波前,从而快速表征其光学性能。为了验证该方法的可行性,设计了利用哈特曼传感器测量微透镜波前的总体方案... 随着微透镜的广泛应用,微透镜光学性能的快速检测是使用者和加工人员亟待解决的关键问题。提出利用哈特曼波前传感器来检测微透镜波前,从而快速表征其光学性能。为了验证该方法的可行性,设计了利用哈特曼传感器测量微透镜波前的总体方案,搭建了测量实验系统,并对测量的误差源进行了分析。结合实验方案,研究质心提取算法、Zernike多项式波前重构算法,保证光斑质心提取精度及波前重构精度,并分析了待测透镜孔径衍射对波前检测精度的影响。结合200μm的凸透镜进行波前检测实验,得到了其波前误差和初级像差信息,为微透镜光学性能的快速检测提供了一种全新的思路。 展开更多
关键词 微透镜 哈特曼传感器 质心提取 波前重构 光学性能
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基于单相机的空间目标相对位姿测量系统
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作者 支帅 丁国鹏 +2 位作者 韩世豪 张永合 朱振才 《中国光学(中英文)》 北大核心 2025年第5期1111-1123,共13页
为提高测量系统的稳定性及精度,实现航天器超近距离高精度对接,本文提出了一种基于单相机及合作靶标的相对位姿测量系统,用于双星间相对位置及姿态的高精度测量。通过设计追踪星视觉相机及目标星LED合作靶标,在双星距离为50米到0.4米的... 为提高测量系统的稳定性及精度,实现航天器超近距离高精度对接,本文提出了一种基于单相机及合作靶标的相对位姿测量系统,用于双星间相对位置及姿态的高精度测量。通过设计追踪星视觉相机及目标星LED合作靶标,在双星距离为50米到0.4米的范围内,实现了高精度的相对位姿测量。通过设计远近场LED靶标,实现了相机与靶标间的协同工作,保证在50米到0.4米的距离均能清晰成像;根据设计的靶标特性,提出了多尺度质心提取算法,利用斜率一致性约束与间距比筛选,在复杂光照下能稳定获取特征目标;最后,结合靶标几何约束的初值估计,实现了目标星相对于追踪星的位姿解算,为进一步提高测量精度,引入非线性优化方法对位姿结果进行迭代优化,有效降低了测量误差。试验结果表明,系统测量精度由远及近逐渐提高,在距离为0.4m时,位置测量精度优于1mm,姿态测量精度优于0.2°,满足超近距离对接任务需求。本方案为空间在轨目标相对位姿测量提供了高精度、高稳定性的技术支撑,具有重要的工程应用价值。 展开更多
关键词 单相机 LED合作靶标 多尺度质心提取 非线性优化 相对位姿测量
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大跨度高精度光斑质心提取
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作者 高豆豆 韩奕璇 +3 位作者 董登峰 王博 邱启帆 崔成君 《光学精密工程》 北大核心 2025年第17期2691-2703,共13页
针对合作靶标特征点成像在大跨度动态测量中的特征提取精度下降、实时性不足问题,提出了一种融合帧间运动预测与改进亚像素边缘检测的自适应光斑质心提取方法。基于合作靶标测量运动连贯性特性,构建了动态感兴趣区域(Region of Interest... 针对合作靶标特征点成像在大跨度动态测量中的特征提取精度下降、实时性不足问题,提出了一种融合帧间运动预测与改进亚像素边缘检测的自适应光斑质心提取方法。基于合作靶标测量运动连贯性特性,构建了动态感兴趣区域(Region of Interest,ROI)特征参数模型,以帧间运动预测实现ROI的快速定位,结合大律法阈值优化策略实现自适应Canny边缘检测,在提升计算效率的同时有效解决了不同测量距离下的降噪问题。然后,采用多方向Sobel算子与强度斜坡改进的Zernike矩相结合改进了边缘点定位算法,并基于高斯牛顿迭代改进鲁棒最小二乘圆拟合法,实现质心坐标计算。实验结果表明:在仿真测试中,本方法在不同噪声水平下的质心定位误差为0.001~0.025像素;实际测试中,ROI预测算法可满足加速度8.75 m/s^(2)以内的测量场景需求,10~30 m测量距离内的光斑重复性定位误差稳定在0.016~0.040像素,优于传统方法;光斑提取速度提升约75.5%,显著增强了系统的实时处理能力。本研究可为合作靶标的测量应用提供有效技术保障。 展开更多
关键词 合作靶标检测 自适应光斑质心提取 帧间运动预测 改进的Sobel-Zernike矩
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A Weakly Supervised Semantic Segmentation Method Based on Improved Conformer
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作者 Xueli Shen Meng Wang 《Computers, Materials & Continua》 2025年第3期4631-4647,共17页
In the field of Weakly Supervised Semantic Segmentation(WSSS),methods based on image-level annotation face challenges in accurately capturing objects of varying sizes,lacking sensitivity to image details,and having hi... In the field of Weakly Supervised Semantic Segmentation(WSSS),methods based on image-level annotation face challenges in accurately capturing objects of varying sizes,lacking sensitivity to image details,and having high computational costs.To address these issues,we improve the dual-branch architecture of the Conformer as the fundamental network for generating class activation graphs,proposing a multi-scale efficient weakly-supervised semantic segmentation method based on the improved Conformer.In the Convolution Neural Network(CNN)branch,a cross-scale feature integration convolution module is designed,incorporating multi-receptive field convolution layers to enhance the model’s ability to capture long-range dependencies and improve sensitivity to multi-scale objects.In the Vision Transformer(ViT)branch,an efficient multi-head self-attention module is developed,reducing unnecessary computation through spatial compression and feature partitioning,thereby improving overall network efficiency.Finally,a multi-feature coupling module is introduced to complement the features generated by both branches.This design retains the strength of Convolution Neural Network in extracting local details while harnessing the strength of Vision Transformer to capture comprehensive global features.Experimental results show that the mean Intersection over Union of the image segmentation results of the proposed method on the validation and test sets of the PASCAL VOC 2012 datasets are improved by 2.9%and 3.6%,respectively,over the TransCAM algorithm.Besides,the improved model demonstrates a 1.3%increase of the mean Intersections over Union on the COCO 2014 datasets.Additionally,the number of parameters and the floating-point operations are reduced by 16.2%and 12.9%.However,the proposed method still has limitations of poor performance when dealing with complex scenarios.There is a need for further enhancing the performance of this method to address this issue. 展开更多
关键词 WSSS CAM transformer CNN multi-scale feature extraction LIGHTWEIGHT
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BSDNet:Semantic Information Distillation-Based for Bilateral-Branch Real-Time Semantic Segmentation on Street Scene Image
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作者 Huan Zeng Jianxun Zhang +1 位作者 Hongji Chen Xinwei Zhu 《Computers, Materials & Continua》 2025年第11期3879-3896,共18页
Semantic segmentation in street scenes is a crucial technology for autonomous driving to analyze the surrounding environment.In street scenes,issues such as high image resolution caused by a large viewpoints and diffe... Semantic segmentation in street scenes is a crucial technology for autonomous driving to analyze the surrounding environment.In street scenes,issues such as high image resolution caused by a large viewpoints and differences in object scales lead to a decline in real-time performance and difficulties in multi-scale feature extraction.To address this,we propose a bilateral-branch real-time semantic segmentationmethod based on semantic information distillation(BSDNet)for street scene images.The BSDNet consists of a Feature Conversion Convolutional Block(FCB),a Semantic Information Distillation Module(SIDM),and a Deep Aggregation Atrous Convolution Pyramid Pooling(DASP).FCB reduces the semantic gap between the backbone and the semantic branch.SIDM extracts high-quality semantic information fromthe Transformer branch to reduce computational costs.DASP aggregates information lost in atrous convolutions,effectively capturingmulti-scale objects.Extensive experiments conducted on Cityscapes,CamVid,and ADE20K,achieving an accuracy of 81.7% Mean Intersection over Union(mIoU)at 70.6 Frames Per Second(FPS)on Cityscapes,demonstrate that our method achieves a better balance between accuracy and inference speed. 展开更多
关键词 Street scene understanding real-time semantic segmentation knowledge distillation multi-scale feature extraction
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A 3D semantic segmentation network for accurate neuronal soma segmentation
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作者 Li Ma Qi Zhong +2 位作者 Yezi Wang Xiaoquan Yang Qian Du 《Journal of Innovative Optical Health Sciences》 2025年第1期67-83,共17页
Neuronal soma segmentation plays a crucial role in neuroscience applications.However,the fine structure,such as boundaries,small-volume neuronal somata and fibers,are commonly present in cell images,which pose a chall... Neuronal soma segmentation plays a crucial role in neuroscience applications.However,the fine structure,such as boundaries,small-volume neuronal somata and fibers,are commonly present in cell images,which pose a challenge for accurate segmentation.In this paper,we propose a 3D semantic segmentation network for neuronal soma segmentation to address this issue.Using an encoding-decoding structure,we introduce a Multi-Scale feature extraction and Adaptive Weighting fusion module(MSAW)after each encoding block.The MSAW module can not only emphasize the fine structures via an upsampling strategy,but also provide pixel-wise weights to measure the importance of the multi-scale features.Additionally,a dynamic convolution instead of normal convolution is employed to better adapt the network to input data with different distributions.The proposed MSAW-based semantic segmentation network(MSAW-Net)was evaluated on three neuronal soma images from mouse brain and one neuronal soma image from macaque brain,demonstrating the efficiency of the proposed method.It achieved an F1 score of 91.8%on Fezf2-2A-CreER dataset,97.1%on LSL-H2B-GFP dataset,82.8%on Thy1-EGFP-Mline dataset,and 86.9%on macaque dataset,achieving improvements over the 3D U-Net model by 3.1%,3.3%,3.9%,and 2.3%,respectively. 展开更多
关键词 Neuronal soma segmentation semantic segmentation network multi-scale feature extraction adaptive weighting fusion
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基于改进的三角形星图识别算法的空间目标天文定位方法
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作者 张桐溯 汪瀚 +2 位作者 陈思洋 杨夏 张小虎 《载人航天》 北大核心 2025年第5期594-603,共10页
空间目标天文定位是空间监视中常用的高精度定位方式,其中星图识别技术是实现目标精确定位的关键。针对传统三角形星图识别算法在大视场下存在导航星库构建复杂、冗余结果多的问题,提出一种改进方法。在星点提取与质心精定位基础上,引入... 空间目标天文定位是空间监视中常用的高精度定位方式,其中星图识别技术是实现目标精确定位的关键。针对传统三角形星图识别算法在大视场下存在导航星库构建复杂、冗余结果多的问题,提出一种改进方法。在星点提取与质心精定位基础上,引入4颗特征星构建广义三角形,并结合星对表分区间快速遍历策略提升识别效率,同时构建理论参考星图。基于大视场望远镜星图数据的对比实验表明:改进的三角形法相较传统方法匹配成功率提升46.0%,冗余数减少98.4%,相较多边形法以及栅格法匹配成功率分别提高10.0%和35.5%;最终天文定位平均误差低于20角秒。结果表明该方法在大视场天文定位中的优越性。 展开更多
关键词 模式识别 星图识别 天文定位 改进的三角形星图识别算法 星点质心提取
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Attention⁃Based Multi⁃scale CNN and LSTM Model for Remaining Useful Life Estimation
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作者 DUAN Jiajun LU Zhong DU Zhiqiang 《Transactions of Nanjing University of Aeronautics and Astronautics》 2025年第S1期64-77,共14页
Current aero-engine life prediction areas typically focus on single-scale degradation features,and the existing methods are not comprehensive enough to capture the relationship within time series data.To address this ... Current aero-engine life prediction areas typically focus on single-scale degradation features,and the existing methods are not comprehensive enough to capture the relationship within time series data.To address this problem,we propose a novel remaining useful life(RUL)estimation method based on the attention mechanism.Our approach designs a two-layer multi-scale feature extraction module that integrates degradation features at different scales.These features are then processed in parallel by a self-attention module and a three-layer long short-term memory(LSTM)network,which together capture long-term dependencies and adaptively weigh important feature.The integration of degradation patterns from both components into the attention module enhances the model’s ability to capture long-term dependencies.Visualizing the attention module’s weight matrices further improves model interpretability.Experimental results on the C-MAPSS dataset demonstrate that our approach outperforms the existing state-of-the-art methods. 展开更多
关键词 attention mechanism convolutional neural network(CNN) long short-term memory(LSTM) multi-scale feature extraction
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基于DSM和DEM的建筑物高度自动提取方法研究
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作者 张海 张飞 +1 位作者 任光耀 侯恩兵 《测绘与空间地理信息》 2025年第1期53-56,共4页
随着城市化进程的加速和城市国土空间监测工作的持续深化,精确测定大区域建筑物的高度已成为一个亟待解决的重要议题。本文深入探讨了基于数字表面模型(DSM)和数字高程模型(DEM)的建筑物高度自动提取方法。结合中心点算法、均值算法和... 随着城市化进程的加速和城市国土空间监测工作的持续深化,精确测定大区域建筑物的高度已成为一个亟待解决的重要议题。本文深入探讨了基于数字表面模型(DSM)和数字高程模型(DEM)的建筑物高度自动提取方法。结合中心点算法、均值算法和统计算法,并对这些方法在实际应用中的表现进行了详细的对比分析,评估方法的精度和可靠性,进一步探讨在不同场景下的适用性。同时通过对数据处理流程的优化和算法的改进,为城市国土空间监测和城市级实景三维建设任务等相关领域提供一种高效、准确的建筑物高度信息获取手段。 展开更多
关键词 建筑物高度提取 中心点算法 均值算法 统计算法 城市级实景三维
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基于单目视觉的火箭回收高度测量技术研究 被引量:4
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作者 路荣 张高鹏 +6 位作者 曹剑中 陈卫宁 郭惠楠 张海峰 张哲 梅超 关蕾 《光学精密工程》 EI CAS CSCD 北大核心 2024年第14期2166-2188,共23页
精确测量火箭实时高度是完成火箭回收任务的重要前提之一,为了实现对火箭高度的实时测量,本文对基于单目视觉的火箭回收高度测量技术进行了研究。首先针对火箭回收过程中的烟雾场景,在何凯明暗通道去雾算法的基础上,结合视网膜大脑皮层(... 精确测量火箭实时高度是完成火箭回收任务的重要前提之一,为了实现对火箭高度的实时测量,本文对基于单目视觉的火箭回收高度测量技术进行了研究。首先针对火箭回收过程中的烟雾场景,在何凯明暗通道去雾算法的基础上,结合视网膜大脑皮层(Retinex)理论对透射率函数进行改进,从而提升了去雾算法对不同雾环境下的适应性。其次,针对火箭回收中靶点的特性,提出了适用于靶点特征提取的算法,并设计实验验证了算法的可行性与可靠性。针对火箭与地面靶点的几何特性构建了数学模型,并设计实验定量分析了高度解算算法的可行性。最后定量分析了不同雾浓度下不同去雾算法对高度测量结果的影响。仿真和实物实验结果表明,根据本文提出方法计算得到的火箭高度解算精度在0.5 m以内,可满足火箭回收中对高度测量的需求。 展开更多
关键词 火箭回收 单幅图像去雾 质心提取 高度解算 单目视觉
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考虑综合相似性度量的光伏典型出力场景聚类方法 被引量:6
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作者 程雄 戴鹏 +2 位作者 钟浩 李咸善 李文武 《中国电机工程学报》 EI CSCD 北大核心 2024年第21期8462-8474,I0011,共14页
场景聚类是描述不确定性光伏典型出力特性的有效途径之一,如何度量波动繁杂的光伏发电曲线相似性以及生成具有代表性的光伏出力场景是目前亟需解决的问题。为此,提出一种考虑综合相似性度量的光伏典型出力场景聚类方法,其基本思路是首... 场景聚类是描述不确定性光伏典型出力特性的有效途径之一,如何度量波动繁杂的光伏发电曲线相似性以及生成具有代表性的光伏出力场景是目前亟需解决的问题。为此,提出一种考虑综合相似性度量的光伏典型出力场景聚类方法,其基本思路是首先考虑光伏发电的电量大小、形态趋势、波动位置相似性,得到适用于光伏发电曲线的综合相似性度量距离;其次将形态质心作为优化问题求解,再用同倍比放大法得到兼顾电量和形态的实际质心,针对传统聚类算法在初始中心确定等方面的不足,以二十四节气为区间提出基于改进K-means算法的光伏典型场景集生成模型;最后构建光伏发电场景集指标评价体系,以熵权Topsis法对典型出力场景集进行综合评价。云南某地装机50MW的光伏电站2018—2020年算例结果表明:该文算法能准确划分和提取典型光伏出力场景,且以节气为区间生成的典型场景集在波动和电量指标上都有较好的表现,证明算法的有效性。 展开更多
关键词 相似性度量 聚类质心提取 光伏场景生成 典型场景集评价 K-MEANS算法
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基于改进高斯拟合的红外相机视角下标识点中心定位方法 被引量:2
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作者 鲍勃屹 张辉 +2 位作者 朱成顺 郑天宇 张震 《激光杂志》 CAS 北大核心 2024年第4期59-64,共6页
针对红外相机视角下标识点中心提取问题,在分析其图像特征的基础上,提出一种粗细结合的分割及高斯拟合的方法以实现对标识点中心的定位。首先根据图像中标识点的灰度差异,对其进行ROI粗定位,去除背景反光对其分割的影响。随后对目标图... 针对红外相机视角下标识点中心提取问题,在分析其图像特征的基础上,提出一种粗细结合的分割及高斯拟合的方法以实现对标识点中心的定位。首先根据图像中标识点的灰度差异,对其进行ROI粗定位,去除背景反光对其分割的影响。随后对目标图像采用K均值聚类算法,实现目标分割。最后,通过剔除中心冗余信息的改进高斯拟合提取方法,得到标识点光斑中心坐标。实验结果表明,相较于灰度质心法、Hough变换法和圆拟合法,本方法对其中心提取稳定性误差均小于0.1像素,具有高重复性和稳定性精度。即使目标产生不同程度遮挡时仍具有较高精度,适合于红外相机视角下定位系统的标识点中心提取。 展开更多
关键词 光斑检测 图像分割 中心提取 光学测量
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基于贝塞尔曲面拟合的子光斑背景噪声去除方法 被引量:1
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作者 郭晗 赵旺 +5 位作者 王帅 杨平 闫力松 刘生虎 官泓利 赵晨思 《光子学报》 EI CAS CSCD 北大核心 2024年第8期52-67,共16页
受天光背景影响,夏克-哈特曼波前传感器子光斑图像背景光增强,导致子光斑质心位置无法准确提取,使得波前传感器探测精度下降。为提高强天光背景影响下波前传感器探测精度,提出了一种基于贝塞尔曲面拟合的背景噪声去除算法。该算法利用... 受天光背景影响,夏克-哈特曼波前传感器子光斑图像背景光增强,导致子光斑质心位置无法准确提取,使得波前传感器探测精度下降。为提高强天光背景影响下波前传感器探测精度,提出了一种基于贝塞尔曲面拟合的背景噪声去除算法。该算法利用贝塞尔曲面拟合背景噪声,不受拟合基函数约束,实现背景噪声与目标光斑信号的有效分离。仿真和实验结果均表明,所提方法对背景噪声的拟合精度不受目标光斑信号的影响,在保证目标光斑信号完整的前提下,能有效拟合非均匀分布背景噪声,相比传统阈值法、加窗法等,在背信比范围为30至120的强天光背景干扰下,将波前探测精度提升约33%。 展开更多
关键词 自适应光学 质心提取 曲面拟合 波前复原 背景干扰
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