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Global context-aware multi-scale feature iterative refinement for aviation-road traffic semantic segmentation
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作者 Mengyue ZHANG Shichun YANG +1 位作者 Xinjie FENG Yaoguang CAO 《Chinese Journal of Aeronautics》 2026年第2期429-441,共13页
Semantic segmentation for mixed scenes of aerial remote sensing and road traffic is one of the key technologies for visual perception of flying cars.The State-of-the-Art(SOTA)semantic segmentation methods have made re... Semantic segmentation for mixed scenes of aerial remote sensing and road traffic is one of the key technologies for visual perception of flying cars.The State-of-the-Art(SOTA)semantic segmentation methods have made remarkable achievements in both fine-grained segmentation and real-time performance.However,when faced with the huge differences in scale and semantic categories brought about by the mixed scenes of aerial remote sensing and road traffic,they still face great challenges and there is little related research.Addressing the above issue,this paper proposes a semantic segmentation model specifically for mixed datasets of aerial remote sensing and road traffic scenes.First,a novel decoding-recoding multi-scale feature iterative refinement structure is proposed,which utilizes the re-integration and continuous enhancement of multi-scale information to effectively deal with the huge scale differences between cross-domain scenes,while using a fully convolutional structure to ensure the lightweight and real-time requirements.Second,a welldesigned cross-window attention mechanism combined with a global information integration decoding block forms an enhanced global context perception,which can effectively capture the long-range dependencies and multi-scale global context information of different scenes,thereby achieving fine-grained semantic segmentation.The proposed method is tested on a large-scale mixed dataset of aerial remote sensing and road traffic scenes.The results confirm that it can effectively deal with the problem of large-scale differences in cross-domain scenes.Its segmentation accuracy surpasses that of the SOTA methods,which meets the real-time requirements. 展开更多
关键词 Aviation-road traffic Flying cars Global context-aware Multi-scale feature iterative refinement Semantic segmentation
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High-Performance Segmentation of Power Lines in Aerial Images Using a Wavelet-Guided Hybrid Transformer Network
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作者 Burhan Baraklı Ahmet Küçüker 《Computer Modeling in Engineering & Sciences》 2026年第2期772-802,共31页
Inspections of power transmission lines(PTLs)conducted using unmanned aerial vehicles(UAVs)are complicated by the fine structure of the lines and complex backgrounds,making accurate and efficient segmentation challeng... Inspections of power transmission lines(PTLs)conducted using unmanned aerial vehicles(UAVs)are complicated by the fine structure of the lines and complex backgrounds,making accurate and efficient segmentation challenging.This study presents the Wavelet-Guided Transformer U-Net(WGT-UNet)model,a new hybrid net-work that combines Convolutional Neural Networks(CNNs),Discrete Wavelet Transform(DWT),and Transformer architectures.The model’s primary contribution is based on spatial and channel attention mechanisms derived from wavelet subbands to guide the Transformer’s self-attention structure.Thus,low and high frequency components are separated at each stage using DWT,suppressing structural noise and making linear objects more prominent.The developed design is supported by multi-component hybrid cost functions that simultaneously solve class imbalance,edge sharpness,structural integrity,and spatial regularity issues.Furthermore,high segmentation success has been achieved in producing sharp boundaries and continuous line structures with the DWT-guided attention mechanism.Experiments conducted on the TTPLA dataset reveal that the version using the ConvNeXt backbone outperforms the current state-of-the-art approaches with an F1-Score of 79.33%and an Intersection over Union(IoU)value of 68.38%.The models and visual outputs of the developed method and all compared models can be accessed at https://github.com/burhanbarakli/WGT-UNET. 展开更多
关键词 Salient object detection superpixel segmentation TRANSFORMERS attention mechanism multi-level fusion edge-preserving refinement model-driven
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MLRT-UNet:An Efficient Multi-Level Relation Transformer Based U-Net for Thyroid Nodule Segmentation
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作者 Kaku Haribabu Prasath R Praveen Joe IR 《Computer Modeling in Engineering & Sciences》 2025年第4期413-448,共36页
Thyroid nodules,a common disorder in the endocrine system,require accurate segmentation in ultrasound images for effective diagnosis and treatment.However,achieving precise segmentation remains a challenge due to vari... Thyroid nodules,a common disorder in the endocrine system,require accurate segmentation in ultrasound images for effective diagnosis and treatment.However,achieving precise segmentation remains a challenge due to various factors,including scattering noise,low contrast,and limited resolution in ultrasound images.Although existing segmentation models have made progress,they still suffer from several limitations,such as high error rates,low generalizability,overfitting,limited feature learning capability,etc.To address these challenges,this paper proposes a Multi-level Relation Transformer-based U-Net(MLRT-UNet)to improve thyroid nodule segmentation.The MLRTUNet leverages a novel Relation Transformer,which processes images at multiple scales,overcoming the limitations of traditional encoding methods.This transformer integrates both local and global features effectively through selfattention and cross-attention units,capturing intricate relationships within the data.The approach also introduces a Co-operative Transformer Fusion(CTF)module to combine multi-scale features from different encoding layers,enhancing the model’s ability to capture complex patterns in the data.Furthermore,the Relation Transformer block enhances long-distance dependencies during the decoding process,improving segmentation accuracy.Experimental results showthat the MLRT-UNet achieves high segmentation accuracy,reaching 98.2% on the Digital Database Thyroid Image(DDT)dataset,97.8% on the Thyroid Nodule 3493(TG3K)dataset,and 98.2% on the Thyroid Nodule3K(TN3K)dataset.These findings demonstrate that the proposed method significantly enhances the accuracy of thyroid nodule segmentation,addressing the limitations of existing models. 展开更多
关键词 Thyroid nodules endocrine system multi-level relation transformer U-Net self-attention external attention co-operative transformer fusion thyroid nodules segmentation
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Retinal Vessel Segmentation via Adversarial Learning and Iterative Refinement 被引量:1
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作者 顾闻 徐奕 《Journal of Shanghai Jiaotong university(Science)》 EI 2024年第1期73-80,共8页
Retinal vessel segmentation is a challenging medical task owing to small size of dataset,micro blood vessels and low image contrast.To address these issues,we introduce a novel convolutional neural network in this pap... Retinal vessel segmentation is a challenging medical task owing to small size of dataset,micro blood vessels and low image contrast.To address these issues,we introduce a novel convolutional neural network in this paper,which takes the advantage of both adversarial learning and recurrent neural network.An iterative design of network with recurrent unit is performed to refine the segmentation results from input retinal image gradually.Recurrent unit preserves high-level semantic information for feature reuse,so as to output a sufficiently refined segmentation map instead of a coarse mask.Moreover,an adversarial loss is imposing the integrity and connectivity constraints on the segmented vessel regions,thus greatly reducing topology errors of segmentation.The experimental results on the DRIVE dataset show that our method achieves area under curve and sensitivity of 98.17%and 80.64%,respectively.Our method achieves superior performance in retinal vessel segmentation compared with other existing state-of-the-art methods. 展开更多
关键词 medical image processing retinal image segmentation adversarial learning iterative refinement
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EGSNet:An Efficient Glass Segmentation Network Based on Multi-Level Heterogeneous Architecture and Boundary Awareness
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作者 Guojun Chen Tao Cui +1 位作者 Yongjie Hou Huihui Li 《Computers, Materials & Continua》 SCIE EI 2024年第12期3969-3987,共19页
Existing glass segmentation networks have high computational complexity and large memory occupation,leading to high hardware requirements and time overheads for model inference,which is not conducive to efficiency-see... Existing glass segmentation networks have high computational complexity and large memory occupation,leading to high hardware requirements and time overheads for model inference,which is not conducive to efficiency-seeking real-time tasks such as autonomous driving.The inefficiency of the models is mainly due to employing homogeneous modules to process features of different layers.These modules require computationally intensive convolutions and weight calculation branches with numerous parameters to accommodate the differences in information across layers.We propose an efficient glass segmentation network(EGSNet)based on multi-level heterogeneous architecture and boundary awareness to balance the model performance and efficiency.EGSNet divides the feature layers from different stages into low-level understanding,semantic-level understanding,and global understanding with boundary guidance.Based on the information differences among the different layers,we further propose the multi-angle collaborative enhancement(MCE)module,which extracts the detailed information from shallow features,and the large-scale contextual feature extraction(LCFE)module to understand semantic logic through deep features.The models are trained and evaluated on the glass segmentation datasets HSO(Home-Scene-Oriented)and Trans10k-stuff,respectively,and EGSNet achieves the best efficiency and performance compared to advanced methods.In the HSO test set results,the IoU,Fβ,MAE(Mean Absolute Error),and BER(Balance Error Rate)of EGSNet are 0.804,0.847,0.084,and 0.085,and the GFLOPs(Giga Floating Point Operations Per Second)are only 27.15.Experimental results show that EGSNet significantly improves the efficiency of the glass segmentation task with better performance. 展开更多
关键词 Image segmentation multi-level heterogeneous architecture feature differences
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Fast segmentation approach for SAR image based on simple Markov random field 被引量:8
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作者 Xiaogang Lei Ying Li Na Zhao Yanning Zhang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第1期31-36,共6页
Traditional image segmentation methods based on MRF converge slowly and require pre-defined weight. These disadvantages are addressed, and a fast segmentation approach based on simple Markov random field (MRF) for S... Traditional image segmentation methods based on MRF converge slowly and require pre-defined weight. These disadvantages are addressed, and a fast segmentation approach based on simple Markov random field (MRF) for SAR image is proposed. The approach is firstly used to perform coarse segmentation in blocks. Then the image is modeled with simple MRF and adaptive variable weighting forms are applied in homogeneous and heterogeneous regions. As a result, the convergent speed is accelerated while the segmentation results in homogeneous regions and boarders are improved. Simulations with synthetic and real SAR images demonstrate the effectiveness of the proposed approach. 展开更多
关键词 SAR image segmentation simple Markov random field coarse segmentation maximum a posterior iterated condition mode.
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Improved SLIC Segmentation Algorithm for Artificial Structure Images 被引量:5
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作者 Jianzhong Wang Pengzhan Liu +1 位作者 Jiadong Shi Guodong Yan 《Journal of Beijing Institute of Technology》 EI CAS 2019年第3期418-427,共10页
Simple linear iterative cluster(SLIC) is widely used because controllable superpixel number, accurate edge covering, symmetrical production and fast speed of calculation. The main problem of the SLIC algorithm is its ... Simple linear iterative cluster(SLIC) is widely used because controllable superpixel number, accurate edge covering, symmetrical production and fast speed of calculation. The main problem of the SLIC algorithm is its under-segmentation when applied to segment artificial structure images with unobvious boundaries and narrow regions. Therefore, an improved clustering segmentation algorithm to correct the segmentation results of SLIC is presented in this paper. The allocation of pixels is not only related to its own characteristic, but also to those of its surrounding pixels.Hence, it is appropriate to improve the standard SLIC through the pixels by focusing on boundaries. An improved SLIC method adheres better to the boundaries in the image is proposed, by using the first and second order difference operators as magnified factors. Experimental results demonstrate that the proposed method achieves an excellent boundary adherence for artificial structure images. The application of the proposed method is extended to images with an unobvious boundary in the Berkeley Segmentation Dataset BSDS500. In comparison with SLIC, the boundary adherence is increased obviously. 展开更多
关键词 SIMPLE linear iterative CLUSTER (SLIC) segmentation superpixel image ENHANCEMENT
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A Local Contrast Fusion Based 3D Otsu Algorithm for Multilevel Image Segmentation 被引量:14
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作者 Ashish Kumar Bhandari Arunangshu Ghosh Immadisetty Vinod Kumar 《IEEE/CAA Journal of Automatica Sinica》 EI CSCD 2020年第1期200-213,共14页
To overcome the shortcomings of 1 D and 2 D Otsu’s thresholding techniques, the 3 D Otsu method has been developed.Among all Otsu’s methods, 3 D Otsu technique provides the best threshold values for the multi-level ... To overcome the shortcomings of 1 D and 2 D Otsu’s thresholding techniques, the 3 D Otsu method has been developed.Among all Otsu’s methods, 3 D Otsu technique provides the best threshold values for the multi-level thresholding processes. In this paper, to improve the quality of segmented images, a simple and effective multilevel thresholding method is introduced. The proposed approach focuses on preserving edge detail by computing the 3 D Otsu along the fusion phenomena. The advantages of the presented scheme include higher quality outcomes, better preservation of tiny details and boundaries and reduced execution time with rising threshold levels. The fusion approach depends upon the differences between pixel intensity values within a small local space of an image;it aims to improve localized information after the thresholding process. The fusion of images based on local contrast can improve image segmentation performance by minimizing the loss of local contrast, loss of details and gray-level distributions. Results show that the proposed method yields more promising segmentation results when compared to conventional1 D Otsu, 2 D Otsu and 3 D Otsu methods, as evident from the objective and subjective evaluations. 展开更多
关键词 1D Otsu 2D Otsu 3D Otsu image fusion local contrast multi-level image segmentation
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Improved Reptile Search Algorithm by Salp Swarm Algorithm for Medical Image Segmentation 被引量:3
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作者 Laith Abualigah Mahmoud Habash +4 位作者 Essam Said Hanandeh Ahmad MohdAziz Hussein Mohammad Al Shinwan Raed Abu Zitar Heming Jia 《Journal of Bionic Engineering》 SCIE EI CSCD 2023年第4期1766-1790,共25页
This study proposes a novel nature-inspired meta-heuristic optimizer based on the Reptile Search Algorithm combed with Salp Swarm Algorithm for image segmentation using gray-scale multi-level thresholding,called RSA-S... This study proposes a novel nature-inspired meta-heuristic optimizer based on the Reptile Search Algorithm combed with Salp Swarm Algorithm for image segmentation using gray-scale multi-level thresholding,called RSA-SSA.The proposed method introduces a better search space to find the optimal solution at each iteration.However,we proposed RSA-SSA to avoid the searching problem in the same area and determine the optimal multi-level thresholds.The obtained solutions by the proposed method are represented using the image histogram.The proposed RSA-SSA employed Otsu’s variance class function to get the best threshold values at each level.The performance measure for the proposed method is valid by detecting fitness function,structural similarity index,peak signal-to-noise ratio,and Friedman ranking test.Several benchmark images of COVID-19 validate the performance of the proposed RSA-SSA.The results showed that the proposed RSA-SSA outperformed other metaheuristics optimization algorithms published in the literature. 展开更多
关键词 BIOINSPIRED Reptile Search Algorithm Salp Swarm Algorithm multi-level thresholding Image segmentation Meta-heuristic algorithm
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A Novel Method for Automated Lung Region Segmentation in Chest X-Ray Images
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作者 Eri Matsuyama 《Journal of Biomedical Science and Engineering》 2021年第6期288-299,共12页
<span style="font-family:Verdana;">Detecting and segmenting the lung regions in chest X-ray images is an important part in artificial intelligence-based computer-aided diagnosis/detection (AI-CAD) syst... <span style="font-family:Verdana;">Detecting and segmenting the lung regions in chest X-ray images is an important part in artificial intelligence-based computer-aided diagnosis/detection (AI-CAD) systems for chest radiography. However, if the chest X-ray images themselves are used as training data for the AI-CAD system, the system might learn the irrelevant image-based information resulting in the decrease of system’s performance. In this study, we propose a lung region segmentation method that can automatically remove the shoulder and scapula regions, mediastinum, and diaphragm regions in advance from various chest X-ray images to be used as learning data. The proposed method consists of three main steps. First, employ the simple linear iterative clustering algorithm, the lazy snapping technique and local entropy filter to generate an entropy map. Second, apply morphological operations to the entropy map to obtain a lung mask. Third, perform automated segmentation of the lung field using the obtained mask. A total of 30 images were used for the experiments. In order to verify the effectiveness of the proposed method, two other texture maps, namely, the maps created from the standard deviation filtering and the range filtering, were used for comparison. As a result, the proposed method using the entropy map was able to appropriately remove the unnecessary regions. In addition, this method was able to remove the markers present in the image, but the other two methods could not. The experimental results have revealed that our proposed method is a highly generalizable and useful algorithm. We believe that this method might act an important role to enhance the performance of AI-CAD systems for chest X-ray images.</span> 展开更多
关键词 Chest X-Ray Image segmentation THRESHOLDING Simple Linear iterative Clustering Lazy Snapping Entropy Filtering MASKING AI-CAD
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MF^(2)ResU-Net:a multi-feature fusion deep learning architecture for retinal blood vessel segmentation
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作者 CUI Zhenchao SONG Shujie QI Jing 《Digital Chinese Medicine》 2022年第4期406-418,共13页
Objective For computer-aided Chinese medical diagnosis and aiming at the problem of insufficient segmentation,a novel multi-level method based on the multi-scale fusion residual neural network(MF2ResU-Net)model is pro... Objective For computer-aided Chinese medical diagnosis and aiming at the problem of insufficient segmentation,a novel multi-level method based on the multi-scale fusion residual neural network(MF2ResU-Net)model is proposed.Methods To obtain refined features of retinal blood vessels,three cascade connected UNet networks are employed.To deal with the problem of difference between the parts of encoder and decoder,in MF2ResU-Net,shortcut connections are used to combine the encoder and decoder layers in the blocks.To refine the feature of segmentation,atrous spatial pyramid pooling(ASPP)is embedded to achieve multi-scale features for the final segmentation networks.Results The MF2ResU-Net was superior to the existing methods on the criteria of sensitivity(Sen),specificity(Spe),accuracy(ACC),and area under curve(AUC),the values of which are 0.8013 and 0.8102,0.9842 and 0.9809,0.9700 and 0.9776,and 0.9797 and 0.9837,respectively for DRIVE and CHASE DB1.The results of experiments demonstrated the effectiveness and robustness of the model in the segmentation of complex curvature and small blood vessels.Conclusion Based on residual connections and multi-feature fusion,the proposed method can obtain accurate segmentation of retinal blood vessels by refining the segmentation features,which can provide another diagnosis method for computer-aided Chinese medical diagnosis. 展开更多
关键词 Medical image processing Atrous space pyramid pooling(ASPP) Residual neural network multi-level model Retinal vessels segmentation
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A novel stepwise thresholding for fuzzy image segmentation
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作者 HE Xiao-hai, LUO Dai-sheng, WU Xiao-qiang, JIANG Li, TENG Qi-zhi, Tao De-yuan Institute of Electronics and Information, Sichuan University, Chengdu 61064, China 《Chinese Journal of Biomedical Engineering(English Edition)》 2001年第1期1-12,共12页
A novel stepwise thresholding method for fuzzy image segmentation is proposed. Unlike the published iterative or recursive thresholding mehtods, this method segments regions into sub-regions iteratively by increasing ... A novel stepwise thresholding method for fuzzy image segmentation is proposed. Unlike the published iterative or recursive thresholding mehtods, this method segments regions into sub-regions iteratively by increasing threshold value in a stepwise manner, based on a preset intensity homogeneity criteria. The method is particularly suited to segmentation of the laser scanning confocal microscopy (LSCM) images, computerised tomography (CT) images, magnetic resonance (MR) images, fingerprint images, etc. The method has been tested on some typical fuzzy image data sets. In this paper, the novel stepwise thresholding is first addressed. Next a new method of region labelling for region extraction is introduced. Then the design of intensity homogeneity segmentation criteria is presented. Some examples of the experiment results of fuzzy image segmentation by the method are given at the end. 展开更多
关键词 FUZZY image IMAGE processing IMAGE segmentation iterative thresholding region labelling intensity HOMOGENEITY
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预制节段拼装梁桥车桥耦合振动分析
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作者 胡佳文 李雪峰 +1 位作者 束晓宇 张智越 《合肥工业大学学报(自然科学版)》 北大核心 2026年第3期378-385,共8页
预制节段拼装结构具有标准化程度高、建设速度快等优势,被应用在越来越多的桥梁上,然而其车桥耦合振动研究较少。文章依据Runge-Kutta法在MATLAB软件中编写考虑随机路面不平整度的1/4车辆模型的求解程序来求解车辆模型,路面不平整度函... 预制节段拼装结构具有标准化程度高、建设速度快等优势,被应用在越来越多的桥梁上,然而其车桥耦合振动研究较少。文章依据Runge-Kutta法在MATLAB软件中编写考虑随机路面不平整度的1/4车辆模型的求解程序来求解车辆模型,路面不平整度函数采用三角级数正弦波叠加模拟,桥梁阻尼采用Rayleigh阻尼;采用约束方程法对胶接缝进行模拟,利用ANSYS求解桥梁模型;再采用全过程迭代法对车桥耦合模型进行求解,以桥梁各跨跨中竖向振动响应为指标,研究路面不平整度、车辆速度、桥梁阻尼比以及胶接缝对预制节段拼装梁桥各跨跨中竖向振动响应的影响。结果表明:预制节段拼装梁桥的车桥耦合振动响应随路面不平整度的增大而增大,随桥梁阻尼比的增大而减小,有无接缝的影响较小;车辆速度对跨中竖向振动的影响会随着车辆位置的变化而改变且不是单调的;车桥力的频率也有不可忽视的影响,且不是单调的。 展开更多
关键词 车桥耦合振动 预制节段 胶接缝 路面不平整度 全过程迭代法
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基于组织处理和非线性扩散滤波的CT图像金属伪影去除
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作者 郭杨艳 孔慧华 +2 位作者 陈平 史颖琴 李锦苗 《CT理论与应用研究(中英文)》 2026年第2期326-335,共10页
金属伪影的存在显著降低了CT图像的清晰度和临床诊断价值,主要表现为图像中出现的条纹状伪影,这些伪影不仅掩盖了重要的组织结构,还严重影响了医生对病变的准确判断。针对这一问题,本文提出一种基于组织处理和非线性扩散滤波的CT图像金... 金属伪影的存在显著降低了CT图像的清晰度和临床诊断价值,主要表现为图像中出现的条纹状伪影,这些伪影不仅掩盖了重要的组织结构,还严重影响了医生对病变的准确判断。针对这一问题,本文提出一种基于组织处理和非线性扩散滤波的CT图像金属伪影去除算法。该算法采用多尺度迭代阈值分割技术精确提取金属区域并生成金属投影轨迹,在投影域中对金属部分进行小波去噪和插值处理,生成初步校正图像。利用组织处理技术修复线性插值导致的骨骼结构缺失,并结合非线性扩散滤波抑制残留伪影,同时有效保留图像边缘细节。实验结果表明,相较于传统方法,该算法能显著降低金属伪影强度,避免二次伪影产生,并保留金属植入物周边的骨骼及软组织结构,提升CT图像的成像质量与临床诊断价值。 展开更多
关键词 金属伪影去除 多尺度迭代阈值分割 组织处理 非线性扩散滤波
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Superpixel-Aware Transformer with Attention-Guided Boundary Refinement for Salient Object Detection
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作者 Burhan Baraklı Can Yüzkollar +1 位作者 Tugrul Ta¸sçı Ibrahim Yıldırım 《Computer Modeling in Engineering & Sciences》 2026年第1期1092-1129,共38页
Salient object detection(SOD)models struggle to simultaneously preserve global structure,maintain sharp object boundaries,and sustain computational efficiency in complex scenes.In this study,we propose SPSALNet,a task... Salient object detection(SOD)models struggle to simultaneously preserve global structure,maintain sharp object boundaries,and sustain computational efficiency in complex scenes.In this study,we propose SPSALNet,a task-driven two-stage(macro–micro)architecture that restructures the SOD process around superpixel representations.In the proposed approach,a“split-and-enhance”principle,introduced to our knowledge for the first time in the SOD literature,hierarchically classifies superpixels and then applies targeted refinement only to ambiguous or error-prone regions.At the macro stage,the image is partitioned into content-adaptive superpixel regions,and each superpixel is represented by a high-dimensional region-level feature vector.These representations define a regional decomposition problem in which superpixels are assigned to three classes:background,object interior,and transition regions.Superpixel tokens interact with a global feature vector from a deep network backbone through a cross-attention module and are projected into an enriched embedding space that jointly encodes local topology and global context.At the micro stage,the model employs a U-Net-based refinement process that allocates computational resources only to ambiguous transition regions.The image and distance–similarity maps derived from superpixels are processed through a dual-encoder pathway.Subsequently,channel-aware fusion blocks adaptively combine information from these two sources,producing sharper and more stable object boundaries.Experimental results show that SPSALNet achieves high accuracy with lower computational cost compared to recent competing methods.On the PASCAL-S and DUT-OMRON datasets,SPSALNet exhibits a clear performance advantage across all key metrics,and it ranks first on accuracy-oriented measures on HKU-IS.On the challenging DUT-OMRON benchmark,SPSALNet reaches a MAE of 0.034.Across all datasets,it preserves object boundaries and regional structure in a stable and competitive manner. 展开更多
关键词 Salient object detection superpixel segmentation TRANSFORMERS attention mechanism multi-level fusion edge-preserving refinement model-driven
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基于动态位移响应的桥梁影响线提取和损伤识别
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作者 姜山 《广州建筑》 2026年第3期68-76,共9页
位移影响线(DIL)是评估桥梁健康的重要指标,但在实际工程应用中,由于车辆荷载的未知性,通常难以从桥梁的动态响应中直接提取并应用于损伤识别。针对这一问题,本文提出了一种结合多段基函数近似与自适应分段迭代拟合的计算框架,用于从桥... 位移影响线(DIL)是评估桥梁健康的重要指标,但在实际工程应用中,由于车辆荷载的未知性,通常难以从桥梁的动态响应中直接提取并应用于损伤识别。针对这一问题,本文提出了一种结合多段基函数近似与自适应分段迭代拟合的计算框架,用于从桥梁动态响应中精确提取位移影响线并实现损伤识别。研究通过多段基函数对DIL进行逼近,并采用自适应分段策略进行迭代计算,从而提取出具有准静态特征的高精度DIL。进一步构建了位移影响线偏差(DDIL)和位移影响线偏差曲率(DCDIL)两项损伤识别指标。数值算例结果表明,该方法提取的DIL与理论值相比,均方根误差(RMSE)为0.0102,验证了提取算法的准确性;在损伤识别方面,DDIL与DCDIL的损伤定位偏差均控制在0.1 m以内,且当损伤程度由20%增至30%时,DCDIL的峰值幅值至少提升了100%,体现了其对损伤程度的显著敏感性。研究验证了所提出方法在等截面简支梁桥和变截面连续梁桥中提取影响线与损伤识别的有效性与准确性。 展开更多
关键词 影响线 多段基函数模型 自适应分段 迭代拟合方法 桥梁损伤识别
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Multi-segment and Multi-ply Overlapping Process of Multi Coupled Activities Based on Valid Information Evolution 被引量:1
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作者 WANG Zhiliang WANG Yunxia QIU Shenghai 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第1期176-188,共13页
Complex product development will inevitably face the design planning of the multi-coupled activities, and overlapping these activities could potentially reduce product development time, but there is a risk of the addi... Complex product development will inevitably face the design planning of the multi-coupled activities, and overlapping these activities could potentially reduce product development time, but there is a risk of the additional cost. Although the downstream task information dependence to the upstream task is already considered in the current researches, but the design process overall iteration caused by the information interdependence between activities is hardly discussed; especially the impact on the design process' overall iteration from the valid information accumulation process. Secondly, most studies only focus on the single overlapping process of two activities, rarely take multi-segment and multi-ply overlapping process of multi coupled activities into account; especially the inherent link between product development time and cost which originates from the overlapping process of multi coupled activities. For the purpose of solving the above problems, as to the insufficiency of the accumulated valid information in overlapping process, the function of the valid information evolution (VIE) degree is constructed. Stochastic process theory is used to describe the design information exchange and the valid information accumulation in the overlapping segment, and then the planning models of the single overlapping segment are built. On these bases, by analyzing overlapping processes and overlapping features of multi-coupling activities, multi-segment and multi-ply overlapping planning models are built; by sorting overlapping processes and analyzing the construction of these planning models, two conclusions are obtained: (1) As to multi-segment and multi-ply overlapping of multi coupled activities, the total decrement of the task set development time is the sum of the time decrement caused by basic overlapping segments, and minus the sum of the time increment caused by multiple overlapping segments; (2) the total increment of development cost is the sum of the cost increment caused by all overlapping process. And then, based on overlapping degree analysis of these planning models, by the V1E degree function, the four lemmas theory proofs are represented, and two propositions are finally proved: (1) The multi-ply overlapping of the multi coupled activities will weaken the basic overlapping effect on the development cycle time reduction (2) Overlapping the multi coupled activities will decrease product development cycle, but increase product development cost. And there is trade-off between development time and cost. And so, two methods are given to slacken and eliminate multi-ply overlapping effects. At last, an example about a vehicle upper subsystem design illustrates the application of the proposed models; compared with a sequential execution pattern, the decreasing of development cycle (22%) and the increasing of development cost (3%) show the validity of the method in the example The proposed research not only lays a theoretical foundation for correctly planning complex product development process, but also provides specific and effective operation methods for overlapping multi coupled activities. 展开更多
关键词 multi coupled activities valid information evolution multi-segment multi-ply overlapping development time and cost trade-ofl iteration
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Symplectic multi-level method for solving nonlinear optimal control problem
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作者 彭海军 高强 +1 位作者 吴志刚 钟万勰 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2010年第10期1251-1260,共10页
By converting an optimal control problem for nonlinear systems to a Hamiltonian system,a symplecitc-preserving method is proposed.The state and costate variables are approximated by the Lagrange polynomial.The state v... By converting an optimal control problem for nonlinear systems to a Hamiltonian system,a symplecitc-preserving method is proposed.The state and costate variables are approximated by the Lagrange polynomial.The state variables at two ends of the time interval are taken as independent variables.Based on the dual variable principle,nonlinear optimal control problems are replaced with nonlinear equations.Furthermore,in the implementation of the symplectic algorithm,based on the 2N algorithm,a multilevel method is proposed.When the time grid is refined from low level to high level,the initial state and costate variables of the nonlinear equations can be obtained from the Lagrange interpolation at the low level grid to improve efficiency.Numerical simulations show the precision and the efficiency of the proposed algorithm in this paper. 展开更多
关键词 nonlinear optimal control dual variable variational principle multi-level iteration symplectic algorithm
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基于分段迭代法的抽水蓄能电站上下水库联合洪水调节计算模型 被引量:2
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作者 方国华 姬新洋 +4 位作者 吴勇拓 李超 郁捷皓 于赛玉 鄢军军 《河海大学学报(自然科学版)》 北大核心 2025年第4期1-9,123,共10页
针对现有抽水蓄能电站洪水调节计算方法大多忽略上下水库水力联动关系,且常简化考虑满发流量与天然洪水叠加情景的问题,提出了一种基于分段迭代法的抽水蓄能电站上下水库联合洪水调节计算模型。该模型构建了能够反映上下水库完整水量交... 针对现有抽水蓄能电站洪水调节计算方法大多忽略上下水库水力联动关系,且常简化考虑满发流量与天然洪水叠加情景的问题,提出了一种基于分段迭代法的抽水蓄能电站上下水库联合洪水调节计算模型。该模型构建了能够反映上下水库完整水量交换与水力耦合关系的数学模型,并采用分段迭代算法对上下水库水位及流量的动态变化过程进行精细化求解;在此基础上,模型结合滑动组合方法构建了洪水遭遇情景矩阵,模拟不同工况和洪水遭遇情景对上下水库运行的影响,并提出了动态预留库容控制策略,以保障电站的安全运行以及后续发电需求。实例验证结果表明:所提出的模型能够准确、稳定地模拟上下水库在复杂洪水情景下的动态响应过程,并有效揭示洪水遭遇时机、电站运行状态以及预留库容控制策略对水库水情变化的关键影响;模型所识别的最不利洪水遭遇情景符合抽水蓄能电站的运行规律,可为抽水蓄能电站的工程设计与安全运行提供科学的参考依据。 展开更多
关键词 抽水蓄能电站 洪水调节 水力联动 预留库容动态控制 分段迭代法
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基于超像素分割的暗通道先验图像去雾算法 被引量:2
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作者 李波 胡红萍 杨正民 《测试技术学报》 2025年第4期415-423,共9页
针对图像去雾过程中暗通道先验算法易受白色物体或明亮区域影响导致大气光和透射率估计不准确等问题,提出了一种基于超像素分割的暗通道先验图像去雾算法。首先,利用简单线性迭代聚类超像素算法对暗通道先验进行改进;其次,对有雾图像利... 针对图像去雾过程中暗通道先验算法易受白色物体或明亮区域影响导致大气光和透射率估计不准确等问题,提出了一种基于超像素分割的暗通道先验图像去雾算法。首先,利用简单线性迭代聚类超像素算法对暗通道先验进行改进;其次,对有雾图像利用改进的暗通道先验进行超像素分割得到超像素块,接着对每一个超像素块求取局部大气光值并取平均值;然后,对粗透射图进行伽马校正,并利用平均梯度值作为权重对粗透射图和校正后的透射图进行权重融合求取最终透射图;最后,利用大气散射模型的逆过程得到去雾图像。实验结果表明,超像素分割解决了暗通道先验算法估计大气光对最亮像素的依赖问题,所提算法能够很好地提高去雾图像的清晰度,保留图像的纹理细节,且效果优于其他比较算法。 展开更多
关键词 暗通道先验 超像素分割 简单线性迭代聚类算法 图像去雾 伽马校正
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