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一种复杂背景下的多策略MSVI-CFAR检测算法
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作者 曾献芳 刘聪 +1 位作者 杨作宾 钱锋 《火力与指挥控制》 北大核心 2025年第7期161-167,共7页
为了进一步提高复杂背景下雷达目标恒虚警(CFAR)检测能力,提出了一种基于SVI-CFAR的改进型多策略CFAR(MSVI-CFAR)检测器。该检测器能够估计参考窗口中的杂波背景,并从单元平均CFAR(CA-CFAR)、最大CFAR(GO-CFAR)、开关型CFAR(S-CFAR)和... 为了进一步提高复杂背景下雷达目标恒虚警(CFAR)检测能力,提出了一种基于SVI-CFAR的改进型多策略CFAR(MSVI-CFAR)检测器。该检测器能够估计参考窗口中的杂波背景,并从单元平均CFAR(CA-CFAR)、最大CFAR(GO-CFAR)、开关型CFAR(S-CFAR)和有序统计与单元平均CFAR(OSCA-CFAR)中自适应选择最优检测策略。实验结果表明,MSVI-CFAR在均匀背景、杂波边缘和多目标干扰背景下保持着良好的鲁棒性,并且相对于SVI-CFAR具有更小的CFAR损失和更强的抗多目标干扰性能。 展开更多
关键词 恒虚警检测 多策略恒虚警检测 自适应检测 复杂环境
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SDH-DETR轻量化绝缘子缺陷检测算法
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作者 周景 刘心 +1 位作者 唐振洋 董晖 《电子测量技术》 北大核心 2025年第11期88-104,共17页
为解决无人机在输电线路绝缘子巡检中目标检测算法面临的模型复杂度高、小目标缺陷检测精度不足和上下采样过程中容易造成特征丢失等挑战,本文提出了一种基于轻量化改进的RT-DETR绝缘子缺陷检测算法(SDH-DETR)。首先,以RT-DETR作为基线... 为解决无人机在输电线路绝缘子巡检中目标检测算法面临的模型复杂度高、小目标缺陷检测精度不足和上下采样过程中容易造成特征丢失等挑战,本文提出了一种基于轻量化改进的RT-DETR绝缘子缺陷检测算法(SDH-DETR)。首先,以RT-DETR作为基线算法,降低优化难度并提高鲁棒性;其次,采用轻量级StarNet作为主干网络,在显著降低模型复杂度的同时提升特征提取能力;接着,引入DySample动态上采样模块,通过基于采样点的自适应上采样方法,有效减少细节丢失与图像失真;最后,利用Harr小波变换下采样模块(HWD),实现低频与高频信息的高效融合,抑制复杂背景干扰并增强对小目标的检测能力。在复杂背景数据集上的验证实验表明,SDH-DETR的平均精度达98.5%,较基线算法提升0.9%,参数量和计算量分别减少43%和46.1%,检测速度达78.6 fps。这表明该算法在保证高准确性的同时,实现了轻量化设计,满足了输电线路巡检对效率和性能的实际需求。 展开更多
关键词 输电线路 目标检测 绝缘子缺陷检测 复杂背景 轻量化 RT-DETR算法
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Real-time moving object detection for video monitoring systems 被引量:18
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作者 Wei Zhiqiang Ji Xiaopeng Wang Peng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第4期731-736,共6页
Moving object detection is one of the challenging problems in video monitoring systems, especially when the illumination changes and shadow exists. Amethod for real-time moving object detection is described. Anew back... Moving object detection is one of the challenging problems in video monitoring systems, especially when the illumination changes and shadow exists. Amethod for real-time moving object detection is described. Anew background model is proposed to handle the illumination varition problem. With optical flow technology and background subtraction, a moving object is extracted quickly and accurately. An effective shadow elimination algorithm based on color features is used to refine the moving obj ects. Experimental results demonstrate that the proposed method can update the background exactly and quickly along with the varition of illumination, and the shadow can be eliminated effectively. The proposed algorithm is a real-time one which the foundation for further object recognition and understanding of video mum'toting systems. 展开更多
关键词 video monitoring system moving object detection background subtraction background model shadow elimination.
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Patch-based vehicle logo detection with patch intensity and weight matrix 被引量:3
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作者 刘海明 黄樟灿 Ahmed Mahgoub Ahmed Talab 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第12期4679-4686,共8页
A patch-based method for detecting vehicle logos using prior knowledge is proposed.By representing the coarse region of the logo with the weight matrix of patch intensity and position,the proposed method is robust to ... A patch-based method for detecting vehicle logos using prior knowledge is proposed.By representing the coarse region of the logo with the weight matrix of patch intensity and position,the proposed method is robust to bad and complex environmental conditions.The bounding-box of the logo is extracted by a thershloding approach.Experimental results show that 93.58% location accuracy is achieved with 1100 images under various environmental conditions,indicating that the proposed method is effective and suitable for the location of vehicle logo in practical applications. 展开更多
关键词 vehicle logo detection prior knowledge gradient extraction patch intensity weight matrix background removing
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Moving target detection based on improved ghost suppression and adaptive visual background extraction 被引量:9
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作者 LIU Ling CHAI Guo-hua QU Zhong 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第3期747-759,共13页
Visual background extraction algorithm(ViBe)uses the first frame image to initialize the background model,which can easily introduce the“ghost”.Because ViBe uses the fixed segmentation threshold to achieve the foreg... Visual background extraction algorithm(ViBe)uses the first frame image to initialize the background model,which can easily introduce the“ghost”.Because ViBe uses the fixed segmentation threshold to achieve the foreground and background segmentation,the detection results in many false detections for the highly dynamic background.To solve these problems,an improved ghost suppression and adaptive Visual Background Extraction algorithm is proposed in this paper.Firstly,with the pixel’s temporal and spatial information,the historical pixels of a certain combination are used to initialize the background model in the odd frames of the video sequence.Secondly,the background sample set combined with the neighborhood pixels are used to determine a complex degree of the background,to acquire the adaptive segmentation threshold.Thirdly,the update rate is adjusted based on the complexity of the background.Finally,the detected result goes through a post-processing to achieve better detection results.The experimental results show that the improved algorithm will not only quickly suppress the“ghost”,but also have a better detection in a complex dynamic background. 展开更多
关键词 moving target detection ghost suppression adaptive visual background extraction
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A background refinement method based on local density for hyperspectral anomaly detection 被引量:5
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作者 ZHAO Chun-hui WANG Xin-peng +1 位作者 YAO Xi-feng TIAN Ming-hua 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第1期84-94,共11页
For anomaly detection,anomalies existing in the background will affect the detection performance.Accordingly,a background refinement method based on the local density is proposed to remove the anomalies from thebackgr... For anomaly detection,anomalies existing in the background will affect the detection performance.Accordingly,a background refinement method based on the local density is proposed to remove the anomalies from thebackground.In this work,the local density is measured by its spectral neighbors through a certain radius which is obtained by calculating the mean median of the distance matrix.Further,a two-step segmentation strategy is designed.The first segmentation step divides the original background into two subsets,a large subset composed by background pixels and a small subset containing both background pixels and anomalies.The second segmentation step employing Otsu method with an aim to obtain a discrimination threshold is conducted on the small subset.Then the pixels whose local densities are lower than the threshold are removed.Finally,to validate the effectiveness of the proposed method,it combines Reed-Xiaoli detector and collaborative-representation-based detector to detect anomalies.Experiments are conducted on two real hyperspectral datasets.Results show that the proposed method achieves better detection performance. 展开更多
关键词 hyperspectral imagery anomaly detection background refinement the local density
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Moving object detection method based on complementary multi resolution background models 被引量:2
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作者 屠礼芬 仲思东 彭祺 《Journal of Central South University》 SCIE EI CAS 2014年第6期2306-2314,共9页
A novel moving object detection method was proposed in order to adapt the difficulties caused by intermittent object motion,thermal and dynamic background sequences.Two groups of complementary Gaussian mixture models ... A novel moving object detection method was proposed in order to adapt the difficulties caused by intermittent object motion,thermal and dynamic background sequences.Two groups of complementary Gaussian mixture models were used.The ghost and real static object could be classified by comparing the similarity of the edge images further.In each group,the multi resolution Gaussian mixture models were used and dual thresholds were applied in every resolution in order to get a complete object mask without much noise.The computational color model was also used to depress illustration variations and light shadows.The proposed method was verified by the public test sequences provided by the IEEE Change Detection Workshop and compared with three state-of-the-art methods.Experimental results demonstrate that the proposed method is better than others for all of the evaluation parameters in intermittent object motion sequences.Four and two in the seven evaluation parameters are better than the others in thermal and dynamic background sequences,respectively.The proposed method shows a relatively good performance,especially for the intermittent object motion sequences. 展开更多
关键词 moving object detection complementary Gaussian mixture models intermittent object motion thermal and dynamic background
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改进RT-DETR的小目标检测方法研究
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作者 程鑫淼 张雪松 +1 位作者 曹冰洁 宋存利 《计算机工程与应用》 北大核心 2025年第15期144-155,共12页
针对复杂场景小目标检测中存在的背景干扰严重、特征表达能力不足等问题,提出了一种基于改进RT-DETR的小目标检测模型DA-DETR。在骨干网络中引入了一种多阶门控聚合模块(multi-order gated aggregation block),通过增强局部与全局特征... 针对复杂场景小目标检测中存在的背景干扰严重、特征表达能力不足等问题,提出了一种基于改进RT-DETR的小目标检测模型DA-DETR。在骨干网络中引入了一种多阶门控聚合模块(multi-order gated aggregation block),通过增强局部与全局特征的差异性使目标检测器能更好地区分前景物体和嘈杂背景。引入了卷积加性标记混合器(convolutional additive token mixer,CATM),进一步减少了特征丢失,提升了模型的全局与局部信息整合能力。提出了一种改进的损失函数CoreProximity-IoU,其对于小目标检测的IoU变化更敏感。实验结果表明,DA-DETR模型在VisDrone2019数据集上的mAP@50和mAP@50:95分别提升了2.8和2.3个百分点,在KITTI数据集上的mAP@50和mAP@50:95分别比RT-DETR提升了0.6和0.4个百分点。此外,模型计算量和参数量均有显著的减少,进一步验证了所提出方法的有效性和优越性。 展开更多
关键词 小目标检测 RT-DETR 复杂场景 背景干扰
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Two-channel model based adaptive schlieren detection algorithm for BOS system
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作者 LIU Han ZHANG Yanmei +2 位作者 ZHAO Baojun GUO Haichao ZHAO Boya 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第2期251-258,共8页
A schlieren detection algorithm is proposed for the ground-to-air background oriented schlieren(BOS) system to achieve high-speed airplane shock waves visualization. The proposed method consists of three steps. Firstl... A schlieren detection algorithm is proposed for the ground-to-air background oriented schlieren(BOS) system to achieve high-speed airplane shock waves visualization. The proposed method consists of three steps. Firstly, image registration is incorporated for reducing errors caused by the camera motion.Then, the background subtraction dual-model single Gaussian model(BS-DSGM) is proposed to build a precise background model. The BS-DSGM could prevent the background model from being contaminated by the shock waves. Finally, the twodimensional orthogonal discrete wavelet transformation is used to extract schlieren information and averaging schlieren data. Experimental results show our proposed algorithm is able to detect the aircraft in-flight and to extract the schlieren information. The precision of schlieren detection algorithm is 0.96. Three image quality evaluation indices are chosen for quantitative analysis of the shock waves visualization. The white Gaussian noise is added in the frames to validate the robustness of the proposed algorithm.Moreover, we adopt two times and four times down sampling to simulate different imaging distances for revealing how the imaging distance affects the schlieren information in the BOS system. 展开更多
关键词 background model background ORIENTED SCHLIEREN (BOS) SCHLIEREN detection WAVELET DECOMPOSITION
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Real-time detection of moving objects in video sequences
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作者 宋红 石峰 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2005年第3期687-691,共5页
An approach to detection of moving objects in video sequences, with application to video surveillance is presented. The algorithm combines two kinds of change points, which are detected from the region-based frame dif... An approach to detection of moving objects in video sequences, with application to video surveillance is presented. The algorithm combines two kinds of change points, which are detected from the region-based frame difference and adjusted background subtraction. An adaptive threshold technique is employed to automatically choose the threshold value to segment the moving objects from the still background. And experiment results show that the algorithm is effective and efficient in practical situations. Furthermore, the algorithm is robust to the effects of the changing of lighting condition and can be applied for video surveillance system. 展开更多
关键词 object detection video surveillance region-based frame difference adjusted background subtraction.
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基于YOLOv10-MHSA的“三北”工程内蒙古地区植树位点精准检测研究
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作者 谢纪元 张东彦 +3 位作者 牛圳 程涛 苑峰 刘亚玲 《智慧农业(中英文)》 2025年第3期108-119,共12页
[目的/意义]为解决无人机平台下“三北”工程内蒙古地区植树位点(树坑)受复杂背景(灌木、杂草群、裸露沙土、起伏地形等)影响,容易出现树坑漏检错检问题,构建了一种针对该场景下的小目标检测模型——YOLOv10-MHSA(You Only Look Once ve... [目的/意义]为解决无人机平台下“三北”工程内蒙古地区植树位点(树坑)受复杂背景(灌木、杂草群、裸露沙土、起伏地形等)影响,容易出现树坑漏检错检问题,构建了一种针对该场景下的小目标检测模型——YOLOv10-MHSA(You Only Look Once version 10-Multi-head Self-Attention)。[方法]以YOLOv10为基准模型,采用分层特征增强策略,通过跨层信息补偿提升小目标语义表征的完整性,提高其对小目标特征描述的准确性;引入可变卷积核AKConv(Adaptive Kernel Convolution),使模型更精确地聚焦输入图像的特征;构建融合特征的多头自注意力机制MHSA以实现考虑复杂环境因素的有效特征获取;引入Focal-EIOU Loss(Focal Efficient Inter-section over Union Loss)替代原有CIOU Loss(Complete Intersection over Union Loss)作为边界框的回归损失,构建非线性优化策略,在保证训练稳定性的同时实现边界框参数的精确计算;最后,选择影响精准识别效果最大的两个因素,通过设计多尺度空间分布与光照强度梯度变化的对比实验,系统性验证了模型在复杂场景下的泛化性与鲁棒性。[结果和讨论]提出的模型YOLOv10-MHSA在实验数据集上的平均识别精度和检测准确率分别达96.1%和92.1%,相比原模型分别提高4.1%和5.1%,可满足无人机对“三北”工程内蒙古地区植树位点(树坑)进行实时识别的精度和速度要求。[结论]YOLOv10-MHSA模型通过引入动态特征增强模块,在维持原有检测效率的基础上,成功解决了复杂场景中植树位点小目标特征易湮没的检测瓶颈,这为无人机平台下“三北”工程内蒙古地区植树位点的遥感精准、快速检测提供了新方法。 展开更多
关键词 植树位点 复杂背景 无人机 小目标检测 YOLOv10
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复杂背景下基于YOLOv7-tiny的图像目标检测算法 被引量:9
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作者 薛珊 安宏宇 +1 位作者 吕琼莹 曹国华 《红外与激光工程》 EI CSCD 北大核心 2024年第1期261-272,共12页
“黑飞”无人机一旦带有炸弹等物品,会对人们带来威胁。对在公园、游乐场、学校等复杂背景下“黑飞”的无人机进行目标检测是十分必要的。前沿算法YOLOv7-tiny属于轻量级网络,具有更小的网络结构和参数,更适合检测小目标,但在识别小目... “黑飞”无人机一旦带有炸弹等物品,会对人们带来威胁。对在公园、游乐场、学校等复杂背景下“黑飞”的无人机进行目标检测是十分必要的。前沿算法YOLOv7-tiny属于轻量级网络,具有更小的网络结构和参数,更适合检测小目标,但在识别小目标无人机时出现特征提取能力弱、回归损失大、检测精度低的问题;针对此问题,提出了一种基于YOLOv7-tiny改进的无人机图像目标检测算法YOLOv7-drone。首先,建立无人机图像数据集;其次,设计一种新的注意力机制模块SMSE嵌入到特征提取网络中,增强对复杂背景下无人机目标的关注度;然后,在主干网络中融入RFB结构,扩大特征层的感受野,丰富特征信息以增强特征提取的鲁棒性;然后,改进网络中的特征融合机制,通过新增小目标检测层,增加对小尺度目标的检测精度;然后,改变损失函数提高模型的收敛速度,减少损失以增强模型的鲁棒性;最后,引入可变形卷积(Deformable convolution, DCN),更好的根据目标本身形状进行特征提取,提升了检测精度。在PASCAL VOC公共数据集上进行对比实验,结果表明改进后的算法YOLO7-drone相比于YOLOv7-tiny,平均精度(map@0.5)提升了6%;在自制无人机数据集上进行实验,结果表明YOLOv7-drone与原算法相比,平均精度(map@0.5)提高了6.1%,并且检测速度为72帧/s;与YOLOv5l、YOLOv7目标检测算法进行对比实验,结果表明改进后的算法在平均精度(map@0.5)上分别高于对比算法4%、3.1%,验证了文中算法的可行性。 展开更多
关键词 目标检测 复杂背景 注意力机制 小目标检测
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An algorithm for moving target detection in IR image based on grayscale distribution and kernel function 被引量:6
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作者 王鲁平 张路平 +1 位作者 赵明 李飚 《Journal of Central South University》 SCIE EI CAS 2014年第11期4270-4278,共9页
A fast algorithm based on the grayscale distribution of infrared target and the weighted kernel function was proposed for the moving target detection(MTD) in dynamic scene of image series. This algorithm is used to de... A fast algorithm based on the grayscale distribution of infrared target and the weighted kernel function was proposed for the moving target detection(MTD) in dynamic scene of image series. This algorithm is used to deal with issues like the large computational complexity, the fluctuation of grayscale, and the noise in infrared images. Four characteristic points were selected by analyzing the grayscale distribution in infrared image, of which the series was quickly matched with an affine transformation model. The image was then divided into 32×32 squares and the gray-weighted kernel(GWK) for each square was calculated. At last, the MTD was carried out according to the variation of the four GWKs. The results indicate that the MTD can be achieved in real time using the algorithm with the fluctuations of grayscale and noise can be effectively suppressed. The detection probability is greater than 90% with the false alarm rate lower than 5% when the calculation time is less than 40 ms. 展开更多
关键词 moving target detection gray-weighted kernel function dynamic background
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Vehicle detection algorithm based on codebook and local binary patterns algorithms 被引量:1
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作者 许雪梅 周立超 +1 位作者 墨芹 郭巧云 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第2期593-600,共8页
Detecting the moving vehicles in jittering traffic scenes is a very difficult problem because of the complex environment.Only by the color features of the pixel or only by the texture features of image cannot establis... Detecting the moving vehicles in jittering traffic scenes is a very difficult problem because of the complex environment.Only by the color features of the pixel or only by the texture features of image cannot establish a suitable background model for the moving vehicles. In order to solve this problem, the Gaussian pyramid layered algorithm is proposed, combining with the advantages of the Codebook algorithm and the Local binary patterns(LBP) algorithm. Firstly, the image pyramid is established to eliminate the noises generated by the camera shake. Then, codebook model and LBP model are constructed on the low-resolution level and the high-resolution level of Gaussian pyramid, respectively. At last, the final test results are obtained through a set of operations according to the spatial relations of pixels. The experimental results show that this algorithm can not only eliminate the noises effectively, but also save the calculating time with high detection sensitivity and high detection accuracy. 展开更多
关键词 background modeling Gaussian pyramid CODEBOOK Local binary patterns(LBP) moving vehicle detection
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Dim Moving Small Target Detection by Local and Global Variance Filtering on Temporal Profiles in Infrared Sequences
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作者 Chen Hao Liu Delian 《航空兵器》 CSCD 北大核心 2019年第6期43-49,共7页
In this paper, the temporal different characteristics between the target and background pixels are used to detect dim moving targets in the slow-evolving complex background. A local and global variance filter on tempo... In this paper, the temporal different characteristics between the target and background pixels are used to detect dim moving targets in the slow-evolving complex background. A local and global variance filter on temporal profiles is presented that addresses the temporal characteristics of the target and background pixels to eliminate the large variation of background temporal profiles. Firstly, the temporal behaviors of different types of image pixels of practical infrared scenes are analyzed.Then, the new local and global variance filter is proposed. The baseline of the fluctuation level of background temporal profiles is obtained by using the local and global variance filter. The height of the target pulse signal is extracted by subtracting the baseline from the original temporal profiles. Finally, a new target detection criterion is designed. The proposed method is applied to detect dim and small targets in practical infrared sequence images. The experimental results show that the proposed algorithm has good detection performance for dim moving small targets in the complex background. 展开更多
关键词 small target detection infrared image sequences complex background temporal profile variance filtering
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基于YOLOv5s-AntiUAV的反无人机目标检测算法研究 被引量:9
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作者 谭亮 赵良军 +1 位作者 郑莉萍 肖波 《电光与控制》 CSCD 北大核心 2024年第5期40-45,107,共7页
随着无人机的应用领域不断拓展,无人机的“黑飞”给公共安全造成严重损害。为解决侵入式无人机小目标在复杂飞行环境下的错检和漏检问题,提出基于YOLOv5s-AntiUAV的反无人机目标检测算法。首先,引入结合深度超参数卷积的Slim-Neck范式,... 随着无人机的应用领域不断拓展,无人机的“黑飞”给公共安全造成严重损害。为解决侵入式无人机小目标在复杂飞行环境下的错检和漏检问题,提出基于YOLOv5s-AntiUAV的反无人机目标检测算法。首先,引入结合深度超参数卷积的Slim-Neck范式,增强算法特征提取能力并保持计算效率。其次,在骨干和颈部网络引入SPD-Conv模块,提高在低分辨率图像中小目标的检测性能。最后,用Alpha-CIoU替换YOLOv5s算法中的CIoU,增强算法泛用性。YOLOv5s-AntiUAV算法与YOLOv5s、SSD和Faster R-CNN算法在数据集Anti-UAV上的对比实验结果表明,改进算法的mAP@0.5值分别增长了1.1、12.1和4.9个百分点,凸显其实用性。由在VisDrone2019数据集上进行的迁移实验显示,相较于YOLOv5s算法,改进算法mAP@0.5值提升了4.5个百分点,表明其相较于原算法具有更强的鲁棒性。 展开更多
关键词 反无人机算法 小目标检测 YOLOv5s 复杂背景 Alpha-CIoU
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联合全局注意力的自然环境下草莓果实检测算法研究
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作者 秦培亮 秦昌友 +2 位作者 王晓拓 刘勇 梁正龙 《中国农机化学报》 北大核心 2025年第9期91-96,103,共7页
为克服草莓采摘机器在作业过程中存在采摘点定位精度低、遮挡草莓识别困难以及复杂背景干扰等问题,对现有的YOLOv5检测模型进行改进,通过引入全局注意力机制(GAM),增强模型对全局特征感知能力,更专注于草莓显著特征,减少误检同时提升对... 为克服草莓采摘机器在作业过程中存在采摘点定位精度低、遮挡草莓识别困难以及复杂背景干扰等问题,对现有的YOLOv5检测模型进行改进,通过引入全局注意力机制(GAM),增强模型对全局特征感知能力,更专注于草莓显著特征,减少误检同时提升对小目标特征提取和强化被遮挡区域特征,旨在提升模型自然环境背景下草莓果实定位准确率和遮挡识别的预测精确率;优化损失函数,使用软交并比(SIoU)作为损失函数,以增强尺度不变性和角度敏感性,确保正负样本的有效平衡。试验结果显示,相比于原始模型,经过改进后的模型在草莓果实检测精确率、召回率、平均精度、平均精度均值上分别提高2.20%、5.78%、5.11%、3.11%,在与SSD、YOLOv5s、YOLOv5m、YOLOv7—tiny、YOLOv8n以及YOLOv9c的对比试验中,在各项指标上均有很大优势,具有强鲁棒性,为机器人精准采摘的实现提供重要的技术支撑。 展开更多
关键词 草莓果实 深度学习 YOLOv5s 目标检测 复杂背景
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基于特征频次谐波电压的孤岛检测方法
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作者 高淑萍 郭芳宾 +2 位作者 宋国兵 李晓芳 蔚坤 《太阳能学报》 北大核心 2025年第3期254-262,共9页
当分布式电源与主电网失去连接时应切断对本地负荷的供电,为迅速可靠地检测到这种状态,保证系统安全稳定运行,以三相分布式电源并网逆变器的孤岛检测技术为研究对象,提出一种基于分布式发电(DG)侧和电网侧特征频次谐波电压的被动式孤岛... 当分布式电源与主电网失去连接时应切断对本地负荷的供电,为迅速可靠地检测到这种状态,保证系统安全稳定运行,以三相分布式电源并网逆变器的孤岛检测技术为研究对象,提出一种基于分布式发电(DG)侧和电网侧特征频次谐波电压的被动式孤岛检测新方法。首先,对公共连接点处两侧谐波责任进行划分,根据谐波责任划分结果选取两侧对公共连接点处谐波电压影响最大的特征频次谐波用于孤岛检测并给出整定判据。其次,对孤岛前后公共连接点处谐波电压比值的理论值进行推导,当孤岛前后两侧特征频次谐波电压参数的变化都超过整定阈值时则判断发生孤岛。最后,根据IEEE Std.1547.1孤岛检测标准对所提方法进行验证。仿真结果表明,该方法可快速、准确、有效地检测出孤岛。该方法采用双重判据可减少误判的可能性、提高孤岛检测的可靠性,与传统基于谐波域的被动式孤岛检测方法相比,该方法可避免检测频次谐波困难、阈值难以确定、受背景谐波影响的问题。 展开更多
关键词 可再生能源 分布式发电 阈值电压 孤岛检测 谐波责任 背景谐波
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基于FPGA的PCB缺陷检测系统设计与实现
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作者 任喜伟 刘嘉玥 +1 位作者 余杰 孙悦 《仪表技术与传感器》 北大核心 2025年第3期58-64,71,共8页
为应对传统印刷电路板(PCB)缺陷检测方法存在的检测速度慢、准确率低等问题,设计了基于FPGA的PCB缺陷检测系统。系统采用CMOS OV5640传感器采集PCB图像数据,并对采集的图像进行灰度化、滤波及边缘检测等图像预处理。提出了改进的灰度拉... 为应对传统印刷电路板(PCB)缺陷检测方法存在的检测速度慢、准确率低等问题,设计了基于FPGA的PCB缺陷检测系统。系统采用CMOS OV5640传感器采集PCB图像数据,并对采集的图像进行灰度化、滤波及边缘检测等图像预处理。提出了改进的灰度拉伸算法,通过整体线性拉伸灰度值,图像对比度显著增强;提出了改进的边缘检测算法,扩展传统Sobel边缘检测2算子至8算子边缘检测,提高图像边缘信息的清晰度,增强图像分析与识别的准确性。系统将预处理后的PCB图像和标准模板图像存储在SDRAM中,采用背景差分比算法进行缺陷检测,并选用EP4CE10F17C8N芯片实现系统各模块的FPGA设计。实验结果表明:改进的检测系统在检测精度方面较其他方法显著提升,且相比于PCB缺陷检测软件,FPGA硬件处理速度明显提高。 展开更多
关键词 图像处理 FPGA 背景差分算法 缺陷检测
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新工科背景下OBE理念在“食品无损检测技术”课程中的应用
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作者 申婷婷 翟晓东 +4 位作者 黄晓玮 张柔佳 李志华 石吉勇 邹小波 《农产品加工》 2025年第6期133-135,139,共4页
食品无损检测是保证食品品质与安全检测重要的技术支撑,该技术方面的人才培养对于食品行业质量监督、新型装备研发具有重要意义,是新工科建设与发展背景下高校食品教育工作的重要任务之一。Outcomes-based education(OBE)理念以明确的... 食品无损检测是保证食品品质与安全检测重要的技术支撑,该技术方面的人才培养对于食品行业质量监督、新型装备研发具有重要意义,是新工科建设与发展背景下高校食品教育工作的重要任务之一。Outcomes-based education(OBE)理念以明确的学习成果为导向,以学生为中心,结合持续评估和反馈,促使学生通过课程在知识和技能方面取得实质性积累。基于此,提出将OBE理念应用于“食品无损检测技术”课程,具体涉及课程目标、教学过程、考核机制等方面的实施和改进,以期为其他课程的教学改革提供借鉴。 展开更多
关键词 食品无损检测技术 OBE理念 新工科背景 教学改革 食品品质与安全
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