共查询到20条相似文献，搜索用时 171 毫秒
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本文提出了一种基于彩色可见光图像进行户外高压绝缘子污秽等级检测的新方法,该方法首先对绝缘子可见光图像进行预处理,再提取特征值,最后设计分类器实现污秽等级检测。通过110kV变电站现场各污秽等级绝缘子图像样本分析,证实了该方法的有效性。 相似文献
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《黑龙江科技信息》2016,(9)
污秽度和潮湿是影响输电线路绝缘子耐污闪性能的基本因素。潮湿属于不可控因素,因此实时掌握绝缘子表面污秽度的状态对防污闪工作,有针对性地制定清扫计划,保障电网安全运行有重要意义。本文以人工污秽试验为基础,使用XP-70和XWP2-70两种型号绝缘子,着重对比研究了泄漏电流的有效值均值、最大值及标准差三个特征量与绝缘子表面污秽状态的数学关系。主要得出:泄漏电流这三个特征量随着等值盐密的增加均呈上升趋势;以泄漏电流的有效值均值、最大值及标准差三个特征量作为输入变量建立的绝缘子污秽状态人工神经网络输出误差在8%以内;泄漏电流三个特征量与污秽度的相关程度依次为有效值均值、最大值及标准差,该结果可作为确定污闪预警特征量不同权重的依据。 相似文献
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绝缘子污秽闪络和输电线路覆冰对电力系统安全运行有着极大的威胁。文章设计了一套在线监测系统,测量绝缘子表面的泄漏电流与环境温湿度,作为判断绝缘子污秽情况的依据;采集绝缘子及附近线路的图像,作为判断线路覆冰情况的依据。采集到的各种数据通过GPRS模块和短距离无线传输模块以无线方式传输到监控中心。 相似文献
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随着人类对自然环境的资源过份索取,进一步造成气候恶劣变化,大气中污秽混合物对高压输电线路的绝缘子安全稳定运行是一致命威胁,污秽绝缘子泄漏电流发生急剧上升进一步造成飞弧是整个绝缘子串分生闪络的最终结果,本文从绝缘子覆盖污秽物后对电力系统的危害性及污秽绝缘子闪络过程进行全面的分析,其结果对高压输电线路绝缘子安全稳定运行具有一定性参考意义。 相似文献
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目前在实验室进行的人工污秽试验,常常需要先确定绝缘子表面的污层是否达到饱和湿润,而后才能施加电压进行研究。针对绝缘子污层的饱和与否的判断缺少科学定量判断方法的现状,本文通过试验研究了瓷和玻璃绝缘子污层湿润状态与湿润时间的关系;瓷和玻璃绝缘子污层湿润状态与蒸汽雾浓度的关系;瓷和玻璃绝缘子表面污秽量与饱和湿润时间的关系,得出了一些有益的结论,为人工污秽试验的改进提供参考。 相似文献
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合成绝缘子与传统的瓷质绝缘子、钢化玻璃绝缘子比较,具有质量轻,体积小,便于运输及安装,机械强度高,耐污秽生能好,免预防性测试。 相似文献
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输配电线路在特殊气候条件下的安全运行具有重要意义,要做好绝缘子的防污闪、线路防雷及防风工作。户外绝缘子,常年受到工业污秽或自然界盐碱、飞尘的污染,在毛毛雨、雾、或湿度大的天气条件下,绝缘子表面的污秽尘埃被润湿,表面电导剧增,使绝缘子的泄漏电流剧增,其结果使绝缘子在工频和操作冲击电压下的闪络电压(污闪电压)显著降低甚至有可能使绝缘子在工作电压下发生闪络。此外,雷击线路时,自线路入侵的雷电波也是威胁变电所的主要因素。综合考虑技术和经济措施,提高线路的防雷可以提高电网运行可靠性。 相似文献
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绝缘子污闪必要条件是出现潮湿的气候环境,绝缘子上的污秽在毛毛雨、大雾、小雨夹雪等湿润的条件下易形成导电通道,致使泄漏电流增大直至发生闪络.本文主要对输电线路的污闪及影响因素进行分析. 相似文献
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Many of the approaches to image retrieval on the Web have their basis in text retrieval. However, when searchers are asked to describe their image needs, the resulting query is often short and potentially ambiguous. The solution we propose is to perform automatic query expansion using Wikipedia as the source knowledge base, resulting in a diversification of the search results. The outcome is a broad range of images that represent the various possible interpretations of the query. In order to assist the searcher in finding images that match their specific intentions for the query, we have developed an image organization method that uses both the conceptual information associated with each image, and the visual features extracted from the images. This, coupled with a hierarchical organization of the concepts, provides an interactive interface that takes advantage of the searchers’ abilities to recognize relevant concepts, filter and focus the search results based on these concepts, and visually identify relevant images while navigating within the image space. In this paper, we outline the key features of our image retrieval system (CIDER), and present the results of a preliminary user evaluation. The results of this study illustrate the potential benefits that CIDER can provide for searchers conducting image retrieval tasks. 相似文献
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基于PCA及SVM的图像信息隐藏检测* 总被引：1，自引：0，他引：1
本文提出了一种基于主成分分析（PCA, principal components analysis）及支持向量机（SVM, support vector machines）的信息隐藏盲检测方法。该方法根据信息隐藏时对载体图像引入噪声的特点,通过分析图像块的主成分,计算出图像的特征向量。通过对原始样本图像和藏密样本图像特征向量的学习和训练,得到SVM检测模型,可用于信息隐藏的盲检测。实验结果表明,该方法能够有效地检测出目前常用的信息隐藏方法。 相似文献
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In this paper, we have proposed a robust super-resolution high-frequency component estimation (RS-HFCE) method, which can efficiently estimate lost high-frequency components and correct aliasing effects of low-frequency components of an image. The fundamental principle of operation of the proposed method is based on the idea that, when a baseband band-limited image signal of known bandwidth in a high-resolution lattice is iteratively low-pass filtered in the frequency domain, the unknown values in the lattice can be interpolated, thus correcting the aliasing for the low-frequency components. If this process is done along with adjusting the amplitudes of the known pixel values, some high-frequency components of an image are automatically extrapolated. In order to provide simultaneous edge preservation and noise removal capabilities of the super-resolved images, an improved version of an adaptive Perona–Malik (PM) model is incorporated into the process. One of the characteristics of the proposed method is its high level of tolerance capabilities to reconstruction errors and noise caused by an increase in the reconstruction scaling factors. High quality images of higher resolution are still appreciably reconstructed when greater magnification factors are used. From a couple of experiments on real images, and using both subjective and objective image quality assessment measures, it is demonstrated that the proposed method outperforms most of other classical methods. 相似文献
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Fatim Zahra Ait Bella Mohammed El Rhabi Abdelilah Hakim Amine Laghrib 《Journal of The Franklin Institute》2018,355(16):8225-8244
In this paper, we investigate two new reflectance and illumination decomposition models based on a nonlocal partial differential equation (PDE) applied to text images. Taking into consideration the higher regularity level of the illumination compared to the reflectance, we propose a nonlocal PDE which deals with repetitive structures and textures that characterize the text image much better compared to the classical local PDEs. The aim of this approach is to use the repetitive features of the reflectance to efficiently extract it from the non-uniform illumination. This idea is motivated by extending the range of application of the nonlocal operators to such a problem. Numerical experiments on both grayscale and color text images show the performance and strength of the proposed nonlocal PDE. 相似文献
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Traditional content based image retrieval attempts to retrieve images using syntactic features for a query image. Annotated image banks and Google allow the use of text to retrieve images. In this paper, we studied the task of using the content of an image to retrieve information in general. We describe the significance of object identification in an information retrieval paradigm that uses image set as intermediate means in indexing and matching. We also describe a unique Singapore Tourist Object Identification Collection with associated queries and relevance judgments for evaluating the new task and the need for efficient image matching using simple image features. We present comprehensive experimental evaluation on the effects of feature dimensions, context, spatial weightings, coverage of image indexes, and query devices on task performance. Lastly we describe the current system developed to support mobile image-based tourist information retrieval. 相似文献
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使用Photoshop软件处理图像时,更多的时候是对图像的一部分而非全部进行处理。在这种情况下,就要把需要处理的图像部分与不需要处理的图像部分区分开来,也就是要在需要处理的图像部分上创建选区。 相似文献
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Content-based image retrieval for medical images is a primary technique for computer-aided diagnosis. While it is a premise for computer-aided diagnosis system to build an efficient medical image database which is paid less attention than that it deserves. In this paper, we provide an efficient approach to develop the archives of large brain CT medical data. Medical images are securely acquired along with relevant diagnosis reports and then cleansed, validated and enhanced. Then some sophisticated image processing algorithms including image normalization and registration are applied to make sure that only corresponding anatomy regions could be compared in image matching. A vector of features is extracted by non-negative tensor factorization and associated with each image, which is essential for the content-based image retrieval. Our experiments prove the efficiency and promising prospect of this database building method for computer-aided diagnosis system. The brain CT image database we built could provide radiologists with a convenient access to retrieve pre-diagnosed, validated and highly relevant examples based on image content and obtain computer-aided diagnosis. 相似文献