排序方式: 共有86条查询结果,搜索用时 15 毫秒
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传统的支持向量机分类算法对训练样本数目敏感且不具备增量学习的能力,而空间目标识别的工程应用需要积累样本进行大样本的增量学习。根据样本在特征空间分布,提取几何意义上边缘的样本点,成功约减了应用于支持向量机学习的基于雷达散射截面统计特征的训练样本集。利用中心距离比和特征空间多维高斯分布特性,分别提取两类边界样本集和单类边缘样本集;再采用直推式实验设计方法再采样,根据样本潜在结构分布信息选择最能代表样本集结构分布的高价值样本。实验结果表明:样本初选算法能够在有效约减样本集规模的同时保持支持向量机训练分类的精度。 相似文献
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《Journal of the European Ceramic Society》2020,40(11):3788-3794
To enhance the understanding of matrix cracking and damage progression on the macroscopic scale, within a 0/90° fibre reinforced SiCf/SiC ceramic matrix composite (CMC), X-ray computed tomography (XCT) imaging and analysis have been performed in conjunction with a commercially available in-situ mechanical loading device. CMC test coupons were subjected to tensile cyclic loads and inspected using XCT without removal from the tensile loading device. Attempts to measure and quantify the resulting damage using volumetric image analysis techniques are presented, by characterising the crack network from XCT images acquired at both the maximum and minimum load condition during selected fatigue cycles. The XCT detection of significant crack development within the first loading half-cycle shows good agreement with cumulative acoustic emission energy data recorded under similar test conditions. The results are seen as an important step towards correlating the damage behaviour detected via different NDE and health monitoring techniques. 相似文献
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针对多波段融合图像存在对比度低、显著目标不突出的问题,本文提出了一种基于显著性的多波段图像同步融合方法。首先,近红外图像被用来作为数据保真项,红外图像和可见光图像分别为融合结果提供红外显著信息和细节信息;其次,基于视觉显著的红外显著区域提取方法被用来构造权重图,以克服融合结果显著区域不突出和边缘模糊问题;最后,采用交替方向乘子法(alternating direction method of multipliers, ADMM)来求解模型,得到融合结果。研究结果表明,较于代表性图像融合算法,所提算法能在保留红外图像热辐射信息的同时,保有较好的清晰细节,并在多项客观评价指标上优于代表性算法。 相似文献
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Existing multi-channel Medium Access Control (MAC) protocols have been demonstrated to significantly increase wireless network performance compared to single channel MAC protocols. Traditionally, the channelization structure in IEEE 802.11 based wireless networks is pre-configured, and the entire available spectrum is divided into subchannels and equal channel widths. In contrast, this paper presents a Traffic-Aware Channelization MAC (TAC-MAC) protocol for wireless ad hoc networks, where each node is equipped with a single half duplex transceiver. TAC-MAC works in a distributed, fine-grai-ned manner, which dynamically divides variable-width subchannels and allocates subchannel width based on the Orthogonal Frequency Division Multiplexing (OFDM) technique according to the traffic demands of nodes. Simulations show that the TAC-MAC can significantly improve network throughput and reduce packet delay compared with both fixed-width multi-channel MAC and single channel 802.11 protocols, which illustrates a new paradigm for high-efficient multi-channel MAC design in wireless ad hoc networks. 相似文献
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直线段特征是广泛应用于图像分析与处理领域的一种特征,直线段提取是基于特征的模式识别和图像匹配的一个重要步骤,直线段提取方法的优劣直接影响到高层次图像处理的复杂度和处理的效果。针对目前直线段提取方法中存在的直线段端点不准确和直线段断裂问题,提出了一种新的基于HOG特征的直线段提取方法。该方法利用矩阵的行、列积分运算实现对原始图像特定方向直线段的投影,根据矩形函数的一阶导数性质将确定直线段端点位置的问题转化为对列方向向量的求导问题,从而更能有效提取出图像中的直线段。理论分析和实验结果表明:该方法能够快速、准确地提取直线段,在一定程度上解决了经典方法中直线段断裂及端点不准确问题。 相似文献