稀疏点云表征下的近场SAR目标识别方法
Near-Field SAR Target Recognition Method Based on Sparse Point-Cloud Representation
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摘要: 毫米波雷达近场成像与目标识别在安防领域具有重要的应用潜力,然而传统基于卷积神经网络(Convolutional Neural Network, CNN)的识别方法具有较高的计算复杂度,制约了其在终端实际部署。为此,本文提出一种融合稀疏表示与点云处理的轻量级目标识别框架。首先,采用基于结构化随机傅里叶变换的正交匹配追踪(Subsampled Random Fourier Transform-Orthogonal Matching Pursuit, SRFT-OMP)算法对雷达图像进行稀疏重构,并提取显著关键点以构建二维稀疏点云,从而在降低输入规模与数据冗余的同时保留目标的关键特征;其次,针对稀疏非均匀二维点云的表征特点,设计了一种高效分类网络 PointSENet++。该网络通过引入多尺度特征提取模块与通道注意力机制,能够有效融合局部几何结构信息与全局显著特征;最后,在基于TI AWR1642BOOST毫米波雷达与三轴滑台构建的近场成像数据集上开展实验验证。结果表明,所提方法仅需1.79M参数即可达到98.84%的分类准确率,整体性能优于多种传统的图像与点云基线模型。实验结果验证了该方法在自建数据集上具有较高的识别精度,并在参数规模与计算开销方面表现出良好的轻量化优势,展现出在实际安防系统中进行嵌入式部署的潜力。Abstract: Millimeter-wave radar near-field imaging and target recognition have significant application potential in the security field. However, traditional recognition methods based on convolutional neural networks usually involve high computational complexity, which limits their practical deployment on terminal devices. To address this issue, this study proposes a lightweight target recognition framework that integrates sparse representation with point-cloud processing. First, the radar images are sparsely reconstructed using the subsampled random Fourier transform-orthogonal matching pursuit algorithm. Salient key points are extracted to construct two-dimensional (2D) sparse point clouds, thereby reducing the input size and data redundancy while preserving the key target features. Second, an efficient classification network named PointSENet++ is designed, considering the representation characteristics of sparse and non-uniform 2D point clouds. The network can effectively fuse local geometric structure information with global salient features by introducing a multi-scale feature extraction module and channel attention mechanism. Finally, experiments are conducted on a near-field imaging dataset constructed using the TI AWR1642BOOST millimeter-wave radar and a three-axis sliding platform. The results demonstrate that the proposed method achieves a classification accuracy of 98.84% with only 1.79M parameters, and its overall performance surpasses that of various conventional image- and point-cloud-based baseline models. The experimental results verify that the proposed method achieves high recognition accuracy on the self-constructed dataset, while also exhibiting favorable lightweight advantages in terms of parameter scale and computational cost, demonstrating its potential for embedded deployment in practical security systems.
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