Weakly Supervised Classification of PolSAR Images Based on Sample Refinement with Complex-Valued Convolutional Neural Network
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摘要:
针对物体框标注样本包含大量异质成分的问题,该文提出了一种基于复值卷积神经网络(CV-CNN)样本精选的极化SAR(PolSAR)图像弱监督分类方法。该方法首先采用CV-CNN对物体框标注样本进行迭代精选,并同时训练出可直接用于分类的CV-CNN。然后利用所训练的CV-CNN完成极化SAR图像的分类。基于3幅实测极化SAR图像的实验结果表明,该文方法能够有效剔除异质样本,与采用原始物体框标注样本的传统全监督分类方法相比可以获得明显更优的分类结果,并且该方法采用CV-CNN比采用经典的支持矢量机(SVM)或Wishart分类器性能更优。
Abstract:In this study, a weakly supervised classification method is proposed to classify the Polarimetric Synthetic Aperture Radar (PolSAR) images based on sample refinement using a Complex-Valued Convolutional Neural Network (CV-CNN) to solve the problem that the bounding-box labeled samples contain many heterogeneous components. First, CV-CNN is used for iteratively refining the bounding-box labeled samples, and the CV-CNN that can be used for direct classification is trained simultaneously. Then, the given PolSAR image is classified using the trained CV-CNN. The experimental results obtained using three actual PolSAR images demonstrate that the heterogeneous components can be effectively eliminated using the proposed method, obtaining significantly better classification results when compared with those obtained using the traditional fully supervised classification method in which original bounding-box labeled samples are used. Furthermore, the proposed method with CV-CNN is superior to those in which the classical Support Vector Machine(SVM) and Wishart classifier are used.
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表 1 实验数据1的分类精度(%)、总体精度(%)和Kappa系数
Table 1. Classification accuracy (%), overall accuracy (%) and Kappa coefficient for experimental data 1
方法 蚕豆 豌豆 树林 苜蓿 小麦1 甜菜 土豆 裸地 草地 CV-CNN全监督 56.43 89.02 99.21 20.37 97.12 80.63 49.86 100.00 30.96 CV-CNN弱监督 56.14 98.35 85.18 92.72 88.23 89.00 70.87 100.00 85.56 Wishart全监督 56.51 81.19 88.15 39.88 54.74 35.49 67.11 0.68 0.11 Wishart弱监督 61.63 80.52 81.46 85.90 73.71 91.21 63.84 99.71 62.02 SVM全监督 85.43 74.37 71.80 67.52 68.37 52.59 78.21 21.05 0 SVM弱监督 81.77 73.20 68.44 58.26 61.42 55.45 75.99 27.18 0 方法 油菜籽 大麦 小麦2 小麦3 水域 建筑区 总体精度 Kappa系数 CV-CNN全监督 48.35 95.74 94.36 91.29 90.41 96.22 76.87 0.7473 CV-CNN弱监督 48.21 93.66 95.69 89.81 81.69 99.37 84.58 0.8323 Wishart全监督 19.48 97.48 76.32 53.16 80.51 91.81 58.02 0.5440 Wishart弱监督 44.47 87.02 67.36 68.58 37.47 90.13 69.38 0.6674 SVM全监督 31.42 29.47 39.90 75.97 77.51 67.75 57.09 0.5352 SVM弱监督 36.51 34.76 39.51 70.24 76.72 70.27 56.58 0.5291 表 2 实验数据2的分类精度(%)、总体精度(%)和Kappa系数
Table 2. Classification accuracy (%), overall accuracy (%) and Kappa coefficient for experimental data 2
方法 农田 植被 水域 建筑区 总体精度 Kappa系数 CV-CNN全监督 82.42 90.41 98.79 64.91 82.14 0.7458 CV-CNN弱监督 93.34 91.38 98.76 75.88 90.02 0.8537 Wishart全监督 99.76 55.95 0.05 13.07 36.36 0.1515 Wishart弱监督 99.76 34.09 0.01 20.22 34.54 0.1272 SVM全监督 84.33 59.42 71.18 52.22 73.52 0.6073 SVM弱监督 88.07 52.05 93.66 38.79 70.40 0.5797 表 3 实验数据3的分类精度(%)、总体精度(%)和Kappa系数
Table 3. Classification accuracy (%), overall accuracy (%) and Kappa coefficient for experimental data 3
方法 水域 植被 城区A 城区B 城区C 总体精度 Kappa系数 CV-CNN全监督 99.37 82.37 7.55 88.89 91.57 74.56 0.6466 CV-CNN弱监督 99.43 91.98 81.84 80.09 82.84 91.05 0.8731 Wishart全监督 95.58 63.34 23.14 33.05 32.03 45.76 0.3219 Wishart弱监督 86.68 61.32 51.52 24.99 31.77 45.92 0.3239 SVM全监督 85.53 26.71 56.13 23.44 38.99 54.34 0.3802 SVM弱监督 88.51 27.71 56.55 27.44 35.86 54.87 0.3940 -
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