Domain Adaptive Object Detection Based on Attention Mechanism and Cycle Domain Triplet Loss
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摘要: 目前大多数深度学习算法都依赖于大量的标注数据并欠缺一定的泛化能力. 无监督域自适应算法能提取到已标注数据和未标注数据间隐式共同特征, 从而提高算法在未标注数据上的泛化性能. 目前域自适应目标检测算法主要为两阶段目标检测器设计. 针对单阶段检测器中无法直接进行实例级特征对齐导致一定数量域不变特征的缺失, 提出结合通道注意力机制的图像级域分类器加强域不变特征提取. 此外, 对于域自适应目标检测中存在类别特征的错误对齐引起的精度下降问题, 通过原型学习构建类别中心, 设计了一种基于原型的循环域三元损失(Cycle domain triplet loss, CDTL)函数, 从而实现原型引导的精细类别特征对齐. 以单阶段目标检测算法作为检测器, 并在多种域自适应目标检测公共数据集上进行实验. 实验结果证明该方法能有效提升原检测器在目标域的泛化能力, 达到比其他方法更高的检测精度, 并且对于单阶段目标检测网络具有一定的通用性.Abstract: Most current deep learning algorithms rely heavily on large amounts of annotated data and exist deficiency in generalization ability. The unsupervised domain adaptation algorithm can extract the common implicit invariant features from the labeled data and unlabeled data, so that the algorithm can achieve good generalization performance on the unlabeled data. At present, domain adaptation object detection algorithms are mainly designed as two-stage object detectors. For the one-stage object detectors, the difficulty of explicit aligning instance-level features leads to the absence of a number of domain invariant features. In this paper, an image-level domain classifier combined with channel attention mechanism is proposed to strengthen domain invariant feature extraction. In addition, to address the issue of reduced accuracy caused by inaccurate alignment of category features in domain adaptive object detection, a prototype based cycle domain triplet loss (CDTL) function was designed to construct category centers through prototype learning, thereby we can achieve precise category feature alignment guided by prototypes. One-stage object detection algorithms are used as detectors, and experiments are conducted on various domain adaptive object detection public datasets. The experimental results show that our method can effectively improve the generalization ability of the original detector on the target domain and achieves higher detection accuracy than other methods. Meanwhile, the experiment on different detector indicate our method is universal for the one-stage object detection network.
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表 1 不同方法在CityScapes→FoggyCityScapes数据集上的对比实验结果(%)
Table 1 The results of different methods on the CityScapes→FoggyCityScapes dataset (%)
方法 检测器 person rider car truck bus motor bike train mAP mGP DAF[10] Faster R-CNN 25.0 31.0 40.5 22.1 35.3 20.0 27.1 20.2 27.7 38.8 SWDA[11] Faster R-CNN 29.9 42.3 43.5 24.5 36.2 30.0 35.3 32.6 34.3 70.0 C2F[14] Faster R-CNN 34.0 46.9 52.1 30.8 43.2 34.7 37.4 29.9 38.6 79.1 CAFA[16] Faster R-CNN 41.9 38.7 56.7 22.6 41.5 24.6 35.5 26.8 36.0 81.9 ICCR-VDD[21] Faster R-CNN 33.4 44.0 51.7 33.9 52.0 34.2 36.8 34.7 40.0 — MeGA[20] Faster R-CNN 37.7 49.0 52.4 25.4 49.2 34.5 39.0 46.9 41.8 91.1 DAYOLO[28] YOLOv3 29.5 27.7 46.1 9.1 28.2 12.7 24.8 4.5 36.1 61.0 本文方法(v3) YOLOv3 34.0 37.2 55.8 31.4 44.4 22.3 30.8 50.7 38.3 83.9 MS-DAYOLO[31] YOLOv4 39.6 46.5 56.5 28.9 51.0 27.5 36.0 45.9 41.5 68.6 A-DAYOLO[32] YOLOv5 32.8 35.7 51.3 18.8 34.5 11.8 25.6 16.2 28.3 — S-DAYOLO[34] YOLOv5 42.6 42.1 61.9 23.5 40.5 24.4 37.3 39.5 39.0 69.9 本文方法(v5) YOLOv5s 30.9 37.4 53.3 23.8 39.5 24.2 29.9 35.0 34.3 83.8 注: “—”表示该方法没有进行此实验; (v3)表示检测器为YOLOv3; (v5)表示检测器为YOLOv5s; 加粗数值表示对比实验中的最佳结果. 表 2 不同方法在SunnyDay→DuskRainy数据集上的对比实验结果(%)
Table 2 The results of different methods on the SunnyDay→DuskRainy dataset (%)
方法 检测器 bus bike car motor person rider truck mAP $\Delta{\rm{mAP}}$ DAF[10] Faster R-CNN 43.6 27.5 52.3 16.1 28.5 21.7 44.8 33.5 5.2 SWDA[11] Faster R-CNN 40.0 22.8 51.4 15.4 26.3 20.3 44.2 31.5 3.2 ICCR-VDD[21] Faster R-CNN 47.9 33.2 55.1 26.1 30.5 23.8 48.1 37.8 9.5 本文方法(v3) YOLOv3 50.1 24.9 70.7 24.2 39.1 19.0 53.2 40.2 7.4 本文方法(v5) YOLOv5s 46.2 22.1 68.2 16.5 34.8 17.5 50.5 36.5 9.4 注: $\Delta {\rm{mAP}}$表示mAP的涨幅程度. 表 3 不同方法在SunnyDay→NightRainy数据集上的对比实验结果(%)
Table 3 The results of different methods on the SunnyDay→NightRainy dataset (%)
方法 检测器 bus bike car motor person rider truck mAP $\Delta {\rm{mAP}}$ DAF[10] Faster R-CNN 23.8 12.0 37.7 0.2 14.9 4.0 29.0 17.4 1.1 SWDA[11] Faster R-CNN 24.7 10.0 33.7 0.6 13.5 10.4 29.1 17.4 1.1 ICCR-VDD[21] Faster R-CNN 34.8 15.6 38.6 10.5 18.7 17.3 30.6 23.7 7.4 本文方法(v3) YOLOv3 45.0 8.2 51.1 4.0 20.9 9.6 37.9 25.3 5.1 本文方法(v5) YOLOv5s 40.7 9.3 45.0 0.6 12.8 9.2 32.5 21.5 4.7 表 4 KITTI→CityScapes和Sim10k→CityScapes数据集上的对比实验结果(%)
Table 4 The results of different methods on KITTI→CityScapes and Sim10k→CityScapes datasets (%)
表 5 CityScapes→FoggyCityScapes数据集上基于YOLOv3的消融实验结果(%)
Table 5 The results of ablation experiment on CityScapes→FoggyCityScapes dataset based on YOLOv3 (%)
方法 person rider car truck bus motor bike train mAP SO 29.8 35.0 44.7 20.4 32.4 14.8 28.3 21.6 28.4 CADC 34.4 38.0 54.7 24.4 45.0 21.2 32.1 49.1 37.2 CDTL 31.1 38.0 46.7 28.9 34.5 23.4 27.8 13.7 30.5 CADC + CDTL 34.0 37.2 55.8 31.4 44.4 22.3 30.8 50.7 38.3 Oracle 34.9 38.8 55.9 25.3 45.0 22.6 33.4 49.1 40.2 表 6 CityScapes→FoggyCityScapes数据集上基于YOLOv5s的消融实验结果(%)
Table 6 The results of ablation experiment on CityScapes→FoggyCityScapes dataset based on YOLOv5s (%)
方法 person rider car truck bus motor bike train mAP SO 26.9 33.1 39.9 8.9 21.1 11.3 24.8 4.9 21.4 CADC 32.6 37.1 52.7 26.8 38.1 23.0 38.1 32.6 34.1 CDTL 29.7 36.7 43.2 13.1 25.5 17.1 28.7 13.1 26.2 CADC + CDTL 30.9 37.4 53.3 23.8 39.5 24.2 29.9 35.0 34.3 Oracle 34.8 37.9 57.5 24.4 42.7 23.1 33.2 40.8 36.8 表 7 SunnyDay→DuskRainy数据集上基于YOLOv3的消融实验结果(%)
Table 7 The results of ablation experiment on SunnyDay→DuskRainy dataset based on YOLOv3 (%)
方法 bus bike car motor person rider truck mAP SO 43.7 14.3 68.4 12.0 31.5 10.9 48.7 32.8 CADC 50.0 22.6 70.8 23.2 38.4 18.7 53.5 39.6 CDTL 45.4 20.1 69.2 15.2 34.8 17.2 47.8 35.7 CADC + CDTL 50.1 24.9 70.7 24.2 39.1 19.0 53.2 40.2 表 8 SunnyDay→DuskRainy数据集上基于YOLOv5s的消融实验结果(%)
Table 8 The results of ablation experiment on SunnyDay→DuskRainy dataset based on YOLOv5s (%)
方法 bus bike car motor person rider truck mAP SO 37.2 8.4 63.8 5.5 23.7 7.9 43.4 27.1 CADC 45.6 22.1 68.2 16.6 34.5 15.4 50.1 35.9 CDTL 41.6 13.1 65.5 7.6 29.7 10.2 44.9 30.4 CADC + CDTL 46.2 22.1 68.2 16.5 34.8 17.5 50.5 36.5 表 9 SunnyDay→NightRainy数据集上基于YOLOv3的消融实验结果(%)
Table 9 The results of ablation experiment on SunnyDay→NightRainy dataset based on YOLOv3 (%)
方法 bus bike car motor person rider truck mAP SO 39.2 5.1 44.2 0.2 14.8 6.9 30.7 20.2 CADC 44.4 8.1 50.9 0.6 20.2 11.3 38.3 24.8 CDTL 40.4 8.2 45.8 0.6 16.2 7.2 33.4 21.7 CADC + CDTL 45.0 8.2 51.1 4.0 20.9 9.6 37.9 25.3 表 10 SunnyDay→NightRainy数据集上基于YOLOv5s的消融实验结果(%)
Table 10 The results of ablation experiment on SunnyDay→NightRainy dataset based on YOLOv5s (%)
方法 bus bike car motor person rider truck mAP SO 25.4 3.2 36.3 0.2 9.1 4.4 20.8 14.2 CADC 38.7 8.3 42.7 0.3 12.3 6.4 32.0 20.1 CDTL 34.3 6.2 44.2 0.5 11.2 8.7 30.3 19.3 CADC + CDTL 40.7 9.3 45.0 0.6 12.8 9.2 32.5 21.5 表 11 KITTI→CityScapes和Sim10k→CityScapes数据集上的对比实验结果(%)
Table 11 The results of different methods on KITTI→CityScapes and Sim10k→CityScapes datasets (%)
方法 KITTI Sim10k YOLOv3 SO 59.6 58.5 CADC 60.5 59.6 CDTL 60.5 60.8 CADC + CDTL 61.1 59.8 Oracle 64.7 64.7 YOLOv5s SO 54.0 53.1 CADC 59.5 58.6 CDTL 59.0 60.3 CADC + CDTL 60.0 59.0 Oracle 65.9 65.9 表 12 本文方法在VOC→Clipart1k上的实验(%)
Table 12 The experiment of our method on VOC→Clipart1k (%)
方法 aero bcycle bird boat bottle bus car cat chair cow table dog hrs bike prsn plnt sheep sofa train tv mAP I3Net 23.7 66.2 25.3 19.3 23.7 55.2 35.7 13.6 37.8 35.5 25.4 13.9 24.1 60.3 56.3 39.8 13.6 34.5 56.0 41.8 35.1 I3Net + CDTL 23.3 61.6 27.8 17.1 24.7 54.3 39.8 12.3 41.4 34.1 32.2 15.5 27.6 77.9 57.0 37.4 5.50 31.3 51.8 47.8 36.0 I3Net + CDTL + ${\rm{CADC}}^*$ 31.2 60.4 31.8 19.4 27.0 63.3 40.7 13.7 41.1 38.4 27.2 18.0 25.5 67.8 54.9 37.2 15.5 36.4 54.8 47.8 37.6 表 13 本文方法在VOC→Comic2k上的实验(%)
Table 13 The experiment of our method on VOC→Comic2k (%)
方法 bike bird car cat dog person mAP I3Net 44.9 17.8 31.9 10.7 23.5 46.3 29.2 I3Net + CDTL 43.7 15.1 31.5 11.7 18.6 46.9 27.9 I3Net + CDTL + CADC* 47.8 16.0 33.8 15.1 24.4 43.5 30.1 表 14 本文方法在VOC→Watercolor2k上的实验(%)
Table 14 The experiment of our method on VOC→Watercolor2k (%)
方法 bike bird car cat dog person mAP I3Net 81.3 49.6 43.6 38.2 31.3 61.7 51.0 I3Net + CDTL 79.5 47.2 41.7 33.5 35.4 60.3 49.6 I3Net + CDTL + CADC* 84.1 45.3 46.6 32.9 31.4 61.4 50.3 表 15 像素级对齐对网络的影响(%)
Table 15 The impact of pixel alignment to network (%)
方法 检测器 C→F K→C S→C CDTL + CADC YOLOv3 35.9 59.8 58.4 CDTL + CADC + $D_{{\rm{pixel}}}$ YOLOv3 37.2 60.5 59.6 CDTL + CADC YOLOv5s 32.7 58.9 56.8 CDTL + CADC + $D_{{\rm{pixel}}}$ YOLOv5s 34.1 59.5 58.6 表 16 通道注意力域分类器中损失函数的选择
Table 16 The choice of loss function in channel attention domain classifier
检测器 $F_1$ $F_2$ $F_3$ mAP (%) YOLOv3/v5s CE CE CE 35.8/32.7 YOLOv3/v5s CE CE FL 36.4/33.2 YOLOv3/v5s CE FL FL 37.2/34.1 YOLOv3/v5s FL FL FL 37.0/33.5 -
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