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arXiv 2111.09957cs.CVeess.IV

重新思考用于实时语义分割的膨胀卷积

Rethinking Dilated Convolution for Real-time Semantic Segmentation

University of Toronto(多伦多大学)

Roland Gao

AI总结:

本文提出RegSeg模型,通过在整个骨干网络中使用大膨胀率膨胀卷积、可微神经架构搜索优化膨胀率以及轻量级解码器,在实时语义分割任务上以较高FPS取得有竞争力的mIOU,且无需ImageNet预训练。

摘要:

在设计语义分割模型时,视场(field-of-view)是一个重要指标。为了获得较大的视场,以往方法通常选择快速降低分辨率,通常使用平均池化或步长为2的卷积。我们采用不同的方法,在整个骨干网络中使用具有大膨胀率的膨胀卷积,使骨干网络能够通过调整膨胀率轻松调节其视场,并证明该方法与现有方法相比具有竞争力。为了有效使用膨胀卷积,我们给出了膨胀率的一个简单上界,以避免在卷积权重之间留下空隙,并设计了一种受SE-ResNeXt启发的块结构,该结构使用两个并行的$3\ imes 3$卷积,具有不同的膨胀率,以保留局部细节。手动为每个块调整膨胀率可能很困难,因此我们还引入了一种可微神经架构搜索方法,使用梯度下降来优化膨胀率。此外,我们提出了一种轻量级解码器,能够比常见替代方案更好地恢复局部信息。为了证明我们方法的有效性,我们的模型RegSeg在实时Cityscapes和CamVid数据集上取得了有竞争力的结果。使用T4 GPU和混合精度,RegSeg在Cityscapes测试集上以$37$ FPS达到78.3 mIOU,在CamVid测试集上以$112$ FPS达到80.9 mIOU,两者均未使用ImageNet预训练。

英文摘要:

The field-of-view is an important metric when designing a model for semantic segmentation. To obtain a large field-of-view, previous approaches generally choose to rapidly downsample the resolution, usually with average poolings or stride 2 convolutions. We take a different approach by using dilated convolutions with large dilation rates throughout the backbone, allowing the backbone to easily tune its field-of-view by adjusting its dilation rates, and show that it's competitive with existing approaches. To effectively use the dilated convolution, we show a simple upper bound on the dilation rate in order to not leave gaps in between the convolutional weights, and design an SE-ResNeXt inspired block structure that uses two parallel $3\times 3$ convolutions with different dilation rates to preserve the local details. Manually tuning the dilation rates for every block can be difficult, so we also introduce a differentiable neural architecture search method that uses gradient descent to optimize the dilation rates. In addition, we propose a lightweight decoder that restores local information better than common alternatives. To demonstrate the effectiveness of our approach, our model RegSeg achieves competitive results on real-time Cityscapes and CamVid datasets. Using a T4 GPU with mixed precision, RegSeg achieves 78.3 mIOU on Cityscapes test set at $37$ FPS, and 80.9 mIOU on CamVid test set at $112$ FPS, both without ImageNet pretraining.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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