粗粒度类别信息引导的精细化遥感地物分类

Coarse-Grained Category Information-Guided Fine-Grained Remote Sensing Land Cover Classification

  • 摘要: 地物分类是遥感图像解译的重要任务之一,可以精细地分析地形地貌,在城市规划、灾害监测等领域发挥着十分重要的作用。合成孔径雷达(Synthetic Aperture Radar,SAR)图像由于全天时、全天候、分辨率高、覆盖面积大的特点在地物分类领域应用广泛。然而,SAR图像同时也有很多的限制: SAR图像由于独特的成像机制包含大量的阴影和噪声;高分辨率的SAR遥感图像地物分布复杂,目标尺度差异大,缺乏色彩信息,容易产生边界模糊和类别混淆的问题。对此,本文提出了粗粒度类别信息引导的精细化地物分类方法,利用多尺度语义特征和粗略类别信息引导来增强模型的有效语义特征提取能力和类别判别能力,提高模型的分割性能。针对SAR图像包含大量阴影和噪声的问题,利用残差神经网络(ResNet50)提取多尺度编码特征,通过跳跃连接的解码器和多尺度空洞卷积金字塔池化模块(Atrous Spatial Pyramid Pooling,ASPP)提取图像的多尺度语义特征,增强上下文建模能力,更好地保持边缘和结构信息,增强对噪声干扰的鲁棒性。针对SAR图像地物边界模糊和类别混淆的问题,设计了粗粒度类别信息引导模块,利用类空间特征和语义空间特征生成动态的语义原型,并进一步对语义空间特征进行加权,增强不同地物类别间的判别性。在WHU-OPT-SAR数据集的SAR图像上进行实验,结果表明该算法在保持边缘清晰度的同时提高了对复杂场景中语义结构的判别能力,特别对道路、水域等易混淆语义类别的分割精度显著提升。

     

    Abstract: ‍ ‍Land cover classification is an important task for remote sensing image interpretation that is employed for detailed terrain and landform analysis and plays a critical role in urban planning, disaster monitoring, and other fields. Synthetic aperture radar (SAR) images are widely used in land cover classification owing to their all-day, all-weather capability, high resolution, and large coverage area. However, SAR images also have limitations: they contain numerous shadows and significant noise due to their unique imaging mechanism. High-resolution SAR images are characterized by complex land cover distributions, large scale variations among targets, and lack of color information. This can easily cause boundary blurring and category confusion. In this paper, we propose a refined land cover classification method guided by coarse-grained category information. This method leverages multi-scale semantic features and coarse category information guidance to enhance the effective semantic feature extraction ability, category discrimination ability, and segmentation performance of a model. To address the issue of numerous shadows and significant noise in SAR images, we propose to employ a residual neural network (ResNet50) for multi-scale feature extraction. The extracted features are processed through a skip-connected decoder combined with an atrous spatial pyramid pooling (ASPP) module, which enhances context modeling capabilities, further preserves edge and structural information, and improves robustness against noise interference. To address the problem of unclear boundaries and category confusion in SAR images, we designed a coarse-grained category guidance module. This module generates dynamic semantic prototypes using class and semantic space features and then weights semantic features to enhance inter-category discrimination. Experiments on the WHU-OPT-SAR dataset show that our algorithm exhibits better semantic structure discrimination in complex scenes while preserving edge clarity. It particularly boosts segmentation accuracy for easily confused categories such as roads and waters.

     

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