基于光谱—空间注意力双边网络的高光谱图像分类

Spectral-spatial attention bilateral network for hyperspectral image classification

在过去几年里,卷积神经网络已经在高光谱图像分类上取得良好的效果,然而高光谱图像的高维性和卷积神经网络对所有波段的平等处理,限制了这些方法性能。本文提出了一种端到端的光谱空间注意力双边网络SSABN(Spectral-Spatial Attention Bilateral Network),直接将原始图像3D块作为输入数据,而不需要进行预处理。首先,通过光谱空间注意力模块从原始数据中增强有用波段,抑制无效波段。然后,设计双边网络两条路径。其中,空间路径用于提取空间信息,上下文路径用于提供更大的感受野,并通过特征融合模块有效的结合特征。实验结果表明,SSABN在3个公开数据集上取得了更高的分类精度,同时有效的减少训练时间。

HypeSspectral Image Classification(HSIC)is a pixel-level classification problem,and it involves classifying each pixel in the hyperspectral image and confirming the pixel category.However,discriminative features in HSIC task are difficult to acquire and learn,and the extraction of sufficient and effective features directly affects the classification results.In the past few years,Convolutional Neural Networks(CNNs)have achieved better results in HSIC,but the high dimensionality of hyperspectral images and the equal processing of all bands by CNNs have limited the performance of CNN.This study proposes an end-to-end Spectral-Spatial Attention Bilateral Network(SSABN)for HSIC.The network directly uses 3D blocks of the original image as input data without the complicated preprocessing.First,the original data are processed through the spectral-spatial attention module to enhance the useful bands or pixels for classification and suppress invalid information.Then,the spatial and context paths of the bilateral network are designed.The spatial path has three layers,and each layer is composed of convolution,batch normalization,and Relu activation function to extract spatial information.The context path is composed of three downsampling and attention refining modules.The downsampling is used to provide receptive field,and the attention refinement module is used to refine downsampling features.Finally,a feature fusion module is designed to fuse different levels of features through maximum pooling and average pooling for generating discriminative features.Compared with common CNN,SSABN can adaptively enhance effective information,extract more abstract discriminative features,and consume less training time.Experimental results show that SSABN has good fitting ability in different training sample ratios.In the results of ablation experiments,the accuracy of the spectral-spatial attention mechanism is 1%—2%higher than those of other mainstream attention mechanisms,and the feature fusion module can improve the discrimination of extracted features.In the experiments of three public datasets,the classification accuracy of SSABN is higher than 99%,and the training time is less than those of other methods.The classification performance of SSABN is better than those of other hyperspectral image classification algorithms,while reducing its training time can more effectively improve accuracy and efficiency.