基于卷积神经网络和光谱敏感度的高光谱影像分类方法

Classification of hyperspectral images based on a convolutional neural network and spectral sensitivity

目的:由于高光谱成像的特性,高光谱遥感影像较光学、多光谱影像具有更多的光谱信息,因此对高光谱影像地物的分类也相对困难。为提高分类精度,本文提出一个新的高光谱遥感影像分类模型。创新点:考虑到不同的地物覆盖对不同波段范围的电磁波有不同的敏感度,本文提出一个基于卷积神经网络和光谱敏感度的深度学习模型,以提高对高光谱遥感影像地物分类的准确率。通过在最终的分类器后添加一个光谱权重,该模型能够更准确地分类地物。方法:1.将带标记的样本在光谱维度上分为可见光和红外波段,并将部分样本作为训练集和测试集输入到网络中进行训练。2.训练完成后利用模型对全图进行预测,并通过部分预测结果计算出未识别率δ和误识别率γ两个参数。3.利用δ和γ可计算出不同光谱范围的光谱权重并将其置于分类器前(图5)。结论:1.模型加入光谱权重后的分类准确率较之前提高了约2%。2.利用公共数据集测试后显示,使用了光谱权重的卷积神经网络模型的分类精度比未使用光谱权重的模型高约1%。3.本文结果显示,利用不同地物对电磁波的敏感性差别可以增加不同地物间的差异,从而提升分类模型的性能。

In recent years,deep learning methods have gradually come to be used in hyperspectral imaging domains.Because of the peculiarity of hyperspectral imaging,a mass of information is contained in the spectral dimensions of hyperspectral images.Also,different ob jects on a land surface are sensitive to different ranges of wavelength.To achieve higher accuracy in classification,we propose a structure that combines spectral sensitivity with a convolutional neural network by adding spectral weights derived from predicted outcomes before the final classification layer.First,samples are divided into visible light and infrared,with a portion of the samples fed into networks during training.Then,two key parameters,unrecognized rate(δ)and wrongly recognized rate(γ),are calculated from the predicted outcome of the whole scene.Next,the spectral weight,derived from these two parameters,is calculated.Finally,the spectral weight is added and an improved structure is constructed.The improved structure not only combines the features in spatial and spectral dimensions,but also gives spectral sensitivity a primary status.Compared with inputs from the whole spectrum,the improved structure attains a nearly 2%higher prediction accuracy.When applied to public data sets,compared with the whole spectrum,on the average we achieve approximately 1%higher accuracy.