ELM与SVM在高光谱遥感图像监督分类中的比较研究

Comparative Study of ELM and SVM in Hyperspectral Image Supervision Classification

在高光谱遥感图像监督分类过程中加入空间特征信息,可有效提高分类的速度与精度。将空间信息提取方法分水岭法与极限学习机(ELM)和支持向量机(SVM)相结合,对两种分类方法加入空间特征信息前后的分类结果进行时间与精度的综合评价与比较分析。以意大利帕维亚大学(PaviaU)ROSIS和博茨瓦纳(Botswana)奥卡瓦纳三角洲Hyperion高光谱遥感数据进行试验,首先对原始图像数据进行预处理,对不同地物类别选取适当的训练样本作为分类的参考区域,然后对各类别的光谱特征进行分析,并分别运用两种分类方法对数据集进行分类实验;之后将光谱特征与空间特征结合对数据进行分类试验。实验结果表明:在分类时间及精度方面,极限学习机(ELM)均优于支持向量机(SVM);在分类过程中引入空间特征信息,可有效提高分类精度。

Combining the spatial features and spectral feature of hyperspectral remote sensing image in supervised classification can effectively improve the classification time and accuracy.In this study,the spatial information extraction method,named watershed transform,was combined with the Extreme Learning Machine(ELM)and Support Vector Machine(SVM)methods.The classification results of the datasets with the spatial features and without the spatial features were synthetically evaluated and compared.Two hyperspectral datasets,the ROSIS data of Pavia university and the Hyperion data of Okavango Delta(Botswana),were selected to test the methods.After preprocessing,the training samples were selected from the images as the reference areas for each type,and the spectral features of each type were analyzed.The two classification methods were utilized to classify the hyperspectral datasets and relevant classification results were obtained.based on the validation samples selected from the images,the classification results were evaluated using the confusion matrix and the execution times.After that,the spectral features and spatial features were combined to classify the data.The results show that the Extreme Learning Machine(ELM) is superior to the Support Vector Machine(SVM)in the classification time and precision,and the spatial features are introduced in the classification process,which can effectively improve the classification accuracy.