A Two-Branch Convolutional Neural Network Based on Multi-Spectral Entropy Rate Superpixel Segmentation for Hyperspectral Image Classification
Caihong Mu, Zhidong Dong, Yi Liu
Abstract
Convolutional neural networks (CNNs) can extract advanced features of joint spectral–spatial information, which are useful for hyperspectral image (HSI) classification. However, the patch-based neighborhoods of samples with fixed sizes are usually used as the input of the CNNs, which cannot dig out the homogeneousness between the pixels within and outside of the patch. In addition, the spatial features are quite different in different spectral bands, which are not fully utilized by the existing methods. In this paper, a two-branch convolutional neural network based on multi-spectral entropy rate superpixel segmentation (TBN-MERS) is designed for HSI classification. Firstly, entropy rate superpixel (ERS) segmentation is performed on the image of each spectral band in an HSI, respectively. The segmented images obtained are stacked band by band, called multi-spectral entropy rate superpixel segmentation image (MERSI), and then preprocessed to serve as the input of one branch in TBN-MERS. The preprocessed HSI is used as the input of the other branch in TBN-MERS. TBN-MERS extracts features from both the HSI and the MERSI and then utilizes the fused spectral–spatial features for the classification of HSIs. TBN-MERS makes full use of the joint spectral–spatial information of HSIs at the scale of superpixels and the scale of neighborhood. Therefore, it achieves excellent performance in the classification of HSIs. Experimental results on four datasets demonstrate that the proposed TBN-MERS can effectively extract features from HSIs and significantly outperforms some state-of-the-art methods with a few training samples.