A Simplified 2D-3D CNN Architecture for Hyperspectral Image Classification Based on Spatial–Spectral Fusion

Convolutional neural networks (CNN) have led to a successful breakthrough for hyperspectral image classification (HSIC). Due to the intrinsic spatial-spectral specificities of a hyperspectral cube, feature extraction with 3-D convolution operation is a straightforward way for HSIC. However, the overwhelming features obtained from the original 3-D CNN network suffers from the overfitting and more training cost problem. To address this issue, in this article, a novel HSIC framework based on a simplified 2D-3D CNN is implemented by the cooperation between a 2-D CNN and a 3-D convolution layer. First, the 2-D convolution block aims to extract the spatial features abundantly involved spectral information as a training channel. Then, the 3-D CNN approach primarily concentrates on exploiting band co-relation data by using a reduced kernel. The proposed architecture achieves the spatial and spectral features simultaneously based on a joint 2D-3D pattern to achieve superior fused feature for the subsequent classification. Furthermore, a deconvolution layer intends to enhance the robustness of the deep features is utilized in the proposed CNN network. The results and analysis of extensive real HSIC experiments demonstrate that the proposed light-weighted 2D-3D CNN network can effectively extract refined features and improve the classification accuracy.