Spatiospectral Feature Extraction and Classification of Hyperspectral Images Using 3D-CNN + ConvLSTM Model

Abstract

Hyperspectral images (HSIs) are contiguous bands captured beyond the visible spectrum. The evolution of deep learning techniques places a massive impact on hyperspectral image classification. Curse of dimensionality is one of the significant issues of hyperspectral image analysis. Therefore, most of the existing classification models perform principal component analysis (PCA) as the dimensionality reduction (DR) technique. Since hyperspectral images are nonlinear, linear DR techniques fail to reserve the nonlinear features. The usage of both spatial and spectral features together improves the classification accuracy of the model. 3D-convolutional neural networks (CNN) extract the spatiospectral features for classification, whereas it is not considering the dependencies in features. This research work proposes a new model for HSI classification using 3D-CNN and convolutional long short-term memory (ConvLSTM). The optimal band extraction is performed by a hybrid DR technique, which is the combination of Gaussian random projection (GRP) and Kernel PCA (KPCA). The proposed deep learning model extracts spatiospectral features using 3D-CNN and dependent spatial features using 2D-ConvLSTM in parallel. Combination of extracted features is fed into a fully connected network for classification. The experiment is performed on three widely used datasets, and the proposed model is compared against the various state-of-the-art techniques and found better classification accuracy.