Convolutional neural networks (CNNs) have been widely employed for hyperspectral image (HSI) classification due to their powerful ability to extract local spatial features. However, CNN-based methods cannot establish long-range dependencies among sequences of pixels. Transformers offer significant advantages when processing sequential data and can establish global relationships, but they still encounter a number of challenges, such as their limited spatial feature extraction ability, or their high computational cost. In order to address the aforementioned issues, we develop a new fast HSI classification approach combining transformers and SimAM-based CNNs. The latter are utilized to extract better spatial features, where the complex spatial characteristics of HSIs are retrieved using an improved hierarchical 2D dense network structure. A dual attention unit (DAU) mechanism is then utilized to direct the model’s attention to discriminative spatial pixel characteristics and effective feature map channels, while suppressing information that is irrelevant for classification purposes. Regarding the spectral features, after extracting hierarchical local characteristics from various convolutional layers (using the hierarchical dense network structure), a squeezed-enhanced axial transformer is employed to establish global long-range dependencies whilst enhancing the ability of the model to extract local detail features in the HSI. Besides, a new Lion optimizer is utilized to improve the classification performance of our model. Our quantitative and comparative experiments on four benchmark datasets demonstrate the effectiveness of the proposed approach provides better classification results than other state-of-the-art approaches. Moreover, our FTSCN also achieves better classification results than other methods in practical scenarios.

Convolutional neural network (CNN) has been successfully introduced to hyperspectral image (HSI) classification and achieved effective performance. With the depth of the CNN increases, it may cause the gradient to become zero, and the structure lacks the utilization of the correlated spatial feature information between different convolutional layers. At the same time, this single-scale convolution kernel is insufficient in expressing the complex spatial structure information of HSI. In addition, the CNN-based methods treat the HSIs spectral band data as a disordered vector in the process of feature extraction, which abandons the exploitation of its internal spectral correlations. To address these issues, we propose a novel spectral–spatial network classification framework based on multiscale dense connected convolutional network (DenseNet) and bidirection recurrent neural network (Bi-RNN) with attention mechanism network (MDRN). For the proposed MDRN, in terms of spatial feature extraction, a multiscale DenseNet is exploited to combine shallow and deep convolution features to extract the multiscale and complex spatial structure features at each layer. In the aspects of spectral feature extraction, Bi-RNN with attention mechanism is used to capture the inner spectral correlations within a continuous spectrum. Three standard real hyperspectral datasets were used to verify the effectiveness of the proposed MDRN approach. Experimental results indicate that the proposed MDRN method can make full use of the spectral and spatial information of the image, and it has better performance than some advanced algorithms in HSI classification. Finally, in the application of hyperspectral data captured by Gaofen-5 satellite, the practicability of the proposed MDRN method is also superior to other methods.

Processing high-dimensional data cubes and developing high-performance classifiers are core objectives in the field of hyperspectral image classification (HSIC). Superpixel-based methods are widely used in HSIC due to their efficacy in reducing redundant information and enhancing local features. However, imprecise segmentation, especially in complex structures and textures of hyperspectral images (HSIs), may lead to inconsistencies in the regions extracted by superpixels and the boundaries between different ground objects. Such inconsistencies significantly degrade the classification performance of HSIs. Alternatively, when parameter settings are inaccurate, edge-aware feature extraction methods often introduce sharpening artifacts at the image boundaries, resulting in a decrease in classification accuracy. To effectively address these challenges, we propose a novel probabilistic fusion method for HSIC. This method consists of the following stages. First, spatial information is extracted by a multiscale superpixel segmentation method and then probabilistically optimized by the extended random walk (ERW) method. Next, semantic-aware structural features (S2Fs) are extracted along with edge information of different objects. Lastly, a probabilistic framework is proposed to fuse the class probabilities of superpixel-based spatial information and semantic-aware structural features. Experimental results on three real datasets show state-of-the-art classification performance, even with limited training sets.

Convolutional Neural Networks (CNNs) and Transformers have made remarkable achievements in hyperspectral image classification (HSIC). Unfortunately, CNN-based methods struggle to capture the contextual dependencies between pixels in HSIs, while Transformer-based methods suffer from quadratic computational complexity. Recently, the Mamba model has shown great potential as it can describe long-range dependencies between HSI pixels with linear computational complexity. Yet, Mamba still faces significant challenges in terms of global modeling. Inspired by the Mamba model framework and Transformers, a novel Dual-Branch Mamba-Like Linear Attention (DBMLLA) network is proposed for HSIC, achieving efficient global dependency modeling. Specifically, the proposed DBMLLA combines an embedding module, a Spatial-Spectral Mamba-Like Linear Attention (SS-MLLA) module, and a fusion module. In the embedding module, an absolute position embedding module is introduced for better extraction of global features. In the SS-MLLA module, we design the Spatial Mamba-Like Linear Attention (SpaMLLA) block and the Spectral Mamba-Like Linear Attention (SpeMLLA) block to exploit the spatial and spectral information of the HSI. In addition, SS-MLLA is improved by utilising Depthwise Separable Convolution (DSC) to enhance the model’s ability to extract deeper local feature information. Through experiments conducted on four public hyperspectral datasets, it is demonstrated that the proposed model consistently outperforms state-of-the-art approaches.

Extracting discriminative spectral-spatial features from hyperspectral images (HSIs) remains a crucial topic within the remote sensing community. However, most feature extraction methods suffer from coarse textures, leading to poor performance in classifying HSIs. Moreover, limited training samples can significantly hinder the generalization ability of classifiers, hindering performance improvements in hyperspectral image classification (HSIC). To address these issues, a proposed dual-branch structural feature extraction method fully leverages the global and local information, preserving key structures while removing unimportant textures. The key steps of our method are detailed below: First, an image fusion technique is performed on HSIs to obtain dimension-reduced HSIs. Second, a global multiscale feature extraction method is proposed by performing different parameter settings of pyramid texture filtering (PTF) on HSIs and global probability can be obtained. Third, a pyramid texture filtering-based local multiscale feature extraction method is proposed using multiscale superpixel segmentation on the finest layer of PTFs and local probability can be obtained. Fourth, a decision fusion rule is applied to integrate class probabilities from the two branches. Experiments performed on three different data sets demonstrate that the proposed method can outperform other state-of-the-art classification methods.