Global average pooling (GAP) plays an important role in traditional channel attention. However, there is the disadvantage of insufficient information to use the result of GAP as the channel scalar. At the same time, the existing spatial attention models focus on the areas of interest using average pooling or convolutional networks, but there is a loss of feature information and neglect of the structural feature. In this paper, dual wavelet attention is proposed, which can effectively alleviate the aforementioned problems and enhance the representation ability of CNNs. Firstly, the equivalence between the sum of the low-frequency subband coefficients of 2D DWT (Haar) and GAP is proved. On this basis, the statistical characteristics of low-frequency and high-frequency subbands are effectively combined to obtain the channel scalars, which can better measure the importance of each channel. In addition, 2D DWT can effectively capture the approximate and detailed structural features. Thus, wavelet spatial attention is proposed, which can effectively focus on the key spatial structural features. Different from traditional spatial attention, it can better curve the structural and spatial attention for different channels. The experiments are verified on four natural image data sets and three remote sensing scene classification data sets, which shows the effectiveness and versatility of the proposed methods. The code of this paper will be available at https://github.com/yutinyang/DWAN.

Deep convolutional neural networks (CNNs) are significant in remote sensing. Due to the strong local representation learning ability, CNNs have excellent performance in remote sensing scene classification. However, CNNs focus on location-sensitive representations in the spatial domain and lack contextual information mining capabilities. Meanwhile, remote sensing scene classification still faces challenges, such as complex scenes and significant differences in target sizes. To address the problems and challenges above, more robust feature representation learning networks are necessary. In this paper, a novel and explainable spatial-frequency multi-scale Transformer framework, SF-MSFormer, is proposed for remote sensing scene classification. It mainly comprises spatial-domain and frequency-domain multi-scale Transformer branches, which consider the spatial-frequency global multi-scale representation features. Besides, the texture-enhanced encoder is designed in the frequency-domain multi-scale Transformer branch, which is adaptive to capture the global texture features. In addition, an adaptive feature aggregation module is designed to integrate the spatial-frequency multi-scale feature for final recognition. The experimental results verify the effectiveness of SF-MSFormer and show better convergence. It achieves state-of-the-art results (98.72%, 98.6%, 99.72%, and 94.83% overall accuracies, respectively) on the AID, UCM, WHU-RS19, and NWPU-RESISC45 datasets. Besides, the feature visualizations evaluate the explainability of the texture-enhanced encoder. The code implementation of this article will be available at https://github.com/yutinyang/SF-MSFormer.

The foundation model (FM) has garnered significant attention for its remarkable transfer performance in downstream tasks. Typically, it undergoes task-agnosticpre-training on a large dataset and can be efficiently adapted to various downstream applications through fine-tuning. While FMs have been extensively explored in language and other domains, their potential in remote sensing has also begun to attract scholarly interest. However, comprehensive investigations and performance comparisons of these models on remote sensing tasks are currently lacking. In this survey, we provide essential background knowledge by introducing key technologies and recent developments in FMs. Subsequently, we explore essential downstream applications in remote sensing, covering classification, localization, and understanding. Our analysis encompasses over thirty FMs in both natural and remote sensing fields, and we conduct extensive experiments on more than ten datasets, evaluating global feature representation, local feature representation, and target localization. Through quantitative assessments, we highlight the distinctions among various foundation models and confirm that pre-trained large-scale natural FMs can also deliver outstanding performance in remote sensing tasks. After that, we systematically presented a brain-inspired framework for remote sensing foundation models (RSFMs). We delve into the brain-inspired characteristics in this framework, including structure, perception, learning, and cognition. To conclude, we summarize twelve open problems in RSFMs, providing potential research directions. Our survey offers valuable insights into the burgeoning field of RSFMs and aims to foster further advancements in this exciting area

Brain-inspired algorithms have become a new trend in next-generation artificial intelligence. Through research on brain science, the intelligence of remote sensing algorithms can be effectively improved. This paper summarizes and analyzes the essential properties of brain cognise learning and the recent advance of remote sensing interpretation. Firstly, this paper introduces the structural composition and the properties of the brain. Then, five represent brain-inspired algorithms are studied, including multiscale geometry analysis, compressed sensing, attention mechanism, reinforcement learning, and transfer learning. Next, this paper summarizes the data types of remote sensing, the development of typical applications of remote sensing interpretation and the implementations of remote sensing, including datasets, software, and hardware. Finally, the top ten open problems and the future direction of brain-inspired remote sensing interpretation are discussed. This work aims to comprehensively review the brain mechanisms and the development of remote sensing and to motivate future research on brain-inspired remote sensing interpretation.

In recent years, the enormous demand for computing resources resulting from massive data and complex network models has become the limitation of deep learning. In the large-scale problems with massive samples and ultrahigh feature dimensions, sparsity has gradually drawn much attention from academia and the industrial field. In this article, the new generation of brain-inspired sparse learning is reviewed comprehensively. First, sparse cognition learning is introduced from the visual biology mechanism to modeling for the natural image. Second, the sparse representation algorithms are summarized to sort out the research progress of sparse learning. Third, the relevant research on sparse feature selection learning is reviewed. Then, the sparse deep networks and applications are summed up. Last but not least, ten public issues and challenges of sparse learning are discussed. By investigating the development process of sparse learning, this article summarizes the advantages, disadvantages, limitations, and future research directions of the algorithm, which can help readers conduct further study.

In deep learning, convolutional neural networks (CNNs) and Transformer have gained excellent achievements in remote sensing scene parsing. Strong feature representation ability is still a challenge for them. Besides, the complex scenes are still essential challenges for deep learning in remote sensing scene parsing. In this paper, an efficient local-global lifting Transformer framework (LGLFormer) is proposed to ease the challenges above. It effectively combines CNNs, Transformer, and wavelet transform to build a strong local-global feature representation network. Besides, global feature learning driven by local-global adaptive features is proposed based on the 2D local-global adaptive feature extractor and refined global feature attention module. The 2D local-global lifting feature extractor is inspired by the lifting scheme, which introduces local and global dependency. Furthermore, two local-global lifting schemes are proposed, including the series and parallel modes, which can effectively learn local-global relations between pixels. Finally, experiments are validated on three remote sensing benchmark datasets. The proposed LGLFormer achieves the state-of-the-art with 99.02%, 99.2%, and 99.48% overall accuracy on AID, WHU-RS19 and UCM datasets, respectively. In addition, LGLFormer shows good convergence with competitive parameters. The experimental code will be available at https://github.com/yutinyang/LGLFormer.