Obtaining accurate weather forecasts at station locations is a critical challenge due to systematic biases arising from the mismatch between multi-scale, continuous atmospheric characteristic and their discrete, gridded representations. Previous works have primarily focused on modeling gridded meteorological data, inherently neglecting the off-grid, continuous nature of atmospheric states and leaving such biases unresolved. To address this, we propose theKolmogorov–Arnold Neural Interpolator(KANI), a novel framework that redefines meteorological field representation as continuous neural functions derived from discretized grids. Grounded in the Kolmogorov–Arnold theorem, KANI captures the inherent continuity of atmospheric states and leverages sparse in-situ observations to correct these biases systematically. Furthermore, KANI introduces an innovativezero-shotdownscaling capability, guided by high-resolution topographic textures without requiring high-resolution meteorological fields for supervision. Experimental results across three sub-regions of the continental United States indicate that KANI achieves an accuracy improvement of 40.28% for temperature and 67.41% for wind speed, highlighting its significant improvement over traditional interpolation methods. This enables continuous neural representation of meteorological variables through neural networks, transcending the limitations of conventional grid-based representations.

Change detection, a prominent research area in remote sensing, is pivotal in observing and analyzing surface transformations. Despite significant advancements achieved through deep learning-based methods, executing high-precision change detection in spatiotemporally complex remote sensing scenarios still presents a substantial challenge. The recent emergence of foundation models, with their powerful universality and generalization capabilities, offers potential solutions. However, bridging the gap of data and tasks remains a significant obstacle. In this paper, we introduce Time Travelling Pixels (TTP), a novel approach that integrates the latent knowledge of the SAM foundation model into change detection. TTP can effectively address the domain shift in general knowledge transfer and the challenge of expressing homogeneous and heterogeneous characteristics of multi-temporal images. The state-of-the-art results obtained on the LEVIR-CD underscore the efficacy of the TTP. The code has been made publicly available at https://github.com/KyanChen/TTP.

Detecting clouds and snow in remote sensing images is an essential preprocessing task for remote sensing imagery. Previous works draw inspiration from semantic segmentation models in computer vision, with most research focusing on improving model architectures to enhance detection performance. However, unlike natural images, the complexity of scenes and the diversity of cloud types in remote sensing images result in many inaccurate labels in cloud and snow detection datasets, introducing unnecessary noises into the training and testing processes. By constructing a new dataset and proposing a novel training strategy with the curriculum learning paradigm, we guide the model in reducing overfitting to noisy labels. Additionally, we design a more appropriate model performance evaluation method, that alleviates the performance assessment bias caused by noisy labels. By conducting experiments on models with UNet and Segformer, we have validated the effectiveness of our proposed method. This paper is the first to consider the impact of label noise on the detection of clouds and snow in remote sensing images.

Remote sensing image classification forms the foundation of various understanding tasks, serving a crucial function in remote sensing image interpretation. The recent advancements of Convolutional Neural Networks (CNNs) and Transformers have markedly enhanced classification accuracy. Nonetheless, remote sensing scene classification remains a significant challenge, especially given the complexity and diversity of remote sensing scenarios and the variability of spatiotemporal resolutions. The capacity for whole-image understanding can provide more precise semantic cues for scene discrimination. In this paper, we introduce RSMamba, a novel architecture for remote sensing image classification. RSMamba is based on the State Space Model (SSM) and incorporates an efficient, hardware-aware design known as the Mamba. It integrates the advantages of both a global receptive field and linear modeling complexity. To overcome the limitation of the vanilla Mamba, which can only model causal sequences and is not adaptable to two-dimensional image data, we propose a dynamic multi-path activation mechanism to augment Mamba’s capacity to model non-causal data. Notably, RSMamba maintains the inherent modeling mechanism of the vanilla Mamba, yet exhibits superior performance across multiple remote sensing image classification datasets,e.g., F1 scores of 95.25, 92.63, and 95.18 on the UC Merced, AID, and RESISC45 classification datasets respectively, exceeding those of concurrent Vim and VMamba. This indicates that RSMamba holds significant potential to function as the backbone of future visual foundation models. The code is available at https://github.com/KyanChen/RSMamba.

Leveraging the extensive training data from SA-1B, the Segment Anything Model (SAM) demonstrates remarkable generalization and zero-shot capabilities. However, as a category-agnostic instance segmentation method, SAM heavily relies on prior manual guidance, including points, boxes, and coarse-grained masks. Furthermore, its performance in remote sensing image segmentation tasks remains largely unexplored and unproven. In this paper, we aim to develop an automated instance segmentation approach for remote sensing images, based on the foundational SAM model and incorporating semantic category information. Drawing inspiration from prompt learning, we propose a method to learn the generation of appropriate prompts for SAM. This enables SAM to produce semantically discernible segmentation results for remote sensing images, a concept we have termed RSPrompter. We also propose several ongoing derivatives for instance segmentation tasks, drawing on recent advancements within the SAM community, and compare their performance with RSPrompter. Extensive experimental results, derived from the WHU building, NWPU VHR-10, and SSDD datasets, validate the effectiveness of our proposed method. The code for our method is publicly available at https://kychen.me/RSPrompter.

Accurately retrieving surface meteorological states at arbitrary locations is of great application significance in weather forecasting and climate modeling. Since meteorological variables are typically provided as coarse-resolution gridded fields, common methods that obtain the states at a specific location directly through spatial interpolation can lead to significant accuracy deviations compared to actual observations. Traditional downscaling, the process of obtaining fixed-scale high-resolution meteorological fields from low-resolution inputs, has been proposed as a way to indirectly improve the accuracy of retrieving states at arbitrary locations by providing more detailed subgrid-scale information. However, for arbitrary locations at the station scale, their states are influenced by subgrid information, resulting in systematic biases between the downscaled results after interpolation and the actual observations at specific station locations. To address this issue, in this article, we propose a new task called station-scale downscaling, which aims to directly derive accurate meteorological states at any given station location from a coarse-resolution meteorological field. To achieve this, we propose a new downscaling model based on hypernetwork architecture, namely, HyperDS, which efficiently integrates the multiscale observational information to guide the continuous neural field modeling of the meteorological variables, enabling accurate sampling of the states at any target location. Through extensive experiments, our proposed method outperforms other specially designed baseline models on multiple surface variables. Notably, the mean squared error (mse) for wind speed and surface pressure improved by 67% and 19.5% compared with other methods, respectively.

In an era of frequent extreme weather and global warming, obtaining precise, fine-grained near-surface weather forecasts is increasingly essential for human activities. Downscaling (DS), a crucial task in meteorological forecasting and remote sensing, enables the reconstruction of high-resolution meteorological states for target regions from global-scale forecast results. Previous downscaling methods, inspired by convolutional neural network (CNN) and Transformer-based super-resolution (SR) models, lacked tailored designs for meteorology and encountered structural limitations. Notably, they failed to efficiently integrate topography, a crucial prior to the downscaling process. In this article, we address these limitations by pioneering the selective state-space model (SSM) into the meteorological field downscaling and propose a novel model called MambaDS. This model retains the advantages of Mamba in long-range dependency modeling and linear computational complexity while enhancing the learning ability of multivariate correlation. In addition, by designing an efficient topography constraint layer, this prior information can be used more efficiently than ever before. Through extensive experiments in both China mainland and the continental United States (CONUS), we validated that our proposed MambaDS achieves state-of-the-art (SOTA) results in three different types of meteorological field downscaling settings.

Remote sensing scene classification is an important yet challenging task. In recent years, the excellent feature representation ability of convolutional neural networks (CNNs) has led to substantial improvements in scene classification accuracy. However, handling resolution variations of remote sensing images is still challenging because CNNs are not inherently capable of modeling multiresolution input images. In this letter, we propose a novel scene classification method with scale and resolution adaptation ability by leveraging the recent advances in implicit neural representations (INRs). Unlike previous CNN-based methods that make predictions based on rasterized image inputs, the proposed method converts the images as continuous functions with INRs optimization and then performs classification within the function space. When the image is represented as a function, the image resolution can be decoupled from the pixel values so that the resolution does not have much impact on the classification performance. Our method also shows great potential for multiresolution remote sensing scene classification. Using only a simple multilayer perceptron (MLP) classifier in the proposed function space, our method achieves classification accuracy comparable to deep CNNs but exhibits better adaptability to image scale and resolution changes.

Despite its fruitful applications in remote sensing, image super-resolution is troublesome to train and deploy as it handles different resolution magnifications with separate models. Accordingly, we propose a highly-applicable super-resolution framework called FunSR, which settles different magnifications with a unified model by exploiting context interaction within implicit function space. FunSR composes a functional representor, a functional interactor, and a functional parser. Specifically, the representor transforms the low-resolution image from Euclidean space to multi-scale pixel-wise function maps; the interactor enables pixel-wise function expression with global dependencies; and the parser, which is parameterized by the interactor’s output, converts the discrete coordinates with additional attributes to RGB values. Extensive experimental results demonstrate that FunSR reports state-of-the-art performance on both fixed-magnification and continuous-magnification settings, meanwhile, it provides many friendly applications thanks to its unified nature. Our code is available at https://github.com/KyanChen/FunSR.

Fine-grained image classification can be considered as a discriminative learning process where images of different subclasses are separated from each other while the same subclass images are clustered. Most existing methods perform synchronous discriminative learning in their approaches. Although achieving promising results in fine-grained visual classification (FGVC) in natural images, these methods may fail in fine-grained ship classification (FGSC) problem in remote sensing (RS) images due to the highly “imbalanced fineness" and “imbalanced appearances" of ships among subclasses. To tackle the issue, we propose an asynchronous contrastive learning-based method for effective FGSC. The proposed method, which we refer to as “Push-and-Pull Network (P2Net)", includes a “push-out stage” and a “pull-in stage”, where the first stage forces all the instances to be de-correlated and then the second one groups them into each subclass. A dual-branch network is designed to separate/de-correlate the images with each other, while an Integration Module is designed to aggregate the de-correlated images into their corresponding subclass together with a Proxy-based Module designed for acceleration. In this way, the correlation between subclasses can be decoupled, which in turn makes the final classification much easier. Our method can be trained end-to-end and requires no additional annotations other than category information. Extensive experiments are conducted on two large-scale FGSC datasets (FGSC-23 and FGSCR-42). Our method outperforms other state-of-the-art approaches. Ablation experiments also suggest the effectiveness of our design. Our code is available at https://github.com/WindVChen/Push-and-Pull-Network.

Supervised deep learning models depend on massive labeled data. Unfortunately, it is time-consuming and labor-intensive to collect and annotate bitemporal samples containing desired changes. Transfer learning from pretrained models is effective to alleviate label insufficiency in remote sensing (RS) change detection (CD). We explore the use of semantic information during pretraining. Different from traditional supervised pretraining that learns the mapping from image to label, we incorporate semantic supervision into the self-supervised learning (SSL) framework. Typically, multiple objects of interest (e.g., buildings) are distributed in various locations in an uncurated RS image. Instead of manipulating image-level representations via global pooling, we introduce point-level supervision on per-pixel embeddings to learn spatially sensitive features, thus benefiting downstream dense CD. To achieve this, we obtain multiple points via class-balanced sampling on the overlapped area between views using the semantic mask. We learn an embedding space where background and foreground points are pushed apart, and spatially aligned points across views are pulled together. Our intuition is the resulting semantically discriminative representations invariant to irrelevant changes (illumination and unconcerned land covers) may help change recognition. We collect large-scale image-mask pairs freely available in the RS community for pretraining. Extensive experiments on three CD datasets verify the effectiveness of our method. Ours significantly outperforms ImageNet pretraining, in-domain supervision, and several SSL methods. Empirical results indicate our pretraining improves the generalization and data efficiency of the CD model. Notably, we achieve competitive results using 20% training data than baseline (random initialization) using 100% data. Our code is available athttps://github.com/justchenhao/SaDL_CD.

Training deep learning-based change detection (CD) models heavily relies on large labeled data sets. However, it is time-consuming and labor-intensive to collect large-scale bitemporal images that contain building change, due to both its rarity and sparsity. Contemporary methods to tackle the data insufficiency mainly focus on transformation-based global image augmentation and cost-sensitive algorithms. In this article, we propose a novel data-level solution, namely, Instance-level change Augmentation (IAug), to generate bitemporal images that contain changes involving plenty and diverse buildings by leveraging generative adversarial training. The key of IAug is to blend synthesized building instances onto appropriate positions of one of the bitemporal images. To achieve this, a building generator is employed to produce realistic building images that are consistent with the given layouts. Diverse styles are later transferred onto the generated images. We further propose context-aware blending for a realistic composite of the building and the background. We augment the existing CD data sets and also design a simple yet effective CD model—CD network (CDNet). Our method (CDNet + IAug) has achieved state-of-the-art results in two building CD data sets (LEVIR-CD and WHU-CD). Interestingly, we achieve comparable results with only 20% of the training data as the current state-of-the-art methods using 100% data. Extensive experiments have validated the effectiveness of the proposed IAug. Our augmented data set has a lower risk of class imbalance than the original one. Conventional learning on the synthesized data set outperforms several popular cost-sensitive algorithms on the original data set. Our code and data are available athttps://github.com/justchenhao/IAug_CDNet.

The proliferation of remote sensing satellites has resulted in a massive amount of remote sensing images. However, due to human and material resource constraints, the vast majority of remote sensing images remain unlabeled. As a result, it cannot be applied to currently available deep learning methods. To fully utilize the remaining unlabeled images, we propose a Geographical Knowledge-driven Representation learning method for remote sensing images (GeoKR), improving network performance and reduce the demand for annotated data. The global land cover products and geographical location associated with each remote sensing image are regarded as geographical knowledge to provide supervision for representation learning and network pre-training. An efficient pre-training framework is proposed to eliminate the supervision noises caused by imaging times and resolutions difference between remote sensing images and geographical knowledge. A large scale pre-training dataset Levir-KR is proposed to support network pre-training. It contains 1,431,950 remote sensing images from Gaofen series satellites with various resolutions. Experimental results demonstrate that our proposed method outperforms ImageNet pre-training and self-supervised representation learning methods and significantly reduces the burden of data annotation on downstream tasks such as scene classification, semantic segmentation, object detection, and cloud / snow detection. It demonstrates that our proposed method can be used as a novel paradigm for pre-training neural networks. Codes will be available on https://github.com/flyakon/Geographical-Knowledge-driven-Representaion-Learning.

Global land cover (GLC) products can be utilized to provide geographical supervision for remote sensing representation learning, which has significantly improved downstream tasks’ performance and decreased the demand of manual annotations. However, the time differences between remote sensing images and GLC products may introduce deviations in geographical supervision. In this paper, we propose a Geographical supervision Correction method (GeCo) for remote sensing representation learning. Deviated geographical supervision generated by GLC products can be corrected adaptively using the correction matrix during network pre-training and joint optimization process is designed to simultaneously update the correction matrix and network parameters. Additionally, we identify prior knowledge on geographical supervision to guide representation learning and restrict the correction process. The prior knowledge named “minor changes” implies that the geographical supervision may not change significantly, whereas the prior knowledge named “spatial aggregation” implies that land covers are aggregated in their spatial distribution. According to the prior knowledge, corresponding regularization terms are proposed to prevent abrupt changes in geographical supervision correction process and excessive smoothing of network outputs, thereby ensuring the adaptive correction process’s correctness. Experimental results demonstrate that our proposed method outperforms random initialization, ImageNet pre-training, and other representation learning methods on a variety of downstream tasks. In particular, when compared to the method that learns representations directly from deviated geographical supervision, it is proved that our method can eliminate the influence of deviations and further improve the effect of representation learning.

High-resolution hyperspectral remote sensing images are of great significance to agricultural, urban, and military applications. However, collecting and labeling hyperspectral images are time-consuming, expensive, and usually heavily rely on domain knowledge. In this article, we propose a new method for generating high-resolution hyperspectral images and subpixel ground-truth annotations from RGB images. Given a single high-resolution RGB image as its conditional input, unlike previous methods that directly predict spectral reflectance and ignores the physics behind it, we consider both imaging mechanism and spectral mixing, introduce a deep generative network that first recovers the spectral abundance for each pixel, and then generate the final spectral data cube with the standard USGS spectral library. In this way, our method not only synthesizes high-quality spectral data existing in the real world but also generates subpixel-level spectral abundance with well-defined spectral reflectance characteristics. We also introduce a spatial discriminative network and a spectral discriminative network to improve the fidelity of the synthetic output from both spatial and spectral perspectives. The whole framework can be trained end-to-end in an adversarial training paradigm. We refer to our method as “Physics-informed Deep Adversarial Spectral Synthesis (PDASS).” On the IEEEgrss_dfc_2018dataset, our method achieves an MPSNR of 47.56 on spectral reconstruction accuracy and outperforms other state-of-the-art methods. As latent variables, the generated spectral abundance and the atmospheric absorption coefficients of sunlight also suggest the effectiveness of our method.

Cloud detection, as an important preprocessing operation for remote sensing (RS) image analysis, has received increasing attention in recent years. Most of the previous cloud detection methods consider the detection as a pixel-wise image classification problem (cloud versus background), which inevitably leads to a category-ambiguity when dealing with the detection of thin clouds. In this article, starting from the RS imaging mechanism on cloud images, we re-examine the cloud detection under a totally different point of view, i.e., to formulate cloud detection as a mixed energy separation between foreground and background images. This process can be further equivalently implemented under a deep learning-based image matting framework with a clear physical significance. More importantly, the proposed method is capable to deal with three different but related tasks, i.e., “cloud detection,” “cloud removal,” and “cloud cover assessment,” under a unified framework. The experimental results on the three satellite image data sets demonstrate the effectiveness of our method, especially for those hard but common examples in RS images, such as the thin and wispy cloud.

The detection and removal of cloud in remote sensing images are essential for earth observation applications. Most previous methods consider cloud detection as a pixel-wise semantic segmentation process (cloud v.s. background), which inevitably leads to a category-ambiguity problem when dealing with semi-transparent clouds. We re-examine the cloud detection under a totally different point of view, i.e. to formulate it as a mixed energy separation process between foreground and background images, which can be equivalently implemented under an image matting paradigm with a clear physical significance. We further propose a generative adversarial framework where the training of our model neither requires any pixel-wise ground truth reference nor any additional user interactions. Our model consists of three networks, a cloud generator G, a cloud discriminator D, and a cloud matting network F, where G and D aim to generate realistic and physically meaningful cloud images by adversarial training, and F learns to predict the cloud reflectance and attenuation. Experimental results on a global set of satellite images demonstrate that our method, without ever using any pixel-wise ground truth during training, achieves comparable and even higher accuracy over other fully supervised methods, including some recent popular cloud detectors and some well-known semantic segmentation frameworks.