Low Spatial Resolution Hyperspectral Image Research Articles

Unsupervised multi-level spatio-spectral fusion transformer for hyperspectral image super-resolution

Fusing a low spatial resolution hyperspectral image (LR-HSI) with a high spatial resolution multispectral image (HR-MSI) is widely used for HSI super-resolution. Recent works still face problems in exploring global spatio-spectral correlation and lack effective utilization of multi-level features of the inputs (i.e., HR-MSI and LR-HSI), which results in a lack of similarity between the reconstruction and the inputs, ultimately causing significant spatio-spectral distortion. To solve these problems, we design an Unsupervised Multi-level Spatio-spectral Fusion Transformer (UMSFT). In UMSFT, a novel multi-level features fusion strategy is constructed, which fuses the hierarchy features of the inputs via proposed Spatio-spectral Feature Fusion Attention Blocks (S2F-FAB) in a level-by-level manner, thereby fully exploring the interaction between the hierarchical features. The S2F-FAB is specially designed for HSI-MSI fusion consisting of two components: (1) a spatial fusion module (Spa-FM) is designed for spatial domain fusion, and its output is set as Values (V) of a transformer; (2) a novel spectral feature cross attention (Spe- FCA) formulates the features of LR-HSI and HR-MSI as Queries (Q) and Keys (K), respectively, and achieves spectral domain fusion by applying attention mechanism along the spectral dimension. Incorporating spatial detail reconstruction and spectral feature integration into the attention mechanism, the S2F-FAB efficiently exploits the spatio-spectral correlation between target HR-HSI and inputs. Experimental results on three public datasets and our real-world images show the superiority of our method as compared with eleven state-of-the-art methods. Codes will be available at https://github.com/Caoxuheng/HIFtool.

Semi-blind hyperspectral and multispectral image fusion via generalized inverse matrix optimization

Combining a low spatial resolution hyperspectral image (HSI) with a high spatial resolution multispectral image (MSI) is an economical way to obtain a high spatial resolution hyperspectral image (HR-HSI). However, existing fusion methods often rely on a critical variable, the point spread function (PSF), which is difficult to obtain in practice. Additionally, these methods often require a long fusion time and have many parameters that need re-debugging on different datasets to achieve satisfactory results. Many existing methods lack robustness in handling complex scenarios, such as complex PSF, changing spatial downsampling factors, and large-scale datasets. These issues can result in degraded performance or render the methods inapplicable to practical scenarios. Therefore, we propose an efficient and parameterless semi-blind fusion method based on generalized inverse matrix optimization (GIMO), which is robust for multiple complex situations. Our method uses the definition of generalized inverse matrix and the relationship among HSI, MSI, and HR-HSI to approximate the function module of PSF. Then, we calculate the generalized inverse matrix of the spectral response function (SRF). Finally, we optimize the generalized inverse matrix of SRF using the Sylvester equation and multiply it with MSI to obtain HR-HSI. This is the first proposed method to achieve hyperspectral image super-resolution by optimizing the inverse matrix of the spectral response function. Experiments on multiple simulated datasets and one real dataset have validated that our GIMO method outperforms existing state-of-the-art methods, especially regarding fusion time and robustness for various complex scenarios.

CS2DIPs: Unsupervised HSI Super-Resolution Using Coupled Spatial and Spectral DIPs.

In recent years, fusing high spatial resolution multispectral images (HR-MSIs) and low spatial resolution hyperspectral images (LR-HSIs) has become a widely used approach for hyperspectral image super-resolution (HSI-SR). Various unsupervised HSI-SR methods based on deep image prior (DIP) have gained wide popularity thanks to no pre-training requirement. However, DIP-based methods often demonstrate mediocre performance in extracting latent information from the data. To resolve this performance deficiency, we propose a coupled spatial and spectral deep image priors (CS2DIPs) method for the fusion of an HR-MSI and an LR-HSI into an HR-HSI. Specifically, we integrate the nonnegative matrix-vector tensor factorization (NMVTF) into the DIP framework to jointly learn the abundance tensor and spectral feature matrix. The two coupled DIPs are designed to capture essential spatial and spectral features in parallel from the observed HR-MSI and LR-HSI, respectively, which are then used to guide the generation of the abundance tensor and spectral signature matrix for the fusion of the HSI-SR by mode-3 tensor product, meanwhile taking some inherent physical constraints into account. Free from any training data, the proposed CS2DIPs can effectively capture rich spatial and spectral information. As a result, it exhibits much superior performance and convergence speed over most existing DIP-based methods. Extensive experiments are provided to demonstrate its state-of-the-art overall performance including comparison with benchmark peer methods.

Hyperspectral Image Super-Resolution via Adaptive Factor Group Sparsity Regularization-Based Subspace Representation

Hyperspectral image (HSI) super-resolution is a vital technique that generates high spatial-resolution HSI (HR-HSI) by integrating information from low spatial-resolution HSI with high spatial-resolution multispectral image (MSI). However, existing subspace representation-based methods face challenges, including adaptive subspace dimension determination, inadequate spectral correlation capture, and expensive computation. In this paper, we propose a novel factor group sparsity regularized subspace representation (FGSSR)-based method for HSI super-resolution that can simultaneously address these issues encountered in previous methods. Specifically, by incorporating the factor group sparsity regularization into the subspace representation model, we first propose an FGSSR model to capture the spectral correlation property of the HR-HSI. The key advantage of FGSSR lies in its equivalence to the Schatten-p norm and its adaptive determination of the accurate subspace dimension, enabling it to capture spectral correlation more effectively. To preserve the spatial self-similarity prior in the HR-HSI, the tensor nuclear norm regularization on the low-dimensional coefficients is also incorporated into the proposed FGSSR-based model. Finally, an effective proximal alternating minimization-based algorithm is developed to solve the FGSSR-based model. Experimental results on the simulated and real datasets demonstrate that the proposed FGSSR-based method outperforms several state-of-the-art fusion methods with significant improvements.

Multispectral and hyperspectral image fusion based on low-rank unfolding network

Recently, deep unfolding networks (DUNs) have been applied to the fusion of low spatial resolution hyperspectral (LR HS) and high spatial resolution multispectral (HR MS) images and achieved satisfactory high spatial resolution hyperspectral (HR HS) images. However, the low-rank and sparse priors in these networks are not exploited sufficiently. In this paper, we establish an LR HS and HR MS image fusion model based on robust principal component analysis (RPCA), which simultaneously captures the low-rank and sparse properties in HS images. Then, the fusion model is optimized with the alternating direction method of multipliers (ADMM). To make full use of the representation capacity of DUNs, we unfold the derived ADMM algorithm as a network, named low-rank unfolding network (LRU-Net). Specifically, each iteration in ADMM is unfolded as one stage in LRU-Net, in which the low-rank and sparse priors are learned by singular value thresholding (SVT) and sparse module, respectively. Finally, all features from all stages are integrated to produce the desired HR HS image. Three benchmark datasets were chosen for comparison to demonstrate the effectiveness of the proposed LRU-Net. The experimental results demonstrate that LRU-Net performs better in terms of both qualitative and quantitative results compared to state-of-the-art fusion methods. The source code is publicly available at https://github.com/RSMagneto/LRU-Net.

Hyperspectral image super-resolution via spectral matching and correction.

Fusing a low-spatial-resolution hyperspectral image (LR-HSI) and a high-spatial-resolution RGB image (HR-RGB) is an important technique for HR-HSI obtainment. In this paper, we propose a dual-illuminance fusion-based super-resolution method consisting of spectral matching and correction. In the spectral matching stage, an LR-HSI patch is first searched for each HR-RGB pixel; with the minimum color difference as a constraint, the matching spectrum is constructed by linear mixing the spectrum in the HSI patch. In the spectral correlation stage, we establish a polynomial model to correct the matched spectrum with the aid of the HR-RGBs illuminated by two illuminances, and the target spectrum is obtained. All pixels in the HR-RGB are traversed by the spectral matching and correction process, and the target HR-HSI is eventually reconstructed. The effectiveness of our method is evaluated on three public datasets and our real-world dataset. Experimental results demonstrate the effectiveness of our method compared with eight fusion methods.

Universal high spatial resolution hyperspectral imaging using hybrid-resolution image fusion

By fusing a low spatial resolution hyperspectral image (LR-HSI) and a high spatial resolution RGB image (HR-RGB), hybrid-resolution hyperspectral imaging has been a popular framework for acquiring high spatial resolution hyperspectral images (HR-HSIs). Existing fusion methods always employ a known spectral response function (SRF) of the RGB camera to reconstruct the HR-HSI. The SRF is often limited or unavailable in practice, restricting the performance of existing methods. To address this problem, we propose a color space transfer-based fusion strategy that obtains HR-HSIs based on a hybrid resolution hyperspectral imaging system without measuring the SRF. Specifically, using a clustered-based backpropagation neural network, the HR-RGB is mapped into the CIE XYZ color space, and the HR-XYZ is obtained. In the CIE XYZ color space, its SRF is known; thus, the the SRF measurement is successfully skipped. To efficiently fuse the HR-XYZ and the LR-HSI, we propose a polynomial fusion model that estimates the ratio matrix between the target HR-HSI and the upsampled LR-HSI. Finally, the target HR-HSI is reconstructed by combining the ratio matrix and the unsampled LR-HSI. Experimental results on two public data sets and our real-world data sets show that the proposed method outperforms five state-of-the-art fusion methods.

Enhanced Deep Blind Hyperspectral Image Fusion.

The goal of hyperspectral image fusion (HIF) is to reconstruct high spatial resolution hyperspectral images (HR-HSI) via fusing low spatial resolution hyperspectral images (LR-HSI) and high spatial resolution multispectral images (HR-MSI) without loss of spatial and spectral information. Most existing HIF methods are designed based on the assumption that the observation models are known, which is unrealistic in many scenarios. To address this blind HIF problem, we propose a deep learning-based method that optimizes the observation model and fusion processes iteratively and alternatively during the reconstruction to enforce bidirectional data consistency, which leads to better spatial and spectral accuracy. However, general deep neural network inherently suffers from information loss, preventing us to achieve this bidirectional data consistency. To settle this problem, we enhance the blind HIF algorithm by making part of the deep neural network invertible via applying a slightly modified spectral normalization to the weights of the network. Furthermore, in order to reduce spatial distortion and feature redundancy, we introduce a Content-Aware ReAssembly of FEatures module and an SE-ResBlock model to our network. The former module helps to boost the fusion performance, while the latter make our model more compact. Experiments demonstrate that our model performs favorably against compared methods in terms of both nonblind HIF fusion and semiblind HIF fusion.

Hyperspectral Image Super-Resolution Network Based on Cross-Scale Nonlocal Attention

Hyperspectral image (HSI) super-resolution generally means the fusion of low-spatial resolution hyperspectral image (LRHSI) and high-spatial resolution multi-spectral (MSI)/panchromatic (PAN) image (HRMPI) to get high-spatial resolution HSI (HRHSI). Existing fusion methods have not sufficiently considered the huge spectral and spatial resolution difference between the LRHSI and HRMPI. In addition, most DL-based methods that adopt the CNN structure are limited by its local feature learning, and it is difficult to exploit the global dependency of image features. To fully adapt to the huge modality difference between LRHSI and HRMPI and release the limitation of local feature learning, we design the cross spectral-scale and shift-window based cross spatial-scale non-local attention networks (CSSNet) to effectively fuse the LRHSI and HRMPI. These two networks could explicitly learn the spectral and spatial correlations between two input images. These correlations are then used to reconstruct the HRHSI feature, which makes the obtained HRHSI feature to maintain the spectral and spatial feature consistency with the input images. Finally, a ‘feature aggregation module’ is designed to aggregate the image features from these two networks and output the fused HRHSI. Extensive experimental results on both HM-fusion (fusion with MSI) and HP-fusion (fusion with PAN image) tasks demonstrate CSSNet’s state-of-the-art (SOTA) performance compared to other fusion methods. (The codes could be available at https://github.com/rs-lsl/CSSNet).

Hyperspectral Image Super-resolution via Knowledge-Driven Deep Unrolling and Transformer Embedded Convolutional Recurrent Neural Network.

Hyperspectral (HS) imaging has been widely used in various real application problems. However, due to the hardware limitations, the obtained HS images usually have low spatial resolution, which could obviously degrade their performance. Through fusing a low spatial resolution HS image with a high spatial resolution auxiliary image (e.g., multispectral, RGB or panchromatic image), the so-called HS image fusion has underpinned much of recent progress in enhancing the spatial resolution of HS image. Nonetheless, a corresponding well registered auxiliary image cannot always be available in some real situations. To remedy this issue, we propose in this paper a newly single HS image super-resolution method based on a novel knowledge-driven deep unrolling technique. Precisely, we first propose a maximum a posterior based energy model with implicit priors, which can be solved by alternating optimization to determine an elementary iteration mechanism. We then unroll such iteration mechanism with an ingenious Transformer embedded convolutional recurrent neural network in which two structural designs are integrated. That is, the vision Transformer and 3D convolution learn the implicit spatial-spectral priors, and the recurrent hidden connections over iterations model the recurrence of the iterative reconstruction stages. Thus, an effective knowledge-driven, end-to-end and data-dependent HS image super-resolution framework can be successfully attained. Extensive experiments on three HS image datasets demonstrate the superiority of the proposed method over several state-of-the-art HS image super-resolution methods.

Hyperspectral Multispectral Image Fusion via Fast Matrix Truncated Singular Value Decomposition

Recently, methods for obtaining a high spatial resolution hyperspectral image (HR-HSI) by fusing a low spatial resolution hyperspectral image (LR-HSI) and high spatial resolution multispectral image (HR-MSI) have become increasingly popular. However, most fusion methods require knowing the point spread function (PSF) or the spectral response function (SRF) in advance, which are uncertain and thus limit the practicability of these fusion methods. To solve this problem, we propose a fast fusion method based on the matrix truncated singular value decomposition (FTMSVD) without using the SRF, in which our first finding about the similarity between the HR-HSI and HR-MSI is utilized after matrix truncated singular value decomposition (TMSVD). We tested the FTMSVD method on two simulated data sets, Pavia University and CAVE, and a real data set wherein the remote sensing images are generated by two different spectral cameras, Sentinel 2 and Hyperion. The advantages of FTMSVD method are demonstrated by the experimental results for all data sets. Compared with the state-of-the-art non-blind methods, our proposed method can achieve more effective fusion results while reducing the fusing time to less than 1% of such methods; moreover, our proposed method can improve the PSNR value by up to 16 dB compared with the state-of-the-art blind methods.

A Lightweight Multi-Level Information Network for Multispectral and Hyperspectral Image Fusion

The process of fusing the rich spectral information of a low spatial resolution hyperspectral image (LR-HSI) with the spatial information of a high spatial resolution multispectral image (HR-MSI) to obtain an HSI with the spatial resolution of an MSI image is called hyperspectral image fusion (HIF). To reconstruct hyperspectral images at video frame rate, we propose a lightweight multi-level information network (MINet) for multispectral and hyperspectral image fusion. Specifically, we develop a novel lightweight feature fusion model, namely residual constraint block based on global variance fine-tuning (GVF-RCB), to complete the feature extraction and fusion of hyperspectral images. Further, we define a residual activity factor to judge the learning ability of the residual module, thereby verifying the effectiveness of GVF-RCB. In addition, we use cascade cross-level fusion to embed the different spectral bands of the upsampled LR-HSI in a progressive manner to compensate for lost spectral information at different levels and to maintain spatial high frequency information at all times. Experiments on different datasets show that our MINet outperforms the state-of-the-art methods in terms of objective metrics, in particular by requiring only 30% of the running time and 20% of the number of parameters.

Hyperspectral image super-resolution using cluster-based deep convolutional networks

In recent years, deep convolutional neural networks (CNNs) have been widely exploited for the hyperspectral image (HSI) super-resolution and obtained remarkable performance. However, most of the existing CNN-based methods have two main problems. One is to use two-dimension (2D) convolution to extract spatial information without paying attention to the mining of spectral information of hyperspectral images. The other is to use three-dimension (3D) convolution, which reduces the efficiency of the model when the network parameters increase. To address the above issues, we propose clustering deep residual neural network (CDRNN) for hyperspectral image super-resolution in this paper. The proposed CDRNN learns the complex, nonlinear mappings between low spatial resolution HSI and high spatial resolution HSI. At first, an unsupervised clustering method is used to divide a low spatial resolution HSI into several classes according to spectral correlation. Then, the spectrum-pairs from the classified low spatial resolution HSI and the corresponding high spatial resolution HSI are used to train the CDRNN to establish the nonlinear mapping for each class. Finally, we classify the given low spatial resolution HSI into the determined category and use the trained CDRNN to reconstruct the final high spatial resolution HSI from the classified low spatial resolution HSI. We conduct extensive experiments on three simulated benchmark datasets and a real HSI to evaluate the super-resolution performance of the proposed method. Experimental results show that our proposed method achieves significant improvement over state-of-the-art methods.

Hyperspectral image super-resolution via a multi-stage scheme without employing spatial degradation.

Recently, it has become popular to obtain a high spatial resolution hyperspectral image (HR-HSI) by fusing a low spatial resolution hyperspectral image (LR-HSI) with a high spatial resolution RGB image (HR-RGB). Existing HSI super-resolution methods are designed based on a known spatial degeneration. In practice, it is difficult to obtain correct spatial degradation, which restricts the performance of existing methods. Therefore, we propose a multi-stage scheme without employing the spatial degradation model. The multi-stage scheme consists of three stages: initialization, modification, and refinement. According to the angle similarity between the HR-RGB pixel and LR-HSI spectra, we first initialize a spectrum for each HR-RGB pixel. Then, we propose a polynomial function to modify the initialized spectrum so that the RGB color values of the modified spectrum are the same as the HR-RGB. Finally, the modified HR-HSI is refined by a proposed optimization model, in which a novel, to the best of our knowledge, spectral-spatial total variation (SSTV) regularizer is investigated to keep the spectral and spatial structure of the reconstructed HR-HSI. The experimental results on two public datasets and our real-world images demonstrate our method outperforms eight state-of-the-art existing methods in terms of both reconstruction accuracy and computational efficiency.

A model-guided deep convolutional sparse coding network for hyperspectral and multispectral image fusion

ABSTRACT Although high-resolution hyperspectral images are of great significance in various applications, the manner in which to acquire such images remains a fundamental problem due to sensors’ physical limitations. Fusing high-spatial resolution multispectral images (HR-MSIs) with low-spatial resolution hyperspectral images (LR-HSIs) has become a common approach to increase the spatial resolution of hyperspectral images (HSIs). Various fusion methods have been developed to obtain images with high resolution in both the spatial and spectral domains; the main drawbacks of these methods are time consumption and spectral distortion. With the intention of developing a fast yet accurate image fusion algorithm, this paper is attempted to incorporate the benefits of deep learning and convolutional sparse coding to create a new fusion method. First, the inputs are initialized by solving the Sylvester equation from an up-sampled LR-HSI and an HR-MSI. Second, the learned iterative shrinkage thresholding algorithm is extended to its convolutional version as the central part of the model and recursively learn the sparse priors. Finally, a fused image is achieved by adding the residual to the initialized image. The proposed method is conducted on the widely used datasets (Harvard and iCVL). The experimental results are demonstrated that the proposed approach outperforms several state-of-the-art approaches in terms of quantitative and qualitative perspectives.

Deep Multiscale Feedback Network for Hyperspectral Image Fusion

Hyperspectral imaging is useful in many remote sensing tasks. However, it is often challenging to obtain high-resolution images in both the spatial and spectral domains due to hardware limitations. Hyperspectral image fusion (HIF) solves this problem by fusing a low spatial resolution hyperspectral image (LR-HSI) and a high spatial resolution multispectral images (HR-MSI) to obtain a high spatial resolution hyperspectral image (HR-HSI). Many methods have been proposed for HIF, but few approaches have explored the multiscale mutual dependencies between LR-HSI, HR-MSI, and HR-HSI. This kind of mutual dependencies come from the fact that LR-HSI, HR-MSI, and HR-HSI capture the same scene with different spatial or spectral resolutions. To this end, we propose a deep multiscale feedback network (DMFBN) that iteratively learns image fusion and degeneration for HIF. We further equip the network with an error feedback mechanism coupled with multiscale feature learning. Both strategies help better learn the mutual dependencies. Extensive quantitative and qualitative evaluations on two public datasets show that the proposed method performs favorably against the state-of-the-art (SOTA) methods.

Integrated Fusion for Panchromatic, Multispectral, Hyperspectral Remote Sensing Images With Different Swath Widths

Zi Yuan (ZY)-1 02D satellite simultaneously provides the low spatial resolution (LR) and narrow swath-width hyperspectral (HS) image, the moderate spatial resolution (MR) multispectral (MS) image with a wider swath width, and the high spatial resolution (HR) panchromatic (PAN) image with the same wide swath width to the MR MS. How to comprehensively integrate their complementary advantages to obtain the wide swath-width and high-fidelity HR HS image is interesting but challenging. In this paper, we propose an integrated fusion method for the HR PAN, MR MS, and LR HS images with different swath widths, to generate the optimal wide swath-width HR HS image. The proposed method is based on the encoder-decoder learning framework. In the proposed fusion framework, a novel multi-branch encoder structure with an enhanced HS-encoder module and the multilevel spatial-spectral aggregation block is designed, by considering the difference in the spatial and spectral resolution among the multi-sensor images. The experiments on synthetic and real datasets from both qualitative and quantitative aspects demonstrated the competitive performance of the proposed method.

Unmixing-Based PAN-Guided Fusion Network for Hyperspectral Imagery

The hyperspectral image (HSI) has been widely used in many applications due to its fruitful spectral information. However, the limitation of imaging sensors has reduced its spatial resolution that causes detail loss. One solution is to fuse the low spatial resolution HSI (LR-HSI) and the panchromatic (PAN) image with inverse features to get the high-resolution HSI (HR-HSI). Most of the existing fusion methods just focus on small fusion ratios like 4 or 6, which might be impractical for some large ratios’ HSI and PAN image pairs. Moreover, the ill-posedness of restoring detail information in HSI with hundreds of bands from PAN image with only one band has not been solved effectively, especially under large fusion ratios. Therefore, a lightweight unmixing-based PAN-guided fusion network (Pgnet) is proposed to mitigate this ill-posedness and improve the fusion performance significantly. Note that the fusion process of the proposed network is under the projected low-dimensional abundance subspace with an extremely large fusion ratio of 16. Furthermore, based on the linear and nonlinear relationships between the PAN intensity and abundance, an interpretable PAN detail inject network (PDIN) is designed to inject the PAN details into the abundance feature efficiently. Comprehensive experiments on simulated and real datasets demonstrate the superiority and generality of our method over several state-of-the-art (SOTA) methods qualitatively and quantitatively (the codes in pytorch and paddle versions and dataset could be available at <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/rs-lsl/Pgnet</uri> ).

Hyperspectral and Multispectral Image Fusion Using Factor Smoothed Tensor Ring Decomposition

Fusing a pair of low-spatial-resolution hyperspectral image (LR-HSI) and high-spatial-resolution multispectral image (HR-MSI) has been regarded as an effective and economical strategy to achieve HR-HSI, which is essential to many applications. Among existing fusion models, the tensor ring (TR) decomposition-based model has attracted rising attention due to its superiority in approximating high-dimensional data compared to other traditional matrix/tensor decomposition models. Unlike directly estimating HR-HSI in traditional models, the TR fusion model translates the fusion procedure into an estimate of the TR factor of HR-HSI, which can efficiently capture the spatial–spectral correlation of HR-HSI. Although the spatial–spectral correlation has been preserved well by TR decomposition, the spatial–spectral continuity of HR-HSI is ignored in existing TR decomposition models, sometimes resulting in poor quality of reconstructed images. In this article, we introduce a factor smoothed regularization for TR decomposition to capture the spatial–spectral continuity of HR-HSI. As a result, our proposed model is called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">factor smoothed TR decomposition</i> model, dubbed <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FSTRD</i> . In order to solve the suggested model, we develop an efficient proximal alternating minimization algorithm. A series of experiments on four synthetic datasets and one real-world dataset show that the quality of reconstructed images can be significantly improved by the introduced factor smoothed regularization, and thus, the suggested method yields the best performance by comparing it to state-of-the-art methods.

Edge-Conditioned Feature Transform Network for Hyperspectral and Multispectral Image Fusion

Despite recent advances achieved by deep learning techniques in the fusion of low-spatial-resolution hyperspectral image (LR-HSI) and high-spatial-resolution multispectral image (HR-MSI), it remains a challenge to reconstruct the high-spatial-resolution HSI (HR-HSI) with more accurate spatial details and less spectral distortions, since the low-level structure information such as sharp edges tends to be weakened or lost as the network depth grows. To tackle this issue, we creatively propose an edge-conditioned feature transform network (EC-FTN) in this article, which is mainly composed of three parts, namely, feature extraction network (FEN), feature fusion and transformation network (FFTN), and image reconstruction network (IRN). First, two computationally efficient FENs with 3-D convolutions and reshaping layers are employed to extract the joint spectral-spatial features of input images. Then, the FFTN conditioned on the edge map prior can fuse and transform the features adaptively, in which a fusion node and several cascaded feature modulation modules (FMMs) equipped with feature-wise modulation layers are constructed. Specifically, the edge map is generated via transfer learning, i.e., by applying the Sobel operator to feature maps of the red-green-blue (RGB) version of HR-MSI resulting from the pretrained VGG16 model without extra training. Finally, the desired HR-HSI is recovered from the transformed features through IRN. Furthermore, we elaborately design a weighted combinatorial loss function consisting of mean absolute error, image gradient difference, and spectral angle terms to guide the training. Experiments on both ground-based and remotely sensed datasets demonstrate that our EC-FTN outperforms state-of-the-art methods in visual and quantitive evaluations, as well as in fine details reconstruction.