Fig 1.
Gradients of network features.
Distribution of discrete gradients of network features at different training stages. (a): The evolution of discrete gradient values for each layer in the network as training iterations (epochs). (b): The changes in discrete gradient values for network layers with skip connections throughout the training iterations (epochs).
Fig 2.
The overall framework of FIAN.
The overall framework of the suggested frequency information-adaptive network for spatial-frequency domain pansharpening(FIAN). FIAFM stands for frequency information-adaptive filter module. Reprinted from https://github.com/liangjiandeng/PanCollection under a CC BY license, with permission from Liangjian Deng, original copyright 2025.
Fig 3.
Schematic diagram of the frequency feature selection strategy.
Schematic illustration of the frequency feature selection approach. (a) The spectrum of discrete gradients for ten randomly chosen GT data. (b) The procedure of identifying features that correspond to the numerical range of the GT discrete gradients and subsequently inputting these selected features into the frequency information-adaptive filter module for additional processing. FIAFM stands for frequency information-adaptive filter module. Reprinted from https://github.com/liangjiandeng/PanCollection under a CC BY license, with permission from Liangjian Deng, original copyright 2025.
Fig 4.
Multi-frequency information fusion module.
The multi-frequency information fusion module amalgamates the results from a quintet of distinct frequency-discriminating filters with the feature output derived by the CNN network. In the schematic diagram, “OUT" represents the output features of the CNN network. FFT stands for Fast Fourier Transform, while IFFT represents the Inverse Fourier Transform.
Table 1.
Quantitative metrics of reduced-resolution WV3 data.
Fig 5.
Visual comparisons of reduced-resolution WV3 data.
The visual comparisons of fusion results from various methods applied to reduced-resolution data from the WorldView-3 satellite. Reprinted from https://github.com/liangjiandeng/PanCollection under a CC BY license, with permission from Liangjian Deng, original copyright 2025.
Table 2.
Quantitative metrics of full-resolution WV3 data.
Fig 6.
Visual comparisons of full-resolution WV3 data.
The visual comparisons of fusion results from various methods applied to full-resolution data from the WorldView-3 satellite. Reprinted from https://github.com/liangjiandeng/PanCollection under a CC BY license, with permission from Liangjian Deng, original copyright 2025.
Table 3.
Quantitative metrics of reduced-resolution WV2 data.
Fig 7.
Visual comparisons of reduced-resolution WV2 data.
The visual comparisons of fusion results from various methods applied to reduced-resolution data from the WV2 satellite. Reprinted from https://github.com/liangjiandeng/PanCollection under a CC BY license, with permission from Liangjian Deng, original copyright 2025.
Table 4.
Quantitative metrics of full-resolution WV2 data.
Fig 8.
Visual comparisons of full-resolution WV2 data.
The visual comparisons of fusion results from various methods applied to full-resolution data from the WV2 satellite. Reprinted from https://github.com/liangjiandeng/PanCollection under a CC BY license, with permission from Liangjian Deng, original copyright 2025.
Table 5.
Quantitative metrics of reduced-resolution QB data.
Fig 9.
Visual comparisons of reduced-resolution QB data.
The visual comparisons of fusion results from various methods applied to reduced-resolution data from the QB satellite. Reprinted from https://github.com/liangjiandeng/PanCollection under a CC BY license, with permission from Liangjian Deng, original copyright 2025.
Table 6.
Quantitative metrics of full-resolution QB data.
Fig 10.
Visual comparisons of full-resolution QuickBird data.
The visual comparisons of fusion results from various methods applied to full-resolution data from the QB satellite. Reprinted from https://github.com/liangjiandeng/PanCollection under a CC BY license, with permission from Liangjian Deng, original copyright 2025.
Table 7.
The ablation protocols for the suggested FIAN approach, in which the frequency information-adaptive filter module is denoted by FIAFM and the multi-frequency information fusion module is symbolized by MFIFM.
Table 8.
Quantitative metrics of ablation methods on reduced-resolution WV3 data.
Fig 11.
Visual comparisons of ablation methods on reduced-resolution WV3 data.
Visual comparisons of the effects from all ablation methods applied to reduced-resolution data from the WorldView-3 satellite. Reprinted from https://github.com/liangjiandeng/PanCollection under a CC BY license, with permission from Liangjian Deng, original copyright 2025.