Arbitrary-scale Fusion Neural Operator

Spatial-spectral fusion offers a promising alternative to expensive equipment in high-resolution hyperspectral (HrHs) imaging. However, training separate models for different scaling factors remains costly. To address this, we propose the Arbitrary-scale Fusion Neural Operator (AFNO), a lightweight solution for HrHs fusion across arbitrary scalings. Instead of entities, AFNO treats low-resolution hyperspectral (LrHs) and high-resolution multispectral (HrMs) images as functions and performs meticulously designed integrations as the mapping operator. The key components include Attention-Driven Convolution Integration (ADCI) to restore discretization invariance disrupted by convolutions, Implicit Neural Functional Integration (INFI) for cross-domain interaction of spatial degradations, and Galerkin-type Integration as a decoder for high-frequency details. Additionally, the bonded activation opeartor are improved for the principle of continuous-discrete equivalence. Extensive experiments validate the superiority of our approach over cutting-edge methods. Notably, AFNO holds significantly better generalization on arbitrary scaling factors, yet requiring only 0.07M parameters.