Leveraging Frequency Analysis for Image Denoising Network Pruning

As a common model compression technique, network pruning is widely used to reduce storage and computational cost of deep models in the resource-constrained regime. However, most current pruning methods are designed for high-level vision tasks, with few developed for low-level vision tasks. We observed that the norm-based pruning criterion, originally designed for high-level vision tasks, is highly unsuitable for low-level image denoising networks. This difference arises because image denoising networks pursue distinct feature granularities and goals compared to typical high-level vision tasks. To address this issue, we propose a novel filter evaluation method, termed High-Frequency Components Pruning (HFCP), specifically tailored for image denoising network pruning. HFCP assesses filter importance based on high-frequency components. To the best of our knowledge, this is the first pruning method designed specifically for image denoising tasks, straightforward and applicable to various types of noise. Furthermore, HFCP enhances the pruned model's high-frequency information content with high reliability and interpretability. This facilitates the network's ability to distinguish high-frequency signals from noise. We comprehensively analyzed multiple image denoising networks and validated HFCP's effectiveness across four mainstream networks.