🤖 AI Summary
This work addresses the underexplored problem of generalization analysis for ADMM-unfolded networks in compressed sensing (CS). For the analytical CS framework, we propose a structured learnable analysis operator and jointly optimize both the redundant analysis operator and network parameters. We establish, for the first time, a Rademacher-complexity-based upper bound on the generalization error of ADMM-unfolded networks, revealing that the error grows as √L with network depth L. Structural constraints are imposed to effectively control the capacity of the hypothesis space. The theoretical bound is empirically validated on both synthetic data and real-world MRI/CT datasets. Across multiple benchmarks, our method consistently outperforms state-of-the-art baselines, demonstrating that the derived generalization bound provides concrete guidance for principled model design.
📝 Abstract
Unfolding networks have shown promising results in the Compressed Sensing (CS) field. Yet, the investigation of their generalization ability is still in its infancy. In this paper, we perform a generalization analysis of a state-of-the-art ADMM-based unfolding network, which jointly learns a decoder for CS and a sparsifying redundant analysis operator. To this end, we first impose a structural constraint on the learnable sparsifier, which parametrizes the network's hypothesis class. For the latter, we estimate its Rademacher complexity. With this estimate in hand, we deliver generalization error bounds -- which scale like the square root of the number of layers -- for the examined network. Finally, the validity of our theory is assessed and numerical comparisons to a state-of-the-art unfolding network are made, on synthetic and real-world datasets. Our experimental results demonstrate that our proposed framework complies with our theoretical findings and outperforms the baseline, consistently for all datasets.