Diffusion-Guided Semantic Consistency for Multimodal Heterogeneity

TL;DR

SemanticFL introduces a diffusion model-based semantic guidance framework for federated learning, effectively addressing non-IID data challenges in multimodal perception and improving model accuracy across benchmarks.

Contribution

It leverages pre-trained diffusion models to create a shared semantic space, enhancing client heterogeneity handling in federated learning with a novel consistency mechanism.

Findings

Achieves up to 5.49% accuracy improvement over FedAvg.

Effective in diverse heterogeneity scenarios.

Validates robustness on CIFAR-10, CIFAR-100, TinyImageNet.

Abstract

Federated learning (FL) is severely challenged by non-independent and identically distributed (non-IID) client data, a problem that degrades global model performance, especially in multimodal perception settings. Conventional methods often fail to address the underlying semantic discrepancies between clients, leading to suboptimal performance for multimedia systems requiring robust perception. To overcome this, we introduce SemanticFL, a novel framework that leverages the rich semantic representations of pre-trained diffusion models to provide privacy-preserving guidance for local training. Our approach leverages multi-layer semantic representations from a pre-trained Stable Diffusion model (including VAE-encoded latents and U-Net hierarchical features) to create a shared latent space that aligns heterogeneous clients, facilitated by an efficient client-server architecture that offloads heavy computation to the server. A unified consistency mechanism, employing cross-modal contrastive learning, further stabilizes convergence. We conduct extensive experiments on benchmarks including CIFAR-10, CIFAR-100, and TinyImageNet under diverse heterogeneity scenarios. Our results demonstrate that SemanticFL surpasses existing federated learning approaches, achieving accuracy gains of up to 5.49% over FedAvg, validating its effectiveness in learning robust representations for heterogeneous and multimodal data for perception tasks.