Overcoming Noisy Labels in Federated Learning Through Local Self-Guiding

Federated Learning (FL) is a privacy-preserving machine learning paradigm that enables clients such as Internet of Things (IoT) devices, and smartphones, to train a high-performance global model jointly. However, in real-world FL deployments, carefully human-annotated labels are expensive and time-consuming. So the presence of incorrect labels (noisy labels) in the local training data of the clients is inevitable, which will cause the performance degradation of the global model. To tackle this problem, we propose a simple but effective method Local Self-Guiding (LSG) to let clients guide themselves during training in the presence of noisy labels. Specifically, LSG keeps the model from memorizing noisy labels by enhancing the confidence of model predictions. Meanwhile, it utilizes the knowledge from local historical models which haven't fit noisy patterns to extract potential ground truth labels of samples. To keep the knowledge without storing models, LSG records the exponential moving average (EMA) of model output logits at different local training epochs as self-ensemble logits on clients' devices, which will lead to negligible computation and storage overhead. Then logit-based knowledge distillation is conducted to guide the local training. Experiments on MNIST, Fashion-MNIST, CIFAR-10, ImageNet-100 with multiple noise levels, and an unbalanced noisy dataset, Clothing1M, demonstrate the resistance of LSG to noisy labels. The code of LSG is available at https://github.com/DaokuanBai/LSG-Main