Retro: Reusing teacher projection head for efficient embedding distillation on Lightweight Models via Self-supervised Learning

Self-supervised learning (SSL) is gaining attention for its ability to learn effective representations with large amounts of unlabeled data. Lightweight models can be distilled from larger self-supervised pre-trained models using contrastive and consistency constraints. Still, the different sizes of the projection heads make it challenging for students to mimic the teacher’s embedding accurately. We propose $\text{textsc}Retro$, which reuses the teacher’s projection head for students, and our experimental results demonstrate significant improvements over the state-of-the-art on all lightweight models. For instance, when training EfficientNet-B0 using ResNet-50/101/152 as teachers, our approach improves the linear result on ImageNet to $66.9\mathrm{\%}$, $69.3\mathrm{\%}$, and $69.8\mathrm{\%}$, respectively, with significantly fewer parameters.