  Continual learning is a challenging problem in which models need to be
trained on non-stationary data across sequential tasks for class-incremental
learning. While previous methods have focused on using either regularization or
rehearsal-based frameworks to alleviate catastrophic forgetting in image
classification, they are limited to a single modality and cannot learn compact
class-aware cross-modal representations for continual audio-visual learning. To
address this gap, we propose a novel class-incremental grouping network (CIGN)
that can learn category-wise semantic features to achieve continual
audio-visual learning. Our CIGN leverages learnable audio-visual class tokens
and audio-visual grouping to continually aggregate class-aware features.
Additionally, it utilizes class tokens distillation and continual grouping to
prevent forgetting parameters learned from previous tasks, thereby improving
the model's ability to capture discriminative audio-visual categories. We
conduct extensive experiments on VGGSound-Instruments, VGGSound-100, and
VGG-Sound Sources benchmarks. Our experimental results demonstrate that the
CIGN achieves state-of-the-art audio-visual class-incremental learning
performance. Code is available at https://github.com/stoneMo/CIGN.
