MRN: Multiplexed Routing Network for Incremental Multilingual Text Recognition

Traditional Multilingual Text Recognition (MLTR) usually targets a fixed set of languages and thus struggles to handle newly added languages or adapt to ever-changing class distributions. In this paper, we introduce the Incremental Multilingual Text Recognition (IMLTR) task in the incremental learning setting, where new language data comes in batches. Compared to generic incremental learning, IMLTR is even more challenging as it suffers from rehearsal-imbalance (uneven distribution of sample characters in the rehearsal set). To address this issue, we propose a Multiplexed Routing Network (MRN), where a series of recognizers is trained for each language. Subsequently, a language predictor is adopted to weigh the recognizers for voting. Since the recognizers are derived from the original model, MRN effectively reduces the reliance on older data and is better suited for rehearsal-imbalance. We extensively evaluate MRN on MLT17 and MLT19 datasets, outperforming existing state-of-the-art methods by a large margin, i.e., accuracy improvement ranging from 10.3% to 27.4% under different settings.