Robust Open-Vocabulary Translation from Visual Text Representations

Machine translation models have discrete vocabularies and commonly use subword segmentation techniques to achieve an 'open-vocabulary.' This approach relies on consistent and correct underlying unicode sequences, and makes models susceptible to degradation from common types of noise and variation. Motivated by the robustness of human language processing, we propose the use of visual text representations, which dispense with a finite set of text embeddings in favor of continuous vocabularies created by processing visually rendered text. We show that models using visual text representations approach or match performance of text baselines on clean TED datasets. More importantly, models with visual embeddings demonstrate significant robustness to varied types of noise, achieving e.g., 25.9 BLEU on a character permuted German--English task where subword models degrade to 1.9.