Filtering Pseudo-References by Paraphrasing for Automatic Evaluation of Machine Translation

In this paper, we introduce our participation in the WMT 2019 Metric Shared Task. We propose a method to filter pseudo-references by paraphrasing for automatic evaluation of machine translation (MT). We use the outputs of off-the-shelf MT systems as pseudoreferences filtered by paraphrasing in addition to a single human reference (gold reference). We use BERT fine-tuned with paraphrase corpus to filter pseudo-references by checking the paraphrasability with the gold reference. Our experimental results of the WMT 2016 and 2017 datasets show that our method achieved higher correlation with human evaluation than the sentence BLEU (Sent-BLEU) baselines with a single reference and with unfiltered pseudo-references.