Stringalign: Moving beyond summary statistics with a transparent Unicode-aware tool for evaluating automatic transcription models
This work addresses the inconsistency and poor reproducibility of character error rate (CER) and word error rate (WER) metrics in evaluating automatic transcription models, which stem from opaque preprocessing and ambiguous definitions of characters and words in existing text alignment tools. To resolve this, the authors propose Stringalign, a lightweight Python library that introduces FAIR principles to transcription evaluation for the first time. Stringalign enables reproducible, fine-grained error analysis through Unicode-aware transparent normalization, flexible tokenization strategies, and character- and word-level alignment algorithms. Coupled with interactive visualizations, Stringalign significantly enhances evaluation consistency and interpretability across OCR, handwritten text recognition (HTR), and automatic speech recognition (ASR) tasks, thereby facilitating effective model diagnosis and selection.