OCR Evaluation Tools for the 21st Century

Abstract

We introduce ocreval, a port of the ISRI OCR Evaluation Tools, now with Unicode support. We describe how we upgraded the ISRI OCR Evaluation Tools to support modern text processing tasks. ocreval supports producing character-level and word-level accuracy reports, supporting all characters representable in the UTF-8 character encoding scheme. In addition, we have implemented the Unicode default word boundary specification in order to support word-level accuracy reports for a broad range of writing systems. We argue that character-level and word-level accuracy reports produce confusion matrices that are useful for tasks beyond OCR evaluation—including tasks supporting the study and computational modeling of endangered languages.