Exchanging image processing and OCR components in a Setswana digitisation pipeline
As more natural language processing (NLP) applications benefit from neural network based approaches, it makes sense to re-evaluate existing work in NLP. A complete pipeline for digitisation includes several components hand- ling the material in sequence. Image processing after scanning the document...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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South African Institute of Computer Scientists and Information Technologists
2020-12-01
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| Series: | South African Computer Journal |
| Subjects: | |
| Online Access: | https://sacj.cs.uct.ac.za/index.php/sacj/article/view/707 |
| Summary: | As more natural language processing (NLP) applications benefit from neural network based approaches, it makes sense to re-evaluate existing work in NLP. A complete pipeline for digitisation includes several components hand- ling the material in sequence. Image processing after scanning the document has been shown to be an important factor in final quality. Here we compare two different approaches for visually enhancing documents before Op- tical Character Recognition (OCR), (1) a combination of ImageMagick and Unpaper and (2) OCRopus. We also compare Calamari, a new line-based OCR package using neural networks, with the well-known Tesseract 3 as the OCR component. Our evaluation on a set of Setswana documents reveals that the combination of ImageMa- gick/Unpaper and Calamari improves on a current baseline based on Tesseract 3 and ImageMagick/Unpaper with over 30%, achieving a mean character error rate of 1.69 across all combined test data. |
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| ISSN: | 1015-7999 2313-7835 |