Figure 1
Visual schema of PageXML (by Tobias Hodel, CC-BY).
Table 1
Results of HTR engines based on small training sets compared with a validation set of known hands.
| WRITING STYLE | HANDS | TOKENS | ENGINE | % CER VAL. | % CER TRAIN. |
|---|---|---|---|---|---|
| Early Modern Kurrent | 1 | 48,277 | HTR+ | 2.87 | 1.11 |
| PyLaia | 4.2 | 4.3 | |||
| Medieval Charter | 3/4 | 77,353 | HTR+ | 5.44 | 2.64 |
| PyLaia | 7.80 | 12.30 |
Table 2
Results of HTR engines based on large training sets comparing results on training set and validation set consisting of a multitude of identical hands (same hands are included in training and validation set).
| WRITING STYLE | HANDS | TOKENS | ENGINE | % CER VAL. | % CER TRAIN. |
|---|---|---|---|---|---|
| German Kurrent 19th century (State Archives Zürich) | ~12 | 147,608 | HTR+ | 2.55 | 3.12 |
| PyLaia | 3.31 | 2.90 | |||
| German Kurrent 19th century (large) | unknown | 26,026,908 | HTR+ | 1.73 | 3.41 |
Table 3
Comparing different large HTR models and engines, applying the introduced test set, independent of already known hands.
| HTR MODEL | HTR ENGINE | CER MEAN % | CER MEDIAN % | CER UPPER BOUND (WORST) |
|---|---|---|---|---|
| German Kurrent M2 | HTR+ | 3.43 | 2.76 | 9.13 |
| PyLaia | 18.77 | 13.30 | 51.05 | |
| Transkribus German Kurrent | HTR+ | 5.90 | 4.85 | 10.20 |
| RRB | HTR+ | 9.15 | 8.13 | 16.28 |
Figure 2
Visual impressions of the test set. Transcription of the sample line (middle line): Washington unterm 27. Juni mit, daß laut Anzeige.