Presentation of an aligner for ground truth transcriptions with images during the Impact Centre of Competence Annual General Meeting 2015

1. Aligning images with ground truth transcriptions
Rafael C. Carrasco (carrasco@ua.es)
Departamento de Lenguajes y Sistemas Informáticos

2. Impact Ground Truth
Over 30.000 pages of high-quality transcriptions.
difinicion à lo difinido: y antes de contarla, no dexè
dicho quienes y quales fueron mis padres, y confuſo na-
cimiento, que en ſu tanto, ſi dellos huuiera de eſcreuir-
ſe, fuera ſin duda mas agradable y bien recebida que eſta

3. Identification of words and characters
Impact ground truth identifies regions (paragraphs).
Lines can be usually identified with geometric methods.
The identification of the words and characters is not
straightforward due to the variable separation between
them.
Character breaking, overlapping and kerning are frequent.

4. Gap analysis is not sufficient
Bars mark the position of vertical gaps.

5. Objectives
Apply standard geometric methods to separate (and
deskew) the lines in the image.
Use probabilistic models to identify the best segmentation
of the characters in every line.
Enrich the Impact ground truth with the additional
information (map between characters and images).
Publish source code in the Impact Centre Github.

6. Character features
Candidate features: weight, shadow, gauge, profile,. . .

7. Methodology
Explore what character features are best for alignment.
Employ simple training methods which (in contrast to
HMM) require short training times.
Font size and type (bold, slanted, etc) are not declared in
the ground truth files and they must be therefore
addressed in a second phase of this project.

8. Applications
Training OCR engines, such as Tesseract, with large
samples of characters can be automatized.
Adaptation of OCR engines to a particular book or
collection could be feasible with the manual transcription
of only a few pages.

9. Note: Work on TEI P5
The Miguel de Cervantes library has created about 10,000
books with TEI2 markup.
TEI P5 has associated stylesheets, for example, to create
e-books automatically. However, some limitations were found
to migrate to TEI P5:
Little support for indentation (normal/hanging).
Automatic numeration of verse lines.
No style-support for nested annotation.
Headings cannot be marked for inclusion/exclusion in the
(automatically generated) table of contents.
This experience can be an opportunity for cooperation between
the Centre and the TEI consortium.