[Music]
In June 2022, the Transcription Project of the Diario de
Madrid already had more than 200 pages processed manually,
a volume enough to start training a model
for the recognition of manuscript text.
Let's remember the beginnings of the project.
To begin with, a model was used designed
for theatrical texts of the Golden Century,
but the newspapers of the Diario de Madrid have other characteristics,
many more numbers, abbreviations and a more administrative style.
That's why it was necessary to adjust the model for this new domain.
The goal? Reduce the error by character below 1%.
What language models like those used by Transcribus do
is learn how words are distributed in texts.
But how?
Well, by looking at lots of texts, analyzing patterns and repetitions.
Transcribus, for example, starts with a
model that has already read a huge corpus
and then adjusts it with the specific texts that
you give it to train it according to your needs.
Once the model is trained with that corpus,
it is time to check how it performs.
And that is done by applying it to a set of
different texts called the validation set.
There we measure if the model is recognizing
well or if it is making a mistake.
Of course, to detect errors, we need to be
clear about what the correct result would be,
that is, what is the transcription we expect.
Only then can we know if the model has done it well or not so well.
Several key parameters were evaluated in
training, such as the number of times,
that is, how many times the model sees
each page of the newspaper during training,
or the composition of the training and validation sets.
With only 4 times, the model was already
able to recognize many characters,
especially numbers that used to fail.
The CER in training was excellent, 0.
34%, but in validation it Rose to 3.
93%, so there was still work to be done.
In this way, the number of documents was progressively increased
and the training was expanded with subsequent tests.
The improvement continued until test 13.
There, with 300 times and 176 pages, the
goal of a CER close to 1 was achieved.
At that point, some inconsistencies in the transcriptions were detected
due to differences between the annotators.
This led to reviewing and homogenizing the corpus,
which also helped to stabilize the results.
And now comes the interesting part.
During the process, Transcribus incorporated a new IA model, Pyl-IA.
This recognition system offers two great advantages.
On the one hand, it allows you to directly
adjust the parameters of the model
and, on the other, it no longer requires
that the layout is segmented in advance.
Of course, a manual review is still
necessary to correct residual errors.
With all this, in January 2023, the model
was published on the Transcribus platform
under the name "Diario de Madrid 1788-1825".
Later, it was integrated into an even more ambitious model,
the Spanish Colossus, coordinated by Dr. Álvaro Cuellar.
And finally, we rescue a good example of the scope of this technology,
the ability to more accurately attribute
the authorship of historical texts,
as in the case of "La Francesa Laura",
today recognized as a work by Lope de Vega.
Transcribed by ESO; Translated by —.