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Juan Ignacio Toledo, Sounak Dey, Alicia Fornes and Josep Llados. 2017. Handwriting Recognition by Attribute embedding and Recurrent Neural Networks. 14th International Conference on Document Analysis and Recognition.1038–1043.
Abstract: Handwriting recognition consists in obtaining the transcription of a text image. Recent word spotting methods based on attribute embedding have shown good performance when recognizing words. However, they are holistic methods in the sense that they recognize the word as a whole (i.e. they find the closest word in the lexicon to the word image). Consequently,
these kinds of approaches are not able to deal with out of vocabulary words, which are common in historical manuscripts. Also, they cannot be extended to recognize text lines. In order to address these issues, in this paper we propose a handwriting recognition method that adapts the attribute embedding to sequence learning. Concretely, the method learns the attribute embedding of patches of word images with a convolutional neural network. Then, these embeddings are presented as a sequence to a recurrent neural network that produces the transcription. We obtain promising results even without the use of any kind of dictionary or language model
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Juan Ignacio Toledo, Sebastian Sudholt, Alicia Fornes, Jordi Cucurull, A. Fink and Josep Llados. 2016. Handwritten Word Image Categorization with Convolutional Neural Networks and Spatial Pyramid Pooling. Joint IAPR International Workshops on Statistical Techniques in Pattern Recognition (SPR) and Structural and Syntactic Pattern Recognition (SSPR). Springer International Publishing, 543–552. (LNCS.)
Abstract: The extraction of relevant information from historical document collections is one of the key steps in order to make these documents available for access and searches. The usual approach combines transcription and grammars in order to extract semantically meaningful entities. In this paper, we describe a new method to obtain word categories directly from non-preprocessed handwritten word images. The method can be used to directly extract information, being an alternative to the transcription. Thus it can be used as a first step in any kind of syntactical analysis. The approach is based on Convolutional Neural Networks with a Spatial Pyramid Pooling layer to deal with the different shapes of the input images. We performed the experiments on a historical marriage record dataset, obtaining promising results.
Keywords: Document image analysis; Word image categorization; Convolutional neural networks; Named entity detection
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Juan Ignacio Toledo, Manuel Carbonell, Alicia Fornes and Josep Llados. 2019. Information Extraction from Historical Handwritten Document Images with a Context-aware Neural Model. PR, 86, 27–36.
Abstract: Many historical manuscripts that hold trustworthy memories of the past societies contain information organized in a structured layout (e.g. census, birth or marriage records). The precious information stored in these documents cannot be effectively used nor accessed without costly annotation efforts. The transcription driven by the semantic categories of words is crucial for the subsequent access. In this paper we describe an approach to extract information from structured historical handwritten text images and build a knowledge representation for the extraction of meaning out of historical data. The method extracts information, such as named entities, without the need of an intermediate transcription step, thanks to the incorporation of context information through language models. Our system has two variants, the first one is based on bigrams, whereas the second one is based on recurrent neural networks. Concretely, our second architecture integrates a Convolutional Neural Network to model visual information from word images together with a Bidirecitonal Long Short Term Memory network to model the relation among the words. This integrated sequential approach is able to extract more information than just the semantic category (e.g. a semantic category can be associated to a person in a record). Our system is generic, it deals with out-of-vocabulary words by design, and it can be applied to structured handwritten texts from different domains. The method has been validated with the ICDAR IEHHR competition protocol, outperforming the existing approaches.
Keywords: Document image analysis; Handwritten documents; Named entity recognition; Deep neural networks
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Juan Ignacio Toledo, Jordi Cucurull, Jordi Puiggali, Alicia Fornes and Josep Llados. 2015. Document Analysis Techniques for Automatic Electoral Document Processing: A Survey. E-Voting and Identity, Proceedings of 5th international conference, VoteID 2015.139–141. (LNCS.)
Abstract: In this paper, we will discuss the most common challenges in electoral document processing and study the different solutions from the document analysis community that can be applied in each case. We will cover Optical Mark Recognition techniques to detect voter selections in the Australian Ballot, handwritten number recognition for preferential elections and handwriting recognition for write-in areas. We will also propose some particular adjustments that can be made to those general techniques in the specific context of electoral documents.
Keywords: Document image analysis; Computer vision; Paper ballots; Paper based elections; Optical scan; Tally
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Juan Ignacio Toledo, Alicia Fornes, Jordi Cucurull and Josep Llados. 2016. Election Tally Sheets Processing System. 12th IAPR Workshop on Document Analysis Systems.364–368.
Abstract: In paper based elections, manual tallies at polling station level produce myriads of documents. These documents share a common form-like structure and a reduced vocabulary worldwide. On the other hand, each tally sheet is filled by a different writer and on different countries, different scripts are used. We present a complete document analysis system for electoral tally sheet processing combining state of the art techniques with a new handwriting recognition subprocess based on unsupervised feature discovery with Variational Autoencoders and sequence classification with BLSTM neural networks. The whole system is designed to be script independent and allows a fast and reliable results consolidation process with reduced operational cost.
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Juan Ignacio Toledo. 2019. Information Extraction from Heterogeneous Handwritten Documents. (Ph.D. thesis, Ediciones Graficas Rey.)
Abstract: In this thesis we explore information Extraction from totally or partially handwritten documents. Basically we are dealing with two different application scenarios. The first scenario are modern highly structured documents like forms. In this kind of documents, the semantic information is encoded in different fields with a pre-defined location in the document, therefore, information extraction becomes roughly equivalent to transcription. The second application scenario are loosely structured totally handwritten documents, besides transcribing them, we need to assign a semantic label, from a set of known values to the handwritten words.
In both scenarios, transcription is an important part of the information extraction. For that reason in this thesis we present two methods based on Neural Networks, to transcribe handwritten text.In order to tackle the challenge of loosely structured documents, we have produced a benchmark, consisting of a dataset, a defined set of tasks and a metric, that was presented to the community as an international competition. Also, we propose different models based on Convolutional and Recurrent neural networks that are able to transcribe and assign different semantic labels to each handwritten words, that is, able to perform Information Extraction.
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Josep Llados, Horst Bunke and Enric Marti. 1997. Using Cyclic String Matching to Find Rotational and Reflectional Symmetries in Shapes. Intelligent Robots: Sensing, Modeling and Planning. World Scientific Press, 164–179.
Abstract: Dagstuhl Workshop
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Josep Llados and Young-Bin Kwon. 2004. Graphics Recognition. Recent Advances and Perspectives.
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Josep Llados, W. Liu and Jean-Marc Ogier. 2007. Seventh IAPR International Workshop on Graphics Recognition GREC 2007.
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Josep Llados, Partha Pratim Roy, Jose Antonio Rodriguez and Gemma Sanchez. 2007. Word Spotting in Archive Documents using Shape Contexts. 3rd Iberian Conference on Pattern Recognition and Image Analysis (IbPRIA 2007), J. Marti et al. (Eds.) LNCS 4478:290–297.
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