Jose Antonio Rodriguez, & Florent Perronnin. (2009). Handwritten word-spotting using hidden Markov models and universal vocabularies. PR - Pattern Recognition, 42(9), 2103–2116.
Abstract: Handwritten word-spotting is traditionally viewed as an image matching task between one or multiple query word-images and a set of candidate word-images in a database. This is a typical instance of the query-by-example paradigm. In this article, we introduce a statistical framework for the word-spotting problem which employs hidden Markov models (HMMs) to model keywords and a Gaussian mixture model (GMM) for score normalization. We explore the use of two types of HMMs for the word modeling part: continuous HMMs (C-HMMs) and semi-continuous HMMs (SC-HMMs), i.e. HMMs with a shared set of Gaussians. We show on a challenging multi-writer corpus that the proposed statistical framework is always superior to a traditional matching system which uses dynamic time warping (DTW) for word-image distance computation. A very important finding is that the SC-HMM is superior when labeled training data is scarce—as low as one sample per keyword—thanks to the prior information which can be incorporated in the shared set of Gaussians.
Keywords: Word-spotting; Hidden Markov model; Score normalization; Universal vocabulary; Handwriting recognition
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Alfons Juan-Ciscar, & Gemma Sanchez. (2008). PRIS 2008. Pattern Recognition in Information Systems. Proceedings of the 8th international Workshop on Pattern Recognition in Information systems – PRIS 2008, in conjunction with ICEIS 2008.
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Xavier Otazu, Maria Vanrell, & C. Alejandro Parraga. (2008). Colour induction effects are modelled by a low-level multiresolution wavelet framework. Perception 37(Suppl.): 107.
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Hugo Berti, Angel Sappa, & Osvaldo Agamennoni. (2008). Improved Dynamic Window Approach by Using Lyapunov Stability Criteria. Latin American Applied Research, 289–298.
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Fadi Dornaika, & Angel Sappa. (2008). Real Time Image Registration for Planar Structure and 3D Sensor Pose Estimation. In Asim Bhatti (Ed.), Stereo Vision (Vol. 18, 299–316).
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Jaume Garcia, Debora Gil, Sandra Pujades, & Francesc Carreras. (2008). A Variational Framework for Assessment of the Left Ventricle Motion. International Journal Mathematical Modelling of Natural Phenomena, 3(6), 76–100.
Abstract: Impairment of left ventricular contractility due to cardiovascular diseases is reflected in left ventricle (LV) motion patterns. An abnormal change of torsion or long axis shortening LV values can help with the diagnosis and follow-up of LV dysfunction. Tagged Magnetic Resonance (TMR) is a widely spread medical imaging modality that allows estimation of the myocardial tissue local deformation. In this work, we introduce a novel variational framework for extracting the left ventricle dynamics from TMR sequences. A bi-dimensional representation space of TMR images given by Gabor filter banks is defined. Tracking of the phases of the Gabor response is combined using a variational framework which regularizes the deformation field just at areas where the Gabor amplitude drops, while restoring the underlying motion otherwise. The clinical applicability of the proposed method is illustrated by extracting normality models of the ventricular torsion from 19 healthy subjects.
Keywords: Key words: Left Ventricle Dynamics, Ventricular Torsion, Tagged Magnetic Resonance, Motion Tracking, Variational Framework, Gabor Transform.
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Marçal Rusiñol, & Josep Llados. (2008). Word and Symbol Spotting using Spatial Organization of Local Descriptors. In Proceedings of the 8th IAPR International Workshop on Document Analysis Systems, (489–496).
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Mathieu Nicolas Delalandre, Ernest Valveny, & Josep Llados. (2008). Performance Evaluation of Symbol Recognition and Spotting Systems. In Proceedings of the 8th International Workshop on Document Analysis Systems, (497–505).
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Joan Mas, Jose Antonio Rodriguez, Dimosthenis Karatzas, Gemma Sanchez, & Josep Llados. (2008). HistoSketch: A Semi-Automatic Annotation Tool for Archival Documents. In Proceedings of the 8th International Workshop on Document Analysis Systems, (517–524).
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Dimosthenis Karatzas. (2008). Detecting Gradients in Text Images Using the Hough Transform. In Proceedings of the 8th International Workshop on Document Analysis Systems, (245–252).
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Ernest Valveny, & Miquel Ferrer. (2008). Application of Graph Embedding to Solve Graph Matchin Problems. In Colloque International Francophone sur l’Ecrit et le Document (13–18).
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Miquel Ferrer, Ernest Valveny, F. Serratosa, K. Riesen, & Horst Bunke. (2008). An Approximate Algorith for Median Graph Computation using Graph Embedding. In 19th International Conference on Pattern Recognition..
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Dimosthenis Karatzas, Marçal Rusiñol, Coen Antens, & Miquel Ferrer. (2008). Segmentation Robust to the Vignette Effect for Machine Vision Systems. In 19th International Conference on Pattern Recognition.
Abstract: The vignette effect (radial fall-off) is commonly encountered in images obtained through certain image acquisition setups and can seriously hinder automatic analysis processes. In this paper we present a fast and efficient method for dealing with vignetting in the context of object segmentation in an existing industrial inspection setup. The vignette effect is modelled here as a circular, non-linear gradient. The method estimates the gradient parameters and employs them to perform segmentation. Segmentation results on a variety of images indicate that the presented method is able to successfully tackle the vignette effect.
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Jose Antonio Rodriguez, & Florent Perronnin. (2008). Local Gradient Histogram Features for Word Spotting in Unconstrained Handwritten Documents. In International Conference on Frontiers in Handwriting Recognition (7–12).
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Jose Antonio Rodriguez, & Florent Perronnin. (2008). Score Normalization for Hmm-based Word Spotting Using Universal Background Model. In International Conference on Frontiers in Handwriting Recognition (82–87).
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