| 1. |
- Alonso-Fernandez, Fernando, 1978-, et al.
(författare)
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Combining multiple matchers for fingerprint verification : A case study in biosecure network of excellence
- 2007
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Ingår i: Annales des télécommunications. - Paris, France : Springer. - 0003-4347 .- 1958-9395. ; 62:1-2, s. 62-82
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Tidskriftsartikel (refereegranskat)abstract
- We report on experiments for the fingerprint modality conducted during the First BioSecure Residential Workshop. Two reference systems for fingerprint verification have been tested together with two additional non-reference systems. These systems follow different approaches of fingerprint processing and are discussed in detail. Fusion experiments involving different combinations of the available systems are presented. The experimental results show that the best recognition strategy involves both minutiae-based and correlation-based measurements. Regarding the fusion experiments, the best relative improvement is obtained when fusing systems that are based on heterogeneous strategies for feature extraction and/or matching. The best combinations of two/three/four systems always include the best individual systems whereas the best verification performance is obtained when combining all the available systems.
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| 2. |
- Alonso-Fernandez, Fernando, 1978-, et al.
(författare)
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Fingerprint Recognition
- 2009
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Ingår i: Guide to Biometric Reference Systems and Performance Evaluation. - London : Springer London. - 9781848002913 - 9781848002920 ; , s. 51-88
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- First, an overview of the state of the art in fingerprint recognition is presented, including current issues and challenges. Fingerprint databases and evaluation campaigns, are also summarized. This is followed by the description of the BioSecure Benchmarking Framework for Fingerprints, using the NIST Fingerpint Image Software (NFIS2), the publicly available MCYT-100 database, and two evaluation protocols. Two research systems are compared within the proposed framework. The evaluated systems follow different approaches for fingerprint processing and are discussed in detail. Fusion experiments involving different combinations of the presented systems are also given. The NFIS2 software is also used to obtain the fingerprint scores for the multimodal experiments conducted within the BioSecure Multimodal Evaluation Campaign(BMEC’2007) reported in Chap.11.
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| 3. |
- Assabie, Yaregal, 1975-, et al.
(författare)
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A comprehensive Dataset for Ethiopic Handwriting Recognition
- 2009
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Ingår i: Proceedings SSBA '09. - Halmstad : Halmstad University. - 9789163339240 ; , s. 41-43
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Ethiopic script is used by several languages in Ethiopia for writing. We present a comprehensive dataset of handwritten Ethiopic script called DEHR (Dataset for Ethiopic Handwriting Recognition) captured both offline and online. The offline dataset includes isolated characters, Ethiopian church documents and ordinary handwritten texts dealing with various real-life issues. The ordinary texts and isolated characters were freely written by several participants. The church documents are written in Geez and Amharic languages whereas the language for ordinary texts is Amharic only. The online dataset was collected by using two Digimemo devices of different sizes. For isolated characters and online dataset, all the 265 character samples used by Amharic language are included. The dataset is intended to set a benchmark for training and/or testing handwriting recognition, character and word segmentation, and text line detection. The dataset is can be accessed by contacting the authors or via http://www.hh.se/staff/josef/.
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| 4. |
- Assabie, Yaregal, 1975-, et al.
(författare)
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Ethiopic Character Recognition Using Direction Field Tensor
- 2006
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Ingår i: The 18th International Conference on Pattern Recognition. - Los Alamitos, Calif. : IEEE Computer Society. - 0769525210 ; , s. 284-287
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Konferensbidrag (refereegranskat)abstract
- Many languages in Ethiopia use a unique alphabet called Ethiopic for writing. However, there is no OCR system developed to date. In an effort to develop automatic recognition of Ethiopic script, a novel system is designed by applying structural and syntactic techniques. The recognition system is developed by extracting primitive structural features and their spatial relationships. A special tree structure is used to represent the spatial relationship of primitive structures. For each character, a unique string pattern is generated from the tree and recognition is achieved by matching the string against a stored knowledge base of the alphabet. To implement the recognition system, we use direction field tensor as a tool for character segmentation, and extraction of structural features and their spatial relationships. Experimental results are reported.
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| 5. |
- Assabie, Yaregal, 1975-, et al.
(författare)
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Ethiopic Document Image Database for Testing Character Recognition Systems
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we describe the acquisition and content of a large database of Ethiopic documents for testing and evaluating character recognition systems. The Ethiopic Document Image Database (EDIDB) contains documents written in Amharic and Geez languages. The database was built from a variety of documents such as printouts, books, newspapers, and magazines. Documents written in various font types, sizes and styles were included in the database. Degraded and poor quality documents were also included in the database to represent the real life situation. A total of 1,204 pages were scanned at a resolution of 300 dpi and saved as grayscale images of JPEG format. We also describe an evaluation protocol for standardizing the comparison of recognition systems and their results. The database is made available to the research community through http://www.hh.se/staff/josef/.
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| 6. |
- Assabie, Yaregal, 1975-, et al.
(författare)
-
HMM-Based Handwritten Amharic Word Recognition with Feature Concatenation
- 2009
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Ingår i: Proceedings of the International Conference on Document Analysis and Recognition, ICDAR. - New York : IEEE Press. ; , s. 961-965
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Konferensbidrag (refereegranskat)abstract
- Amharic is the official language of Ethiopia and uses Ethiopic script for writing. In this paper, we present writer-independent HMM-based Amharic word recognition for offline handwritten text. The underlying units of the recognition system are a set of primitive strokes whose combinations form handwritten Ethiopic characters. For each character, possibly occurring sequences of primitive strokes and their spatial relationships, collectively termed as primitive structural features, are stored as feature list. Hidden Markov models for Amharic words are trained with such sequences of structural features of characters constituting words. The recognition phase does not require segmentation of characters but only requires text line detection and extraction of structural features in each text line. Text lines and primitive structural features are extracted by making use of direction field tensor. The performance of the recognition system is tested by a database of unconstrained handwritten documents collected from various sources.
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| 7. |
- Assabie, Yaregal, 1975-, et al.
(författare)
-
Lexicon-based Offline Recognition of Amharic Words in Unconstrained Handwritten Text
- 2008
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Ingår i: 19th International Conference on Pattern Recognition. - New York : IEEE Computer Society. - 9781424421749
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Konferensbidrag (refereegranskat)abstract
- This paper describes an offline handwriting recognition system for Amharic words based on lexicon. The system computes direction fields of scanned handwritten documents, from which pseudo-characters are segmented. The pseudo-characters are organized based on their proximity and direction to form text lines. Words are then segmented by analyzing the relative gap between subsequent pseudocharacters in text lines. For each segmented word image, the structural characteristics of pseudo-characters are syntactically analyzed to predict a set of plausible characters forming the word. The most likelihood word is finally selected among candidates by matching against the lexicon. The system is tested by a database of unconstrained handwritten Amharic documents collected from various sources. The lexicon is prepared from words appearing in the collected database.
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| 8. |
- Assabie, Yaregal, 1975-, et al.
(författare)
-
Multifont size-resilient recognition system for Ethiopic script
- 2007
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Ingår i: International Journal on Document Analysis and Recognition. - Berlin : Springer Berlin/Heidelberg. - 1433-2833 .- 1433-2825. ; 10:2, s. 85-100
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a novel framework for recognition of Ethiopic characters using structural and syntactic techniques. Graphically complex characters are represented by the spatial relationships of less complex primitives which form a unique set of patterns for each character. The spatial relationship is represented by a special tree structure which is also used to generate string patterns of primitives. Recognition is then achieved by matching the generated string pattern against each pattern in the alphabet knowledge-base built for this purpose. The recognition system tolerates variations on the parameters of characters like font type, size and style. Direction field tensor is used as a tool to extract structural features.
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| 9. |
- Assabie, Yaregal, 1975-, et al.
(författare)
-
Offline Handwritten Amharic Word Recognition Using HMMs
- 2009
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Ingår i: Proceedings SSBA '09. - Halmstad : Halmstad University. - 9789163339240 ; , s. 89-92
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This paper describes two appraches for Amharic word recognition in unconstrained handwritten text using HMMs. The first approach builds word models from concatenated features of constituent characters and in the second method HMMs of constituent characters are concatenated to form word model. In both cases, the features used for training and recognition are primitive strokes and their spatial relationships. The recognition system does not require segmentation of characters but requires text line detection and extraction of structural features, which is done by making use of direction field tensor. The performance of the recognition system is tested by DEHR dataset of unconstrained handwritten documents collected from various sources.
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| 10. |
- Assabie, Yaregal, 1975-, et al.
(författare)
-
Online Handwriting Recognition of Ethiopic Script
- 2008
-
Ingår i: Proceedings. - Montréal : CENPARMI, Concordia University. - 1895193036 - 9781895193039 ; , s. 153-158
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Konferensbidrag (refereegranskat)abstract
- Online recognition of handwritten characters is gaining a renewed interest as it provides a natural way of data entry for a wide variety of handheld devices. In this paper, we present online handwriting recognition system for Ethiopic script based on the structural and syntactical analysis of the strokes forming characters. The complex structures of characters are represented by the spatio- temporal relationships of simple-shaped strokes called primitives. A special tree structure is used to model spatio- temporal relationships of the strokes. The tree generates a unique set of primitive stroke sequences for each character, and for recognition each stroke sequence is matched against a stored knowledge base. Characters are also classified based on their structural similarity to select a plausible set of characters for un unknown input, which improves recognition and processing time. We also present a dataset collected for training and testing online recognition systems for Ethiopic script. The dataset is prepared in accordance with the international standard UNIPEN format. The recognition system is tested with the collected dataset and experimental results are reported.
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