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9. A Robust Braille Recognition System

Author

Antonacopoulos, Apostolos, Bridson, David, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Marinai, Simone, editor, and Dengel, Andreas R., editor

Published
2004
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10. A Complete Approach to the Conversion of Typewritten Historical Documents for Digital Archives

Author

Antonacopoulos, Apostolos, Karatzas, Dimosthenis, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Marinai, Simone, editor, and Dengel, Andreas R., editor

Published
2004
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11. A survey of OCR evaluation tools and metrics

Author

Clausner Christian, Clemens Neudecker, Antonacopoulos Apostolos, Mike Gerber, Pletschacher Stefan, and Konstantin Baierer

Subjects
Ground truth, Information retrieval, Keyword search, Computer science, media_common.quotation_subject, Optical character recognition, computer.software_genre, Reading (process), ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Quality (business), Use case, computer, Digitization, media_common
Abstract

The millions of pages of historical documents that are digitized in libraries are increasingly used in contexts that have more specific requirements for OCR quality than keyword search. How to comprehensively, efficiently and reliably assess the quality of OCR results against the background of mass digitization, when ground truth can only ever be produced for very small numbers? Due to gaps in specifications, results from OCR evaluation tools can return different results, and due to differences in implementation, even commonly used error rates are often not directly comparable. OCR evaluation metrics and sampling methods are also not sufficient where they do not take into account the accuracy of layout analysis, since for advanced use cases like Natural Language Processing or the Digital Humanities, accurate layout analysis and detection of the reading order are crucial. We provide an overview of OCR evaluation metrics and tools, describe two advanced use cases for OCR results, and perform an OCR evaluation experiment with multiple evaluation tools and different metrics for two distinct datasets. We analyze the differences and commonalities in light of the presented use cases and suggest areas for future work.

Published
2021

13. A New Deep Wavefront Based Model for Text Localization in 3D Video.

Author

Nandanwar, Lokesh, Shivakumara, Palaiahnakote, Ramachandra, Raghavendra, Lu, Tong, Pal, Umapada, Antonacopoulos, Apostolos, and Lu, Yue

Subjects
LOCALIZATION (Mathematics), ELECTRONIC equipment, VIDEO processing, VIDEOS
Abstract

With the evolution of electronic devices, such as 3D cameras, addressing the challenges of text localization in 3D video (e.g., for indexing) is increasingly drawing the attention of the multimedia and video processing community. Existing methods focus on 2D video and their performance in the presence of the challenges in 3D video, such as shadow areas associated with text and irregularly sized and shaped text, degrades. This paper proposes the first approach that successfully addresses the challenges of 3D video in addition to those of 2D. It employs a number of innovations, among which, the first is the Generalized Gradient Vector Flow (GGVF) for dominant points detection. The second is the Wavefront concept for text candidate point detection from those dominant points. In addition, an Adaptive B-Spline Polygon Curve Network (ABS-Net) is proposed for accurate text localization in 3D videos by constructing tight fitting bounding polygons using text candidate points. Extensive experiments on custom (3D video) and standard datasets (2D video and scene text) show that the proposed method is practical and useful, and overall outperforms existing state-of-the-art methods. [ABSTRACT FROM AUTHOR]

Published
2022
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17. VISE

Author

Usman, Mahmud Ahmed, primary and Antonacopoulos, Apostolos, additional

Published
2019
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30. Highlights of the novel dewaterability estimation test (DET) device.

Author

Scholz, Miklas, Almuktar, Suhad, Clausner, Christian, and Antonacopoulos, Apostolos

Subjects
IMAGE analysis software, COMPUTER equipment, STANDARD deviations, TESTING
Abstract

Many industries, which are producing sludge in large quantities, depend on sludge dewatering technology to reduce the corresponding water content. A key design parameter for dewatering equipment is the capillary suction time (CST) test, which has, however, several scientific flaws, despite that the test is practical and easy-to-perform. The standard CST test has a few considerable drawbacks: its lack of reliability and difficulties in obtaining results for heavy sludge types. Furthermore, it is not designed for long experiments (e.g. >30 min), and has only two measurement points (its two electrodes). In comparison, the novel dewaterability estimation test (DET) test is almost as simple as the CST, but considerably more reliable, faster, flexible and informative in terms of the wealth of visual measurement data collected with modern image analysis software. The standard deviations associated with repeated measurements for the same sludge is lower for the DET than for the CST test. In contrast to the CST device, capillary suction in the DET test is linear and not radial, allowing for a straightforward interpretation of findings. The new DET device may replace the CST test in the sludge-producing industries in the future. [ABSTRACT FROM AUTHOR]

Published
2020
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33. BACK MATTER

Author

Märgner, Volker, primary, Pal, Umapada, additional, and Antonacopoulos, Apostolos, additional

Published
2018
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34. FRONT MATTER

Author

Märgner, Volker, primary, Pal, Umapada, additional, and Antonacopoulos, Apostolos, additional

Published
2018
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41. Unearthing the Recent Past

Author

Clausner, Christian, primary, Hayes, Justin, additional, Antonacopoulos, Apostolos, additional, and Pletschacher, Stefan, additional

Published
2017
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49. A FUZZY APPROACH TO TEXT SEGMENTATION IN WEB IMAGES BASED ON HUMAN COLOUR PERCEPTION

Author

Antonacopoulos, Apostolos, Karatzas, Dimosthenis, Antonacopoulos, Apostolos, and Hu, J

Abstract

This chapter describes a new approach for the segmentation of text in images on Web pages. In the same spirit as the authors’ previous work on this subject, this approach attempts to model the ability of humans to differentiate between colours. In this case, pixels of similar colour are first grouped using a colour distance defined in a perceptually uniform colour space (as opposed to the commonly used RGB). The resulting colour connected components are then grouped to form larger (character-like) regions with the aid of a propinquity measure, which is the output of a fuzzy inference system. This measure expresses the likelihood for merging two components based on two features. The first feature is the colour distance between the components, in the L*a*b* colour space. The second feature expresses the topological relationship of two components. The results of the method indicate a better performance than previous methods devised by the authors and possibly better (a direct comparison is not really possible due to the differences in application domain characteristics between this and previous methods) performance to other existing methods.

Published
2003

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