Document Image Analysis CSE 717 An Introduction

Document Image Analysis

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DIA is the theory and practice of recovering the symbol structures of digital images scanned from paper or produced by computer DIA is a subfield of Digital Image processing

  Digital images of natural objects: X-rays, fingerprints, faces, scenery, etc. are NOT part of DIA Digital images of symbolic objects: Postal addresses, printed articles, forms, music sheets, engineering drawings, topographic maps belong to DIA   Source: Scanners, printers, fax machines, hand!

Incidental text: license plates, billboards, subtitles, in photos and video  WWW ??

DIA’s grand goal is take us to the land of paperless office

Document Image Analysis Textual Processing Graphical Processing Optical Character Recognition Text Page Layout Analysis Line Processing Region and Symbol Processing Skew, blocks, paragraphs Lines, curves, corners Filled regions

Processing Pixels Primitives Structures Documents Corpus

Document Image Analysis

Text Preprocessing

Representation, Noise removal, binarization, skew, script id, font id

Graphics Preprocessing

Representation, Noise removal, binarization, thinning, vectorization

Glyph Recognition

Connected components, strokes, punctuations, words

Text Recognition

Word segmentation, text line reconstruction, table analysis, linguistics

Primitive Recognition

Straight lines, curve segments, junctions, nodes, loops, characters

Structure Recognition

Text fields, legends, labels, dimensions, graphics symbols

Page Layout Analysis

Text versus non-text, physical component analysis, logical component analysis, functional component analysis, compression

Interpretation

Component recognition, connectivity analysis, CAD layer separation, Database attribute extraction, Compression

Information Retrieval

Document Classification, indexing, search, security, authentication, privacy

Database, CAD

Validation, search, update

Sender’s Address Linear Code Endorsem

In Case of Undeliverable as Addressed Return to Sender

ent Delivery Address

Postal Examples

Meter Mark Digital Post Mark

Forms

Unconstrained Text

Graphics Documents

References

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Handbook of Character Recognition and Document Image Analysis, H. Bunke and PSP Wang (editors), World Scientific Press Document Image Analysis, Gorman and Kasturi , IEEE Computer Society Press International Conference on Document Analysis and Recognition proceedings International Workshop on Document Analysis Systems proceedings Symposium on Document Image Understanding Technology

•OCR Features and Systems –Script ID, Devanagari OCR, Tamil OCR, MP versus HW •Handwriting Recognition –Postal applications, Arabic Documents •Classifiers and Learning –Multi-classifier systems •Layout Analysis –Skew correction, geometric methods, test/graphics separation, logical labeling •Tables and Forms –Detecting tables in HTML documents, use of graph grammars, semantics •Document Engineering –Processing of historical documents (palm leaf manuscripts).

•Camera Based DIA –Locating and reading Barcodes •New Applications -CAPTCHA