1	Textual images Module 4 Min-Yen KAN *Portions of this lecture based on Managing Gigabytes textbook
2	Cost basis for archives
3	Digitization Scanning Binding Planetary scanner Resolution of scan 300 dpi for access 600 or higher for archival copy
4	Digitization Purpose: ________ Quality Stability in the long term _______ Delivery Editing Annotation Initiate the digitalization project Establish start-up costs and secure funding Prepare a detailed project plan include milestones and deliverables Assess and select materials for digitization Digitize materials (prepare source materials, digitize, check quality) Post-process digital materials: edit, OCR, store, catalog and index Deliver and make materials accessible Support and maintenance of materials -- From Chowdhury and Chowdhury (03)
5	Document capture costs in USD
6	Images of text You’ve scanned in an image like this… What to do with it? How would we like to store and access this information?
7	Storing a textual image Mostly bi-level (two-tone) CCITT Fax III and IV Bi-level transmission and storage standard Optimized for Roman alphabet Textual image compression Codebook of marks A level for access and one for preservation
8	CCITT Fax IV
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10	CCITT fax group IV
11	Textual image compression Find and isolate marks (connected group of black pixels) Construct library of symbols Identify the symbol closes to each mark and get coordinates Store information *Store additional information to reconstruct original image
12	Text image outline Storage √ CCITT Fax Group III and IV √ Textual image compression √ Access De-skew Segmentation Media detection
13	De-Skew Projection profile Accumulate Y-axis pixel histogram Rotate to find most crisp histogram One of three common algorithms
14	Segmentation Top-down (e.g., _______) Bottom-up (e.g. _________)
15	Classification Separate: Images Text Line art Equations Tables One technique: Slope Histogram (Hough transform)