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Stefan Pletschacher; Marcel Eckert; Arved C. Hübler

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Presentation on theme: "Stefan Pletschacher; Marcel Eckert; Arved C. Hübler"— Presentation transcript:

1 Stefan Pletschacher; Marcel Eckert; Arved C. Hübler
Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing Stefan Pletschacher; Marcel Eckert; Arved C. Hübler

2 Digitization of Historical Documents
GEB1150 Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

3 Alphabet und Font Extraction
Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

4 Vectorization - Raster to Vector Conversion
41 hex encoded text e.g. ASCII font assignment OCR RIP bitmap graphic vector font Vectorization Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

5 DIA System und Workflow
Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

6 DIA System und Workflow
Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

7 DIA System und Workflow
XML Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

8 Vectorization Approaches
Contour based Skeleton based Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

9 Applied Algorithms Pre-processing
- Finding connected components (Region Growing) - Contour extraction (Contour following) Polygonal Approximation Based on Relaxation - Phase 1: Clustering of polygonal points - Phase 2: Relaxation (Error correction) Automatic Parameter Control - Rasterization of the resulting glyph images - Ascertaining a weighted error (Ground Truth) - Selecting appropriate vectorization parameters Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

10 Finding Connected Components
Ü Ö Ä % “ ! Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

11 Region Growing Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

12 Contour Following white pixel black pixel starting point
examination order Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

13 Clustering of Polygonal Points
Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

14 Relaxation Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

15 SVG Representation Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

16 Visual Quality Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

17 Formal Quality Measurement - Ground Truth
Error function - absolute number of wrong pixels - weighted by the distance to the next true component Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

18 Results Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

19 Adaptive Parameter Control
Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

20 Compression rates Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

21 Conclusions Good vectorization results already with linear primitives
High compression rates can be achieved Extracted fonts can be easily scaled and further formatted Known vectorization methods have been extended towards an adaptive system for automatic parameter control These methods can be applied for preservation and handling of unknown type faces in digitized documents Originals may be re-encoded using a document specific alphabet and font Direct integration into XML/SVG based processes possible Various output formats can be supported by means of XSL transformations Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006

22 Thank you very much! Questions stefan.pletschacher@mb.tu-chemnitz.de
Pletschacher • Vectorization of Glyphs and Their Representation in SVG for XML‑based Processing • ELPUB 2006


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