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PSI 2005 N. Ramangaseheno

Presentation of the Project Environment of Work Introducing the Subject Unformat Process Applied to Graphics Indexing Contributions Applications. Unformating SVG Documents. PSI 2005 N. Ramangaseheno. Environment of Work. Laboratories :

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PSI 2005 N. Ramangaseheno

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  1. Presentation of the Project Environment of Work Introducing the Subject Unformat Process Applied to Graphics Indexing Contributions Applications Unformating SVG Documents PSI 2005 N. Ramangaseheno

  2. Environment of Work • Laboratories : • DI (Document Interaction) team of PSI (Perception, Systèmes, Information) laboratory, University of Rouen, France, • IPI (Image Processing and Interpretation) research group of SCSIT (School of Computer Science and Information Technology), University of Notthingham, England. • Tutors : • Eric Trupin, « Directeur de Recherche » within the PSI, • Tony Pridmore, Senior Lecturer, member of IPIresearch group. • Collaborations : • Mathieu Delalandre, post-doc within the IPI group, • Karim Zouba, master traineewithin the PSI. • Integrated project : Indexation de graphiques vectoriels • Programming language : Java • Trainning period :april 2005 - september 2005

  3. Presentation of the Project Environment of Work Introducing the Subject Unformat Process Applied to Graphics Indexing Contributions Applications Unformating SVG Documents PSI 2005 N. Ramangaseheno

  4. a vector graphic miyamoto.ai a SVG rectangle a WMF pen an EPS plane <rect x="400" y="100" width="400“ height="200" fill="yellow" stroke="navy" stroke-width="10" /> (a) (b) Vector Graphics • Common vector formats : • AI (Adobe Illustrator) • SVG (Scalable Vector Graphic) • WMF (Windows Metafile) • EPS (Encapsulted PostScript) • DXF (AutoCAD) PSI 2005 N. Ramangaseheno

  5. Image Indexing Graphics types : - raster images or bitmaps - vector mages Indexing : automatic extraction of informative characteristics from multimedia containers to aid retrieval and browsing through large databases. Architecture of an image indexing system Graphic document Conception of visual descriptors Image signature Measure of similarity Image database Classification PSI 2005 N. Ramangaseheno

  6. Unformating SVG Documents • Presentation of the Project • Environment of Work • Introducing the Subject • Unformat Process Applied to Graphics Indexing • Contributions • Applications PSI 2005 N. Ramangaseheno

  7. Diagram of the Indexing System Generator of synthetic documents Vector graphic Unformat process Low-level representation Analyzer High-level representation PSI 2005 N. Ramangaseheno

  8. SVG document unformated document R1 R2 R3 Problem with Unformating Why unformat before analysing ? PSI 2005 N. Ramangaseheno

  9. SVG document unformated document R1 R2 R3 region graph Problem with Unformating acquiring modelling filtering PSI 2005 N. Ramangaseheno

  10. Unformating SVG Documents • Presentation of the Project • Contributions • Diagram of the Unformat System • The SVG Format • Parsing • Modelling • Filtering • Intersection Search • Applications PSI 2005 N. Ramangaseheno

  11. SVG document Diagram of the Unformat System parsing filtering intersection search modelling

  12. Unformating SVG Documents • Presentation of the Project • Contributions • Diagram of the Unformat System • The SVG Format • Parsing • Modelling • Filtering • Intersection Search • Applications PSI 2005 N. Ramangaseheno

  13. a SVG rectangle <rect x="400" y="100" width="400“ height="200" fill="yellow" stroke="navy" stroke-width="10" /> (a) (b) The SVG Format Norm and advantages: • W3C norm for describing 2D graphics => open standard • Growing format   => growig number of visualizers and users • Vectorial description of graphical objects => scalablility • Based on XML (described by a DTD); compatible with XLink, XPointer, CSS/XSL, and SMIL (animation language) => textual, separation between semantic and presentation • Scripts and animations started on associated events => interactif Inconvenient : • Lack of realism Adapté pour : • Interactive geographic maps • Technical drawings • XML accounts PSI 2005 N. Ramangaseheno

  14. Structure of a SVG Document Exemple : <?xml version="1.0" encoding="iso-8859-1" standalone="no"?> <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.0//EN" "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd"> <svg width="5cm" height="4cm"> <desc>Un joli rectangle</desc> <rect x="3cm" y="0.5cm" width="1.5cm" height="2cm"/> </svg>

  15. Common shapes Ellipse:<ellipse cx="400" cy="300" rx="72" ry="50" /> Rectangle:<rect x="150" y="50" width="135" height="100" /> Circle:<circle cx="70" cy="100" r="50" /> Line: <line x1="375" y1="50" x2="425" y2="150" /> Polyline:<polyline points="50, 250,75,350,100,250,125,350" /> Polygon:<polygon points="250,250,297,284,279,340,220,340" /> Complex shape Path:<path d="M 50 250 L 100 250 L 150 300"/> Geometrical Shapes

  16. Unformating SVG Documents • Presentation of the Project • Contributions • Diagram of the Unformat System • The SVG Format • Parsing • Modelling • Filtering • Intersection Search • Applications PSI 2005 N. Ramangaseheno

  17. SAX Parser Architecture of a SAX application treated events • Any XML handling need a parser • a parser is a syntaxic analyzer; it is placed between the XML file and the application • a parser can be used : • from a program (script, java, C++) • from a navigator • SAX, event driven parser • handler methods called from special events • file sequentially analyzed before being transmitted to the application Handler startDocument() startElement() endElement() endDocument()

  18. SVG Parsing Parser SAX startDocument() startElement() characters endElement() endDocument() SVGcode SVGdocument graphical objects met events vectorial representation PSI 2005 N. Ramangaseheno

  19. Unformating SVG Documents • Presentation of the Project • Contributions • Diagram of the Unformat System • The SVG Format • Parsing • Modelling • Filtering • Intersection Search • Applications PSI 2005 N. Ramangaseheno

  20. OGraphic OGraphicImpl OHL OExtremity OJunction OPoint OLine linked-squares point list line list line graph hierarchical list hierarchical graph Graphical Objects Modelling GOMLib [Delalandre 2004]: • Graphical Objects Modelling Library • XML and SVG export • Multi-model : different representations possible PSI 2005 N. Ramangaseheno

  21. Unformating SVG Documents • Presentation of the Project • Contributions • Diagram of the Unformat System • The SVG Format • Parsing • Modelling • Filtering • Intersection Search • Applications PSI 2005 N. Ramangaseheno

  22. Filtering superfluous lines visuallly in reality Need filtering to respect orders 1 point of a 2D planimetry = 1 single representation

  23. b2 e2 b1 e1 Preliminary Tests (1/2) • Given - two lines L1 et L2 • - b1(xb1,yb1) begin point of L1 ; b2(xb2,yb2) begin point of L2 • - e2(xe2,ye1) end point of L1 ; e2(xe2,ye2) end point of L2 • L1 isEqual L2 : L1 and L2 are equal if • xb1 =xb2 ; yb1 =yb2 ; xe1 =xe2 ; ye1 =ye2 ; • L1 isParallel L2 : L1 and L2 are parallel if • (( xe1 - xb1 ) * ( xe2 - xb2 )- ( ye1 - yb1 ) * ( ye2 -yb2 )) = 0 • L1 isColinear p : a point p(x,y) is colinear to L1 if • y = t * x + o • (t = ( ye1 - yb1 ) / (xe1 - xb1 ) and o =yb1 - t * xb1 ) • L1 isColinear L2: L2 is colinear to L1 if • L1 isColinear b2 and L1 isColinear e2 PSI 2005 N. Ramangaseheno

  24. Preliminary Tests (2/2) • L1 overlaps p : L1 overlaps a point p(x,y) if • (( x- xb1 ) * ( x - xe1 )) < 0 or (( y- yb1 ) * ( y - ye1 )) < 0 • L1 overlaps L2 : L1 overlaps L2 if • L1 overlaps( b2 ) or L1 overlaps( e2 ) • L1 isConnected p : L1 is connected to the point p(x,y) if • b1 = p • or e1 = p • L1 isConnected L2 : L1 is connected to L2 if • L1 isConnected b2 • or L1 isConnected e2 l1 is connected to l2 PSI 2005 N. Ramangaseheno

  25. Filtering Tests (1/3) • L1 sameAs L2 : L1 and L2 are the same if • L1 isEqual L2 • or xb1 =xe2 ; yb1 =ye2 ; xe1 =xb2 ; ye1 =yb2 ; • in this case, line L2 is filtered (erased) l1 same as l2 PSI 2005 N. Ramangaseheno

  26. Filtering Tests (2/3) • L1 includes L2 : L1 includes L2 • case (a) : L2 totally included inside L1 • if L1 isColinear L2 • and L1 overlaps b2 • and L1 overlaps e2 • case (b) : L2 included inside and connected to L1 • or L1 isConnected L2 • and L1 isParallel L2 • and [ L1 overlaps b2 or L1 overlaps e2 ] (a) (b) l1 includes l2 PSI 2005 N. Ramangaseheno

  27. Filtering Tests (3/3) • L1 isJoined L2 : L1 and L2 join together • case (a) : L1 is extended by L2, without overlapping • if L1 isConnected L2 • and L1 isParallel b2 • and « L1 overlaps e2 » is false • case (b) : L1 is extended by L2, with overlapping • or L1 isColinear L2 • and L1 overlaps L2 • and L2 overlaps L1 (a) (b) l1 and l2 join together PSI 2005 N. Ramangaseheno

  28. Unformating SVG Documents • Presentation of the Project • Contributions • Diagram of the Unformat System • The SVG Format • Parsing • Modelling • Filtering • Intersection Search • Applications PSI 2005 N. Ramangaseheno

  29. Get Line Intersection (1/3) X junction T junction Segments separation Multi-degree junction PSI 2005 N. Ramangaseheno

  30. Get Line Intersection (2/3) Intersections processing algorithm • Search and list all junctions of the document, • For each line, test if it contains the junction • If yes, break the line in two at the junction point Used tests • L1 isIntersected L2 : L1 and L2 intersects themselves on a point p(x,y) • so that p <--L1 getIntersection L2 • case (a) : X junction • if p is not null • case (b) : T junction • if p is null • L1 overlaps p and L2 overlaps p • or L1 isConnected p and L2 overlaps p • or L2 isConnected p and L1 overlaps p • In both cases, add junction p(x,y) to the junctions list

  31. Get Line Intersection (3/3) • 2.L1 is regular, L2 irregular • Two cases: • L2 is horizontal • y1 = a1 * x1 + b1 ; • x2 = c; • - y2; • yc = c; • xc = (c - b1)/ a1 ; • L2 is vertical • y1 = a1 * x1 + b1 ; • y2 = c; • - x2; • xc = c; • yc = a1 * c + b1; • 3.L1 is irregular, L2 regular (see case 2.) • Two cases: • L1 is horizontal • L1 is vertical • L1 isIntersected L2 : returns • intersection point p(xc,yc) between lines L1 and L2 • null if lines are parralel or colinear • null if x<0 , y<0 • Four cases to take into account : • 1.L1 and L2are regular • y1 = a1 * x1 + b1 ; • y2 = a2 * x2 + b2 ; • yc = y1 = y2 ; • xc = x1 = x2 ; • xc = (b2 - b1)/(a1 - a2) ; • yc = a1 * xc + b1 = a2 * xc + b2 ; • 4.L1 and L2 are irregular (see case 2.) • Two cases: • L1 is vertical, L2 horizontal • L2 is vertical, L1 horizontal PSI 2005 N. Ramangaseheno

  32. Unformating SVG Documents • Presentation of the Project • Contributions • Applications PSI 2005 N. Ramangaseheno

  33. Experiments & Results (1/3) Unformating results on SVG documents created with the 2gT system ("graphic ground Truth"). PSI 2005 N. Ramangaseheno

  34. original SVG document unformated document after reduction of 20% Experiments & Results (2/3) • Colour index • black vectors : no change • red vectors : filtered vectors • blue vectors : « broken »vectors • «visually », all original lines are retrieved • After reduction, we do see that all intersections have been erased PSI 2005 N. Ramangaseheno

  35. Experiments & Results (3/3) • Algorithm complexity : n(n-1) • Filtering : n + (n-1) + (n-2) + … + 1 comparaisons • Intersections retrieval : n + (n-1) + (n-2) + … + 1 comparaisons • Runtime : about 1,5 min for 100 documents (2500 vectors and 100 intersections per document) PSI 2005 N. Ramangaseheno

  36. Conclusion • Outcome • Technical achievement • Unformating system effective and functional Perspectives Use upstream pattern recognition tools PSI 2005 N. Ramangaseheno

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