Objectbased Vectorization for Interactive Image Editing

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Object-based Vectorization for Interactive Image
Editing

• Brian Price and William Barrett
• Brigham Young University

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What is vectorization?

• Traditional vectorization involves fitting curves
  to binary raster line images.

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Object-based Vectorization

• Object-based vectorization creates and renders
  meshes extracted from individual objects
  contained in grayscale or color raster images.

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Applications

• Creating editable graphics from photographs
• Layered object editing
• Reverse-engineering graphics

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Related Works

• Current Vectorization Techniques
• Adobe Illustrator Live Trace
• Macromedia Flash
• Corel CorelTRACE
• Siame Vector Eye
• Autotrace

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Related Works

• Image Segmentation
• Intelligent Scissors (Mortensen, Barrett 1995)
• Intelligent Paint (Reese 2002)
• Min Graph Cut Techniques
• Boykov and Kolmogorov 2001
• Lazy Snapping (Li et al 2004)
• GrabCut (Rother et al 2004)

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Related Works

• Image Editing
• Commercial Products (Photoshop, The Gimp)
• Object-based Image Editing (Cheney, Barrett)
• Texture Synthesis
• Texture Synthesis by Non-parametric Sampling
  (Efros, Leung)
• Inpainting (Bertalmio)
• Non-photorealistic Rendering
• Stylization of Photographs (DeCarlo, Santella)
• Paint by Relaxation (Hertzmann)

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Video
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Method
Select Object
Original
Create mesh
Final Render
Subobject Segmentation
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Object Selection

• Interactive graph cut
• Continuous foreground seeding (background
  pre-seeded)
• Selected object updated with each mouse stroke
• Immediate user feedback

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Mesh Creation

• Find corners
• Create mesh recursively
• Render

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Mesh Creation

• Find corners
• Create mesh recursively
• Render

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Mesh Creation

• Find corners
• Create mesh recursively
• Render

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Mesh Creation

• Find corners
• Create mesh recursively
• Render

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Automatic Recursive Subobject Segmentation
Render coarsely
Assemble final render
Fill background


Create new foreground objects
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Layered Object Hierarchy

• Allows hierarchical control of objects
• Edits on parent objects automatically propagated
  to children objects

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Background fill

• Rows and columns of mesh filled using least
  squares fit to both interpolate and extrapolate
  across occluded regions

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Object Editing
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Progressive Levels of Detail
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Results
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Results

• Comparison to other Vectorization Techniques
• Top - Image Vectorization
• Bottom Adobe Illustrator

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Results

• Comparison to other Vectorization Techniques
• Top - Image Vectorization
• Bottom Macromedia Flash

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Results

• Comparison to other Vectorization Techniques
• Top - Image Vectorization
• Bottom Siame Vector Eye

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Results - Reverse Engineering

• Created by artist with Adobe Illustrator

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Results - Reverse Engineering

• Vector graphic created from raster image

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Results - Reverse Engineering

• Resulting rendering

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Results - Reverse Engineering
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Results - Reverse Engineering
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Results - Reverse Engineering
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Results - Editing
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Results - Editing
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Results - Editing
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Results - Editing
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Results Level of Detail
Level 0 133 Patches 5.73 error per pixel
Level 5 2984 Patches 2.81 error per pixel
Level 2 1361 Patches 3.40 error per pixel
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Contributions

• Fully layered editable object-based vector
  graphic from a raster image
• Hierarchical object tree
• Automatic recursive subobject segmentation
• Improvements to min graph cut user segmentation

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Limitations

• Complex Textures
• Revert to OBIE-style textures
• Procedural textures
• Seams created from gaps between adjacent regions
• Complex Shapes
• Better representation of such objects

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Future Work

• Explore higher-order texture-based background
  filling
• Support complex shapes
• Automatic segmentation without vectorization
• Video vectorization

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Conclusion

• Works well on a variety of objects
• Captures natural shading better than current
  vectorization techniques
• Provides advanced hierarchical object control