The document discusses geometry-based image abstraction techniques with applications in vectorization, highlighting methods such as geometric primitives and stylization operations to reproduce artistic styles with fabrication devices. It presents classifications of stylization techniques and operations, as well as examples of their implementation, such as vectorized pencil hatching and segment-based shape packing. The work aims to develop a framework that combines geometry and pixel-based stylization techniques for various artistic applications.

1. Design Space of Geometry-based Image Abstraction
Techniques with Vectorization Applications
Lisa Ihde1, Amir Semmo2, Jürgen Döllner1, and Matthias Trapp1
1Hasso Plattner Institute, Faculty of Digital Engineering, University of Potsdam, Germany
2Digital Masterpieces GmbH, Potsdam, Germany
30th International Conference on Computer Graphics, Visualization and Computer Vision 2022 (WSCG 2022)
This work was partially funded by the German Federal Ministry of Education and
Research (BMBF) through grants 01IS18092 ("mdViPro") and 01IS19006 ("KI-LAB-ITSE")

2. Reproduce results of image-stylization techniques with fabrication devices
such as plotter or laser cutters.
Motivation
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Example: vectorized pencil-hatching (Praun, 2001) as digital rendering and plotted result.

3. Geometry-based Stylization Techniques (GST)
➔ Image stylization using a number of geometric primitives
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[Geometric
Abstraction
III
Toned
Poster
by
David
Gordon]
[http://linify.me]
[https://www.evilmadscientist.com/201
2/stipplegen2/]
[http://paperjs.org/examples]
[https://tylerxhobbs.com/essays/2016/a-randomized-approach-to-circle-packing]

4. Design Space Overview
for Geometry-based Stylization Techniques

5. Bertin’s Visual Variables (1967, 1983)
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[https://volaya.github.io/gis-book/en/Visualization.html]
➔ Aspects of a graphical object for visual differentiation
Shape Hue
Value
Position Size Orientation
Texture

6. 1. Shape Types
Polygon
Proposed GST Design Space
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2. Outline 3. Fill
4. Shape Size 5. Shape
Orientation
6. Shape Type
Mixture
7. Shape
Placement
8. Placement
Approach
None Sketchy Regular None Solid Gradient Texture
Uniform
Non-
uniform
Uniform
Non-
uniform
Uniform
Non-
uniform
Local
Global
Point Line
Straight Line Polyline Curve
Convex Polygon Regular Polygon
Concave Polygon
Over
lapping
Non-over
lapping

7. Exemplary Classification of GSTs
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▪ 30 artists that use
geometry-based
abstraction in their
artwork
▪ Identified 15
Geometric
Stylization
Techniques

8. Classification of Processing
Techniques for GSTs

9. Classification of Stylization Operations
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Vector
(V)
Raster
(R)

10. Classification of Stylization Operations
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Geometric Primitives with Appearance information
Number of Raster Data Layers
Texturing / Rasterization
Raytracing
INPUT
OUTPUT
EXAMPLES
➔ Vector-2-Raster (V2R)
Vector
(V)
Raster
(R)
V2R

11. Raster-data Layers
Geometric Primitives with Appearance information
Tracing / Vectorization
Diffusion Curves
Classification of Stylization Operations
17th May 2022 Design Space of Geometry-based Image Abstraction Techniques with Vectorization Applications 11
INPUT
OUTPUT
EXAMPLES
➔ Raster-2-Vector (R2V)
Vector
(V)
Raster
(R)
V2R
R2V

12. Geometric Primitives with Appearance information
Geometric Primitives with Appearance information
Primitive Filtering
Geometry Amplification
Tessellation | Subdivision
Geometric Mapping Stages
Classification of Stylization Operations
17th May 2022 Design Space of Geometry-based Image Abstraction Techniques with Vectorization Applications 12
INPUT
OUTPUT
EXAMPLES
➔ Vector-2-Vector (V2V)
Vector
(V)
Raster
(R)
V2V V2R
R2V

13. Raster Data Layers (Color + Depth + Normal)
vs. (Segments + Structure + Flow)
vs. Temporal Windows
Number of Raster Data Layers
Image Segmentation
Neural Style Transfer (NST)
Classical Stylization Approaches
Blending / Compositing
Classification of Stylization Operations
17th May 2022 Design Space of Geometry-based Image Abstraction Techniques with Vectorization Applications 13
INPUT
OUTPUT
EXAMPLES
➔ Raster-2-Raster (R2R)
Vector
(V)
Raster
(R)
R2R
V2V V2R
R2V

14. Applications & Discussion

15. Vectorized Pencil Hatching
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Comparison of raster-based and vectorized pencil hatching.

16. Vectorized Pencil Hatching
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Praun,
2001
Tonal Art Maps (TAMs):

17. Segment-based Shape Packing
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Image Segmentation
with Mask R-CNN model trained on
Microsoft Coco dataset
Input Image Segment-based Shape Packing
(Collins, 2003)

18. Segment-based Shape Packing
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Working Principle: Place shapes of various dimensions in a
confined space inside a segment without overlapping
FOR segment IN segments:
shapes[] = generateShapes(numShapes,minSize,maxSize)
FOR shape IN shapes:
trials = TRIALS
WHILE trials-- > 0:
position = generatePosition()
IF isInsideSegment(shape,position,segment)
&& !collisionPlacedShapes(shape,position):
placeShape(shape,position)

19. Segment-based Shape Packing
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Plotter Software “Silhouette Studio”
Plotted result with scratching tool
count: 4,750
shapes
plotting time: 2.5h
size of shapes: 0.6-
3.5mm

20. Scribbled Line Art
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Principle: Blending/overlay lines based on brightness
pos = randomPosition()
addPosToPath()
count = 0
WHILE loopCount-- > 0
offset = calculateOffsetBasedOnNeighborsBrightness()
rotation = calculateRotationWithPerlinNoise()
pos += offset * rotation
count++
IF count < MAX_COUNT
addPosToPath()
fadePixelsOfPath()
ELSE
addPathAsLineItemAndResetCount()
findNextStartPosBasedOnBrightness()

21. Fused Stylization Techniques

22. Fused Stylization Techniques
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“Abstract Landscapes” by Jason Anderson
“Golden” (2019/2020) “Plaid” (2020)
“Matrix” (2019)

23. Fused Stylization Techniques
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Placed shapes: 29.417
Shape Packing Oil Painting
(Semmo, 2016)

24. Fused Stylization Techniques
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Placed shapes: 3.869
Scribbled Line Art Oil Painting
(Semmo, 2016)

25. Wrap Up
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1. Concept, classification, and semiotic for geometry-based stylization techniques
2. Framework for geometry-based stylization techniques that demonstrate
different applications
3. Development of operations for fused stylization techniques:
combining geometry and pixel-based stylization techniques

26. Questions?
26
17th May 2022 Design Space of Geometry-based Image Abstraction Techniques with Vectorization Applications

27. Design Space of Geometry-based Image Abstraction
Techniques with Vectorization Applications
Lisa Ihde1, Amir Semmo2, Jürgen Döllner1, and Matthias Trapp1
1Hasso Plattner Institute, Faculty of Digital Engineering, University of Potsdam, Germany
2Digital Masterpieces GmbH, Potsdam, Germany
30th International Conference on Computer Graphics, Visualization and Computer Vision 2022 (WSCG 2022)
This work was partially funded by the German Federal Ministry of Education and
Research (BMBF) through grants 01IS18092 ("mdViPro") and 01IS19006 ("KI-LAB-ITSE")
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