CONTINUOUS LINE DRAWINGS ON DENDRITES

Hua Li and David Mould

ARTECH 2012

CONTINUOUS LINE DRAWINGS

A sketching technique The pen will never leave the paper until

the picture is finished. Constraints:

a single closed curve no self-intersection preserving key features (tone and

structure)

RELATED WORK

Approaches to Traveling Salesman Problem (TSP) TSP art [Kaplan and Bosch 2005]

Curve on 2D manifolds [Pedersen and Singh 2006]

Unicursal maze [Pullen 2010] CLD on meshes or 3D models [Xing et

al. 2012, Garigipati and Akleman 2012]

PREVIOUS WORK

Curve on 2D manifolds [Pedersen and Singh 2006]

Unicursal maze [Pullen 2010]

TSP art [Kaplan and Bosch 2005]

Surface covering curves [Xing et al. 2012]

Duotone surfaces [Garigipati and Akleman 2012]

A KEY OBSERVATION TO OUR ALGORITHM

A tree structure An outer boundary forming a CLD

OVERVIEW OF OUR METHOD

A given image 1. Build a dendrite 2. Label a dentrite

3. Build a wall (blue)

4. Label and build (green)

5. Generate a CLD

STEP I: GENERATING A TREE STRUCTURE

1. A starting seed 2. The second stipple

3. The first dendrite

4. The third stipple 4. The second dendrite 5. The fourth stipple and the third dendrite

STEP II: FIRST LABELING PROPAGATION

A resulting tree from step I 1. Label each branch

2. Propagate labels and find a wall

3. Add image boundary as a wall

STEP II: SECOND LABELING PROPAGATION

1. Break the wall 2. Label the broken wall and the tree

3. Propagate labels and find the CLD

EXAMPLES OF SECOND LABELLING

VARIATIONS

Dense distribution Sparse distribution and a different position

Sparse distribution and parameter variations

VARIATIONS ON STARTING SEED

POST PROCESSING BY POV-RAY

COMPARISON

TSP art [Kaplan and Bosch 2005]

Our CLDOriginal image

MORE RESULTS

Dendrites CLD Jordan map

Original image Dendrites CLD

ENHANCEMENT WITH MASK AND THICKNESS

CONCLUSIONS

Propose an automatic abstraction with CLD

Our new idea can preserve structure and tone suggestions.

The CLD problem remains a very hard problem. Automatic balance between the quality of

abstraction and the aesthetic pleasure is still an unknown issue.

THANKS!

Questions?