1. Simulating Decorative Mosaics Based on SIGGRAPH ‘01 paper by Alejo Hausner mteh@andrew.cmu.edu 15-463 Final Project

2. Agenda Background + Objective Technique Results

3. Background + Objective Based on SIGGRAPH '01 paper on "Simulating Decorative Mosaics" by Alejo Hausner. "Simulating Decorative Mosaics" by Alejo Hausner http://dl.acm.org/citation.cfm?id=383327 To simulate decorative tile mosaics in an aesthetically-pleasing way.

4. Technique – About Tiled Mosaics Random but uniform distribution of tiles – Gap between tiles uniform Tile color should represent image Tiles should be oriented according to edges Image from http://flickriver.com/photos/johnwilliamsphd/3352267021/http://flickriver.com/photos/johnwilliamsphd/3352267021/

5. Technique: Voronoi Diagram Hausner: use of graphics hardware z-buffer in order to approximate the voronoi diagram... Not possible in Matlab! Matlab: voronoin Euclidean distance instead of Manhatthan distance

6. Technique: Lloyd’s Algorithm Centroidal Voronoi Diagram Lloyd’s Algorithm: – Compute Voronoi diagram of points – Re-compute centroid of each cell – Move point to new centroid. Matlab limitation: “point-at-infinity problem”

7. Initial Prototype

8. Tile Orientation Use bwdist Calculate gradient to closest point on edge

9. Edge Avoidance/Discrimination Detect overlap, re-calculate centroid x x

10. Edge Avoidance/Discrimination BeforeAfter

11. Edge Artifacts User-drawn edge might be better Source: http://en.wikipedia.org/wiki/File:Tux.svg

12. pad_border() Added fake edge border

13. Clustering Problem Solution: Remove tiles with more than 10 px overlap Story Sunlight by Edward Hopper http://www.paintinghere.com/UploadPic/Edward%20Hopper/big/Second%20Story%20Sunlight.jpg http://www.paintinghere.com/UploadPic/Edward%20Hopper/big/Second%20Story%20Sunlight.jpg

14. Color Point color (noise/lossy?) Average of sample Hausner: "point samples work best for images with uniformly-coloured regions, while area samples suit continuous-tone images".

15. Color: Average vs Point A Wheat Field with Cypresses by Vincent van Gogh. http://en.wikipedia.org/wiki/A_Wheatfield_with_Cypresses

16. Future Work Vary tile size? – Smaller tiles for region of higher detail? Vary tile shape: triangle, circle?

17. Results http://www.adoptionblogs.com/media/ChinaAdoption/466px-Yin_yang-1.svg.jpg

18. Results Suprematist Composition by Kazimir Malevich http://en.wikipedia.org/wiki/Suprematist_Composition

19. Results A Wheat Field with Cypresses by Vincent van Gogh. http://en.wikipedia.org/wiki/A_Wheatfield_with_Cypresses

20. Results Vase with Fifteen Sunflowers by Vincent van Gogh http://en.wikipedia.org/wiki/Sunflowers_(series_of_paintings)

21. Results Too much detail? Bal du moulin de la Galette by Pierre-Auguste Renoir http://en.wikipedia.org/wiki/Bal_au_moulin_de_la_Galette,_Montmartre

22. Results Portrait of Joseph Roulin by Vincent van Gogh http://en.wikipedia.org/wiki/The_Roulin_Family_(Van_Gogh_series)

23. Results (Photos) HP Garage (Personal Archive)

24. Results (Photos) SCS Banner @ Wean Hall (Personal Archive)

25. Thank You Questions?