1. Resolving Ambiguities to Create a Natural Sketching Environment Christine Alvarado and Randall Davis MIT AI Laboratory

2. Christine Alvarado Our Model The Designer Sketches with Pen and Paper The Observer Interprets the Sketch The Observer and Designer Interact

3. Christine Alvarado Sketch Interpretation

4. Christine Alvarado Accuracy vs. Freedom Drawing Freedom Recognition Difficulty Menu “Put That There” Single Stroke Recognition Free Sketch ASSIST

5. Christine Alvarado Accuracy and Freedom Smarter interpretation increases accuracy Better interaction design increases perceived freedom

6. Christine Alvarado Resolving Ambiguities Levels of Interpretation Fluid Interpretation Commitment to an Interpretation

7. Christine Alvarado 3 Stages of Interpretation Recognition Reasoning Resolution

8. Christine Alvarado Recognition Generate All Possible Interpretations: –Circle –Circular Body –Pin Joint

9. Christine Alvarado Reasoning: Heuristics Temporal Evidence Simpler Is Better Context Domain Knowledge User Feedback

10. Christine Alvarado Reasoning: Heuristics Temporal Evidence Simpler Is Better Context Domain Knowledge User Feedback

11. Christine Alvarado Reasoning: Heuristics Temporal Evidence Simpler Is Better Context Domain Knowledge User Feedback 1 arrow or 3 rods?

12. Christine Alvarado Reasoning: Heuristics Temporal Evidence Simpler Is Better Context Domain Knowledge User Feedback

13. Christine Alvarado Reasoning: Heuristics Temporal Evidence Simpler Is Better Context Domain Knowledge User Feedback

14. Christine Alvarado Reasoning: Heuristics Temporal Evidence Simpler Is Better Context Domain Knowledge User Feedback

15. Christine Alvarado Reasoning: Heuristics Temporal Evidence Simpler Is Better Context Domain Knowledge User Feedback Total Score

16. Christine Alvarado Resolution

17. Christine Alvarado Resolution 0 3 6

18. Christine Alvarado Resolution 0 3 6

19. Christine Alvarado Resolution 0 0 55 10

20. Christine Alvarado Resolution 0 5 10 0 5

21. Christine Alvarado Resolution 0 000 3 10 3 6 3 6 3 6 6

22. Christine Alvarado Resolution 0 000 3 10 3 6 3 6 3 6 6

23. Christine Alvarado Resolution 0 000 3 10 3 6 3 6 3 6 0 3 6 6 8

24. Christine Alvarado Resolution 0 000 3 10 3 6 3 6 3 6 0 3 6 6 8

25. Christine Alvarado Resolution 0 000 3 10 3 6 3 6 3 6 0 3 6 6 8

26. Christine Alvarado Relies heavily on bottom-up recognition Limitations line ??? Line + Line + Line + ???  ???

27. Christine Alvarado Relies heavily on bottom-up recognition Heuristics all weighted equally Limitations H1: H2:Prefer objects drawn with contiguous strokes Prefer interpretations resulting in fewer objects

28. Christine Alvarado Relies heavily on bottom-up recognition Heuristics all weighted equally Limitations H1: H2:Prefer objects drawn with contiguous strokes Prefer interpretations resulting in fewer objects

29. Christine Alvarado Relies heavily on bottom-up recognition Heuristics all weighted equally Limitations H1: H2:Prefer objects drawn with contiguous strokes Prefer interpretations resulting in fewer objects

30. Christine Alvarado Structured Application of Context Blackboard recognition architecture Heuristics applied probabilistically

31. Christine Alvarado Recognition Blackboard Sketch Blackboard Line(l1)Line(l2)Line(l3) Line(l5)Line(l4)Line(l7) Connects(l1, l2) Arrow(a1) Force(f1) Stroke(s2)Stroke(s1)Stroke(s3)Stroke(s5)Stroke(s7)Stroke(s6)Stroke(s4) Connects(l4, l5) Connects(l7, l4) Forces push bodies Line(l6) Connects(l5, l6) Connects(l6, l7) Polygon(p1) Body(b1)

32. Christine Alvarado Bayesian Network Structure Heuristics influence prior Line1Line2Line3 Property1Property2 … … Low-level information influences recognition

33. Christine Alvarado Related Work Gross and Do (1996) Landay and Meyers (2001) Stahovich (1998) Matsakis (1999)