1. Line Extraction Using 2D Laser Range Finder
By PSK

2. Index Objective 6 Algorithms and comparison Split and Merge
Proposed Algorithm
Result
Future Work

3. Objective How many lines are there? Which points belong to which line?
Given the points that belong to a line, how to estimate the line model parameters?

4. 6 line extract algorithm
Split-and-merge
Incremental
Hough-Transform
Line-Regression
RANSAC EM

5. Comparison
# Viet Nguyen, Agostino Martinelli, Nicola Tomatis, Roland Siegwart “A Comparison of Line Extraction Algorithms using 2D Laser Rangefinder for Indoor Mobile Robotics” Auton Robot (2007)

6. Split and Merge Algorithm

7. Proposed Algorithm

8. Find corner (double threshold)
angle2
angle1
angle2
angle1
First Threshold
Second Threshold
Using point-to-point angle
|angle1 – angle2| > threshold
→ corner

9. Merits and Demerits Merits Demerits Low Complexity : N*logN N
(N : number of points)
Demerits
Not robust
Threshold dependent

10. Possible Problem
오차로 인하여 코너가 직각이 되지 않는 경우
코너를 정확히 찾지 못하는 경우

11. Emphasis Corner
Theta resolution 0.7

12. Experiment Using 2D laser sensor (SICK), obtain data Parameter setting
Angle Threshold : 70°
Distance Threshold : 1cm
P2P Distance Threshold : 30
Minimum Set number : 9

13. Result1 (Split and Merge)

14. Result1 (Hough)

15. Result1 (Proposed)

16. Result2 (Split and Merge)

17. Result2 (Hough)

18. Result2 (proposed)

19. Future Work Improve corner detection
Finding Another corner detection method
Analysis Data