1. Project Presentation Convex Hull Problem
Radhika Bibikar
CSE 5311
Dr. Gautam Das

2. Introduction Convex Hull Algorithms:
Smallest enveloping polygon of N different points
Algorithms:
Graham Scan
Jarvis March
Divide and Conquer

3. Algorithms Graham’s Scan Phases: Complexity – O(n logn)
Select anchor point p0
Sort by polar angle with
respect to p0
Scan counter clockwise
maintaining the stack

4. Algorithms Jarvis March Phases: Complexity – O(n logn)
Select lowest and
highest points
Form right chain with
respect to polar angle
Form left chain with
respect to polar angle to
negative x - axis

5. Algorithms Divide and Conquer Phases : Complexity – O(n logn)
Sort points with respect
to x
Divide points in equal
subsets and recursively
find convex hulls
Merge hulls using upper
and lower tangents

6. Convex Hull Applications
Computer visualization
Visual pattern matching
Geographical Information Systems
(GIS)
Path finding

7. Onion Convex Hull
A sequence on nested convex hull are called the onion- peeling
Applications:
Study of Earth atmosphere
Network protocols (CDMA)
Image Processing
Secure Fingerprinting

8. Onion Triangulation Rotating Calipers – linear time algorithm
Applications:
Fingerprint Identification
Motion Planning

9. DEMO