1. Barrier Coverage in Camera Sensor Networks ACM MobiHoc 2011 Yi Wang Guohong Cao Department of Computer Science and Engineering The Pennsylvania State University University Park, PA, USA

2. Outline Introduction System Model and Assumptions Proposed Protocol Simulation Conclusions

3. Introduction Barrier coverage has attracted much attention in the past few years However, most of the previous works focused on traditional scalar sensors The author propose to study barrier coverage in camera sensor networks Scalar sensorCamera sensor

4. Introduction Difference between camera and scalar sensor Cameras from different positions can form quite different views of the object Scalar sensorCamera sensor 0/1 SiSi SiSi SjSj SjSj

5. Introduction Simply combining the sensing range of the cameras across the field does not necessarily form an effective camera barrier

6. Introduction _ Goal The author propose a method to select camera sensors from an arbitrary deployment to form a camera barrier which is full-view coverage Also present redundancy reduction techniques to reduce the number of cameras used

7. System Model and Assumptions Camera sensors are deployed randomly to monitor a bounded region A A

8. System Model and Assumptions

9. A B

11. Overview s d

12. Proposed Protocol _Full-View for Points

13. V SiSi SjSj

14. Proposed Protocol _Full-View for Sub-Region V SiSi SjSj

15. R S1S1 S2S2 S3S3 S4S4 S5S5 S6S6 S7S7 Example:

16. Proposed Protocol _Full-View for Sub-Region Example:

17. Proposed Protocol _Problem of Different CL R S1S1 S2S2 S3S3 S4S4 S5S5 S6S6 S7S7 V

18. Example:

19. Proposed Protocol _Camera Selection Dijkstra’s Algorithm

20. Proposed Protocol _Reduction The method described above has one drawback Redundant cameras Redundant Node

21. Proposed Protocol _Reduction R2R2 1 Barrier If S 3 is also redundant node in R 2 Candidate Node

22. Proposed Protocol _Reduction R2R2 1 Barrier If S 3 is also redundant node in R 2 Candidate Node SkSk DG=(V, E) [16] V. T. Paschos. A δ/2-approximation algorithm for the maximum independent set problem. Information Processing Letter, 44(1):11–13, 1992.

23. Simulation Size of region 200m ＊ 100m 200m ＊ 200m DeploymentRadom and Uniform Parameters of camera ， ，

24. Simulation

29. Conclusions The author propose a method to select camera sensors from an arbitrary deployment to form a camera barrier which is full-view coverage Also present redundancy reduction techniques to reduce the number of cameras used

30. Thank you!!