1. A Pixel-Weighting Method for Discriminating Objects of Different Sizes in an Image Captured from a Single Camera Mookyung Park, Namsu Moon, Sangrim Ryu, Jeongpyo Kong, Yongjin Lee and Wangjin Mun S1 Corporation, Korea

2. Customer site Alarm signal Centralized control office Instruction Visit Security agent Cost ∝ Number of visits Security Service Flow

3. PIR sensor ( Passive Infra-Red ) False alarm Cost ￪ Lacks intelligence More Intelligence Vision sensor + Image processing Stereo : expensive Single : cost-effective  useful feature for discriminating objects Object size This talk is on a method of how to calculate the size of objects in an image captured from a single camera Single : cost-effective Objectives

4. Object A A BC B C Object A A BC B C Proper weight of pixel  Real size of objects Objects in the images

5. pixel (x,y) H x,y H x,y-1 VyVy trapezoid Overview of Calculation

6. The object is standing perpendicularly to the ground and is not floating in the air. 1 st. The camera is installed at high location looking down objects like humans. 2 nd. 3 rd. The camera kept in a horizontal position, not tilting to the right of the left. The effect of radial distortion of lens does not appear in the image. 4 th. Assumptions

7. hehe Blind zone ABAB AVAV AVHAVH 123HH-1 hehe Blind zone angle Blind zone ABAB AVAV AVHAVH W 123HH-1 H 1 2 3 H Vertical pixel number Blind zone Blind zone AHAH AHWAHW 123 W2W2 21 W2W2 1 23 W2W2 12 W2W2 Even symmetry Horizontal pixel number Blind zone AHAH AHWAHW 123 W2W2 21 W2W2 Camera lens Horizontal angle of view AHAH Vertical angle of view AVAV Installation Blind zone angle ABAB Height of Installation hehe Image size Horizontal pixel number W Vertical pixel number H Height of Installation Vertical angle of view Horizontal angle of view Parameters Required

8. A x,y = ×V y × ( H x,y + H x,y-1 A x,y = ×V y × ( H x,y + H x,y-1 ) AVHAVH AVHAVH X y θyθy H 1 2 H W hehe ABAB AVAV vyvy L y-1 LyLy y bottom CyCy y θyθy θyθy 12121212

9. A x,y = ×V y × ( H x,y + H x,y-1 A x,y = ×V y × ( H x,y + H x,y-1 ) 12121212 CyCy θyθy hehe LyLy CyCy CyCy CyCy CyCy CyCy CyCy Pixel (x,y) D x-1,y D x,y H x,y H x,y- 1 VyVy AHWAHW AH2AH2 CyCy

10. Final Formula Representing the Weight

11. Experimental set-up Experimental Verification Reference image Current image DifferenceBinarization Noise Filter Labeling Weighting

12. Experimental Results (1) ab c d e b31565574c41085454d5785306e6625821 a22345241 DistancePixelsWeight sum For the same object with different locations

13. For objects of different sizes Experimental Results (2) Small animal Human Small animal Human a88 26285761 PixelsWeight sum b5618621445682c3533922435919 a b c Human Small animal

14. Summary Operational cost caused by false alarms can be significantly suppressed by adopting intelligent vision-based sensors in our security service business Considering cost-effectiveness, we proposed a method of calculating the size of the object in the image captured from single camera The calculation of object size requires parameters which are obtained when installing the vision sensor (camera) Experimental results show that the proposed method produces a useful feature for distinguishing objects of different sizes