1. LING 111 Teaching Demo By Tenghui Zhu (tz3d@cs.virginia.edu)tz3d@cs.virginia.edu Introduction to Edge Detection Image Segmentation

2. Overview Review on Image Data Structures Purpose of Image Segmentation Basic Image Segmentation Algorithm –Edge Detection

3. Overview Review on Image Data Structures Purpose of Image Segmentation Basic Image Segmentation Algorithm –Edge Detection

4. Image Data Structures grayscale images : (Center) each pixel = a value between 0 - 255. monochrome images: (Left) each pixel = a single 0 or 1 value Color Images: (Right) each pixel = three values (red, green and blue - RGB).

5. Image Data Structures grayscale images : (Center) each pixel = a value between 0 - 255. monochrome images: (Left) each pixel = a single 0 or 1 value Color Images: (Right) each pixel = three values (red, green and blue - RGB).

6. Overview Review on Image Data Structures Purpose of Image Segmentation Basic Image Segmentation Algorithm –Edge Detection

7. One Image Segmentation application

8. Any other Image Segmentation application ? Satellite Images for CIA Medical Images for NIH Face Recognize for FBI Etc…

9. Overview Review on Image Data Structures Purpose of Image Segmentation Basic Image Segmentation Algorithm –Edge Detection

10. Edge Detection — 3x3 Filtering

12. 5

13. Edge Detection Filters R 1 R 2 R 3 R 4

14. Edge Detection

16. Constrains of Edge Detection

17. Overview Review on Image Data Structures Purpose of Image Segmentation Basic Image Segmentation Algorithm –Edge Detection Next time, we will talk about another basic Image Segmentation Algorithm -- Histogram

18. Thank you !

21. Gray Scale Image - bimodal Image of a Finger Print with light background

22. Bimodal - Histogram Image Histogram of finger print

23. Segmented Image Image after Segmentation

24. Gray Scale Image - Multimodal Original Image of lena

25. Multimodal Histogram Histogram of lena

26. Segmented Image Image after segmentation – we get a outline of her face, hat, shadow etc

27. Colour Image - Multimodal Colour Image having multi-modal histogram

28. Histogram Image Histogram for the three colour spaces

29. Segmented Image

30. Overview Review on Image Segmentation –Algorithm (Without User Interaction) Edge Detection Statistics (Histogram etc…) –Tools (With User Interaction) Magic Wand Intelligent Scissors Graph Cut

31. Conclusions Conclusions GrabCut – powerful interactive extraction tool Iterated Graph Cut based on colour and contrast Regularized alpha matting by Dynamic Programming