1. CVL – Daeyong @ GIST, Korea Date : 2014. 11. 18 Presenter : Dae-Yong Cho

2. CVL – Daeyong @ GIST, Korea2  What is binarization?  Binarization Method Otsu’s Sauvola’s  References

3. CVL – Daeyong @ GIST, Korea3 Divide image’s intensities into 0 or 255 (Foreground and Background ) Color Image Gray Image Binary Image Thresholding Used for OCR System to segment characters from background

4. CVL – Daeyong @ GIST, Korea4  Otsu  Sauvola  Niblack  Bernsen

5. CVL – Daeyong @ GIST, Korea5 1. Compute histogram of input image (Assumption : There are only two classes in histogram)

6. CVL – Daeyong @ GIST, Korea6 (Assumption : There are only two classes in histogram) Histogram Gray Scale Image

7. CVL – Daeyong @ GIST, Korea7 1. Compute histogram of input image (Assumption : There are only two classes in histogram)

8. CVL – Daeyong @ GIST, Korea8 1. Compute histogram of input image (Assumption : There are only two classes in histogram)

9. CVL – Daeyong @ GIST, Korea9 1. Compute histogram of input image (Assumption : There are only two classes in histogram)

10. CVL – Daeyong @ GIST, Korea10 Result Input Image Otsu Alg. Output

11. CVL – Daeyong @ GIST, Korea11 Result Input Image Otsu Alg. Output Effect of Global Method

12. CVL – Daeyong @ GIST, Korea12CVL – Daeyong @ GIST, Korea I To overcome Otsu’ algorithm’s problem

13. CVL – Daeyong @ GIST, Korea13CVL – Daeyong @ GIST, Korea Local Threshold Value t(x,y)

14. CVL – Daeyong @ GIST, Korea14CVL – Daeyong @ GIST, Korea Local Threshold Value

15. CVL – Daeyong @ GIST, Korea15CVL – Daeyong @ GIST, Korea Input Image Sauvola Alg. Output (with k = 0.5) Result

16. CVL – Daeyong @ GIST, Korea16CVL – Daeyong @ GIST, Korea Input Image Sauvola Alg. Output (Elapsed time : 484msec) Comparison Otsu Alg. Output (Elapsed time : 16msec)

17. CVL – Daeyong @ GIST, Korea17 1.WikiPedia : http://en.wikipedia.org/wiki/Otsu's_methodhttp://en.wikipedia.org/wiki/Otsu's_method 2.T. Romen Singh, Sudipta Roy, O. Imocha Singh, Tejmani Sinam, and Kh. Manglem Singh, “A New Local Adaptive Thresholding Technique in Binarization”, International Journal of Computer Science Issuses(IJCSI), Vol. 8, Issue 6, No 2, November 2011. 3.Faisal Shafait, Daniel Keysers, and Thomas M. Breuel, “Effiecient Implementation of Local Adaptive Thresholding Techniques Using Integral Images”, International Society for Optics and Photonics(SPIE), 2008.

18. CVL – Daeyong @ GIST, Korea18CVL – Daeyong @ GIST, Korea