CVL – GIST, Korea Date : Presenter : Dae-Yong Cho

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

CVL – 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

CVL – GIST, Korea4  Otsu  Sauvola  Niblack  Bernsen

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

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

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

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

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

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

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

CVL – GIST, Korea12CVL – GIST, Korea I To overcome Otsu’ algorithm’s problem

CVL – GIST, Korea13CVL – GIST, Korea Local Threshold Value t(x,y)

CVL – GIST, Korea14CVL – GIST, Korea Local Threshold Value

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

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

CVL – GIST, Korea17 1.WikiPedia : 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 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.

CVL – GIST, Korea18CVL – GIST, Korea