Image Sharpening using Laplacian

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Image Sharpening using Laplacian

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Image Sharpening using Laplacian

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1. Image Sharpening using Laplacian The Laplacian is a 2-D isotropic measure of the second spatial derivative of an image. Course Name: Digital Image Processing Level: UG Authors Phani Swathi Chitta Mentor Prof. Saravanan Vijayakumaran *The contents in this ppt are licensed under Creative Commons Attribution-NonCommercial-ShareAlike 2.5 India license

2. Learning Objectives After interacting with this Learning Object, the learner will be able to: • Explain how the sharpening of an image is done using Laplacian

3. Definitions of the components/Keywords: 1 • The Laplacian of an image highlights regions of rapid intensity change and is therefore often used for edge detection. • Laplacian is very useful in detecting abrupt changes. • The Laplacian is often applied to an image that has first been smoothed in order to reduce its sensitivity to noise. • The Laplacian is defined as 2 3 4 5

4. Definitions of the components/Keywords: • Filter Masks for Laplacian: • Fig. A Fig. B Fig. C • Fig. D Fig. E Fig. F • If the mask used has a negative centered coefficient (Fig. A, B, C), subtract Laplacian Image from the Input Image to obtain a sharpened Image. • If the mask used has a positive centered coefficient (Fig. D, E, F), • add Laplacian Image to the Input Image to obtain a sharpened Image. 1 2 3 4 5

5. Master Layout 1 The Blurred Image Image after sharpening 2 3 • Give 3 radio buttons of filter masks so that user can select any one filter mask. • The three filter masks a, b, c are given below 4 5

6. Filter mask a Step 1: 1 2 3 4 5

7. Step 2: Filter mask b 1 2 3 4 5

8. Step 3: Filter mask c 1 2 3 4 5

9. Electrical Engineering Slide 1 Slide 3 Slide 10, 11,12 Slide 13 Introduction Definitions Analogy Test your understanding (questionnaire)‏ Lets Sum up (summary)‏ Want to know more… (Further Reading)‏ Interactivity: Try it yourself • Select any one of the figures • a b • c d • Select the filter size 9 Credits

10. Questionnaire 1 1.What is the value of the yellow box after Laplacian filter mask is applied? Answers: a) 3 b) 0 c) 1 d)‏ 9 2 3 4 5

11. Questionnaire 1 2. What are the values of yellow boxes after Laplacian filter mask is applied? Answers: a)b) 2 3 4 5

12. Questionnaire 1 2. What are the values of yellow boxes after Laplacian filter mask is applied? Answers: c) d) 2 3 4 5

13. Links for further reading Reference websites: http://homepages.inf.ed.ac.uk/rbf/HIPR2/log.htm Books: Digital Image Processing- Rafael C. Gonzalez, Richard E. Woods, second edition, Pearson Education Research papers: