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Erosion. The basic morphological operations applied to either grayscale or binary images are Erosion and Dilation. Erosion shrinks image objects while dilation expands them. Course Name: Digital Image Processing Level(UG/PG): UG Author(s) : Phani Swathi Chitta
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Erosion The basic morphological operations applied to either grayscale or binary images are Erosion and Dilation. Erosion shrinks image objects while dilation expands them. • Course Name: Digital Image Processing Level(UG/PG): UG • Author(s) : Phani Swathi Chitta • Mentor: Prof. Saravanan Vijayakumaran *The contents in this ppt are licensed under Creative Commons Attribution-NonCommercial-ShareAlike 2.5 India license
Learning Objectives After interacting with this Learning Object, the learner will be able to: • Explain the basic morphological operation (Erosion)
Definitions of the components/Keywords: • Characteristics of Erosion - Erosion generally decreases the sizes of objects and removes small irregularities by subtracting objects with a span smaller than the structuring element. - With grayscale images, erosion reduces the brightness (and therefore the size) of bright objects on a dark background by taking the neighborhood minimum when passing the structuring element over the image. - With binary images, erosion completely removes objects smaller than the structuring element and removes perimeter pixels from larger image objects. • The erosion operator takes two pieces of data as inputs. - The first is the image which is to be eroded. - The second is a (usually small) set of coordinate points known as a structuring element (also known as a kernel). • It is this structuring element that determines the precise effect of the erosion on the input image. • In erosion, every object pixel that is touching a background pixel is changed into a background pixel Erosion makes the objects smaller, and can break a single object into multiple objects. 1 2 3 4 5
Master Layout 1 1 Image after erosion Original Image 2 3 • Give radio buttons to select any one structuring element of sizes 5x5, 7x7, 11x11 • The structuring elements (SE) are square and round 4 5
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Electrical Engineering Slide 1 Slide 3 Slide 23, 24,25 Slide 26 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 structuring element 12 Credits
Questionnaire 1 1.After eroding the image, will the number of background pixels increase or decrease? Answers: a) Increase b) Decrease 2 3 4 5
Questionnaire 1 2. Image a Image b:Structuring Element What is the resulting image after eroding the image a using structuring element (image b)? Answers: a) b) 2 3 4 5
Questionnaire 1 2. Image a Image b:Structuring Element What is the resulting image after eroding the image a using structuring element (image b)? Answers: c)d) 2 3 4 5
Links for further reading Reference websites: http://siri.lmao.sk/fiit/DSO/Prednasky/2a Morphological processing Recap & Extend / Digital Image Processing Lecture Morphological processing Recap &Extend.pdf http://en.wikipedia.org/wiki/Erosion_%28morphology%29 http://homepages.inf.ed.ac.uk/rbf/HIPR2/erodedemo.htm http://homepages.inf.ed.ac.uk/rbf/HIPR2/erode.htm Books: Digital Image Processing – Rafael C. Gonzalez, Richard E. Woods, Third edition, Prentice Hall