9 morphological image processing.ppt [相容模式]
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9 MORPHOLOGICAL IMAGE PROCESSING
Chih-Wei TangDepartment of Communication Engineering
National Central UniversityJhongLi, Taiwan
Outline• Preliminaries• Dilation and erosion• Opening and closing• Some basic morphological algorithms• Extensions to gray-scale images
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Basic Concepts from Set Theory
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• Sets: objects in an image• Set theory: the language of mathematical
morphology
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Translation and Reflection
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• They are extended from morphology but not found in basic texts on set theory.
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Outline
Preliminaries Dilation and erosion Opening and closing Some basic morphological algorithms Extensions to gray-scale images
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Translation
Use of Morphological Dilation for Bridging Gaps
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Use of Morphological Erosion for Removing Image Components
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Outline
Preliminaries Dilation and erosion Opening and closing Some basic morphological algorithms Extensions to gray-scale images
Opening and Closing• Opening
• smooth the contour of an object• breaks narrow isthmuses• eliminates thin protrusions
• Closing• smooth sections of contours• generally fuses narrow breaks and long thin gulfs• eliminates small holes• fills gaps in the contour
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Opening
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Closing
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Opening
Closing
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Use of Opening and Closing for Morphological Filtering
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Outline
Preliminaries Dilation and erosion Opening and closing Some basic morphological algorithms Extensions to gray-scale images
Boundary Extraction
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StructureElement
Erosion
Example – Boundary Extraction
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Region Filling
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Dilation
Complement
Example – Region Filling
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Extraction of Connected Components
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Converge!!!1 If kk XX
kXY Let
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Outline
Preliminaries Dilation and erosion Opening and closing Some basic morphological algorithms Extensions to gray-scale images
2-D Dilation
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• General effects• If all the values of the structuring element
are positive, the output image tends to be brighter than the input.
• Dark details either are reduced or eliminated, depending on how their values and shapes relate to the structuring element used for dilation.
1-D Dilation
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Correct?
2-D Erosion
• General effects• If all the elements of the structuring element
are positive, the output image tends to be darker than the input image.
• The effect of bright details in the input image that are smaller in area than the structuring element is reduced.
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1-D Erosion
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Correct?
Dilation and Erosion on A Gray-Scale Image
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Gray-Scale Opening and Closing
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Gray-Scale Opening and Closing –Example
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