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Dilation and erosion

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Aswin Pv
Aswin Pv

Morphological operations like dilation and erosion are non-linear image transformations used to extract shape-related information from images by processing objects based on their morphology or shape properties using a structuring element, with dilation adding pixels to object boundaries and erosion removing pixels from object boundaries. The size and shape of the structuring element controls the number of pixels added or removed during these operations, which are used for tasks like noise removal, feature extraction, and image segmentation.

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MORPHOLOGICAL OPERATIONS Dilation AND Erosion Brainbitz
Morphological operation • It is a collection of non-linear operations related to the shape or morphology of features in an image. • ie , we process images according to its shape • 2 fundamental operations Dilation Erosion Brainbitz
DILATION AND EROSION • Dilation adds pixels to the boundaries of objects in an image • Erosion removes pixels on object boundaries Brainbitz
DILATION • It grows or thicken objects in a binary image • Thickening is controlled by a shape referred to as structuring element • Structuring element is a matrix of 1’s and 0’s Brainbitz
Brainbitz
Brainbitz
Opening and Closing operations • Opening  An Erosion followed by a dilation • Closing  A dilation followed by an erosion Brainbitz
Brainbitz
Brainbitz
Structuring element • The number of pixels added or removed from the objects in an image depends on the size and shape of the structuring element • It’s a matrix of 1’s and 0’s • The center pixel of the structuring element, called the origin Brainbitz
Origin of a Diamond-Shaped Structuring Element Brainbitz
Dilation and erosion operation • It use hit or miss transformation • In the hit and miss transformation, an object represented by a set X is examined through a structural element represented by a set B. • The structuring element is a shaped matrix Brainbitz
Cont. • Miss  No changes • Hit  at least one pixel matches =>The origin is replaced by 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 0 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 Input matrix Structuring element Dilated matrix Brainbitz
Dilation in MATLAB • Syntax Y = imdilate(A,B) • A  input image • B  Structuring element • Y Dilated image Brainbitz
Structuring element in MATLAB • They can be easily created using ‘strel’ function se = strel ( shape , parameters ) • Shape can be ‘ diamond ’ , ’ square ’ , ’ disk ’ , ’ line ’ etc. Brainbitz
Erosion in MATLAB • It shrinks or thin objects in a binary image • Syntax se =imerode(A,B) • Output is 1 when element completely fits 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 Input matrix Structuring element Dilated matrix Brainbitz
Dilation program BW = zeros(9,10); BW(4:6,4:7) = 1 SE = strel('square',3) BW2 = imdilate(BW,SE) Brainbitz
Brainbitz
Brainbitz
Questions Brainbitz • Perform dilation and erosion

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Dilation and erosion

  • 1. MORPHOLOGICAL OPERATIONS Dilation AND Erosion Brainbitz
  • 2. Morphological operation • It is a collection of non-linear operations related to the shape or morphology of features in an image. • ie , we process images according to its shape • 2 fundamental operations Dilation Erosion Brainbitz
  • 3. DILATION AND EROSION • Dilation adds pixels to the boundaries of objects in an image • Erosion removes pixels on object boundaries Brainbitz
  • 4. DILATION • It grows or thicken objects in a binary image • Thickening is controlled by a shape referred to as structuring element • Structuring element is a matrix of 1’s and 0’s Brainbitz
  • 7. Opening and Closing operations • Opening  An Erosion followed by a dilation • Closing  A dilation followed by an erosion Brainbitz
  • 10. Structuring element • The number of pixels added or removed from the objects in an image depends on the size and shape of the structuring element • It’s a matrix of 1’s and 0’s • The center pixel of the structuring element, called the origin Brainbitz
  • 11. Origin of a Diamond-Shaped Structuring Element Brainbitz
  • 12. Dilation and erosion operation • It use hit or miss transformation • In the hit and miss transformation, an object represented by a set X is examined through a structural element represented by a set B. • The structuring element is a shaped matrix Brainbitz
  • 13. Cont. • Miss  No changes • Hit  at least one pixel matches =>The origin is replaced by 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 0 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 Input matrix Structuring element Dilated matrix Brainbitz
  • 14. Dilation in MATLAB • Syntax Y = imdilate(A,B) • A  input image • B  Structuring element • Y Dilated image Brainbitz
  • 15. Structuring element in MATLAB • They can be easily created using ‘strel’ function se = strel ( shape , parameters ) • Shape can be ‘ diamond ’ , ’ square ’ , ’ disk ’ , ’ line ’ etc. Brainbitz
  • 16. Erosion in MATLAB • It shrinks or thin objects in a binary image • Syntax se =imerode(A,B) • Output is 1 when element completely fits 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 Input matrix Structuring element Dilated matrix Brainbitz
  • 17. Dilation program BW = zeros(9,10); BW(4:6,4:7) = 1 SE = strel('square',3) BW2 = imdilate(BW,SE) Brainbitz
  • 20. Questions Brainbitz • Perform dilation and erosion