Image processing how do I erode on boundary and dilate inside boundary?

1. How is erosion and dilation performed in an image?
2. How do I extract boundaries from an image?
3. Why do we require erosion and dilation?

How is erosion and dilation performed in an image?

Dilation adds pixels to the boundaries of objects in an image, while erosion removes pixels on object boundaries. The number of pixels added or removed from the objects in an image depends on the size and shape of the structuring element used to process the image.

How do I extract boundaries from an image?

If A is an image and structuring element is B then Boundary Extraction can be given as, Boundary (A) = A - (A Ɵ B) Hence, it would give a pixel difference.

Why do we require erosion and dilation?

The most basic morphological operations are: Erosion and Dilation. They have a wide array of uses, i.e. : Removing noise. Isolation of individual elements and joining disparate elements in an image.