PrerequisitesBefore starting this lesson, you should be familiar with:
Learning ObjectivesAfter completing this lesson, learners should be able to:
Design morphological filters using rank filters
Execute morphological filters on binary or grayscale images and explain the output
Filters can be used to change size and shape of objects in an image. [*] Concept map below assumes bright objects on dark background. For dark objects on bright background effect of min and max filters is inverted.
Open the image,
xy_8bit_binary_two_spots_different_size.tif, and explore how structures grow and shrink, using erosion and dilation
Fill in the blanks, using those words: “shrinks”, “increases”, “decreases”, “enlarges”.
- An erosion ___ objects in a binary image. 2. An erosion in a binary image ___ the number of foreground pixels. 3. A dilation in a grayscale image ___ the average intensity in the image. 4. A dilation ___ objects in a binary image.
True of false? Discuss with your neighbour!
- Morphological openings on binary images can decrease the number of foreground pixels. 2. Morphological closings on binary images never decreases the number of foreground pixels. 3. Performing a morphological closing a twice in a row does not make sense, because the second closing does not further change the image.
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