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Unformatted text preview: he grid. This technique of creating “runs” of 1s
and 0s is often used as a first pass analysis to partition the image into identifiable segments of
“blobs”. This procedure might not be able to identify small details in the object. This can be
resolved by decreasing the grid size and hence increasing the accuracy with which the image is
For a simple image such as a dark blob on a light background, a runs technique can provide
useful information. For more complex images, this technique may not provide an adequate
partition of an image into a set of meaningful regions. Such regions might contain pixels that are
connected to each other and have similar attributes, for example, gray level.
A region growing technique for complex images could have the following procedure:
1. Select a pixel that meets a criterion for inclusion in a region. In the simplest case this could
mean select white pixel and assign a value of 1
2. Compare the pixel selected with all the adjacent pixels. Assign an equivalent value to
adjacent pixels if an attribute match occurs.
3. Go to an equivalent adjacent pixel and repeat process until no equivalent pixels can be added
to the region.
This simple procedure of “growing” regions around a pixel would be repeated until no new
regions can be added for the image. Faculty of Engineering Robotics Technology MECH 4041 20
B.Eng (Hons.) Mechatronics S. Venkannah Mechanical and Production Engineering Department Region growing segmentation
Region-based segmentation: direct construction of regions. It is easy to construct regions from
their borders and it is easy to detect borders of existing regions. Segmentations resulting from
edge-based methods and region growing methods are not usually exactly the same. Combination
of results may often be a good idea.
Region growing techniques are generally better in noisy images where edges are extremely
difficult to detect.
Homogeneity of regions is used as the main segmentation criterion in region growing.
The criteria for homogeneity:
• gray level
• color, t...
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This document was uploaded on 03/12/2014 for the course MECHANICAL 214 at University of Manchester.
- Spring '14