Computer Vision- Segmentation by Region Growing and by Region Splitting and Merging

 Objective: Partition an image into regions

Region Growing- As the name implies, Region Growing is a procedure that groups pixels or subregions into larger regions based on predefined criteria for growth.

Basic Approach: Start with a set of "seed" points, and from these grow regions by appending to each seed those neighboring pixels that have predefined properties similar to the seed(such as ranges of intensity or color)

How many seeds? Which ones?

The procedure is to compute at every pixel the same set of properties that ultimately will be used to assign pixels to regions during the growing process. If the result of these computations shows clusters of values, pixels whose properties place them near the centroid of these clusters can be used as seeds.

Example: Land use satellite imagery

We need to do region analysis with a set of descriptors based on intensity levels and spatial properties(such as moments or texture). Descriptors alone can yield misleading results if connectivity properties are not used in the region growing process.