
For image segmentation, the watershed is usually, but not always, applied to
a gradient image. Since real digitized images present many regional minima in
their gradients, this typically results in an excessive number of catchment basins,
the result being called watershed oversegmentation. We now address how to
prevent this.
8.4.2 Filtering the Minima
One solution to cope with oversegmentation is to filter the image to reduce the
number of regional minima, creating fewer catchment basins. Figure 8.20 shows
the application of the classical watershed transform. The input image (a) is a small
synthetic image with three different-size Gaussian peaks. Part ...