Region Growing
Algorithms that segment an image by propagating some seeds.
- MarkerBasedWatershed2d: Performs a fast determination of the watershed lines in a two-dimensional grayscale image from a predefined set of markers.
- MarkerBasedWatershed3d: Performs a fast determination of the watershed lines in a three-dimensional grayscale image from a predefined set of markers.
- MarkerBasedWatershedByBlock: Performs a fast determination of the watershed lines in a grayscale image from a predefined set of markers in a low memory consumption mode.
- MarkerBasedWatershedBasinsByBlock: Performs a fast determination of the catchment basins in a grayscale image from a predefined set of markers in a low memory consumption mode.
- ExpandLabelsOnBackground: Performs an iterative dilation of a label image, until the entire background is filled by labels.
- FloodFillThreshold2d: Transforms a grayscale two-dimensional image into a binary image by performing a region growing from a seed.
- FloodFillThreshold3d: Transforms a grayscale three-dimensional image into a binary image by performing a region growing from a seed.
- Waterpixel: Computes an image of atomic regions that share common characteristics.
This group contains segmentation algorithms based on seed propagation.
Figure 1. The watershed principle
Figure 2. Example of how the result depends on the choice of markers
References
Introduction to Watershed
The principle of the watershed algorithm is called immersion, and it is based on a simulation of the rise of water from a set of markers. The level $p$ is flooded at a uniform speed from the fronts coming from level $p-1$ and the local minima appear at level $p$. A point of the watershed appears when two distinct fronts join.Figure 1. The watershed principle
Figure 2. Example of how the result depends on the choice of markers
References
- L. Vincent and P. Soille. "Watersheds in Digital Spaces: An Efficient Algorithm Based on Immersion Simulations". IEEE Transactions on Pattern Analysis and Machine Intelligence archive , Vol. 13, Issue 6, pp. 583-598, June 1991.
- S. Beucher and F. Meyer. "The morphological approach to segmentation: the watershed transformation". In E. Dougherty, editor, Mathematical morphology in image processing, chapter 12, pp. 433-481. Marcel Dekker, 1993.