watershed {EBImage} | R Documentation |
Watershed transformation and watershed based object detection.
watershed(x, tolerance=1, ext=1)
x |
An |
tolerance |
The minimum height of the object in the units of image
intensity between its highest point (seed) and the point where it
contacts another object (checked for every contact pixel). If the
height is smaller than the tolerance, the object will be combined with
one of its neighbors, which is the highest. Tolerance should be chosen
according to the range of |
ext |
Radius of the neighborhood in pixels for the detection of neighboring objects. Higher value smoothes out small objects. |
The algorithm identifies and separates objects that stand out of the background (zero). After the water fill, the source image is flipped upside down and the resulting valleys (values with higher intensities) are filled in first until another object or background is met. The deepest valleys (pixels with highest intensity) become indexed first, starting from 1.
The function bwlabel
is a simpler, faster alternative to
segment connected objects from binary images.
An Grayscale
Image
object or an array, containing the
labelled version of x
.
Oleg Sklyar, osklyar@ebi.ac.uk, 2007
x = readImage(system.file('images', 'shapes.png', package='EBImage')) x = x[110:512,1:130] if (interactive()) display(x, title='Binary') y = distmap(x) if (interactive()) display(normalize(y), title='Distance map') w = watershed(y) if (interactive()) display(normalize(w), title='Watershed')