hullFeatures {EBImage} | R Documentation |
Hull features are a set of numeric descriptors of the hull of an object. These include coordinates, perimeter, size, acircularity etc.
## S4 method for signature 'IndexedImage': hullFeatures(x, ...)
x |
An object of IndexedImage . |
... |
Reserved. |
The extracted features are (names carry an h.
prefix to indicate hull
features): x,y
- coordinates of the geometric center, s
- size (area),
p
- perimeter, pdm
- mean distance to perimeter (from the center),
pdsd
- standard deviation of the distance to perimeter, effr
-
effective radius (is the radius of a circle with the same area), acirc
-
acircularity (fraction of pixels outside of the circle with r=reff
),
sf
- shape factor (per / ( 2 * sqrt(Pi * s))
), edge
-
number of pixels at the edge of the image, theta
- hull's rotation
angle (calculated without taking intensity values into account), s2maj
-
2 times semi major (square root of the larger eigenvalue of the
moments
covariance matrix) - correlates with the distance from
the center to the edge along the major axis, s2min
- same but for the
smaller eigenvalue (minor axis), ecc
- eccentricity
(sqrt(eig1-eig2)/smaj
), I1, I2
- first and second rotation invariant
moments of the hull (as in moments
).
For a single frame, a matrix of descriptors with objects in rows and features in columns. For image stacks, a list of such matrices.
Oleg Sklyar, osklyar@ebi.ac.uk, 2007
IndexedImage, watershed, getFeatures,
edgeFeatures, moments
## see example(getFeatures)