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iblobs

features

f = iblobs(im, options) is a vector of RegionFeature objects that describe each connected region in the image im.

Options

'aspect', A set pixel aspect ratio, default 1.0
'connect', C set connectivity, 4 (default) or 8
'greyscale' compute greyscale moments 0 (default) or 1
'boundary' compute boundary (default off)
'area', [A1,A2] accept only blobs with area in the interval A1 to A2
'shape', [S1,S2] accept only blobs with shape in the interval S1 to S2
'touch', T accept only blobs that touch (1) or do not touch (0) the edge (default accept all)
'class', C accept only blobs of pixel value C (default all)

The RegionFeature object has many properties including:

uc centroid, horizontal coordinate
vc centroid, vertical coordinate
p centroid (uc, vc)
umin bounding box, minimum horizontal coordinate
umax bounding box, maximum horizontal coordinate
vmin bounding box, minimum vertical coordinate
vmax bounding box, maximum vertical coordinate
area the number of pixels
class the value of the pixels forming this region
label the label assigned to this region
children a list of indices of features that are children of this feature
edgepoint coordinate of a point on the perimeter
edge a list of edge points 2xN matrix
perimeter edge length (pixels)
touch true if region touches edge of the image
a major axis length of equivalent ellipse
b minor axis length of equivalent ellipse
theta angle of major ellipse axis to horizontal axis
shape aspect ratio b/a (always <= 1.0)
circularity 1 for a circle, less for other shapes
moments a structure containing moments of order 0 to 2

References


 

© 1990-2012 Peter Corke.