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fgrain

$ \bigcirc$Name


fgrain Grain filter of an image




$ \bigcirc$Command Synopsis


fgrain [-a min_area] image_in image_out



-a min_area : Min area of grains we keep (default:20)

image_in : Input fimage

image_out : Output fimage




$ \bigcirc$Function Summary


void fgrain (pMinArea , pFloatImageInput , pFloatImageOutput )

int *pMinArea ;

Fimage pFloatImageInput , pFloatImageOutput ;




$ \bigcirc$Description


This module applies the so-called grain filter to an image [MM98] . This is a filter close to the extrema killer of Vincent [Vin93], with one major difference: it is self-dual, meaning that it commutes with the negative operator,

T(- u) = - T(u).

Its other properties are mainly that it is morphological, affine invariant, idempotent, it does not destroy T-junctions and does not move level lines. It is a semi-local operator, but not local (no associated PDE). As it is a morphological filter, it can be written as an inf-sup, and the sup-inf version is the same (it is simultaneously an opening and a closing). This filter removes the shapes of an image (see module flst) that have a too small area. So this requires the datum of a threshold of area, this area could be interpreted as the scale to define a scale-space [MG99][MG00]. It is a good example of a very simple use of the modules flst and flst_recontruct.




$ \bigcirc$See Also


flst, flst_reconstruct.




$ \bigcirc$Version 1.1


Last Modification date : Thu Nov 29 20:23:56 2001


$ \bigcirc$Author


Pascal Monasse, Frederic Guichard






next up previous contents index
Next: forder Up: Reference Previous: fconvol   Contents   Index
mw 2004-05-05