On Wed, Jan 21, 2009 at 08:58:25AM +0000, A Navaei wrote: > Hi, > > I am trying to use Dolfin for solving some standard image processing > optimisation problems. Creating the corresponding equations requires > incorporation of image data as dense matrices into the problem, here > is an example: > > http://users.fmrib.ox.ac.uk/~steve/review/review/node3.html > > where Eq (4) is of interest, where the unknowns are (u, v) and I is > the image pixel values. > > A good start is to initialise the pixel values into a simplicial > triangulated mesh. Which Dolfin classes should be used in order to > perform this? > > > -Ali
I imagine you could define a Function I (the image brightness function) as either a piecewise linear function with one value at each vertex (corresponding to a pixel) or a piecewise constant function with one value at each pair of triangles (together corresponding to a pixel). So you need to overload the eval() in a user-defined function I to return the correct values by some kind of table look-up (finding the pixel values). -- Anders
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