[Fwd: [Insight-developers] proposal for ROI class]

[Stephen R. Aylward]

Hi,

I won't be able to make today's tcon (or next week).   I should be able
to attend consistently after June 1.

About the physicalObject base class - it is abstract.   An internal
representation type is not specified.   So, each object type can have
its own representation (implicit, explicit, list of points, centers and
radius for tubes, etc).   Maybe it should be extended to include an
iterator over the points in the object?

Anyway, just another option.
 
s
 
> Lydia Ng wrote:
> >
> > This is a follow up to last week's tcon
> > discussion on ROI's (region of interest).
> >
> > In registration there is often a need to restrict
> > the registration process to some region of interest
> > e.g. inside the CT circle, inside an organ etc ...
> >
> > I am putting together some ideas on how we should
> > represent ROI in ITK which we can discuss in this
> > week's tcon.
> >
> > What access modes do we want to support?
> > ==========================================
> > The ones I need for my registration algorithms are:
> > (1) iterate through all points in the ROI
> > (2) randomly sample points from an ROI (for mutual information)
> >
> > Representation options:
> > =======================
> > (A) Binary mask:
> >
> > Mode (1) access can be achieve by a for loop and checking if
> > pixel is in ROI.
> > Mode (2) access can be achieve by uniformly sampling the whole
> > image, if pixel is not in ROI - choose another one.
> >
> > Requires the char image the same size as the input images.
> >
> > (B) PointSet containing all points in ROI:
> >
> > Can easily support both mode of access.
> > But can more memory expensive than (A) if ROI covers
> > a large portion of the image.
> >
> > (C) PhysicalObject:
> >
> > The UNC folks are working on a PhysicalObject base class
> > with four virtual member functions:
> >
> > > 1) specify a physical transformation to position the object in space
> > > 2) bool for: is point x within the object
> > > 3) generate a binary instance of the object in an image
> > > 4) quantify the quality of fit of the object to an image
> >
> > I am not sure of the underlying representation, perhaps Stephen
> > can talk about it a bit more at the tcon.
> >
> > ----------------------------
> > What do people prefer? Are there other contenders?
> >
> > Lydia
> >
> > _______________________________________________
> > Insight-developers mailing list
> > Insight-developers@public.kitware.com
> > http://public.kitware.com/mailman/listinfo/insight-developers
> 
> --
> =======================================================================
> Stephen R. Aylward, Ph.D.                       www.cs.unc.edu/~aylward
> Research Assistant Professor of Radiology               aylward@unc.edu
> Adjunct Assistant Professor of Computer Science           (919)966-9695

-- 
=======================================================================
Stephen R. Aylward, Ph.D.			www.cs.unc.edu/~aylward
Research Assistant Professor of Radiology		aylward@unc.edu
Adjunct Assistant Professor of Computer Science		  (919)966-9695