[Insight-developers] Re: missing ITK functions document

George Stetten stetten@pitt.edu
Tue, 27 Nov 2001 03:04:37 -0500


Hi Stephen,

I think there may be overlap with what Damion has been developing.  We
create basic shapes already which we use to calibrate shape recognition and
measurement algorithms.

George

"Stephen R. Aylward" wrote:

> Hi,
>
> Vikram has asked about the PhysicalObject classes, and so I thought I'd
> give a brief summary to the group.
>
> The goal is to devise a class hierarchy that can represent spheres,
> cubes, connected components, segmentation results, etc in a common
> framework.   In that manner, we will be able to calculate volumes,
> moments, bounding boxs, convex hulls, etc; generate masks; load and save
> scenes; and more...
>
> We are proposing a class hierarchy of "PhysicalObjects." At the base
> class, a specific type of representation (data container) of an object
> is not specified, just the basic api.   Derived types of physical
> objects will represent different types of objects and will contain data
> containers.   So, a physicalObject could be an image mask (e.g., all
> values between 10 and 100 in the image represents object A), a list of
> points, a function, a parameterize model, or a collection of other
> physicalObjects (a CSG type object).
>
> Jean-Philippe Guyon is working hard on this and is following the
> composite-pattern design in the book "Design Patterns: Elements of
> Reusable Object-Oriented Software" by Erich Gamma et al - suggested by
> Luis.
>
> A point of future discussion is what do we want at the base class level
> - what characteristics should be common to every physical object.
>
> Our first draft includes the following concepts/functions in the base
> class:
> - Position, orientation, and scale in physical space.
> - Bounding box.
> - Test if a physical point is inside a physical object.
> - Resolution of the physical object (if it is a discrete representation,
> how should we   query its points)
>
> There would be the following filters:
> * PhysicalObjectToPhysicalObject filters allow objects to be combined
> (CSG).
> * PhysicalObjectToImage filters allow objects to be drawn in images.
> * PhysicalObjectToValue filters will give you moments, etc.
>
> We've got some other ideas on where we can go with these, but we are
> going to keep it simple at first: box, sphere, tube, image-mask, and
> point-list will be the objects that we hope to provide.
>
> Comments?
>
> Thanks,
> Stephen and Jean-Philippe
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--
George Stetten, M.D., Ph.D.
Assistant Professor, Bioengineering, U. Pitt.
Research Scientist, Robotics Institute, CMU
http://www.stetten.com