Path: utzoo!mnetor!uunet!husc6!mit-eddie!mit-amt!turk
From: turk@mit-amt.MEDIA.MIT.EDU (Matthew Turk)
Newsgroups: comp.graphics
Subject: Re: Superquadrics
Message-ID: <2243@mit-amt.MEDIA.MIT.EDU>
Date: 6 Apr 88 03:26:06 GMT
References: <8340@agate.BERKELEY.EDU> <10919@shemp.CS.UCLA.EDU>
Organization: MIT Media Lab, Cambridge, MA
Lines: 46
Summary: Supersketch

In article <10919@shemp.CS.UCLA.EDU>, trainor@lanai.cs.ucla.edu (Vulture of Light) writes:
> In article <8340@agate.BERKELEY.EDU> doug@mica.berkeley.edu (Doug Merritt) writes:
> >A few years ago I read a paper by a guy at Stanford who came up
> >with an interesting model that allowed two way transformations:
> >model => rendered image, and digitized image => model. It was
> >based on "superquadrics"; his paper did not adequately define these.
> >
> >Can someone explain "superquadrics", or give an easily accesible reference
> >that does?
> 
> Just for the other people, this is a computer vision system whose model
> of the world is comprised of superquadrics, akin to earlier systems
> that used, say, generalized cylinders.
> 
> [...]
>
> ... I suggest reading:
> 
>     Barr, A.H. ``Superquadrics and Angle-Preserving Transformations,''
>     IEEE Computer Graphics and Applications, Vol. 1, No. 1, 1981.

Alex Pentland (now at the MIT Media Lab) is the person mentioned by
Doug Merritt.  He developed a 3-D modeling system called "SuperSketch"
which uses superquadrics as its primitives.  SuperSketch allows a
user to quickly model a wide range of natural and man-made shapes
in a way that captures the intuitive "part structure" of the object.
This is the "model => rendered image" part.

The "digitized image => model" transformation is described for
range data in a paper by Pentland and Bob Bolles (see reference
below).

I believe superquadrics were invented by Peit Hein, a Danish
designer.  They are a superset of CSG modeling primitives.

 -> Barr, A. H. (above)
 -> Gardiner, M. "The superellipse: a curve that lies between
     the ellipse and the rectangle", Sci. Am., Sept 1985.
 -> Pentland, A. "Perceptual organization and the representation
     of natural form", Artificial Intelligence, May 1986.
 -> Pentland and Bolles, "Learning and recognition in natural
     environments", (don't know if this is published yet...)

Hope this helps...

	Matthew