Re: Chapter 4: Vision

From: Gill, Lynn (
Date: Fri Mar 07 1997 - 10:23:04 GMT

On Mon, 3 Mar 1997 11:55:51 GMT Sandra Cherry wrote:

> Having read the Devil's Advocate Box 4:3 the first half
> explaining that we are unable to encode all viewpoints of
> objects - in this case, leaves, twigs, and branches is
> understandable.
> However, the next part - describing computer graphics what
> they term L-Grammer is not so understandable!
> Is it saying that this is a computer program in which
> recognizing trees is easy. And what is, "a global
> impression built up from the repetition of microstructure?"

According to Biederman, Geons can be used to explain local features
(the microstructure) and global features ( the global impression ie.
the whole object). I think it is possible that a computer program could
be built to simulate and recognise natural objects based on repetition
of microstructure. The reason I believe this is through a very limited
understanding of fractals, (a pattern which can be described
mathematically and which can be magnified at any point to reveal a
repetition of the original pattern and so on - the global feature is
repeated in the microstructure).

Many natural objects, including trees, have been described as fractal.
If I am right, and it is based on a mathematical equation or formula,
ie. is symbolic, it should be possible to program a computer to
recognise these sorts of irregular objects. Could it also be possible
that we use geometric invariants as well as some sort of mathematical
pattern recognition system in order to recognise whole (global)
objects, like trees, from their microstucture. For example, using the
pattern of branches, twigs and leaves to recognise the type of tree? Or
am I completely off the track and in the trees!?

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