[comp.ai.neural-nets] Artificial Vision: Recognizing Overlapped Images

loren@tristan.llnl.gov (Loren Petrich) (07/14/90)

	I'm planning a project to use a Neural Net or something
similar to recognize overlapped star images and the like on an
photographic or CCD image.

	I plan a number of things to simplify this task. The first is
to have some way of "pointing out" images. This would be done by
taking all the region of enhanced brightness around each peak. This
will result in an image with much fewer pixels (one hopes!) and should
be much more convenient for a pattern recognizer.

	I am planning further pre-processing of an image: one would be
to rotate it until it has a specified orientation. This would be with
the help of a moment expansion; the long axis would be rotated around
to some specified orientation.

	And I am also planning some Principal Components Analysis.
That would be to solve the eigenproblem

	imsq.mask = eigenvalue*mask

	where

	imsq = sum(parms) image(parms)*image(parms)

	One would select out the masks with the highest eigenvalues;
these would select out the "components" of the image with the highest
variation, and thus considerably lessen the load on the Neural Net.

	Has anyone else tried tricks like the ones I describe (the PCA
trick is NOT original with me, I should say)?

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