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Re: [help-GIFT] Fwd: Big database on GIFT. gift-generate-inverted-file e

From: David Squire
Subject: Re: [help-GIFT] Fwd: Big database on GIFT. gift-generate-inverted-file error.
Date: Wed, 25 Feb 2004 19:25:39 +1100
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.5) Gecko/20031007

Wolfgang Müller wrote:

1. imagemagick convert to generated thumbnail and ppm files.
2. gift-extract-features and gift-write-feature-descs to get features
and creat .fts files.
3. gift-generate-inverted-file to generate InvertedFile.db.

Yes, and things do not need to remain that way. In fact, David McG. Squire (founder of the Viper project) who wrote the feature extraction had his "home-made" PPM routines and used them for feature extraction. I did not really want to touch his code, so I wrote the perl wrapper around that which uses image magick convert. In fact, much of the time the feature extraction takes is due to startup of convert and startup of gift-feature-extraction. Both of these programs have to be started for each image. The're both C, so dynamic linking is fast compared to c++, but it still takes non-negligible time of the whole feature extraction process.

If you're interested in speed, I would suggest you to extend gift-feature-extraction such that you combine with the libmagick library. I had some stuff doing that (among other things) for my thesis, but I never released it due to feature creep and due to libhell (I had so many pluggable components that things became a maintenance nightmare. Nice to work with at home, but you needed real practice to install it and due to my new job I did not have the time to get it ready for other people.)
Yep. It would certainly make an enormous amount of sense to link with libmagick. This is an example of a quick and dirty prototype making it into the product because it worked "well enough". I should use it in my software engineering class :)

On the topic of features, I am fishing for an honours student to work on this this year. I am thinking of a complete redesign, where the fundamental element is a segment rather than an image.



PS. We might even get into the DAG stuff, Wolfgang...

Dr. David McG. Squire, Postgraduate Research Coordinator (Caulfield),
Computer Science and Software Engineering, Monash University, Australia

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