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.:. LIBPUZZLE - PHP EXTENSION .:.
http://libpuzzle.pureftpd.org
------------------------ PHP EXTENSION ------------------------
The Puzzle library can also be used through PHP, using a native extension.
Prerequisites are the PHP headers, libtool, autoconf and automake.
Here are the basic steps in order to install the extension:
(on OpenBSD: export AUTOMAKE_VERSION=1.9 ; export AUTOCONF_VERSION=2.61)
cd php/libpuzzle
phpize
./configure --with-libpuzzle
make clean
make
make install
If libpuzzle is installed in a non-standard location, use:
./configure --with-libpuzzle=/base/directory/for/libpuzzle
Then edit your php.ini file and add:
extension=libpuzzle.so
------------------------ USAGE ------------------------
The PHP extension provides bindings for the following tuning functions:
- puzzle_set_max_width()
- puzzle_set_max_height()
- puzzle_set_lambdas()
- puzzle_set_noise_cutoff()
- puzzle_set_p_ratio()
- puzzle_set_contrast_barrier_for_cropping()
- puzzle_set_max_cropping_ratio()
- puzzle_set_autocrop()
Have a look at the puzzle_set man page for more info about those.
Getting the signature of a picture is as simple as:
$signature = puzzle_fill_cvec_from_file($filename);
In order to compute the similarity between two pictures using their
signatures, use:
$d = puzzle_vector_normalized_distance($signature1, $signature2);
The result is between 0.0 and 1.0, with 0.6 being a good threshold to detect
visually similar pictures.
The PUZZLE_CVEC_SIMILARITY_THRESHOLD, PUZZLE_CVEC_SIMILARITY_HIGH_THRESHOLD,
PUZZLE_CVEC_SIMILARITY_LOW_THRESHOLD and PUZZLE_CVEC_SIMILARITY_LOWER_THRESHOLD
constants can also be used to get common thresholds :
if ($d < PUZZLE_CVEC_SIMILARITY_THRESHOLD) {
echo "Pictures look similar\n";
}
Before storing a signature into a database, you can compress it in order to
save some storage space:
$compressed_signature = puzzle_compress_cvec($signature);
Before use, those compressed signatures must be uncompressed with:
$signature = puzzle_uncompress_cvec($compressed_signature);
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