--- name: "findimagedupes" section: "1" platform: "linux" package: "findimagedupes" version: "2.11-2" release: "Debian 5.0 (Lenny)" platforms: ["linux"] url: "https://new.carta.tech/findimagedupes" --- # findimagedupes(1) Finds visually similar or duplicate images ## NAME findimagedupes - Finds visually similar or duplicate images ## SYNOPSIS findimagedupes \[option ...\] \[--\] \[ - \| \[file ...\] \] ``` Options: -f, --fingerprints=FILE -c, --collection=FILE --merge=FILE -p, --program=PROGRAM --prune -s, --script=FILE -a, --add -r, --rescan -q, --quiet -n, --no-compare -v, --verbosity=LIST -d, --debug=OPTS -t, --threshold=AMOUNT -h, --help -0, --null --man ``` With no options, compares the specified files and does not use nor update any fingerprint database. Directories of images may be specified instead of individual files; Sub-directories are NOT searched recursively. ## INSTALLATION If you use linux, your distribution may include a prepackaged version. For example, Debian and Ubuntu do. Otherwise, at a minimum you'll need Perl with the modules listed at the top of the findimagedupes script. Also the GraphicksMagick package. You may need to change Inline's `"DIRECTORY"` to point somewhere else. Read the Inline module documentation for details. ## OPTIONS - **-0**, **--null** If a file `"-"` is given, a list of files is read from stdin. Without **-0**, the list is specified one file per line, such as produced by [*find*(1)](/find/1.md) with its `"-print"` option. With **-0**, the list is expected to be null-delimited, such as produced by [*find*(1)](/find/1.md) with its `"-print0"` option. - **-a**, **--add** Only look for duplicates of files specified on the commandline. Matches are also sought in any fingerprint databases specified. - **-c**, **--collection**=*FILE* **NOT IMPLEMENTED** (does anyone use this option?) Create GQView collection *FILE*.gqv of duplicates. - **-d**, **--debug**=*OPTS* Enable debugging output. Options *OPTS* are subject to change. See the program source for details. - **-f**, **--fingerprints**=*FILE* Use *FILE* as fingerprint database. May be abbreviated as **--fp** or **--db**. This option may be given multiple times when **--merge** is used. (Note: *FILE* could contain commas, so multiple databases may not be specified as a single comma-delimited list.) - **-h**, **--help** Print usage and option sections of this manual. - **--man** Display the full documentation, using default pager. - **--merge**=*FILE* Takes any databases specified with **--fingerprints** and merges them into a new database called *FILE*. Conflicting fingerprints for an image will cause one of two actions to occur: - 1\. If the image does not exist, then the entry is elided. - 2\. If the image does exist, then the old information is ignored and a new fingerprint is generated from scratch. By default, image existence is not checked unless there is a conflict. To force removal of defunct data, use **--prune** as well. A list of image files is not required if this option is used. However, if a list is provided, fingerprint data for the files will be copied or (re)generated as appropriate. When **--merge** is used, the original fingerprint databases are not modified, even if **--prune** is used. See also: **--rescan** - **-n**, **--no-compare** Don't look for duplicates. - **-p**, **--program**=*PROGRAM* Launch *PROGRAM* (in foreground) to view each set of dupes. See also: **--script**. - **--prune** Remove fingerprint data for images that do not exist any more. Has no effect unless **--fingerprints** or **--merge** is also used. Databases specified by **--fingerprints** are only modified if **--merge** is not used. - **-q**, **--quiet** This option may be given multiple times. Usually, progress, warning and error messages are printed on stderr. If this option is given, warnings are not displayed. If it is given twice or more, errors are not displayed either. Information requested with **--verbosity** is still displayed. - **-r**, **--rescan** (Re)generate all fingerprints, not just any that are unknown. If used with **--add**, only the fingerprints of files specified on the commandline are (re)generated. Implies **--prune**. - **-s**, **--script**=*FILE* When used with **--program**, *PROGRAM* is not launched immediately. Instead [*sh*(1)](/sh/1.md)-style commands are saved to *FILE*. This script may be edited (if desired) and then executed manually. When used without **--program**, a skeletal shell function `"VIEW"` is generated, which simply [*echo*(1)](/echo/1.md)s its arguments. To display to terminal (or feed into a pipe), use `"-"` as *FILE*. - **-t**, **--threshold**=*AMOUNT* Use *AMOUNT* as threshold of similarity. Append `"%"` to give a percentage or `"b"` for bits. For backwards compatibility, a number with no unit is treated as a percentage. Percentage is the minimum required for a match; bits is the maximum that may differ: bits=floor(2.56(100-percent)) A fractional part may be given but it is only accurate to 100/256 (0.390625) for percentage and it is meaningless for `"bits"`. Default is `"90%"` (`"25b"`) if not specified. - **-v**, **--verbosity**=*LIST* Enable display of informational messages to stdout, where *LIST* is a comma-delimited list of: - **md5** Display the checksum for each file, as per [*md5sum*(1)](/md5sum/1.md). - **fingerprint** \| **fp** Display the base64-encoded fingerprint of each file. Alternatively, **--verbosity** may be given multiple times, and accumulates. Note that this may not be sensible. For example, to be useful, **md5** output probably should not be merged with **fingerprint** data. ## DESCRIPTION **findimagedupes** compares a list of files for visual similarity. - To calculate an image fingerprint: ``` 1) Read image. 2) Resample to 160x160 to standardize size. 3) Grayscale by reducing saturation. 4) Blur a lot to get rid of noise. 5) Normalize to spread out intensity as much as possible. 6) Equalize to make image as contrasty as possible. 7) Resample again down to 16x16. 8) Reduce to 1bpp. 9) The fingerprint is this raw image data. ``` - To compare two images for similarity: ``` 1) Take fingerprint pairs and xor them. 2) Compute the percentage of 1 bits in the result. 3) If percentage exceeds threshold, declare files to be similar. ``` ## RETURN VALUE - 0 Success. - 1 Usage information was requested (**--help** or **--man**), or there were warnings. - 2 Invalid options or arguments were provided. - 3 Runtime error. Any other return values indicate an internal error of some sort. ## DIAGNOSTICS To be written. ## EXAMPLES To be written. ## FILES To be written. ## BUGS There is a memory leak somewhere. Killing the programme may corrupt the fingerprint database(s). Changing version of GraphicsMagick invalidates fingerprint databases. ## NOTES Directory recursion is deliberately not implemented: Composing a file-list and using it with `"-"` is a more flexible approach. Repetitions are culled before comparisons take place, so a commandline like `"findimagedupes a.jpg a.jpg"` will not produce a match. The program needs a lot of memory. Probably not an issue, unless your machine has less than 128MB of free RAM and you try to compare more than a hundred-thousand files at once (and the program will run quite slowly with that many files anyway---about eight hours initially to generate fingerprints and another ten minutes to do the actual comparing). ## SEE ALSO [*find*(1)](/find/1.md), [*md5sum*(1)](/md5sum/1.md) **gqview** - A simple image viewer using GTK+ ## AUTHOR Jonathan H N Chin \ ## COPYRIGHT AND LICENSE ``` Copyright 2006 by Jonathan H N Chin . This program is free software; you may redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA ``` ## HISTORY This code has been written from scratch. However it owes its existence to **findimagedupes** by Rob Kudla and uses the same duplicate-detection algorithm.