isk-daemon: Content-based image database server

Visual image similarity considers the basic shape and color information of the query when looking through the database for potential matches.

isk-daemon uses wavelet algorithms, metric and query ideas based on the paper “Fast Multiresolution Image Querying” by Charles E. Jacobs, Adam Finkelstein and David H. Salesin.

The core image similarity algorithm uses a multi-resolution wavelet decomposition approach for solving the problem of determining the top-k similar images to a target among a pre-indexed database. Among some of it’s advantages, this approach allows queries to be specified at any resolution (possibly different from that of the target); moreover, the running time and storage of our method are independent of the resolutions of the database images.

The signature information for each image computed by isk-daemon can be extracted from a wavelet-compressed version of the image directly, allowing the signature database to be created conveniently from a set of compressed (low-resolution) images.

Why using wavelets: Wavelet decompositions allow for very good image approximation with just a few coefficients. As such, this property has been exploited for lossy image compression. Typically, in these schemes, just the wavelet coefficients with the largest magnitude are used. Wavelet decompositions can be used to extract and encode edge information. When doing query-by-sketches, edges from user drawn strokes are likely to be among the key features. The coefficients of a wavelet decomposition provide information that is independent of the original image resolution. Thus, a wavelet-based scheme allows the resolutions of the query and the target to be effectively decoupled. Wavelet decompositions are fast and easy to compute, requiring linear time in the size of the image and very little code. See more scalability details.

Version: 0.6.2 (released 30/Aug/2007)

Please read the install and usage instructions.

Download links

• Zip files are for Windows x86 32-bits
• Gz files are for Debian/Gentoo Linux x86 32-bits

Changelog

• All trial restrictions removed.
• Released as opensource (GPL).
• File packages now hosted on SourceForge.net
• SF.net bug tracker is now used

Known issues

1. On Windows, image filenames with extended characters won’t get imported
2. saveAllDbs() and loadAllDbs() returns 1 on success instead of db count as mentioned on API docs
3. saveDbAs() is not remembering the supplied filename, so further calls to saveDb() will save to a file named “not yet saved” instead of the previous one.
4. mostPopularKeywords() API call doesn’t work as expected

Version 0.6 - Released 21/July/2007

1. Support for keyword management:
   1. Keywords could be used to identify users so isk-daemon can keep track of which images belongs to which user. This way you can do keyword-related queries on isk-daemon in order to query for similar images inside a user’s collection.
   2. Keywords can be interpreted as being just set identifiers, so in a sense this allows your application to tell isk-daemon which sets an image belongs to.
   3. These ids may be generated by hashing text-based keywords from an existing keyword oriented image management system.
   4. Only keyword ids (integers) are stored on isk-daemon
2. More example Java, PHP and Python client libraries.
3. Improved web admin interface.
4. Internal support for multiple image database spaces so image databases can be segmented into partitions (also called database spaces) and persisted to different data files or a single file for all database spaces.
5. Trial and Full versions are now delivered on the same build. Full version users must enter a valid license key on the settings.py file. Existing full version users will receive a valid key.
6. Many bug fixes.
7. Indexed image can be associated with keywords and new search methods are available for using keywords to narrow down the visual similarity search space.
8. Memory leaks fixed.

Version 0.6.1 - Released 7/Aug/2007

1. Windows version is now linked against the latest ImageMagick release.

Version 0.6.2 - Released 30/Aug/2007

1. All trial restrictions removed.
2. Released as opensource (GPL).
3. File packages now hosted on SourceForge.net
4. SF.net bug tracker is now used