isk-daemon: Content-based image database server

These are the basic features for the server side daemon:

• Query for images similar to one already indexed by the database, returning a similarity degree for the images on database that most resemble the target query image.
• Query for images similar to one described by its signature. A client-side widget may generate such signature from what a user sketched and submit it to the daemon.
• XML+HTTP interface for easy integration with other web and desktop or rich-client applications
• Fast indexing of images one-by-one or in batch
• Quickly remove images from database one-by-one or in batch
• Key-based security for API users
• Built-in web-based admin interface with statistics and ad-hoc maintenance commands/API testing
• Optimized image processing code implemented in C++

More upcoming features can be found on the development roadmap.