Welcome in 2006 2011!
Back to the playground!

retrievr is an experimental service which lets you search and explore in a selection of Flickr images by drawing a rough sketch.

Currently the index contains many of Flickr's most interesting images. If you'd like to have your images (or the images for a specific tag) added, please let me know. A submission interface is planned!

Does it actually work?

Yes! That is, it depends. (Mainly on your expectations!)

In my experience, the results are usually fairly good, sometimes even stunning - considering the artistic sophistication most of us are able to come up with (gallery forthcoming); and in the cases they're not so stellar, they are at least entertaining ;-) But clearly, the approach has its limits.

One thing to keep in mind is that retrievr doesn't do object/face/text recognition of any kind, so if you're drawing an outline sketch of a chair, it almost certainly won't get you one back (except your index only contains images of chairs). The same holds for corporate logos, icons &c.

It helps to think of it as matching the most pronounced shapes and slabs of colors.

Another thing to know is that there's currently no way to specify the aspect ratio, so you have to rescale the image in your head (things that are close to the borders of the image you're thinking of should be close to the borders of your sketches), but that's really more of a missing feature of the drawing flashlet than an inherent problem. Sometimes it also helps to remove detail instead of adding it.

Personally, I see retrievr more as an "exploration" tool than as a "search" tool, and it seems to work very well for that.


retrievr is based on research conducted by Chuck Jacobs, Adam Finkelstein and David Salesin at the University of Washington: Fast Multiresolution Image Querying (1995).1

I first came across the algorithm when someone (I think Edd Dumbill) linked to imgSeek a couple of years back; imgSeek is a standalone image management application that incorporates that algorithm as well.

retrievr is a new implementation in pure Python (and a host of great libraries: Fredrik Lundh's PIL and aggdraw as well as numarray). The frontend has been created using Helma and Macromedia Flash.

And now?

We'll continue to work on enhancing retrievr as well as a host of other applications. Stay tuned and watch this space!


My thanks go to all the great people who share such amazing photos on Flickr (and thereby make creating a service like that [and so many others] worthwhile in the first place), Jacobs, Finkelstein and Salesin for coming up with the scheme, the folks at Flickr/Yahoo!, who have created and continue to run and evolve a fantastic service (special thanks for being so generous and putting no up-front limits on their API!), the developers of the fine free software packages mentioned above, earl for mental and proofreading support, and last but most certainly not least System One for making it possible to work on services like that and following an open development process.

Christian Langreiter, 2006-01-02

1One of my all-time favourite papers; recommended reading for anyone with even a passing interest in image retrieval.