A technical article on identifying images

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misc A technical article on identifying images

The previous item asked for help identifying the subjects shown in pictures - in this particular case some cinderella stamps. In general that's a hard problem, so I thought it's worth writing about various approaches to the problem itself.

The approaches


Simply asking is an example of croudsourcing - applying many eyes and brains to the task in the hope that someone out there can provide the answer. Humans experts are ideal for this task!

TinEye reverse search engine

There are however a number of computer helpers we can apply to the task, and the TinEye reverse image search is the first of these. In their words, "You can submit an image to TinEye to find out where it came from, how it is being used, if modified versions of the image exist, or to find higher resolution versions." This is great because we can use it directly on our own image files. Of course, the match is dependent on the image being in their database, which they currently claim is 1,256,651,249 images.

Google Goggles

As mobile phones become more and more powerful, the combination of computer power, a camera, and internet connectivity has lead to some very interesting possibilities. Google Goggles is a mobile phone application that allows you to "use pictures to search the web." You need an Android powered phone to use this at the moment, and the general idea is that you take a picture of something using the phone camera, and a that is used to do a Google search. The end result is doing the search, but of course along the way the system has to try to identify what you were taking a picture of.

We are slightly fortunate in this particular case because the subject matter is constrained - all the stamps are although very poor reproductions, obviously taken from paintings, and "artwork" is one of the categories of images that Google Googles particularly specializes in.

The major downside to this is that we can't use this to directly recognise our images - we have to (first locate an Android phone and then) display the image on a computer screen and use the phone camera to rephotograph it.


PlinkArt is another Android mobile phone application, that also allows you to take a picture of some artwork with your phone camera, and to identify it and find out about it.

Creative guesswork

There is actually a further constraint to our particular problem - the producers of these cinderella stamps probably simply found their images off the internet. So we can do the same - plug "windmill painting" into an appropriate image search engine, and look for the images amongst the results.

How did each approach do?

See also:Benin windmill stamps (cinderellas) (9/1/10)
See also:Just one windmill painting stamp we can't identify (28/6/11)
Item: #748, Posted: 10/1/10.

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