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Flickr Captcha

A captcha is a way to tell a computer from a real person, this is done to verify a real person to, for example, add a comment to a blog. The test is usually some kind that is hard to do in software but simple for us humans to do, a common example is reading text from an image.

Another test that is hard for computers but easy for us is image recognition - this is where flickr comes in. By selecting certain random images from flickrs huge base we can create a test that we can use to authorise a person.

It's quite a straight forward process. We just need two different sets of photos, mix them up and allow a user to choose one of the sets. In flickr we can get a selection of photos by tag name. We connect to flickr and request a number of photos with two different tags - the tags should be contained in two unassociated categories: "tiger" and "lion" would not be a good choice, but something like "banana" and "zebra", or "spaghetti" and "clouds" are better.

Here's an example using "giraffe" and "moon". There is currently a total of 268166 and 1364515 respectively.

october (2)Amazing Fantasy planetscapeRothschild Giraffe
Rothschild GiraffeRothschild Giraffe#340
MOONRothschild GiraffeSaber Dress Code
Rothschild Giraffe

giraffe?



Select the photos tagged with "giraffe".

This shows how the basic system would work. Obviously you'd have to have a back end system to do the checking but this should give you a good idea of how it would work.

You can try some other words by typing in the boxes below. You can try a group of words by seperating them with commas.

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