Asirra
Asirra was a research project by Microsoft that, analogous to CAPTCHAs , should serve to decide whether the other person is a human or a machine ( bot ). The acronym stands for Animal Species Image Recognition for Restricting Access . In contrast to a CAPTCHA, no combinations of letters and numbers have to be entered, but images of cats surrounded by dogs have to be recognized. A person can do this without problems, for programs this can probably only be done with a very high computing effort. Asirra can already be used productively. There are also corresponding extensions for known systems such as vBulletin or MediaWiki . For some time now, a note has been displayed above the selection box that the project will be discontinued on October 6, 2014.
Explanation
In order to protect web applications such as discussion forums , a selection of images of dogs and cats is shown to the visitor when using Asirra. The visitor has to recognize and mark the pictures of cats. Ordinary CAPTCHA are often very illegible and in some cases already recognizable by computers. Asirra is based on a database with over 3 million images and can therefore only be removed from a computer with very high computing effort. The solution developed by the Microsoft research department is based on JavaScript and a Microsoft web service that performs the analysis.