Banana Screen is an interesting little application that allows you to lock and unlock your computer using face recognition. The application is simple to setup and use and makes unlocking your computer faster than having to type a password each time you sit down.
The program is currently in beta so expect improvements in the coming months. At the moment the balance between ease of use and accuracy is not quite right. The application allows you to register a number of different face models which allow recognition under a variety of lighting conditions and face poses, however, I’ve found that if you over train the model the systems tends to produce far too many false positives. If the model is under-trained then lighting conditions at different times of the day tend to produce too many false negatives. Furthermore the lack of control over which input images are used as a part of the recognition model means that in order to correct the under-training or over-training issues the whole face model must be deleted and training started from scratch. The forums suggest that people at Banana Screen are working on these problems though so whilst at the moment it is not secure enough to replace traditional password entry in environments where security is of particular importance it is an interesting toy for the home PC user. Hopefully the transition for toy to security application will come as the program matures.
At the moment Banana Screen can only handle screen locking rather than true windows login, this is probably a prudent move whilst the program is in beta, as they are trying to avoid deep windows integration during the beta stage. This seems to be a wise move since a similar program for face recognition based login for windows systems, called FaceCode, makes a horrible mess of the login process, is difficult to uninstall and is an advertisement for the Banana Screen approach. I highly recommend trying out this software as I believe when it matures it will be a high quality product.