Face Recognition is definitely one of the most popular computer vision problems. Thanks to its popularity it has been well studied over the last 50 years. The first intents to explore face recognition were made in the 60′s however it was until the 90′s when Turk and Pentland implemented the “Eigenfaces” algorithm, that this field showed some really exciting and useful results.
Face recognition is recently getting more and more attention and we can anticipate bright future of this field.
Security was historically and will stay in the future the main application of face recognition in practice. Here face recognition can help with both: identification and authentication. Good example is the Frankfurt airport security system which uses face recognition to automatize passenger control. Another application can be the security analysis of videos purchased by external city cameras systems. Potential suspects can get identified before committing crime. Take a look at the integration of face recognition to London Borough of Newham, already in 1998.
Face recognition can be also used to speedup the identification of persons. We can image a systems which would recognize the client as soon as he walks into branch store (bank, assurance), and the front-office worker can than welcome the client by has name and prepare his folder before he actually gets to the counter.
Advertising companies are working on ad-boards which would adapt their content to the persons passing by. After analyzing the persons face, commercials would adapt to the gender, age, or even personal style. This usage however, might not conform to privacy laws. Private companies do not have rights to film persons in public places (of course, depending on the country.
Not to forgot, that Google and Facebook had both implemented algorithms to identify users in the huge database of photos which they maintain as part of their social network services. Third party services, such as Face.com offer Image base searching, which allow you search for example for picture which contain together your best friends.