16 Silicon chip Australia’s electronics magazine siliconchip.com.au
of photos with no other criteria applied. He said that it was
hard to identify an individual “if you have no other means
but your eyes to search for the photograph among the thou-
sands in an ordinary collection”.
Early computerised systems
Modern computerised facial recognition systems have
their origins in the 1960s, with the first work carried out
by Woodrow W. Bledsoe with Helen Chan and Charles
Bisson during 1964-1966 at Panoramic Research in Palo
Alto, California.
In this work, an early digitising device known as a RAND
tablet (Fig.1) was used by a human operator to mark the
location and size of various facial landmarks of a person
on photographs.
This included the eyes, nose, mouth and hairline. These
locations were then compared with the locations stored
in a database and the closest match was used to identify
the person.
This early system was limited by the lack of computer
power and memory storage of that time but was an im-
portant first step to prove the viability of the technology.
Following Bledsoe, in the 1970s, Goldstein, Harmon and
Lesk used 21 subjective facial markers such as hair colourFig.2: a collection of faces known as the AT&T “Database of Faces”, which is a standard set used for testing and research
by people working in the facial recognition field. It consists of 10 pictures of each of 40 people.
Fig.3: the set of eigenfaces computed from the AT&T
Database of Faces shown above. In this case, principal
component analysis mapping has been computed and
the first 24 principal components (eigenfaces) are shown.
These eigenfaces can be added together in various
proportions to recreate all the original faces with little loss
of accuracy.False facial identifications and overall accuracy
Facial recognition software is not perfect, far from it, and a
bad identification can ruin someone’s life, as explained in the
article at: siliconchip.com.au/link/aane
Accurate facial recognition is very much dependent on the
quality of the original picture(s) stored in the database, includ-
ing conditions such as lighting, orientation toward the camera,
facial expression etc.
There’s also the question of just how useful it is, even when
it works. Critics have made the argument that in places like the
United Kingdom, where there is widespread surveillance and fa-
cial recognition technology in use, no (or few) criminals or ter-
rorists have been apprehended specifically due to these systems.