Because world population is more than 7 billion, you may think that somewhere there is a person looking exactly like you. In fact, a lot of people believe in that and ever so often we hear about such doppelgangers meeting. However, researchers at the University of Adelaide have proved that likelihood of having such look-alike exceeds one in a trillion.
Scientists used a database analysis to figure out chances of having a doppelganger. They ran an analysis of a database, which contains measurements of almost 4,000 individuals. Initial study using 7 metric traits revealed that there were no look-alikes at all. Then scientists performed some mathematical equations with 8 facial metric traits and found that probability of identical faces in the world’s population is less than one in a trillion.
It is important to note that this research was not performed for sheer fun of having a look-alike. In fact, it proves that facial traits can be accurately used to identify a criminal – much like fingerprints and DNA. Teghan Lucas, author of the study, said: “the use of video surveillance systems for security purposes is increasing and as a result, there are more and more instances of criminals leaving their ‘faces’ at a scene of a crime. At the same time, criminals are getting smarter and are avoiding leaving DNA or fingerprint traces at a crime scene.”
There were attempts to use facial measurements in courts before, but they were denied, because there were no evidence that there could not be two identical faces. However, this study proves that facial anthropometric measurements can be effectively used to identify a person. Scientists say that there are two ways to analyse facial data for identifying people from video or photographic surveillance footage. First one is descriptive (using adjectives like ‘wide’ and ‘curved’ to describe a face), but it is not considered reliable as some traits, such as eye colour, may be subjective. Second is metric, relying on distance between specific points on the face.
Scientists used metric method as it is more reliable. This means that face on surveillance footage may be measured using anthropometric methods and compared to databases to identify a person even without having his DNA or fingerprints. Scientists are already looking into improving these techniques to effectively measure face parameters from such videos and will use these findings to help police during their investigations.