New research suggests that face recognition security on smartphones can be significantly improved if users store an "average" photo of themselves.

Researchers at the University of York found that combining different pictures of the user, rather than a single "target" image, leads to much better recognition across all kinds of daily settings.

For the study, researchers examined the performance of the "face unlock" system on Samsung Galaxy phones.

They found that the system was generally very good at rejecting imposters, but that it often failed to recognize the genuine owner too. However, performance could be greatly improved, often to perfect levels, if users stored an 'average' of their own photos -- formed by morphing together several different photos of the user.

"We chose to study the Samsung Galaxy because it is a very popular phone which comes with working face recognition technology," Dr. David Robertson, who led the study, said in a statement. "However, we expect this technique to work across a wide range of phones and other automated recognition devices. It is very interesting that performance can be so much improved by copying a simple trick performed by the brain."

The idea for this technique apparently came from studies of human face recognition, according to researchers.

"It is understood that the brain forms abstract representations of the faces it knows, and that people are very good at recognizing their family and friends over a range of conditions," according to  the study.

 If it is possible to copy these representations, then automatic face recognition can improve. Using 'average' images is a simple way to do this.

The findings are published in the journal PLOS ONE.