Jordanian experts claim that new techniques allow them to identify masked jihadists by their V for victory signs.
With jihadists frequently masked in propaganda films, experts are often forced to rely on imperfect methods such as voice analysis for identification.
However, Ahmad Hassanat and other experts at the Mu'tah University in Jordan claim that the V signs used by fighters give away their identity.
"Identifying a person using a small part of the hand is a challenging task and has, to the best of our knowledge, never been investigated," says the team in the study.
The team began by asking 50 men and women of varying ages to make a V sign and photographed it several times against a black background with an eight-megapixel camera.
They 'connected the dots' between the end points of the two fingers, the lowest point in the valley between them, and the two points in the palm of the hand. They then used two-thirds of the images to train a machine-learning algorithm to recognise different V signs, the remaining images to test its efficacy.
The techniques allow them to identify people in the dataset to 90 per cent accuracy, the team says.
"There is a great potential for this approach to be used for the purpose of identifying terrorists, if the victory sign were the only identifying evidence," they say.
The team will seek to refine the results to avoid the chances of misidentification, performing the test on a larger number of test subjects, and building in factors such as finger length.