A pair of glasses dubbed a “privacy visor” has been developed to make the user invisible to hidden cameras using facial-recognition software.

The prototype spectacles have been designed by scientists at Tokyo’s National Institute of Informatics.

The glasses are equipped with a near-infrared light source, which confuses the software without affecting vision.

Law enforcers, shops and social networks are increasingly using facial-recognition software.

Prof. Isao Echizen said: “As a result of developments in facial recognition technology in Google images, Facebook et cetera and the popularization of portable terminals that append photos with photographic information [geotags]… essential measures for preventing the invasion of privacy caused by photographs taken in secret and unintentional capture in camera images is now required.”

The near-infrared light “appends noise to photographed images without affecting human visibility,” he said.

The glasses dubbed privacy visor has been developed to make the user invisible to hidden cameras using facial-recognition software

Prof. Isao Echizen said the glasses, which connect to a pocket power supply, would be reasonably priced, but there are some simpler alternatives.

Heavy make-up or a mask will also work, as will tilting your head at a 15-degree angle, which fools the software into thinking you do not have a face, according to an online guide produced by hacktivist group Anonymous.

In September, following a review by Ireland’s data protection commissioner, Facebook suspended its facial-recognition tool that suggested when users in Europe could be tagged in photographs.

In November, it emerged some shop mannequins were collecting data on shoppers using facial-recognition software.

The EyeSee mannequin logs the age, gender and race of passers-by through a camera hidden behind one eye.