A consortium of 11 railway companies launched the one-year pilot project last month, and has set up 27 of the high-tech advertising displays in subway commuter stations around Tokyo.

"The camera can distinguish a person's sex and approximate age, even if the person only walks by in front of the display, at least if he or she looks at the screen for a second," said a spokesman for the project.

If data for different locations is analysed, companies can provide interactive advertisements "which meet the interest of people who use the station at a certain time," the project said in a statement.