Scientists have developed a smart suitcase that warns blind users of impending collisions and a smartphone app that can help people with visual disabilities to navigate airport terminals safely and independently.

Developed by Carnegie Mellon University (CMU) in the US and IBM, the navigation app called NavCog provides turn-by-turn audio instructions to users on how to reach a departure gate -- or a restroom or a restaurant.

The rolling suitcase, called BBeep, sounds alarms when users are headed for a collision with a pedestrian, researchers said.

Both proved effective in a pair of user studies conducted at Pittsburgh International Airport in the US, they said.

"Despite recent efforts to improve accessibility, airport terminals remain challenging for people with visual impairments to navigate independently," said Chieko Asakawa, a professor at CMU and an IBM Fellow at IBM Research.

Airport and airline personnel are available to help them get to departure gates, but they usually can't explore and use the terminal amenities as sighted people can.

An increasing number of airports have been installing Bluetooth beacons, which can be used for indoor navigation.

However, they are often deployed to enhance services for sighted travellers, not to help blind people, said Kris Kitani, an assistant research professor at CMU.

The NavCog app employs Bluetooth beacons.

The app developed to help blind people navigate independently, previously has been deployed on campuses and in shopping malls, researchers said.

They modified it for use at the airport, where extremely wide corridors make users vulnerable to veering, and for use with moving walkways.

As part of the project, the airport installed hundreds of Bluetooth beacons throughout the facility.

The app gives audio directions to users. It relies on a map of the terminal that has been annotated with the locations of restrooms, restaurants, gates, entrances and ticketing counters.

Ten legally blind people tested the app using a smartphone with good results, traversing the terminal's large open spaces, escalators and moving walkways with few errors.

Most users were able to reach the ticketing counter in three minutes, traverse the terminal in about six minutes, go from the gate to a restroom in a minute and go from the gate to a restaurant in about four minutes.

A team, including researchers from the University of Tokyo and Waseda University in Japan, developed BBeep to help with another problem encountered in airports -- navigating through crowds.

The assistive system has a camera for tracking pedestrians in the user's path and can calculate when there is a potential for collision.

A rolling suitcase itself can help clear the way and can serve as an extended sensing mechanism for identifying changes in floor texture.

BBeep, however, can also sound an alarm when collisions are imminent -- both warning the user and alerting people in the area, enabling them to make room.

A series of beeps begins five seconds before the collision.

The frequency of the beeps increases at 2.5 seconds. When the collision is imminent, BBeep issues a stop sound, prompting the blind user to halt immediately.

In tests at the airport, six blind participants each wheeled BBeep with one hand and used a white cane in the other as they manoeuvred through crowded areas.

They were asked to walk five similar routes in three modes -- one where the suitcase gave no warnings, another in which the warnings could only be heard by the user through a headset and another in which warnings were played through a speaker.

The researchers said the speaker mode proved most effective, both in reducing the number of pedestrians at risk of an imminent collision and in reducing the number of pedestrians in the user's path.