The University of Massachusetts Amherst

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Underground PERCEPTion

Technology developed at UMass Amherst will help the visually impaired navigate Boston subway
  • Electronic tag for visually impaired on elevator sign

Subways are complex, changing environments that present special challenges for the visually impaired. PERCEPT is operated by a gesture-based user interface on smartphones that enables visually impaired users to interact with their environment in real time. 

UMass Amherst professor Aura Ganz has developed an electronic navigation system called PERCEPT, a seeing-eye directory for the blind and visually impaired which will provide them with verbal directions, electronic signs, and a virtual information booth for finding their way around subway stations in Boston.

Ganz, a faculty member in the UMass Electrical and Computer Engineering Department has received a two-year, $238,321 grant from the Massachusetts Bay Transportation Authority (MBTA) to install a prototype of her electronic navigation system for the visually impaired in the Arlington Metro Station.

When in place, PERCEPT can be utilized by any visually impaired individual equipped with a smartphone, a special Interactive Metro Spaces (IMS) application loaded with pre-set navigation instructions, and a near field communication (NFC) set of standards that allows smartphones to communicate with the PERCEPT NFC tags deployed throughout the station.

As Ganz explains, “Independent navigation through unfamiliar indoor spaces is beset with barriers for the visually impaired. A task that is trivial and spontaneous for the visioned population has to be planned and coordinated with other individuals for the visually impaired.”

Independent sight-impaired individuals typically receive training from an orientation and mobility instructor in order to accommodate themselves to buildings they need to visit regularly, but subway stations are much more complex spaces. Unlike an office building, a subway station has no general flow or layout. Moreover, the subway layout can change, depending on time of day. For example, gates open at rush hour are closed at other times. Escalators move up sometimes and then down at others.

Signage is usually placed out of sight from those with low-functioning vision. The high level of ambient noise in the underground atmosphere makes it harder for the visually impaired to use their sense of hearing and detect openings, follow the flow of traffic, and generally navigate through space. Indeed, as noted by the MBTA and the Massachusetts Commission for the Blind, no deployed technological solutions exist that provide accurate and affordable navigation instructions in subway systems.

 Not until now, that is.

According to Ganz, “We will develop a prototype of an accurate and affordable navigation system for the visually impaired in subway stations. The prototype will be piloted in Arlington Metro Station of the MBTA and will be initially tested with visually impaired users as volunteers.”

The proposed system is innovative because it incorporates several new paradigms. First, it features “interactive spaces,” which relate to users in real time and accounts for their changing location throughout the station. Next, PERCEPT is operated by a gesture-based user interface on the smartphone that enables visually impaired users to interact with the space in the station. Finally, the system will offer detailed navigation instructions with safe navigation fundamentals.

When PERCEPT is in place at the Arlington Metro, NFC tags will be deployed at specific landmarks determined by an orientation and mobility instructor. Ganz cites the navigation experience of a hypothetical user, named Alice, to illustrate how PERCEPT will work in Arlington Station. Alice carries her smartphone that includes the IMS application. After choosing the destination (e.g. inbound), the IMS app will provide navigation instructions, either when the smartphone touches the NFC tag or when she swipes its screen for Next instructions.

Once Alice reaches the entrance to the station, she places her phone over the NFC tag located there. When the phone scans the tag, the app says: “Your current starting station is Arlington Main entrance, please proceed down the stairs along the right-side wall. When you get to the bottom of the stairs, scan the card on the wall to your immediate right, or swipe Next.”

Alice proceeds down the stairway and identifies the next NFC tag located at the bottom of the stairs. She places her phone over the tag, and the app says: “Turn left and follow your right-hand wall past the elevator until you reach the opening and then swipe Next for further instructions.”

After Alice identifies the opening, she swipes Next on her phone and the app says: “Continue to follow your right-hand wall into the opening. This is a long hallway that will lead into the main lobby. Swipe Next when reaching the end of the hall.” In this way, the navigation system will continue to direct Alice to her destination.

Before being put into use, the new navigation system will be thoroughly tested by 10 visually-impaired subjects recruited by Meg Robertson, certified orientation and mobility specialist with more than 25 years of experience from the Massachusetts Commission for the Blind in Boston.

As Ganz observes, “PERCEPT can significantly alleviate the challenges introduced above.”

The PERCEPT system was developed with the cooperation of the Massachusetts Orientation and Mobility division of the Massachusetts Commission for the Blind using approximately $400,000 in funding from the National Institute of Health/National Eye Institute.

UMass Amherst News Office

Banner image (courtesy Karen Hayes):  The blue button in this banner image captures the look of current NFC tags in use on the UMass Amherst campus. A more rugged design is envisioned for MBTA signage.