Researchers at Purdue University in the US have found a way for public surveillance cameras to send personalised messages to people without knowing who they are.
The real-time end-to-end system called PHADE allows 'private human addressing' that doesn't use the destination's IP or MAC address. Instead it uses motion patterns as the address code for communication so that a smartphone then locally make its own decisions on whether to accept a message. The technology will be discussed at a conference in Signapore in October and the researchers see it as a direct competitor to Bluetooth beacons.
The PHADE system works using a server to receive video streams from cameras to track people. The camera builds a packet by linking a message to the address code and broadcasts the packet. Upon receiving the packet, a mobile device of each of the targets uses sensors to extract its owner's behavior and follow the same transformation to derive a second address code. If the second address code matches with the address code in the message, the mobile device automatically delivers the message to its owner.
"Our technology enables public cameras to send customized messages to targets without any prior registration," said He Wang, an assistant professor in the Purdue Department of Computer Science, who created the technology along with his PhD student, Siyuan Cao. "Our system serves as a bridge to connect surveillance cameras and people and protects targets' privacy."
PHADE protects privacy in two ways - it keeps the users' personal sensing data within their smartphones and it transforms the raw features of the data to blur partial details. The creators named the system PHADE because the blurring process "fades" people's motion details out.
PHADE can be used in places such as a museum, where visitors can receive messages with information about the exhibits they are viewing. The technology also could be implemented in shopping centres to provide consumers with digital product information or coupons.
"PHADE may also be used by government agencies to enhance public safety," said Cao. "For example, the government can deploy cameras in high-crime or high-accident areas and warn specific users about potential threats, such as suspicious followers."
Wang said surveillance camera and security companies would also be able to embed the technology into their products directly as a key feature. He also said this technology has advantages over Bluetooth-based beacons, which have difficulties in adjusting for ranges of transmission and do not allow for context-aware messaging.