Using optical cues, researchers have showcased that a network of energy-harvesting sensor nodes equipped with onboard cameras can determine each camera’s pose and location. This study could be used to monitor the condition of infrastructure such as bridges, industrial equipment monitoring, and home security monitoring.
This capability could help to enable networks of hundreds or thousands of sensors that could operate without batteries or external power and require minimal maintenance. It must be noted that such networks could be part of the Internet of Things (IoT) in which objects can communicate and share information to create smart environments.
Earlier, University of Washington has produced battery-free Radio-frequency identification (RFID) tags called WISPs, which operate at such low power that they can scavenge the energy needed for operation from radio waves. However, the new work shows that these WISPs with onboard cameras, or WISPCams, can use optical cues to figure out where they are located and the direction in which they are pointed.
Alanson P Sample, a research scientist with Disney Research, said, “Once the battery free cameras know their own positions it is possible to query the network of WISPCams for high level information such as all images looking west or sensor data from all nodes in a particular area.”
The researchers used an image processing technique called Perspective-n-Point (PnP) which involves capturing an image of an object and then comparing it with a second image in which four LEDs in a known configuration illuminate the object. This technique helped the camera in estimating the position of the objects within a few centimetres.