Radio frequency identification tags adapted for localization and state indication

摘要

An embodiment of the present invention provides a radio frequency identification (RFID) tag, comprising at least one light emitting diode (LED) that is controlled by the RFID's logic and powered by the RFID's power harvesting circuit, wherein the RFID tag is capable of being interrogated by an RFID reader and reporting its unique identification number by RF backscatter and/or controlling the illumination state of the at least one LED.

主权项

1. An apparatus, comprising:
a wirelessly-powered radio frequency identification (RFID) tag with at least one light emitting diode (LED) that is powered by said RFID's power harvesting circuit in response to a tag specific illumination command; controllers to control the illumination state of said at least one LED and to automatically localize the RFID tag associated with a blinking LED by performing the action of filtering to accentuate intensity discontinuities and deemphasizes linear or flat regions, thresholding to ensure that only bright red light sources are considered, K-means clustering to ensure that only sufficiently large regions are considered, and selecting pixels whose on-off rate is within a given range; wherein said wirelessly-powered RFID tag powers said LED to provide bright duty-cycled illumination by discharging a storage capacitor when a sufficient operating voltage is reached.