RADIO FREQUENCY IDENTIFICATION TAGS ADAPTED FOR LOCALIZATION AND STATE INDICATION

• US 20090167495A1
• Filed: 12/31/2007
• Published: 07/02/2009
• Est. Priority Date: 12/31/2007
• Status: Active Grant

• Current Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Original Assignee: Intel Corporation
• Inventors: Yeager, Daniel, Rahimi, Ali, Smith, Joshua R.
• Granted Patent: US 8,222,996 B2
• Time in Patent Office: Days
• US Class Current: 340/10.100
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/07703 the interface being visual

Abstract

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.

Claims

1. An apparatus, comprising:

a radio frequency identification (RFID) tag with at least one light emitting diode (LED) that is controlled by said RFID'"'"'s logic and powered by said RFID'"'"'s power harvesting circuit.

2. The apparatus of claim 1, wherein said 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 said at least one LED.

3. The apparatus of claim 2, wherein said illumination is controlled either by an explicit LED-control command from said RFID reader, or locally by said RFID tag.

4. The apparatus of claim 3, wherein said LED is configured to provide visual feedback to a human operator, or to a video camera/machine vision system and wherein said vision system is capable of being mounted on a robot for localization or in a fixed configuration.

5. The apparatus of claim 1, wherein said RFID tag powers said LED when a sufficient operating voltage is reached, which discharges its storage capacitor and wherein when the minimum operating voltage is reached, the LED is turned off, at which point the storage capacitor recharges and therefore said LED flashing rate is proportional to the input power, but the brightness of any single flash is constant.

6. The apparatus of claim 4, wherein said camera light collection duty cycle is set high by setting a shutter time to be as close as possible to said camera frame rate to enable observation of said at least one LED included with said RFID tag by said camera.

7. The apparatus of claim 6, wherein said RFID tag is adapted to enable a pair of stereo cameras to be used to automatically localize the 3D location of said at least one LED by using a blink detection algorithm that locates the LED in both camera views, and stereo triangulation locates the LED.

8. The apparatus of claim 7, wherein said blink detection uses temporal filtering so an image series can be low-pass-filtered to extract a steady component of a scene, and then subtracts said low-pass-filtered image from each new frame to yield a high pass filtered image stream to enable pixels of interest to be identified by applying an energy threshold to said temporally filtered image stream.

9. A method, comprising:

including at least one light emitting diode (LED) with a radio frequency identification (RFID) tag that is controlled by said RFID'"'"'s logic and powered by said RFID'"'"'s power harvesting circuit.

10. The method of claim 9, wherein said 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 said at least one LED.

11. The method of claim 10, further comprising controlling said illumination by either an explicit LED-control command from said RFID reader, or locally by said RFID tag.

12. The method of claim 11, further comprising configuring said LED to provide visual feedback to a human operator, or to a video camera/machine vision system and wherein said vision system is capable of being mounted on a robot for localization or in a fixed configuration.

13. The method of claim 9, further comprising powering by said RFID tag said LED when a sufficient operating voltage is reached, which discharges its storage capacitor and wherein when the minimum operating voltage is reached, the LED is turned off, at which point the storage capacitor recharges and therefore said LED flashing rate is proportional to the input power, but the brightness of any single flash is constant.

14. The method of claim 12, further comprising setting said camera light collection duty cycle high by setting a shutter time to be as close as possible to said camera frame rate to enable observation of said at least one LED included with said RFID tag by said camera.

15. The method of claim 14, further comprising adapting said RFID tag to enable a pair of stereo cameras to be used to automatically localize the 3D location of said at least one LED by using a blink detection algorithm that locates the LED in both camera views, and stereo triangulation locates the LED.

16. The method of claim 15, further comprising using by said blink detection temporal filtering so an image series can be low-pass-filtered to extract a steady component of a scene, and then subtracts said low-pass-filtered image from each new frame to yield a high pass filtered image stream to enable pixels of interest to be identified by applying an energy threshold to said temporally filtered image stream.

17. A radio frequency identification (RFID) tag, comprising:

at least one light emitting diode (LED) that is controlled by said RFID'"'"'s logic and powered by said RFID'"'"'s power harvesting circuit, wherein said 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 said at least one LED.

18. The radio frequency identification (RFID) tag of claim 17, wherein said illumination is controlled either by an explicit LED-control command from said RFID reader, or locally by said RFID tag.

19. The radio frequency identification (RFID) tag of claim 18, wherein said LED is configured to provide visual feedback to a human operator, or to a video camera/machine vision system and wherein said vision system is capable of being mounted on a robot for localization or in a fixed configuration.

20. The radio frequency identification (RFID) tag of claim 17, wherein said RFID tag powers said LED when a sufficient operating voltage is reached, which discharges its storage capacitor and wherein when the minimum operating voltage is reached, the LED is turned off, at which point the storage capacitor recharges and therefore said LED flashing rate is proportional to the input power, but the brightness of any single flash is constant.