A METHOD OF IDENTIFICATION OF AN ITEM USING PHASE DATA FOR MOVEMENT DETECTION

Abstract

A method and system for identification of an item is provided, wherein the system comprises includes a conveyor belt, a conveyor belt controller and a reader operable to receive at least one reading from at least one tag attached to the item and extract from the reading a measurement of the phase of the signal transmitted by the tag and received at at least one antenna of the reader, the antenna being adapted to be arranged at a read point along the conveyor belt, wherein the conveyor belt controller is configured to start the conveyor belt at a first time instant, after the item has been placed on the conveyor belt, and to stop the conveyor belt at a second time instant, when the item has passed the antenna of the reader.

Claims

1-6. (canceled)

7. A method of identification of an item in a system, the system comprising: a conveyor belt, a conveyor belt controller, a reader comprising an antenna, the antenna being arranged at a read point along the conveyor belt and configured for receiving a signal transmitted from a tag, the reader being operable to receive at least one reading from the tag via the antenna and extract from the reading a measurement of the phase of the signal transmitted by the tag and received by the antenna of the reader, wherein the method comprises: placing an item on the conveyor belt; by the reader receiving readings from the tag and extracting signal phase measurements from the readings; by the conveyor belt controller starting the conveyor belt at a first time instant t.sub.1 after the item has been placed on the conveyor belt; by the conveyor belt controller stopping the conveyor belt at a second time instant t.sub.2, when the item has passed the antenna of the reader, the first and second time instants t.sub.i, t.sub.2 defining a time window W; and by the reader associating the tag to the item if the pattern of the phase measurements of the tag comprises changing phase values within the time window and substantially constant phase values before and after the time window W corresponding to the movement of the item on the conveyor belt only within the time window whereby the identification of the item is accomplished.

8. The method according to claim 7, wherein the method comprises defining three periods, of which the first period is before the time window W, the second period is within the time window until the tag has passed the antenna, and the third period is after the time window; wherein the method further comprises by the reader calculating an accumulated phase change for each period and comparing the phase measurements to a first and a second threshold and further considering the tag to be still if the accumulated phase change is below a first threshold and considering the tag to be moving if the accumulated phase change is above a second threshold.

9. The method according to claim 8, wherein the method comprises setting the first threshold within the range of 50-100 degrees and the second threshold within the range of 100-200 degrees.

10. The method according to claim 7, wherein the system comprises a detector for detecting that the item has been placed on the conveyor belt; the method further comprising by a detector detecting that the item has been placed on the conveyor belt and as a consequence of the detection, by the conveyor belt controller starting the conveyor belt without intervention by a user.

11. The method according to claim 10, wherein the detector comprises a photocell or a weight or a pressure sensor, and wherein the method comprises detecting by the photocell or weight or pressure sensor that the item has been placed on the conveyor belt.

12. The method according to claim 7, wherein the system comprises a self-service bag drop unit and wherein the method comprises by the conveyor belt controller informing the self-service bag drop unit of the time instant when the item started to move on the conveyor belt and the time instant when the item stopped under the antenna of the reader; by the self-service bag drop unit associating the tag to the item if the tag is found to have moved within the time window W but has been static in time intervals before and after the time window.

13. The method according to claim 7, wherein the tag is an RFID tag, and the antenna is an RF antenna, and wherein the method comprises transmitting signals by the tag and reading the signals by the antenna.

14. The method according to claim 7, wherein the method comprises providing a reading that comprises a timestamp for receipt of the signal from the tag, a signal strength indicator (RSSI) for the signal, the signal phase value of the signal, and information about a communication channel for the signal.

15. The method according to claim 14, wherein the method comprises providing a signal strength threshold and discarding phase measurements when a received signal has a strength under the signal strength threshold.

16. The method according to claim 7, wherein the item is a suitcase, or a bag, or a package, and the method comprises identifying the item in an airport.

Description

BRIEF DESCRIPTION

[0022] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0023] FIG. 1: depicted is a top view of a self-service bag drop unit;

[0024] FIG. 2: depicted is a snapshot of phase measurements plotted against time; and

[0025] FIG. 3: depicted is a method of item identification according to embodiments of the invention.

NOTATIONS

[0026] 1: Self-service bag drop unit.

2: Item.

[0027] 3: Conveyor belt.
4: Read point.

5: Tag.

6: Measurement.

7: Passenger.

8: Display.

[0028] 9: Optical scanner.
10: Boarding card.
t.sub.1: First time instant.
t.sub.2: Second time instant.
W: Time window.

DETAILED DESCRIPTION

[0029] FIG. 1 shows an advantageous embodiment of a system 1 for identification of an item 2 in the form of a self-service bag drop unit 1. Note, however, that the system 1 of embodiments of the invention is not limited to be used as a self-service bag drop unit 1 within airport premises, but can also be used for other applications such as in a postal distribution central or a retail distribution center for sorting packages.

[0030] The passenger 7 simply checks-in as usual (e.g., at a check-in kiosk), applies the bag tag 5 embedding an RFID tag to his bag 2 (in this example, the bag is simply a security tray) and moves towards the self-service bag drop unit 1 where he finally places his bag 2 on the conveyor belt 3.

[0031] The passenger 7 may then interact with a display 8 (e.g., a touch screen), which may, for example, visualize messages such as: “Do you want to check-in your bag?”. When the passenger 7 validates the request (e.g., by tabbing the message on the touch screen), the PLC activates the motor of the conveyor belt 3 and the bag 2 is directed towards the read point 4 (e.g., positioned a few meters from the area where the passenger 7 had originally placed his bag 2) under which the bag 2 is stopped again. At the topside of the read point 2 sits an RFID antenna of an RFID reader, which scans all the bag tags 5 in its coverage. Subsequently, the reader identifies which bag tag 5 sits on that bag 2 and sends a feedback to the self-service bag drop unit 1. The passenger 7 may then be asked to confirm that the bag 2 that has just been read is in fact his bag 2 (e.g., by letting an optical scanner 9 read the barcode on his boarding card 10 or by tabbing a “YES” message on the display 8). Afterwards, the bag 2 is checked-in and is transported away from the read point 4, for example, by being transferred to a second conveyor belt.

[0032] The printer at the check-in codes the relevant information in the RFID tag, which is printed together and embedded in the bag tag 5 to apply to the bag 2. The 10 digits code, which is encoded in the barcode on the bag tag 5, is also encoded in the RFID tag via the RFID antenna at the printer.

[0033] A PLC (Programmable Logic Controller) is a low level controller, which makes the conveyor belt 3 run/stop and which tracks the bags 5 by means of photocells positioned along the conveyor belt 3.

[0034] FIG. 2 shows measured phase values 6 in degrees against time in ms for the bag tags 5 under coverage of the reader during time. The time interval depicted in grey represents the time window W, which defines when the bag 2 started to move on the conveyor belt 3 (ref vertical line on the left-hand-side of the time window W) and when the bag 2 stopped under the antenna of the reader (ref vertical line on the right-hand-side of the time window W). It is noticeable that: (i) the phase values 6 remain substantially constant before the time window W; this is due to the fact that the passenger 7 had placed the bag 2 on the conveyor belt 3 and had, for example, spent time interacting with the self-service bag drop unit 1; (ii) the phase values 6 change within the time window W; this is due to the fact that the bag 2 moves on the conveyor belt 3; and (iii) the phase values 6 remain substantially constant after the time window W; this is due to the fact that the bag 2 is stopped under the antenna of the reader (e.g., the bag 2 may be stopped for around 2 sec in order to get some readings and in order to give a result back to the self-service bag drop unit 1).

[0035] The conveyor belt controller may inform the self-service bag drop unit 1 of the time instant t.sub.1 when the bag 2 started to move on the conveyor belt 3 and the time instant t.sub.2 when the bag 2 stopped under the antenna of the reader. If the self-service bag drop unit 1 determines that the bag tag 5 was static in the time interval before the time window W (e.g., from when a weight detected the bag 2 on the conveyor belt 3), that the bag tag 5 moved within the time window W and that the bag tag 5 was static again in a time interval after the time window W, it concludes that the bag tag 5 is associated to that bag 2. In other words, the self-service bag drop unit 1 checks which bag tag 5 has a pattern corresponding to that of the bag 2 on the conveyor belt 3 and accordingly performs the association bag tag-bag.

[0036] For instance, in case the passenger 7 has another bag 2 standing on the side of the conveyor belt 3 while he checks-in his first bag 2, the phase values 6 retrieved by the self-service bag drop unit 1 will substantially be constant for that bag tag 5 along the entire time. Therefore, the self-service bag drop unit 1 will conclude that that bag tag 5 is not associated to the bag 2 that has gone through the read point 4 and will filter it out. Similarly, if another passenger 7 walks by with a bag 2, the phase values 6 associated to that bag tag 5 will constantly vary during time, thus permitting to the self-service bag drop unit 1 to filter out also that bag tag 5.

[0037] FIG. 3 shows a method 100 of identification of an item 2, wherein the method 100 comprises:

providing 101 a system 1 as described above;
the reader receiving 102 one or more readings from the tag 5;
the reader extracting 103 the phase measurements 6 from the readings;
the detector detecting 108 that the item 2 has been placed on the conveyor belt 3;
the conveyor belt controller starting 104 the conveyor belt 3 at a first time instant t.sub.1, after the item 2 has been placed on the conveyor belt 3;
the conveyor belt controller stopping 105 the conveyor belt 3 at a second time instant t.sub.2, when the item 2 has passed the antenna of the reader, the first and second time instants t.sub.1, t.sub.2 defining a time window W;
the reader comparing 107 the phase measurements 6 to a threshold; and
the reader associating 106 the tag 5 to the item 2 if the pattern of the phase measurements 6 of the tag 5 before, within and after the time window W corresponds to the pattern of the movement of the item 2 on the conveyor belt 3;
whereby the identification of the item 2 is accomplished.

[0038] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0039] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements. The mention of a “unit” or a “module” does not preclude the use of more than one unit or module.