METHOD AND SYSTEM FOR DETECTING MOTION

Abstract

A method for detecting motion is provided. The method includes: detecting a motion of a body in order to generate motion data; detecting a location of an allowed movable body in order to generate location data; and determining whether the motion of the body is a motion of the allowed movable body based on at least the motion data and the location data. A security system for verifying a detected motion is also provided. The system includes: a motion detection system; a location detection system; and a processing unit configured to determine whether motion detected by the motion detection system is a motion of the allowed movable body. The system may be for performing the method of detecting motion.

Claims

1. A method for detecting motion, the method comprising: detecting a motion of a body in order to generate motion data; detecting a location of an allowed movable body in order to generate location data; and determining whether the motion of the body is a motion of the allowed movable body based on at least the motion data and the location data.

2. The method of claim 1, wherein the detecting of a motion of a body and the detecting of a location of an allowed movable body are performed in a predetermined space.

3. The method of claim 1, wherein the allowed movable body is a pet.

4. The method of claim 1, wherein the allowed movable body is associated with a location indicator.

5. The method of claim 4, wherein detecting the location of an allowed movable body comprises: sending at least one location request signal to the location indicator; and receiving at least one location signal from the location indicator in response to the location request signal.

6. The method of claim 5, wherein detecting the location of an allowed movable body comprises measuring a time delay between the location request signal being sent and the location signal being received by a location detector in order to calculate a distance between the allowed movable body and the location detector.

7. The method of claim 4, wherein at least three location request signals are sent each by one of three location detectors to the location indicator and a location signal is received from the location indicator at each of the three location detectors in response to each location request signal, and wherein trilateration is carried out based on the three location signals in order to determine the location of the location indicator associated with the allowed movable body.

8. The method of claim 1, wherein the determination of whether the motion of the body is a motion of the allowed movable body based on at least the location data and the motion data comprises determining whether the allowed movable body is in a location where it could have produced the detected motion.

9. The method of claim 1, wherein the method further comprises triggering an alarm when a determination is made that the motion of the body is not a motion of the allowed movable body.

10. A security system for verifying a detected motion, the security system comprising: a motion detection system configured to detect a motion of a body and generate motion data based on the motion of the body; a location detection system configured to detect a location of an allowed movable body and generate location data based on the location of the allowed movable body; and a processing unit configured to receive the motion data and the location data and determine whether the motion detected by the motion detection system is a motion of the allowed movable body.

11. The system of claim 10, wherein the location detection system comprises a location indicator associated with the allowed movable body.

12. The system of claim 11, wherein the location detection system is arranged to detect the location of an allowed movable body by: sending at least one location request signal from a location sensor to the location indicator; and receiving at least one location signal at the location sensor from the location indicator in response to the location request signal.

13. The system of claim 10, wherein the location detection system comprises a plurality of location detection sensors and the motion detection system comprises a plurality of motion detectors.

14. An alarm system configured to carry out the method of claim 1.

15. A method of adapting a pre-existing security system so that it is configured to perform the method of claim 1.

Description

DRAWING DESCRIPTION

[0079] Certain embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0080] FIG. 1 is a flow diagram of a method of verifying a motion;

[0081] FIG. 2a is a schematic diagram illustrating sending a location request signal;

[0082] FIG. 2b is a schematic diagram illustrating receiving a location signal;

[0083] FIG. 3 is a schematic diagram of a security system; and

[0084] FIG. 4 is a schematic diagram illustrating how the location of an allowed movable body may be determined.

DETAILED DESCRIPTION

[0085] A method 1 for verifying a detected motion in a household with an allowed movable body that is a pet is shown in FIG. 1. Although this example is a household and the movable body is a pet, the invention may be applicable to any space that can be monitored, e.g. for use with any security system, and/or any allowed movable body.

[0086] The allowed movable body, in this case a pet, has an associated location indicator, e.g. a tag attached to its collar. The method starts at step 2, where an alarm system is in an operable mode and motion detectors of a motion detection system are monitoring a predetermined region of the household for any signals indicating movement. When a signal indicating movement is detected by any one of the motion detectors the detector is triggered at step 3.

[0087] Following the triggering of a motion detector, the method proceeds to step 4, where the motion detector collects the signal(s) indicating motion. For example, this could include a passive infrared signal of the body that is moving. At step 5, the characteristic parameters of this signal are extracted; these characteristic parameters are the generated motion data of the present invention. In the case of a passive infrared signal these could for example include its amplitude, duration and frequency, amongst other parameters. These characteristic parameters are then sent to a central unit (i.e. a processing unit) of the alarm system at step 6.

[0088] Following the triggering of the motion detector, the method also proceeds to step 7 (e.g. in parallel to proceeding to step 3 described above), where the system sends a position request to the central unit. At step 8, in response to the position request, the central unit sends an activating signal to the location detection system requesting the location of the pet. The location detection system comprises a number of location sensors, preferably three, and upon receiving the activating signal from the central unit, each of the location sensors sends a location request signal to the tag attached to the pet.

[0089] When the tag receives a location request signal from a location sensor it sends a location signal in response back to the location sensor. The location detection system then calculates the distance between the tag and the location sensor based upon the time delay between the location request signal being sent from the location detector and the location signal being detected by the location sensor. This occurs for each of the three location sensors. The distance calculation method is further detailed in FIGS. 2a and 2b.

[0090] FIG. 2a schematically illustrates the location detector 13 sending a radio frequency pulse (the location request signal 14) towards the tag 15 and hence also the pet. The time between the location request signal being sent and received by the tag is t1.

[0091] FIG. 2b illustrates the pet tag 15 sending a radio frequency pulse (the location signal 16) back towards the detector 13. This location signal 16 is sent from the pet tag 15 after the tag receives the location request signal 14 and after a known added time delay of t2 that takes into account a delay in processing of the location request signal 14 and sending of the location signal 16 by the tag. The location signal 16 is then received back at the location detector; the time between the location signal being sent from the tag and received by the location detector is t3. The total time, t4, between the sending of the location request signal and the receiving of the location signal at the location sensor is the sum of t1, t2 and t3. As both the location request signal and the location signal are radio frequency pulses, and the delay time t2 is known, the distance between the tag and the location detector can be calculated as: (t4t2)/(2.Math.c), where c is the speed of light (i.e. the speed of radio waves).

[0092] This calculation treats any movement of the tag during the delay time t2 as negligible. This calculated distance between the tag and the detector is used to generate location data of the pet.

[0093] Turning back to the method shown in FIG. 1, at step 9 the calculated distance (location data) is then sent from the location detection system to the central unit.

[0094] At steps 10 and 11, the central unit makes a determination about whether or not the signal indicating a motion of a body originated from the pet. If is determined that the signal originated from the pet, or it is likely that this is the case, the method returns to start 2 and the alarm system, continues monitoring for motion in the predetermined area as normal. If the signal indicating motion could not have originated from the pet then a determination is reached that it must have originated from an intruder and the alarm is triggered at step 12.

[0095] An alarm system 20 which may perform the method described above is shown schematically in FIG. 3. Alarm system 20 is configured to monitor a household 21, which in this case comprises three rooms 22, 23, 24. The alarm system 20 comprises location detection system 25, motion detection system 26 and central unit 27.

[0096] A pet with tag 15 is shown in room 23 and an intruder 29 is shown in room 24.

[0097] The motion detection system 20 comprises three motion detectors 30, one in each room and is configured to detection any motion of a body in the rooms. The location detection system comprises three location detection sensors 31, one in each room. The motion detectors and the location detectors are part of the same detector units 32.

[0098] The intruder 29 triggers the motion detector 30 in room 24 and the motion detector 31 collects and sends motion data 33 to central unit 27. This data can be sent via a wireless or wired link to the central unit 27.

[0099] The central unit 27 then sends an activating signal to the location detection system 26 requesting the location of the pet and the location detectors 31 each send location request signals to the tag 15. In response to each location request signal, the tag sends corresponding location signals to the respective location detectors and the distance to each detector (distances 34, 35 and 36 respectively) is calculated in line with the method described above in relation to FIGS. 2a and 2b.

[0100] The distances 34, 35, 36 (the location data) to each location sensor are sent via wired or wireless link to the central unit 27 which calculates, e.g. triangulates or trilaterates, the position of the tag (and pet) and makes a determination about whether the motion of the body is a motion of the allowed movable body based on at least the motion data and the location data.

[0101] For example, in the case illustrated in FIG. 3, the motion of a body occurred in room 24 and the pet location is determined to be in room 23, therefore it may be determined that the detected motion could not have originated from the pet and so an intruder has been detected. The alarm system would therefore trigger the alarm.

[0102] The method of generating location data, specifically the precise location of a pet via trilateration is shown in two dimensions in FIG. 4.

[0103] Here, once distances 34, 35 and 36 from respective motion detection sensors 31 have been calculated, arcs 37, 38, 39 can be mapped that correspond to those distances. The point at which these arcs overlap is the exact location of the tag, and thus the allowed movable body (the pet).

[0104] The method and system may use any known method and system to detect location and/or any known method and system to detect the location of an allowed movable body.

[0105] Whilst the above describes an example with one allowed movable body, there may be a plurality of allowed movable bodies each with an associated location indicator, e.g. tag.

[0106] Whilst various aspects of the present invention have been described above with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined by the claims. Therefore, it is intended that the invention not be limited to the particular embodiment(s) and examples disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.