JP5749027B2 - Anti-theft device, anti-theft method and anti-theft program - Google Patents

Description

  The present invention relates to an anti-theft device, an anti-theft method, and an anti-theft program for preventing the theft of portable objects such as bicycles, motorcycles, and portable electronic devices.

  Anti-theft devices that prevent theft of bicycles, motorcycles, etc. use acceleration sensors to detect tilt and vibration in the direction of gravity. For example, as shown in FIG. 12, Patent Document 1 discloses an anti-theft device that attaches a biaxial acceleration sensor to an XY plane of a vehicle body and detects acceleration in the XY directions. As shown in FIG. 13, this anti-theft device is attached to a body frame of a motorcycle, for example, when the main stand 6 is raised and the body is lowered, or when the body is moved with the handle 7 The left / right inclination of the vehicle body is detected to determine whether or not it is stolen. Patent Document 2 uses an acceleration sensor to prevent theft of a portable electronic device such as a projector.

JP 2008-162586 A JP 2006-209199 A

  However, the conventional antitheft device has the following problems. In an anti-theft device using an acceleration sensor that detects acceleration in the X, Y, and Z directions, the displacement amount of each axis is compared with a threshold value, and the time of acceleration change with respect to the threshold value has elapsed. Theft is judged by evaluating. However, with such a method for independently determining the amount of change in acceleration in each of the three axes, there is a problem that it is difficult to discriminate between an acceleration change due to an impact or vibration on an object and an acceleration change pattern during a theft operation. there were. Furthermore, there is a problem that it is difficult to determine the theft even in the case of theft of an object whose posture changes even though the acceleration change is small.

  An object of the present invention is to solve the above-described conventional problems and to provide an anti-theft device, an anti-theft method, and an anti-theft program that can easily determine an acceleration pattern during a theft operation.

  The anti-theft device for preventing the theft of an object according to the present invention is a detection means attached to an object and capable of detecting acceleration in the X, Y, and Z directions, and based on the detection result of the detection means. The calculation means for calculating the acceleration vector change amount of the acceleration combined with the acceleration in the direction, the threshold setting means for setting the threshold value, and the acceleration vector change amount calculated by the calculation means and the threshold value are compared. Determining means for determining that the object has been stolen when the acceleration vector change amount is equal to or greater than a threshold value.

  Furthermore, the anti-theft device for preventing the theft of the object of the present invention is a detection means attached to the object and capable of detecting acceleration in the X, Y, and Z directions, and the amount of change in the posture of the object based on the detection result of the detection means. The calculation means for calculating, the threshold value setting means for setting a threshold value, the posture change amount calculated by the calculation means and the threshold value are compared, and when the posture change amount is equal to or greater than the threshold value, the object is Determination means for determining that the theft has been stolen.

  Furthermore, the anti-theft device for preventing the theft of the object of the present invention is a detection means attached to the object and capable of detecting acceleration in the X, Y and Z directions, and based on the detection result of the detection means. Calculating means for calculating the acceleration vector change amount of the acceleration combined with the acceleration in the direction and the posture change amount of the object, threshold setting means for setting a threshold value according to the posture change amount, and the threshold value A determination unit that compares the threshold set by the setting unit with the acceleration vector variation calculated by the calculation unit and determines that the object has been stolen when the acceleration vector variation is equal to or greater than the threshold; .

  Preferably, the determination unit determines that the object has been stolen when the acceleration vector change amount or the posture change amount measured at an arbitrary time interval is continuously equal to or greater than a threshold value a plurality of times. Preferably, the determination unit further compares a reference direction in which a direction in which the object is moved when the object is stolen and a combined acceleration vector of the object, and the combined acceleration vector is within a certain range of the reference direction. Determine that the object has been stolen. Preferably, the anti-theft device further includes user input means capable of setting a theft monitoring period, and the determination means determines the theft during the theft monitoring period. Preferably, the threshold value of the threshold value setting means can be changed via user input means. Preferably, the anti-theft device further includes an alarm means, and the alarm means issues an alarm when it is determined that the theft is determined by the determining means, and the theft information related to being stolen is transmitted to the portable terminal using the communication means. Including one that sends and issues a theft alarm via a mobile device or one that causes the mobile device to display alarm information,

  The anti-theft method for preventing theft of an object according to the present invention sets a step of attaching an acceleration sensor capable of detecting accelerations in the X, Y, and Z directions to an object to be monitored and sets a theft monitoring period of the object to be monitored. A step of calculating an acceleration vector change amount of an acceleration obtained by combining accelerations in the X, Y, and Z directions based on a detection result obtained from an acceleration sensor during the theft monitoring period; and a threshold value of the acceleration vector change amount And comparing the value and determining that the object has been stolen when the acceleration vector change amount is equal to or greater than a threshold value. Further, according to the present invention, there is provided an antitheft method for preventing an object from being stolen, comprising: attaching an acceleration sensor capable of detecting accelerations in the X, Y, and Z directions to an object to be monitored; A step of calculating a posture change amount of the object based on a detection result obtained from the acceleration sensor during the theft monitoring period, and a comparison between the posture change amount and the threshold. Determining that the object has been stolen when the threshold is equal to or greater than the threshold value. Further, according to the present invention, an anti-theft method for preventing theft of an object sets a step of attaching an acceleration sensor capable of detecting accelerations in the X, Y, and Z directions to an object to be monitored, and sets a theft monitoring period of the object to be monitored. And calculating an acceleration vector change amount of acceleration obtained by combining accelerations in the X, Y, and Z directions and an object posture change amount based on a detection result obtained from the acceleration sensor in the theft monitoring period. The step of setting a threshold value according to the posture change amount is compared with the set threshold value and the acceleration vector change amount. When the acceleration vector change amount is equal to or greater than the threshold value, the object is stolen. And a step of determining that Preferably, the determining step determines that the object has been stolen when the acceleration vector change amount or the posture change amount measured at a plurality of time intervals is equal to or greater than a threshold value a plurality of times. Preferably, the step of determining further compares a reference direction in which the direction in which the object is moved when the object is stolen and a combined acceleration vector of the object, and the combined acceleration vector is within a certain range of the reference direction. When it is determined that the object has been stolen.

  The anti-theft program according to the present invention is a program executed by an anti-theft device that attaches an acceleration sensor capable of detecting acceleration in the X, Y, and Z directions to an object to be monitored and prevents the object from being stolen. A step of setting a theft monitoring period of an object to be calculated, a step of calculating an acceleration vector change amount of an acceleration obtained by synthesizing accelerations in the X, Y, and Z directions based on a detection result obtained from an acceleration sensor, and the acceleration vector change Comparing the amount with a threshold value and determining that the object has been stolen when the acceleration vector change amount is equal to or greater than the threshold value. Further, the anti-theft program of the present invention includes a step of setting a theft monitoring period of an object to be monitored, a step of calculating an attitude change amount of the object based on a detection result obtained from the acceleration sensor, and a threshold value of the attitude change amount. And comparing the value and determining that the object has been stolen when the posture change amount is equal to or greater than the threshold value. Furthermore, the anti-theft program of the present invention is based on the detection result obtained from the acceleration sensor in the anti-theft monitoring period based on the step of setting the anti-theft monitoring period of the object to be monitored and the detection result obtained from the acceleration sensor. A step of calculating an acceleration vector change amount of an acceleration obtained by combining accelerations in the X, Y, and Z directions and an object posture change amount, a step of setting a threshold value according to the posture change amount, and Comparing the threshold value with the acceleration vector change amount and determining that the object has been stolen when the acceleration vector change amount is equal to or greater than the threshold value. Preferably, the determining step determines that the object has been stolen when the amount of change measured at a plurality of time intervals is equal to or greater than a threshold value a plurality of times. Preferably, the step of determining further compares a reference direction in which the direction in which the object is moved when the object is stolen and a combined acceleration vector of the object, and the combined acceleration vector is within a certain range of the reference direction. When it is determined that the object has been stolen.

  According to the present invention, the theft of an object is determined based on the acceleration vector change amount of the acceleration obtained by synthesizing the accelerations in the three axis directions, so the acceleration change pattern during the theft operation is determined from the acceleration change due to impact or vibration. As a result, the accuracy of the theft determination can be improved as compared with the conventional one. Further, according to the present invention, since the object theft is determined based on the amount of change in the posture of the object, the theft of the object can be determined regardless of the acceleration change due to vibration or impact. Further, according to the present invention, the threshold value is varied based on the amount of change in posture of the object, and the theft of the object is determined by comparing the varied threshold value and the acceleration vector variation amount. If the posture change amount of the object is large, the threshold value is increased, and if the posture change amount of the object is small, the threshold value is decreased to cope with various theft patterns of the object.

It is a figure explaining the outline | summary of the antitheft device of this invention. It is a block diagram which shows the structure of the antitheft device which concerns on the Example of this invention. It is a block diagram which shows the functional structure of the theft determination part shown in FIG. It is a timing chart explaining operation of each part of an antitheft device. It is a block diagram which shows the other structural example of the antitheft apparatus which concerns on the Example of this invention. It is a flowchart explaining operation | movement of the antitheft apparatus which concerns on the Example of this invention. FIG. 7A is a graph of measured data of triaxial acceleration during a theft operation, and FIG. 7B is a graph showing an absolute value of a combined vector of the measured data of triaxial acceleration in FIG. 7A. . It is a flowchart which shows the theft determination operation | movement which concerns on 2nd Example of this invention. It is a graph which shows the example of a change of the threshold value by 2nd Example of this invention. It is a block diagram which shows the functional structure of the theft determination part which concerns on 3rd Example of this invention. It is a figure which shows the example of the movement locus | trajectory of XY plane at the time of a theft operation | movement. It is a flowchart explaining operation | movement of the antitheft apparatus which concerns on 3rd Example of this invention. It is a figure which shows an example of the conventional antitheft device. It is a figure which shows the example of attachment to the motorcycle of the conventional antitheft device.

  Next, an outline of the antitheft device according to the embodiment of the present invention will be described. The antitheft device of the present invention prevents theft of various portable objects such as motorcycles, bicycles, mobile phones, smartphones, digital cameras, laptop computers, bags, suitcases and the like. The anti-theft device of the present invention uses an acceleration sensor capable of detecting acceleration in each of the X-axis, Y-axis, and Z-axis directions, and such an acceleration sensor is attached to an object to be monitored.

  FIG. 1 shows three-axis detection output of the acceleration sensor when the acceleration sensor is attached to the object to be monitored, that is, the coordinates of the combined vector of the detection output of the X-axis, Y-axis, and Z-axis, the posture change and movement of the object Represents the relationship. When an acceleration sensor is installed on the object to be monitored, the acceleration sensor detects a combined vector V0 of gravitational acceleration. The stationary position of the object at this time is set as a reference coordinate a. For example, when the acceleration sensor is installed on a plane parallel to the XY plane of the object to be monitored, if the object is in a stationary state, the combined vector of the gravitational acceleration of the acceleration sensor is only in the Z direction, and therefore the reference coordinate a Corresponds to the Z-axis direction. On the other hand, when the acceleration sensor is installed at an inclination from the XY plane of the object to be monitored, gravitational acceleration occurs in the X, Y, and Z directions of the acceleration sensor. It does not match.

  FIG. 1 shows an example in which the acceleration vector of the object has moved from the reference coordinate a to the coordinates b1 ′, b2 ′,... Bn ′ after movement, and the movement locus of the acceleration vector of the object at this time is L. The accelerations in the respective axial directions output from the acceleration sensor are combined, and the acceleration vector change amount ΔVa (ΔVa1, ΔVa2,... ΔVan) of the combined acceleration vector is calculated. In the figure, the acceleration vector change amounts ΔVa1 and ΔVa2 when the acceleration combined vector of the object is moved to the moved coordinates b1 'and b2' are indicated by broken-line arrows. In addition, the coordinates b (b1, b2,..., Bn) after the posture change of the object can be obtained from the acceleration vector change amount of the acceleration vector synthesized by the acceleration sensor. Posture change amount Δga (Δga1, Δga2,... Δgan) is calculated. The posture change amount of the object is expressed by Δga1 = V1−V0, Δga2 = V2−V0,... Δgan = Vn−V0. V0 is a combined vector of gravitational acceleration when the object is stationary at the reference coordinate a, and V1, V2,... Vn are at coordinates b1, b2,. V0 = V1 = V2 =... = Vn.

  When acceleration or vibration is applied or tilted due to a theft act on the object to be monitored, the acceleration combined vector of the object moves from the reference coordinate a to the coordinate b ′ after the movement as indicated by the vector locus L. . At this time, the acceleration vector change amount ΔVa generated in the process from the reference coordinate a to the coordinate b ′ after movement and the posture change amount Δga from the reference coordinate point a are calculated, and these change amounts are used alone or in combination. An object theft is determined. In the present invention, when one or both of the acceleration vector change amount ΔVa and the posture change amount Δga meets a set threshold value condition, it is determined that the object has been stolen. By using such a determination method, compared to the conventional method of determining theft from the amount of acceleration change of each axis, the acceleration during the theft operation is determined from the change in acceleration when an impact or vibration is applied to the object. Pattern discrimination accuracy is improved, and more accurate theft judgment can be performed.

  Next, an antitheft device according to an embodiment of the present invention will be described. FIG. 2 is a block diagram showing the configuration of the antitheft device according to the embodiment of the present invention. The anti-theft device 10 according to the present embodiment includes an acceleration sensor 20 attached to an object to be monitored, a signal processing unit 30 that processes a detection signal output from the acceleration sensor 20, and a result processed by the signal processing unit 30. The theft determination unit 40 that performs the theft determination based on the above, the alarm unit 50 that issues an alarm when the theft determination unit 40 determines the theft, the user input unit 60 that receives input from the user, and supplies power to each unit And a power supply unit 70.

  The acceleration sensor 20 detects accelerations in at least the X-axis, Y-axis, and Z-axis directions, and provides a detection signal indicating the acceleration of each axis to the signal processing unit 30. The acceleration sensor 20 includes various types such as a known semiconductor type, piezoresistive type, and electrostatic capacitance type, and any type may be used. Further, the acceleration sensor 20 may be one in which three acceleration sensors that respectively detect the X axis, the Y axis, and the Z axis are mounted on the circuit board, or an acceleration sensor that detects the biaxial directions of the XY axes. An acceleration sensor for detecting the Z-axis direction may be mounted on the circuit board, or an acceleration sensor for detecting the X-axis, Y-axis, and Z-axis may be mounted on the circuit board.

  The signal processing unit 30 receives the detection signal from the acceleration sensor 20, digitally converts the detection signal, calculates an acceleration obtained by synthesizing three-axis acceleration from the digitized detection signal, and calculates the acceleration vector change amount ΔVa. calculate. The synthesized acceleration is sampled at a predetermined cycle, whereby an acceleration vector change amount ΔVa (ΔVa1, ΔVa2,... ΔVan) is calculated. The sampling period can be arbitrarily changed via the user input unit 60. The signal processing unit 30 further detects the coordinate b (b1, b2,... Bn) after the posture change from the synthesized acceleration, and calculates the posture change amount Δga (Δga1, Δga2,... Δgan). The calculated acceleration vector change amount ΔVa and posture change amount Δga are provided to the theft determination unit 40. The theft determination unit 40 performs the theft determination based on the acceleration vector change amount ΔVa and the posture change amount Δga received from the signal processing unit 30. The signal processing unit 30 and the theft determination unit 40 can be configured using, for example, a semiconductor device using a microcontroller, a microprocessor, a central processing processor, and the like, and are preferably mounted on a common circuit board together with an acceleration sensor. The More preferably, the microcontroller or the like can store a program for performing the theft determination in the memory and execute various programs of the anti-theft device by executing the program.

  The alarm unit 50 issues an alarm when the theft determination unit 40 determines that the theft is theft. The alarm may be, for example, an alarm sound from a speaker or a flashing light that appeals visually. The user input unit 60 enables input of an instruction for starting the anti-theft device 10, an instruction for stopping it, an instruction for stopping an alarm by the alarm unit 50, and the like. Further, the alarm unit 50 can include wireless or wired communication means. In a preferred example, the alarm unit 50 uses communication means to transmit alarm information informing that a theft has occurred to a mobile terminal such as a mobile phone or a smartphone, so that the mobile terminal issues an alarm, You may make it display the predetermined information regarding an alarm on a display part. Further, the alarm unit 50 may transmit alarm information to an information terminal such as a personal computer connected to the network via a communication unit. It is desirable to register the destination (address, telephone number, URL, etc.) to which the alarm information is transmitted in advance in the memory of the alarm unit 50.

  The power supply unit 70 makes it possible to supply necessary power to each unit of the anti-theft device 10. If the power held by the object to be monitored is used, the power supply unit 70 supplies the power of the object to each unit, while the power of the object to be monitored cannot be used. The power supply unit itself supplies power to each unit using a battery. Moreover, as will be described later, it is desirable that the power supply unit 70 supplies power to each unit in synchronization with the activation of the anti-theft device 10 by the user input unit 60, thereby reducing wasteful power consumption.

FIG. 3 is a block diagram illustrating a functional configuration of the theft determination unit 40. The theft determination unit 40
A determination unit 100 that performs theft determination, a threshold value holding unit 110 that holds a threshold value Th, and a counter 120 are provided. The threshold value holding unit 110 is preferably composed of a rewritable nonvolatile memory, and holds a threshold value Th corresponding to an object to be monitored. For example, a desired threshold value Th can be set in the threshold value holding unit 140 via the user input unit 60.

  In the first preferred embodiment, the determination unit 100 compares the acceleration vector change amount ΔVa received from the signal processing unit 30 with the threshold value Th, and determines theft based on the comparison result. That is, if the determination unit 100 determines that the acceleration vector change amount ΔVa is equal to or greater than the threshold value Th, the determination unit 100 increments the count value of the counter 120 by one, and the acceleration vector change amount ΔVa is smaller than the threshold value Th. If it is determined, the count value of the counter 120 is reset to “0”. Thereby, the counter 120 stores the number of consecutive times when the acceleration vector change amount ΔVa is determined to be equal to or greater than the threshold value Th.

  In the second preferred embodiment, the determination unit 100 compares the posture change amount Δga received from the signal processing unit 30 with the threshold value Th, and determines theft based on the comparison result.

  FIG. 4 is a timing chart for explaining the operation of the antitheft device 40. As shown in the figure, when an instruction for starting the anti-theft device 10 is made at the time T1 from the user input unit 60, the power supply unit 70 responds to each part of the anti-theft device 10 in response to this. Supply power. This power supply corresponds to an enable signal for operating each unit. In addition, when an instruction for terminating the anti-theft device 10 is issued from the user input unit 60 at time T2, in response to this, the power supply unit 70 stops supplying power to each unit. This stoppage of power supply corresponds to a disable signal for stopping the operation of each unit. Thus, a theft monitoring period from time T1 to time T2 is set by user input.

  When each unit is enabled at time T <b> 1, the acceleration sensor 20 detects the X-axis, Y-axis, and Z-axis accelerations and outputs them to the signal processing unit 30. The signal processing unit 30 holds the reference coordinate a of the object in the reference coordinate holding unit, and thereafter, the acceleration vector change amount ΔVa of acceleration synthesized from the X-axis, Y-axis, and Z-axis accelerations at an arbitrary sampling period. The posture change amount Δga is calculated and provided to the theft determination unit 40.

  The theft determination unit 40 clears all the held contents when enabled. In the first preferred embodiment, the determination unit 100 compares the acceleration vector change amount ΔVa with the threshold value Th, and the number of times that the acceleration vector change amount ΔVa is determined to be equal to or greater than the threshold value is a predetermined number m (m is a natural number). It is determined that the theft has been reached. In the second preferred embodiment, the determination unit 100 compares the posture change amount Δga and the threshold value Th, and when the number of times that the posture change amount Δga is determined to be equal to or greater than the threshold value reaches a predetermined number m, judge.

  In the above example, the enable signal or the disable signal is supplied to each unit by the power supply by the power supply unit 70 or the stop thereof. However, as shown in FIG. The configuration may include a control unit 80 that receives an input. In this case, the power Vcc is supplied from the power supply unit 70 to each unit of the anti-theft device 10, and the control unit 80 supplies an enable signal to each unit in response to the activation instruction from the user input unit 60, A disable signal is supplied to each unit in response to an instruction. Furthermore, in the above example, the theft monitoring period is set according to an instruction from the user input unit 60. However, for example, a theft monitoring period may be set using a timer or the like. .

  Next, the operation of the antitheft device 10 will be described with reference to the flowchart of FIG. First, the theft determination unit 40 determines whether or not it is a theft monitoring period (S101). If it is the theft monitoring period, the signal processing unit 30 holds the reference coordinate a (S102), and calculates the acceleration vector change amount ΔVa and the posture change amount Δga at an arbitrary period based on the detection signal from the acceleration sensor 20. (S103), this is provided by the theft determination unit 40.

  Next, the determination unit 100 holds the received acceleration vector change amount ΔVa and posture change amount Δga (S104), and then, in the first mode, compares the acceleration vector change amount ΔVa with the threshold value Th. In the second mode, the posture change amount Δga is compared with the threshold value Th (S105). When the amount of change is smaller than the threshold value Th, it is determined that the object to be monitored is not applied with an impact, inclination, vibration, or the like corresponding to the theft, and the loop processing from step S103 is performed. Repeated.

  When the acceleration vector change amount Va or the posture change amount Δga is equal to or greater than the threshold value Th, there is a possibility that the object to be monitored is exposed to theft. Is incremented by 1, and it is determined whether or not the incremented counter value has reached m times (S106). If the count value of the counter 120 has not reached m, the processing from step S103 is continued. If it is determined that the acceleration vector change amount ΔVa or the posture change amount Δga is equal to or greater than the threshold value Th continuously m times, it is determined that the object has been stolen (S107).

  If the determination unit 100 determines that the object has been stolen, the determination result is transmitted to the alarm unit 50. In response to the determination result, the alarm unit 50 issues an alarm for notifying that the theft has occurred (S108). The alarm may be continued for a certain time or may be stopped in response to an input from the user input unit 60.

  FIG. 7A is a graph showing measured data of triaxial acceleration during a theft operation, and FIG. 7B is a graph showing the absolute value of the combined acceleration of the acceleration data of FIG. 7A. It is. The vertical axis of the graph represents acceleration, and the horizontal axis represents time. As shown in FIG. 7A, the X-axis acceleration has positive and negative acceleration peak values, and has a large negative acceleration for a relatively long period, while the Y-axis and Z-axis accelerations are positive and negative. Has a peak value of but is immediately converging towards zero. From such an acceleration profile, it is not easy to determine whether an acceleration change due to a temporary impact or vibration on an object has occurred, or whether an acceleration change has occurred during a theft operation.

  On the other hand, as shown in FIG. 7B, the acceleration obtained by synthesizing the accelerations in the three-axis directions of the present embodiment has a positive value and increases sharply at a certain time (1.5 seconds). This continues for a relatively long period (from 1.5 seconds to 5.0 seconds). Therefore, for example, by setting the threshold Th to about 0.10 G, it is possible to easily determine the acceleration change during the theft operation. Further, in the case of the acceleration pattern of the theft operation as shown in FIG. 7B, the state where the threshold value is 0.10 G or more is continued for about 3.5 seconds, so the acceleration change amount ΔVa is the threshold. What is necessary is just to adjust m of the continuous frequency which becomes more than value Th so that it may correspond to such duration.

  Next, a second embodiment of the present invention will be described. In the above embodiment, the theft determination is performed by comparing the acceleration vector change amount ΔVa and the posture change amount Δga with the threshold value Th independently, but in the second embodiment, the combination determination is performed. It is. FIG. 8 is a flowchart for explaining the operation of the second embodiment, and FIG. 8A shows an example in which the threshold pattern is changed.

  In the flow of FIG. 8, steps S201 to S204 and SS206 to S209 are the same as the flow of FIG. 6 described in the first embodiment, and thus description thereof is omitted here. The second embodiment includes a step (S205) of setting a threshold value corresponding to the posture change amount Δga. As shown in FIG. 8A, the threshold value holding unit 110 has an initial threshold value corresponding to the object in advance, and the threshold value is set according to the posture change amount Δga, for example, another pattern 1, It can be changed based on pattern 2 or pattern 3. Patterns 1, 2, and 3 are curves or straight lines that define the relationship between the posture change amount Δga and the threshold value Th, and each defines a different relationship. Can be prepared in the unit 110, select one of the patterns in accordance with the anti-theft application, and set a threshold value corresponding to the posture change amount calculated based on the selected pattern Can do. In another example, the threshold value holding unit 110 reduces the threshold value Th when the posture change amount Δga is larger than a reference value, and conversely, when the posture change amount Δga is smaller than the reference value. The threshold value Th can also be increased. Note that it is possible to select which pattern is selected from a plurality of patterns by user input.

  According to the second embodiment, the threshold value is dynamically changed according to the amount of change in the posture of the object. On the contrary, if the change in the posture of the object is small, it can be determined that the theft is based on the condition that a relatively large change in acceleration occurs.

  Next, a third embodiment of the present invention will be described. FIG. 9 is a block diagram showing the configuration of the theft determination unit 40A according to the third embodiment of the present invention. The same components as those in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted here. . In the third embodiment, the theft determination unit 40A further includes a direction determination unit 130 and an expected direction holding unit 140.

  The predicted direction holding unit 140 holds a reference direction Vp that predicts a direction in which an object will be moved when the object is stolen. For example, when a bicycle or a motorcycle is stolen, it is predicted that the bicycle or the motorcycle is moved within a certain angle range centering on the handle. Therefore, in the case of the motorcycle as shown in FIG. 13, the predicted direction holding unit 140 can hold the Y direction as the reference direction Vp. Further, the reference direction Vp held in the predicted direction holding unit 140 is constituted by a rewritable nonvolatile memory so as to be set according to the object to be monitored, and preferably, the reference direction is set via the user input unit 60. Vp can be set. The reference direction Vp may set not only the movement direction of the XY plane, the YZ plane, and the XZ plane, but also the movement direction of an XYZ three-dimensional space.

  The direction determination unit 130 compares the three-axis composite acceleration vector Vr (Vr0, Vr1,... Vrn) with the reference direction Vp, and if the composite acceleration vector Vr is within a certain range of the reference direction Vp, Is determined to have been stolen. FIG. 10 shows the relationship between the combined acceleration vector Vr and the expected direction Vp. The direction determining unit 130 determines whether or not all of Vr0, Vr1,... Vrn are within a certain range of the reference direction Vp, or the weighted average direction of Vr0, Vr1,. It is determined whether or not Vp is within a certain range, or whether or not the last change direction Vrn is within a certain range of the reference direction Vp. Note that + θ and −θ correspond to a certain range.

  Next, the operation of the antitheft device according to the third embodiment of the present invention will be described with reference to the flowchart of FIG. Steps S301 to S306 in the figure are the same as steps S101 to S106 in FIG. If the determination unit 100 determines that the magnitude of the acceleration vector change amount ΔVa or the posture change amount Δga is equal to or greater than the threshold value Th continuously m times (S306), the direction determination unit 130 then combines the three axes. The acceleration vector Vr is compared with the reference direction Vp held by the predicted direction holding unit 140 (S307), and it is determined whether or not the combined acceleration vector Vr is within the range of the reference direction Vp (S308). For example, when the reference direction Vp is equal to the Y-axis direction of the XY plane, a determination such as Vp−θ ≦ Vr ≦ Vp + θ is performed. This θ is set in advance according to the object, or arbitrarily set by the user.

  When it is determined that the resultant acceleration vector Vr is within a certain range of the reference direction Vp, the direction determination unit 130 determines that the object has been stolen (S309), and the alarm unit 50 receives an alarm based on this determination result. Is issued (S310). As described above, according to the third embodiment, it is possible to perform the more accurate theft determination by determining that the theft has been achieved when both the change amount and the change direction of the position or acceleration are satisfied. it can.

  Although the first to third embodiments have been described individually, it is obvious to those skilled in the art that the present invention may be appropriately combined with the first to third embodiments. The preferred embodiment of the present invention has been described in detail above, but the present invention is not limited to the specific embodiment, and various modifications can be made within the scope of the present invention described in the claims. Deformation / change is possible.

a: reference coordinate b: coordinate b ′ after posture change: coordinate after movement 10: anti-theft device 20: acceleration sensor 30: signal processing unit 40: anti-theft determination unit 50: alarm unit 60: user input unit 70: power supply Unit 80: Control unit 100: Determination unit 110: Threshold holding unit 120: Counter 130: Direction determination unit 140: Expected direction holding unit

Claims (18)

An anti-theft device that prevents theft of objects,
Detection means attached to the object and capable of detecting acceleration in the X, Y, and Z directions;
First calculation means for calculating an acceleration vector change amount of acceleration obtained by combining accelerations in the X, Y, and Z directions based on a detection result of the detection means;
Second calculation means for calculating a posture change amount of the object based on a detection result of the detection means;
Threshold setting means for setting the threshold;
The threshold value set by the threshold value setting means is compared with the acceleration vector change amount calculated by the first calculation means, and the object is stolen when the acceleration vector change amount is equal to or greater than the threshold value. Determination means for determining ,
The anti-theft device , wherein the threshold value setting means changes the threshold value according to the posture change amount calculated by the second calculation means . The threshold value setting unit holds a relationship between an attitude change amount and a threshold value in advance, and the threshold value setting unit changes the threshold value based on the previously held relationship. The anti-theft device described in 1. The threshold value setting means prepares a plurality of patterns that define the relationship between the posture change amount and the threshold value, and the threshold value setting means selects one of the patterns according to the anti-theft object. The antitheft device according to claim 1 or 2. 4. The determination unit according to claim 1, wherein the determination unit determines that the object has been stolen when an acceleration vector change amount or an attitude change amount measured at a plurality of time intervals is equal to or more than a threshold value continuously a plurality of times. The antitheft device according to one. The determination means further compares a reference direction in which a direction in which the object is moved when the object is stolen with a composite acceleration vector of the object, and when the composite acceleration vector is within a certain range of the reference direction, The antitheft device according to any one of claims 1 to 4, wherein the device is determined to have been stolen. The anti-theft device according to any one of claims 1 to 5, wherein the anti-theft device further includes a user input unit capable of setting a theft monitoring period, and the determination unit determines the theft during the theft monitoring period. apparatus. The anti-theft device according to any one of claims 1 to 6, wherein the threshold value of the threshold value setting means can be changed via a user input means. The anti-theft device further includes alarm means, which issues an alarm when it is determined that the theft is determined by the determining means, and transmits theft information regarding theft to the portable terminal using the communication means. The anti-theft device according to any one of claims 1 to 7, comprising either a device that issues a theft alarm via a mobile terminal or a device that displays alarm information on a mobile terminal. An anti-theft method for preventing theft of objects,
Attaching an acceleration sensor capable of detecting acceleration in the X, Y, and Z directions to an object to be monitored;
Setting a theft monitoring period for an object to be monitored;
A first calculation step of calculating an acceleration vector change amount of acceleration obtained by combining accelerations in the X, Y, and Z directions based on a detection result obtained from the acceleration sensor in the theft monitoring period;
A second calculation step of calculating a posture change amount of the object based on a detection result obtained from the acceleration sensor ;
Setting a threshold ;
Comparing the set threshold value with the acceleration vector change amount, and determining that the object has been stolen when the acceleration vector change amount is equal to or greater than the threshold value ;
The step of setting the threshold value is a theft prevention method in which the threshold value is changed according to the posture change amount calculated in the second calculating step . The theft prevention method according to claim 9, wherein the step of setting the threshold value changes the threshold value based on a relationship between a posture change amount held in advance and the threshold value. The step of setting the threshold value selects any one of a plurality of patterns that prescribes a relationship between a posture change amount and the threshold value according to an object to be protected against theft. Item 11. The antitheft method according to Item 9 or 10. The determination step determines that an object has been stolen when the acceleration vector change amount or the posture change amount measured at a plurality of time intervals is equal to or greater than a threshold value a plurality of times in succession. The theft prevention method as described in any one. The step of determining further compares a reference direction in which the direction in which the object is moved when the object is stolen and a combined acceleration vector of the object, and the combined acceleration vector is within a certain range of the reference direction; The theft prevention method according to any one of claims 9 to 12, wherein it is determined that an object has been stolen. An anti-theft program executed by an anti-theft device that attaches an acceleration sensor capable of detecting acceleration in the X, Y, and Z directions to an object to be monitored and prevents the theft of the object,
Setting a theft monitoring period for an object to be monitored;
Based on the detection result obtained from the acceleration sensor,
A first calculation step of calculating an acceleration vector change amount of acceleration obtained by combining accelerations in the X, Y, and Z directions based on a detection result obtained from the acceleration sensor in the theft monitoring period ;
A second calculation step of calculating a posture change amount of the object based on a detection result obtained from the acceleration sensor ;
Setting a threshold ;
Comparing the set threshold value with the acceleration vector change amount, and determining that the object has been stolen when the acceleration vector change amount is equal to or greater than the threshold value ;
The step of setting the threshold value is a theft prevention program for changing the threshold value according to the posture change amount calculated in the second calculating step . 15. The antitheft program according to claim 14, wherein the step of setting the threshold changes the threshold based on a relationship between a posture change amount and the threshold held in advance. The step of setting the threshold value selects any one of a plurality of patterns that prescribes a relationship between a posture change amount and the threshold value according to an object to be protected against theft. Item 16. The anti-theft program according to item 14 or 15. The theft according to any one of claims 14 to 16, wherein the determining step determines that the object has been stolen when the amount of change measured at a plurality of time intervals is equal to or greater than a threshold value a plurality of times. Prevention program. The step of determining further compares a reference direction in which the direction in which the object is moved when the object is stolen and a combined acceleration vector of the object, and the combined acceleration vector is within a certain range of the reference direction; The antitheft program according to any one of claims 14 to 17, which determines that an object has been stolen.

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