JP2004318299A - Crime prevention intruder detection system - Google Patents

Abstract

A security intruder detection system that can be applied to a relatively complicated corridor such as an art museum or an office building, or a room where various things are scattered.
A large number of Doppler radar sensors are arranged in an area where an intruder is to be detected, and an intruder is detected based on a correlation between a detection result by an (n−1) th sensor and a detection result by an nth sensor. Figure out the movement.
[Selection diagram] Fig. 4

Description

となるから、検知信号の周波数ｆ_ｄは図２のように変化する。
【００２３】
図中のＴ０で表されている時刻が、侵入者５がセンサ１１の正面前を通過した時刻である。従って、あるセンサの前を通過した時刻と別のセンサの前を通過した時刻の情報を元に、侵入者のおおよその動きを判断し、次に侵入者を検知すべきセンサを予測することで、検知精度を向上させることができる。
【００２４】
即ち、センサが設置されているエリアが、図３に示す廊下のような対象物の動きが一次元の定まった方向となる場所では、対象物がｎ―１番目のセンサ２を通過してからｔ_ｎ−１秒後、ｎ番目のセンサ１を通過してからｔ_ｎ秒後では、ｎ−１番目のセンサ２によるドップラー信号ｆ_ｄは、センサ２がある壁からの侵入者５の距離をｄ_ｎ−１、センサ１がある壁からの侵入者５の距離をｄ_ｎとすると、式（２）で与えられるように、
【００２５】
【数２】

であり、ｎ番目のセンサ１によるドップラー信号ｆ_ｄは、式（３）で与えられるように、
【００２６】
【数３】

となる。ｄ_ｎとｄ_ｎ−１の和は廊下の幅であり既知なので、未知数はｖとｄ_ｎ（又はｄ_ｎ−１）だけとなり、式（２）及び式（３）から対象物のおおよその位置を知ることが可能になる。
【００２７】
以上により、美術館やオフィスビルなどの比較的入り組んだ廊下や、様々なものが散在しているような室内に適用して好適な防犯用侵入者検知システムを実現することができる。
【００２８】
また、式（２）及び式（３）による計算を高速に行なうことにより、侵入者の位置をリアルタイムで検出することが可能になり、本発明の付帯的な第１の目的が達成される。
【００２９】
上述のように、検知したいエリアが美術館やオフィスビルの廊下などのように比較的入り組んだ構造をしている場合や、広い部屋でも障害物となるものが多数存在する部屋の場合、それぞれのレーダセンサが監視する領域は数メートル程度で十分である。従って、個々のレーダセンサには検知範囲が数ｍ程度の低性能のものを利用することが可能である。このレーダセンサとして、例えば、先に出願した特許願第２００２−１２５９１０号に記載の１チップで構成されるセンサを用いることができる。１チップ構成により、センサの単価が著しく抑えられるので、これを多数個配置したシステムの設置コストの上昇を抑えることができ、本発明の付帯的な第２の目的が達成される。
【００３０】
また、個々のセンサが侵入者を検出する範囲は狭いので、センサを設置した位置を前以て記憶しておくことにより、侵入者を検知しているセンサの位置情報からビルや建物内における侵入者のおおよその位置を検知することが可能となる。更に、この位置情報をある一定時間記憶しておく記憶手段を持たせ、侵入者の行動を一定時間観測することにより、侵入者の位置を追跡・分析することが可能となる。以上により、本発明の付帯的な第３の目的が達成される。
【００３１】
レーダセンサは、対象物からの反射信号を元に侵入者を検知する。従って、電波吸収体のような電磁波をあまり反射しない材質を纏っている侵入者を検知することは不可能である。そこで、侵入者からの反射信号を検知すると共に、近くに設置されている他のセンサからの電磁波を受信するように構成する。このように構成することで、電磁波の反射が得られない場合でも、他のセンサからの電磁波の受信の有無を検知することができる。従って、他のセンサからの電磁波が途切れるタイミングを検知することで、侵入者を検知することが可能になる。なお、反射体を設置し、反射体からのセンサ自身の電磁波を受信することで、同等の効果を得ることも可能である。以上により、本発明の付帯的な第４の目的が達成される。
【００３２】
また、入り口などに身分を照合する手段を設置し、この身分照合手段により入室を許可されていると判断された場合、その人は入室を許可されている者としてその後の動きを追跡し、身分照合手段により身分の照合をされなかった者を不審者として扱うことで、センサにより検知された侵入者を不審者か侵入を許可された者かを判断することが可能である。以上により、本発明の付帯的な第５の目的が達成される。
【００３３】
更に、壁や天井の材質に、電磁波の吸収性の高い材質を用いたり、壁紙用の接着剤に炭素紛などを混入することによって電磁波の吸収性を向上させることで、多重反射を抑制し、マルチパスによる誤検知を低減することが可能となり、本発明の付帯的な第６の目的が達成される。
【００３４】
【発明の実施の形態】
以下、本発明に係る防犯用侵入者検知システムを図面に示した発明の実施の形態を参照して更に詳細に説明する。
【００３５】
図４に示す、第１の実施形態によるセンサ設置例において、１，２，３は、廊下の壁に設置したそれぞれ、ｎ−１番目、ｎ番目、ｎ＋１番目のセンサ、６，７，８は、それぞれセンサ１，２，３の検知範囲を示す。
【００３６】
このような配置で、ｎ−１番目のセンサ２が侵入者５を検知し、次にｎ番目のセンサ１が侵入者５を検知したとする。このときセンサ１，２によって検知される侵入者５によるドップラー信号の周波数は図２のように変化する。図中のＴ０で表されている時刻が侵入者５が各センサの前を通過した時刻である。従って、ｎ−１番目のセンサ２の正面を通過する時刻とｎ番目のセンサ１の正面を通過する時刻を知ることができ、両時刻から侵入者５の動きを予測することができる。この予測に基づいて、次にｎ＋１番目のセンサ３が検知した侵入者が上記の侵入者と一致しているかが判断される。
【００３７】
図５に本実施形態の防犯用侵入者検知システムの構成を示す。図５において、１１ａは例えば入口に最も近い位置に配置したセンサ、１１ｐは例えば出口に最も近い位置に配置したセンサ（ｐ≧ｎ＋１）、３０は、各センサからの検知信号ｓ１，ｓ（ｎ−１），ｓｎ，ｓ（ｎ＋１），ｓｐを入力して、侵入者５に関する情報を出力端子３１に出力する信号処理装置（ＰＲＯＣ）である。
【００３８】
信号処理装置３０に入力される各センサからの検知信号ｓは、図２に示すドップラー周波数の信号に対して後述する処理を施して得られた対象物の移動速度を表す信号である。また、信号処理装置３０には各センサの位置情報が格納されており、信号処理装置３０は、各検知信号ｓ及びこれらの位置情報を用いて上記した侵入者５の動きの予測及び侵入者の一致の判断の処理を行なう。
【００３９】
このような信号処理装置３０の構成を図６に示す。図６において、３２は、各センサからの検知信号ｓの内、対象物検知の信号が含まれている検知信号ｓを選択する選択回路（ＳＥＬ）、３３は、選択回路３２が選択した検知信号ｓから、例えば式（２）及び式（３）に基づいて相互関係を算出し、侵入者５に関する情報（侵入者５の動きの予測、侵入者の一致の判断など）を出力する演算回路（ＣＡＬ）、３４は、演算回路３３が用いるセンサの位置情報や侵入者の通過時刻などの情報を蓄える記憶装置（ＭＥＭ）である。
【００４０】
続いて、図７にセンサの構成例を示す。マイクロ波又はミリ波の信号を発生する信号発生器１４により発生した信号は、増幅器１５、サーキュレータ１６を介し送受信アンテナ１９から電磁波となって送信される。
【００４１】
この信号は、対象物により反射され、その反射信号は再び送受信アンテナ１９により受信され、サーキュレータ１６を介して混合器１８に入力され、信号発生器１４により生成された元の信号と混合される。混合により、差の周波数成分を持つＩＦ信号が生成される。
【００４２】
送受信アンテナ１９により受信された反射信号は、対象物とセンサとの相対速度によるドップラー効果により僅かに周波数がシフトしているので、このＩＦ信号は、ドップラーシフトの大きさに依存した周波数を持つ。従って、このＩＦ信号をＦＦＴ（Ｆａｓｔ Ｆｏｕｌｉｅｒ Ｔｒａｎｆｏｍ）などの信号処理を行なうことにより、周波数が解析され、対象物の移動速度が検知される。センサからは、この移動速度を表す信号が検知信号ｓとして出力される。
【００４３】
本実施形態によれば、例えばｎ番目のセンサ１が侵入者を検知する範囲６は、センサ１からの最長距離が廊下の幅程度であり、廊下の奥行き方向から見たセンサ２との距離が３ｍ程度である。このように、個々のセンサが担当する検知範囲は比較的狭いので、センサ単体の検知性能は高い必要がない。従って、センサには、半導体の１チップによる簡易な構成のものを採用することが可能である。１チップ構成のセンサは安価であるので、システムの実用性を損なうことなく、美術館やオフィスビルなどの比較的入り組んだ廊下や、様々なものが散在しているような室内において、死角になるところを含めて要所要所に多数のセンサを配置することができる。
【００４４】
一方、本実施形態のシステムにおいては、信号処理装置３０が各センサの検知結果の相互関係に基づいて侵入者を検知するため、高精度な侵入者検知が可能である。例えば、対象物の動きが単一方向になる廊下のような検知エリアでは、図３に示すように、侵入者５がｎ−１番目のセンサ２とｎ番目のセンサ１によって検知される場合、上記の式（２）及び式（３）から、侵入者のおおよその位置を判別することが可能である。この判別の処理が信号処理装置３０によって行なわれる。
【００４５】
このように、侵入者を検知したセンサとセンサが設置されている位置情報を基に、不審者の位置を正確に把握することが可能であり、警備の安全性、正確性の向上することが可能である。
【００４６】
更に、これらの情報を信号処理装置３０の有する記憶装置３４に記録しておくことで、侵入者の行動パターンを追跡・分析することが可能であり、警備の安全性、正確性を向上することが可能である。
【００４７】
センサについては、ドップラーレーダ型のセンサの最も基本的な特性である速度検知のみを備えることで、侵入者のおおよその位置を判別することが可能であるため、個々のセンサに必要な信号処理を簡略化することができ、低コスト化が可能となる。
【００４８】
なお、より高精度の侵入者検知を行なうことを重視する場合には、センサに対して、対象物の速度検知の他、対象物の角度・距離などを検出する信号処理を加えることになる。
【００４９】
上記実施形態では、センサは検知エリアの両側に設置されているが、これを図８に示すように片側のみに設置し、ｎ−１番目のセンサ２とｎ番目のセンサ１の前を通過する時刻を元に侵入者の移動速度ｖを近似することで、同等の効果が得られる。この第２の本実施形態によれば、設置場所の構造上、片側だけにしかセンサを設置できない場合などに有効であり、さらには、天井などにセンサを設置する場合にも効果がある。
【００５０】
また、上記の第１，２の実施形態では、センサは目標物からの反射信号のみを検知していたが、例えば、図４におけるｎ−１番目のセンサ２が放射する信号をｎ番目のセンサ１が受信し、この信号が途切れるタイミングを検知することで、ｎ−１番目のセンサ２とｎ番目のセンサ１の間を侵入者が通過することを検知することも可能である。このような構成の第３の実施形態において、侵入者が電磁波の反射の少ない衣類を纏っていて反射信号が得られない場合でも、他のセンサからの受信信号を用いることにより、侵入者の検知が可能となる。
【００５１】
ここで、反射信号と他のセンサからの受信信号とを区別する方法を説明する。侵入者からの反射信号は、前記したようにドップラー効果により侵入者の移動速度に応じて周波数がシフトし、そのドップラー効果による周波数ｆ_ｄが式（１）によって示される。従って、例えば、センサの送信信号の周波数に２４ＧＨｚを用いた場合、目標物が１００ｋｍ／ｈという非常に高速で移動していても、周波数ｆ_ｄは約４．５ｋＨｚである。従って、侵入者による反射信号とｎ−１番目のセンサ２からの信号を区別するためには、ｎ−１番目のセンサ２とｎ番目のセンサ１の送信信号の周波数を１０ｋＨｚ程度以上離せば良い。これにより、反射信号と他のセンサからの受信信号とを区別することが可能になる。
【００５２】
また、上記では、ｎ−１番目のセンサ２とｎ番目のセンサ１に目標物からの反射信号も検知可能なセンサを用いたが、例えば図９に示すように、片側のセンサ１にのみこの機能を持たせ、反対側のセンサ２１には送信器の機能のみ、又は、受信器の機能のみを持たせることが可能である。この第４の実施形態により、システムを簡略化することが可能となる。
【００５３】
また、上記第１〜第４の実施形態では壁の両側にセンサを設置する場合を示したが、図１０に示すように、壁の片側のみセンサを設置し、代わりにｎ−１番目のセンサ２からの信号をｎ番目のセンサ１が受信できるように反射体２０を設置しても同等の効果が得られる。この第５の実施形態は、設置場所の構造上、片側だけにしかセンサを設置できない場合などに有効であり、更には、天井などにセンサを設置する場合にも効果がある。
【００５４】
なお、いずれの実施形態においても、壁や天井の材質に、電磁波の吸収性の高い材質を用いたり、壁紙用の接着剤に炭素紛などを混入することによって電磁波の吸収性を向上させることができる。それにより、多重反射を抑制し、マルチパスによる誤検知を低減することが可能となる。
【００５５】
また、入り口などに侵入者を識別する装置を設置し、この識別装置により入室を許されている者と判別された場合は、その後、入室を許可されている人として追跡を行なうことによって、センサにより検知した侵入者が不審者か入室を許可された人かを判別することが可能である。
【００５６】
更に、上述のセンサは、マイクロ波帯やミリ波帯などの電磁波を用いているので、壁紙程度の材質を透過することが可能である。従って、センサを壁紙などにより隠蔽することが可能であり、美観を保つと同時に、センサの存在が侵入者に感知されないようにすることが可能となる。
【００５７】
【発明の効果】
本発明によれば、複数のセンサによる検知結果を元に侵入者を検知するため、検知性能を向上することが可能である。それによって、美術館やオフィスビルなどの比較的入り組んだ廊下や、様々なものが散在しているような室内に適用して好適な防犯用侵入者検知システムを実現することができる。
【図面の簡単な説明】
【図１】センサと侵入者の位置関係を説明するための図。
【図２】センサにより検出されるドップラー周波数を説明するための曲線図。
【図３】ｎ番目及びｎ−１番目のセンサと侵入者の位置関係を説明するための図。
【図４】本発明に係る防犯用侵入者検知システムの第一の実施形態を説明するための配置図。
【図５】本発明に係る防犯用侵入者検知システムの第１の実施形態を説明するための構成図。
【図６】図５の防犯用侵入者検知システムで用いる信号処理装置の例を説明するための構成図。
【図７】図５の本発明の防犯用侵入者検知システムで用いるセンサの例を説明するための構成図。
【図８】本発明の第２の実施形態を説明するための配置図。
【図９】本発明の第４の実施形態を説明するための配置図。
【図１０】本発明の第５の実施形態を説明するための配置図。
【符号の説明】
１…ｎ番目のセンサ、２…ｎ−１番目のセンサ、３…ｎ＋１番目のセンサ、５…侵入者、６…ｎ番目のセンサの検知範囲、１１…センサ、１３…壁、１４…信号発生器、１５…増幅器、１６…サーキュレータ、１８…混合器、１９…送受信アンテナ、２０…反射体、２１…送信器又は受信器の機能のみを持つセンサ、３０…信号処理装置。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a crime prevention intruder detection system for monitoring an intruder or a suspicious person in a facility such as an art museum or an office building, or a general house.
[0002]
[Prior art]
As a security intruder detection system that detects an intruder or a suspicious person in an art museum, an office building, or a general house, there is a system that uses electromagnetic waves such as microwaves and millimeter waves. This system radiates electromagnetic waves to a monitored area (hereinafter referred to as “area”) where an intruder is to be detected. If there is an intruder in the detection area, this electromagnetic wave is reflected by the intruder. By receiving the reflected signal, the presence or absence of an intruder in the detection area is determined. An example of a detection system employing an FM-CM radar in which an electromagnetic wave is a frequency modulated wave is disclosed in, for example, Patent Document 1.
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-3478
[Problems to be solved by the invention]
However, the above-described system according to the prior art is suitable for detecting a relatively large space with good visibility, but is relatively suitable for detecting a relatively narrow space such as a corridor such as an art museum or an office building. In a room where objects are scattered, an area where electromagnetic waves cannot reach occurs, and a blind spot occurs. Therefore, if the intruder enters the blind spot, it is naturally impossible to detect the intruder. In order to cover this blind spot, it is necessary to install many intruder detection sensors.
[0005]
In general, a high-performance radar sensor that detects a wide range is used as a sensor, but such a sensor is expensive. Therefore, a system in which many expensive sensors are installed has to be expensive.
[0006]
On the other hand, in order to reduce the cost of the system, if the above sensor is installed only in a part of the building, when the intruder moves out of the detection range, it is necessary to determine where the intruder is in the building. Is difficult.
[0007]
A radar sensor generally used for intruder detection detects an object by emitting an electromagnetic wave and receiving a reflected signal of the electromagnetic wave reflected by the object. Therefore, when an intruder is wearing a material that absorbs electromagnetic waves, such as a radio wave absorber, it is difficult to detect the intruder because the electromagnetic waves are hardly reflected.
[0008]
Furthermore, it is conceivable that a person who is permitted to enter is within the detection range of the security intruder detection system, but it is difficult to determine whether the person detected by the sensor is a suspicious person or a person who is permitted to enter. It is difficult.
[0009]
Further, since these sensors are generally installed with their sensor portions exposed, there is a problem that an intruder easily notices the sensors and a problem that the appearance is impaired.
[0010]
Furthermore, in a relatively narrow and complicated place such as a corridor such as an art museum or an office building, or in a room where various things are scattered, a security device suitable for detecting a wide area as described above is used. In such a case, there is a problem in that electromagnetic waves are reflected by an object placed in a wall or a room to cause a multipath, and a ghost that detects an object that should not exist is generated.
[0011]
In view of the above problems, a main object of the present invention is to provide a security intruder detection system that can be applied to relatively intricate corridors such as museums and office buildings, and indoors where various things are scattered. To provide.
[0012]
A first object of the present invention is to detect a position of an intruder in real time even in a relatively complicated corridor such as an art museum or an office building, or in a room where various things are scattered. It is to provide a simple security intruder detection system.
[0013]
A second object of the present invention is to suppress an increase in installation cost in a system in which a large number of intruder detection sensors are arranged.
[0014]
A third object of the present invention is to provide a security intruder detection system capable of tracking and analyzing the behavior of a suspicious individual.
[0015]
A fourth object of the present invention is to provide a security intruder detection system capable of detecting an intruder even when the intruder is wearing clothes absorbing electromagnetic waves.
[0016]
A fifth object of the present invention is to provide a system that can easily determine whether a detected intruder is permitted to enter.
[0017]
A sixth object of the present invention is to provide a security intrusion with less erroneous detection due to the effect of multipath even in a relatively complicated corridor such as an art museum or an office building, or in a room where various things are scattered. It is to provide a person detection system.
[0018]
[Means for Solving the Problems]
The security intruder detection system of the present invention for achieving the above main object has a number of sensors arranged in an area where an intruder is desired to be detected, and utilizes a mutual relation of signals detected by the respective sensors to detect an object. Detection is performed. As the sensor, a radar sensor that transmits an electromagnetic wave having a frequency ranging from a microwave band to a millimeter wave band and detects a target object by receiving a reflected wave from the target object is used.
[0019]
Now, when an intruder is detected by one sensor, based on information such as the moving speed and distance of the intruder detected by that sensor and information such as the moving speed and distance detected by another sensor, Figure out the movement. Multiple sensors that detect intruders may detect the intruder at the same time by overlapping their detection ranges.However, each monitors a different detection range, and the time when each sensor detects the intruder and the sensor The intruder may be monitored based on information on the position where the is installed. By doing so, the intruder is determined based on the detection results of the plurality of sensors, and the detection accuracy can be improved.
[0020]
For example, a Doppler radar type sensor is used as a radar sensor for detecting an intruder. The Doppler radar type sensor emits an electromagnetic wave by a transmitting antenna and receives a reflected signal from an object. At this time, when there is a relative speed between the radar sensor and the object, the frequency of the reflected signal slightly shifts due to the Doppler effect. By comparing the frequency of the received reflection signal with the frequency of the original transmission signal, the moving speed of the target object can be detected.
[0021]
In the case of a Doppler radar type sensor, the most easily available information is the moving speed of the object. For example, as shown in FIG. 1, when the front of the sensor 11 installed in the wall 13 intruder 5 has passed, the frequency f _d of Doppler frequency or the detection signal is detected, the speed of the intruder 5 v, Assuming that the angle is θ, the frequency of the radiated electromagnetic wave is f ₀ , and c is the speed of light, as given by equation (1),
[0022]
(Equation 1)

Since the frequency f _d of the detection signal changes as shown in FIG.
[0023]
The time represented by T0 in the figure is the time when the intruder 5 passes in front of the sensor 11. Therefore, based on the information of the time at which the intruder passed in front of one sensor and the time of passing in front of another sensor, the approximate movement of the intruder is determined, and the next sensor to detect the intruder is predicted. , Detection accuracy can be improved.
[0024]
That is, in an area where the sensors are installed, such as a corridor shown in FIG. 3, where the movement of the object is in a one-dimensional fixed direction, the object passes through the (n−1) th sensor 2 After t _n-1 seconds and after passing t _n seconds after passing through the n-th sensor 1, the Doppler signal f _d from the (n-1) -th sensor 2 indicates the distance of the intruder 5 from the wall where the sensor 2 is located. Assuming that d _n−1 and the distance of the intruder 5 from the wall where the sensor 1 is located is d _n , as given by Expression (2),
[0025]
(Equation 2)

And the Doppler signal f _{d from} the nth sensor 1 is given by equation (3):
[0026]
[Equation 3]

It becomes. the sum of d _n and _{d n-1} is known is the width of the corridor, unknowns v and _{d n} (or _{d n-1)} only and becomes an approximate position of the object from the formula (2) and (3) It becomes possible to know.
[0027]
As described above, a suitable security intruder detection system that can be applied to a relatively complicated corridor such as an art museum or an office building or a room where various objects are scattered can be realized.
[0028]
Further, by performing calculations at high speed by the equations (2) and (3), the position of the intruder can be detected in real time, and the supplementary first object of the present invention is achieved.
[0029]
As described above, if the area to be detected has a relatively complicated structure such as a corridor in an art museum or office building, or if there is a large room with many obstacles, A few meters is sufficient for the area monitored by the sensor. Therefore, it is possible to use a low performance sensor having a detection range of about several meters for each radar sensor. As this radar sensor, for example, a sensor composed of one chip described in Japanese Patent Application No. 2002-125910 filed earlier can be used. With the one-chip configuration, the unit price of the sensor is significantly reduced, so that it is possible to suppress an increase in the installation cost of a system in which a large number of sensors are arranged, and the supplementary second object of the present invention is achieved.
[0030]
In addition, since the range in which each sensor detects an intruder is small, the position where the sensor is installed is stored in advance so that intrusion in a building or building can be determined based on the position information of the sensor that detects the intruder. It is possible to detect the approximate position of the person. Further, by providing a storage means for storing this position information for a certain period of time and observing the intruder's behavior for a certain period of time, the position of the intruder can be tracked and analyzed. As described above, the supplementary third object of the present invention is achieved.
[0031]
The radar sensor detects an intruder based on a reflected signal from an object. Therefore, it is impossible to detect an intruder wearing a material that does not reflect much electromagnetic waves, such as a radio wave absorber. Therefore, a configuration is adopted in which a reflected signal from an intruder is detected and an electromagnetic wave is received from another sensor installed nearby. With this configuration, it is possible to detect the presence or absence of reception of an electromagnetic wave from another sensor even when reflection of the electromagnetic wave cannot be obtained. Therefore, an intruder can be detected by detecting the timing when the electromagnetic wave from another sensor is interrupted. The same effect can be obtained by installing a reflector and receiving the electromagnetic wave of the sensor itself from the reflector. Thus, the supplementary fourth object of the present invention is achieved.
[0032]
In addition, a means for verifying the identity is installed at the entrance, etc., and if it is determined that the person is permitted to enter the room by this identity verification means, the person will follow the subsequent movement as a person who is permitted to enter the room, By treating a person whose identity has not been verified by the verification means as a suspicious person, it is possible to determine whether the intruder detected by the sensor is a suspicious person or a person permitted to enter. Thus, the incidental fifth object of the present invention is achieved.
[0033]
Furthermore, the material of the wall and ceiling is made of a material with high electromagnetic wave absorption, or by mixing carbon powder etc. into the adhesive for wallpaper, the electromagnetic wave absorption is improved, thereby suppressing multiple reflections. False detection due to multipath can be reduced, and the supplementary sixth object of the present invention is achieved.
[0034]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a security intruder detection system according to the present invention will be described in more detail with reference to embodiments of the invention shown in the drawings.
[0035]
In the sensor installation example according to the first embodiment shown in FIG. 4, 1, 2 and 3 are the (n−1) th, nth and (n + 1) th sensors installed on the wall of the corridor, and 6, 7, and 8 are Shows the detection ranges of the sensors 1, 2, and 3, respectively.
[0036]
In such an arrangement, it is assumed that the (n-1) th sensor 2 detects the intruder 5, and then the nth sensor 1 detects the intruder 5. At this time, the frequency of the Doppler signal by the intruder 5 detected by the sensors 1 and 2 changes as shown in FIG. The time represented by T0 in the figure is the time when the intruder 5 passes in front of each sensor. Therefore, it is possible to know the time of passing the front of the (n−1) th sensor 2 and the time of passing the front of the nth sensor 1, and it is possible to predict the movement of the intruder 5 from both times. Based on this prediction, it is determined whether the intruder detected by the (n + 1) th sensor 3 matches the intruder.
[0037]
FIG. 5 shows the configuration of the security intruder detection system of the present embodiment. In FIG. 5, 11a is, for example, a sensor arranged at a position closest to the entrance, 11p is, for example, a sensor arranged at a position closest to the exit (p ≧ n + 1), and 30 is a detection signal s1, s (n− 1), a signal processing device (PROC) that inputs sn, s (n + 1), and sp and outputs information about the intruder 5 to an output terminal 31.
[0038]
The detection signal s from each sensor input to the signal processing device 30 is a signal representing the moving speed of the target obtained by performing a process described later on the Doppler frequency signal shown in FIG. In addition, the signal processing device 30 stores position information of each sensor, and the signal processing device 30 predicts the movement of the intruder 5 and detects the intruder using the detection signals s and the position information. A process for determining a match is performed.
[0039]
FIG. 6 shows the configuration of such a signal processing device 30. In FIG. 6, reference numeral 32 denotes a selection circuit (SEL) for selecting a detection signal s including a target object detection signal from detection signals s from the sensors, and 33 denotes a detection signal selected by the selection circuit 32. An arithmetic circuit (e.g., calculates a correlation from s based on Equations (2) and (3), for example, and outputs information about the intruder 5 (for example, predicting the movement of the intruder 5 and determining whether the intruder 5 matches) CAL) and 34 are storage devices (MEM) for storing information such as the position information of sensors used by the arithmetic circuit 33 and the passing time of intruders.
[0040]
Subsequently, FIG. 7 shows a configuration example of the sensor. The signal generated by the signal generator 14 that generates a microwave or millimeter wave signal is transmitted as an electromagnetic wave from the transmission / reception antenna 19 via the amplifier 15 and the circulator 16.
[0041]
This signal is reflected by the object, and the reflected signal is received again by the transmission / reception antenna 19, input to the mixer 18 via the circulator 16, and mixed with the original signal generated by the signal generator 14. The mixing generates an IF signal having a difference frequency component.
[0042]
Since the frequency of the reflected signal received by the transmitting / receiving antenna 19 is slightly shifted due to the Doppler effect due to the relative speed between the object and the sensor, the IF signal has a frequency depending on the magnitude of the Doppler shift. Therefore, by performing signal processing such as FFT (Fast Foiler Transform) on the IF signal, the frequency is analyzed, and the moving speed of the object is detected. A signal representing the moving speed is output from the sensor as a detection signal s.
[0043]
According to the present embodiment, for example, in the range 6 in which the n-th sensor 1 detects an intruder, the longest distance from the sensor 1 is about the width of the corridor, and the distance from the sensor 2 as viewed from the depth direction of the corridor is It is about 3 m. As described above, since the detection range assigned to each sensor is relatively narrow, the detection performance of the sensor alone does not need to be high. Therefore, it is possible to employ a sensor having a simple configuration using one semiconductor chip. Because the one-chip sensor is inexpensive, blind spots can be found in relatively intricate corridors such as museums and office buildings and indoors where various things are scattered without impairing the practicality of the system. A large number of sensors can be arranged at important places including the above.
[0044]
On the other hand, in the system of the present embodiment, since the signal processing device 30 detects an intruder based on the correlation between the detection results of the sensors, highly accurate intruder detection is possible. For example, in a detection area such as a corridor where the movement of the target object is in a single direction, as shown in FIG. 3, when the intruder 5 is detected by the (n-1) th sensor 2 and the nth sensor 1, From the above equations (2) and (3), it is possible to determine the approximate position of the intruder. This determination processing is performed by the signal processing device 30.
[0045]
In this way, it is possible to accurately grasp the position of the suspicious individual based on the sensor that detected the intruder and the position information where the sensor is installed, and it is possible to improve security and accuracy of security. It is possible.
[0046]
Further, by recording such information in the storage device 34 of the signal processing device 30, it is possible to track and analyze the intruder's behavior pattern, thereby improving the security and accuracy of security. Is possible.
[0047]
As for sensors, by providing only the speed detection, which is the most basic characteristic of Doppler radar type sensors, it is possible to determine the approximate position of the intruder, so the signal processing required for each sensor is performed It can be simplified and cost can be reduced.
[0048]
When importance is placed on performing higher-precision intruder detection, signal processing for detecting the angle and distance of the target object is performed on the sensor in addition to detecting the speed of the target object.
[0049]
In the above embodiment, the sensors are installed on both sides of the detection area, but they are installed only on one side as shown in FIG. 8, and pass in front of the (n-1) th sensor 2 and the nth sensor 1. By approximating the moving speed v of the intruder based on the time, the same effect can be obtained. The second embodiment is effective when the sensor can be installed on only one side due to the structure of the installation location, and is also effective when the sensor is installed on a ceiling or the like.
[0050]
In the first and second embodiments, the sensor detects only the reflected signal from the target. For example, the signal emitted from the (n-1) th sensor 2 in FIG. By detecting the timing when this signal is received and this signal is interrupted, it is also possible to detect that an intruder passes between the (n−1) th sensor 2 and the nth sensor 1. In the third embodiment having such a configuration, even when an intruder is wearing clothing with low electromagnetic wave reflection and a reflected signal cannot be obtained, detection of the intruder is performed by using a reception signal from another sensor. Becomes possible.
[0051]
Here, a method of distinguishing a reflected signal from a received signal from another sensor will be described. Reflected signal from an intruder, shifts the frequency according to the moving speed of the intruder by Doppler effect as described above, the frequency f _d by the Doppler effect shown by the formula (1). Thus, for example, the case of using the 24GHz frequency of the transmission signal of the sensor, even if the target object is not moving at a very high speed of 100km / h, the frequency _{f d} is about 4.5 kHz. Therefore, in order to distinguish the signal reflected by the intruder from the signal from the (n-1) th sensor 2, the frequencies of the transmission signals of the (n-1) th sensor 2 and the nth sensor 1 should be separated by about 10 kHz or more. . This makes it possible to distinguish between a reflected signal and a received signal from another sensor.
[0052]
Further, in the above, a sensor capable of detecting a reflection signal from a target is used as the (n-1) th sensor 2 and the nth sensor 1, but for example, as shown in FIG. The sensor 21 on the opposite side can have only a function of a transmitter or only a function of a receiver. According to the fourth embodiment, the system can be simplified.
[0053]
In the first to fourth embodiments, the case where the sensors are installed on both sides of the wall is shown. However, as shown in FIG. 10, the sensors are installed only on one side of the wall, and the (n-1) th sensor is used instead. Even if the reflector 20 is provided so that the n-th sensor 1 can receive the signal from the second sensor 1, the same effect can be obtained. The fifth embodiment is effective when the sensor can be installed on only one side due to the structure of the installation place, and is also effective when the sensor is installed on a ceiling or the like.
[0054]
In any of the embodiments, the material of the wall or the ceiling may be made of a material having high electromagnetic wave absorption, or the adhesive of the wallpaper may be mixed with carbon powder or the like to improve the electromagnetic wave absorption. it can. This makes it possible to suppress multiple reflections and reduce erroneous detection due to multipath.
[0055]
In addition, a device for identifying an intruder is installed at the entrance, etc., and if it is determined that the person is allowed to enter the room by this identification device, then the person is tracked as a person who is allowed to enter the room, It is possible to determine whether the detected intruder is a suspicious individual or a person who is permitted to enter the room.
[0056]
Further, since the above-described sensor uses electromagnetic waves in a microwave band, a millimeter wave band, or the like, it is possible to transmit a material such as a wallpaper. Therefore, it is possible to cover the sensor with wallpaper or the like, and it is possible to maintain the appearance and prevent the intruder from detecting the presence of the sensor.
[0057]
【The invention's effect】
According to the present invention, an intruder is detected based on detection results by a plurality of sensors, so that detection performance can be improved. Thus, a suitable security intruder detection system that can be applied to a relatively complicated corridor such as an art museum or an office building or a room where various things are scattered can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a positional relationship between a sensor and an intruder.
FIG. 2 is a curve diagram for explaining a Doppler frequency detected by a sensor.
FIG. 3 is a diagram for explaining a positional relationship between an nth and (n−1) th sensors and an intruder.
FIG. 4 is a layout diagram for explaining a first embodiment of a security intruder detection system according to the present invention.
FIG. 5 is a configuration diagram illustrating a first embodiment of a security intruder detection system according to the present invention.
FIG. 6 is a configuration diagram illustrating an example of a signal processing device used in the security intruder detection system of FIG. 5;
FIG. 7 is a configuration diagram illustrating an example of a sensor used in the security intruder detection system of the present invention in FIG. 5;
FIG. 8 is a layout diagram for explaining a second embodiment of the present invention.
FIG. 9 is a layout diagram for explaining a fourth embodiment of the present invention.
FIG. 10 is a layout diagram for explaining a fifth embodiment of the present invention.
[Explanation of symbols]
1 ... nth sensor, 2 ... n-1st sensor, 3 ... n + 1th sensor, 5 ... intruder, 6 ... detection range of nth sensor, 11 ... sensor, 13 ... wall, 14 ... signal generation 15: amplifier, 16: circulator, 18: mixer, 19: transmitting / receiving antenna, 20: reflector, 21: sensor having only a transmitter or receiver function, 30: signal processing device.

Claims (10)

A plurality of sensors for detecting moving objects disposed in a monitoring area for detecting intruders;
A signal processing device that receives a detection signal output from the plurality of sensors and detects an intruder by using a correlation between detection signals from at least two sensors of the plurality of sensors,
Each of the sensors emits an electromagnetic wave having a frequency ranging from a microwave band to a millimeter wave band, and the electromagnetic wave receives the reflected signal reflected by the object, detects the object, and detects the object. Is output as the detection signal. The detection signal output by the sensor is indicative of the moving speed of the object, and the signal processing device is configured to determine a correlation between the moving speeds of the object detected by at least two of the sensors. The security intruder detection system according to claim 1, wherein an approximate position of the intruder is specified from the following. At least one of the plurality of sensors receives a reflected signal from the object and outputs a detection signal, and receives a signal emitted by another sensor and outputs a reception signal indicating the presence or absence of the signal. Output, the signal processing device detects that the signal emitted by the other sensor is interrupted from the input received signal, thereby detecting that the intruder has passed the sensor that outputs the received signal. The security intruder detection system according to claim 1, wherein At least one of the plurality of sensors receives a reflected signal from the object and outputs a detection signal, and a signal radiated by the at least one sensor is reflected by a reflector installed in advance. The signal processing device receives the received signal and outputs a reception signal indicating the presence or absence of the signal, and the signal processing device detects a time at which the signal emitted by the sensor is interrupted from the input reception signal, thereby enabling the intruder to receive the reception signal. The intruder detection system for crime prevention according to claim 1, wherein the system detects that the vehicle has passed a sensor that outputs a signal. The security device according to claim 1, wherein the signal processing device obtains position information of the intruder based on information of a position where a sensor that outputs a detection signal when detecting the intruder is installed. For intruder detection system. The signal processing device has a storage unit that stores information of a position where a sensor that outputs a detection signal when detecting an intruder and information of a time at which the intruder is detected,
It has a function of tracking or analyzing the movement of the intruder from information on the position where the sensor that outputs the detection signal when detecting the intruder and information on the time when the intruder was detected. The security intruder detection system according to claim 1, wherein: An identification means for determining whether or not the intruder is permitted to intrude is installed in or near the monitoring area for detecting the intruder, and the signal processing device transmits information from the identification means to the intruder. 2. The security intruder detection system according to claim 1, wherein the system detects whether the entered and detected intruder is authorized. The security intruder detection system according to claim 1, wherein the plurality of sensors are concealed by a material that transmits electromagnetic waves, such as wallpaper. The material according to claim 1, wherein a material that absorbs electromagnetic waves is used for at least one of a ceiling, a floor, a wall, a wallpaper, and an adhesive for attaching the wallpaper to the monitoring area for detecting the intruder. Security intruder detection system. A plurality of sensors forming a detection range for detecting a moving object by radiating electromagnetic waves of a frequency ranging from a microwave band to a millimeter wave band,
When an object passes through at least two detection ranges among a plurality of detection ranges obtained when the plurality of sensors are arranged in a monitoring area for detecting an intruder, a signal from the sensor having the two detection ranges is obtained. A signal processing device that performs a process of detecting the target object as an intruder using the detection signal,
Each of the sensors detects a target by receiving a reflected signal of the electromagnetic wave reflected by the target, and outputs a detection result as the detection signal. .

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