JP2961945B2 - Magnetometer - Google Patents
MagnetometerInfo
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- JP2961945B2 JP2961945B2 JP3117581A JP11758191A JP2961945B2 JP 2961945 B2 JP2961945 B2 JP 2961945B2 JP 3117581 A JP3117581 A JP 3117581A JP 11758191 A JP11758191 A JP 11758191A JP 2961945 B2 JP2961945 B2 JP 2961945B2
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- magnetic
- equation
- magnetic field
- matrix
- components
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- Measuring Magnetic Variables (AREA)
- Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、磁気測定に関し、さら
に詳しくいえば磁気双極子の位置と磁気モーメントを求
める装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to magnetic measurement, and more particularly to an apparatus for determining the position and magnetic moment of a magnetic dipole.
【０００２】[0002]
【従来の技術】磁気双極子の位置と磁気モーメントを求
める必要性は高く、例えば心臓磁界や脳磁界の測定等に
も利用されるため、従来よりこれらの計測について種々
の研究がされてきた。そして、例えば磁界の１成分と磁
界傾度５成分を測定して磁気モーメント等を求める方法
(Advanced Superconducting Gradiometer/Magnetomoter
Arrays and a Novel Signal Processing Technique ，I
EEE Transaction onMagnetic VOL.MAG-11 No.2(March
1975))や、磁界の絶対値と磁界傾度５成分を測定して磁
気モーメント等を求める方法（磁界傾度ならびに全磁界
計測による自制物***置の精密探知法、防衛大学校、理
工学研究報告、第１８巻、第２号）等が提案されてお
り、これらの方法を利用する発明も存在する。2. Description of the Related Art The need to determine the position and magnetic moment of a magnetic dipole is high, and it is used for, for example, the measurement of a cardiac magnetic field or a cerebral magnetic field. Then, for example, a method of measuring one component of a magnetic field and five components of a magnetic field gradient to obtain a magnetic moment or the like.
(Advanced Superconducting Gradiometer / Magnetomoter
Arrays and a Novel Signal Processing Technique, I
EEE Transaction onMagnetic VOL.MAG-11 No.2 (March
1975)) and a method of measuring the absolute value of the magnetic field and the five components of the magnetic field gradient to determine the magnetic moment, etc. (Precise detection method of the self-controlled object position by measuring the magnetic field gradient and the total magnetic field, Defense College, Science and Engineering Research Report, 18, No. 2) and the like, and there are inventions utilizing these methods.
【０００３】[0003]
【発明が解決しようとする課題】しかし、上記の方法で
磁気双極子の位置と磁気モーメントが求めようとする
と、同時に他の不要な解（真の解に対する偽の解）も導
出されてしまい、従って、求まった解について真偽判定
をしなければならないという問題がある。つまり、上記
した従来の手法を利用した発明では真偽判定の煩雑な作
業が必要となるのである。また、真偽判定をしても、い
ずれの解が真なのか判定できない場合も生じ得る。However, if the position and magnetic moment of the magnetic dipole are determined by the above method, other unnecessary solutions (fake solutions to true solutions) are derived at the same time. Therefore, there is a problem that it is necessary to judge the obtained solution. That is, in the invention using the above-described conventional method, a complicated operation of authenticity determination is required. In addition, there may be cases where it is not possible to determine which solution is true even if the truth is determined.
【０００４】本発明はかかる点に鑑みたもので、煩雑な
真偽判定を不要にし簡単な処理で磁性体の位置とその磁
気モーメントを求めることの出来る磁気測定器を提供す
ることを目的とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a magnetometer capable of determining the position of a magnetic body and its magnetic moment by a simple process without the need for complicated authenticity determination. .
【０００５】[0005]
【課題を解決するための手段】本発明は、上記の目的を
達成するため、互いに直交する３軸方向の磁界成分を検
出する第一の測定手段と、この磁界成分についての各軸
方向の磁界傾度のうち、互いに独立な５成分を検出する
第二の測定手段と、上記第一と第二の測定手段の結果を
基にして数値計算をし磁性体の位置と磁性体の磁気モー
メントを求める制御手段とで構成されている。In order to achieve the above object, the present invention provides a first measuring means for detecting magnetic field components in three axial directions orthogonal to each other, and a magnetic field in each axial direction for the magnetic field components. Among the gradients, a second measuring means for detecting five mutually independent components and a numerical calculation based on the results of the first and second measuring means to obtain the position of the magnetic body and the magnetic moment of the magnetic body And control means.
【０００６】[0006]
【作用】第一の測定手段は、互いに直交する３軸方向の
磁界成分（直交する軸をｘ，ｙ，ｚとすると各軸方向成
分Ｈx ，Ｈy ，Ｈz ）を検出する。また第二の測定手段
は、上記磁界成分Ｈx ，Ｈy ，Ｈz の各軸方向の磁界傾
度のうち互いに独立な５成分(例えば∂Ｈx ／∂ｘ，∂
Ｈy ／∂ｘ，∂Ｈz ／∂ｘ，∂Ｈy ／∂ｙ，∂Ｈz ／∂
ｙ）を検出する。そして、制御手段は、この８個のデー
タを基にして後述する演算をして磁性体の位置と磁気モ
ーメントを求める。The first measuring means detects magnetic field components in three mutually orthogonal directions (assuming orthogonal axes are x, y and z, respective axial components H x , H y and H z ). In addition, the second measuring means includes five independent components (for example, {H x / ∂x, ∂}) of the magnetic field gradients in the respective axial directions of the magnetic field components H x , H y , and H z.
H y / ∂x, ∂H z / ∂x, ∂H y / ∂y, ∂H z / ∂
y) is detected. Then, the control means calculates the position and magnetic moment of the magnetic body by performing a calculation described later based on the eight data.
【０００７】以下、制御手段の演算内容を説明するた
め、理論的内容から説明を始める（尚、表記の都合上、
ベクトル量は ’記号を付けることにする）。直角座標
観測系の原点位置Ｏに磁気双極子があり、磁界の観測点
をＰとする（図４参照）。そして、磁気双極子の磁気モ
ーメントをＭ’＝（Ｍx , Ｍy ，Ｍz ）、観測点Ｐの位
置ベクトルをｒ’＝（ｘ，ｙ，ｚ）、観測点Ｐの磁位を
Ｕ、観測点Ｐの磁界をＨ’＝（Ｈx , Ｈy ，Ｈz ）とす
ると、これらの関係は Ｕ＝（Ｍ’・ｒ’）／ｒ （式１） Ｈ’＝ｇｒａｄＵ （式２）である。 ここで、行列ＡをHereinafter, in order to explain the operation contents of the control means, the explanation will be started from theoretical contents (for convenience of notation,
The vector quantity will be marked with a '). There is a magnetic dipole at the origin position O of the rectangular coordinate observation system, and the observation point of the magnetic field is P (see FIG. 4). The magnetic dipole of magnetic moment M '= (M x, M y, M z), the position vector of the observation point P r' = (x, y , z), the magnetic potential of the observation point P U, Assuming that the magnetic field at the observation point P is H ′ = (H x , H y , H z ), these relations are as follows: U = (M ′ · r ′) / r (Equation 1) H ′ = gradU (Equation 2) is there. Here, matrix A
【０００８】[0008]
【数１】 (Equation 1)
【０００９】（式３）と定義すると（尚、ｒ＝｜ｒ’｜
とした）磁界Ｈ’と磁気モーメントＭ’の関係はWhen defined as (Equation 3) (where r = | r '|
The relationship between the magnetic field H ′ and the magnetic moment M ′ is
【００１０】[0010]
【数２】 (Equation 2)
【００１１】（式４）となる。また、磁気双極子に対す
るオイラーの式、つまり(Equation 4) Also, Euler's equation for magnetic dipoles,
【００１２】[0012]
【数３】 （式５）より(Equation 3) From (Equation 5)
【００１３】[0013]
【数４】 (Equation 4)
【００１４】（式６）が成立する。ここで、行列Ｂは、(Equation 6) holds. Here, the matrix B is
【００１５】[0015]
【数５】 (Equation 5)
【００１６】（式７）である。従って、（式４）と（式
６）を解くことによりＭ’とｒ’は次のように求まる。(Equation 7). Therefore, M 'and r' are obtained as follows by solving (Equation 4) and (Equation 6).
【００１７】[0017]
【数６】 （式８）(Equation 6) (Equation 8)
【００１８】[0018]
【数７】 (Equation 7)
【００１９】（式９）ただし、静磁界においては、ｒｏ
ｔＨ’＝０ であるから(Equation 9) However, in a static magnetic field, ro
Since tH '= 0
【００２０】[0020]
【数８】 (Equation 8)
【００２１】（式１０）が成立する。また、∇2 Ｈ’＝
0 であるので(Equation 10) is established. Also, ∇ 2 H ′ =
Because it is 0
【００２２】[0022]
【数９】 (Equation 9)
【００２３】（式１１）が成立する。この（式１０）
（式１１）の関係を考慮すると、（式７）で与えられる
行列Ｂの９個の要素のうち、５個の要素のみが独立であ
ることがわかる。つまり、例えば(Equation 11) is established. This (Equation 10)
Considering the relationship of (Equation 11), it can be seen that out of the nine elements of the matrix B given by (Equation 7), only five elements are independent. So, for example,
【００２４】[0024]
【数１０】 (Equation 10)
【００２５】の５要素についてその値が分かり、かつＨ
x ，Ｈy，Ｈz の３成分の値が分かれば、（式８）と
（式９）から磁性体の位置と磁気モーメントの値が特定
できることになる。本発明は、以上の関係を利用したも
のである。すなわち、制御手段は、第二の測定手段によ
る∂Ｈx ／∂ｘ，∂Ｈy ／∂ｘ，∂Ｈz ／∂ｘ，∂Ｈy
／∂ｙ，∂Ｈz／∂ｙの各値を（式７）に代入して行列
Ｂの各要素を求め(なお（式１０）も利用する）、周知
の方法で行列Ｂの逆行列Ｂ-1の各要素を求める。そし
て、Ｂ-1の各要素値と第一の測定手段によるＨx ，
Ｈy ，Ｈz の値を（式９）に代入して磁性体の位置
（ｘ，ｙ，ｚ）を求める。次に、制御手段は、いま求め
た（ｘ，ｙ，ｚ）の値からｒを決定し、（式３）を利用
して行列Ａの各要素を求める。そして、周知の方法で行
列Ａの逆行列Ａ-1の各要素を求め、このＡ-1と第一の測
定手段によるＨx ，Ｈy ，Ｈz の値を（式８）に代入し
て磁気モーメント（Ｍx ，Ｍy ，Ｍz ）を求める。The values of the five elements are known and H
x, H y, knowing the value of the three components of H z, will be able to identify the values of the position and the magnetic moment of the (Formula 8) and the magnetic material from (Equation 9). The present invention utilizes the above relationship. That is, the control means controls the 測定 H x / ∂x, ∂H y / ∂x, ∂H z / ∂x, ∂H y by the second measuring means.
/ ∂y, .differential.H each value of z / ∂y seek each element of the matrix B are substituted into (Equation 7) (Note (Equation 10) is also used), the inverse matrix B of the matrix B by a known method Find each element of -1 . Then, each element value of B -1 and H x ,
The positions (x, y, z) of the magnetic material are obtained by substituting the values of H y and H z into (Equation 9). Next, the control means determines r from the value of (x, y, z) just obtained, and obtains each element of the matrix A using (Equation 3). Then, each element of the inverse matrix A -1 of the matrix A is obtained by a well-known method, and the value of A -1 and the values of H x , H y , and H z by the first measuring means are substituted into (Equation 8). magnetic moment (M x, M y, M z) calculated.
【００２６】[0026]
【実施例】図２はこの発明の一実施例を示すブロック図
である。この装置は、近接する３点に配置され、各点に
おける磁界強度を互いに直交する３軸方向の成分として
出力する８個のベクトル形磁気センサ部１と、このセン
サ部１を駆動し磁界強度を入力してＡ／Ｄコンバータに
出力するセンサ制御部２と、センサ制御部２からのアナ
ログ信号をデジタル信号に変換するＡ／Ｄ変換部３と、
Ａ／Ｄ変換部３からのデータを基にして後述する手順で
磁性体の位置ｒ’と磁性体の磁気モーメントＭ’を求め
る演算部４とで構成されている。FIG. 2 is a block diagram showing an embodiment of the present invention. This device is arranged at three close points, and outputs eight magnetic field-type magnetic sensor units 1 at respective points as components in three-axis directions orthogonal to each other, and drives the sensor unit 1 to reduce the magnetic field intensity. A sensor control unit 2 for inputting and outputting to an A / D converter, an A / D conversion unit 3 for converting an analog signal from the sensor control unit 2 into a digital signal,
An arithmetic unit 4 for obtaining a position r 'of the magnetic body and a magnetic moment M' of the magnetic body based on data from the A / D conversion unit 3 in a procedure described later.
【００２７】すなわち、この実施例では磁気センサ部１
とセンサ制御部２とＡ／Ｄ変換部３と演算部４の全体
が、第一および第二の測定手段に対応する。また、この
実施例におけるセンサの配置例を示す概略図が図１であ
り、図１に示す３箇所のセンサ位置で、どの方向の磁界
強度を計測するかを示すのが図３である。図１、図３か
ら説明すると、センサ群は互いに近接するＡ点，Ｂ点，
Ｃ点の３箇所に設置される。尚ここでは、ＡＢ間の距離
をΔｘとし、ＢＣ間の距離をΔｙとしており、また点
Ａ、Ｂ、Ｃが作る角度が９０度となるよう各位置を決定
している。この３箇所のうち、Ａ点とＢ点には各々３個
のベクトル形磁気センサを設け、（互いに直交する３軸
をｘ，ｙ，ｚとすると）磁界強度のｘ方向とｙ方向とｚ
方向の成分を検出する。また、Ｃ点には２個のベクトル
形磁気センサを設け、ｙ方向とｚ方向の成分を検出す
る。すなわち、微小距離離れた３点に設けられた８個の
ベクトル形磁気センサで、ＨXA，ＨYA，ＨZA（Ａ点での
３成分）ＨXB，ＨYB，ＨZB（Ｂ点での３成分）ＨYC，Ｈ
ZC（Ｃ点での２成分）を各々測定する。ところで、この
３点は近接しているので、That is, in this embodiment, the magnetic sensor unit 1
The whole of the sensor controller 2, the A / D converter 3, and the calculator 4 correspond to the first and second measuring means. FIG. 1 is a schematic diagram showing an example of sensor arrangement in this embodiment. FIG. 3 shows which direction of the magnetic field intensity is measured at the three sensor positions shown in FIG. Referring to FIGS. 1 and 3, the sensor group includes points A, B,
It is installed at three places at point C. Note that, here, the distance between AB is Δx, the distance between BC is Δy, and each position is determined so that the angle formed by points A, B, and C is 90 degrees. Of these three points, three vector-type magnetic sensors are provided at points A and B, respectively (assuming three axes orthogonal to each other as x, y, and z), the x-direction, the y-direction, and the z-direction of the magnetic field strength.
The direction component is detected. Further, two vector-type magnetic sensors are provided at point C to detect components in the y direction and the z direction. That is, H XA , H YA , and H ZA (three components at point A) H XB , H YB , and H ZB (at point B) are provided by eight vector-type magnetic sensors provided at three points separated by a minute distance. 3 components) H YC , H
Each ZC (two components at point C) is measured. By the way, because these three points are close,
【００２８】[0028]
【数１１】 [Equation 11]
【００２９】（式１２）の関係が成立し、この結果から
行列Ｂの各要素の値が決定できる。また、磁界強度とし
ては任意の点の値、例えばＢ点の磁界ＨXB，ＨYB，ＨZB
を使用できる。さて、図２に示す装置の動作であるが、
ベクトル形磁気センサ部１は、上述のように配置された
８個の磁気センサによって各点での磁界強度ＨXA，
ＨYA，ＨZA，ＨXB，ＨYB，ＨZB，ＨYC，ＨZCを測定す
る。そして、センサ制御部２は、８個の磁気センサの駆
動をし、上記のデータを取り込みＡ／Ｄ変換部３に加え
る。Ａ／Ｄ変換部３は各データを各々デジタル信号に変
換して演算部４に出力する。演算部４は、（式１２）の
計算をしThe relationship of (Equation 12) holds, and from this result, the value of each element of the matrix B can be determined. The magnetic field strength is a value at an arbitrary point, for example, the magnetic field H XB , H YB , H ZB at the point B.
Can be used. Now, the operation of the device shown in FIG.
The vector-type magnetic sensor unit 1 uses eight magnetic sensors arranged as described above to control the magnetic field strength H XA ,
H YA, H ZA, H XB , H YB, H ZB, H YC, to measure the H ZC. Then, the sensor control unit 2 drives the eight magnetic sensors, takes in the above data, and adds it to the A / D conversion unit 3. The A / D converter 3 converts each data into a digital signal and outputs the digital signal to the calculator 4. The operation unit 4 calculates (Equation 12)
【００３０】[0030]
【数１２】 (Equation 12)
【００３１】の各値を求め、その結果を（式７）に代入
することで行列Ｂの値を求める。そして、その行列Ｂの
逆行列Ｂ-1の各要素を計算し、その値とＢ点の磁界強度
ＨXB，ＨYB，ＨZBを（式９）に代入してｘ，ｙ，ｚを求
め、磁性体の位置を特定する。また、演算部は、ｘ，
ｙ，ｚを用い（式３）から行列Ａの値を求め、行列Ａの
逆行列Ａ-1の各要素を計算する。そして、求めた行列Ａ
の逆行列Ａ-1とＢ点の磁界強度ＨXB，ＨYB，ＨZBを（式
８）に代入して磁性体の磁気モーメントＭ’を求める。The values of the matrix B are obtained by obtaining the respective values of the above and substituting the results into (Equation 7). Then, each element of the inverse matrix B -1 of the matrix B is calculated, and the values and the magnetic field strengths H XB , H YB , and H ZB at the point B are substituted into (Equation 9) to obtain x, y, and z. The position of the magnetic body is specified. In addition, the calculation unit includes x,
Using y and z, the value of the matrix A is calculated from (Equation 3), and each element of the inverse matrix A -1 of the matrix A is calculated. Then, the obtained matrix A
Magnetic field strength H XB of the inverse matrix A -1 and B point, H YB, by substituting H ZB in equation (8) determining the magnetic moment M 'of the magnetic body.
【００３２】[0032]
【発明の効果】以上説明したように、本発明に係る磁気
測定装置では、演算内容が比較的簡単であるから、高速
処理で磁性体の位置と磁気モーメントを求めることがで
きる。また、演算結果に不要な偽の解が含まれておらず
煩雑な真偽判定の処理が不要になる。As described above, in the magnetometer according to the present invention, since the content of the calculation is relatively simple, the position and magnetic moment of the magnetic body can be obtained by high-speed processing. In addition, unnecessary false solutions are not included in the operation result, and complicated truth determination processing is not required.
【図１】ベクトル形磁気センサの配置箇所を示す概略図
である。FIG. 1 is a schematic diagram showing an arrangement location of a vector-type magnetic sensor.
【図２】本発明の一実施例を示すブロック図である。FIG. 2 is a block diagram showing one embodiment of the present invention.
【図３】各センサで磁界強度のどの方向成分を測定する
かを示す図面である。FIG. 3 is a diagram showing which direction component of the magnetic field intensity is measured by each sensor.
【図４】磁性体の位置Ｏと観測点の位置Ｐを示す図面で
ある。FIG. 4 is a drawing showing a position O of a magnetic body and a position P of an observation point.
１ ベクトル形磁気センサ部 ２ センサ制御部 ３ Ａ／Ｄ変換部 ４ 演算部 ５ 制御部 DESCRIPTION OF SYMBOLS 1 Vector type magnetic sensor part 2 Sensor control part 3 A / D conversion part 4 Operation part 5 Control part
フロントページの続き (56)参考文献 特開 平３−276002（ＪＰ，Ａ) 特開 平３−176293（ＪＰ，Ａ) 特開 昭60−250267（ＪＰ，Ａ) 特開 昭54−25761（ＪＰ，Ａ) 特開 昭54−127371（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) G01R 33/00 - 33/18 Continuation of the front page (56) References JP-A-3-276002 (JP, A) JP-A-3-176293 (JP, A) JP-A-60-250267 (JP, A) JP-A-54-25761 (JP) , A) JP-A-54-127371 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) G01R 33/00-33/18
Claims (1)
する第一の測定手段と、この磁界成分についての各軸方
向の磁界傾度のうち、互いに独立な５成分を検出する第
二の測定手段と、上記第一と第二の測定手段の結果を基
にして数値計算をし磁性体の位置と磁性体の磁気モーメ
ントを求める制御手段とを備えることを特徴とする磁気
測定器。1. A first measuring means for detecting magnetic field components in three axial directions orthogonal to each other, and a second measuring means for detecting five independent magnetic field gradients among the magnetic field gradients of the magnetic field components in each axial direction. And a control means for performing numerical calculations based on the results of the first and second measuring means to obtain the position of the magnetic material and the magnetic moment of the magnetic material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3117581A JP2961945B2 (en) | 1991-05-22 | 1991-05-22 | Magnetometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3117581A JP2961945B2 (en) | 1991-05-22 | 1991-05-22 | Magnetometer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04344482A JPH04344482A (en) | 1992-12-01 |
| JP2961945B2 true JP2961945B2 (en) | 1999-10-12 |
Family
ID=14715368
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3117581A Expired - Fee Related JP2961945B2 (en) | 1991-05-22 | 1991-05-22 | Magnetometer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2961945B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6484118B1 (en) * | 2000-07-20 | 2002-11-19 | Biosense, Inc. | Electromagnetic position single axis system |
| JP5597917B2 (en) * | 2008-02-29 | 2014-10-01 | 株式会社島津製作所 | Target exploration system |
-
1991
- 1991-05-22 JP JP3117581A patent/JP2961945B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04344482A (en) | 1992-12-01 |
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