JPH08304556A - Magnetometric sensing signal processor - Google Patents
Magnetometric sensing signal processorInfo
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- JPH08304556A JPH08304556A JP11065995A JP11065995A JPH08304556A JP H08304556 A JPH08304556 A JP H08304556A JP 11065995 A JP11065995 A JP 11065995A JP 11065995 A JP11065995 A JP 11065995A JP H08304556 A JPH08304556 A JP H08304556A
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- value
- magnetic
- circuit
- likelihood ratio
- calculation circuit
- Prior art date
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- Geophysics And Detection Of Objects (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は例えば航空機に搭載さ
れ、水面下の潜水艦や沈没船などの磁性体の捜索・探知
に利用する磁気センサシステムの磁探信号処理器に関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic sensor signal processor of a magnetic sensor system which is mounted on an aircraft and used for searching and detecting a magnetic substance such as a submarine or a sunken ship under water.
【０００２】[0002]
【従来の技術】従来の磁探信号処理器は図３のような構
成であり、図において１は磁気センサ、１２は磁気セン
サにより計測される磁探信号の自己相関関数を求める自
己相関関数計算回路、１３は対数を求める対数変換回
路、１４は近似直線を求め、その傾きを磁探信号が地磁
気変動などによる雑音信号のみの場合の尤度と、雑音信
号と目標磁性体からの磁探信号とが混在する場合の尤度
との比である尤度比の計算の際に必要な係数として出力
する近似直線計算回路、５は予め求めてある目標磁性体
の磁気信号波形を参照信号波形として記憶する参照信号
波形記憶回路、６は上記係数と参照信号波形から尤度比
を求める尤度比計算回路、７は固定スレッショルドを記
憶する固定スレッショルド記憶回路、８は尤度比と固定
スレッショルドの値を比較する比較回路である。2. Description of the Related Art A conventional magnetic probe signal processor has a configuration as shown in FIG. 3, in which 1 is a magnetic sensor and 12 is an autocorrelation function calculation for obtaining an autocorrelation function of a magnetic probe signal measured by the magnetic sensor. A circuit, 13 is a logarithmic conversion circuit for obtaining a logarithm, 14 is an approximate straight line, and its inclination is the likelihood when the magnetic search signal is only a noise signal due to geomagnetic fluctuations, and the magnetic search signal from the noise signal and the target magnetic body. The approximate linear calculation circuit 5 which outputs as a coefficient necessary for the calculation of the likelihood ratio, which is the ratio of the likelihood when there is a mixture of Reference signal waveform storage circuit to be stored, 6 is a likelihood ratio calculation circuit for obtaining a likelihood ratio from the coefficient and the reference signal waveform, 7 is a fixed threshold storage circuit to store a fixed threshold, and 8 is a likelihood ratio and a fixed threshold value. A comparison circuit to compare.
【０００３】従来の磁探信号処理器は上記のように構成
され、図４のような磁探信号をΔｔ秒毎にＮ点サンプル
し、これを自己相関関数計算回路１２に入力して磁探信
号の自己相関関数を求める。ここで地磁気変動などによ
る雑音信号の自己相関関数は次式のようである。The conventional magnetic probe signal processor is constructed as described above, and samples the magnetic probe signal as shown in FIG. 4 at N points every Δt seconds and inputs this to the autocorrelation function calculation circuit 12 to detect the magnetic field. Find the autocorrelation function of the signal. Here, the autocorrelation function of the noise signal due to geomagnetic fluctuation is as follows.
【０００４】[0004]
【数１】 [Equation 1]
【０００５】よって磁探信号が雑音信号のみならば、そ
の自己相関関数は数１に従う。それを示すのが図５ａ
で、横軸はタイムラグ、縦軸は自己相関値である。図中
の点線が数１を示す曲線で、△印が磁探信号から求めた
計算値のプロット例である。ここで後で行う尤度比計算
のときに用いる尤度比Λを求める式を示す。Therefore, if the magnetic probe signal is only a noise signal, its autocorrelation function follows Equation 1. This is shown in Figure 5a.
Here, the horizontal axis is the time lag and the vertical axis is the autocorrelation value. The dotted line in the figure is a curve showing the equation 1, and the mark Δ is a plot example of the calculated value obtained from the magnetic probe signal. Here, an equation for obtaining the likelihood ratio Λ used in the likelihood ratio calculation performed later will be shown.
【０００６】[0006]
【数２】 [Equation 2]
【０００７】数２からも明らかなように、尤度比を求め
るためには数１中の係数βが必要である。このことか
ら、自己相関関数回路１２で求めた磁探信号の自己相関
関数を対数変換回路１３に入力して対数を求め、これを
近似直線計算回路１４に入力し図５ｂ（横軸はタイムラ
グ、縦軸は自己相関値の対数）のように近似直線を求
め、その傾き（つまり数１中のβ）即ち上記係数を出力
する。この値とΔｔ秒毎にサンプルしたＮ点の磁探信号
と参照信号波形記憶回路５からの図６のようなΔｔ秒で
サンプリングしたＮ点からなる参照信号波形とを尤度比
計算回路６に入力し数２に従って尤度比Λを求める。As is clear from the equation (2), the coefficient β in the equation (1) is necessary to obtain the likelihood ratio. From this, the autocorrelation function of the magnetic probe signal obtained by the autocorrelation function circuit 12 is input to the logarithmic conversion circuit 13 to obtain the logarithm, and this is input to the approximate straight line calculation circuit 14 and the graph of FIG. The vertical axis obtains an approximate straight line like the logarithm of the autocorrelation value, and outputs its slope (that is, β in equation 1), that is, the above coefficient. This value, an N-point magnetic probe signal sampled every Δt seconds, and a reference signal waveform consisting of N points sampled at Δt seconds as shown in FIG. Input and calculate the likelihood ratio Λ according to Equation 2.
【０００８】次にこの値と固定スレッショルド記憶回路
から出力される固定スレッショルドとを比較回路８に入
力し、尤度比が固定スレッショルドより大きい場合を目
標検出あり、そうでない場合を目標検出なしとして、目
標信号の自動検出を行う。Next, this value and the fixed threshold output from the fixed threshold storage circuit are input to the comparison circuit 8, and if the likelihood ratio is larger than the fixed threshold, target detection is performed, and if not, target detection is not performed. Automatically detect the target signal.
【０００９】[0009]
【発明が解決しようとする課題】従来の磁探信号処理器
は、以上説明したように係数を求めるために、まず磁探
信号の自己相関関数を求め、これを対数に変換し、さら
にこの対数データの近似直線を求めてその傾きを係数と
するというようにアルゴリズムが複雑である故、演算処
理に時間がかかるという課題があった。In order to obtain the coefficient as described above, the conventional magnetic probe signal processor first obtains the autocorrelation function of the magnetic probe signal, converts this into a logarithm, and then this logarithm. Since the algorithm is complicated, such as obtaining an approximate straight line of data and using the slope as a coefficient, there is a problem that the calculation process takes time.
【００１０】また目標検出ありの判別は固定スレッショ
ルドによる検出であるので、雑音による尤度比の分散が
大きい場合には誤検出する可能性が高いという課題があ
った。Further, since the determination as to whether or not there is a target detection is a detection by a fixed threshold, there is a problem in that there is a high possibility of erroneous detection when the likelihood ratio variance due to noise is large.
【００１１】この発明は、上記の課題を解決するために
なされたものであり、係数の計算を簡単なアルゴリズム
で行うことで演算処理時間の短縮化という機能を得よう
とするものである。The present invention has been made in order to solve the above problems, and is intended to obtain the function of shortening the calculation processing time by performing the calculation of the coefficient by a simple algorithm.
【００１２】また目標磁性体がない場合に観測した一定
時間の尤度比の標準偏差から設定するスレッショルドに
より、目標捜索中に観測する尤度比の標準偏差に対応し
たスレッショルドによる目標磁性体信号の自動検出を行
い、誤検出する可能性を押さえるという機能を得ようと
するものである。Further, a target magnetic signal with a threshold corresponding to the standard deviation of the likelihood ratio observed during the target search is obtained by the threshold set from the standard deviation of the likelihood ratio observed for a fixed time when there is no target magnetic material. It is intended to obtain a function of performing automatic detection and suppressing the possibility of false detection.
【００１３】[0013]
【課題を解決するための手段】この発明の実施例１によ
る磁探信号処理装置は、磁気センサと、磁気センサによ
り計測される磁探信号の平均値を求める平均値計算回路
と、平均値と磁探信号とから磁探信号の分散を求める分
散計算回路と、分散を２倍した値の逆数である係数を求
める係数計算回路と、予め求めてある目標磁性体の磁気
信号波形を参照信号波形として記憶する参照信号波形記
憶回路と、分散を２倍した値の逆数と参照信号波形とか
ら、磁探信号が地磁気変動などによる雑音信号のみの場
合の尤度と、雑音信号と目標磁性体からの磁気信号とが
混在する場合の尤度との尤度比を求める尤度比計算回路
と、固定スレッショルドを記憶する固定スレッショルド
記憶回路と、尤度比と固定スレッショルドとの値を比較
する比較回路とから構成され、磁探信号を一定時間サン
プルし、これを上記平均値計算回路に入力して平均値を
求め、次にこの値とサンプルした磁探信号とを上記分散
計算回路に入力し分散を求め、さらにこの値を上記係数
計算回路に入力して分散を２倍した値の逆数を求め、こ
の値とサンプルした磁探信号と上記参照信号波形記憶回
路からの参照信号波形とを上記尤度比計算回路に入力し
尤度比を求め、この値と固定スレッショルドとを上記比
較回路に入力し、尤度比が固定スレッショルドより大き
い場合を目標検出あり、そうでない場合を目標検出なし
として、目標信号の自動検出ができるようにしたもので
ある。A magnetic probe signal processing apparatus according to a first embodiment of the present invention includes a magnetic sensor, an average value calculation circuit for obtaining an average value of magnetic probe signals measured by the magnetic sensor, and an average value. A dispersion calculation circuit for obtaining the dispersion of the magnetic search signal from the magnetic search signal, a coefficient calculation circuit for obtaining a coefficient that is the reciprocal of the value obtained by doubling the dispersion, and a magnetic signal waveform of the target magnetic body which is obtained in advance as a reference signal waveform. From the reference signal waveform storage circuit that stores as, the reciprocal of the value obtained by doubling the variance, and the reference signal waveform, the likelihood in the case where the magnetic search signal is only a noise signal due to geomagnetic fluctuations, and the noise signal and the target magnetic material. Likelihood ratio calculation circuit that obtains the likelihood ratio with the likelihood when a mixed magnetic signal is present, a fixed threshold storage circuit that stores a fixed threshold, and a comparison circuit that compares the value of the likelihood ratio and the fixed threshold. And It is configured to sample the magnetic probe signal for a certain period of time, input this to the average value calculation circuit to obtain an average value, and then input this value and the sampled magnetic probe signal to the dispersion calculation circuit to obtain the dispersion. Further, this value is input to the coefficient calculation circuit to obtain the reciprocal of the value obtained by doubling the variance, and this value, the sampled magnetic probe signal, and the reference signal waveform from the reference signal waveform storage circuit are used for the likelihood ratio. The likelihood ratio is input to the calculation circuit, and this value and the fixed threshold are input to the above comparison circuit. When the likelihood ratio is larger than the fixed threshold, target detection is performed. The automatic detection of is made possible.
【００１４】また、この発明による実施例２による磁探
信号処理装置は、磁気センサと、磁気センサにより計測
される磁探信号の平均値を求める平均値計算回路と、平
均値と磁探信号とから磁探信号の分散を求める分散計算
回路と、分散を２倍した値の逆数である係数を求める係
数計算回路と、予め求めてある目標磁性体の磁気信号波
形を参照信号波形として記憶する参照信号波形記憶回路
と、分散を２倍した値の逆数と参照信号波形とから、磁
探信号が地磁気変動などによる雑音信号のみの場合の尤
度と、雑音信号と目標磁性体からの磁気信号とが混在す
る場合の尤度との尤度比を求める尤度比計算回路と、磁
探信号収拾時の運用状況に関してスレッショルド設定モ
ードと目標磁性体捜索モードとについて選択を行う選択
回路と、尤度比の平均値を求める平均値計算回路と、尤
度比と平均値とから尤度比の標準偏差を求める標準偏差
計算回路と、標準偏差と平均値とからスレッショルドを
求めるスレッショルド設定回路と、スレッショルドと尤
度比との値を比較する比較回路とから構成され、磁探信
号を一定時間サンプルし、これを上記平均値計算回路に
入力して平均値を求め、次にこの値とサンプルした磁探
信号を上記分散計算回路に入力し分散を求め、さらにこ
の値を上記係数計算回路に入力して分散を２倍した値の
逆数を求め、この値とサンプルした磁探信号と上記参照
信号波形記憶回路からの参照信号波形とを上記尤度比計
算回路に入力し尤度比を求め、上記選択回路のスレッシ
ョルド設定モードを選択し、上記尤度比計算回路から出
力される尤度比を一定時間サンプルし、これを上記平均
値計算回路に入力して平均値を求め、この値とサンプル
した尤度比とを上記標準偏差計算回路に入力して標準偏
差を求め、さらにこの値と平均値とを上記スレッショル
ド設定回路に入力しスレッショルドを求める。次に上記
選択回路で目標磁性体捜索モードを選択した場合の上記
尤度比計算回路からの出力である尤度比と、上記スレッ
ショルドの値とを上記比較回路に入力し、尤度比がスレ
ッショルドより大きい場合を目標検出あり、そうでない
場合を目標検出なしとして、目標信号の自動検出ができ
るようにしたものである。The magnetic probe signal processing apparatus according to the second embodiment of the present invention includes a magnetic sensor, an average value calculation circuit for obtaining an average value of magnetic probe signals measured by the magnetic sensor, an average value and a magnetic probe signal. A dispersion calculation circuit for obtaining the dispersion of the magnetic probe signal from the above, a coefficient calculation circuit for obtaining a coefficient that is the reciprocal of the value obtained by doubling the dispersion, and a magnetic signal waveform of the target magnetic material that has been obtained in advance is stored as a reference signal waveform. From the signal waveform storage circuit, the reciprocal of the value obtained by doubling the variance, and the reference signal waveform, the likelihood in the case where the magnetic search signal is only a noise signal due to geomagnetic fluctuation, the noise signal, and the magnetic signal from the target magnetic body, , A likelihood ratio calculation circuit that obtains a likelihood ratio with the likelihood when there is a mixture, a selection circuit that selects the threshold setting mode and the target magnetic material search mode with respect to the operation status at the time of collecting the magnetic search signal, and the likelihood. Ratio of An average value calculation circuit that calculates the average value, a standard deviation calculation circuit that calculates the standard deviation of the likelihood ratio from the likelihood ratio and the average value, a threshold setting circuit that calculates the threshold value from the standard deviation and the average value, and a threshold and likelihood It is composed of a comparison circuit that compares the value with the power ratio, samples the magnetic probe signal for a certain period of time, inputs it to the above average value calculation circuit to obtain an average value, and then samples this value with the sampled magnetic probe signal. Is input to the dispersion calculation circuit to calculate the dispersion, and this value is input to the coefficient calculation circuit to calculate the reciprocal of the value obtained by doubling the dispersion. This value, the sampled magnetic probe signal and the reference signal waveform storage circuit are calculated. And a reference signal waveform from the input to the likelihood ratio calculation circuit to obtain the likelihood ratio, select the threshold setting mode of the selection circuit, sample the likelihood ratio output from the likelihood ratio calculation circuit for a certain period of time. , This is input to the average value calculation circuit to obtain an average value, this value and the sampled likelihood ratio are input to the standard deviation calculation circuit to obtain the standard deviation, and this value and the average value are described above. Input to the threshold setting circuit to obtain the threshold. Next, the likelihood ratio, which is the output from the likelihood ratio calculation circuit when the target magnetic material search mode is selected by the selection circuit, and the threshold value are input to the comparison circuit, and the likelihood ratio is set to the threshold value. The target signal is automatically detected if the value is larger than the target value and if the target value is not detected, the target signal is not detected.
【００１５】[0015]
【作用】この発明の実施例１によれば、磁気センサによ
り計測される磁探信号が地磁気変動などに雑音信号のみ
の場合の尤度と、雑音信号と目標磁性体からの磁気信号
とが混在する場合との尤度との比である尤度比の計算の
ために必要な係数が、磁探信号の分散を２倍した値の逆
数から求まり、従来のアルゴリズムに比較して簡単な演
算処理で求まり、尤度比計算までの処理時間が短縮する
という機能を得ることができる。According to the first embodiment of the present invention, the likelihood in the case where the magnetic probe signal measured by the magnetic sensor is only a noise signal due to geomagnetic fluctuations and the noise signal and the magnetic signal from the target magnetic material are mixed. The coefficient required to calculate the likelihood ratio, which is the ratio of the likelihood to the case of performing, is obtained from the reciprocal of the value obtained by doubling the variance of the magnetic search signal, and is a simple arithmetic process compared to the conventional algorithm. It is possible to obtain the function of shortening the processing time until the calculation of the likelihood ratio.
【００１６】また、この発明の実施例２によれば、尤度
比の標準偏差から決まるスレッショルドによる目標信号
の自動検出であるので、従来の固定スレッショルドによ
る自動検出よりも誤検出する可能性が押さえられるとい
う機能を得ることができる。Further, according to the second embodiment of the present invention, since the target signal is automatically detected by the threshold determined by the standard deviation of the likelihood ratio, the possibility of erroneous detection is suppressed as compared with the conventional automatic detection by the fixed threshold. It is possible to obtain the function to be performed.
【００１７】[0017]
実施例１．図１はこの発明の実施例１を示す構成図であ
り、図において１は磁気センサ、２は磁気センサにより
計測される磁探信号の平均値を求める平均値計算回路、
３は平均値と磁探信号とから磁探信号の分散を求める分
散計算回路、４は分散を２倍した値の逆数である係数を
求める係数計算回路、５は予め求めてある目標磁性体の
磁気信号波形を参照信号波形として記憶する参照信号波
形記憶回路、６は分散を２倍した値の逆数と参照信号波
形とから、磁探信号が地磁気変動などによる雑音信号の
みの場合の尤度と、雑音信号と目標磁性体からの磁気信
号とが混在する場合の尤度との尤度比を求める尤度比計
算回路、７は固定スレッショルドを記憶する固定スレッ
ショルド記憶回路、８は尤度比と固定スレッショルドと
の値を比較する比較回路である。Example 1. 1 is a block diagram showing a first embodiment of the present invention, in which 1 is a magnetic sensor, 2 is an average value calculation circuit for obtaining an average value of a magnetic probe signal measured by the magnetic sensor,
3 is a dispersion calculation circuit for obtaining the dispersion of the magnetic search signal from the average value and the magnetic search signal, 4 is a coefficient calculation circuit for obtaining a coefficient that is the reciprocal of the value obtained by doubling the dispersion, and 5 is a target magnetic material that has been previously obtained. A reference signal waveform storage circuit that stores a magnetic signal waveform as a reference signal waveform. Reference numeral 6 is a reciprocal of a value obtained by doubling the variance and a reference signal waveform. , A likelihood ratio calculation circuit for obtaining the likelihood ratio between the noise signal and the likelihood when the magnetic signal from the target magnetic material is mixed, 7 is a fixed threshold storage circuit for storing a fixed threshold, and 8 is a likelihood ratio. It is a comparison circuit that compares the value with a fixed threshold.
【００１８】磁気センサ１からの図４のような磁気信号
をΔｔ秒毎にＮ点観測して、これを平均値計算回路２に
入力して平均値を求める。このとき入力する磁探信号を
ｕ0、ｕ1 、・・・・、ＵN-1 とし平均値をｕとすれ
ば、ｕは次式で求まる。A magnetic signal as shown in FIG. 4 from the magnetic sensor 1 is observed at N points every Δt seconds, and this is input to the average value calculation circuit 2 to obtain an average value. If the magnetic probe signals input at this time are u 0 , u 1 , ..., U N-1, and the average value is u, u can be obtained by the following equation.
【００１９】[0019]
【数３】 (Equation 3)
【００２０】次にこの値と観測した磁探信号とを分散計
算回路３に入力し分散を求める。このとき求める分散を
Ｖａｒとすれば、Ｖａｒは次式で求まる。Next, this value and the observed magnetic probe signal are input to the dispersion calculation circuit 3 to obtain the dispersion. If the variance calculated at this time is Var, Var can be calculated by the following equation.
【００２１】[0021]
【数４】 [Equation 4]
【００２２】さらにこの値を計数計算回路４に入力して
分散を２倍した値の逆数を求める。ここで、数１で示し
た自己相関関数Ｒ（τ）で、τ＝０のときの値は分散で
あるので次式のように示される。Further, this value is input to the counting calculation circuit 4 to obtain the reciprocal of the value obtained by doubling the variance. Here, in the autocorrelation function R (τ) shown in the equation 1, the value when τ = 0 is the variance, and therefore it is expressed as the following equation.
【００２３】[0023]
【数５】 (Equation 5)
【００２４】数５から、分散の２倍の逆数は数１中のβ
と等しく、従来の磁探信号処理器の中で求めていた係数
と等しい。この値とΔｔ秒毎にサンプルしたＮ点の磁探
信号と参照信号波形記憶回路５からの図６のようなΔｔ
秒でサンプリングしたＮ点からなる参照信号波形とを尤
度比計算回路６に入力し数２に従い尤度比を求め、この
値と固定スレッショルドとを比較回路８に入力し、尤度
比が固定スレッショルドより大きい場合を目標検出あ
り、そうでない場合を目標検出なしとして、目標信号の
自動検出を行う。From Equation 5, the reciprocal of twice the variance is β in Equation 1.
And is equal to the coefficient found in the conventional magnetic probe signal processor. This value and Δt as shown in FIG. 6 from the N-point magnetic probe signal and the reference signal waveform storage circuit 5 sampled every Δt seconds.
The reference signal waveform consisting of N points sampled in seconds is input to the likelihood ratio calculation circuit 6, the likelihood ratio is calculated according to Equation 2, and this value and a fixed threshold are input to the comparison circuit 8 to fix the likelihood ratio. The target signal is automatically detected when the value is larger than the threshold and the target is detected, and when not, the target is not detected.
【００２５】実施例２．図２はこの発明の実施例２を示
す構成図であり、図において１は磁気センサ、２は磁気
センサにより計測される磁探信号の平均値を求める平均
値計算回路、３は平均値と磁探信号とから磁探信号の分
散を求める分散計算回路、４は分散を２倍した値の逆数
である係数を求める計数計算回路、５は予め求めてある
目標磁性体の磁気信号波形を参照信号波形として記憶す
る参照信号波形記憶回路、６は分散を２倍した値の逆数
と参照信号波形とから、磁探信号が地磁気変動などによ
る雑音信号のみの場合の尤度と、雑音信号と目標磁性体
からの磁気信号とが混在する場合の尤度との尤度比を求
める尤度比計算回路、９は磁探信号収拾時の運用状況に
関してスレッショルド設定モードと目標磁性体捜索モー
ドの場合とについて選択を行う選択回路、２は尤度比の
平均値を求める平均値計算回路、１０は尤度比と平均値
とから尤度比の標準偏差を求める標準偏差計算回路、１
１は標準偏差と平均値とからスレッショルドを求めるス
レッショルド設定回路、８はスレッショルドと尤度比と
の値を比較する比較回路である。Example 2. 2 is a block diagram showing a second embodiment of the present invention. In FIG. 2, 1 is a magnetic sensor, 2 is an average value calculation circuit for obtaining an average value of a magnetic probe signal measured by the magnetic sensor, and 3 is an average value and a magnetic field. A dispersion calculation circuit for obtaining the dispersion of the magnetic search signal from the probe signal, 4 is a counting calculation circuit for obtaining a coefficient that is the reciprocal of the value obtained by doubling the dispersion, and 5 is a reference signal that is the magnetic signal waveform of the target magnetic body that has been obtained in advance. A reference signal waveform storage circuit for storing as a waveform, 6 is the reciprocal of the value obtained by doubling the variance and the reference signal waveform, and the likelihood when the magnetic search signal is only a noise signal due to geomagnetic fluctuation, the noise signal and the target magnetism. Likelihood ratio calculation circuit for obtaining the likelihood ratio with the likelihood when magnetic signals from the body are mixed, and 9 for the threshold setting mode and the target magnetic material search mode regarding the operation status at the time of collecting the magnetic search signal A selection circuit that makes the selection, Average value calculating circuit, a standard deviation calculation circuit for calculating the standard deviation of the likelihood ratio from the average value and the likelihood ratio 10 to obtain an average value of the likelihood ratio is 1
Reference numeral 1 is a threshold setting circuit for obtaining a threshold value from a standard deviation and an average value, and 8 is a comparison circuit for comparing the threshold value and the likelihood ratio.
【００２６】磁気センサ１からの図４のような磁探信号
をΔｔ秒毎にＮ点観測して、これを平均値計算回路２に
入力して平均値を求める。このとき入力する磁探信号を
ｕ0、ｕ1 、・・・、ｕN-1 とし平均値をｕとすれば、
ｕは上記数３で求まる。A magnetic probe signal from the magnetic sensor 1 as shown in FIG. 4 is observed every Δt seconds at N points, and this is input to the average value calculation circuit 2 to obtain an average value. Let u 0 , u 1 , ..., U N−1 be the magnetic probe signals input at this time, and let the average value be u.
u can be obtained by the above equation 3.
【００２７】次にこの値と観測した磁探信号とを分散計
算回路３に入力し分散を求める。このとき求める分散を
Ｖａｒとすれば、Ｖａｒは上記数４で求まる。Next, this value and the observed magnetic probe signal are input to the dispersion calculation circuit 3 to obtain the dispersion. If the variance to be obtained at this time is Var, then Var can be obtained by the above equation 4.
【００２８】さらにこの値を係数計算回路４に入力して
分散を２倍した値の逆数を求め、この値とΔｔ秒毎にサ
ンプルしたＮ点の磁探信号と参照信号波形記憶回路５か
らの図６のようなΔｔ秒でサンプリングしたＮ点からな
る参照信号波形とを尤度比計算回路６に入力し、数２に
従って尤度比を求める。Further, this value is input to the coefficient calculation circuit 4 to obtain the reciprocal of the value obtained by doubling the dispersion, and this value and the N-point magnetic probe signal sampled every Δt seconds and the reference signal waveform storage circuit 5 A reference signal waveform consisting of N points sampled at Δt seconds as shown in FIG. 6 is input to the likelihood ratio calculation circuit 6, and the likelihood ratio is calculated according to the equation 2.
【００２９】スレッショルドを設定するために選択回路
９のスレッショルド設定モードを選択し、尤度比計算回
路６から出力される尤度比を一定時間Ｍ点サンプルし、
これを平均値計算回路２に入力して平均値を求める。こ
のとき尤度比をΛ0 、Λ1 、・・・、ΛM-1 、平均値を
ｍとすれば、次式で求まる。In order to set the threshold, the threshold setting mode of the selection circuit 9 is selected, the likelihood ratio output from the likelihood ratio calculation circuit 6 is sampled for M points for a fixed time,
This is input to the average value calculation circuit 2 to calculate the average value. At this time, if the likelihood ratio is Λ 0 , Λ 1 , ..., Λ M-1 , and the average value is m, the following equation is obtained.
【００３０】[0030]
【数６】 (Equation 6)
【００３１】次にこの値とサンプルしたＭ点の尤度比と
を標準偏差計算回路１０に入力して標準偏差を求める。
このとき標準偏差をσとすれば、次式で求まる。Next, this value and the likelihood ratio of the sampled M points are input to the standard deviation calculation circuit 10 to obtain the standard deviation.
At this time, if the standard deviation is σ, it can be obtained by the following equation.
【００３２】[0032]
【数７】 (Equation 7)
【００３３】この値と上記平均値とをスレッショルド設
定回路１１に入力し、ｍ＋σ、ｍ＋２σ、ｍ＋３σとい
うようなスレッショルドを求める。This value and the above average value are input to the threshold setting circuit 11 to obtain thresholds such as m + σ, m + 2σ and m + 3σ.
【００３４】目標磁性体の捜索をするために選択回路９
で目標磁性体捜索モードを選択し、尤度比計算回路６か
らの出力である尤度比と、スレッショルドの値とを比較
回路８に入力し、尤度比がスレッショルドより大きい場
合を目標検出あり、そうでない場合を目標検出なしとし
て、目標信号の自動検出を行う。A selection circuit 9 for searching for a target magnetic substance.
The target magnetic material search mode is selected with, the likelihood ratio output from the likelihood ratio calculation circuit 6 and the threshold value are input to the comparison circuit 8, and target detection is performed when the likelihood ratio is greater than the threshold value. If not, the target signal is automatically detected with no target detection.
【００３５】[0035]
【発明の効果】この発明の実施例１によれば、磁気セン
サにより計測される磁探信号の平均値を求める平均値計
算回路と、平均値と磁探信号とから磁探信号の分散を求
める分散計算回路と、分散を２倍した値の逆数である係
数を求める係数計算回路と、予め求めてある目標磁性体
の磁気信号波形を参照信号波形として記憶する参照信号
波形記憶回路と、分散を２倍した値の逆数と参照信号波
形とから、磁探信号が地磁気変動などによる雑音信号の
みの場合の尤度と、雑音信号と目標磁性体からの磁気信
号とが混在する場合の尤度との尤度比を求める尤度比計
算回路と、固定スレッショルドを記憶する固定スレッシ
ョルド記憶回路と、尤度比と固定スレッショルドとの値
を比較する比較回路とから構成され、磁探信号を一定時
間サンプルし、これを上記平均値計算回路に入力して平
均値を求め、次にこの値とサンプルした磁探信号とを上
記分散計算回路に入力し分散を求め、さらにこの値を上
記係数計算回路に入力して分散を２倍した値の逆数を求
め、この値とサンプルした磁探信号と上記参照信号波形
記憶回路からの参照信号波形とを上記尤度比計算回路に
入力し尤度比を求め、この値と固定スレッショルドとを
上記比較回路に入力し、尤度比が固定スレッショルドよ
り大きい場合を目標検出あり、そうでない場合を目標検
出なしとして、目標信号の自動検出を行う機能を得るこ
とができるという効果がある。According to the first embodiment of the present invention, an average value calculation circuit for obtaining the average value of the magnetic probe signals measured by the magnetic sensor, and the dispersion of the magnetic probe signals from the average value and the magnetic probe signal are obtained. A dispersion calculation circuit, a coefficient calculation circuit that obtains a coefficient that is the reciprocal of the value obtained by doubling the dispersion, a reference signal waveform storage circuit that stores the previously obtained magnetic signal waveform of the target magnetic material as a reference signal waveform, and the dispersion From the reciprocal of the doubled value and the reference signal waveform, the likelihood when the magnetic search signal is only a noise signal due to geomagnetic variations and the likelihood when the noise signal and the magnetic signal from the target magnetic material are mixed. It consists of a likelihood ratio calculation circuit that calculates the likelihood ratio of the, a fixed threshold storage circuit that stores a fixed threshold, and a comparison circuit that compares the values of the likelihood ratio and the fixed threshold. And this Is input to the average value calculation circuit to obtain an average value, then this value and the sampled magnetic probe signal are input to the dispersion calculation circuit to obtain the dispersion, and this value is input to the coefficient calculation circuit. The reciprocal of the value obtained by doubling the variance is obtained, this value, the sampled magnetic probe signal and the reference signal waveform from the reference signal waveform storage circuit are input to the likelihood ratio calculation circuit to obtain the likelihood ratio, and this value is calculated. And the fixed threshold are input to the above-mentioned comparison circuit, the target detection is performed when the likelihood ratio is larger than the fixed threshold, and the target detection is not performed when the likelihood ratio is not, and the function of automatically detecting the target signal can be obtained. There is.
【００３６】この実施例２によれば、磁気センサにより
計測される磁探信号の平均値を求める平均値計算回路
と、平均値と磁探信号とから磁探信号の分散を求める分
散計算回路と、分散を２倍した値の逆数である係数を求
める係数計算回路と、予め求めてある目標磁性体の磁気
信号波形を参照信号波形として記憶する参照信号波形記
憶回路と、分散を２倍した値の逆数と参照信号波形とか
ら、磁探信号が地磁気変動などによる雑音信号のみの場
合の尤度と、雑音信号と目標磁性体からの磁気信号とが
混在する場合の尤度との尤度比を求める尤度比計算回路
と、磁探信号収拾時の運用状況に関してスレッショルド
設定モードと目標磁性体捜索モードの場合とについて選
択を行う選択回路と、尤度比の平均値を求める平均値計
算回路と、尤度比と平均値とから尤度比の標準偏差を求
める標準偏差計算回路と、標準偏差と平均値とからスレ
ッショルドを求めるスレッショルド設定回路と、スレッ
ショルドと尤度比との値を比較する比較回路とから構成
され、磁探信号を一定時間サンプルし、これを上記平均
値計算回路に入力して平均値を求め、次にこの値とサン
プルした磁探信号を上記分散計算回路に入力し分散を求
め、さらにこの値を上記係数計算回路に入力して分散を
２倍した値の逆数を求め、この値とサンプルした磁探信
号と上記参照信号波形記憶回路からの参照信号波形とを
上記尤度比計算回路に入力し尤度比を求め、上記選択回
路のスレッショルド設定モードを選択し、上記尤度比計
算回路から出力される尤度比を一定時間サンプルし、こ
れを上記平均値計算回路に入力して平均値を求め、この
値とサンプルした尤度比とを上記標準偏差計算回路に入
力して標準偏差を求め、さらにこの値を上記スレッショ
ルド係数乗算回路に入力しスレッショルドを求める。次
に上記選択回路で目標磁性体捜索モードを選択した場合
の上記尤度比計算回路からの出力である尤度比と、スレ
ッショルドの値とを上記比較回路に入力し、尤度比がス
レッショルドより大きい場合を目標検出あり、そうでな
い場合を目標検出なしとして、目標信号の自動検出を行
う機能を得ることができるという効果がある。According to the second embodiment, an average value calculating circuit for obtaining the average value of the magnetic probe signals measured by the magnetic sensor, and a dispersion calculating circuit for obtaining the dispersion of the magnetic probe signals from the average value and the magnetic probe signal. , A coefficient calculation circuit that obtains a coefficient that is the reciprocal of the value obtained by doubling the variance, a reference signal waveform storage circuit that stores the previously obtained magnetic signal waveform of the target magnetic material as the reference signal waveform, and a value that doubles the variance The likelihood ratio between the likelihood when the magnetic probe signal is only a noise signal due to geomagnetic fluctuations and the likelihood when the noise signal and the magnetic signal from the target magnetic material are mixed from the reciprocal of , A selection circuit for selecting the threshold setting mode and the target magnetic material search mode regarding the operating condition at the time of collecting the magnetic search signal, and an average value calculation circuit for calculating the average value of the likelihood ratio. And the likelihood ratio It consists of a standard deviation calculation circuit that calculates the standard deviation of the likelihood ratio from the average value, a threshold setting circuit that calculates the threshold value from the standard deviation and the average value, and a comparison circuit that compares the values of the threshold and the likelihood ratio. , The magnetic probe signal is sampled for a certain period of time, this is input to the average value calculation circuit to obtain an average value, and then this value and the sampled magnetic probe signal are input to the dispersion calculation circuit to obtain the dispersion. The value is input to the coefficient calculation circuit to obtain the reciprocal of the value obtained by doubling the variance, and this value, the sampled magnetic probe signal and the reference signal waveform from the reference signal waveform storage circuit are input to the likelihood ratio calculation circuit. Input the likelihood ratio, select the threshold setting mode of the above selection circuit, sample the likelihood ratio output from the above likelihood ratio calculation circuit for a certain period of time, and input this to the above average value calculation circuit. Calculated values, a standard deviation and the value and the sampled likelihood ratio is input to the standard deviation calculation circuit, further the value determining the threshold input to the threshold coefficient multiplying circuit. Next, when the target magnetic material search mode is selected by the selection circuit, the likelihood ratio which is the output from the likelihood ratio calculation circuit and the threshold value are input to the comparison circuit, and the likelihood ratio is calculated from the threshold value. There is an effect that it is possible to obtain the function of automatically detecting the target signal by setting the target detection when the value is large and not detecting the target when the value is not large.
【図１】 この発明による磁探信号処理装置の実施例１
を示す図である。FIG. 1 is a first embodiment of a magnetic probe signal processing apparatus according to the present invention.
FIG.
【図２】 この発明による磁探信号処理装置の実施例２
を示す図である。FIG. 2 is a second embodiment of the magnetic probe signal processing apparatus according to the present invention.
FIG.
【図３】 従来の磁探信号処理装置を示す図である。FIG. 3 is a diagram showing a conventional magnetic probe signal processing apparatus.
【図４】 磁気センサが観測する磁探信号の波形を示す
図である。FIG. 4 is a diagram showing a waveform of a magnetic probe signal observed by a magnetic sensor.
【図５】 雑音信号の自己相関関数から係数βを求める
方法を説明するために用いる図である。FIG. 5 is a diagram used for explaining a method of obtaining a coefficient β from an autocorrelation function of a noise signal.
【図６】 目標磁性体の磁気信号として参照波形記憶回
路に記憶される波形の一例を示す図である。FIG. 6 is a diagram showing an example of a waveform stored in a reference waveform storage circuit as a magnetic signal of a target magnetic body.
１ 磁気センサ、２ 平均値計算回路、３ 分散計算回
路、４ 係数計算回路、５ 参照信号波形記憶回路、６
尤度比計算回路、７ 固定スレッショルド記憶回路、
８ 比較回路、９ 選択回路、１０ 標準偏差計算回
路、１１ スレッショルド設定回路、１２ 自己相関関
数計算回路、１３ 対数変換回路、１４近似直線計算回
路。1 magnetic sensor, 2 average value calculation circuit, 3 dispersion calculation circuit, 4 coefficient calculation circuit, 5 reference signal waveform storage circuit, 6
Likelihood ratio calculation circuit, 7 fixed threshold storage circuit,
8 comparison circuit, 9 selection circuit, 10 standard deviation calculation circuit, 11 threshold setting circuit, 12 autocorrelation function calculation circuit, 13 logarithmic conversion circuit, 14 approximate straight line calculation circuit.
Claims (2)
れる磁探信号の平均値を求める平均値計算回路と、平均
値と磁探信号とから磁探信号の分散を求める分散計算回
路と、分散を２倍した値の逆数である係数を求める係数
計算回路と、予め求めてある目標磁性体の磁気信号波形
を参照信号波形として記憶する参照信号波形記憶回路
と、分散を２倍した値の逆数と参照信号波形とから、磁
探信号が地磁気変動などによる雑音信号のみの場合の尤
度と雑音信号と目標磁性体からの磁気信号とが混在する
場合の尤度との尤度比を求める尤度比計算回路と、固定
スレッショルドを記憶する固定スレッショルド記憶回路
と、尤度比と固定スレッショルドとの値を比較する比較
回路とから構成され、磁探信号を一定時間サンプルし、
これを上記平均値計算回路に入力して平均値を求め、次
にこの値とサンプルした磁探信号とを上記分散計算回路
に入力し分散を求め、さらにこの値を上記係数計算回路
に入力して分散を２倍した値の逆数を求め、この値とサ
ンプルした磁探信号と上記参照信号波形記憶回路からの
参照信号波形とを上記尤度比計算回路に入力し尤度比を
求め、この値と固定スレッショルドとを上記比較回路に
入力し、尤度比が固定スレッショルドより大きい場合を
目標検出あり、そうでない場合を目標検出なしとして、
目標信号の自動検出ができるようにしたことを特徴とす
る磁探信号処理器。1. A magnetic sensor, an average value calculation circuit for obtaining an average value of magnetic detection signals measured by the magnetic sensor, a dispersion calculation circuit for obtaining dispersion of the magnetic detection signal from the average value and the magnetic detection signal, and a dispersion. Coefficient calculation circuit for obtaining a coefficient that is the reciprocal of the value obtained by multiplying by, a reference signal waveform storage circuit that stores the previously obtained magnetic signal waveform of the target magnetic material as a reference signal waveform, and the inverse of the value obtained by doubling the variance. And the reference signal waveform, the likelihood ratio between the likelihood when the magnetic search signal is only a noise signal due to geomagnetic fluctuations and the likelihood when the noise signal and the magnetic signal from the target magnetic material are mixed is calculated. A ratio ratio calculation circuit, a fixed threshold storage circuit that stores a fixed threshold, and a comparison circuit that compares the values of the likelihood ratio and the fixed threshold, and samples the magnetic probe signal for a certain period of time.
This is input to the average value calculation circuit to obtain an average value, then this value and the sampled magnetic probe signal are input to the dispersion calculation circuit to obtain the dispersion, and this value is further input to the coefficient calculation circuit. Then, the reciprocal of the value obtained by doubling the variance is obtained, and this value, the sampled magnetic probe signal and the reference signal waveform from the reference signal waveform storage circuit are input to the likelihood ratio calculation circuit to obtain the likelihood ratio. A value and a fixed threshold are input to the above comparison circuit, and if the likelihood ratio is greater than the fixed threshold, target detection is performed, and if not, target detection is not performed.
A magnetic probe signal processor characterized by being capable of automatically detecting a target signal.
れる磁探信号の平均値を求める平均値計算回路と、平均
値と磁探信号とから磁探信号の分散を求める分散計算回
路と、分散を２倍した値の逆数である係数を求める係数
計算回路と、予め求めてある目標磁性体の磁気信号波形
を参照信号波形として記憶する参照信号波形記憶回路
と、分散を２倍した値の逆数と参照信号波形とから、磁
探信号が地磁気変動などによる雑音信号のみの場合の尤
度と、雑音信号と目標磁性体からの磁気信号とが混在す
る場合の尤度との尤度比を求める尤度比計算回路と、磁
探信号収拾時の運用状況に関してスレッショルド設定モ
ードと目標磁性体捜索モードとについて選択を行う選択
回路と、尤度比の平均値を求める平均値計算回路と、尤
度比と平均値とから尤度比の標準偏差を求める標準偏差
計算回路と、標準偏差と平均値とからスレッショルドを
求めるスレッショルド設定回路と、スレッショルドと尤
度比との値を比較する比較回路とから構成され、磁探信
号を一定時間サンプルし、これを上記平均値計算回路に
入力して平均値を求め、次にこの値とサンプルした磁探
信号を上記分散計算回路に入力し分散を求め、さらにこ
の値を上記係数計算回路に入力して分散を２倍した値の
逆数を求め、この値とサンプルした磁探信号と上記参照
信号波形記憶回路からの参照信号波形とを上記尤度比計
算回路に入力し尤度比を求め、上記選択回路のスレッシ
ョルド設定モードを選択し、上記尤度比計算回路から出
力される尤度比を一定時間サンプルし、これを上記平均
値計算回路に入力して平均値を求め、この値とサンプル
した尤度比とを上記標準偏差計算回路に入力して標準偏
差を求め、さらにこの値と平均値とを上記スレッショル
ド設定回路に入力しスレッショルドを求める。次に上記
選択回路で目標磁性体捜索モードを選択した場合の上記
尤度比計算回路からの出力である尤度比と、スレッショ
ルドの値とを上記比較回路に入力し、尤度比がスレッシ
ョルドより大きい場合を目標検出あり、そうでない場合
を目標検出なしとして、目標信号の自動検出ができるよ
うにしたことを特徴とする磁探信号処理器。2. A magnetic sensor, an average value calculation circuit for obtaining an average value of magnetic detection signals measured by the magnetic sensor, a dispersion calculation circuit for obtaining dispersion of the magnetic detection signal from the average value and the magnetic detection signal, and a dispersion. Coefficient calculation circuit for obtaining a coefficient that is the reciprocal of the value obtained by multiplying by, a reference signal waveform storage circuit that stores the previously obtained magnetic signal waveform of the target magnetic material as a reference signal waveform, and the inverse of the value obtained by doubling the variance. And the reference signal waveform, the likelihood ratio between the likelihood when the magnetic probe signal is only a noise signal due to geomagnetic fluctuations and the likelihood when the noise signal and the magnetic signal from the target magnetic material are mixed is obtained. Likelihood ratio calculation circuit, a selection circuit for selecting the threshold setting mode and the target magnetic material search mode with respect to the operating condition at the time of collecting the magnetic search signal, an average value calculation circuit for obtaining the average value of the likelihood ratio, and the likelihood. Likelihood from ratio and average It consists of a standard deviation calculation circuit that calculates the standard deviation of the degree ratio, a threshold setting circuit that calculates the threshold from the standard deviation and the average value, and a comparison circuit that compares the values of the threshold and the likelihood ratio. Sampled for a certain period of time, input this value to the above-mentioned average value calculation circuit to obtain the average value, then input this value and the sampled magnetic probe signal to the above-mentioned dispersion calculation circuit to obtain the dispersion, and further calculate this value to the above coefficient The reciprocal of the value obtained by doubling the variance is input to the circuit, and this value, the sampled magnetic probe signal, and the reference signal waveform from the reference signal waveform storage circuit are input to the likelihood ratio calculation circuit, and the likelihood ratio is calculated. , The threshold setting mode of the selection circuit is selected, the likelihood ratio output from the likelihood ratio calculation circuit is sampled for a certain period of time, and this is input to the average value calculation circuit to calculate the average value. The standard deviation of the values and sampled likelihood ratio is input to the standard deviation calculation circuit, further the average value and the value determining the threshold input to the threshold setting circuit. Next, when the target magnetic material search mode is selected by the selection circuit, the likelihood ratio which is the output from the likelihood ratio calculation circuit and the threshold value are input to the comparison circuit, and the likelihood ratio is calculated from the threshold value. The magnetic detection signal processor is characterized in that the target signal is automatically detected by setting the target detection when the value is large and not detecting the target when the value is not large.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11065995A JPH08304556A (en) | 1995-05-09 | 1995-05-09 | Magnetometric sensing signal processor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11065995A JPH08304556A (en) | 1995-05-09 | 1995-05-09 | Magnetometric sensing signal processor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08304556A true JPH08304556A (en) | 1996-11-22 |
Family
ID=14541240
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11065995A Pending JPH08304556A (en) | 1995-05-09 | 1995-05-09 | Magnetometric sensing signal processor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08304556A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1019505A (en) * | 1996-03-05 | 1998-01-23 | He Holdings Inc Dba Hughes Electron | Method and device for determining position of magnetic dipole which use spatial and temporal processing of magnetometer data |
| JPH1026506A (en) * | 1996-03-05 | 1998-01-27 | He Holdings Inc Dba Hughes Electron | Improved dipole moment detector and localizer |
| JP2013156225A (en) * | 2012-01-31 | 2013-08-15 | Shimadzu Corp | Magnetic detection system |
| JP2014106122A (en) * | 2012-11-28 | 2014-06-09 | Shimadzu Corp | Magnetic detection system |
-
1995
- 1995-05-09 JP JP11065995A patent/JPH08304556A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1019505A (en) * | 1996-03-05 | 1998-01-23 | He Holdings Inc Dba Hughes Electron | Method and device for determining position of magnetic dipole which use spatial and temporal processing of magnetometer data |
| JPH1026506A (en) * | 1996-03-05 | 1998-01-27 | He Holdings Inc Dba Hughes Electron | Improved dipole moment detector and localizer |
| JP2013156225A (en) * | 2012-01-31 | 2013-08-15 | Shimadzu Corp | Magnetic detection system |
| JP2014106122A (en) * | 2012-11-28 | 2014-06-09 | Shimadzu Corp | Magnetic detection system |
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