JP3682798B2

JP3682798B2 - Method and apparatus for exploring buried objects

Info

Publication number: JP3682798B2
Application number: JP01375096A
Authority: JP
Inventors: 勝綱崎; 隆菊田; 秀樹早川; 雅樹岸
Original assignee: Osaka Gas Co Ltd
Current assignee: Osaka Gas Co Ltd
Priority date: 1996-01-30
Filing date: 1996-01-30
Publication date: 2005-08-10
Anticipated expiration: 2016-01-30
Also published as: JPH09211145A

Description

【０００１】
【発明の属する技術分野】
本発明は、地中および建物などの隠蔽場所に埋設された埋設物を探査するための方法および装置に関する。
【０００２】
【従来の技術】
ガスなどを輸送する地中に埋設された管を、地上で探査するための地中探査レーダは、送信アンテナにパルス波を与えてパルス状の電磁波を地中に放射し、地中埋設管による反射波を受信アンテナで受信し、高周波増幅器で増幅し、こうして地中埋設管を地上で横切って走査することによって、地中埋設管を含む土壌の断面の画像を得ることができる。送信アンテナから地表面に電磁波を放射したとき、その地表面での反射波の振幅である強度は、地中埋設管からの反射波の強度に比べて、たとえば約２．５倍以上、たとえば４倍であって、はるかに大きい。したがって、このような地表面での反射が高周波増幅器に入力されると、その増幅器が飽和してしまい、この飽和後に増幅動作が回復するまでに時間がかかる。したがって地表面での反射波の後に、地中埋設管による微弱な反射波を充分に増幅することができなくなってしまう。
【０００３】
この問題を解決するために、送信アンテナによる電磁波の放射後から反射波を受信完了するまでの期間において、ダイナミックレンジ４０ｄＢの高周波増幅器の増幅度を、たとえば−５ｄＢから＋３５ｄＢまで時間経過に伴って大きくなるように変化することが考えられる。
【０００４】
電磁波の土壌中における減衰率は、一般の土壌では−１５ｄＢ／ｍであり、砂では−５ｄＢ／ｍであり、また粘土では−２５ｄＢ／ｍであり、したがって土壌の種類によってその減衰率が異なる。したがって前記増幅器の増幅度の時間経過に伴う変化を適切に選ぶことが困難である。したがって従来では、前記増幅度の時間経過に伴う変化を熟練者が複数回の探査によって試行錯誤的に設定して最適な増幅度を見つけている。したがって探査場所が交通量の多い道路である場合などでは、交通渋滞を起こすおそれがあり、また作業者が危険である。
【０００５】
他の先行技術は、特公平７−６９４３１に開示されている。この先行技術では、アンテナを走査する移動間隔Ｄ０（たとえば２ｃｍ）の間に、増幅度Ｇｉ（ｉ＝１〜５）を最初の増幅度Ｇ１から最終の増幅度Ｇ５まで合計５回、順次的に変化させ、各増幅度Ｇｉ毎に反射信号を１つずつ受信し、アンテナが総移動距離Ｌ０（たとえば３ｍ）に達するまで上記のステップをＬ０／Ｇ０回繰返し、増幅度Ｇｉ毎に受信された反射波信号に基づいて、横軸をアンテナ移動距離とし、縦軸を電磁波の送信から受信までの時間とした断面画像を合計５個作成し、反射波信号の振幅値が所定の振幅値以下となる波形の面積の各増幅度Ｇｉで各断面画像の面積に対する割合である白の占有率Ｒｗｉ（ｉ＝１〜５）を計算し、５個の断面画像のうち、前記計算値Ｒｗｉが所定の基準値をＲｗ０としたとき、Ｒｗｉ＜Ｒｗ０の関係を満たす断面画像が１つの場合、その断面画像を選択し、その画像を形成するのに使用した増幅度Ｇｉを最適増幅率として記録し、またＲｗｉ＜Ｒｗ０の関係を満たす断面画像が複数ある場合、それらの複数の断面画像のうち、地中断面画像に占める白色の占有率Ｒｗｉが前記所定の基準値Ｒｗ０に最も近い１つの断面画像を選んで、その画像を形成するのに使用した増幅度Ｇｉを最適増幅率として記録し、また前記関係を満たす地中断面画像がない場合、増幅度Ｇｉのうち、最大値に所定の値Ｇｘだけ大きい増幅度を最適増幅率として記録する。
【０００６】
【発明が解決しようとする課題】
この先行技術では、土壌に電磁波の放射後から反射波を受信するまでの期間における増幅器の増幅度を時間経過に伴って大きくなるように変化する工夫はなされておらず、一旦、設定した増幅度Ｇｉは、１つの地中断面画像を得るにあたり、一定のままに保たれ、したがって深さ方向の土壌による電磁波の減衰の変化に充分対応することができず、地中埋設物の探査を正確に行うことができない。
【０００７】
前述の先行技術の他の問題は、各増幅度Ｇｉを用いて得られた地中断面画像における白色領域の面積が占める占有率Ｒｗｉを用いており、換言すると、地中断面画像の２次元の演算を行っており、演算処理が複雑であり、時間がかかるという問題がある。
【０００８】
本発明の目的は、電磁波の放射後から反射波を受信完了するまでの期間における高周波増幅器の増幅度を時間経過に伴って大きくなるように変化して地表面などの隠蔽場所の表面による大きな振幅を有する反射波による悪影響を防ぐとともに、土壌などの隠蔽場所の電磁波の各種の減衰率に拘わらず、埋設物の正確な探査を自動的に可能にするとともに、その演算処理を簡略化することができるようにした地中埋設物の探査方法および装置を提供することである。
【０００９】
【課題を解決するための手段】
本発明は、埋設物が埋設されている隠蔽場所の表面に沿って移動しつつ、隠蔽場所に電磁波を放射し、
埋設物による反射波を受信し、
放射した電磁波と受信した反射波との時間差に基づいて隠蔽場所内の埋設物を探査する埋設物の探査方法において、
予め定める第１の距離Δｄだけ移動する間に、受信した反射波を、増幅度が時間経過に伴って大きくなるように変化する複数の増幅度・時間パターンで、増幅してメモリにストアし、
このメモリへのストア動作を、予め定める第２の距離Ｌ１にわたって繰返し、
前記各パターン毎に、隠蔽場所の表面からその表面近傍の予め定める深度ＤＰ１まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値を求め、
前記各パターン毎に、前記平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値の最大値と最小値とを求め、
各パターンのうち、最大値と最小値とが、増幅ダイナミックレンジ内で、飽和する程度Ｎ１２ｊが最小であるパターンを、最適なパターンとして選択し、
この最適なパターンで増幅してメモリにストアされた反射波のデータを用いて、埋設物を探査し、
飽和する程度Ｎ１２ｊは、前記最大値と前記最小値とが増幅ダイナミックレンジの飽和する値に等しい数Ｎ１ｊ，Ｎ２ｊの和であることを特徴とする埋設物の探査方法である。
また本発明は、最小の飽和する程度Ｎ１２ｊを有する前記パターンが複数存在するとき、前記最大値と前記最小値との差Ｐｊｚ１が最大であるパターンを、最適なパターンとして選択することを特徴とする。
また本発明は、最小の飽和する程度Ｎ１２ｊを有する前記パターンが複数存在するとき、前記各パターン毎に、隠蔽場所の表面から埋設物の存在する予め定める深度ＤＰ２まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の絶対値の平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値を求め、
反射波の深さ方向の予め定める強度分布と、前記各パターン毎の絶対値の前記平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値との近似した程度を評価し、
その評価の結果、各パターンのうち、近似した程度が最もよいパターンを最適なパターンとして選択し、
この最適なパターンで増幅してメモリにストアされた反射波のデータを用いて埋設物を探査することを特徴とする。
また本発明は、前記近似した程度の評価は、前記予め定める強度分布と、前記各パターン毎の絶対値の前記平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値との深さ方向の各位置毎の差の２乗の和またはその和に対応する値を演算して求めることを特徴とする。
また本発明は、埋設物が埋設されている隠蔽場所の表面に沿って移動しつつ、隠蔽場所に電磁波を放射し、
埋設物による反射波を受信し、
放射した電磁波と受信した反射波との時間差に基づいて隠蔽場所内の埋設物を探査する埋設物の探査方法において、
予め定める第１の距離Δｄだけ移動する間に、受信した反射波を、増幅度が時間経過に伴って大きくなるように変化する複数の増幅度・時間パターンで、増幅してメモリにストアし、
このメモリへのストア動作を、予め定める第２の距離Ｌ１にわたって繰返し、
前記各パターン毎に、隠蔽場所の表面からその表面近傍の予め定める深度ＤＰ１まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値を求め、
前記各パターン毎に、前記平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値の最大値と最小値とを求め、
各パターンのうち、最大値と最小値とが、増幅ダイナミックレンジ内で、飽和する程度Ｎ１２ｊが最小であるパターンを、最適なパターンとして選択し、
この最適なパターンで増幅してメモリにストアされた反射波のデータを用いて、埋設物を探査し、
最小の飽和する程度Ｎ１２ｊを有する前記パターンが複数存在するとき、前記最大値と前記最小値との差Ｐｊｚ１が最大であるパターンを、最適なパターンとして選択することを特徴とする埋設物の探査方法である。
また本発明は、埋設物が埋設されている隠蔽場所の表面に沿って移動しつつ、隠蔽場所に電磁波を放射し、
埋設物による反射波を受信し、
放射した電磁波と受信した反射波との時間差に基づいて隠蔽場所内の埋設物を探査する埋設物の探査方法において、
予め定める第１の距離トｄだけ移動する間に、受信した反射波を、増幅度が時間経過に伴って大きくなるように変化する複数の増幅度・時間パターンで、増幅してメモリにストアし、
このメモリへのストア動作を、予め定める第２の距離Ｌ１にわたって繰返し、
前記各パターン毎に、隠蔽場所の表面からその表面近傍の予め定める深度ＤＰ１まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値を求め、
前記各パターン毎に、前記平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値の最大値と最小値とを求め、
各パターンのうち、最大値と最小値とが、増幅ダイナミックレンジ内で、飽和する程度Ｎ１２ｊが最小であるパターンを、最適なパターンとして選択し、
この最適なパターンで増幅してメモリにストアされた反射波のデータを用いて、埋設物を探査し、
最小の飽和する程度Ｎ１２ｊを有する前記パターンが複数存在するとき、前記各パターン毎に、隠蔽場所の表面から埋設物の存在する予め定める深度ＤＰ２まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の絶対値の平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値を求め、
反射波の深さ方向の予め定める強度分布と、前記各パターン毎の絶対値の前記平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値との近似した程度を評価し、
その評価の結果、各パターンのうち、近似した程度が最もよいパターンを最適なパターンとして選択し、
この最適なパターンで増幅してメモリにストアされた反射波のデータを用いて埋設物を探査することを特徴とする埋設物の探査方法である。
また本発明は、埋設物が埋設されている隠蔽場所の表面に沿って移動しつつ、隠蔽場所に電磁波を放射し、
埋設物による反射波を受信し、
放射した電磁波と受信した反射波との時間差に基づいて隠蔽場所内の埋設物を探査する埋設物の探査方法において、
予め定める第１の距離Δｄだけ移動する間に、受信した反射波を、増幅度が時間経過に伴って大きくなるように変化する複数の増幅度・時間パターンで、増幅してメモリにストアし、
このメモリへのストア動作を、予め定める第２の距離Ｌ１にわたって繰返し、
前記各パターン毎に、隠蔽場所の表面から埋設物の存在する予め定める深度ＤＰ２まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の絶対値の平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値を求め、
反射波の深さ方向の予め定める強度分布と、前記各パターン毎の絶対値の前記平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値との近似した程度を評価し、
その評価の結果、各パターンのうち、近似した程度が最もよいパターンを最適なパターンとして選択し、
この最適なパターンで増幅してメモリにストアされた反射波のデータを用いて埋設物を探査することを特徴とする埋設物の探査方法である。
また本発明は、前記近似した程度の評価は、反射波の深さ方向の予め定める強度分布と、前記各パターン毎の前記平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値との深さ方向の各位置毎の差の２乗の和またはその和に対応する値を求めることを特徴とする。
また本発明は、埋設物が埋設されている隠蔽場所に電磁波を放射する手段と、
埋設物による反射波を受信するアンテナと、
アンテナの出力を増幅度可変で増幅する増幅手段と、
アンテナの移動距離を検出する手段と、
増幅度が、時間経過に伴って大きくなるように変化する相互に異なる複数の増幅度・時間パターンをストアする第１メモリと、
増幅手段の出力をストアする第２メモリと、
移動距離検出手段の出力に応答し、予め定める第１の距離Δｄだけ移動する間に、メモリにストアされている複数の各パターンで増幅手段の増幅度を変化して第２メモリにストアし、このストア動作を予め定める第２の距離Ｌ１にわたって繰返す増幅度制御手段と、
第２メモリのストア内容を読出して、前記各パターン毎に、隠蔽場所の表面からその表面近傍の予め定める深度ＤＰ１まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値を演算して求める第１演算手段と、
第１演算手段の出力に応答して、前記各パターン毎に、前記平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値の最大値と最小値とを演算して求める第２演算手段と、
第２演算手段の出力に応答し、各パターンのうち、最大値と最小値とが増幅手段の増幅ダイナミックレンジ内で、飽和する程度Ｎ１２ｊが最小であるパターンを最適なパターンとして選択する選択手段と、
この選択手段で選択された最適なパターンを用いて得られた第２メモリにストアされている反射波のデータを用いて埋設物を探査する手段とを含み、
選択手段は、前記飽和する程度Ｎ１２ｊを、前記最大値と前記最小値とが増幅ダイナミックレンジの飽和する値に等しい数Ｎ１ｊ，Ｎ２ｊの和に定めることを特徴とする埋設物の探査装置である。
また本発明は、選択手段は、最小の飽和する程度Ｎ１２ｊを有する前記パターンが複数存在するとき、前記最大値と前記最小値との差Ｐｊｚ１が最大であるパターンを、最適なパターンとして選択することを特徴とする。
また本発明は、選択手段は、最小の飽和する程度Ｎ１２ｊを有する前記パターンが複数存在するとき、前記各パターン毎に、隠蔽場所の表面から埋設物の存在する予め定める深度ＤＰ２まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の絶対値の平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値を求め、
反射波の深さ方向の予め定める強度分布と、前記各パターン毎の絶対値の前記平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値との近似した程度を評価し、
その評価の結果、各パターンのうち、近似した程度が最もよいパターンを最適なパターンとして選択し、
この最適なパターンで増幅してメモリにストアされた反射波のデータを用いて埋設物を探査することを特徴とする。
また本発明は、埋設物が埋設されている隠蔽場所に電磁波を放射する手段と、
埋設物による反射波を受信するアンテナと、
アンテナの出力を増幅度可変で増幅する増幅手段と、
アンテナの移動距離を検出する手段と、
増幅度が、時間経過に伴って大きくなるように変化する相互に異なる複数の増幅度・時間パターンをストアする第１メモリと、
増幅手段の出力をストアする第２メモリと、
移動距離検出手段の出力に応答し、予め定める第１の距離Δｄだけ移動する間に、メモリにストアされている複数の各パターンで増幅手段の増幅度を変化して第２メモリにストアし、このストア動作を予め定める第２の距離Ｌ１にわたって繰返す増幅度制御手段と、
第２メモリのストア内容を読出して、前記各パターン毎に、隠蔽場所の表面からその表面近傍の予め定める深度ＤＰ１まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値を演算して求める第１演算手段と、
第１演算手段の出力に応答して、前記各パターン毎に、前記平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値の最大値と最小値とを演算して求める第２演算手段と、
第２演算手段の出力に応答し、各パターンのうち、最大値と最小値とが増幅手段の増幅ダイナミックレンジ内で、飽和する程度Ｎ１２ｊが最小であるパターンを最適なパターンとして選択する選択手段と、
この選択手段で選択された最適なパターンを用いて得られた第２メモリにストアされている反射波のデータを用いて埋設物を探査する手段とを含み、
選択手段は、最小の飽和する程度Ｎ１２ｊを有する前記パターンが複数存在するとき、前記最大値と前記最小値との差Ｐｊｚ１が最大であるパターンを、最適なパターンとして選択することを特徴とする埋設物の探査装置である。
また本発明は、埋設物が埋設されている隠蔽場所に電磁波を放射する手段と、
埋設物による反射波を受信するアンテナと、
アンテナの出力を増幅度可変で増幅する増幅手段と、
アンテナの移動距離を検出する手段と、
増幅度が、時間経過に伴って大きくなるように変化する相互に異なる複数の増幅度・時間パターンをストアする第１メモリと、
増幅手段の出力をストアする第２メモリと、
移動距離検出手段の出力に応答し、予め定める第１の距離Δｄだけ移動する間に、メモリにストアされている複数の各パターンで増幅手段の増幅度を変化して第２メモリにストアし、このストア動作を予め定める第２の距離Ｌ１にわたって繰返す増幅度制御手段と、
第２メモリのストア内容を読出して、前記各パターン毎に、隠蔽場所の表面からその表面近傍の予め定める深度ＤＰ１まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値を演算して求める第１演算手段と、
第１演算手段の出力に応答して、前記各パターン毎に、前記平均値Ｐｊｚまたは平均値Ｐｊｚに対応する値の最大値と最小値とを演算して求める第２演算手段と、
第２演算手段の出力に応答し、各パターンのうち、最大値と最小値とが増幅手段の増幅ダイナミックレンジ内で、飽和する程度Ｎ１２ｊが最小であるパターンを最適なパターンとして選択する選択手段と、
この選択手段で選択された最適なパターンを用いて得られた第２メモリにストアされている反射波のデータを用いて埋設物を探査する手段とを含み、
選択手段は、最小の飽和する程度Ｎ１２ｊを有する前記パターンが複数存在するとき、前記各パターン毎に、隠蔽場所の表面から埋設物の存在する予め定める深度ＤＰ２まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の絶対値の平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値を求め、
反射波の深さ方向の予め定める強度分布と、前記各パターン毎の絶対値の前記平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値との近似した程度を評価し、
その評価の結果、各パターンのうち、近似した程度が最もよいパターンを最適なパターンとして選択し、
この最適なパターンで増幅してメモリにストアされた反射波のデータを用いて埋設物を探査することを特徴とする埋設物の探査装置である。
また本発明は、前記選択手段は、前記予め定める強度分布と、前記各パターン毎の絶対値の前記平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値との深さ方向の各位置毎の差の２乗の和またはその和に対応する値を演算して近似した程度を評価することを特徴とする。
また本発明は、埋設物が埋設されている隠蔽場所に電磁波を放射する手段と、
埋設物による反射波を受信するアンテナと、
アンテナの出力を増幅度可変で増幅する増幅手段と、
アンテナの移動距離を検出する手段と、
増幅度が、時間経過に伴って大きくなるように変化する相互に異なる複数の増幅度・時間パターンをストアする第１メモリと、
増幅手段の出力をストアする第２メモリと、
反射波の深さ方向の予め定める強度分布をストアする第３メモリと、
移動距離検出手段の出力に応答し、予め定める第１の距離Δｄだけ移動する間に、メモリにストアされている複数の各パターンで増幅手段の増幅度を変化して第２メモリにストアし、このストア動作を予め定める第２の距離Ｌ１にわたって繰返す増幅度制御手段と、
第２メモリのストア内容を読出して、前記各パターン毎に、隠蔽場所の表面から少なくとも埋設物が埋設されている近傍の予め定める深度ＤＰ２まで、深さ方向の各位置毎に第２の距離Ｌ１にわたって反射波の強度の絶対値の平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値を演算して求め、第４メモリにストアする第１演算手段と、
第３メモリにストアされている前記予め定める強度分布と、第４メモリから読出したストア内容とに基づき、前記予め定める強度分布と、前記各パターン毎の絶対値の前記平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値との近似した程度を評価する評価手段と、
評価手段の出力に応答し、各パターンのうち、近似した程度が最もよいパターンを最適なパターンとして選択する選択手段と、
選択手段で選択された最適なパターンを用いて得られた第２メモリにストアされている反射波のデータを用いて埋設物を探査する手段とを含むことを特徴とする埋設物の探査装置である。
また本発明は、前記評価手段は、前記予め定める強度分布と、前記各パターン毎の絶対値の前記平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値との深さ方向の各位置毎の差の２乗の和またはその和に対応する値を演算して求めることを特徴とする。
【００１０】
本発明に従えば、複数の増幅度・時間パターンを第１メモリにストアしておき、各増幅度・時間パターンで、受信した反射波を、高周波増幅器の増幅度が時間経過に伴って大きくなるように変化し、このような複数の各増幅度・時間パターンを用いた反射波の第２メモリへのストア動作を、予め定める第１の距離Δｄ（たとえば２ｃｍ）だけ移動する間に行い、このような動作を予め定める第２の距離Ｌ１（たとえば５ｍ）にわたって繰返す。複数の各増幅度・時間パターン毎に、隠蔽場所の表面からその表面近傍の予め定める深度ＤＰ１（たとえば５０ｃｍ）まで、深さ方向の各位置毎に第２距離Ｌ１にわたって反射波の強度の平均値Ｐｊｚまたはそれに対応する値を求める。
隠蔽場所の表面から深度ＤＰ１までの範囲では、地表面などの隠蔽場所の表面による反射波の振幅が大きく、したがって受信アンテナからの反射波を増幅する高周波増幅器が飽和してしまうおそれが大きい。そこで本発明に従えば、上述の平均値Ｐｊｚまたはそれに対応する値の最大値と最小値とを各増幅度・時間パターン毎に求めて、それらの最大値と最小値とが増幅器の増幅ダイナミックレンジ内で、飽和する程度Ｎ１２ｊが最小である増幅度・時間パターンを、最適なパターンとして選択し、こうして選択した最適な増幅度・時間パターンを用いて埋設物の探査を行う。
前記飽和する程度Ｎ１２ｊは、最大値と最小値とが増幅ダイナミックレンジの飽和する値に等しい数Ｎ１ｊ，Ｎ２ｊの和であってもよい。最小の飽和する程度Ｎ１２ｊを有する前記パターンが複数存在するとき、それらの複数のパターンのうち、最大値と最小値との差Ｐｊｚ１が最大であるパターンを最適なパターンとして選択し、これによって増幅ダイナミックレンジの可及的に全域を利用して、その増幅度を大きくすることができる。
最小の飽和する程度Ｎ１２ｊを有する前記パターンが複数存在するとき、隠蔽場所の表面から少なくとも埋設物が埋設されている近傍の予め定める深度ＤＰ２（たとえば１ｍまたは２ｍ）まで、深さ方向の各位置毎に第２距離Ｌ１にわたって反射波の強度の絶対値の平均値Ｑｊｚまたはそれに対応する値を演算して求め、反射波の深さ方向の予め定める強度分布と、前記各パターン毎の絶対値の前記平均値Ｑｊｚまたは平均値Ｑｊｚに対応する値との近似した程度を評価し、その評価の結果、各パターンのうち、近似した程度の最もよいパターンを最適なパターンとして選択し、この最適なパターンで増幅してメモリにストアされた反射波のデータを用いて埋設物を探査する。この近似した程度を評価するにあたっては、最小２乗法の手法を用いてもよい。
複数の各増幅度・時間パターンで反射波を増幅して第２メモリにストアする動作は、第１の距離Δｄ内において予め定める距離だけ変位するたびに、各パターンでの増幅およびストア動作を繰返してもよく、または隠蔽場所の同一位置において複数の増幅度・時間パターンを用いた増幅およびストア動作を繰返してもよく、この第１の距離Δｄだけ移動する間に、埋設物の表面の位置に拘わらず、上述の複数の各増幅度・時間パターンでの増幅およびストア動作を行えばよい。
こうして本発明に従えば、隠蔽場所の表面で電磁波の放射による反射波の受信動作を１回の走査で自動的に最適な増幅度・時間パターンを見つけることができる。したがってその探査場所が交通量の多い道路などであっても、探査作業を短時間に終了することができ、交通に支障をきたすことはなく、また作業者の安全が確保されることになる。しかも反射波の強度分布を走査方向に平均値Ｐｊｚまたはそれに対応する値を演算して求め、深さ方向の１次元分布を求めて最適な増幅度・時間パターンを見つけるための判別を行うようにし、その判別動作を簡素化することができ、演算処理が短時間で行うことができる。
さらに本発明に従えば、第２メモリにストアされている複数の各増幅度・時間パターン毎の反射波のストア内容を読出して、隠蔽場所の表面から少なくとも埋設物が埋設されている近傍の予め定める深度ＤＰ２（たとえば１ｍまたは２ｍ）まで、深さ方向の各位置毎に第２距離Ｌ１にわたって反射波の強度の絶対値の平均値Ｑｊｚまたはそれに対応する値を演算して第４メモリにストアする。第３メモリには、反射波の深さ方向の基準となる予め定める強度分布をストアしておく。
評価手段は、この第３メモリにストアされている強度分布と、第４メモリから読出したストア内容とに基づいて、複数の各増幅度・時間パターン毎に、両者の近似した程度を評価し、近似した程度が最もよい増幅度・時間パターンを最適なパターンとして選択する。その選択した増幅度・時間パターンを用いて、埋設物の探査を行う。評価手段による評価の手法としては、たとえば最小２乗法などを用いることができる。これによって反射波の強度分布を深さ方向の１次元分布にすることによって最適な増幅度・時間パターンを見つける演算を簡素化することができる。
【００１１】
【発明の実施の形態】
図１は、本発明の実施の一形態の地中埋設物の探査装置の全体の構成を簡略化して示すブロック図である。土壌５には、ガスなどの流体を輸送する鋼管などの埋設物である管６が埋設されている。地上では、この管６の探査を行うために、送信アンテナ７には、パルサ８から、図２（１）に示されるたとえば１００ＭＨｚ〜１０００ＭＨｚのパルスが高圧電源９の電力を用いて与えられる。送信アンテナ７から放射された電磁波は、矢符１０に示されるように進み、管６によって反射され、その反射波は参照符１１に示されるように進んで、もう１つの受信アンテナ１２で受信され、図２（２）に示される出力が受信アンテナ１２から得られる。送信アンテナ７から電磁波が放射され、受信アンテナ１２によって反射波が受信されるまでの時間差ΔＴは土壌５の表面と管６との深さ方向の距離、すなわち深度、および土壌の種類、したがってその土壌の減衰率に対応している。
【００１２】
送信アンテナ７と受信アンテナ１２とを一体的に固定して、図１の矢符１３で示されるように、地中埋設管６を横切るように移動することによって、管６を含む土壌５の鉛直面内での断面の原画像を得ることができる。これらのアンテナ７，１２の移動距離は、距離センサ１４によって検出される。距離センサは、その移動方向１３であるｘ方向に２ｃｍ移動する毎に１パルスを発生し、このパルスをマイクロコンピュータなどによって実現される処理回路１５で計数することによって、その走査距離を演算して求めることができる。
【００１３】
同期信号発生回路１６は、たとえば５００ｋＨｚのクロック信号を発生し、パルサ８は、送信アンテナ７に、たとえば５０ｋＨｚのパルスを与え、したがって各パルスの時間間隔Ｗ１は２０μｓｅｃである。受信アンテナ１２に接続される受信回路１７において、受信アンテナ１２の出力は、増幅手段Ｕ１に与えられる。増幅手段Ｕ１は、減衰器ＡＴＴ１とそれに後続して縦続接続される高周波増幅器ＡＭＰ１とから成る。
【００１４】
増幅手段Ｕ１の入出力間の増幅度は、図３に示されるように、土壌５の深さ方向、したがって時間経過に伴って、たとえば−５ｄＢ〜＋３５ｄＢに時間経過に伴って増加するように変化される。増幅器ＡＭＰ１の増幅度は、予め定める一定の値、すなわちこの実施の形態では４０ｄＢに保たれる。減衰器ＡＴＴ１の減衰率は、−４５ｄＢから−５ｄＢに時間経過に伴って小さくなるように変化される。これによって上述のようにユニットＵ１では、図３に示される増幅度の特性が得られる。こうして各増幅器ＡＭＰ１は、Ｓ／Ｎ比が良好であるダイナミックレンジ約４０ｄＢとなる。これによって土壌５に埋設されている管６の微弱な反射波を、大きな増幅度で増幅してライン１８に導出することが初めて可能になる。
【００１５】
減衰器ＡＴＴ１が時間経過に伴って図３に示される増幅度に対応した減衰率が時間経過に伴って小さくなるように変化する特性を達成するために、リードオンリメモリＭ１が設けられ、このストア内容は、カウンタ１９からの読出しパルスに応じて読出され、デジタル／アナログ変換器ＤＡ１によってアナログ信号に変換され、減衰器ＡＴＴ１に与えられる。この減衰器ＡＴＴ１は、前述のようにたとえば電界効果トランジスタによって実現され、そのゲートに減衰率に対応した電圧が時間経過に伴って変化して与えられ、またはバイポーラトランジスタによって実現される場合、そのベースに減衰率に対応した電圧が与えられる。
【００１６】
カウンタ１９には、同期信号発生回路１６からのパルサ８に与えられる信号に同期したたとえば５００ｋＨｚのパルスが図２（３）に示されるように与えられる。
【００１７】
サンプラ２１は、受信回路１７からライン１８を介する増幅手段Ｕ１の増幅器ＡＭＰ１からライン１８を介する信号が与えられ、図２（４）に示されるサンプリングパルスによってサンプリングされる。このサンプリングパルスは、ライン２２を介して同期信号発生回路１６から与えられる。
【００１８】
増幅手段Ｕ１の増幅度の時間経過は、図２（５）に示されるとおりであり、これによってその増幅手段Ｕ１の増幅器ＡＭＰ１からライン１８に導出される波形は、図２（２）に示される受信アンテナ１２の受信出力のうち、受信初期の波形の振幅が抑制されて大きな減衰率で減衰され、図２（６）のように大きい深度の反射の振幅が大きな増幅度で増幅される。
【００１９】
サンプラ２１の出力はフィルタ２５で濾波され、アナログデジタル変換器２６でデジタル信号に変換され、処理回路１５に与えられる。同期信号発生回路１６の出力は低周波同期信号発生回路２７に与えられ、カウンタ１９の同期動作が行われて、送信アンテナ７による電磁波の放射の時間Ｗ１毎にリセットされ、このライン２８からの低周波同期信号１ｋＨｚは、処理回路１５に与えられる。こうして処理回路１５では、サンプラ２１によってサンプリングされた反射波信号によって、地中埋設管６の深度を含む土壌５の鉛直断面の画像を正確に得ることができる。
【００２０】
減衰器ＡＴＴ１と増幅器ＡＭＰ１との組合せから成る増幅手段Ｕ１は、増幅器ＡＭＰ１の熱雑音などに起因したＳ／Ｎ比を良好に保ち、しかも地表面による大きな振幅を有する反射波を大きな減衰率で減衰させるとともに、地中埋設管６による微弱な反射波を大きな増幅度で増幅することができる。
【００２１】
受信回路１７によって受信されてサンプラ２１によってサンプリングされ、フィルタ２５およびアナログデジタル変換器２６を経て得られた土壌５の断面画像は、メモリＭ２にストアされ、この画像は図４に示されている。参照符３１は土壌５の表面を示し、像３２は、地中埋設管６の頂部付近を表している。図４の左右方向は走査方向１３であるｘ方向に一致し、図４の上下方向は土壌５の地表面３１からの深さ方向であるｚ方向に対応する。
【００２２】
図５は、図４に示される画像のｘ方向の各走査位置における深さ方向の反射波の受信強度をそれぞれ示している。図５（１）に示されるように反射波の振幅、すなわち強度は、０階調である最小値Ａと２５５階調である最大値Ｂの範囲の合計２５６階調で表される。反射波の最大値３３は階調の最大値Ｂで飽和しており、すなわち増幅器ＡＭＰ１が飽和したことを示している。また反射波の波形３４は、階調の最小値Ａで飽和しており、すなわち増幅器ＡＭＰ１が飽和していることを表している。このような図５（１）に示される反射波の深さ方向の強度は、増幅器ＡＭＰ１を飽和させ、その増幅手段Ｕ１における増幅度・時間パターンは後述のように不適切なものとして判別される。
【００２３】
メモリＭ２にストアされている画像の他の走査位置における深さ方向の強度は、図５（２）に示されている。この強度の最大値３５と最小値３６とは、最大値Ｂと最小値Ａの近傍であって、予め定める値の範囲Ｂ１，Ｂ２，Ａ１，Ａ２の範囲内にあり、したがって増幅器ＡＭＰ１の増幅機能を充分利用しており、したがって管６による微小な反射波を大きな増幅度で増幅することができる。このような図５（２）の反射波強度分布が得られたときの増幅度・時間パターンは、最適なものとして後述のように選ばれる。
【００２４】
図６は、処理回路１６の動作を説明するためのフローチャートである。距離センサ１４の出力に応答し、予め定める第１の距離Δｄ（たとえば２ｃｍ）だけｘ方向１３に移動する間に、メモリＭ１にストアされている複数ｎ（たとえば５）の増幅度・時間パターンで増幅手段Ｕ１の増幅度を変化して図４に示される画像が、ｘ方向１３に第２の距離Ｌ１（たとえば５ｍ）にわたって繰返されて図４に示される画像が、各増幅度・時間パターン毎にメモリＭ２にストアされる。
【００２５】
この動作は、図６のステップａ１〜ａ８を実行することによって達成される。ステップａ１からステップａ２に移り、メモリＭ１にストアされている合計ｎ（この実施の態様では５）の増幅度・時間パターンＳＴＣｉ（ｉ＝１〜ｎ）のうちの１つＳＴＣ１が選択され、ステップａ３では、その増幅度・時間パターンＳＴＣ１を用いた画像が、図７（１）の参照符Ｆ（１，１）に示されるようにして得られる。ステップａ４では、ｉだけインクリメントし、ステップａ５においてｉ＞ｎでなければ、再びステップａ３に移り、次の増幅度・時間パターンＳＴＣ２を用いて図７（２）に示される反射波の深さ方向の分布Ｆ（２，１）が得られる。同様にして、図７（３）〜図７（５）のように増幅度・時間パターンＳＴＣ３，ＳＴＣ４，ＳＴＣ５を用いてｘ方向１３の第１の距離Δｄだけ移動する間に、反射波の深さ方向の分布Ｆ（３，１），Ｆ（４，１），Ｆ（５，１）が得られる。
【００２６】
ステップａ６において送受信のアンテナ７，１２が距離Δｄ以上移動したことが距離センサ１４によって検出されると、次のステップａ７に移り、予め定める距離Ｌ１だけ移動したかどうかが判断され、そうでなければ再びステップａ２に戻って同じ動作が繰返されて、次のｘ方向１３の位置では反射波の強度分布Ｆ（１，２），Ｆ（２，２），Ｆ（３，２），Ｆ（４，２），Ｆ（５，２）が同様にして得られる。以下、同様な動作が繰返される。ここで、
Ｌ１＝ｍ・Δｄ …（１）
本発明の実施の一形態では、上述のようにＬ１＝５ｍであり、Δｄ＝２ｃｍであり、したがってｍ＝２５０である。こうしてメモリＭ２には、図７に示されるｘ方向１３の各位置での反射波の深さ方向の強度の分布Ｆ（１，１）〜Ｆ（５，２５０）がメモリＭ２にストアされる。
【００２７】
図８は、処理回路１５における図６に後続する動作を説明するためのフローチャートである。この図８では、複数ｎの各増幅度・時間パターン毎に、地表面３１からその地表面３１の近傍の予め定める深度ＤＰ１（たとえば５０ｃｍ）まで、深さ方向、すなわちｚ方向の各位置毎に第２距離Ｌ１にわたって反射波の強度の平均値Ｐｊｚを演算して求める。この動作は図８のステップｂ１〜ｂ７において達成され、さらにその各増幅度・時間パターン毎に、前記平均値Ｐｊｚの最大値Ｐｊｚｍａｘとそのｚ方向の個数とを求めるとともに、最小値Ｐｊｚｍｉｎとそのｚ方向の個数とを求める。この複数の各増幅度・時間パターン毎の最大値と最小値に関する演算は、ステップｂ８，ｂ９を実行することによって達成される。
【００２８】
図８のステップｂ１からステップｂ２に移り、複数ｎの増幅度・時間パターンＳＴＣ１〜ＳＴＣｎのうち、先ずｊ＝１として次のステップｂ３では、増幅度・時間パターンＳＴＣ１に対応するｎ個のデータである深さ方向の強度分布Ｆ（１，１）〜Ｆ（１，２５０）を、地表面から深度ＤＰ１まで、メモリＭ２から読出す。次のステップｂ４では、深さ方向であるｚ方向における位置を、ｚ＝１として設定し、次のステップｂ５において平均値Ｐｊｚを演算して求める。
【００２９】
【数１】

【００３０】
上述の式２において、ｇ（ｘ，ｚ）は、各強度分布Ｆ（１，１）〜Ｆ（１，２５０）の各波形を示している。
【００３１】
ステップｂ５において式２によって平均値Ｐｊｚを求めた後には、次のステップｂ６においてｚを１だけインクリメントして深さ方向の次の位置を設定し、ステップｂ７において深度ＤＰ１を超えていないこと（すなわちｚ＞ＤＰ１が成立しないこと）が判断されると、再びステップｂ５に移り、同様な動作を繰返し、こうして平均値Ｐｊｚを、深さ方向の各位置毎に演算して求める。
【００３２】
そこで次にステップｂ８では、各平均値Ｐｊｚ毎の最大値Ｐｊｚｍａｘと、その深さ方向であるｚ方向の個数を求める。またステップｂ９では、各平均値Ｐｊｚの最小値Ｐｊｚｍｉｎを求めるとともに、その最小値Ｐｊｚｍｉｎが深さ方向の個数を求める。こうして次のステップｂ１０では、ｊを１だけインクリメントし、ｊ＞ｎでなければステップｂ３に戻り、こうして複数ｎの全ての増幅度・時間パターンＳＴＣ１〜ＳＴＣ５毎に平均値Ｐｊｚの最大値とその個数とを求めるとともに、最小値とその個数を求める。このようにして表１が得られ、メモリＭ２ａにストアされる。
【００３３】
【表１】

【００３４】
処理回路１５は次に、図９に示される動作を実行する。この図９では、メモリＭ２ａにストアされている表１の内容を読出して、複数ｎの各増幅度・時間パターンＳＴＣ１〜ＳＴＣ５のうち、最大値と最小値とが増幅手段Ｕ１の増幅ダイナミックレンジ、たとえば４０ｄＢ内にありかつその増幅ダイナミックレンジ内の広い範囲にわたって存在するかどうかを判別し、これによって最適な増幅度・時間パターンの１つを選択し、これは前述の図５（２）の深さ方向の反射波の強度分布に対応している。
【００３５】
図９のステップｃ１からステップｃ２に移り、複数ｎのうちの増幅度・時間パターンＳＴＣ１〜ＳＴＣ５のうちの１つをｊ＝１として設定する。ステップｃ３では、表１の最大値Ｐｊｚｍａｘが最大階調である強度２５５である数Ｎ１ｊを計数するとともに、最小値Ｐｊｚｍｉｎが最小階調である強度零である数Ｎ２ｊを計数して求める。そこで
Ｎ１ｊ＋Ｎ２ｊ＝Ｎ１２ｊ …（３）
を演算して求める。この加算した値Ｎ１２ｊは、増幅器の増幅する程度を表す。
【００３６】
ステップｃ４では、最大値Ｐｊｚｍａｘと最小値Ｐｊｚｍｉｎとの差Ｐｊｚ１を演算して求める。
【００３７】
Ｐｊｚｍａｘ−Ｐｊｚｍｉｎ＝Ｐｊｚ１ …（４）
ステップｃ５では、ｊを１だけインクリメントして次の増幅度・時間パターンＳＴＣｊを設定し、このような動作をステップｃ６においてｊ＞ｎになるまで繰返して、複数ｎの全ての増幅度・時間パターンＳＴＣ１〜ＳＴＣｎについて繰返す。
【００３８】
ステップｃ７では、前述のステップｃ３で式３によって演算して得られた和Ｎ１２ｊが最小であるパターンＳＴＣｊを選択し、ステップｃ８において、その選択されたパターンＳＴＣｊが単一個であれば、その選択されたパターンＳＴＣｊを最適なパターンとして選択する。ステップｃ８において、最小の和Ｎ１２ｊを有するパターンＳＴＣｊが複数存在するとき、ステップｃ９に移り、それらの選択された複数のパターンＳＴＣｊの中から、前述のステップｃ４において式４に基づいて得られた差Ｐｊｚ１が最大であるパターンＳＴＣｊを、最適なパターンとして選択する。
【００３９】
こうして得られた最適な増幅度・時間パターンＳＴＣｊを用いた土壌５の断面像を用いて、地中埋設管６の探査を処理回路１５において行う。なお土壌５における地中埋設管６は、その形状が比較的小さく、したがって前述の平均値Ｐｊｚに悪影響を及ぼすものではない。
【００４０】
本発明の実施の他の形態においては、平均値Ｐｊｚに代えて、それに対応する値を求めるようにしてもよい。
【００４１】
本発明の実施の他の態様を図１０〜図１４を参照して説明する。図１０は、前述の図６によって得られるメモリＭ２にストアされている土壌５の断面画像である。本発明の実施の態様では、メモリＭ３に反射波の深さ方向の予め定める強度分布を図１１に示されるようにしてストアしておく。この基準となる強度分布は、反射波の強度の絶対値であり、土壌５の電磁波の減衰率に対応した特性を有し、実験によって予め定めておく。前述の図５に示されるように、走査方向１３の各位置における反射波の強度は、図１２（１）に示されており、その絶対値は、いわば全波整流した波形となって図１２（２）に示されるようにして得られる。こうして得られた図１２（２）の絶対値の平均値Ｑｊｚが、図１１に示される基準となる強度分布に近似している程度を評価し、その近似した程度が最も高い増幅度・時間パターンを最適なパターンとして選択する。このような動作は、図１３および図１４に示される処理回路１５によって達成されるフローチャートに示されている。図１３を参照して、ステップｄ１からステップｄ２に移り、このステップｄ２では、前述の図６に示される動作が達成され、メモリＭ２には、図７に示されるように複数ｎの各増幅度・時間パターンＳＴＣ１〜ＳＴＣｎ毎に、第１の距離Δｄだけ移動する間に、増幅手段Ｕ１の増幅度を変化した強度分布Ｆ（１，１）〜Ｆ（５，２５０）がストアされる。
【００４２】
ステップｄ３では、複数ｎの増幅度・時間パターンＳＴＣ１〜ＳＴＣｎの１つを設定するためにｊ＝１とし、この設定されたパターンＳＴＣｊに対応するデータである強度分布、たとえばｊ＝１のとき、Ｆ（１，１）〜Ｆ（１，２５０）を、地表面３１から深度ＤＰ２まで読出す。この深度ＤＰ２は、ＤＰ２＝ＤＰ１であってもよく、たとえば１ｍまたは２ｍなどの予め定める値であってもよい。
【００４３】
ステップｄ５では、図１２（１）に示される深さ方向の強度分布に基づいて、反射波の強度の絶対値を図１２（２）に示されるようにして求め、この絶対値を、ｘ方向１３の位置と深さ方向であるｚ方向の位置とに対応してｆ（ｘ，ｚ）で表すことにする。
【００４４】
ステップｄ６では、深さ方向の位置をｚ＝１として設定し、その反射波の強度の絶対値ｆ（ｘ，ｚ）の平均値Ｑｊｚを求める。
【００４５】
【数２】

【００４６】
ステップｄ８では、ｚを１だけインクリメントして深さ方向の次の位置を設定し、ステップｄ９において深度ＤＰ２を超えないとき（ｚ＞ＤＰ２でないとき）、ステップｄ７に戻って演算を繰返す。こうして深さ方向の各位置毎に、第２距離Ｌ１にわたって反射波の強度の絶対値ｆ（ｘ，ｚ）の平均値Ｑｊｚを演算して求め、その演算して求めた結果を、メモリＭ４にストアする。
【００４７】
ステップｄ１０では、前記平均値ＱｊｚとメモリＭ３にストアされている図１１に示される基準となる強度分布ｆｐ（ｚ）との近似した程度を評価するために、値ΔＦｊを計算する。
【００４８】
【数３】

【００４９】
ステップｄ１１では、ｊを１だけインクリメントし、他の増幅度・時間パターンを設定し、そのｊがｎを超えていないとき（すなわちｊ＞ｎでないとき）、ステップｄ１に戻る。こうして複数ｎの各増幅度・時間パターンＳＴＣ１〜ＳＴＣｎ毎に、上述の動作を繰返し、偏差ΔＦｊを求める。この偏差ΔＦｊは、深さ方向の各位置毎の平均値Ｑｊｚと基準となる強度分布ｆｐ（ｚ）との差の２乗の和であって、最小２乗法の手法で得られる値である。
【００５０】
こうして得られた偏差ΔＦｊを、図１４の動作によって演算し、最適な増幅度・時間パターンを選択する。図１４のステップｅ１からステップｅ２に移り、複数ｎの各増幅度・時間パターンＳＴＣ１〜ＳＴＣｎ毎の偏差ΔＦ１〜ΔＦｎのうちの最小値を選択する。そこでステップｅ３では、その最小値である偏差ΔＦｊが得られた増幅度・時間パターンＳＴＣｊを最適なものとして選択する。
【００５１】
この発明の実施の形態においても、土壌５に埋設されている管６は、土壌５の走査されるｘ方向１３に沿う長さは比較的短く、したがって前述の平均値Ｑｊｚに悪影響を及ぼすことはない。上述の実施の形態では、最小２乗法を用いて式６に従って平均値Ｑｊｚと基準となる強度分布ｆｐ（ｚ）との近似した程度の評価を行ったけれども、本発明の実施の他の形態では、その他の手法で近似した程度の評価を行うようにしてもよい。
【００５２】
前述の図９のステップｃ９の動作に代えて、図１３および図１４の動作が行われるようにしてもよい。すなわち図９のステップｃ８において、最小の和Ｎ１２ｊを有するパターンＳＴＣｊが複数存在するとき、図１３のステップｄ３〜ｄ１３が実行され、その後、図１４のステップｅ１〜ｅ４が実行されるように構成されてもよい。
【００５３】
本発明の実施のさらに他の形態として、平均値Ｑｊｚに代えて、その平均値Ｑｊｚに対応する値を演算して求めるようにしてもよい。
【００５４】
本発明は、土壌中の埋設物を探査するだけでなく、その他、たとえば建物および水中などにおける埋設物の探査のためなどの広範囲に実施することができる。
【００５５】
また送信アンテナ７と受信アンテナ１２とは兼用されてもよい。
【００５６】
【発明の効果】
本発明によれば、埋設物が埋設されている隠蔽場所への電磁波の放射後から電磁波を受信完了するまでの時間経過に伴って増幅度が大きくなるように変化する相互に異なる複数の増幅度・時間パターンを用い、アンテナの移動距離を検出する手段からの記録に応答して予め定める第１の距離ΔＤだけ移動する間に、各増幅度・時間パターン毎に増幅手段の出力をストアし、この動作を第２の距離Ｌ１にわたって繰返して行い、複数の各増幅度・時間パターン毎における隠蔽場所の表面からその表面近傍の予め定める深度ＤＰ１まで、深さ方向の各位置毎に第２距離Ｌ１にわたって電磁波の強度の平均値Ｐｊｚまたはこれに対応する値を演算して求めて、それらの各パターン毎の最大値と最小値が増幅手段の増幅ダイナミックレンジ内で、飽和する程度Ｎ１２ｊが最小である増幅度・時間パターンを最適なパターンとして選択し、これによって増幅手段の飽和を防ぎ、しかも増幅手段の増幅機能を充分に達成して埋設物による微弱な反射波を大きな増幅度で増幅することを可能にする。
【００５７】
しかも本発明によれば、隠蔽場所の１回の走査で、最適な増幅度・時間パターンを見つけることができ、作業性が良好であり、したがって交通量が多い道路などにおいて交通の支障を起こすことはなく、また作業者が安全である。
【００５８】
さらに本発明によれば、増幅手段の出力である反射波の強度分布を隠蔽場所の表面に沿う走査方向に平均値Ｐｊｚを求めて、深さ方向の１次元分布にすることによって最適な増幅度・時間パターンの選択を容易にし、これによって演算処理を簡素化し、その演算処理時間を短縮することができる。
【００５９】
また本発明によれば、増幅手段によって得られた反射波の出力を、隠蔽場所の表面から少なくとも埋設物が埋設されている近傍の予め定める深度ＤＰ２まで、深さ方向の各位置毎に第２距離Ｌ１にわたって反射波の強度の絶対値の平均値Ｑｊｚまたはそれに対応する値を演算して求め、こうして得られた平均値Ｑｊｚまたはそれに対応する値と、反射波の深さ方向の基準となる予め定める強度分布との近似の程度を評価し、近似した程度が最もよい、すなわち近似の程度が高い増幅度・時間パターンを最適なパターンとして選択するようにしたので、上述と同様な効果が達成され、簡便な作業で演算処理を簡略化し、高精度の埋設物の探査を達成することが可能になる。
【図面の簡単な説明】
【図１】本発明の実施の一形態の全体の構成を簡略化して示すブロック図である。
【図２】図１に示される実施の一形態の動作を説明するための波形図である。
【図３】図１の実施の一形態における受信回路１７における増幅手段Ｕ１の特性を示すグラフである。
【図４】土壌５の断面画像を示す図である。
【図５】土壌５の地表面３１が走査されるｘ方向１３の或る１つの位置における深さ方向の反射波の強度分布を示す図である。
【図６】予め定める第１の距離Δｄだけｘ方向に走査して移動する間に、メモリＭ１にストアされている複数ｎの各増幅度・時間パターンＳＴＣ１〜ＳＴＣｎで増幅手段Ｕ１の増幅度を変化して第２メモリＭ２にストアし、このストア動作を予め定める第２の距離Ｌ１にわたって繰返す動作を説明するためのフローチャートである。
【図７】複数ｎの各増幅度・時間パターン毎の深さ方向の強度分布Ｆ（１，１）〜（５〜２５０）を示す図である。
【図８】複数ｎの各増幅度・時間パターン毎に、土壌５の地表面３１からその地表面近傍の予め定める深度ＤＰ１まで、深さ方向の各位置毎に第２距離Ｌ１にわたって反射波の強度の平均値Ｐｊｚを演算し、さらにその最大値と最小値などを求める動作を説明するためのフローチャートである。
【図９】複数ｎの各増幅度・時間パターンＳＴＣ１〜ＳＴＣｎのうち、前述の最大値と最小値とが増幅手段Ｕ１の増幅ダイナミックレンジ内に有り、かつその増幅ダイナミックレンジのほぼ全域にわたるパターンを最適なパターンとして選択するための動作を説明するためのフローチャートである。
【図１０】本発明の実施の他の形態のメモリＭ２にストアされる土壌５の断面画像を示す図である。
【図１１】メモリＭ３にストアされる反射波の深さ方向の予め定める基準となる強度分布を示す図である。
【図１２】反射波の強度の絶対値を説明するための図である。
【図１３】処理回路１５によって、メモリＭ３にストアされている予め定める強度分布ｆｐと絶対値の平均値Ｑｊｚとの偏差ΔＦｊを、複数ｎの各増幅度・時間パターンＳＴＣ１〜ＳＴＣｎ毎に演算して求める動作を説明するためのフローチャートである。
【図１４】処理回路１５によって、前記偏差ΔＦｊであることによって、近似した程度が最も良い増幅度・時間パターンＳＴＣ１〜ＳＴＣｎを最適なパターンとして選択する動作を説明するためのフローチャートである。
【符号の説明】
５土壌
６管
７送信アンテナ
８パルサ
９高圧電源
１２受信アンテナ
１４距離センサ
１５処理回路
１７受信回路
１８，２２ライン
１９カウンタ
２１サンプラ
ＡＴＴ１減衰器
ＡＭＰ１高周波増幅器
ＤＡ１デジタル／アナログ変換器
Ｕ１増幅手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for exploring buried objects buried in concealed places such as underground and buildings.
[0002]
[Prior art]
An underground exploration radar for exploring pipes buried in the ground that transport gas etc. on the ground emits pulsed electromagnetic waves into the ground by applying a pulse wave to the transmitting antenna, and uses underground pipes The reflected wave is received by the receiving antenna, amplified by the high-frequency amplifier, and thus the underground pipe is scanned across the ground, thereby obtaining an image of a cross section of the soil including the underground pipe. When electromagnetic waves are radiated from the transmitting antenna to the ground surface, the intensity, which is the amplitude of the reflected wave on the ground surface, is, for example, about 2.5 times or more, for example, 4 compared to the intensity of the reflected wave from the underground tube. Double and much bigger. Therefore, when such reflection on the ground surface is input to the high-frequency amplifier, the amplifier is saturated, and it takes time until the amplification operation is restored after the saturation. Therefore, after the reflected wave on the ground surface, the weak reflected wave from the underground pipe cannot be sufficiently amplified.
[0003]
In order to solve this problem, the amplification factor of the high-frequency amplifier having a dynamic range of 40 dB increases, for example, from −5 dB to +35 dB over time in a period from when the electromagnetic wave is radiated by the transmitting antenna to when reception of the reflected wave is completed. It is conceivable to change as follows.
[0004]
The attenuation rate of electromagnetic waves in soil is -15 dB / m for general soil, -5 dB / m for sand, and -25 dB / m for clay. Therefore, the attenuation rate varies depending on the type of soil. Therefore, it is difficult to appropriately select a change with time of the amplification degree of the amplifier. Therefore, in the past, a skilled person finds an optimum amplification degree by setting a change of the amplification degree with time through trial and error by a plurality of searches. Therefore, when the exploration site is a road with a lot of traffic, there is a risk of traffic congestion and the worker is dangerous.
[0005]
Another prior art is disclosed in Japanese Patent Publication No. 7-69431. In this prior art, during the movement interval D0 (for example, 2 cm) for scanning the antenna, the amplification degree Gi (i = 1 to 5) is sequentially increased five times from the first amplification degree G1 to the final amplification degree G5. Change, receive one reflection signal for each amplification degree Gi, repeat the above steps L0 / G0 times until the antenna reaches the total moving distance L0 (for example, 3 m), and the reflection received for each amplification degree Gi Based on the wave signal, a total of five cross-sectional images are created with the horizontal axis as the antenna movement distance and the vertical axis as the time from transmission to reception of the electromagnetic wave, and the amplitude value of the reflected wave signal is below a predetermined amplitude value The white occupancy Rwi (i = 1 to 5), which is the ratio of the area of the waveform to the area of each cross-sectional image at each amplification degree Gi, is calculated, and among the five cross-sectional images, the calculated value Rwi is a predetermined reference. When the value is Rw0, Rwi <Rw If there is one cross-sectional image satisfying the relationship, the cross-sectional image is selected, the amplification factor Gi used to form the image is recorded as the optimum amplification factor, and there are a plurality of cross-sectional images satisfying the relationship Rwi <Rw0. In some cases, among the plurality of cross-sectional images, one cross-sectional image whose white occupancy ratio Rwi occupying the underground cross-sectional image is closest to the predetermined reference value Rw0 is selected and used to form the image. The amplification factor Gi is recorded as the optimum amplification factor, and when there is no underground cross-sectional image that satisfies the above relationship, the amplification factor Gi that is larger than the maximum value by a predetermined value Gx is recorded as the optimum amplification factor.
[0006]
[Problems to be solved by the invention]
In this prior art, there is no contrivance to change the amplification degree of the amplifier so as to increase with time after the electromagnetic wave is radiated to the soil until the reflected wave is received. Gi is kept constant in obtaining a cross-sectional image of one underground, so it cannot sufficiently cope with the change in attenuation of electromagnetic waves by soil in the depth direction, and the underground exploration of the underground object can be accurately performed. I can't do it.
[0007]
Another problem of the above-described prior art is using the occupation ratio Rwi occupied by the area of the white region in the underground sectional image obtained by using each amplification degree Gi, in other words, the two-dimensional image of the underground sectional image. There is a problem that computation is performed, computation processing is complicated, and time is required.
[0008]
The object of the present invention is to change the amplification factor of the high-frequency amplifier in the period from the radiation of the electromagnetic wave to the completion of the reception of the reflected wave so as to increase with the passage of time, resulting in a large amplitude due to the surface of the concealed place such as the ground In addition to preventing adverse effects caused by reflected waves, it is possible to automatically enable accurate exploration of buried objects regardless of various attenuation rates of electromagnetic waves in concealed places such as soil, and to simplify the calculation process. An object of the present invention is to provide an underground exploration method and apparatus capable of being buried.
[0009]
[Means for Solving the Problems]
  The present invention radiates electromagnetic waves to the concealment place while moving along the surface of the concealment place where the buried object is buried,
  Receives reflected waves from buried objects,
  In the buried object exploration method for exploring the buried object in the concealed place based on the time difference between the radiated electromagnetic wave and the received reflected wave,
  While moving by a predetermined first distance Δd, the received reflected wave is amplified and stored in a memory with a plurality of amplification / time patterns that change so that the amplification increases with time.
  This store operation to the memory is repeated over a predetermined second distance L1,
  Corresponding to the average value Pjz or the average value Pjz of the intensity of the reflected wave over the second distance L1 for each position in the depth direction from the surface of the concealment place to the predetermined depth DP1 near the surface for each pattern. Find the value
  For each pattern, the maximum value and the minimum value of the average value Pjz or the value corresponding to the average value Pjz are obtained,
  Among each pattern, a pattern in which N12j is the smallest to the extent that the maximum value and the minimum value are saturated within the amplification dynamic range is selected as an optimum pattern.
  Exploring buried objects using the reflected wave data amplified in this optimal pattern and stored in memoryAnd
  The degree of saturation N12j is a buried object search method characterized in that the maximum value and the minimum value are the sum of numbers N1j and N2j equal to the saturation value of the amplification dynamic range.
  The present invention is characterized in that, when there are a plurality of the patterns having the minimum saturation level N12j, the pattern having the maximum difference Pjz1 between the maximum value and the minimum value is selected as the optimum pattern. .
  In addition, according to the present invention, when there are a plurality of the patterns having the minimum saturation level N12j, for each pattern, each position in the depth direction from the surface of the concealment place to the predetermined depth DP2 where the embedded object exists is provided. The average value Qjz of the absolute value of the intensity of the reflected wave over the second distance L1 or a value corresponding to the average value Qjz is obtained,
  Evaluate the degree of approximation between the predetermined intensity distribution in the depth direction of the reflected wave and the average value Qjz or the value corresponding to the average value Qjz of the absolute value for each pattern;
  As a result of the evaluation, among the patterns, the best approximated pattern is selected as the optimal pattern,
  The buried object is searched for using the reflected wave data amplified in this optimal pattern and stored in the memory.
  Further, according to the present invention, the approximate evaluation is performed for each position in the depth direction between the predetermined intensity distribution and the average value Qjz of the absolute value for each pattern or a value corresponding to the average value Qjz. The sum of the squares of the differences or a value corresponding to the sum is obtained by calculation.
  Further, the present invention radiates electromagnetic waves to the concealment place while moving along the surface of the concealment place where the buried object is buried,
  Receives reflected waves from buried objects,
  In the buried object exploration method for exploring the buried object in the concealed place based on the time difference between the radiated electromagnetic wave and the received reflected wave,
  While moving by a predetermined first distance Δd, the received reflected wave is amplified and stored in a memory with a plurality of amplification / time patterns that change so that the amplification increases with time.
  This store operation to the memory is repeated over a predetermined second distance L1,
  Corresponding to the average value Pjz or the average value Pjz of the intensity of the reflected wave over the second distance L1 for each position in the depth direction from the surface of the concealment place to the predetermined depth DP1 near the surface for each pattern. Find the value
  For each of the patterns, the average value Pjz or the maximum value and the minimum value corresponding to the average value Pjz are obtained,
  Among each pattern, a pattern in which N12j is minimum to the extent that the maximum value and the minimum value are saturated within the amplification dynamic range is selected as an optimum pattern.
  Using the reflected wave data amplified in this optimal pattern and stored in memory, the buried object is explored,
  When there are a plurality of patterns having the minimum saturation degree N12j, a pattern having the largest difference Pjz1 between the maximum value and the minimum value is selected as an optimum pattern. It is.
  Further, the present invention radiates electromagnetic waves to the concealment place while moving along the surface of the concealment place where the buried object is buried,
  Receives reflected waves from buried objects,
  In the buried object exploration method for exploring the buried object in the concealed place based on the time difference between the radiated electromagnetic wave and the received reflected wave,
  While moving by a predetermined first distance d, the received reflected wave is amplified and stored in the memory with a plurality of amplification / time patterns that change so that the amplification increases with time. ,
  This store operation to the memory is repeated over a predetermined second distance L1,
  Corresponding to the average value Pjz or the average value Pjz of the intensity of the reflected wave over the second distance L1 for each position in the depth direction from the surface of the concealment place to the predetermined depth DP1 near the surface for each pattern. Find the value
  For each of the patterns, the average value Pjz or the maximum value and the minimum value corresponding to the average value Pjz are obtained,
  Among each pattern, a pattern in which N12j is minimum to the extent that the maximum value and the minimum value are saturated within the amplification dynamic range is selected as an optimum pattern.
  Using the reflected wave data amplified in this optimal pattern and stored in memory, the buried object is explored,
  When there are a plurality of the patterns having the minimum saturation degree N12j, the second distance for each position in the depth direction from the surface of the concealment place to the predetermined depth DP2 where the embedded object exists for each pattern. Find the average value Qjz of the absolute value of the intensity of the reflected wave over L1 or a value corresponding to the average value Qjz,
  Evaluating the degree of approximation between the predetermined intensity distribution in the depth direction of the reflected wave and the average value Qjz or the value corresponding to the average value Qjz of the absolute value for each pattern,
  As a result of the evaluation, a pattern with the best degree of approximation is selected as an optimum pattern among the patterns,
  This is a buried object exploration method characterized by exploring a buried object using the reflected wave data amplified in this optimum pattern and stored in a memory.
  Further, the present invention radiates electromagnetic waves to the concealment place while moving along the surface of the concealment place where the buried object is buried,
  Receives reflected waves from buried objects,
  In the buried object exploration method for exploring the buried object in the concealed place based on the time difference between the radiated electromagnetic wave and the received reflected wave,
  While moving by a predetermined first distance Δd, the received reflected wave is amplified and stored in a memory with a plurality of amplification / time patterns that change so that the amplification increases with time.
  This store operation to the memory is repeated over a predetermined second distance L1,
  For each pattern, the absolute value Qjz or the average value of the absolute values of the reflected wave over the second distance L1 for each position in the depth direction from the surface of the concealment place to the predetermined depth DP2 where the buried object exists. Find the value corresponding to Qjz,
  Evaluate the degree of approximation between the predetermined intensity distribution in the depth direction of the reflected wave and the average value Qjz or the value corresponding to the average value Qjz of the absolute value for each pattern;
  As a result of the evaluation, among the patterns, the best approximated pattern is selected as the optimal pattern,
  This is a buried object exploration method characterized by exploring a buried object using the reflected wave data amplified in this optimal pattern and stored in a memory.
  Further, according to the present invention, the approximate degree of evaluation is based on a predetermined intensity distribution in the depth direction of the reflected wave and each average value Qjz for each pattern or each value in the depth direction with a value corresponding to the average value Qjz. The sum of the squares of the differences for each position or a value corresponding to the sum is obtained.
  The present invention also includes means for radiating electromagnetic waves to a concealed place where a buried object is buried,
  An antenna for receiving the reflected wave from the buried object;
  Amplifying means for amplifying the output of the antenna with variable amplification;
  Means for detecting the moving distance of the antenna;
  A first memory for storing a plurality of different amplification degree / time patterns, the amplification degree of which changes so as to increase with the passage of time;
  A second memory for storing the output of the amplification means;
  In response to the output of the moving distance detecting means, while moving by a predetermined first distance Δd, the amplification degree of the amplifying means is changed and stored in the second memory in each of a plurality of patterns stored in the memory, Amplification degree control means for repeating this store operation over a predetermined second distance L1,
  The stored contents of the second memory are read, and for each pattern, the intensity of the reflected wave is measured over the second distance L1 for each position in the depth direction from the surface of the concealment place to a predetermined depth DP1 near the surface. A first calculating means for calculating an average value Pjz or a value corresponding to the average value Pjz;
  In response to the output of the first calculation means, second calculation means for calculating the maximum value and the minimum value of the average value Pjz or the value corresponding to the average value Pjz for each pattern;
  Selecting means for selecting, as an optimum pattern, a pattern having a minimum value N12j that is saturated within amplifying dynamic range of the amplifying means among the patterns in response to the output of the second calculating means; ,
  Means for exploring an embedded object using the reflected wave data stored in the second memory obtained by using the optimum pattern selected by the selection means.See
  The selection means is a buried exploration device characterized in that the degree of saturation N12j is determined as a sum of numbers N1j and N2j in which the maximum value and the minimum value are equal to a value at which the amplification dynamic range is saturated.
  Further, according to the present invention, when there are a plurality of the patterns having the minimum saturation degree N12j, the selection unit selects the pattern having the maximum difference Pjz1 between the maximum value and the minimum value as the optimum pattern. It is characterized by.
  Further, according to the present invention, when there are a plurality of the patterns having the minimum saturation level N12j, the selection means has a depth direction from the surface of the concealment place to the predetermined depth DP2 where the embedded object exists for each pattern. The average value Qjz of the absolute value of the intensity of the reflected wave or the value corresponding to the average value Qjz over the second distance L1 for each position of
  Evaluate the degree of approximation between the predetermined intensity distribution in the depth direction of the reflected wave and the average value Qjz or the value corresponding to the average value Qjz of the absolute value for each pattern;
  As a result of the evaluation, among the patterns, the best approximated pattern is selected as the optimal pattern,
  The buried object is searched for using the reflected wave data amplified in this optimal pattern and stored in the memory.
  The present invention also includes means for radiating electromagnetic waves to a concealed place where a buried object is buried,
  An antenna for receiving the reflected wave from the buried object;
  Amplifying means for amplifying the output of the antenna with variable amplification;
  Means for detecting the moving distance of the antenna;
  Multiple amplification levels / hours with different amplification levels that change with time A first memory for storing the inter-pattern,
  A second memory for storing the output of the amplification means;
  In response to the output of the moving distance detecting means, while moving by a predetermined first distance Δd, the amplification degree of the amplifying means is changed and stored in the second memory in each of a plurality of patterns stored in the memory, Amplification degree control means for repeating this store operation over a predetermined second distance L1,
  The stored contents of the second memory are read, and for each pattern, the intensity of the reflected wave is measured over the second distance L1 for each position in the depth direction from the surface of the concealment place to a predetermined depth DP1 near the surface. A first calculating means for calculating an average value Pjz or a value corresponding to the average value Pjz;
  In response to the output of the first calculation means, second calculation means for calculating the maximum value and the minimum value of the average value Pjz or the value corresponding to the average value Pjz for each pattern;
  Selecting means for selecting, as an optimum pattern, a pattern having a minimum value N12j that is saturated within amplifying dynamic range of the amplifying means among the patterns in response to the output of the second calculating means; ,
  Means for exploring an embedded object using reflected wave data stored in the second memory obtained using the optimum pattern selected by the selection means,
  The selecting means selects a pattern having a maximum difference Pjz1 between the maximum value and the minimum value as an optimal pattern when there are a plurality of the patterns having the minimum saturation level N12j. This is an object exploration device.
  The present invention also includes means for radiating electromagnetic waves to a concealed place where a buried object is buried,
  An antenna for receiving the reflected wave from the buried object;
  Amplifying means for amplifying the output of the antenna with variable amplification;
  Means for detecting the moving distance of the antenna;
  A first memory for storing a plurality of different amplification degree / time patterns, the amplification degree of which changes so as to increase with the passage of time;
  A second memory for storing the output of the amplification means;
  In response to the output of the moving distance detecting means, while moving by a predetermined first distance Δd, the amplification degree of the amplifying means is changed and stored in the second memory in each of a plurality of patterns stored in the memory, Amplification degree control means for repeating this store operation over a predetermined second distance L1,
  The stored contents of the second memory are read, and for each pattern, the intensity of the reflected wave is measured over the second distance L1 for each position in the depth direction from the surface of the concealment place to a predetermined depth DP1 near the surface. A first calculating means for calculating an average value Pjz or a value corresponding to the average value Pjz;
  In response to the output of the first calculation means, second calculation means for calculating the maximum value and the minimum value of the average value Pjz or the value corresponding to the average value Pjz for each pattern;
  Selecting means for selecting, as an optimum pattern, a pattern having a minimum value N12j that is saturated within amplifying dynamic range of the amplifying means among the patterns in response to the output of the second calculating means; ,
  Means for exploring an embedded object using reflected wave data stored in the second memory obtained using the optimum pattern selected by the selection means,
  When there are a plurality of the patterns having the minimum saturation level N12j, the selection means is provided for each position in the depth direction from the surface of the concealment place to the predetermined depth DP2 where the embedded object exists for each pattern. An average value Qjz of absolute values of reflected wave intensity over the second distance L1 or a value corresponding to the average value Qjz is obtained,
  Evaluating the degree of approximation between the predetermined intensity distribution in the depth direction of the reflected wave and the average value Qjz or the value corresponding to the average value Qjz of the absolute value for each pattern,
  As a result of the evaluation, a pattern with the best degree of approximation is selected as an optimum pattern among the patterns,
  This is a buried object exploration apparatus characterized by exploring a buried object using the reflected wave data amplified in this optimum pattern and stored in a memory.
  Further, according to the present invention, the selection means may calculate a difference of 2 for each position in the depth direction between the predetermined intensity distribution and the average value Qjz of the absolute value for each pattern or a value corresponding to the average value Qjz. It is characterized by evaluating a degree of approximation by calculating a sum of powers or a value corresponding to the sum.
  The present invention also includes means for radiating electromagnetic waves to a concealed place where a buried object is buried,
  An antenna for receiving the reflected wave from the buried object;
  Amplifying means for amplifying the output of the antenna with variable amplification;
  Means for detecting the moving distance of the antenna;
  A first memory that stores a plurality of mutually different amplification degrees and time patterns in which the amplification degree changes so as to increase with the passage of time;
  A second memory for storing the output of the amplification means;
  A third memory for storing a predetermined intensity distribution in the depth direction of the reflected wave;
  In response to the output of the movement distance detection means, while moving by a predetermined first distance Δd, the amplification degree of the amplification means is changed and stored in the second memory in each of a plurality of patterns stored in the memory, Amplification degree control means for repeating this store operation over a predetermined second distance L1,
  The stored contents of the second memory are read out, and for each pattern, the second distance L1 for each position in the depth direction from the surface of the concealment place to at least a predetermined depth DP2 in the vicinity where the embedded object is embedded. First arithmetic means for calculating and storing the average value Qjz of the absolute value of the intensity of the reflected wave over the average value Qjz or the value corresponding to the average value Qjz;
  Based on the predetermined intensity distribution stored in the third memory and the stored content read from the fourth memory, the predetermined intensity distribution and the average value Qjz or the average value Qjz of the absolute values for each pattern An evaluation means for evaluating the degree of approximation with the value corresponding to
  In response to the output of the evaluation means, a selection means for selecting, as an optimal pattern, a pattern that has the best approximation among the patterns,
  And a means for exploring the buried object using the reflected wave data stored in the second memory obtained by using the optimum pattern selected by the selecting means. is there.
  In the invention, it is preferable that the evaluation unit calculates a difference of 2 for each position in the depth direction between the predetermined intensity distribution and the average value Qjz of the absolute value for each pattern or a value corresponding to the average value Qjz. It is characterized by calculating a sum of powers or a value corresponding to the sum.
[0010]
According to the present invention, a plurality of amplification factors / time patterns are stored in the first memory, and the amplification factor of the high-frequency amplifier increases with the passage of time in the reflected waves received at each amplification factor / time pattern. The store operation of the reflected wave to the second memory using each of the plurality of amplification / time patterns is performed while moving by a predetermined first distance Δd (for example, 2 cm). Such an operation is repeated over a predetermined second distance L1 (for example, 5 m). The average value of the intensity of the reflected wave over the second distance L1 for each position in the depth direction from the surface of the concealment place to a predetermined depth DP1 (for example, 50 cm) in the vicinity of the surface for each of a plurality of amplification / time patterns Find Pjz or its corresponding value.
In the range from the surface of the concealment place to the depth DP1, the amplitude of the reflected wave from the surface of the concealment place such as the ground surface is large, and therefore there is a high possibility that the high-frequency amplifier that amplifies the reflected wave from the receiving antenna will be saturated. Therefore, according to the present invention, the maximum value and the minimum value of the average value Pjz or the value corresponding to the average value Pjz are obtained for each amplification degree / time pattern, and the maximum value and the minimum value are determined as the amplification dynamic range of the amplifier. Among them, the amplification factor / time pattern having the minimum saturation level N12j is selected as the optimum pattern, and the buried object is searched using the optimum amplification factor / time pattern thus selected.
The saturation degree N12j may be a sum of numbers N1j and N2j in which the maximum value and the minimum value are equal to the saturation value of the amplification dynamic range. When there are a plurality of the patterns having the minimum saturation level N12j, a pattern having the maximum difference Pjz1 between the maximum value and the minimum value is selected as the optimum pattern from the plurality of patterns, thereby amplifying dynamic The amplification degree can be increased by using the entire range as much as possible.
When there are a plurality of the patterns having the minimum saturation level N12j, every position in the depth direction from the surface of the concealment place to at least a predetermined depth DP2 (for example, 1 m or 2 m) in the vicinity where the embedded object is embedded The average value Qjz of the absolute value of the reflected wave over the second distance L1 or the value corresponding thereto is calculated to obtain a predetermined intensity distribution in the depth direction of the reflected wave and the absolute value of each pattern. The degree of approximation with the average value Qjz or the value corresponding to the average value Qjz is evaluated, and as a result of the evaluation, the best pattern of the degree of approximation is selected as the optimum pattern among the patterns. The buried object is searched using the reflected wave data amplified and stored in the memory. In evaluating the degree of approximation, a least square method may be used.
The operation of amplifying the reflected wave with a plurality of amplification degree / time patterns and storing it in the second memory repeatedly repeats the amplification and storage operations in each pattern every time a predetermined distance is displaced within the first distance Δd. Alternatively, the amplification and the store operation using a plurality of amplification degree / time patterns may be repeated at the same position of the concealment place, and during the movement of the first distance Δd, the surface of the buried object is moved to the position. Regardless, the amplification and store operations may be performed with the plurality of amplification / time patterns described above.
Thus, according to the present invention, it is possible to automatically find the optimum amplification factor / time pattern in one scan of the reception operation of the reflected wave due to the radiation of the electromagnetic wave on the surface of the concealment place. Therefore, even if the exploration site is a road with a large amount of traffic, the exploration work can be completed in a short time, so that traffic is not hindered and worker safety is ensured. In addition, the intensity distribution of the reflected wave is obtained by calculating the average value Pjz in the scanning direction or a value corresponding thereto, and a one-dimensional distribution in the depth direction is obtained to make a determination for finding the optimum amplification degree / time pattern. The determination operation can be simplified, and the arithmetic processing can be performed in a short time.
Further, according to the present invention, the stored contents of the reflected wave for each of the plurality of amplification degree / time patterns stored in the second memory are read out, and at least in the vicinity of the vicinity where the embedded object is embedded from the surface of the concealment place. The average value Qjz or the value corresponding to the absolute value of the intensity of the reflected wave is calculated and stored in the fourth memory over the second distance L1 for each position in the depth direction up to a predetermined depth DP2 (for example, 1 m or 2 m). . In the third memory, a predetermined intensity distribution that is a reference in the depth direction of the reflected wave is stored.
The evaluation means evaluates the degree of approximation of each of a plurality of amplification factors / time patterns based on the intensity distribution stored in the third memory and the stored content read from the fourth memory, The amplification degree / time pattern with the best approximation is selected as the optimum pattern. Using the selected amplification degree / time pattern, the buried object is searched. As an evaluation method by the evaluation means, for example, a least square method or the like can be used. Thus, the calculation of finding the optimum amplification factor / time pattern can be simplified by making the intensity distribution of the reflected wave one-dimensional distribution in the depth direction.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing a simplified overall configuration of an underground exploration device according to an embodiment of the present invention. In the soil 5, a pipe 6 that is an embedded object such as a steel pipe that transports a fluid such as gas is embedded. On the ground, in order to search for the tube 6, a pulse of 8 MHz, for example, 100 MHz to 1000 MHz shown in FIG. The electromagnetic wave radiated from the transmitting antenna 7 travels as shown by an arrow 10 and is reflected by the tube 6, and the reflected wave travels as shown by a reference sign 11 and is received by another receiving antenna 12. The output shown in FIG. 2 (2) is obtained from the receiving antenna 12. The time difference ΔT from when the electromagnetic wave is radiated from the transmitting antenna 7 to when the reflected wave is received by the receiving antenna 12 is the distance in the depth direction between the surface of the soil 5 and the pipe 6, that is, the depth and the kind of soil, and therefore the soil It corresponds to the attenuation factor.
[0012]
By vertically fixing the transmitting antenna 7 and the receiving antenna 12 and moving across the underground pipe 6 as indicated by the arrow 13 in FIG. An original image of a cross section in the plane can be obtained. The distance traveled by these

antennas

7 and 12 is detected by a distance sensor 14. The distance sensor generates one pulse every time it moves 2 cm in the x direction, which is the moving direction 13, and calculates the scanning distance by counting this pulse by the processing circuit 15 realized by a microcomputer or the like. Can be sought.
[0013]
The synchronization signal generation circuit 16 generates a clock signal of, for example, 500 kHz, and the pulser 8 gives a pulse of, for example, 50 kHz to the transmission antenna 7, so that the time interval W1 of each pulse is 20 μsec. In the receiving circuit 17 connected to the receiving antenna 12, the output of the receiving antenna 12 is given to the amplifying means U1. The amplifying means U1 comprises an attenuator ATT1 and a high-frequency amplifier AMP1 connected in cascade thereafter.
[0014]
As shown in FIG. 3, the amplification degree between the input and output of the amplifying unit U1 changes so as to increase with time in the depth direction of the soil 5, and thus with time, for example, from -5 dB to +35 dB. Is done. The amplification degree of the amplifier AMP1 is kept at a predetermined value, that is, 40 dB in this embodiment. The attenuation factor of the attenuator ATT1 is changed from −45 dB to −5 dB so as to decrease with time. Accordingly, as described above, the unit U1 can obtain the amplification characteristic shown in FIG. Thus, each amplifier AMP1 has a dynamic range of about 40 dB with a good S / N ratio. As a result, it becomes possible for the first time that the weak reflected wave of the pipe 6 embedded in the soil 5 is amplified with a large amplification degree and led to the line 18.
[0015]
In order to achieve the characteristic that the attenuator ATT1 changes so that the attenuation rate corresponding to the amplification degree shown in FIG. 3 decreases with time, the read-only memory M1 is provided. The contents are read in response to a read pulse from the counter 19, converted into an analog signal by the digital / analog converter DA1, and supplied to the attenuator ATT1. As described above, the attenuator ATT1 is realized by, for example, a field effect transistor. When the voltage corresponding to the attenuation rate is given to the gate of the attenuator ATT1 as it changes over time, or when it is realized by a bipolar transistor, its base is used. Is supplied with a voltage corresponding to the attenuation rate.
[0016]
For example, a pulse of 500 kHz synchronized with the signal applied to the pulser 8 from the synchronization signal generation circuit 16 is applied to the counter 19 as shown in FIG.
[0017]
The sampler 21 is given a signal from the receiving circuit 17 via the line 18 from the amplifier AMP1 of the amplifying means U1 via the line 18, and is sampled by the sampling pulse shown in FIG. This sampling pulse is supplied from the synchronization signal generation circuit 16 via the line 22.
[0018]
The time course of the amplification degree of the amplifying means U1 is as shown in FIG. 2 (5), and the waveform derived from this to the line 18 from the amplifier AMP1 of the amplifying means U1 is shown in FIG. 2 (2). Of the reception output of the receiving antenna 12, the amplitude of the waveform at the initial reception is suppressed and attenuated with a large attenuation rate, and the amplitude of reflection at a large depth is amplified with a large amplification degree as shown in FIG.
[0019]
The output of the sampler 21 is filtered by the filter 25, converted to a digital signal by the analog / digital converter 26, and supplied to the processing circuit 15. The output of the synchronizing signal generating circuit 16 is given to the low frequency synchronizing signal generating circuit 27, the synchronizing operation of the counter 19 is performed, and reset at every electromagnetic wave radiation time W1 by the transmitting antenna 7, and the output from the line 28 is low. The frequency synchronization signal 1 kHz is given to the processing circuit 15. In this way, the processing circuit 15 can accurately obtain an image of the vertical section of the soil 5 including the depth of the underground buried pipe 6 by the reflected wave signal sampled by the sampler 21.
[0020]
Amplifying means U1 comprising a combination of attenuator ATT1 and amplifier AMP1 maintains a good S / N ratio due to thermal noise of amplifier AMP1 and attenuates a reflected wave having a large amplitude due to the ground surface with a large attenuation factor. In addition, a weak reflected wave from the underground pipe 6 can be amplified with a large amplification degree.
[0021]
A cross-sectional image of the soil 5 received by the receiving circuit 17 and sampled by the sampler 21 and obtained through the filter 25 and the analog-digital converter 26 is stored in the memory M2, and this image is shown in FIG. Reference numeral 31 indicates the surface of the soil 5, and the image 32 represents the vicinity of the top of the underground pipe 6. 4 corresponds to the x direction which is the scanning direction 13, and the vertical direction in FIG. 4 corresponds to the z direction which is the depth direction from the ground surface 31 of the soil 5.
[0022]
FIG. 5 shows the received intensity of the reflected wave in the depth direction at each scanning position in the x direction of the image shown in FIG. As shown in FIG. 5A, the amplitude, that is, the intensity of the reflected wave is represented by a total of 256 gradations in the range of the minimum value A that is 0 gradation and the maximum value B that is 255 gradations. The reflected wave maximum value 33 is saturated at the gradation maximum value B, that is, the amplifier AMP1 is saturated. The waveform 34 of the reflected wave is saturated at the minimum gradation value A, that is, the amplifier AMP1 is saturated. The intensity in the depth direction of the reflected wave shown in FIG. 5 (1) saturates the amplifier AMP1, and the amplification degree / time pattern in the amplification means U1 is determined as inappropriate as described later. .
[0023]
The intensities in the depth direction at other scanning positions of the image stored in the memory M2 are shown in FIG. The maximum value 35 and the minimum value 36 of the intensity are in the vicinity of the maximum value B and the minimum value A, and are within the range of predetermined values B1, B2, A1, and A2. Therefore, the amplification function of the amplifier AMP1 Therefore, a minute reflected wave from the tube 6 can be amplified with a large amplification degree. The amplification degree / time pattern when such a reflected wave intensity distribution of FIG. 5B is obtained is selected as described below as an optimum one.
[0024]
FIG. 6 is a flowchart for explaining the operation of the processing circuit 16. In response to the output of the distance sensor 14, while moving in the x direction 13 by a predetermined first distance Δd (for example, 2 cm), a plurality of n (for example, 5) amplification degree / time patterns stored in the memory M1 are used. The image shown in FIG. 4 by changing the amplification degree of the amplifying means U1 is repeated over the second distance L1 (for example, 5 m) in the x direction 13 so that the image shown in FIG. Stored in the memory M2.
[0025]
This operation is achieved by executing steps a1 to a8 in FIG. Moving from step a1 to step a2, one STC1 is selected from the total n (5 in this embodiment) amplification factor / time pattern STCi (i = 1 to n) stored in the memory M1, In a3, an image using the amplification degree / time pattern STC1 is obtained as indicated by reference numeral F (1, 1) in FIG. In step a4, i is incremented. If i> n is not satisfied in step a5, the process proceeds to step a3 again, and the depth direction of the reflected wave shown in FIG. 7 (2) using the next amplification factor / time pattern STC2 A distribution F (2, 1) of is obtained. Similarly, as shown in FIGS. 7 (3) to 7 (5), while moving by the first distance Δd in the x direction 13 using the amplification factor / time patterns STC3, STC4 and STC5, the depth of the reflected wave is increased. Distributions F (3, 1), F (4, 1), F (5, 1) in the vertical direction are obtained.
[0026]
When the distance sensor 14 detects that the transmitting and receiving

antennas

7 and 12 have moved by a distance Δd in step a6, the process proceeds to the next step a7, where it is determined whether or not the

antenna

7 and 12 has moved by a predetermined distance L1. Returning to step a2 again, the same operation is repeated, and at the next position in the x direction 13, the reflected wave intensity distributions F (1,2), F (2,2), F (3,2), F (4 , 2), F (5, 2) are obtained in the same manner. Thereafter, the same operation is repeated. here,
L1 = m · Δd (1)
In one embodiment of the present invention, L1 = 5 m as described above, Δd = 2 cm, and therefore m = 250. Thus, the intensity distributions F (1,1) to F (5,250) of the reflected waves in the depth direction at the respective positions in the x direction 13 shown in FIG. 7 are stored in the memory M2.
[0027]
FIG. 8 is a flowchart for explaining the operation subsequent to FIG. 6 in the processing circuit 15. In FIG. 8, for each of a plurality of n amplification factors / time patterns, from the ground surface 31 to a predetermined depth DP1 (for example, 50 cm) in the vicinity of the ground surface 31, for each position in the depth direction, that is, in the z direction. The average value Pjz of the intensity of the reflected wave is calculated over the second distance L1. This operation is achieved in steps b1 to b7 in FIG. 8, and for each amplification degree / time pattern, the maximum value Pjzmax of the average value Pjz and the number in the z direction are obtained, and the minimum value Pjzmin and z Find the number of directions. The calculation regarding the maximum value and the minimum value for each of the plurality of amplification / time patterns is achieved by executing steps b8 and b9.
[0028]
Moving from step b1 in FIG. 8 to step b2, among the plurality of n amplification factor / time patterns STC1 to STCn, first, j = 1, and in the next step b3, n data corresponding to the amplification factor / time pattern STC1 are used. The intensity distributions F (1,1) to F (1,250) in a certain depth direction are read from the memory M2 from the ground surface to the depth DP1. In the next step b4, the position in the z direction which is the depth direction is set as z = 1, and in the next step b5, the average value Pjz is calculated and obtained.
[0029]
[Expression 1]

[0030]
In the above Equation 2, g (x, z) represents each waveform of each of the intensity distributions F (1,1) to F (1,250).
[0031]
After obtaining the average value Pjz by the expression 2 in step b5, z is incremented by 1 in the next step b6 to set the next position in the depth direction, and the depth DP1 is not exceeded in step b7 (ie, If it is determined that z> DP1 does not hold, the process proceeds to step b5 again, and the same operation is repeated, thus calculating the average value Pjz for each position in the depth direction.
[0032]
Therefore, in step b8, the maximum value Pjzmax for each average value Pjz and the number in the z direction that is the depth direction are obtained. In step b9, the minimum value Pjzmin of each average value Pjz is obtained, and the minimum value Pjzmin obtains the number in the depth direction. Thus, in the next step b10, j is incremented by 1. If j> n is not satisfied, the process returns to step b3. Thus, the maximum value and the number of average values Pjz for all the multiple n amplification factor / time patterns STC1 to STC5 are returned. And the minimum value and the number thereof are obtained. In this way, Table 1 is obtained and stored in the memory M2a.
[0033]
[Table 1]

[0034]
Next, the processing circuit 15 performs the operation shown in FIG. In FIG. 9, the contents of Table 1 stored in the memory M2a are read out, and the maximum value and the minimum value among the plurality of n amplification degree / time patterns STC1 to STC5 are the amplification dynamic range of the amplification means U1, For example, it is determined whether or not it exists within a wide range within the amplification dynamic range within 40 dB, and thereby, one of the optimum amplification degree and time patterns is selected, which is the depth of FIG. This corresponds to the intensity distribution of the reflected wave in the vertical direction.
[0035]
Shifting from step c1 to step c2 in FIG. 9, one of a plurality of n amplification factor / time patterns STC1 to STC5 is set as j = 1. In step c3, the number N1j with the maximum value Pjzmax in Table 1 having the maximum gradation 255 is counted, and the number N2j with the minimum value Pjzmin having the minimum gradation and the intensity zero is counted. there
N1j + N2j = N12j (3)
Is calculated. This added value N12j represents the degree of amplification of the amplifier.
[0036]
In step c4, a difference Pjz1 between the maximum value Pjzmax and the minimum value Pjzmin is calculated and obtained.
[0037]
Pjzmax−Pjzmin = Pjz1 (4)
In step c5, j is incremented by 1, and the next amplification factor / time pattern STCj is set. Such an operation is repeated until j> n in step c6, and all the amplification factors / time patterns of the plurality n are repeated. Repeat for STC1-STCn.
[0038]
In step c7, the pattern STCj having the minimum sum N12j obtained by the calculation in equation 3 in step c3 is selected. In step c8, if the selected pattern STCj is single, the pattern STCj is selected. The selected pattern STCj is selected as the optimum pattern. When there are a plurality of patterns STCj having the minimum sum N12j in step c8, the process proceeds to step c9, and the difference obtained from the selected plurality of patterns STCj based on Equation 4 in step c4 described above. The pattern STCj having the maximum Pjz1 is selected as the optimum pattern.
[0039]
Using the cross-sectional image of the soil 5 using the optimum amplification degree / time pattern STCj thus obtained, the underground circuit 6 is searched in the processing circuit 15. Note that the underground pipe 6 in the soil 5 has a relatively small shape, and therefore does not adversely affect the average value Pjz.
[0040]
In another embodiment of the present invention, a value corresponding to the average value Pjz may be obtained instead of the average value Pjz.
[0041]
Another embodiment of the present invention will be described with reference to FIGS. FIG. 10 is a cross-sectional image of the soil 5 stored in the memory M2 obtained by the above-described FIG. In the embodiment of the present invention, a predetermined intensity distribution in the depth direction of the reflected wave is stored in the memory M3 as shown in FIG. This reference intensity distribution is an absolute value of the intensity of the reflected wave, has a characteristic corresponding to the attenuation rate of the electromagnetic wave of the soil 5, and is determined in advance by experiments. As shown in FIG. 5 described above, the intensity of the reflected wave at each position in the scanning direction 13 is shown in FIG. 12 (1), and the absolute value thereof is a so-called full-wave rectified waveform. It is obtained as shown in (2). The degree of approximation of the average value Qjz of the absolute values obtained in FIG. 12 (2) approximated to the reference intensity distribution shown in FIG. 11 is evaluated, and the amplification / time pattern having the highest degree of approximation is evaluated. Is selected as the optimum pattern. Such an operation is illustrated in the flowchart achieved by the processing circuit 15 shown in FIGS. Referring to FIG. 13, the process proceeds from step d1 to step d2. In this step d2, the operation shown in FIG. 6 is achieved, and the memory M2 has a plurality of n amplification factors as shown in FIG. For each of the time patterns STC1 to STCn, the intensity distributions F (1,1) to F (5,250) in which the amplification degree of the amplifying unit U1 is changed while moving by the first distance Δd are stored.
[0042]
In step d3, j = 1 is set in order to set one of a plurality of n amplification factor / time patterns STC1 to STCn, and an intensity distribution that is data corresponding to the set pattern STCj, for example, j = 1, F (1,1) to F (1,250) are read from the ground surface 31 to the depth DP2. This depth DP2 may be DP2 = DP1, and may be a predetermined value such as 1 m or 2 m, for example.
[0043]
In step d5, the absolute value of the intensity of the reflected wave is obtained as shown in FIG. 12 (2) based on the intensity distribution in the depth direction shown in FIG. 12 (1), and this absolute value is obtained in the x direction. It is expressed by f (x, z) corresponding to the position of 13 and the position in the z direction which is the depth direction.
[0044]
In step d6, the position in the depth direction is set as z = 1, and the average value Qjz of the absolute values f (x, z) of the intensity of the reflected wave is obtained.
[0045]
[Expression 2]

[0046]
In step d8, z is incremented by 1 to set the next position in the depth direction. When the depth DP2 is not exceeded in step d9 (when z> DP2 is not satisfied), the process returns to step d7 and the calculation is repeated. Thus, for each position in the depth direction, the average value Qjz of the absolute value f (x, z) of the intensity of the reflected wave is calculated over the second distance L1, and the calculated result is stored in the memory M4. Store.
[0047]
In step d10, a value ΔFj is calculated in order to evaluate the approximate degree of the average value Qjz and the reference intensity distribution fp (z) shown in FIG. 11 stored in the memory M3.
[0048]
[Equation 3]

[0049]
In step d11, j is incremented by 1, another amplification factor / time pattern is set, and when j does not exceed n (ie, when j> n is not satisfied), the process returns to step d1. In this way, the above-described operation is repeated for each of a plurality of n amplification factor / time patterns STC1 to STCn to obtain the deviation ΔFj. This deviation ΔFj is the sum of the squares of the difference between the average value Qjz for each position in the depth direction and the reference intensity distribution fp (z), and is a value obtained by the method of the least square method.
[0050]
The deviation ΔFj obtained in this way is calculated by the operation of FIG. 14, and an optimum amplification degree / time pattern is selected. The process proceeds from step e1 to step e2 in FIG. 14, and a minimum value is selected from among the deviations ΔF1 to ΔFn for each of the plurality of n amplification factor / time patterns STC1 to STCn. Therefore, in step e3, the amplification degree / time pattern STCj from which the deviation ΔFj, which is the minimum value, is obtained is selected as the optimum one.
[0051]
Also in the embodiment of the present invention, the pipe 6 embedded in the soil 5 has a relatively short length along the x-direction 13 in which the soil 5 is scanned, and therefore, the average value Qjz is not adversely affected. Absent. In the above-described embodiment, although the evaluation to the extent that the average value Qjz and the reference intensity distribution fp (z) are approximated is performed according to Equation 6 using the least square method, in other embodiments of the present invention, Alternatively, the evaluation may be performed to the extent approximated by other methods.
[0052]
Instead of the operation in step c9 in FIG. 9 described above, the operations in FIGS. 13 and 14 may be performed. That is, in step c8 of FIG. 9, when there are a plurality of patterns STCj having the minimum sum N12j, steps d3 to d13 of FIG. 13 are executed, and thereafter steps e1 to e4 of FIG. 14 are executed. May be.
[0053]
As still another embodiment of the present invention, instead of the average value Qjz, a value corresponding to the average value Qjz may be calculated and obtained.
[0054]
The present invention can be implemented not only for exploring buried objects in soil, but also for a wide range such as for exploring buried objects in buildings and underwater.
[0055]
Further, the transmission antenna 7 and the reception antenna 12 may be combined.
[0056]
【The invention's effect】
According to the present invention, a plurality of mutually different amplification factors that change so that the amplification factor increases with the lapse of time from the radiation of the electromagnetic wave to the concealed place where the buried object is buried until the reception of the electromagnetic wave is completed. Store the output of the amplification means for each amplification degree / time pattern while moving by a predetermined first distance ΔD in response to the recording from the means for detecting the moving distance of the antenna using the time pattern, This operation is repeated over the second distance L1, and the second distance L1 for each position in the depth direction from the surface of the concealment place to the predetermined depth DP1 in the vicinity of the surface for each of the plurality of amplification factor / time patterns. The average value Pjz of the electromagnetic wave intensity or the value corresponding to this is calculated, and the maximum value and the minimum value for each pattern are saturated within the amplification dynamic range of the amplification means. The amplification degree / time pattern with the smallest N12j is selected as the optimum pattern, thereby preventing the saturation of the amplification means and sufficiently achieving the amplification function of the amplification means to generate a weak reflected wave by the embedded object. It enables amplification with the degree of amplification.
[0057]
Moreover, according to the present invention, it is possible to find the optimum amplification degree / time pattern by one scan of the concealment place, and the workability is good, and therefore, troubles are caused on the road where the traffic is heavy. And the operator is safe.
[0058]
Furthermore, according to the present invention, the optimum amplification degree can be obtained by obtaining an average value Pjz in the scanning direction along the surface of the concealment place for the intensity distribution of the reflected wave, which is the output of the amplification means, and obtaining a one-dimensional distribution in the depth direction. -The time pattern can be easily selected, thereby simplifying the arithmetic processing and shortening the arithmetic processing time.
[0059]
According to the present invention, the output of the reflected wave obtained by the amplifying means is second for each position in the depth direction from the surface of the concealment place to at least a predetermined depth DP2 in the vicinity where the embedded object is embedded. The average value Qjz of the absolute value of the intensity of the reflected wave over the distance L1 or a value corresponding thereto is calculated, and the average value Qjz thus obtained or a value corresponding thereto is preliminarily used as a reference in the depth direction of the reflected wave. The degree of approximation with the determined intensity distribution is evaluated, and the degree of approximation is the best, that is, the amplification / time pattern with the highest degree of approximation is selected as the optimum pattern, so the same effect as described above is achieved. It is possible to simplify the arithmetic processing by a simple operation and achieve a highly accurate exploration of the buried object.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically showing an overall configuration of an embodiment of the present invention.
FIG. 2 is a waveform diagram for explaining the operation of the embodiment shown in FIG. 1;
3 is a graph showing characteristics of amplifying means U1 in receiving circuit 17 in the embodiment of FIG.
FIG. 4 is a diagram showing a cross-sectional image of soil 5;
FIG. 5 is a diagram showing the intensity distribution of reflected waves in the depth direction at a certain position in the x direction 13 where the ground surface 31 of the soil 5 is scanned.
FIG. 6 shows the amplification degree of the amplification means U1 by a plurality of n amplification degree / time patterns STC1 to STCn stored in the memory M1 while moving by scanning in the x direction by a predetermined first distance Δd. It is a flow chart for explaining the operation which changes and stores in the 2nd memory M2, and repeats this store operation over the 2nd predetermined distance L1.
FIG. 7 is a diagram showing intensity distributions F (1, 1) to (5 to 250) in the depth direction for each of a plurality of n amplification factors and time patterns.
FIG. 8 shows the reflected wave over a second distance L1 for each position in the depth direction from the ground surface 31 of the soil 5 to a predetermined depth DP1 in the vicinity of the ground surface for each of a plurality of n amplification degree / time patterns. It is a flowchart for demonstrating the operation | movement which calculates | requires the average value Pjz of intensity | strength, and also calculates | requires the maximum value and minimum value.
9 shows a pattern in which the above-mentioned maximum value and minimum value are within the amplification dynamic range of the amplifying means U1 among the plurality of n amplification degree / time patterns STC1 to STCn, and the pattern covers almost the entire amplification dynamic range. It is a flowchart for demonstrating the operation | movement for selecting as an optimal pattern.
FIG. 10 is a diagram showing a cross-sectional image of soil 5 stored in a memory M2 according to another embodiment of the present invention.
FIG. 11 is a diagram showing an intensity distribution serving as a predetermined reference in the depth direction of the reflected wave stored in the memory M3.
FIG. 12 is a diagram for explaining an absolute value of intensity of a reflected wave.
FIG. 13 is a diagram illustrating a processing circuit 15 that calculates a deviation ΔFj between a predetermined intensity distribution fp stored in the memory M3 and an average absolute value Qjz for each of a plurality of n amplification factor / time patterns STC1 to STCn. FIG.
FIG. 14 is a flowchart for explaining an operation of selecting, as an optimum pattern, amplification factor / time patterns STC1 to STCn that are best approximated by the processing circuit 15 based on the deviation ΔFj.
[Explanation of symbols]
5 soil
6 pipes
7 Transmitting antenna
8 Pulsa
9 High voltage power supply
12 Receiving antenna
14 Distance sensor
15 Processing circuit
17 Receiver circuit
18,22 lines
19 Counter
21 Sampler
ATT1 attenuator
AMP1 high frequency amplifier
DA1 Digital / analog converter
U1 amplification means

Claims

While moving along the surface of the concealed place where the buried object is buried, radiate electromagnetic waves to the concealed place,
Receives reflected waves from buried objects,
In the buried object exploration method for exploring the buried object in the concealed place based on the time difference between the radiated electromagnetic wave and the received reflected wave,
While moving by a predetermined first distance Δd, the received reflected wave is amplified and stored in a memory with a plurality of amplification / time patterns that change so that the amplification increases with time.
This store operation to the memory is repeated over a predetermined second distance L1,
Corresponding to the average value Pjz or the average value Pjz of the intensity of the reflected wave over the second distance L1 for each position in the depth direction from the surface of the concealment place to the predetermined depth DP1 near the surface for each pattern. Find the value
For each pattern, the maximum value and the minimum value of the average value Pjz or the value corresponding to the average value Pjz are obtained,
Among each pattern, a pattern in which N12j is the smallest to the extent that the maximum value and the minimum value are saturated within the amplification dynamic range is selected as an optimum pattern.
Using the reflected wave data amplified in this optimal pattern and stored in the memory, the buried object is explored ,
The degree of saturation N12j is the sum of numbers N1j and N2j in which the maximum value and the minimum value are equal to the saturation value of the amplification dynamic range.

When the pattern having a degree N12j to minimize saturation there is a plurality, a pattern the difference between the maximum value and the minimum value Pjz1 is maximum, according to claim 1 Symbol placement and selects as the optimum pattern Exploration method for buried objects.

When there are a plurality of the patterns having the minimum saturation degree N12j, the second distance for each position in the depth direction from the surface of the concealment place to the predetermined depth DP2 where the embedded object exists for each pattern. The average value Qjz of the absolute value of the intensity of the reflected wave over L1 or a value corresponding to the average value Qjz is obtained,
Evaluate the degree of approximation between the predetermined intensity distribution in the depth direction of the reflected wave and the average value Qjz or the value corresponding to the average value Qjz of the absolute value for each pattern;
As a result of the evaluation, among the patterns, the best approximated pattern is selected as the optimal pattern,
Exploration process according to claim 1 Symbol placement of buried objects characterized by probing the buried object by using the data of the reflected wave which is stored in the memory are amplified by the optimum pattern.

The approximate degree of evaluation is the square of the difference between each position in the depth direction between the predetermined intensity distribution and the average value Qjz of the absolute value for each pattern or a value corresponding to the average value Qjz. 4. The method for exploring buried objects according to claim 3, wherein the sum or a value corresponding to the sum is calculated.

While moving along the surface of the concealed place where the buried object is buried, radiate electromagnetic waves to the concealed place,
Receives reflected waves from buried objects,
In the buried object exploration method for exploring the buried object in the concealed place based on the time difference between the radiated electromagnetic wave and the received reflected wave,
While moving by a predetermined first distance Δd, the received reflected wave is amplified and stored in a memory with a plurality of amplification / time patterns that change so that the amplification increases with time.
This store operation to the memory is repeated over a predetermined second distance L1,
Corresponding to the average value Pjz or the average value Pjz of the intensity of the reflected wave over the second distance L1 for each position in the depth direction from the surface of the concealment place to the predetermined depth DP1 near the surface for each pattern. Find the value
For each pattern, the maximum value and the minimum value of the average value Pjz or the value corresponding to the average value Pjz are obtained,
Among each pattern, a pattern in which N12j is the smallest to the extent that the maximum value and the minimum value are saturated within the amplification dynamic range is selected as an optimum pattern.
Using the reflected wave data amplified in this optimal pattern and stored in the memory, the buried object is explored,
When there are a plurality of patterns having the minimum saturation level N12j, a pattern having the largest difference Pjz1 between the maximum value and the minimum value is selected as an optimal pattern. .

While moving along the surface of the concealed place where the buried object is buried, radiate electromagnetic waves to the concealed place,
Receives reflected waves from buried objects,
In the buried object exploration method for exploring the buried object in the concealed place based on the time difference between the radiated electromagnetic wave and the received reflected wave,
While moving by a predetermined first distance d, the received reflected wave is amplified and stored in the memory with a plurality of amplification / time patterns that change so that the amplification increases with time. ,
This store operation to the memory is repeated over a predetermined second distance L1,
Corresponding to the average value Pjz or the average value Pjz of the intensity of the reflected wave over the second distance L1 for each position in the depth direction from the surface of the concealment place to the predetermined depth DP1 near the surface for each pattern. Find the value
For each pattern, the maximum value and the minimum value of the average value Pjz or the value corresponding to the average value Pjz are obtained,
Among each pattern, a pattern in which N12j is the smallest to the extent that the maximum value and the minimum value are saturated within the amplification dynamic range is selected as an optimum pattern.
Using the reflected wave data amplified in this optimal pattern and stored in the memory, the buried object is explored,
When there are a plurality of the patterns having the minimum saturation degree N12j, the second distance for each position in the depth direction from the surface of the concealment place to the predetermined depth DP2 where the embedded object exists for each pattern. The average value Qjz of the absolute value of the intensity of the reflected wave over L1 or a value corresponding to the average value Qjz is obtained,
Evaluate the degree of approximation between the predetermined intensity distribution in the depth direction of the reflected wave and the average value Qjz or the value corresponding to the average value Qjz of the absolute value for each pattern;
As a result of the evaluation, among the patterns, the best approximated pattern is selected as the optimal pattern,
A method for exploring an embedded object, comprising: searching for an embedded object using the reflected wave data amplified in the optimum pattern and stored in a memory.

While moving along the surface of the concealed place where the buried object is buried, radiate electromagnetic waves to the concealed place,
Receives reflected waves from buried objects,
In the buried object exploration method for exploring the buried object in the concealed place based on the time difference between the radiated electromagnetic wave and the received reflected wave,
While moving by a predetermined first distance Δd, the received reflected wave is amplified and stored in a memory with a plurality of amplification / time patterns that change so that the amplification increases with time.
This store operation to the memory is repeated over a predetermined second distance L1,
For each pattern, the absolute value Qjz or the average value of the absolute values of the reflected wave over the second distance L1 for each position in the depth direction from the surface of the concealment place to the predetermined depth DP2 where the buried object exists. Find the value corresponding to Qjz,
Evaluate the degree of approximation between the predetermined intensity distribution in the depth direction of the reflected wave and the average value Qjz or the value corresponding to the average value Qjz of the absolute value for each pattern;
As a result of the evaluation, among the patterns, the best approximated pattern is selected as the optimal pattern,
A method for exploring an embedded object, comprising: searching for an embedded object using the reflected wave data amplified in the optimum pattern and stored in a memory.

The approximate degree of evaluation is the difference between the predetermined intensity distribution in the depth direction of the reflected wave and the average value Qjz for each pattern or the value corresponding to the average value Qjz for each position in the depth direction. 8. The method for exploring buried objects according to claim 7, wherein a sum of squares or a value corresponding to the sum is obtained.

Means for radiating electromagnetic waves to a concealed place where the buried object is buried;
An antenna for receiving the reflected wave from the buried object;
Amplifying means for amplifying the output of the antenna with variable amplification;
Means for detecting the moving distance of the antenna;
A first memory for storing a plurality of different amplification degree / time patterns, the amplification degree of which changes so as to increase with the passage of time;
A second memory for storing the output of the amplification means;
In response to the output of the moving distance detecting means, while moving by a predetermined first distance Δd, the amplification degree of the amplifying means is changed and stored in the second memory in each of a plurality of patterns stored in the memory, Amplification degree control means for repeating this store operation over a predetermined second distance L1,
The stored contents of the second memory are read, and for each pattern, the intensity of the reflected wave is measured over the second distance L1 for each position in the depth direction from the surface of the concealment place to a predetermined depth DP1 near the surface. A first calculating means for calculating an average value Pjz or a value corresponding to the average value Pjz;
In response to the output of the first calculation means, second calculation means for calculating the maximum value and the minimum value of the average value Pjz or the value corresponding to the average value Pjz for each pattern;
Selecting means for selecting, as an optimum pattern, a pattern having a minimum value N12j that is saturated within amplifying dynamic range of the amplifying means among the patterns in response to the output of the second calculating means; ,
Look including a means to probe buried object by using the data of the reflected wave is stored in the second memory obtained using the best pattern selected by the selection means,
The selecting means determines the degree of saturation N12j as the sum of numbers N1j and N2j in which the maximum value and the minimum value are equal to the saturation value of the amplification dynamic range.

The selection means, when there are a plurality of the patterns having the minimum saturation level N12j, select a pattern having the maximum difference Pjz1 between the maximum value and the minimum value as an optimal pattern. Item 9. The buried object exploration device according to Item 9 .

When there are a plurality of the patterns having the minimum saturation level N12j, the selection means is provided for each position in the depth direction from the surface of the concealment place to the predetermined depth DP2 where the embedded object exists for each pattern. An average value Qjz of absolute values of reflected wave intensity over the second distance L1 or a value corresponding to the average value Qjz is obtained,
Evaluate the degree of approximation between the predetermined intensity distribution in the depth direction of the reflected wave and the average value Qjz or the value corresponding to the average value Qjz of the absolute value for each pattern;
As a result of the evaluation, among the patterns, the best approximated pattern is selected as the optimal pattern,
10. The buried object searching device according to claim 9, wherein the buried object is searched using the reflected wave data amplified in the optimum pattern and stored in the memory.

Means for radiating electromagnetic waves to a concealed place where the buried object is buried;
An antenna for receiving the reflected wave from the buried object;
Amplifying means for amplifying the output of the antenna with variable amplification;
Means for detecting the moving distance of the antenna;
A first memory that stores a plurality of mutually different amplification degrees and time patterns in which the amplification degree changes so as to increase with the passage of time;
A second memory for storing the output of the amplification means;
In response to the output of the moving distance detecting means, while moving by a predetermined first distance Δd, the amplification degree of the amplifying means is changed and stored in the second memory in each of a plurality of patterns stored in the memory, Amplification degree control means for repeating this store operation over a predetermined second distance L1,
The stored contents of the second memory are read, and for each pattern, the intensity of the reflected wave is measured over the second distance L1 for each position in the depth direction from the surface of the concealment place to a predetermined depth DP1 near the surface. A first calculating means for calculating an average value Pjz or a value corresponding to the average value Pjz;
In response to the output of the first calculation means, second calculation means for calculating the maximum value and the minimum value of the average value Pjz or the value corresponding to the average value Pjz for each pattern;
Selecting means for selecting, as an optimum pattern, a pattern having a minimum value N12j that is saturated within amplifying dynamic range of the amplifying means among the patterns in response to the output of the second calculating means; ,
Means for exploring an embedded object using reflected wave data stored in the second memory obtained by using the optimum pattern selected by the selection means,
The selecting unit selects, as an optimum pattern, a pattern having a maximum difference Pjz1 between the maximum value and the minimum value when there are a plurality of the patterns having the minimum saturation level N12j. Object exploration equipment.

Means for radiating electromagnetic waves to a concealed place where the buried object is buried;
An antenna for receiving the reflected wave from the buried object;
Amplifying means for amplifying the output of the antenna with variable amplification;
Means for detecting the moving distance of the antenna;
A first memory that stores a plurality of mutually different amplification degrees and time patterns in which the amplification degree changes so as to increase with the passage of time;
A second memory for storing the output of the amplification means;
In response to the output of the moving distance detecting means, while moving by a predetermined first distance Δd, the amplification degree of the amplifying means is changed and stored in the second memory in each of a plurality of patterns stored in the memory, Amplification degree control means for repeating this store operation over a predetermined second distance L1,
The stored contents of the second memory are read, and for each pattern, the intensity of the reflected wave is measured over the second distance L1 for each position in the depth direction from the surface of the concealment place to a predetermined depth DP1 near the surface. A first calculating means for calculating an average value Pjz or a value corresponding to the average value Pjz;
In response to the output of the first calculation means, second calculation means for calculating the maximum value and the minimum value of the average value Pjz or the value corresponding to the average value Pjz for each pattern;
Selecting means for selecting, as an optimum pattern, a pattern having a minimum value N12j that is saturated within amplifying dynamic range of the amplifying means among the patterns in response to the output of the second calculating means; ,
Means for exploring an embedded object using reflected wave data stored in the second memory obtained by using the optimum pattern selected by the selection means,
When there are a plurality of the patterns having the minimum saturation level N12j, the selection means is provided for each position in the depth direction from the surface of the concealment place to the predetermined depth DP2 where the embedded object exists for each pattern. An average value Qjz of absolute values of reflected wave intensity over the second distance L1 or a value corresponding to the average value Qjz is obtained,
Evaluate the degree of approximation between the predetermined intensity distribution in the depth direction of the reflected wave and the average value Qjz or the value corresponding to the average value Qjz of the absolute value for each pattern;
As a result of the evaluation, among the patterns, the best approximated pattern is selected as the optimal pattern,
Using the reflected wave data amplified in this optimal pattern and stored in the memory, An exploration device for buried objects characterized by exploration.

The selection means is the sum of the squares of the differences at each position in the depth direction between the predetermined intensity distribution and the average value Qjz of the absolute value for each pattern or a value corresponding to the average value Qjz, or the 14. The exploration device for buried objects according to claim 11 or 13, wherein a value corresponding to the sum is calculated and an approximation degree is evaluated.

Means for radiating electromagnetic waves to a concealed place where the buried object is buried;
An antenna for receiving the reflected wave from the buried object;
Amplifying means for amplifying the output of the antenna with variable amplification;
Means for detecting the moving distance of the antenna;
A first memory for storing a plurality of different amplification degree / time patterns, the amplification degree of which changes so as to increase with the passage of time;
A second memory for storing the output of the amplification means;
A third memory for storing a predetermined intensity distribution in the depth direction of the reflected wave;
In response to the output of the moving distance detecting means, while moving by a predetermined first distance Δd, the amplification degree of the amplifying means is changed and stored in the second memory in each of a plurality of patterns stored in the memory, Amplification degree control means for repeating this store operation over a predetermined second distance L1,
The stored contents of the second memory are read, and for each pattern, the second distance L1 for each position in the depth direction from the surface of the concealment place to at least a predetermined depth DP2 in the vicinity where the embedded object is embedded. A first calculation means for calculating an average value Qjz of the absolute value of the intensity of the reflected wave or a value corresponding to the average value Qjz and storing the calculated value in a fourth memory;
Based on the predetermined intensity distribution stored in the third memory and the stored content read from the fourth memory, the predetermined intensity distribution, and the average value Qjz or the average value Qjz of the absolute values for each pattern An evaluation means for evaluating the degree of approximation with the value corresponding to
In response to the output of the evaluation means, a selection means for selecting, as an optimal pattern, a pattern that has the best approximation among the patterns,
And a means for exploring the buried object using the reflected wave data stored in the second memory obtained using the optimum pattern selected by the selecting means.

The evaluation means is the sum of the squares of the differences at each position in the depth direction between the predetermined intensity distribution and the average value Qjz of the absolute value for each pattern or a value corresponding to the average value Qjz, or the 16. The buried object exploration device according to claim 15, wherein a value corresponding to the sum is calculated.