JP3813108B2 - Utility pole measurement method and utility pole measurement program using image processing technology, and recording medium recording this program - Google Patents

Description

【００４３】
［２］電柱−ケーブル平面の法線ベクトルＮ
【００４４】
【数２】

【００４５】
［３］点Ａのベクトル表現Ａ
【００４６】
【数３】

【００４７】
［４］フィルム原点ｄ
【００４８】
【数４】

【００４９】
［５］点Ａのフイルム上での像ａ
【００５０】
【数５】

【００５１】
［６］基準点Ｐb
【００５２】
【数６】

【００５３】
［７］フイルム平面軸の単位方向ベクトルｌｘ，ｌｙ
【００５４】
【数７】

【００５５】
（１．３）条件式の設定
さらに、上記ベクトル表現の間には以下のような条件式が成立する。
【００５６】
［１］点Ａは電柱−ケーブル平面上に存在する。
【００５７】
（Ａ−Ｐb）・Ｎ＝０ …（８）
（‘・’はベクトルの内積、以下同様）
［２］点ａはフィルム平面上に存在する。
【００５８】
（ａ−ｄ）・ｎ＝０ …（９）
（１．４）フイルム平面から３次元空間への変換式
以上の準備の元に、フイルム上の点（Ｌｘ，Ｌｙ）から３次元空間上の点（Ｘ，Ｙ，Ｚ）を求める計算式を展開すると、以下の結果が得られる。
【００５９】
【数８】

【００６０】
ここで、電柱上での算出式（座標ＬｙとＺとの関係）を求める。式（１０）において、フィルム上での点を電柱上での点、すなわちＬｘ＝０となる点のみに着目すると、同式は次のようになる。
【００６１】
【数９】

【００６２】
（１．５）画像平面から３次元空間への変換式
フィルム座標系Ｌｘ−Ｌｙ（単位はメートル）を画像座標系ｘ−ｙ（単位は画素アドレスで実数値）で置き換えるものとする。すなわち
【００６３】
【数１０】

【００６４】
とし、ｍ：ｄ／αとすると、電柱上での変換式（１１）は次のようになる。
【００６５】
【数１１】

【００６６】
この式で、値ｍを「レンズ比率」と呼ぶものとする。ｍは未知数である。
【００６７】
（１．６）原点地上高の導入
上記までの式の展開においては、３次元空間上での座標値Ｚの値は全てＸ−Ｙ−Ｚ座標系の原点、すなわちカメラレンズ中心に対する上下方向の高さ（メートル）で考えてきた。
【００６８】
ここで、Ｚの値を地表（地上高０メートル）からの高さで与えることとする。このために原点地上高（レンズ中心の地表からの高さ）Ｚb（単位はメートル）を導入する。これにより（１２）式のＺの計算式は以下のようになる。
【００６９】
【数１２】

【００７０】
同様に（１０）式は以下のようになる。
【００７１】
【数１３】

【００７２】
（１．７）未知数の自動計算
画像上の電柱上での座標ｙから実際の地上高Ｚを求める計算式（１３）において、分子と分母をcosθ（≠０）で割ると、次式が得られる。
【００７３】
【数１４】

【００７４】
この式で計算パラメータは以下の４つであり、これらの値を決定しない限り、ｙからＺを求めることはできない。
【００７５】
Ｄ：カメラ距離
ｍ：レンズ比率
θ：カメラ仰角（式（１５）ではtanθ）
Ｚb：原点地上高
このうち、レンズ比率ｍは事実上実測不可能で、他のパラメータは実測可能である。先ず、カメラ距離Ｄについてはカメラ撮影現場での実測値を用いるものとする。残り２つのパラメータの原点地上高Ｚbおよびカメラ仰角θについては、片方を既知とすれば、もう一方は式（１５）の連立方程式を立てることにより算出できる。
【００７６】
ここで原点地上高Ｚbを固定値（例えば１．５または１．７メートルなど）とするか、あるいは実測値を用いることとすれば、（１５）式における未知数はｍとθとなる。そこで、この２つの未知数を求めるため、地上高既知の２組の点対（ｙ1，Ｚ1）および（ｙ2，Ｚ2）に対する２つの式
【００７７】
【数１５】

【００７８】
を連立方程式とみなして、これをｍとtanθについて解く。
【００７９】
tanθの算出式は以下のようになる。
【００８０】
Ｐtan²θ＋Ｑtanθ＋Ｒ＝０ …（１７）
ただし、
Ｐ＝Ｄ（Ｈ1ｙ1−Ｈ2ｙ2）
Ｑ＝（ｙ1−ｙ2）（Ｄ2−Ｈ1Ｈ2）
Ｒ＝Ｄ（Ｈ1ｙ2−Ｈ2ｙ1）
ここで、
Ｈ1＝Ｚ1−Ｚb
Ｈ2＝Ｚ2−Ｚb
この２次方程式を解いてtanθ（すなわちθ）が算出される。ただし、θは解が２つ存在するので、標準角度（例えば２０°）に近い方を取るものとする（解のもう一方の値はこの値からはかけ離れた値となる）。
【００８１】
また、レンズ比率ｍは、例えば式（１６）の第１式から次のように算出される。
【００８２】
【数１６】

【００８３】
逆に、カメラ仰角θを既知とした場合、原点地上高Ｚbの算出式は以下のようになる。
【００８４】
ＰＺb²＋ＱＺb＋Ｒ＝０ …（１９）
ただし、
Ｐ＝（ｙ1−ｙ2）tanθ
Ｑ＝（ｙ1−ｙ2）｛Ｄ（tan²θ−１）−（Ｚ1＋Ｚ2）tanθ｝
Ｒ＝（ｙ1−ｙ2）tanθ（Ｚ1Ｚ2−Ｄ²）＋Ｄ｛ｙ1Ｚ2−ｙ2Ｚ1−tan²θ（ｙ1Ｚ1−ｙ2Ｚ2）｝
この２次方程式を解いてＺbが算出される。ただし、Ｚbは解が２つ存在するので、標準−原点地上高（例えば１．７メートル）に近い方を取るものとする（解のもう一方の値はこの値からはかけ離れた値となる）。また、レンズ比率ｍは同様に（１９）式から同様に算出される。
【００８５】
なお、原点地上高Ｚbおよびカメラ仰角θのどちらを既知とし、どちらを未知としてもよい。両者とも未知として、地上高既知の３点を用いて３元連立方程式を立てることも考えられるが、この場合は連立方程式の解法が極めて困難となり、実用的でない。
（１．８）電柱計測に特化した補正
電柱表面はテーパによって鉛直方向から一定の割合で傾いている物がある。このような電柱を計測する場合、特に電柱の近くから急角度に見上げて当該電柱を撮影すると、電柱表面の地上高Ｚに誤差が生じる。いま電柱表面の傾き角度をαとする時、これを考慮した地上高Ｚは図５より、
【００８６】
【数１７】

【００８７】
で求められる。
【００８８】
ケーブルには太さがあり、特に電柱の近くから急角度に見上げて当該電柱を撮影すると、図６に示すように、ケーブルの両端からレンズ中心へ入射した光は平行に入射しないため、（２０）式から算出される地上高差をケーブル外径とすると、実際の値より大きく算出されることとなる。いまケーブル下端からの入射光の水平線に対する入射角度をθ1、ケーブル上端からの入射光の水平線に対する入射角度をθ2、（２０）式から算出されるケーブル下端の地上高をＺ1、（２０）式から算出されるケーブル上端の地上高をＺ2、ケーブルの真の外径をｒとすると、
【００８９】
【数１８】

【００９０】
で算出できる。ただし、
【００９１】
【数１９】

【００９２】
（１．９）注目平面の移動
電柱にケーブルが張られる場合、電柱に直接ではなく、電柱−ケーブル平面に対して直角手前に（または後方に）突出した支持器具（突出物）を介して張られる場合がある。図７はこれを説明する図である。同図において、点Ｐ（ベクトル表現、以下同様）は電柱−ケーブル平面上の点Ｐ0が電柱−ケーブル平面に対して垂直に手前に突出した図を表している。ここで、Ｐを通りかつ電柱−ケーブル平面に平行な面を考え、これを注目平面と呼ぶものとする。注目平面上での座標計算は以下のようになる。
【００９３】
いま、直線ＯＰと電柱−ケーブル平面との交点をＰ’とし、ＰおよびＰ’の地上高をそれぞれＺpおよびＺp’とした場合（図７）、Ｚp’は式（１３）より算出できる。
【００９４】
また、突出点Ｐの地上高Ｚpは既知であるとする（突出物の根もとである点Ｐ0の地上高として式（１３）より算出できる）。このとき
【００９５】
【数２０】

【００９６】
を突出率と呼ぶものとする（図８）。注目平面が電柱−ケーブル平面の場合、α＝１である。
【００９７】
これにより、注目平面上の任意の点Ｐの（Ｘ，Ｙ，Ｚ）座標は、Ｐが電柱−ケーブル平面上に存在するものとして算出した座標（Ｘ’，Ｙ’，Ｚ’）を用いて以下のように計算される。
【００９８】
【数２１】

【００９９】
（１．１０）電柱−ケーブル平面角φの算出
角度φは実測値として与えることもできるが、精度の向上を図るため、また実測作業の簡素化を図るため、以下のようにして自動計算するものとする。
【０１００】
いま、同一ケーブル上の２点など、地上高が同一の画像上の点をＰ（ｘ1，ｙ1）およびＰ（ｘ2，ｙ2）とし、これを（１５）式に代入して得られるそれぞれの地上高が等しいことから、tanφ（したがってφ）は以下のように計算される。
【０１０１】
【数２２】

【０１０２】
（１．１１）電柱上の２点の画像処理による抽出
前記（１．７）で述べたように、カメラ距離Ｄと、カメラ仰角θ（または原点地上高Ｚb）の２つの値を実測し、この２つの値を用いてレンズ比率ｍおよび原点地上高Ｚb（またはカメラ仰角θ）を計算する場合、電柱上の地上高既知の２点を指定する必要がある。
【０１０３】
指定する２点としては、地上高が既知である地上高測定棒の節部または間隔が既知である電柱足場ボルトの間隔を用いる。地上高測定棒の節部および電柱上の足場ボルトは画像処理技術を用いて算出する。
【０１０４】
［１］地上高測定棒の節部の算出
地上高測定棒（ほぼ垂直に立っているものとする）は全体が同一色（黄色など）で、その上に一定間隔で別の色の節部が存在する。節部の算出に当たっては、マニュアル指定された測定棒上の一点（指定点と呼び、節部上にはないとものとする）をもとに、上下方向に指定点と同一色を持つ画素を順次探索し、節部など別の色の領域にぶつかった場合はさらにその上の領域を探索し、同一色領域を算出する。同一色領域と同一色領域との関の別の色の領域を測定棒節部として認識する。
【０１０５】
ここで、ある点Ｐに対し、Ｐの上側（または下側）の画素行に存在する点を探索するには、Ｐに８隣接し、しかも指定点の色に最も近いものを選択する。
【０１０６】
［２］電柱上の足場ボルトの算出
予め、足場ボルトの写ったいくつかの画像から、足場ボルトの付け根部分を中心とする小さな画像領域を切り出して登録しておく。任意画像からの足場ボルトの自動抽出に当たっては、画像上のそれぞれの点において登録画像とのパタンマッチング処理を行ない、マッチング度が高い点を足場ボルトが存在する位置として抽出する。
【０１０７】
（２）本発明の第２の実施の形態に関わる自動抽出ロジックの原理
ケーブル図形の両側輪郭線を直線として抽出し、それに基づいてケーブル外径を算出する手法について述べる。
【０１０８】
図９に示すように、写真画像において、外径を求めるケーブル上で中心線に近い２点Ｐ1およびＰ2を指定する。これによりケーブルを含みかつ上下に広がった長方形領域（同図）を自動的に選択する。この領域画像に対し、以下のような画像処理を施し、ケーブル外径を算出する。
【０１０９】
［１］色成分画像の算出
領域画像をＲ（赤）成分、Ｇ（緑）成分およびＢ（青）成分の３つの色成分に分け、それぞれをもとの領域画像と同サイズの白黒濃淡画像として算出する。
【０１１０】
［２］画像の微分
それぞれの色成分画像を微分する。微分オペレータには、例えばＳｏｂｅｌオペレータを用いる。
【０１１１】
［３］微分画像の統一
３つの微分画像に関し、各画素ごとに最大値を求め、これを最終的な微分画像とする。
【０１１２】
［４］直線当てはめ
微分画像上において、線分Ｌ（Ｐ1，Ｐ2）を長方形領域の範囲内で少しづつ上下に移動させ、かつそれぞれの場所で線分を線分中点の周りに左右に少しづつ回転させる。このそれぞれの線分と微分画像とのマッチング（直線当てはめ）を行なう。
【０１１３】
いま、移動・回転されて線分Ｌが図１０のような状態になっているとする。このときの直線当てはめのマッチング度は、直線の横方向の各画素アドレスにおける画素値の和として求められる。ここで同図において、点Ｐの画素値は、Ｐの上下の画素ＰaおよびＰbからＰまでの距離をａ，ｂ（ａ＋ｂ＝１）として、ＰaおよびＰbの画素値の比例配分
（Ｐの画素値）＝（Ｐaの画素値）×ｂ＋（Ｐbの画素値）×ａ
で求められる。
【０１１４】
［５］マッチング度最大値の位置検出
線分を上記のように移動・回転させながら当てはめのマッチング度を求め、領域の上部および下部で、それぞれマッチング度が最大となる位置Ｌ1およびＬ2を求める。
【０１１５】
［６］ケーブル外径の計算
上記で求まる２つの線分Ｌ1およびＬ2に対して図１１のような台形を求め、台形中心線Ｌcの長さをＬ1とＬ2の距離として算出し、これをケーブル外径とみなす。
【０１１６】
（３）本発明の第３の実施の形態に関わる計測方法の原理
電柱の全体像（または大部分）を写し、かつ写真上での各点の地上高が、例えば前記の手法により、計測可能な画像を基本画像とする。また、該電柱の一部分をズームアップし、かつ基本画像と重なり部分をもたせて撮影した画像を付帯画像とする。
【０１１７】
このとき、基本画像上の重なり部分での２つの点Ｐ1およびＱ1（両者はなるべく離れていた方が精度は高い）を、付帯画像上の同一の点Ｐ2およびＱ2に対応させる。ここで、点Ｐ2およびＱ2の地上高は、それぞれ点Ｐ1およびＱ1の地上高と同一であり、既知である。
【０１１８】
すなわち、前記の手法を用いて、点Ｐ2およびＱ2の位置座標と地上高から、付帯画像に関するレンズ比率ｍおよびカメラ仰角θが計算できる。カメラ距離Ｄおよび原点地上高Ｚbは、基本画像と同じ値を用いる。これにより、付帯画像上での任意の位置の地上高（したがってケーブル外径など）が計測できることとなる。
【０１１９】
なお、図３で示した写真撮影を除いた処理の手順をコンピュータのプログラムで構成し、そのプログラムをコンピュータに実行させることができることは言うまでもなく、コンピュータにその処理の手順を実行させるためのプログラムを、そのコンピュータが読み取り可能な記録媒体、例えば、ＦＤ（フロッピーディスク（登録商標））や、ＭＯ、ＲＯＭ、メモリカード、ＣＤ、ＤＶＤ、リムーバブルディスクなどに記録して、保存したり、配布したりすることが可能である。また、上記のプログラムをインターネットや電子メールなど、ネットワークを通して提供することも可能である。
【０１２０】
【発明の効果】
本発明によれば、以上のように構成したため、目視による装柱物測定が困難である場合であっても、装柱物の写真を撮影することで実際の大きさと略合致した装柱物の測定を行うことができるので、人的誤差を含まない、さらに正確な電柱の強度設計が可能になる。
【図面の簡単な説明】
【図１】本発明の実施の形態に係る装柱物の計測方法が適用される、電柱と線条、電力機器に係る架空線路の概略構成を示す側面図である。
【図２】（ａ）はケーブル外径の真値と、従来の電柱装柱物の計測方法によるケーブル外径の値、ケーブル仕様表の値を比較したグラフ、および（ｂ）はケーブル外径の真値と、本発明の実施の形態に係る装柱物の計測方法によるケーブル外径の値、ケーブル仕様表の値を比較したグラフである。
【図３】本発明の実施の形態による電柱計測方法の処理の手順を示すフローチャートである。
【図４】本発明の第１の実施の形態に関わる電柱計測原理を説明する図であって、カメラレンズ中心を原点とし、電柱・ケーブルが張る３次元空間に対して数学モデルを構成し、フィルム画像上の点（２次元）を３次元空間上の点に写像する原理を説明するための図である。
【図５】本発明の第１の実施の形態に関わる計測方法を説明する図であって、画像において、指定された点の地上高を算出するための原理を示し、電柱表面の鉛直面からの傾きを考慮した、電柱表面上の地上高算出を説明する図である。
【図６】本発明の第１の実施の形態に関わる計測方法を説明する図であって、画像において、２点が指定されたケーブルの外径を自動算出するための原理を示し、ケーブルの太さと撮影角度を考慮したケーブル外径の算出を説明する図である。
【図７】図４の補助となる図であって、電柱にケーブルが、電柱−ケーブル平面に対して直角手前に（または後方に）突出した支持器具を介して張られている場合の電柱計測原理を説明する図である。
【図８】図７の補助となる図であって、注目平面の突出度の計算式算出を説明する図である。
【図９】本発明の第２の実施の形態に関わる計測方法を説明する図であって、画像において、２点が指定されたケーブルの外径を自動算出するための原理を示し、指定された２点から画像処理の対象となる長方形領域を算出する説明図である。
【図１０】本発明の第２の実施の形態に関わる計測方法を説明する図であって、画像において、２点が指定されたケーブルの外径を自動算出するための原理を示し、１本の線分に対する微分画像とのマッチングを求める際の画素値を算出する説明図である。
【図１１】本発明の第２の実施の形態に関わる計測方法を説明する図であって、画像において、２点が指定されたケーブルの外径を自動算出するための原理を示し、得られた２本の輪郭線からケーブル外径を算出する説明図である。
【符号の説明】
１…電柱
２…線条（ケーブル）
３…電力機器
４…地上高[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring the horizontal height of a pole, the outer diameter of a pole, the horizontal projected cross-sectional area of a power device, etc. used in the design of a power pole on which a pole, such as a wire or power equipment is installed.
[0002]
[Prior art]
As a conventional measuring method of this kind, when measuring the ground height of a pole pole, there is known a method of measuring by extending a rod that can measure the distance from the ground to each pole by visual measurement. ing. Also, when measuring the horizontal projection cross-sectional area of the outer diameter of the wire and power equipment, etc., select the object with the closest value by comparing the visual measurement result from the ground with the specification table of the pillar. It is known to do.
[0003]
According to such a method for measuring utility poles, the ground height and size of the utility poles can be determined, and appropriate strength design of the utility poles can be performed.
[0004]
[Problems to be solved by the invention]
However, the above measuring method has the following inconveniences when there is a large measurement error in the horizontal projection cross-sectional area of the columnar object, the outer diameter of the filament, the electric power equipment, etc. by visual observation.
[0005]
In other words, when visual measurement is difficult and the error is large, an incorrect pillar may be selected when compared with the column usage table.
[0006]
Therefore, an object of the present invention is to take a picture of a pillar and use an image processing technique, without measuring the horizontal height of the pillar, the outer diameter of the filament, the horizontal projection cross section of the power equipment, etc. by visual observation. It is to provide a method for measuring a pillar.
[0007]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention is based on a utility pole photograph taken together with a ground height measuring rod or a scaffold bolt on a utility pole. A measuring method for calculating pole information including two or more, and a procedure for describing a three-dimensional space constituted by a power pole, a line, and a photographing means for the power pole photograph as one mathematical model, A procedure for obtaining two-dimensional position information on an image by automatically extracting ground height known points including a position of a node bolt on the ground height measuring rod or a scaffold bolt on the utility pole by an image processing technique; A procedure for obtaining position information on the three-dimensional space by applying position information to the mathematical model, and a procedure for calculating the pillar information from the electric pole photographic image based on the position information on the three-dimensional space. A picture characterized by having And means for utility pole measurement method using the processing techniques.
[0008]
Alternatively, in the electric pole measuring method using the image processing technique, in the procedure of calculating the pole information from the electric pole photograph image based on the position information in the three-dimensional space, an image including a line shape in the vicinity of the measurement unit An electric pole measuring method using an image processing technique characterized by differentiating a region and extracting a shape contour line as two straight lines and calculating a line outer diameter as a distance between the two straight lines.
[0009]
Alternatively, in the utility pole measurement method using the image processing technique described above, the utility pole photograph includes a basic photograph that includes all or most of the utility pole and has at least two ground height known points, and zooms in on a portion of the utility pole and the fundamental The procedure for calculating the pole information from the electric pole photograph image based on the position information in the three-dimensional space, which consists of two photographs of the photograph and an accompanying photograph having an overlapping part, is based on two points on the basic photograph in the overlapping part. A pole measuring method using an image processing technique, wherein the column information of an arbitrary point is calculated with respect to the incidental photo whose attachment column information is unknown by corresponding to the same two points on the incidental photo As a means.
[0010]
Alternatively, in the utility pole measurement method using the image processing technique described above, in the procedure of calculating the pole information from the utility pole photographic image based on the position information in the three-dimensional space, the utility pole photograph is steep from the vicinity of the utility pole. If the electric pole is photographed while looking up, an image characterized by correcting the calculated athletic information in consideration of one or both of the inclination of the electric pole plane from the vertical plane and the thickness of the cable outer diameter An electric pole measuring method using a processing technique is used as means.
[0011]
Alternatively, an electric pole measurement program using an image processing technique, which is a program for causing a computer to execute the procedure in the electric pole measurement method using the above image processing technique, is used as means.
[0012]
Alternatively, an image processing technique characterized in that a procedure for the utility pole measurement method using the above image processing technique is used as a program for causing a computer to execute the program, and the program is recorded on a recording medium readable by the computer. A recording medium on which the utility pole measurement program is recorded is used as means.
[0013]
In the present invention, it is difficult to measure the pillar by the conventional measurement method in which the outer diameter of the wire and the horizontal projected cross-sectional area of the power equipment are specified by checking the measurement from the ground and the specification table of the pillar. In such cases, such as when the measurement error is large or due to an artificial measurement error, a telephone pole photograph including the pole is taken, and the ground height known point is automatically extracted using image processing technology. By measuring the pillar, it is possible to measure the pillar that substantially matches the actual size, and to provide a more accurate method for measuring the pillar, and thus a method for designing the utility pole.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
[0015]
FIG. 1 is a side view showing a schematic configuration of an overhead line related to a wire and power equipment to which a method for measuring a utility pole according to an embodiment of the present invention is applied. In FIG. 1, 1 is a utility pole, 2 is a wire (hereinafter referred to as a cable), 3 is a power device, and 4 is a ground clearance.
[0016]
The value of wind pressure load calculation of the utility pole 1 in this overhead line is calculated by the equation (a). However, in Formula (a), n is the number of cables installed, m is the number of installed power devices, d _n Is the outer diameter of the n-th cable, h _n Is the ground clearance of the n th line, A _m Is the horizontal cross-sectional area of the mth power device, h _m Is the ground height of the m-th power equipment, S is the span length between utility poles, K is the wind pressure load per unit area, P _p Represents the wind pressure load received by the utility pole itself.
[0017]
Wind pressure load applied to utility pole = K x S x Σ (d _n ・ H _n ) + K × Σ (A _m ・ H _m ) + P _p ... (a)
Now let the true value of the cable outer diameter be d _s The outer diameter of the specification table is d _a , D _b (D _a <D _b ), The outer diameter measured by eye measurement is d _e The outer diameter measurement value according to the present invention is d _t And d _e , D _t D _a Larger, d _b It is a smaller value.
[0018]
In this aerial line, when it is difficult to measure the outer diameter of the cable, when the conventional measuring method for utility poles is applied as it is, d _e Is the true value of the cable outer diameter d _s According to another outer diameter d in the specification table _b The value approaches to. That is, | d _a -D _e | >> | d _b -D _e Therefore, the actual cable outer diameter is d _b Therefore, an outer diameter that is larger than the true value of the cable outer diameter is adopted (see FIG. 2A).
[0019]
Therefore, in the conventional measuring method for pole poles that determines the cable outer diameter by visual measurement, d in equation (a) _n Becomes excessive, and as a result, an excessive wind pressure load is expected. Moreover, since the size of the utility pole 1 is increased or decreased by one rank in terms of the result of the utility pole measurement result, it is desirable that the result of the utility pole measurement is a more accurate value from an economic point of view.
[0020]
In the method for measuring utility pole equipment according to the embodiment of the present invention, d _t Is the measured value d of the cable outer diameter by the conventional measuring method _b According to another outer diameter d in the specification table _a The value approaches to. That is, | d _a -D _t | <| D _b -D _t Therefore, the actual cable outer diameter is d _a True value of cable outer diameter d _s Can be employed (see FIG. 2B).
[0021]
Therefore, according to the measuring method of the utility pole according to the embodiment of the present invention, the measurement result of the pole is not an excessive value even when it is difficult to measure the pole by visual inspection. The value can be made to substantially match the true value of the pillar. As a result, economical design is secured in the design of the utility pole using the measurement result of the utility pole body according to the embodiment of the present invention.
[0022]
FIG. 3 shows the flow of a processing procedure that is the basis of the method for measuring a utility pole structure according to the embodiment of the present invention.
[0023]
First, using an imaging means such as a camera, a utility pole photograph is taken together with a ground height measuring rod or a scaffolding bolt on a utility pole. This electric pole photograph is taken into image processing means such as a computer.
[0024]
A ground height known point including a node on the ground height measuring rod or a scaffold bolt position on the power pole in the captured electric pole photographic image is automatically extracted by an image processing technique to obtain two-dimensional position information on the image.
[0025]
In both cases (either the above procedure or the present procedure may be performed first), a three-dimensional space composed of utility poles, cables, and utility pole photography means is described as one mathematical model.
[0026]
The two-dimensional position information obtained in the above procedure is applied to the mathematical model described in the same procedure to obtain the position information in the three-dimensional space.
[0027]
Based on the position information in the three-dimensional space calculated in this way, the pole information such as the horizontal projection cross-sectional area of the pole poles such as power equipment etc. calculate.
[0028]
The item for implement | achieving the measuring method of the pole-pillar mounting thing which concerns on embodiment of this invention below is demonstrated in detail.
[0029]
(1) Principle of the measurement method according to the first embodiment of the present invention
(1.1) Definition of terms
FIG. 4 is a measurement principle diagram for configuring the measurement logic according to the present embodiment. A measurement principle (mathematical model) for calculating the point (X, Y, Z) in the three-dimensional space from the point (x, y) on the image will be described with reference to FIG.
[0030]
First, terms for explaining the measurement principle are shown below.
[0031]
[1] Ground / Ground Height: The ground is a specific plane that is horizontal to the earth. The ground height is the height above the ground, and the unit is meters and takes a real value.
[0032]
[2] Three-dimensional space: A real space in which cameras, utility poles, and cables exist, and is expressed in a coordinate system XYZ. The origin is the lens center of the camera. The X-axis is a straight line from the lens center to the utility pole and parallel to the ground. The Y axis is a straight line that is perpendicular to the X axis and parallel to the ground, and exists 90 degrees counterclockwise with respect to the X axis when viewed from above. The Z axis is perpendicular to the ground, and the upward direction is the positive direction. The unit of the coordinate system is a real value in meters.
[0033]
[3] Film plane: A plane on which the utility pole facility is shown as a real image, and is represented by a coordinate system Lx-Ly. The origin is the intersection of the camera optical axis and the film plane, and the unit of the coordinate system is meter and takes a real value.
[0034]
[4] Image (two-dimensional space): A film plane is expressed as an image (a collection of pixels), and is an xy coordinate system in which the center (optical axis position) of the image is the origin. The origin coincides with the film origin. The x-axis is the horizontal direction of the image, and the right direction is the positive direction. The y-axis is the vertical direction of the image, and the upward direction is the positive direction. The unit is a picture element (pixel) and takes a real value.
[0035]
[5] Basic image: An image including the entire image (or most) of the utility pole.
[0036]
[6] Auxiliary image: An image obtained by zooming in on a part of the basic image.
[0037]
[7] Electric pole-cable plane: a three-dimensional space plane specified by the electric pole and cable, and perpendicular to the XY plane.
[0038]
[8] Attention plane: The plane where the measurement target facility exists, and the default attention plane is the utility pole-cable plane. Due to the protrusion attached to the utility pole, the plane of interest translates back and forth with respect to the utility pole-cable plane.
[0039]
[9] Internal parameter: a calculation processing parameter used for calculating the three-dimensional coordinates of the feature point, and has the following types.
Camera elevation angle θ: Camera installation inclination angle with respect to the ground, with upward being a positive angle. The unit is degrees.
Camera distance D: Distance from the center of the camera lens to the front surface of the utility pole. The unit is meters, and real values are taken.
Utility pole-cable plane angle φ: The angle of the utility pole-cable plane in the clockwise direction with respect to the XZ plane and takes a real value of 0 to 180 degrees.
Origin ground height Zb: Ground height (meter) at the origin of the three-dimensional space (center of the camera lens).
Lens ratio m: Ratio when the focal length of the camera is d (meter) and the length per pixel on the image (film) is α (meter)
m = d / α
It is.
[0040]
(1.2) Basic vector setting
Next, in deriving the measurement principle, a basic vector serving as a starting point for developing the calculation formula is set. Each vector on FIG. 4 is expressed as follows. However, the origin of the coordinate system is the center of the lens as shown in FIG. In general, the camera elevation angle θ is not ± 90 °, and the utility pole-cable plane angle φ is not 0 ° or 180 °.
[0041]
[1] Normal vector n of film plane
[0042]
[Expression 1]

[0043]
[2] Telephone pole-cable plane normal vector N
[0044]
[Expression 2]

[0045]
[3] Vector representation A of point A
[0046]
[Equation 3]

[0047]
[4] Film origin d
[0048]
[Expression 4]

[0049]
[5] Image a on film at point A
[0050]
[Equation 5]

[0051]
[6] Reference point Pb
[0052]
[Formula 6]

[0053]
[7] Unit direction vector lx, ly of film plane axis
[0054]
[Expression 7]

[0055]
(1.3) Setting conditional expressions
Further, the following conditional expression is established between the vector expressions.
[0056]
[1] Point A exists on the utility pole-cable plane.
[0057]
(A−Pb) · N = 0 (8)
('·' Is the inner product of vectors, and so on)
[2] Point a exists on the film plane.
[0058]
(Ad) · n = 0 (9)
(1.4) Conversion formula from film plane to 3D space
Based on the above preparation, the following results can be obtained by developing a calculation formula for obtaining a point (X, Y, Z) in a three-dimensional space from a point (Lx, Ly) on the film.
[0059]
[Equation 8]

[0060]
Here, a calculation formula (relationship between coordinates Ly and Z) on the utility pole is obtained. In Expression (10), when focusing on only points on the utility pole, that is, points where Lx = 0, the expression on the film is as follows.
[0061]
[Equation 9]

[0062]
(1.5) Conversion formula from image plane to 3D space
The film coordinate system Lx-Ly (unit is meter) is replaced with the image coordinate system xy (unit is a pixel address and a real value). Ie
[0063]
[Expression 10]

[0064]
And m: d / α, the conversion equation (11) on the utility pole is as follows.
[0065]
[Expression 11]

[0066]
In this equation, the value m is called “lens ratio”. m is an unknown number.
[0067]
(1.6) Introduction of origin ground clearance
In the development of the above formula, all the values of the coordinate value Z in the three-dimensional space have been considered as the height (meter) in the vertical direction with respect to the origin of the XYZ coordinate system, that is, the center of the camera lens.
[0068]
Here, the value of Z is given by the height from the ground surface (0 meters above the ground). For this purpose, an origin ground height (height from the surface of the lens center) Zb (unit is meter) is introduced. Thereby, the calculation formula of Z in the equation (12) is as follows.
[0069]
[Expression 12]

[0070]
Similarly, equation (10) is as follows.
[0071]
[Formula 13]

[0072]
(1.7) Automatic calculation of unknowns
In the calculation formula (13) for obtaining the actual ground height Z from the coordinate y on the utility pole on the image, the following formula is obtained by dividing the numerator and denominator by cos θ (≠ 0).
[0073]
[Expression 14]

[0074]
In this equation, there are the following four calculation parameters. Unless these values are determined, Z cannot be obtained from y.
[0075]
D: Camera distance
m: Lens ratio
θ: Camera elevation angle (tan θ in equation (15))
Zb: Origin ground clearance
Of these, the lens ratio m is practically impossible to measure and other parameters can be actually measured. First, for the camera distance D, an actual measurement value at the camera photographing site is used. With respect to the remaining two parameters, the ground clearance Zb and the camera elevation angle θ, if one is known, the other can be calculated by establishing simultaneous equations of Expression (15).
[0076]
Here, if the origin ground height Zb is set to a fixed value (for example, 1.5 or 1.7 meters) or an actually measured value is used, the unknowns in the equation (15) are m and θ. Therefore, in order to obtain these two unknowns, two equations for two pairs of points (y1, Z1) and (y2, Z2) with known ground height are used.
[0077]
[Expression 15]

[0078]
Is a simultaneous equation, and this is solved for m and tanθ.
[0079]
The formula for calculating tanθ is as follows.
[0080]
Ptan ² θ + Qtanθ + R = 0 (17)
However,
P = D (H1y1-H2y2)
Q = (y1-y2) (D2-H1H2)
R = D (H1y2-H2y1)
here,
H1 = Z1-Zb
H2 = Z2-Zb
By solving this quadratic equation, tan θ (ie, θ) is calculated. However, since there are two solutions for θ, the one closer to the standard angle (for example, 20 °) is assumed (the other value of the solution is a value far from this value).
[0081]
Further, the lens ratio m is calculated as follows from the first expression of Expression (16), for example.
[0082]
[Expression 16]

[0083]
Conversely, when the camera elevation angle θ is known, the calculation formula for the origin ground height Zb is as follows.
[0084]
PZb ² + QZb + R = 0 (19)
However,
P = (y1−y2) tanθ
Q = (y1-y2) {D (tan ² θ-1)-(Z1 + Z2) tan θ}
R = (y1−y2) tan θ (Z1Z2−D ² ) + D {y1Z2-y2Z1-tan ² θ (y1Z1-y2Z2)}
Zb is calculated by solving this quadratic equation. However, since there are two solutions for Zb, the one closer to the standard-origin ground height (eg, 1.7 meters) is assumed (the other value of the solution is far from this value) . Similarly, the lens ratio m is similarly calculated from the equation (19).
[0085]
Note that either the origin ground height Zb or the camera elevation angle θ may be known, and either may be unknown. Although both are unknown, it is conceivable to form a ternary simultaneous equation using three points whose ground height is known, but in this case, it becomes extremely difficult to solve the simultaneous equations, which is not practical.
(1.8) Correction specialized for utility pole measurement
The surface of the utility pole is inclined at a certain rate from the vertical direction due to the taper. When measuring such a utility pole, particularly when looking up at a steep angle from the vicinity of the utility pole and photographing the utility pole, an error occurs in the ground height Z of the utility pole surface. When the inclination angle of the utility pole surface is now α, the ground height Z taking this into account is as shown in FIG.
[0086]
[Expression 17]

[0087]
Is required.
[0088]
The cable has a thickness, and particularly when the electric pole is photographed by looking up at a steep angle from the vicinity of the electric pole, as shown in FIG. 6, the light incident on the lens center from both ends of the cable does not enter in parallel. ) If the ground height difference calculated from the equation is the cable outer diameter, it is calculated to be larger than the actual value. Now, the incident angle with respect to the horizontal line of incident light from the lower end of the cable is θ1, the incident angle with respect to the horizontal line of incident light from the upper end of the cable is θ2, and the ground height at the lower end of the cable calculated from the equation (20) is Z1 and from the equation (20) If the ground clearance at the upper end of the calculated cable is Z2, and the true outer diameter of the cable is r,
[0089]
[Formula 18]

[0090]
It can be calculated by However,
[0091]
[Equation 19]

[0092]
(1.9) Moving the plane of interest
When a cable is stretched on a utility pole, it may be stretched via a support device (protrusion) that projects forward (or rearward) at a right angle to the utility pole-cable plane rather than directly on the utility pole. FIG. 7 is a diagram for explaining this. In the same figure, a point P (vector expression, the same applies hereinafter) represents a diagram in which a point P0 on the utility pole-cable plane protrudes vertically toward the utility pole-cable plane. Here, a plane passing through P and parallel to the utility pole-cable plane is considered, and this is referred to as an attention plane. The coordinate calculation on the plane of interest is as follows.
[0093]
Now, when the intersection of the straight line OP and the utility pole-cable plane is P ′ and the ground heights of P and P ′ are Zp and Zp ′, respectively (FIG. 7), Zp ′ can be calculated from equation (13).
[0094]
Further, it is assumed that the ground height Zp of the protruding point P is known (can be calculated from the equation (13) as the ground height of the point P0 which is the base of the protruding object). At this time
[0095]
[Expression 20]

[0096]
Is called the protrusion rate (FIG. 8). When the plane of interest is a utility pole-cable plane, α = 1.
[0097]
As a result, the (X, Y, Z) coordinates of an arbitrary point P on the target plane are obtained by using the coordinates (X ′, Y ′, Z ′) calculated on the assumption that P exists on the utility pole-cable plane. Calculated as follows:
[0098]
[Expression 21]

[0099]
(1.10) Calculation of utility pole-cable plane angle φ
Although the angle φ can be given as an actual measurement value, it is assumed that it is automatically calculated as follows in order to improve accuracy and simplify the actual measurement work.
[0100]
Now, let the points on the image with the same ground height, such as two points on the same cable, be P (x1, y1) and P (x2, y2), and substitute each of them into equation (15) for each ground Since the heights are equal, tan φ (and hence φ) is calculated as follows:
[0101]
[Expression 22]

[0102]
(1.11) Extraction by image processing of two points on a utility pole
As described in (1.7) above, two values of the camera distance D and the camera elevation angle θ (or the origin ground height Zb) are measured, and the lens ratio m and the origin ground height Zb are measured using these two values. When calculating (or camera elevation angle θ), it is necessary to specify two points on the utility pole whose ground height is known.
[0103]
As the two points to be specified, the distance between the poles of the ground poles whose ground height is known or the nodes of the ground height measuring rod whose ground height is known is used. Scaffold bolts on the nodes of the ground height measuring poles and utility poles are calculated using image processing technology.
[0104]
[1] Calculation of the node of the ground height measuring rod
The ground height measuring rod (assuming that it stands almost vertically) is the same color (yellow, etc.) as a whole, and there are nodes of different colors at regular intervals. In calculating the node, a pixel with the same color as the specified point in the vertical direction is selected based on a point on the measuring bar specified manually (referred to as a specified point and not on the node). The search is sequentially performed, and when a region of another color such as a node is encountered, the region above is further searched to calculate the same color region. Recognize another color area related to the same color area and the same color area as the measuring bar section.
[0105]
Here, in order to search for a point existing in a pixel row on the upper side (or lower side) of a certain point P, a point adjacent to P and closest to the color of the designated point is selected.
[0106]
[2] Calculation of scaffold bolts on utility poles
In advance, a small image region centered on the base portion of the scaffold bolt is cut out and registered from several images showing the scaffold bolt. In the automatic extraction of the scaffold bolt from the arbitrary image, pattern matching processing with the registered image is performed at each point on the image, and a point with a high matching degree is extracted as a position where the scaffold bolt exists.
[0107]
(2) Principle of automatic extraction logic according to the second embodiment of the present invention
A method of extracting the both-side outline of the cable graphic as a straight line and calculating the cable outer diameter based on the extracted line will be described.
[0108]
As shown in FIG. 9, in the photographic image, two points P1 and P2 close to the center line are designated on the cable for obtaining the outer diameter. As a result, a rectangular area including the cable and extending vertically is automatically selected. The area image is subjected to the following image processing to calculate the cable outer diameter.
[0109]
[1] Calculation of color component image
The area image is divided into three color components, an R (red) component, a G (green) component, and a B (blue) component, and each is calculated as a black-and-white gray image having the same size as the original area image.
[0110]
[2] Image differentiation
Differentiate each color component image. For example, a Sobel operator is used as the differential operator.
[0111]
[3] Unification of differential images
Regarding the three differential images, a maximum value is obtained for each pixel, and this is used as a final differential image.
[0112]
[4] Straight line fitting
On the differential image, the line segment L (P1, P2) is moved up and down little by little within the range of the rectangular area, and the line segment is rotated little by little to the left and right around the midpoint of the line segment at each location. Matching (straight line fitting) of each line segment and the differential image is performed.
[0113]
Now, it is assumed that the line segment L is in a state as shown in FIG. The matching degree of the straight line fitting at this time is obtained as the sum of the pixel values at each pixel address in the horizontal direction of the straight line. Here, in the figure, the pixel value of the point P is the proportional distribution of the pixel values of Pa and Pb, where the distances from the pixels Pa and Pb above and below P are a and b (a + b = 1).
(P pixel value) = (Pa pixel value) × b + (Pb pixel value) × a
Is required.
[0114]
[5] Position detection of maximum matching value
The matching degree of fitting is obtained while moving and rotating the line segment as described above, and the positions L1 and L2 at which the matching degree is maximum are obtained at the upper and lower parts of the region, respectively.
[0115]
[6] Calculation of cable outer diameter
A trapezoid as shown in FIG. 11 is obtained for the two line segments L1 and L2 obtained above, the length of the trapezoid center line Lc is calculated as the distance between L1 and L2, and this is regarded as the cable outer diameter.
[0116]
(3) Principle of the measurement method according to the third embodiment of the present invention
An image in which the entire image (or most) of the utility pole is copied and the ground height of each point on the photograph can be measured, for example, by the above-described method is used as a basic image. In addition, an image captured by zooming in on a part of the utility pole and having an overlapping portion with the basic image is used as an auxiliary image.
[0117]
At this time, the two points P1 and Q1 in the overlapping portion on the basic image (both are as far apart as possible are more accurate) correspond to the same points P2 and Q2 on the accompanying image. Here, the ground heights of the points P2 and Q2 are the same as the ground heights of the points P1 and Q1, respectively, and are known.
[0118]
That is, by using the above method, the lens ratio m and the camera elevation angle θ relating to the incidental image can be calculated from the position coordinates of the points P2 and Q2 and the ground height. The camera distance D and the origin ground height Zb use the same values as the basic image. As a result, the ground height (and therefore the cable outer diameter, etc.) at an arbitrary position on the incidental image can be measured.
[0119]
It should be noted that the processing procedure excluding the photography shown in FIG. 3 can be constituted by a computer program, and the program can be executed by the computer. , Record on a computer-readable recording medium, such as FD (floppy disk (registered trademark)), MO, ROM, memory card, CD, DVD, removable disk, etc., and store or distribute It is possible. It is also possible to provide the above program through a network such as the Internet or electronic mail.
[0120]
【The invention's effect】
According to the present invention, since it is configured as described above, even if it is difficult to visually measure the columnar object, by taking a picture of the columnar object, Since the measurement can be performed, it is possible to design the power pole strength more accurately without human error.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a side view showing a schematic configuration of an overhead line related to a utility pole, a wire, and a power device to which a method for measuring a pole article according to an embodiment of the present invention is applied.
FIG. 2A is a graph comparing the true value of the cable outer diameter with the value of the cable outer diameter measured by the conventional method of measuring pole poles, the value in the cable specification table, and FIG. 2B is the cable outer diameter. 6 is a graph comparing the true value of the cable, the value of the outer diameter of the cable according to the measuring method for the pillar according to the embodiment of the present invention, and the value of the cable specification table.
FIG. 3 is a flowchart showing a processing procedure of a utility pole measurement method according to an embodiment of the present invention.
FIG. 4 is a diagram for explaining a power pole measurement principle according to the first embodiment of the present invention, and constructs a mathematical model for a three-dimensional space where a power pole and a cable are stretched with the camera lens center as an origin; It is a figure for demonstrating the principle which maps the point (two dimensions) on a film image to the point on three-dimensional space.
FIG. 5 is a diagram for explaining a measurement method according to the first embodiment of the present invention, showing a principle for calculating the ground height of a specified point in an image, from a vertical surface of a utility pole surface; It is a figure explaining the ground height calculation on the surface of an electric pole in consideration of the inclination of.
FIG. 6 is a diagram for explaining a measurement method according to the first embodiment of the present invention, showing a principle for automatically calculating the outer diameter of a cable in which two points are designated in an image; It is a figure explaining calculation of the cable outer diameter in consideration of thickness and photographing angle.
FIG. 7 is an auxiliary diagram of FIG. 4 and shows the measurement of the utility pole when the cable is stretched on the utility pole via a support device protruding forward (or rearward) at a right angle to the utility pole-cable plane. It is a figure explaining a principle.
FIG. 8 is a diagram that assists FIG. 7 and explains calculation formula calculation of the degree of protrusion of the plane of interest.
FIG. 9 is a diagram for explaining a measurement method according to the second embodiment of the present invention, showing a principle for automatically calculating the outer diameter of a cable in which two points are designated in an image; It is explanatory drawing which calculates the rectangular area | region used as the object of image processing from two points.
FIG. 10 is a diagram for explaining a measurement method according to the second embodiment of the present invention, showing a principle for automatically calculating the outer diameter of a cable in which two points are designated in an image; It is explanatory drawing which calculates the pixel value at the time of calculating | requiring matching with the differential image with respect to this line segment.
FIG. 11 is a diagram for explaining a measurement method according to the second embodiment of the present invention, and shows the principle for automatically calculating the outer diameter of a cable in which two points are designated in an image; It is explanatory drawing which calculates a cable outer diameter from two outlines.
[Explanation of symbols]
1 ... Pole
2 ... Wire (cable)
3 ... Electric power equipment
4 ... Ground clearance

Claims (6)

Measurement to calculate pole information including one or more of the pole height, the outer diameter of the pole pole, and the horizontal projection cross-sectional area of the pole pole from the pole photo taken with the ground height measuring rod or the scaffolding bolt on the pole. A method,
Along with the procedure to describe a three-dimensional space composed of utility poles, filaments and means for taking the utility pole photographs as a mathematical model,
A procedure for obtaining two-dimensional position information on an image by automatically extracting a ground height known point including a node on the ground height measuring rod or a scaffold bolt position on the power pole in the electric pole photograph image by an image processing technique;
Applying two-dimensional position information on the image to the mathematical model to obtain position information on a three-dimensional space;
A method of measuring an electric pole using an image processing technique, comprising: a procedure of calculating the pole information from the electric pole photograph image based on position information in the three-dimensional space. In the utility pole measuring method using the image processing technology according to claim 1,
In the procedure to calculate the pole information from the electric pole photo image based on the position information in the three-dimensional space,
An image processing technique characterized by differentiating an image area including a line shape in the vicinity of the measuring unit, extracting a shape outline as two straight lines, and calculating a line outer diameter as a distance between the two straight lines. Electric pole measurement method using In the utility pole measuring method using the image processing technology according to claim 1,
The utility pole photo consists of two photos: a basic photo that includes all or most of the utility pole and has at least two ground height known points, and a supplementary photo that zooms in on a portion of the utility pole and overlaps with the basic photo.
In the procedure to calculate the pole information from the electric pole photo image based on the position information in the three-dimensional space,
In the overlapping portion, two points on the basic photo are made to correspond to the same two points on the incidental photo, and the columnar information of an arbitrary point is calculated with respect to the incidental photo with unknown columnar information. A utility pole measurement method using image processing technology. In the utility pole measuring method using the image processing technology according to claim 1,
In the procedure to calculate the pole information from the electric pole photo image based on the position information in the three-dimensional space,
When the electric pole photograph is a picture taken of the electric pole looking up at a steep angle from the vicinity of the electric pole, it is calculated by considering one or both of the inclination from the vertical plane of the electric pole plane and the thickness of the cable outer diameter. A utility pole measurement method using an image processing technique characterized by correcting sex information. 5. A utility pole measurement program using an image processing technique, characterized in that a program for causing a computer to execute the procedure in the utility pole measurement method using the image processing technique according to claim 1. A program for causing a computer to execute the procedure in the utility pole measurement method using the image processing technique according to any one of claims 1 to 4,
A recording medium recording a utility pole measurement program using an image processing technique, wherein the program is recorded on a recording medium readable by the computer.

Images