JPH0247539A - Measuring apparatus of reflection information - Google Patents

Measuring apparatus of reflection information

Info

Publication number
JPH0247539A
JPH0247539A JP19844588A JP19844588A JPH0247539A JP H0247539 A JPH0247539 A JP H0247539A JP 19844588 A JP19844588 A JP 19844588A JP 19844588 A JP19844588 A JP 19844588A JP H0247539 A JPH0247539 A JP H0247539A
Authority
JP
Japan
Prior art keywords
light
lens
optical fiber
reflected
measurement target
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP19844588A
Other languages
Japanese (ja)
Inventor
Yuji Tsujimura
裕次 辻村
Jiro Arima
二朗 有馬
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Minolta Co Ltd
Original Assignee
Minolta Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minolta Co Ltd filed Critical Minolta Co Ltd
Priority to JP19844588A priority Critical patent/JPH0247539A/en
Publication of JPH0247539A publication Critical patent/JPH0247539A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N21/4738—Diffuse reflection, e.g. also for testing fluids, fibrous materials
    • G01N21/474—Details of optical heads therefor, e.g. using optical fibres

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

PURPOSE:To measure only a reflected light from an object of measurement by a method wherein a lens whose surface in a prescribed region around the optical axis is covered with a non-reflective film is provided in the middle of an optical system. CONSTITUTION:A light from a light source LS is turned into an intermittent light by a chopper CP and applied to an object TG of measurement through an optical fiber FBO for the light source, a joint element JT, an optical fiber FB and a lens L. Since a circular region LR of the lens L is covered with a non-reflective film L1, the light applied to the lens L from the optical fiber FB is reflected on the surface of the lens L and does not enter an emission opening. Part of the light applied to the object TG of measurement is reflected by the object TG, passed through the lens L, the optical fiber FB, the joint element JT and optical fiber FB1 and FB2 for measurement and projected to filters F1 and F2, and a transmitted light is detected by photosensors S1 and S2. A direct-current component of a detection signal is cut by capacitors C1 and C2 and only the intermittent light from the light source is sent to amplifiers A1 and A2.

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は、反射情報測定装置に関する。[Detailed description of the invention] (Industrial application field) The present invention relates to a reflection information measuring device.

（従来の技術） 反射情報測定装置は、測定対主に光を投光し、測定対象
からの反射光を測光することによって測定対象を分析す
る装置である。従来の反射情報測定装置の一例を第４図
に示す。ＬＳは光源で反射鏡等を用いて光源の光を光源
用光ファイバーＦＢＯの入射端に集光せしめている。Ｍ
は光源光規制板で光源用光ファイバーＦＢＯの入射開口
に入射する光源光を規制している。ＣＰはチエツバ−で
光源光を断続させる。ＭＴはチョッパーＣＰ用のモータ
、ＪＴは光ファイバーの接続部、光源光はＪＴを介して
光ファイバーＦＢで光学ヘッド部ＫＨに送られ、凸レン
ズして集光されて測定対象ＴＧに投光される。測定対象
ＴＧで反射された光はレンズして再度集光されて、光フ
ァイバーＦＢに入射せしめられる。光ファイバーＦＢに
入射した光はＪＴを介して光ファイバーＦＢＩ、ＦＢ２
を通り、特定波長域の光だけを透過させるフィルターＰ
Ｉ　　Ｆ２を透過し、光センサ−ＳＬ、Ｓ２で検出され
る。(Prior Art) A reflection information measuring device is a device that analyzes a measurement target by mainly emitting light and measuring the reflected light from the measurement target. An example of a conventional reflection information measuring device is shown in FIG. LS is a light source that uses a reflecting mirror or the like to condense the light from the light source onto the input end of the optical fiber FBO for the light source. M
The light source light regulating plate regulates the light source light that enters the entrance aperture of the light source optical fiber FBO. The CP uses a checkerboard to intermittent the light from the light source. MT is a motor for the chopper CP, JT is an optical fiber connection part, and the light source light is sent to the optical head part KH via the JT via the optical fiber FB, condensed by a convex lens, and projected onto the measurement target TG. The light reflected by the measurement target TG is condensed again by a lens and is made to enter the optical fiber FB. The light incident on the optical fiber FB passes through the JT to the optical fibers FBI and FB2.
A filter P that allows only light in a specific wavelength range to pass through
It passes through IF2 and is detected by optical sensors SL and S2.

しかし、このような構成では、光ファイバーＦＢから測
定対象に向かって投射した光の一部は測定対象に届く前
にレンズして反射され、このレンズｌ−による反射光が
測定対象ＴＧからの反射光に重畳し光ファイバーＦＢに
入射し、光センサ−Ｓ１．８２で検出される。このレン
ズ反射光の検出信号はすべてノイズとなるので、測定精
度を著しく低下させることとなる。However, in such a configuration, a part of the light projected from the optical fiber FB toward the measurement target is reflected by a lens before reaching the measurement target, and the light reflected by this lens l- is reflected from the measurement target TG. The light is superimposed on the optical fiber FB and is detected by the optical sensor S1.82. Since all of the detection signals of this lens reflected light become noise, measurement accuracy is significantly reduced.

特に、光ファイバーから発射される光の強度分布は光軸
周辺を最大強度とし周辺にいく程強度が弱くなるような
分布であるので、光ファイバーからレンズＬの光軸１呼
返に照射される光は強く、レンズＬの光軸は近で反射さ
れる光は測定対象から反射される測定光と比較して多く
なり、測定精度に与える影響が大きい。In particular, the intensity distribution of the light emitted from the optical fiber is such that the maximum intensity is around the optical axis and the intensity becomes weaker towards the periphery, so the light irradiated from the optical fiber to the optical axis of the lens L is Strongly, the optical axis of the lens L is near, and the amount of light reflected is greater than the measurement light reflected from the object to be measured, which has a large effect on measurement accuracy.

そこでレンズＬの光軸付近で反射された光が投受光用光
ファイバーＦＢに入射しないように、第５図に示すよう
な方法（特開昭６２−８０５３９号）が提案された。第
５図は、レンズＬを傾けて、レンズＬの光軸上から投受
光用の光ファイバーの開口を離すことによって、レンズ
Ｌの光軸付近で反射された光Ｒが光ファイバーの開口に
入射することがなくなった。しかし、レンズＬの反射面
の曲率中心に向かって投光された光はレンズ面で反射さ
れて、来た光路を逆行し、光フアイバー開口に入射する
ので、レンズ面からの反射光が全部測光されなくなった
と云うのではない。従って、レンズの光軸をはずしただ
けでは、レンズ面からの反射光がまだ測定光に混在し、
測定精度に、悪影響を与えていると云う間頭がある。Therefore, in order to prevent the light reflected near the optical axis of the lens L from entering the optical fiber FB for transmitting and receiving light, a method as shown in FIG. 5 (Japanese Patent Laid-Open No. 80539/1983) was proposed. Figure 5 shows that by tilting the lens L and separating the aperture of the optical fiber for transmitting and receiving light from the optical axis of the lens L, the light R reflected near the optical axis of the lens L enters the aperture of the optical fiber. is gone. However, the light projected toward the center of curvature of the reflective surface of the lens L is reflected by the lens surface, travels the optical path backward, and enters the optical fiber aperture, so all of the light reflected from the lens surface is photometered. This is not to say that it has stopped happening. Therefore, if you simply remove the optical axis of the lens, the reflected light from the lens surface will still be mixed into the measurement light.
There is a sense that this has a negative impact on measurement accuracy.

（発明が解決しようとする課題） 本発明は、測定対象からの反射光のみを測光し、光学系
による反射光は測光系に入らないようにすることを目的
とする。(Problems to be Solved by the Invention) An object of the present invention is to photometer only the light reflected from the object to be measured, and to prevent the light reflected by the optical system from entering the photometry system.

（課題を解決するための手段） 測定対象に光を投光し測定対象からの反射光を受光する
光ファイバーと、光軸を中心とした一定領域の表面を非
反射膜で躍ったレンズ又は光軸を中心とした一定領域に
光軸と平行な貫通孔を設けたレンズを、同一光軸となる
ように配置し、上記尤ファイバーからの光を上記レンズ
により測定対象に集光し、測定対象からの反射光を上記
レンズで玉記光ファイバーに集光させるようにした。(Means for solving the problem) An optical fiber that emits light to the measurement target and receives reflected light from the measurement target, and a lens or optical axis whose surface is covered with a non-reflective film in a certain area around the optical axis. A lens with a through hole parallel to the optical axis in a certain area centered on is arranged so that the optical axis is the same, and the light from the above-mentioned optical fiber is focused on the measurement target by the above lens, and the light from the measurement target is The reflected light was focused onto the Yuki optical fiber using the above lens.

（作用） 反射情報測定装置において、集光光学系としてレンズＬ
を光軸が投受光用光ファ・イバーＦＢの光軸と同一とな
るように配置して用いた場合、測定精度に影響を与える
光学系の反射光は、投受光用光ファイバーＦＢＩＩＩＪ
のレンズＬの面を鏡面として考えてみれば良い、第３図
にレンズＬのＦＢ（１１の面を鏡面とした時の状態を示
す、ＦＢ’はＦＢのレンズＩ−の鏡面による像である。(Function) In the reflection information measuring device, the lens L is used as a condensing optical system.
When used with the optical axis aligned with the optical axis of the light emitting/receiving optical fiber FB, the reflected light from the optical system that affects measurement accuracy will be reflected from the light emitting/receiving optical fiber FB
If we consider the surface of lens L as a mirror surface, Figure 3 shows the state when the surface of lens L FB (11) is a mirror surface. FB' is the mirror image of lens I- of FB. .

ＦＢから投光された光のレンズ面による反射光は、この
像ＦＢからの出射光として見ることができる。従って、
レンズＬ面からの反射光が光ファイバーＦＢの開口に入
射する一番外側の光線としては、ＦＢとＦＢ′の同じ側
の開口両外端を結ぶ光線Ｒ１とＲ２となり、この光線Ｒ
１，Ｒ２より外側を通る光線はＦＢの開口には入射され
ない、即ち、光線ＲＩＲ２とレンズＬの鏡面との交点Ｍ
ｌ、Ｍ２を挟む領域ＬＲより外側で反射される光はＦＢ
の開口に入射されないと云うことになる。逆に云えば、
レンズ面からの反射光がＦＢの開口に入射するのは、光
軸を中心とする小さい円形領域ＬＲ内のレンズ面からの
反射光に限定される。従って、本発明は、測定精度を向
上させるには、上記円形領域ＬＲのレンズ面からの反射
光を測定しないようにすれば良いと云う点に着目したも
のである。その第１案が光軸を中心とした上記円形領域
ＬＲのレンズ面を非反射膜（黒色膜）で覆うようにする
方法であり、第２案はレンズの上記円形領域ＬＲに貫通
孔を設ける方法である。これら両案によれば、レンズ面
における反射光が投受光用ファイバーの開口に入射する
ことがなくなり、測定精度を向上させることができる。The light reflected by the lens surface of the light projected from the FB can be seen as the light emitted from the image FB. Therefore,
The outermost rays of light reflected from the lens L surface that enter the aperture of the optical fiber FB are rays R1 and R2 that connect the outer ends of the apertures on the same side of FB and FB', and this ray R
1. The ray passing outside R2 is not incident on the aperture of FB, that is, the intersection point M of the ray RIR2 and the mirror surface of the lens L
The light reflected outside the region LR sandwiching l and M2 is FB.
This means that the light is not incident on the aperture. On the contrary,
The reflected light from the lens surface that enters the aperture of the FB is limited to the reflected light from the lens surface within a small circular region LR centered on the optical axis. Therefore, the present invention focuses on the point that in order to improve measurement accuracy, it is sufficient to avoid measuring the reflected light from the lens surface of the circular region LR. The first method is to cover the lens surface of the circular region LR centered on the optical axis with a non-reflective film (black film), and the second method is to provide a through hole in the circular region LR of the lens. It's a method. According to these two plans, the reflected light on the lens surface will not be incident on the aperture of the light emitting/receiving fiber, and measurement accuracy can be improved.

（実施例） 第１図に本発明の一実施例を示す、第１図において、Ｌ
はレンズで光軸が投受光用光ファイバーＦＢの投光光軸
と一致するように配置され、光軸を中心とする円形領域
ＬＲを同図Ｂに示すように非反射膜Ｌ１で覆っている。(Example) FIG. 1 shows an example of the present invention.
is a lens arranged so that its optical axis coincides with the light emitting optical axis of the light emitting/receiving optical fiber FB, and a circular region LR centered on the optical axis is covered with a non-reflective film L1 as shown in FIG.

投受光用光ファイバーＦＢから投光された光はレンズＬ
で集光されて、測定対象ＴＧに照射される。ＨＭは投光
規制板で投受光用光ファイバーＦＢから出射する光の広
がり角を規制する。光源ＬＳ、光源光規制板Ｍ、チョツ
パーＣＰ、光源用光ファイバーＦＢＯ、モータＭＴ、接
続部ＪＴ、投受光用光ファイバーＦＢ、測光用光ファイ
バーＦＢＩ、ＦＢ２、フィルターＦ１．Ｆ２．光センサ
ーＳ１．Ｓ２は第４図の従来例と同じである。The light emitted from the light emitting/receiving optical fiber FB is sent to the lens L.
The light is focused and irradiated onto the measurement target TG. HM is a light projection regulation plate that regulates the spread angle of light emitted from the light projection/reception optical fiber FB. Light source LS, light source light regulating plate M, chopper CP, optical fiber FBO for light source, motor MT, connection part JT, optical fiber FB for light emission and reception, optical fiber FBI for photometry, FB2, filter F1. F2. Optical sensor S1. S2 is the same as the conventional example shown in FIG.

光源ＬＳからの光は、チョッパーで断続光に変換され、
ＦＢＯ，ＪＴ、ＦＢを通って、レンズＬに投光される。The light from the light source LS is converted into intermittent light by a chopper,
The light passes through FBO, JT, and FB and is projected onto lens L.

レンズＬに投光された光は、レンズして集光され、測定
対象ＴＧに照射される。レンズＬはＦ　Ｂ　ＩＥ［１の
表面の前述した円形領域ＬＲが非反射膜Ｌ１で覆われて
いるので、ＦＢからレンズＬに照射した光は、レンズＬ
面で反射されてＦＢの出射開口に入射することはない。The light projected onto the lens L is focused by the lens and irradiated onto the measurement target TG. Since the aforementioned circular region LR on the surface of the lens L is covered with the non-reflective film L1, the light irradiated from the FB to the lens L is
The light is not reflected by the surface and does not enter the exit aperture of the FB.

Ｊｌｌ定対象ＴＧに照射された光の一部は測定対象ＴＧ
で反射され、この反射光はレンズＬ″ｃ集光され、光フ
ァイバーＦＢの出射開口に集光・入射せしめられる。A part of the light irradiated on the target TG is the target TG to be measured.
This reflected light is focused by the lens L″c, and is focused and incident on the output aperture of the optical fiber FB.

この測定光はＪＴ、ＦＢＩ、ＦＢ２を通り、フィルター
Ｆｌ、Ｆ２に投光される。フィルターＦ１、Ｆ２で測定
すべき波長域の光だけを透過させ、その透過光を光セン
サ−Ｓｌ、Ｓ２で検出し、電気信号に変換する。検出信
号はコンデンサＣ１゜Ｃ２で直流分即ち外光の検出成分
であるバックグランドをカットし、光源からの断続光だ
けを増幅器Ａｌ、Ａ２に送る。This measurement light passes through JT, FBI, and FB2, and is projected onto filters Fl and F2. The filters F1 and F2 transmit only light in the wavelength range to be measured, and the transmitted light is detected by the optical sensors S1 and S2 and converted into an electrical signal. The DC component of the detection signal, that is, the background which is the detection component of external light, is cut off by capacitors C1 and C2, and only the intermittent light from the light source is sent to amplifiers Al and A2.

第２図に本発明の第２実施例を示す。この第２実施例は
、第１図の第１実施例においてＦＢ側のレンズＬ面の円
形領域ＬＲを覆った非反射ｆＰＡｔ、１の代わりに、第
２図に示すように、レンズＬの円形領域ＬＲに光軸と平
行な貫通孔Ｌ２を設けたものである。この孔Ｌ２を設け
た領域ＬＲは前述したように、孔Ｌ２が無かった場合に
レンズＬ面からの反射光がＦＢの開口に入射する領域で
あるから、円形領域ＬＲに孔Ｌ２を設けることによって
、円形領域ＬＲにおけるレンズ面の反射がなくなり、Ｆ
ＢからレンズＬに照射した光が、レンズＬ面で反射され
てＦＢの出射開口に入射することはない。また、ＦＢか
ら投光された光はこの孔Ｌ２を通過して測定対ｇＡＴＧ
に照射され、測定対象ＴＧから反射された光は孔Ｌ２及
びレンズＬを再び通ってＦＢの開口に集光されるので、
第２実施例は第１実施例と比較して感度が良くなる。そ
の他の測定動作は、第１実施例と同じである。FIG. 2 shows a second embodiment of the invention. In this second embodiment, instead of the non-reflection fPAt,1 that covered the circular region LR of the lens L surface on the FB side in the first embodiment of FIG. A through hole L2 parallel to the optical axis is provided in the region LR. As mentioned above, the area LR where this hole L2 is provided is the area where the reflected light from the lens L surface would enter the opening of the FB if there was no hole L2, so by providing the hole L2 in the circular area LR, , the reflection of the lens surface in the circular region LR disappears, and F
The light irradiated from B to the lens L is not reflected by the lens L surface and enters the exit aperture of the FB. In addition, the light emitted from the FB passes through this hole L2 to the measurement target gATG.
The light reflected from the measurement target TG passes through the hole L2 and the lens L again and is focused on the opening of the FB.
The second embodiment has better sensitivity than the first embodiment. Other measurement operations are the same as in the first embodiment.

（発明の効果） 本発明によれば、上述したように、レンズと光ファイバ
ーの光軸を一致させ、レンズの光軸を中心とした小さな
円形領域ＬＲのＦＢ側のレンズ面を非反射膜で覆うか又
はレンズの上記円形領域に貫通孔を設けることによって
、光ファイバーの開口には測定対象からの反射光しか受
光しなくなったので、光学系の反射光によるノイズがな
くなり、測定精度が一段と向上した。(Effects of the Invention) According to the present invention, as described above, the optical axes of the lens and the optical fiber are aligned, and the lens surface on the FB side of the small circular region LR centered on the optical axis of the lens is covered with a non-reflective film. By providing a through hole in the circular area of the lens, the aperture of the optical fiber receives only reflected light from the object to be measured, eliminating noise caused by reflected light from the optical system and further improving measurement accuracy.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の一実施例の構成図、第２図は本発明の
第２実施例の構成図、第３図は非反射対策を行う領域Ｌ
Ｒの説明図、第４図は従来例の構成図、第５図は別の従
来例の構成図である。 ＴＧ・・測定対象、ＦＢ・・・投受光用光ファイバーＦ
ＢＯ・・・光源用光ファイバー、ＦＢＩ、ＦＢ２・・・
測光用光ファイバー、ＪＴ　・接続部、ＭＴ・・・モー
タ、ｃｐ・・・チョッパー、ＬＳ・・光源、Ｆｌ、Ｆ２
・・・フィルター、３１．Ｓ２・・・光センサ−、Ｃｌ
Ｃ２・・・コンデンサ、ＡＩ、Ａ２・・増幅器、ＨＭ・
・・投光規制板、Ｍ・・・光源光規制板、ＫＨ・・・光
学ヘッド部。 代理人　　弁理士　　　縣　　浩　介 第２ 図 ３ｔｇ 第４ｖＡ 第５図Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a block diagram of a second embodiment of the present invention, and Fig. 3 is a region L where anti-reflection measures are taken.
4 is a configuration diagram of a conventional example, and FIG. 5 is a configuration diagram of another conventional example. TG...Measurement target, FB...Optical fiber F for light transmission and reception
BO...Optical fiber for light source, FBI, FB2...
Optical fiber for photometry, JT, connection, MT...motor, cp...chopper, LS...light source, Fl, F2
...filter, 31. S2... optical sensor, Cl
C2...Capacitor, AI, A2...Amplifier, HM...
...Light projection regulating plate, M...Light source light regulating plate, KH...Optical head section. Agent Patent Attorney Hiroshi Agata 2nd Figure 3tg 4vA Figure 5

Claims (2)

【特許請求の範囲】[Claims] （１）測定対象に光を投光し測定対象からの反射光を受
光する光ファイバーと、光軸を中心とする一定領域の表
面を非反射膜で覆ったレンズを、上記光ファイバーと同
一光軸となるように配置し、上記光ファイバーからの光
を上記レンズにより測定対象に集光し、測定対象からの
反射光を上記レンズで上記光ファイバーに集光させるよ
うにしたことを特徴とする反射情報測定装置。(1) An optical fiber that emits light to the measurement target and receives reflected light from the measurement target, and a lens whose surface is covered with a non-reflective film in a certain area centered on the optical axis, are placed on the same optical axis as the optical fiber. A reflection information measuring device characterized in that the light from the optical fiber is focused on the measurement target using the lens, and the reflected light from the measurement target is focused on the optical fiber using the lens. . （２）測定対象に光を投光し測定対象からの反射光を受
光する光ファイバーと、光軸を中心とする小直径の光軸
と平行な貫通孔を設けたレンズを、上記光ファイバーと
同一光軸となるように配置し、上記光ファイバーからの
光を上記レンズにより測定対象に集光し、測定対象から
の反射光を上記レンズで上記光ファイバーに集光させる
ようにしたことを特徴とする反射情報測定装置。(2) An optical fiber that emits light to the measurement target and receives reflected light from the measurement target, and a lens with a small diameter through hole parallel to the optical axis centered on the optical axis, is used to connect the same optical fiber as the above optical fiber. Reflection information characterized in that the optical fiber is arranged so as to form an axis, the light from the optical fiber is focused on the measurement target by the above-mentioned lens, and the reflected light from the measurement target is focused on the optical fiber by the above-mentioned lens. measuring device.
JP19844588A 1988-08-09 1988-08-09 Measuring apparatus of reflection information Pending JPH0247539A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP19844588A JPH0247539A (en) 1988-08-09 1988-08-09 Measuring apparatus of reflection information

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP19844588A JPH0247539A (en) 1988-08-09 1988-08-09 Measuring apparatus of reflection information

Publications (1)

Publication Number Publication Date
JPH0247539A true JPH0247539A (en) 1990-02-16

Family

ID=16391211

Family Applications (1)

Application Number Title Priority Date Filing Date
JP19844588A Pending JPH0247539A (en) 1988-08-09 1988-08-09 Measuring apparatus of reflection information

Country Status (1)

Country Link
JP (1) JPH0247539A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006242891A (en) * 2005-03-07 2006-09-14 Tokyo Univ Of Agriculture & Technology Device for measuring characteristics of soil

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006242891A (en) * 2005-03-07 2006-09-14 Tokyo Univ Of Agriculture & Technology Device for measuring characteristics of soil

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