JPH07198341A - Water film measurement device - Google Patents
Water film measurement deviceInfo
- Publication number
- JPH07198341A JPH07198341A JP35328393A JP35328393A JPH07198341A JP H07198341 A JPH07198341 A JP H07198341A JP 35328393 A JP35328393 A JP 35328393A JP 35328393 A JP35328393 A JP 35328393A JP H07198341 A JPH07198341 A JP H07198341A
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- Japan
- Prior art keywords
- water film
- circuit
- scanning
- water
- distance
- 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.)
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- Investigating Or Analysing Materials By Optical Means (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は水膜測定装置に係り、特
に道路上を覆っている液体の膜（本明細書ではこれを総
称して「水膜」という）の厚さを測定する水膜測定装置
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water film measuring device, and more particularly to water for measuring the thickness of a liquid film covering the road (in the present specification, this is generically referred to as "water film"). The present invention relates to a film measuring device.
【０００２】[0002]
【従来の技術】道路上を覆っている水やその他の液体の
水膜の厚さ（水面の高さ）によっては、車両にスリップ
事故などをもたらし危険であるため、水膜を測定する測
定装置が従来より知られている（特公昭６２−７４８３
号公報）。この従来の測定装置は測定車に取り付けられ
ており、路面に対して所定角度で光を照射し、これによ
り得られる路面からの反射光を偏光フィルタを通して受
光した受光量から水膜を測定する。2. Description of the Related Art A measuring device for measuring a water film, which may cause a slip accident or the like on a vehicle, depending on the thickness of the water film (water height) of water or other liquid covering the road. Has been known for a long time (Japanese Patent Publication No. 62-7483).
Issue). This conventional measuring device is attached to a measuring vehicle, irradiates light at a predetermined angle with respect to a road surface, and measures the water film from the amount of light received by the reflected light from the road surface obtained through a polarizing filter.
【０００３】この従来の水膜測定装置によれば、水によ
る光の反射の偏光特性を利用して水に覆われた部分と水
に覆われていない部分との比率を求めるものであり、簡
単な手段により路面水面の構成割合を定量的に測定する
ことができ、スリップとの相関関係が明らかになるなど
の特長を有する。According to this conventional water film measuring apparatus, the ratio between the portion covered with water and the portion not covered with water is obtained by utilizing the polarization characteristic of the reflection of light by water. It is possible to quantitatively measure the composition ratio of road surface and water surface by various means, and it has a feature that the correlation with slip becomes clear.
【０００４】[0004]
【発明が解決しようとする課題】しかるに、上記の従来
の水膜測定装置は専用の測定車に搭載して走行しながら
測定車の真下を測定するものであり、路面の水が冠した
割合を一定区間の道路全体にわたって調査するものであ
るため、全般の路面状況の把握には役立つが、自車両の
安全確保のために水膜の厚さを測定するものではない。
また、この従来装置は自車両の真下を測定するので、水
が有ったと判断できても減速等の回避行動をとる余裕が
ない。更に、この従来装置は道路の水濡れの有無、また
はその割合を測定することはできるが、水膜の厚さを測
定することはできない。測定車などの車両にとって水膜
が危険なのはタイヤの溝等を利用して接地部分の水が排
除することができないほどに水膜が厚い場合であり、薄
い水膜が道路一面を覆っていても安全である反面、タイ
ヤの接地する部分に一定量以上の厚さの水があることは
危険であるので転舵や減速等の回避行動をとる必要があ
る。However, the above-mentioned conventional water film measuring device is mounted on a dedicated measuring vehicle to measure the position directly below the measuring vehicle while running, and the ratio of water on the road surface is measured. Since it is an investigation over the entire road in a certain section, it is useful for understanding the overall road surface condition, but it does not measure the water film thickness to ensure the safety of the own vehicle.
Further, since this conventional device measures the position directly below the host vehicle, even if it can be determined that there is water, there is no room to take avoiding actions such as deceleration. Furthermore, this conventional device can measure the presence or absence of water wetness on the road, or the ratio thereof, but cannot measure the thickness of the water film. The water film is dangerous for vehicles such as measurement cars when the water film is thick enough that the water at the ground contact part cannot be removed using the groove of the tire, etc. Even if a thin water film covers the entire road surface. On the other hand, while it is safe, it is dangerous for the portion of the tire that touches the ground to have a certain amount of water or more, so it is necessary to take avoidance actions such as steering and deceleration.
【０００５】このように、上記の従来装置では道路全般
について道路上の水の有無あるいはその割合を測定する
ことはできるが、自車両の安全を確保するために必要な
前方の水膜の厚さについて測定することはできない。As described above, the above conventional device can measure the presence or absence of water on the road or the ratio of water on the road as a whole, but the thickness of the water film in front of the vehicle required to ensure the safety of the vehicle. Can't be measured.
【０００６】本発明は以上の点に鑑みなされたもので、
車両の安全走行に大きく影響する車両前方の水膜の厚さ
を、前方を照射する光が水によって減衰された割合から
算出測定しうる水膜測定装置を提供することを目的とす
る。The present invention has been made in view of the above points,
An object of the present invention is to provide a water film measuring device capable of calculating and measuring the thickness of a water film in front of the vehicle, which greatly affects safe running of the vehicle, from the rate at which the light illuminating the front is attenuated by water.
【０００７】[0007]
【課題を解決するための手段】本発明は上記の目的を達
成するため、測定しようとする液体の膜である水膜の厚
さの程度に応じて受光信号の減衰量が変化する波長の光
ビームを前方の路面上へ出射し、これにより得られる反
射光を受光して受光信号の到達時間から目標までの距離
を求める走査型距離測定装置と、走査型距離測定装置か
らの受光信号に基づいて反射光強度を測定する反射光強
度測定回路と、反射光強度測定回路からの測定結果と、
走査型距離測定装置からの出力とに基づいて水膜による
受光レベルの減衰の割合から水膜の厚さを逆算する水膜
厚さ算出回路とを有する構成としたものである。In order to achieve the above-mentioned object, the present invention provides a light of a wavelength whose attenuation amount of a received light signal changes according to the thickness of a water film which is a film of a liquid to be measured. Based on the received light signal from the scanning distance measuring device, which emits a beam to the front road surface, receives the reflected light obtained by this, and obtains the distance from the arrival time of the received light signal to the target And a measurement result from the reflected light intensity measurement circuit, which measures the reflected light intensity,
A water film thickness calculating circuit for calculating back the thickness of the water film from the rate of attenuation of the received light level by the water film based on the output from the scanning distance measuring device.
【０００８】[0008]
【作用】本発明では、走査型距離測定装置により前方へ
所定の、すなわち水膜の厚さの程度により受光信号の適
当な減衰量を有する波長の光ビームを出射させて路面上
の水膜を通して路面で反射させ、この反射光を水膜を再
び通して走査型距離測定装置により受光して、受光信号
から反射光強度測定回路により反射光強度を測定する。
そして、水膜厚さ算出回路により水膜による受光レベル
の減衰の割合から水膜の厚さを逆算する。従って、本発
明では装置前方の水膜の厚さを測定することができる。According to the present invention, the scanning distance measuring device emits a light beam of a predetermined wavelength, that is, a wavelength having an appropriate attenuation amount of the received light signal according to the thickness of the water film, and passes through the water film on the road surface. The reflected light is reflected on the road surface, passes through the water film again, is received by the scanning distance measuring device, and the reflected light intensity is measured from the received light signal by the reflected light intensity measuring circuit.
Then, the water film thickness calculation circuit calculates the water film thickness backward from the rate of attenuation of the received light level due to the water film. Therefore, in the present invention, the thickness of the water film in front of the device can be measured.
【０００９】[0009]
【実施例】次に、本発明の実施例について説明する。図
１は本発明になる水膜測定装置の一実施例のブロック図
を示す。同図に示すように、本実施例の水膜測定装置
は、走査型距離測定装置１と反射光強度測定回路２と水
膜厚さ算出回路３とより構成されており、これらは車両
等に搭載されている。走査型距離測定装置１は前方へ光
ビームを出射する一方、反射光を受光するもので、光ビ
ームを走査することで光ビームの拡がり角を狭くできる
ため、目標に当たる光の密度を増大でき、従って、車両
に搭載されることにより、従来多く利用されているリフ
レクタからの反射のみならず、車体からの反射光も測定
できる。EXAMPLES Next, examples of the present invention will be described. FIG. 1 shows a block diagram of an embodiment of a water film measuring device according to the present invention. As shown in the figure, the water film measuring device of the present embodiment includes a scanning distance measuring device 1, a reflected light intensity measuring circuit 2 and a water film thickness calculating circuit 3, which are installed in a vehicle or the like. It is installed. The scanning distance measuring device 1 emits a light beam forward while receiving reflected light. Since the divergence angle of the light beam can be narrowed by scanning the light beam, the density of light hitting the target can be increased, Therefore, when mounted on a vehicle, not only the reflection from a reflector that has been widely used in the past but also the reflected light from the vehicle body can be measured.
【００１０】これにより、横向きの車両その他の障害物
であっても検出することが可能となる。また、当然のこ
とながら、下方を走査することにより路面からの反射光
を検出することもでき、路面上の障害物や凹凸の検出が
可能となる。As a result, it becomes possible to detect even a laterally oriented vehicle or other obstacle. Further, as a matter of course, it is possible to detect the reflected light from the road surface by scanning the lower part, and it is possible to detect the obstacle or the unevenness on the road surface.
【００１１】走査型距離測定装置１より出射される光ビ
ーム（出射光）６が仮に可視光であるものとすると、水
が汚れていない限り殆ど吸収がないので、仮に路面５が
水で覆われても一部は表面反射されて水面からの反射光
７となるものの、水を通して路面５で反射された反射光
８が入射光路を逆進するため、この路面からの反射光８
を受光することができる。しかしながら、路面５からの
反射光８は殆ど減衰しないので、この変動を利用しての
水膜の厚さの測定はできない。If the light beam (emitted light) 6 emitted from the scanning distance measuring device 1 is assumed to be visible light, there is almost no absorption unless the water is dirty, so the road surface 5 is temporarily covered with water. Even though a part of the light is reflected on the surface to become the reflected light 7 from the water surface, the reflected light 8 reflected on the road surface 5 through the water travels backward in the incident light path.
Can be received. However, since the reflected light 8 from the road surface 5 is hardly attenuated, the thickness of the water film cannot be measured by utilizing this fluctuation.
【００１２】一方、上記の光ビーム６の波長が近赤外領
域であるときには水の吸収の極めて強いラインも存在す
るが、それ以外では比較的吸収が少なく、また中赤外領
域以上では吸収が極めて強くなるという問題がある。し
かし、アイセーフ波長と呼ばれ、ＪＩＳ Ｃ６８０２に
てもパルスの場合には他の波長領域に比べて１００倍の
最大許容露光量（ＭＰＥと略される）が認められる１．
５３μｍ〜１．５５μｍの波長は、今後のレーザ距離測
定装置への利用が期待されているが、水に対しては適度
な吸収（１ｍｍ当たりの透過率約３０％）であるので、
厚さ数ｍｍの水の層を減衰を利用して測定するのにも最
適となる。従って、本実施例ではこのアイセーフ波長の
光レーザパルスを前記出射光６として用いる。On the other hand, when the wavelength of the light beam 6 is in the near-infrared region, there is also a very strong absorption line of water, but in other regions, the absorption is relatively small, and in the mid-infrared region and above, the absorption is relatively small. There is a problem of becoming extremely strong. However, it is called an eye-safe wavelength, and even in JIS C6802, in the case of a pulse, a maximum allowable exposure amount (abbreviated as MPE) that is 100 times that in other wavelength regions is recognized.
The wavelength of 53 μm to 1.55 μm is expected to be used for a laser distance measuring device in the future, but since it has an appropriate absorption for water (transmittance of about 30% per 1 mm),
It is also most suitable for measuring a water layer having a thickness of several mm using attenuation. Therefore, in this embodiment, an optical laser pulse having this eye-safe wavelength is used as the emitted light 6.
【００１３】波長が僅かに異なると透過率も変動する
が、仮に１ｍｍ当たりの透過率を３０％とした場合、路
面上に１ｍｍの厚さの水膜があると、路面からの反射光
の強さは水の無い場合の９％（往復での減衰を考えるの
で、０．３×０．３＝０．０９）となる。すなわち、水
膜の厚さが１ｍｍ増す毎に反射光量は約１／１０とな
り、路面の反射率の差異による受光量の変動に比して大
きな値であるので水膜の存在として認識でき、また概略
の厚さを算出することができる。If the wavelength is slightly different, the transmittance also fluctuates, but if the transmittance per 1 mm is 30% and there is a water film with a thickness of 1 mm on the road surface, the intensity of the reflected light from the road surface will increase. This is 9% of that without water (0.3 × 0.3 = 0.09 because attenuation in a round trip is considered). That is, each time the thickness of the water film increases by 1 mm, the amount of reflected light becomes about 1/10, which is a large value compared to the variation in the amount of light received due to the difference in the reflectance of the road surface. The approximate thickness can be calculated.
【００１４】目的は安全確認であるので、水膜の正確な
厚さを知る必要はなく、安全走行可能か否かがわかれば
良い。タイヤの種類によっては走行可能な水膜の厚さが
変わるが、波長を僅かにずらすと、透過率が変化するの
で安全走行可能な水膜の厚さに合わせた波長を選ぶこと
により、適切な判断を行えると考えられる。Since the purpose is safety confirmation, it is not necessary to know the exact thickness of the water film, and it suffices to know whether or not safe traveling is possible. The thickness of the water film that can be run changes depending on the type of tire, but if the wavelength is slightly shifted, the transmittance changes, so selecting a wavelength that matches the thickness of the water film that allows safe driving It is considered possible to make a judgment.
【００１５】図２は走査型距離測定装置１の一例の構成
図を示す。同図に示すように、走査型距離測定装置１は
ドライバ１０、レーザ光源１１、出射レンズ１２、走査
機構１３、受光レンズ１４、光検出部１５、距離算出／
２次元情報処理回路１６、アラーム送出回路１７、走査
方向認識回路１８及び表示部１９より構成されている。
レーザ光源１１は前記したアイセーフ波長の光ビームを
出射する。FIG. 2 is a block diagram showing an example of the scanning distance measuring device 1. As shown in the figure, the scanning distance measuring device 1 includes a driver 10, a laser light source 11, an emitting lens 12, a scanning mechanism 13, a light receiving lens 14, a light detecting unit 15, and a distance calculating /
It is composed of a two-dimensional information processing circuit 16, an alarm sending circuit 17, a scanning direction recognition circuit 18, and a display section 19.
The laser light source 11 emits a light beam having the above-mentioned eye-safe wavelength.
【００１６】次に、この走査型距離測定装置１の動作に
ついて説明する。ドライバ１０により駆動されたレーザ
光源１１より出射された、水に対して適当な減衰量とな
る波長の光ビームパルスは、出射レンズ１２により拡が
り角を所定の角度に制限されて図１に６で示した出射光
として出射される。走査される場合は一般に拡がり角を
小さくできる。出射光（図１の６）が走査機構１３によ
り所要方向に偏向されて目標９に当たると反射され、そ
の反射光（図１では路面からの拡散反射光８）が走査機
構１３を通り受光レンズ１４に到達し、ここで集光され
た後光検出部１５に入射される。Next, the operation of the scanning type distance measuring device 1 will be described. A light beam pulse of a wavelength emitted from a laser light source 11 driven by a driver 10 and having an appropriate attenuation amount with respect to water is limited to a predetermined divergence angle by an emission lens 12, and the divergence angle is set to 6 in FIG. It is emitted as the emitted light shown. The divergence angle can generally be reduced when scanned. The emitted light (6 in FIG. 1) is deflected in a required direction by the scanning mechanism 13 and reflected when it hits the target 9. The reflected light (diffuse reflected light 8 from the road surface in FIG. 1) passes through the scanning mechanism 13 and the light receiving lens 14 After reaching the position, the light is focused here and then is incident on the post-light detection unit 15.
【００１７】光検出部１５の主要構成品は光検出器であ
るが、その他必要に応じて視野絞りや干渉フィルタ等を
使用する場合があるが、本実施例の主目的ではないので
その説明は省略する。距離算出／２次元情報処理回路１
６は光検出部１５で受光した光の到着時間と走査方向認
識回路１８からの走査位置情報とにより、各走査方向に
対する距離を算出し、所要データをアラーム送出回路１
７に供給する。アラーム送出回路１７は距離算出／２次
元情報処理回路１６からのデータと、図１に示した水膜
厚さ算出回路３からのデータとに基づいて自車両に影響
を及ぼす障害物等がある場合にアラームを外部に送出す
る一方、表示部１８に安全の場合を含めてデータを送出
する。The main component of the photo-detecting section 15 is a photo-detector, but a field stop, an interference filter or the like may be used if necessary, but this is not the main purpose of the present embodiment, so its explanation will be omitted. Omit it. Distance calculation / 2D information processing circuit 1
Reference numeral 6 calculates the distance in each scanning direction based on the arrival time of the light received by the photodetector 15 and the scanning position information from the scanning direction recognition circuit 18, and outputs the required data to the alarm sending circuit 1
Supply to 7. When there is an obstacle or the like that affects the own vehicle based on the data from the distance calculation / two-dimensional information processing circuit 16 and the data from the water film thickness calculation circuit 3 shown in FIG. While the alarm is sent to the outside, the data is sent to the display unit 18 including the case of safety.
【００１８】また、光検出部１５により反射光を受光し
て得られた受光信号は一部が分岐されて図１に示した反
射光強度測定回路２へ出力される。また、距離算出／２
次元情報処理回路１６により得られた情報が図１に示し
た水膜厚さ算出回路３へ出力される。A part of the received light signal obtained by receiving the reflected light by the photodetector 15 is branched and output to the reflected light intensity measuring circuit 2 shown in FIG. Also, distance calculation / 2
The information obtained by the dimension information processing circuit 16 is output to the water film thickness calculation circuit 3 shown in FIG.
【００１９】再び図１に戻って説明するに、図２に示し
た構成の走査型距離測定装置１からの出射光（光レーザ
パルス）６は、通常は路面５（図２の目標９）に当たり
拡散反射光８として走査型距離測定装置１に戻ってく
る。路面５の上に水膜があると、上記の出射光６は水面
４で一部が表面反射されるが、大部分は屈折しながら水
に入射し、一部が吸収された後、路面５に当たり拡散反
射され再度水を通して吸収され、水面４で再度屈折され
た後拡散反射光８として走査型距離測定装置１に戻る。Returning to FIG. 1 again, the emitted light (optical laser pulse) 6 from the scanning distance measuring device 1 having the configuration shown in FIG. 2 normally hits the road surface 5 (target 9 in FIG. 2). The diffuse reflection light 8 returns to the scanning distance measuring device 1. If there is a water film on the road surface 5, the emitted light 6 is partly surface-reflected on the water surface 4, but most of it is refracted and incident on the water, and after part of it is absorbed, the road surface 5 Then, it is diffusely reflected, absorbed again through water, refracted again on the water surface 4, and then returned to the scanning distance measuring device 1 as diffuse reflected light 8.
【００２０】走査型距離測定装置１は前記したようにこ
の拡散反射光８を受光して受光信号に変換し、得られた
受光信号の一部を分岐して反射光強度測定回路２へ供給
する一方、受光信号の到達時間から目標までの距離を求
め、走査方向認識回路１８からの情報を基にした２次元
情報とを組み合わせる距離算出／２次元情報処理回路１
６の出力情報を水膜厚さ検出回路３へ出力する。As described above, the scanning distance measuring device 1 receives the diffuse reflected light 8 and converts it into a received light signal, and branches a part of the obtained received light signal to supply it to the reflected light intensity measuring circuit 2. On the other hand, the distance calculation / two-dimensional information processing circuit 1 in which the distance to the target is obtained from the arrival time of the received light signal and the distance is combined with the two-dimensional information based on the information from the scanning direction recognition circuit 18
The output information of 6 is output to the water film thickness detection circuit 3.
【００２１】反射光強度測定回路２は入力受光信号から
走査型距離測定装置１に入射された拡散反射光８の反射
光強度を測定し、測定結果を水膜厚さ算出回路３へ出力
する。水膜厚さ検出回路３は距離算出／２次元情報処理
回路１６の出力情報を基に水膜が無ければ得られるであ
ろう受光レベルを算出し、反射光強度測定回路２からの
反射光強度測定結果とを比較して水膜による減衰を求
め、水膜の厚さを算出する。The reflected light intensity measuring circuit 2 measures the reflected light intensity of the diffuse reflected light 8 incident on the scanning distance measuring device 1 from the input received light signal, and outputs the measurement result to the water film thickness calculating circuit 3. The water film thickness detection circuit 3 calculates the received light level that would be obtained without a water film based on the output information of the distance calculation / two-dimensional information processing circuit 16, and the reflected light intensity from the reflected light intensity measuring circuit 2 is calculated. The thickness of the water film is calculated by comparing the measurement results with the attenuation by the water film.
【００２２】ここで、路面５上の水膜の屈折率ｎ、水膜
の厚さｄ、出射光６の水膜への入射角θ、屈折角θ′、
透過率Ｔとの関係について説明する。斜め入射のため、
実際に水膜内を通過する距離は増大する。まず、屈折の
法則により次式が成立する。Here, the refractive index n of the water film on the road surface 5, the thickness d of the water film, the incident angle θ of the emitted light 6 to the water film, the refraction angle θ ',
The relationship with the transmittance T will be described. Due to the oblique incidence,
The distance actually passing through the water film increases. First, the following equation is established by the law of refraction.
【００２３】 ｓｉｎθ／ｎ＝ｓｉｎθ′ （１） また、水膜内を通過する光の距離をＬとすると、距離Ｌ
は水膜の厚さｄと屈折角θ′の間に次式の関係がある。Sin θ / n = sin θ ′ (1) If the distance of the light passing through the water film is L, the distance L
Has the following relationship between the thickness d of the water film and the refraction angle θ ′.
【００２４】 ｃｏｓθ′＝ｄ／Ｌ （２） 従って、（２）式に（１）式を代入して整理することに
より、距離Ｌは次式で表される。Cos θ ′ = d / L (2) Therefore, by substituting the equation (1) into the equation (2) and rearranging, the distance L is expressed by the following equation.
【００２５】[0025]
【数１】 １ｍｍ当たりの透過率をｔとすると、水中を距離Ｌだけ
通過したときの透過率ＴはｔのＬ乗となる。実際には水
中を往復するので２Ｌの距離で考え、透過率はｔの２Ｌ
乗となる。[Equation 1] When the transmittance per mm is t, the transmittance T when passing through the water by a distance L is t to the Lth power. Actually, it goes back and forth in water, so it is considered at a distance of 2L, and the transmittance is 2L of t.
It becomes a square.
【００２６】一例として入射角θを４５°、水膜の屈折
率ｎを１．３３、１ｍｍ当たりの透過率ｔを０．３、水
膜の厚さｄを２ｍｍとすると、（３）式より距離Ｌは
２．３６ｍｍとなる。従って、往復の距離は４．７２ｍ
ｍとなり、また、往復の透過率は０．３4.72＝３．４×
１０-3となる。同様に、水膜の厚さｄが３ｍｍのときは
往復の透過率は１．９９×１０-4となる。As an example, assuming that the incident angle θ is 45 °, the refractive index n of the water film is 1.33, the transmittance t per mm is 0.3, and the thickness d of the water film is 2 mm, then from the formula (3), The distance L is 2.36 mm. Therefore, the round trip distance is 4.72m
m, and the round-trip transmittance is 0.3 4.72 = 3.4 ×
It becomes 10 -3 . Similarly, when the thickness d of the water film is 3 mm, the reciprocal transmittance is 1.99 × 10 −4 .
【００２７】すなわち、水膜が無い場合に比して水膜が
２ｍｍあると受光レベルは３．４×１０-3倍、３ｍｍで
あると受光レベルは１．９９×１０-4倍となるので、水
膜厚さ算出回路３は距離・角度から予想される受光レベ
ルより大幅に低いレベルであった場合は減衰の割合から
水膜の厚さを逆算する。That is, when the water film is 2 mm, the light receiving level is 3.4 × 10 −3 times, and when the water film is 3 mm, the light receiving level is 1.99 × 10 −4 times as compared with the case without the water film. The water film thickness calculation circuit 3 reversely calculates the water film thickness from the attenuation rate when the received light level is significantly lower than the expected light receiving level from the distance and angle.
【００２８】このように、本実施例によれば、水膜の厚
さに応じて走査型距離測定装置１の受光レベルが顕著に
変化することを利用して、装置前方の水膜の厚さを測定
することができる。また、水膜の厚さが厚過ぎるときに
は、光ビームの波長によっては減衰が大きすぎて検知で
きないことも考えられるが、波長を僅かに変えると減衰
量は大幅に減少する（例えば、波長が１．６μｍでは１
ｍｍあたりの透過率が５０％近くになる）ので、この装
置が搭載されている車両の走行上危険となる水膜の厚さ
で適度な減衰となるような波長の光レーザを選択すれば
良い。As described above, according to this embodiment, the thickness of the water film in front of the device is utilized by utilizing the fact that the light receiving level of the scanning distance measuring device 1 remarkably changes according to the thickness of the water film. Can be measured. Further, when the water film is too thick, it may be impossible to detect because the attenuation is too large depending on the wavelength of the light beam. However, if the wavelength is slightly changed, the attenuation amount is greatly reduced (for example, when the wavelength is 1 1 at 6 μm
Since the transmittance per mm is close to 50%), it suffices to select an optical laser having a wavelength that causes appropriate attenuation with the thickness of the water film, which is dangerous when the vehicle equipped with this device is running. .
【００２９】なお、本発明は上記の実施例に限定される
ものではなく、例えば異なる角度で光を入射させ、その
ときの受光レベルの比をとる、あるいは水膜により殆ど
減衰されない波長の光を併用し、その受光レベルとの比
をとるなどにより、路面の状況による反射率等の変化を
補正するようにしてもよい。また、上記実施例では水の
膜の厚さの測定について説明したが、他の液体の膜の厚
さも同様にして測定可能である。The present invention is not limited to the above-described embodiment, and for example, the light is made incident at different angles and the ratio of the light receiving levels at that time is taken, or the light having a wavelength which is hardly attenuated by the water film is obtained. It may be used together to correct the change in reflectance and the like due to the condition of the road surface by taking a ratio with the received light level. In addition, although the thickness of the water film is measured in the above-mentioned embodiment, the thicknesses of other liquid films can be measured in the same manner.
【００３０】[0030]
【発明の効果】以上説明したように、本発明によれば、
装置前方の水膜の厚さを測定することができるため、装
置が搭載されている車両の前方の水膜が車両にとって危
険な厚さか否かをその水膜に到達する前に事前に判断し
て回避行動をとることができ、よって車両の走行の安全
性を確保することができる。また、走査型距離測定装置
内にアラーム送出回路を有することにより、障害物検出
時にアラームを送出することができるため、緊急自動停
止や回避行動をとることもできる。As described above, according to the present invention,
Since the thickness of the water film in front of the device can be measured, it is possible to determine in advance before reaching the water film whether the water film in front of the vehicle on which the device is mounted is dangerous for the vehicle. Therefore, it is possible to take avoidance action, and thus it is possible to ensure the safety of traveling of the vehicle. In addition, since the alarm transmission circuit is provided in the scanning distance measuring device, an alarm can be transmitted when an obstacle is detected, so that an emergency automatic stop or avoidance action can be taken.
【図１】本発明の一実施例のブロック図である。FIG. 1 is a block diagram of an embodiment of the present invention.
【図２】図１の走査型距離測定装置の一例の構成図であ
る。FIG. 2 is a configuration diagram of an example of the scanning distance measuring device in FIG.
１ 走査型距離測定装置 ２ 反射光強度測定回路 ３ 水膜厚さ算出回路 ４ 水面 ５ 路面 １０ ドライバ １１ レーザ光源 １２ 出射レンズ １３ 走査機構 １４ 受光レンズ １５ 光検出部 １６ 距離算出／２次元情報処理回路 １７ アラーム検出回路 １８ 走査方向認識回路 １９ 表示部 1 Scanning Distance Measuring Device 2 Reflected Light Intensity Measuring Circuit 3 Water Film Thickness Calculation Circuit 4 Water Surface 5 Road Surface 10 Driver 11 Laser Light Source 12 Emitting Lens 13 Scanning Mechanism 14 Light Receiving Lens 15 Light Detection Section 16 Distance Calculation / Two-Dimensional Information Processing Circuit 17 Alarm Detection Circuit 18 Scanning Direction Recognition Circuit 19 Display
Claims (3)
厚さの程度に応じて受光信号の減衰量が変化する波長の
光ビームを前方の路面上へ出射し、これにより得られる
反射光を受光して受光信号の到達時間から目標までの距
離を求める走査型距離測定装置と、 該走査型距離測定装置からの受光信号に基づいて反射光
強度を測定する反射光強度測定回路と、 該反射光強度測定回路からの測定結果と、前記走査型距
離測定装置からの出力とに基づいて水膜による受光レベ
ルの減衰の割合から水膜の厚さを逆算する水膜厚さ算出
回路とを有することを特徴とする水膜測定装置。1. A light beam having a wavelength at which the amount of attenuation of a received light signal changes according to the thickness of a water film, which is a film of a liquid to be measured, is emitted to the road surface ahead, and the reflection obtained thereby is obtained. A scanning distance measuring device that receives light and obtains the distance from the arrival time of the received light signal to the target, and a reflected light intensity measuring circuit that measures reflected light intensity based on the received light signal from the scanning distance measuring device, A water film thickness calculating circuit for back-calculating the thickness of the water film from the rate of attenuation of the received light level due to the water film based on the measurement result from the reflected light intensity measuring circuit and the output from the scanning distance measuring device. A water film measuring device comprising:
ムを出射するレーザ光源と、該レーザ光源からの光ビー
ムを前方の目標へ走査しつつ出射する走査機構と、該走
査機構の走査方向を検出する走査方向認識回路と、反射
光を該走査機構を通して受光する光検出器と、該光検出
器の出力受光信号により走査方向に対する距離を算出す
ると共に、前記走査方向認識回路からの情報を基にした
２次元情報を出力する距離算出／２次元情報処理回路と
を少なくとも具備することを特徴とする請求項１記載の
水膜測定回路。2. The scanning distance measuring device comprises a laser light source that emits the light beam, a scanning mechanism that emits the light beam from the laser light source while scanning the target ahead, and a scanning direction of the scanning mechanism. A scanning direction recognizing circuit, a photodetector for receiving reflected light through the scanning mechanism, and a distance with respect to the scanning direction based on an output light receiving signal of the photodetector, and information from the scanning direction recognizing circuit is calculated. 2. The water film measuring circuit according to claim 1, further comprising at least a distance calculation / two-dimensional information processing circuit that outputs two-dimensional information based on the distance.
さ算出回路により算出された水膜の厚さと、前記距離算
出／２次元情報処理回路の出力情報とに基づいて、装置
前方の障害物を検出してアラームを送出するアラーム送
出回路を更に有することを特徴とする請求項２記載の水
膜測定装置。3. The scanning distance measuring device, based on the water film thickness calculated by the water film thickness calculating circuit and the output information of the distance calculating / 2D information processing circuit, The water film measuring device according to claim 2, further comprising an alarm sending circuit that detects an obstacle and sends an alarm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5353283A JP2570613B2 (en) | 1993-12-28 | 1993-12-28 | Water film measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5353283A JP2570613B2 (en) | 1993-12-28 | 1993-12-28 | Water film measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07198341A true JPH07198341A (en) | 1995-08-01 |
| JP2570613B2 JP2570613B2 (en) | 1997-01-08 |
Family
ID=18429792
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5353283A Expired - Fee Related JP2570613B2 (en) | 1993-12-28 | 1993-12-28 | Water film measuring device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2570613B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09210905A (en) * | 1996-02-06 | 1997-08-15 | Ishikawajima Harima Heavy Ind Co Ltd | Sensing device for road surface moistness with laser |
| JP2002257934A (en) * | 2001-02-27 | 2002-09-11 | Omron Corp | Road surface condition detector for vehicle and range- finder for vehicle |
| JP2008185563A (en) * | 2007-01-31 | 2008-08-14 | Denso Corp | Measuring device, vehicle control device, and alarm device |
| CN109798835A (en) * | 2019-02-20 | 2019-05-24 | 同济大学 | Asphalt pavement surface water film thickness single-point monitoring device and installation method |
| CN112146584A (en) * | 2020-09-24 | 2020-12-29 | 重庆光年感知科技有限公司 | Laser detection algorithm for accurately measuring thickness of pavement water film |
-
1993
- 1993-12-28 JP JP5353283A patent/JP2570613B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09210905A (en) * | 1996-02-06 | 1997-08-15 | Ishikawajima Harima Heavy Ind Co Ltd | Sensing device for road surface moistness with laser |
| JP2002257934A (en) * | 2001-02-27 | 2002-09-11 | Omron Corp | Road surface condition detector for vehicle and range- finder for vehicle |
| JP2008185563A (en) * | 2007-01-31 | 2008-08-14 | Denso Corp | Measuring device, vehicle control device, and alarm device |
| CN109798835A (en) * | 2019-02-20 | 2019-05-24 | 同济大学 | Asphalt pavement surface water film thickness single-point monitoring device and installation method |
| CN112146584A (en) * | 2020-09-24 | 2020-12-29 | 重庆光年感知科技有限公司 | Laser detection algorithm for accurately measuring thickness of pavement water film |
| CN112146584B (en) * | 2020-09-24 | 2022-07-01 | 重庆光年感知科技有限公司 | Laser detection algorithm for accurately measuring thickness of pavement water film |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2570613B2 (en) | 1997-01-08 |
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