JP3146838B2 - Distance sensor head - Google Patents
Distance sensor headInfo
- Publication number
- JP3146838B2 JP3146838B2 JP07471294A JP7471294A JP3146838B2 JP 3146838 B2 JP3146838 B2 JP 3146838B2 JP 07471294 A JP07471294 A JP 07471294A JP 7471294 A JP7471294 A JP 7471294A JP 3146838 B2 JP3146838 B2 JP 3146838B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- vehicle
- distance
- signal
- sensor head
- 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.)
- Expired - Fee Related
Links
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- Optical Radar Systems And Details Thereof (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は、車両用の測距センサー
ヘッドに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring sensor head for a vehicle.
【0002】[0002]
【従来の技術】従来の車両用の測距センサーヘッドを用
いた車両間距離測定の一例として、図6に示す方式によ
るものがある。この方式は、図6で先行車両65の後部
に向けてLED光を送光する測距センサーヘッド61を
車両60に設け、先行車両65の後部のリフレクター6
6で反射したLED光を測距センサーヘッド61で受光
し(図6(a))、送光から受光までの時間を測定して
既知であるLED光の速度から先行車両との距離をR=
C×ΔT/2として算出する(図6(b))。ここで、
CはLED光の速度(光速)、ΔTはLED光の往復時
間である。2. Description of the Related Art As an example of conventional inter-vehicle distance measurement using a conventional vehicle ranging sensor head, there is a method shown in FIG. In this system, a distance measuring sensor head 61 for transmitting LED light toward the rear of the preceding vehicle 65 in FIG.
The LED light reflected at 6 is received by the distance measuring sensor head 61 (FIG. 6A), the time from light transmission to light reception is measured, and the distance to the preceding vehicle is calculated from the known speed of the LED light as R =
It is calculated as C × ΔT / 2 (FIG. 6B). here,
C is the speed (light speed) of the LED light, and ΔT is the round trip time of the LED light.
【0003】上述の測距センサーヘッドの構造として
は、例えば、図7に示すものがある。As a structure of the above-described distance measuring sensor head, for example, there is one shown in FIG.
【0004】CPU71でLD駆動回路72を制御し、
レーザダイオードLD1,LD2,LD3を順次切換え
て駆動させLED光を発光させる。[0004] The CPU 71 controls the LD drive circuit 72,
The laser diodes LD1, LD2, and LD3 are sequentially switched and driven to emit LED light.
【0005】LED光は、送光レンズ73で集光されて
測距センサーヘッド70の前面の透明カバー74を透過
して先行車両のリフレクターに達する。先行車両のリフ
レクターで反射されたLED光は測距センサーヘッド7
0に戻り、前面の透明カバー74を再び透過して受光レ
ンズ75で受光素子としてのフォトダイオードPD1,
PD2に入光し反射光信号として出力される。反射光信
号は増幅器76で増幅されCPU71に送出され、CP
U71では送光から受光までの時間を基に既知であるL
ED光の速度から先行車両との距離を上述した車間距離
算出式より計算する。The LED light is condensed by the light transmitting lens 73, passes through the transparent cover 74 on the front of the distance measuring sensor head 70, and reaches the reflector of the preceding vehicle. The LED light reflected by the reflector of the preceding vehicle is transmitted to the ranging sensor head 7.
0, the light passes through the front transparent cover 74 again, and is received by the light receiving lens 75 at the photodiode PD1 as a light receiving element.
The light enters the PD 2 and is output as a reflected light signal. The reflected light signal is amplified by the amplifier 76 and sent to the CPU 71, where
In U71, L which is known based on the time from light transmission to light reception
The distance to the preceding vehicle is calculated from the speed of the ED light using the above formula for calculating the following distance.
【0006】また、LED光が透過する透明カバー74
の汚れを検出するために測距センサーヘッド70には測
距するための送受光用の素子とは別に、微弱な出力の発
光素子LED(発光ダイオード)と受光素子フォトダイ
オードPDを設け、発光素子LEDからの光を送光し、
受光素子フォトダイオードPDで受光した透明カバー7
4による反射光を反射光信号とし、増幅器76で増幅し
てCPU71に送出する。CPU71では入力した反射
光信号から透明カバー74の汚れ16の存在を判別する
と共に、この判別結果に応じて増幅器76の増幅度合を
変化させている。A transparent cover 74 through which LED light passes.
The distance measuring sensor head 70 is provided with a light emitting element LED (light emitting diode) and a light receiving element photodiode PD having a weak output in addition to a light transmitting / receiving element for measuring a distance in order to detect contamination of the light emitting element. Send the light from the LED,
Transparent cover 7 received by photodiode PD
The light reflected by 4 is converted into a reflected light signal, amplified by an amplifier 76, and transmitted to the CPU 71. The CPU 71 determines the presence of the dirt 16 on the transparent cover 74 from the input reflected light signal, and changes the amplification degree of the amplifier 76 according to the determination result.
【0007】[0007]
【発明が解決しようとする課題】上述したような従来の
測距センサーヘッドにあっては、透明カバー74の汚れ
を検出するために測距用の発光素子PD1,PD2,P
D3のみを用いるとその出力が高いため、極めて近距離
にある透明カバー74の面からの反射光の受光について
みると、透明カバー74の面が汚れている場合も汚れて
いない場合も受光強度が非常に大きく、受光レベルの差
が僅かであるために透明カバー面74が汚れているか汚
れていないかの判定ができないこととなる。In the conventional distance measuring sensor head as described above, the light emitting elements PD1, PD2, P2 for distance measurement are used to detect dirt on the transparent cover 74.
When only D3 is used, the output is high. Therefore, regarding the reception of reflected light from the surface of the transparent cover 74 at a very short distance, the received light intensity is high both when the surface of the transparent cover 74 is dirty and when it is not dirty. Since the difference between the light receiving levels is very large and the transparent cover surface 74 is dirty, it cannot be determined whether or not the transparent cover surface 74 is dirty.
【0008】そこで、遠距離の測距を可能にするために
高出力の発光素子PD1,PD2,PD3をもつLED
送光部とは別にLED光が透過する透明カバー74の汚
れを検出するために測距用の発光素子の出す波長とは異
なる波長で、微弱な出力の発光素子LEDを有する送光
部と透明カバー74の汚れに反射した微弱なLED光を
受光する受光部を設けている。[0008] Therefore, an LED having light emitting elements PD1, PD2 and PD3 of high output in order to enable long distance measurement.
In order to detect dirt on the transparent cover 74 through which LED light is transmitted separately from the light transmitting unit, a light transmitting unit having a light emitting element LED with a weak output at a wavelength different from the wavelength emitted by the light emitting element for distance measurement is used. A light receiving unit that receives the weak LED light reflected by the dirt on the cover 74 is provided.
【0009】このため、距離測距センサーヘッドの容積
が大きくなること、及び部品数が多いという問題点があ
った。For this reason, there has been a problem that the volume of the distance measuring sensor head is increased and the number of parts is large.
【0010】本発明はこのような従来の問題点に着目し
てなされたものであり、車間距離測定用として設けた送
光部及び受光部の他に、透明カバーの汚れ検出用に送光
部及び受光部を設けなくても済む構成とした測距センサ
ーヘッドを提供することを目的とする。The present invention has been made in view of such a conventional problem. In addition to a light transmitting unit and a light receiving unit provided for measuring a distance between vehicles, a light transmitting unit for detecting dirt on a transparent cover is provided. It is another object of the present invention to provide a distance measuring sensor head which does not need to be provided with a light receiving section.
【0011】[0011]
【課題を解決するための手段】上記の目的を達成するた
めに、請求項1に記載の発明の測距センサーヘッドは、
図1に示す如く、車両前方へ光を出射する複数の発光素
子A1 〜An を有する発光部Aと、この発光部Aの複数
の発光素子A1 〜An のうち少なくとも1つの発光素子
を所定タイミング毎に発光させる駆動手段Eと、この発
光部Aによる出射光を車両前方の外部へ透過させる一
方、前記出射光に基づく車両前方の外部からの到来光を
車両後方へ透過させる透過部Bと、前記発光部Aの複数
の発光素子A1 〜An のうち少くとも1つの発光素子の
出射光による前記透過部Bでの反射光及び前記到来光を
受光する受光素子Cと、前記発光部Aの発光素子A1 〜
An が1回の出射光を出射してから前記受光素子が到来
光を受光するまでの往復時間に基づき自車両と自車両前
方の先行移動体との間の距離を算出する距離算出手段D
と、前記発光部Aの発光素子が前記1回の出射光を出射
した際に、前記透過部Bでの反射光を前記受光素子で受
光した受光レベルに基づいて前記透過部Bの汚れを判断
する汚れ判断手段Fと、を有することを特徴とする。上
記の目的を達成するために、請求項2に記載の発明は、
請求項1記載の発明の測距センサーヘッドにおいて、前
記距離算出手段Dは、前記受光素子Cが受光したアナロ
グ信号を所定周波数のサンプリングパルス毎に所定基準
レベルと比較し、前記アナログ信号が前記所定基準レベ
ルを超えるときを“1”、前記アナログ信号が前記所定
基準レベル以下のときを“0”に対応させてデジタル信
号に変換するサンプリング手段と、前記サンプリング手
段により変換された前記デジタル信号を前記サンプリン
グパルス毎に所定送信回数だけ加算した加算値を算出す
る加算手段とを有し、前記加算値が最大値を示したサン
プリングパルスを前記先行移動体からの反射信号と見な
して前記先行移動体との距離を算出することを特徴とす
る。 In order to achieve the above object, a distance measuring sensor head according to the first aspect of the present invention comprises:
As shown in FIG. 1, a light emitting unit A having a plurality of light emitting elements A1 to An for emitting light forward of a vehicle, and a plurality of light emitting units A
At least one of the light emitting elements A1 to An
A driving means E that emits light at predetermined timings, and a transmitting unit that transmits light emitted from the light emitting unit A to the outside in front of the vehicle and transmits incoming light from the outside in front of the vehicle based on the emitted light to the rear of the vehicle. B, a light-receiving element C for receiving the reflected light and the arriving light at the transmission section B due to the light emitted from at least one of the plurality of light-emitting elements A1 to An of the light-emitting section A; A light-emitting elements A1 to A
A distance for calculating the distance between the host vehicle and the preceding moving body in front of the host vehicle based on the round trip time from when An emits one outgoing light to when the light receiving element receives the incoming light. Calculation means D
And the light emitting element of the light emitting unit A emits the one outgoing light
And a dirt determining means F for determining dirt on the transmissive part B based on a light receiving level of the light reflected by the transmissive part B received by the light receiving element. In order to achieve the above object, the invention described in claim 2 is
2. The distance measuring sensor head according to claim 1, wherein the distance calculating means D compares an analog signal received by the light receiving element C with a predetermined reference level for each sampling pulse of a predetermined frequency, and Sampling means for converting the digital signal into a digital signal corresponding to "1" when the reference level is exceeded and "0" when the analog signal is equal to or less than the predetermined reference level; Adding means for calculating an added value obtained by adding a predetermined number of times of transmission for each sampling pulse, and the preceding moving object is regarded as a reflection signal from the preceding moving object with the sampling pulse indicating the maximum value as the added value. Is calculated .
【0012】[0012]
【作用】請求項1記載の発明による測距センサーヘッド
であれば、駆動手段Eにより発光部Aの複数の発光素子
A1 〜An のうち少なくとも1つの発光素子を所定タイ
ミング毎に発光させるため、この発光素子での出射光に
基づく車両前方の外部からの到来光を透過部Bを通して
受光素子Cが受光して得られるこの受光素子Cでの1回
の出射光を出射してから反射光を受光するまでの往復時
間に基づき、距離算出手段Dにより自車両と自車両前方
の先行移動体との間の距離を算出することができる。ま
た、発光部Aの発光素子がこの1回の出射光を出射した
際に、受光素子Cで受光した反射光の受光レベルに基づ
いて透過部Bの汚れを汚れ判断手段Fにて判断すること
ができる。請求項2記載の発明による測距センサーヘッ
ドによれば、受光素子Cが受光したアナログ信号を所定
周波数のサンプリングパルス毎にデジタル信号に変換
し、このデジタル信号をサンプリングパルス毎に所定送
信回数だけ加算し、加算値が最大となったところが先行
移動体からの反射信号であると判断することにより、受
光信号を反射光信号とノイズとに分離することが可能と
なる。 In the distance measuring sensor head according to the first aspect of the present invention , the plurality of light emitting elements of the light emitting section A are driven by the driving means E.
At least one of the light-emitting elements A1 to An
In order to emit light every time the light receiving element C receives the light coming from outside in front of the vehicle based on the light emitted from the light emitting element through the transmitting portion B, the light receiving element C obtains the light once.
The distance calculating means D can calculate the distance between the host vehicle and the preceding moving body ahead of the host vehicle based on the round trip time from when the emitted light is emitted to when the reflected light is received. In addition, the light emitting element of the light emitting section A emitted this one outgoing light.
At this time, the stain on the transmitting portion B can be determined by the stain determining means F based on the light receiving level of the reflected light received by the light receiving element C. According to the distance measuring sensor head according to the second aspect of the invention, the analog signal received by the light receiving element C is converted into a digital signal for each sampling pulse of a predetermined frequency, and this digital signal is added a predetermined number of times of transmission for each sampling pulse. However, by judging that the position where the added value becomes the maximum is the reflected signal from the preceding moving body, it is possible to separate the received light signal into the reflected light signal and the noise .
【0013】[0013]
【実施例】図2は本発明に基づく測距センサーヘッドの
一実施例の構成を示すブロック図であり、1はCPU
(制御・演算部)、2は送光駆動回路、3は複数の発光
素子(例えばLED)からなる発光部、4は送光レン
ズ、5は測距センサーヘッドの透過部としての透明カバ
ー、6は先行車両による反射波、7はガラス面の汚れに
よる反射光、8は距離データ出力部、9は受光フィル
タ、10は受光レンズ、11は受光素子(フォトダイオ
ード)からなる受光部、12は増幅器、13は信号処理
部、14はサンプリング回路、15は加算回路、16は
ガラス面に付着した汚れ、100は車両用の測距センサ
ーヘッドである。FIG. 2 is a block diagram showing the configuration of an embodiment of a distance measuring sensor head according to the present invention.
(Control / arithmetic unit) 2 is a light transmitting drive circuit, 3 is a light emitting unit composed of a plurality of light emitting elements (for example, LEDs), 4 is a light transmitting lens, 5 is a transparent cover as a transmitting unit of a distance measuring sensor head, 6 Is a reflected wave from a preceding vehicle, 7 is reflected light due to dirt on a glass surface, 8 is a distance data output unit, 9 is a light receiving filter, 10 is a light receiving lens, 11 is a light receiving unit including a light receiving element (photodiode), and 12 is an amplifier. , 13 is a signal processing unit, 14 is a sampling circuit, 15 is an addition circuit, 16 is dirt attached to a glass surface, and 100 is a distance measuring sensor head for a vehicle.
【0014】なお、図2で、透過部として前面ガラス5
が用いられているが、ガラスに限ることなくLED光等
の電磁波を透過する透明な物質から構成されたカバー状
のものであればよい。In FIG. 2, the front glass 5 is used as a transmission part.
Is used, but may be any cover material made of a transparent material that transmits electromagnetic waves such as LED light without being limited to glass.
【0015】図3は、本発明の測距センサーヘッドの基
本的動作を示すフローチャートである。FIG. 3 is a flowchart showing the basic operation of the distance measuring sensor head according to the present invention.
【0016】ステップS1で、CPU1は送光駆動回路
2を制御し複数の発光素子3の全てを順次駆動させ出力
レベルの低いLEDによる(以下LEDと称す)光を発
生させ、そのLED光を送光レンズ4で集光してビーム
状とし測距センサーヘッドの前面ガラス5を透過させて
ヘッド外に送光する。[0016] In step S1, CPU 1 is (hereinafter referred to as LED) are sequentially driven so due to a low output level LED all of the plurality of light emitting elements 3 controls the light-sending driving circuit 2 emitting light
Then , the LED light is condensed by the light transmitting lens 4 to form a beam and transmitted through the front glass 5 of the distance measuring sensor head to be transmitted outside the head.
【0017】ステップ2で、前面ガラス5のガラス面で
の反射光及び対象車両からの反射光はいずれも受光素子
11に入力し反射光信号(アナログ信号)に変換される
が、出力が微弱なので増幅器12で増幅してからCPU
1に与えられる。In step 2, both the reflected light from the glass surface of the front glass 5 and the reflected light from the target vehicle enter the light receiving element 11 and are converted into a reflected light signal (analog signal). CPU after amplification by amplifier 12
Given to one.
【0018】ステップS3では、CPU1はガラス面か
らの反射光と対象車両からの反射光の判別をLED光の
出力タイミングごとの受光レベルの比較により行い、ガ
ラス面からの反射光の場合はステップS4に移行し、対
象車両からの反射光の場合はステップS5に移行する。In step S3, the CPU 1 discriminates the reflected light from the glass surface and the reflected light from the target vehicle by comparing the light receiving level at each output timing of the LED light. The process proceeds to step S5 in the case of reflected light from the target vehicle.
【0019】ここで、図4は送光LED光及び受光信号
の波形図であり、図4(a)は送光LED出力の波形を
示し、図4(b)はガラスに汚れのない場合の受光信号
の波形を示し、図4(c)はガラスに汚れのある場合の
受光信号の波形を示す。また、図4(b),(c)でA
区間はガラス面からの反射光による反射光信号ピークで
あり、B区間は対象車両からの反射光信号とノイズの混
在した受光信号区間である。Here, FIG. 4 is a waveform diagram of the light transmitting LED light and the light receiving signal, FIG. 4 (a) shows the waveform of the light transmitting LED output, and FIG. 4 (b) shows the case where the glass is clean. FIG. 4C shows the waveform of the light receiving signal when the glass is dirty. 4 (b) and 4 (c).
The section is a reflected light signal peak due to the reflected light from the glass surface, and the B section is a light receiving signal section in which the reflected light signal from the target vehicle and the noise are mixed.
【0020】測距のために送光する微弱なLED光は図
4(a)に示すように一定の周期で送光され、受光素子
11で受光され反射光信号となるが、周期の始めに図4
(b),(c)のA区間に示すようにガラス面からの反
射光による反射光信号のピーク41があり、対象車両か
らの反射光による受光信号がそのあとに続く。このよう
にLED光の出力のタイミングよりピークを検出するこ
とでガラス面からの反射光と対象車両からの反射光の判
別ができる。The weak LED light transmitted for distance measurement is transmitted at a constant period as shown in FIG. 4A, and is received by the light receiving element 11 to become a reflected light signal. FIG.
As shown in section A of (b) and (c), there is a peak 41 of the reflected light signal due to the reflected light from the glass surface, followed by a received light signal due to the reflected light from the target vehicle. As described above, by detecting the peak from the output timing of the LED light, it is possible to determine the reflected light from the glass surface and the reflected light from the target vehicle.
【0021】ステップ4で、CPU1はガラス面の汚れ
の判定を行い、汚れが基準値を超えている場合にはステ
ップS6に移行し、汚れていないか、汚れが基準値内の
場合にはステップS5に移行する。In step 4, the CPU 1 determines whether or not the glass surface is dirty. If the dirt exceeds the reference value, the process proceeds to step S6. If the dirt is not dirty or the dirt is within the reference value, the process proceeds to step S6. Move to S5.
【0022】ガラス面の汚れの判定において、送光され
るLED光は出力レベルが低いために図4に示すように
極く距離の短いガラス面からの反射光による反射光信号
のピークの強度の方が(汚れのあるなしに拘らず)距離
の遠い対象車両からの反射光による反射光信号の強度よ
りも大きくなる。これにより、CPU1は増幅器12で
変換されたアナログ信号のレベルがガラス面の汚れの基
準値を超えるか否を検出し判定することができる(詳細
は後述(<1.汚れの判定>参照))。In the determination of the dirt on the glass surface, the transmitted LED light has a low output level, and as shown in FIG. 4, the intensity of the peak of the reflected light signal due to the reflected light from the very short glass surface is reduced. In this case, the intensity of the reflected light signal due to the reflected light from the target vehicle at a long distance (whether dirty or not) is larger. Thus, the CPU 1 can detect and determine whether or not the level of the analog signal converted by the amplifier 12 exceeds the reference value of the stain on the glass surface (for details, see (<1. Determination of stain>)). .
【0023】ステップS5では、CPU1は先行車両後
部のリフレクターで反射した反射光による受光信号(反
射光信号+ノイズ)から反射光信号基準値を基に反射光
信号を判別して車間距離計算を行う(詳細は後述(<
3.車間距離計算>参照))。なお、反射光信号基準値
レベルは、予め、ノイズだけの場合のアナログ信号の変
動幅から中央値として求めておくことができる。In step S5, the CPU 1 determines the reflected light signal based on the reflected light signal reference value based on the received light signal (reflected light signal + noise) reflected by the reflector at the rear part of the preceding vehicle and calculates the following distance. (See below for details (<
3. Calculation of distance between vehicles>))). Note that the reflected light signal reference value level can be obtained in advance as a median value from the fluctuation width of the analog signal in the case of only noise.
【0024】ステップS6では、前面ガラス5の汚れが
限度(汚れの基準値)を超えているので、前面ガラス5
の汚れがひどく距離算出可能な受光強度が確保できない
場合として、例えば、”ガラスの汚れにより距離測定不
可能”のような測距不能表示を行って、前面ガラスの清
掃の必要性をユーザに報知することができる(汚れの基
準値については、後述<2.汚れ限度の判定>参照)。In step S6, since the dirt on the front glass 5 exceeds the limit (standard value of dirt),
As if the dirt is badly distance calculated out possible light intensity can not be ensured, for example, "the dirt glass distance measurement impossible" performed unmeasurable display, such as, the user needs to clean the front glass A notification can be made (for the reference value of dirt, see <2. Determination of dirt limit> below).
【0025】<1.汚れの検出>発光素子3から出て送
光レンズ4を透過したLED光はセンサーヘッドの前面
ガラス5に到達する。<1. Detection of dirt> The LED light exiting from the light emitting element 3 and passing through the light transmitting lens 4 reaches the front glass 5 of the sensor head.
【0026】このとき、ガラス表面に汚れ16が付着し
ていなければLED光は前面ガラス5を透過してセンサ
ーヘッド外側に送光される。At this time, if the dirt 16 does not adhere to the glass surface, the LED light is transmitted through the front glass 5 and transmitted to the outside of the sensor head.
【0027】一方、前面ガラス5に泥等の汚れ16が付
着している場合にはLED光は前面ガラス5の汚れが付
着した部分のガラス面で反射する。そしてその反射LE
D光は受光素子11としてのフォトダイオードに入光
し、増幅器12によって反射光信号として検知される。On the other hand, when dirt 16 such as mud is attached to the front glass 5, the LED light is reflected on the glass surface of the portion of the front glass 5 where the dirt is attached. And the reflection LE
The D light enters a photodiode as the light receiving element 11 and is detected by the amplifier 12 as a reflected light signal.
【0028】反射光の量は前面ガラス5の汚れている部
分の面積によって異なるので、受光素子11としてのフ
ォトダイオードに入光する受光強度が、汚れている部分
の面積によって異なることとなり、汚れの程度を検出す
ることができる。Since the amount of reflected light varies depending on the area of the dirty portion of the front glass 5, the light receiving intensity entering the photodiode as the light receiving element 11 varies depending on the area of the dirty portion. The degree can be detected.
【0029】前面ガラス5の表面に汚れの付着がない場
合はLED光の殆どが前面ガラス5を透過していくた
め、ガラス表面からの反射光の強度は弱く、受光素子
(フォトダイオード)11を介して増幅器12により変
換されたアナログ信号レベルは図4(b)のA区間(汚
れ反射信号部分)に示すように汚れ判断の基準値以下に
なっている。When there is no dirt on the surface of the front glass 5, most of the LED light passes through the front glass 5, so that the intensity of the reflected light from the glass surface is weak, and the light receiving element (photodiode) 11 The level of the analog signal converted by the amplifier 12 via the amplifier 12 is equal to or less than a reference value for determining dirt as shown in a section A (dirt reflected signal portion) of FIG.
【0030】一方、ガラスの表面に汚れが付着している
場合は汚れの付着した部分のガラス表面からの反射によ
り受光素子11を介して増幅器12で変換したアナログ
信号レベルは図4(c)のA区間に示すように汚れ判断
の基準値を超える。On the other hand, when the surface of the glass is contaminated, the analog signal level converted by the amplifier 12 through the light receiving element 11 by the reflection of the contaminated portion from the glass surface is shown in FIG. As shown in section A, the value exceeds the reference value for dirt determination.
【0031】<2.汚れ限度の判定> ここで、前面ガラス5の汚れの実用上の限界の基準とし
て、発光素子3から送出したLED光が前面ガラス5の
汚れの付着したガラス部分を透過して測距対象物として
の先行車両のリフレクターに反射して戻った反射光の強
度が、信号処理部13で信号とノイズを識別することが
できCPU1で距離算出可能となる、最低レベルの光の
強度で検出した前面ガラス5の汚れの程度、言換えれ
ば、フォトダイオード(受光素子11)に入力する上記
反射光の強度を用いることができる。このような基準を
用いることにより、前面ガラス5の汚れがひどく距離算
出可能な受光強度が確保できない場合を検知できる。<2. Here the determination of the contamination limit>, as the basis for practical limit dirt on the front glass 5, LED light transmitted from the light-emitting element 3 is transmitted through the dirt glass portion adhered to the front glass 5 measuring object before intensity of the reflected light reflected back to the reflector of the preceding vehicle as it becomes the distance can be calculated by CPU1 can identify the signal and the noise in the signal processing unit 13, detected by the intensity of the lowest level of light The degree of dirt on the face glass 5, in other words, the intensity of the reflected light input to the photodiode (light receiving element 11) can be used. By using such a criterion, the dirt on the front glass 5 can be extremely disturbed.
It is possible to detect a case where the available light receiving intensity cannot be secured.
【0032】<3.車間距離測定>車間距離は前述した
ように、発光素子3からLED光を送光して受光素子1
1が先行車両のリフレクターの反射光を受光するまでの
時間、すなわち、反射物体までのLED光の往復時間を
計測して車間距離を求める。<3. Inter-vehicle distance measurement> As described above, the inter-vehicle distance is determined by transmitting the LED light from the light emitting element 3 to the light receiving element 1
The inter-vehicle distance is determined by measuring the time until 1 receives the reflected light of the reflector of the preceding vehicle, that is, the round trip time of the LED light to the reflecting object.
【0033】ここで、反射光信号とノイズが混在する図
4のB区間のアナログ信号に対しては、前述したように
増幅器12で変換し、更に、信号処理部13でサンプリ
ング処理及び加算処理し、加算処理の結果からCPU1
が反射光信号とノイズとを判別し、判別された反射光信
号を基に対象物までの距離を算出する。Here, the analog signal in the section B in FIG. 4 in which the reflected light signal and the noise are mixed is converted by the amplifier 12 as described above, and further the signal processing unit 13 samples the signal.
And packaging processing and addition processing, CPU 1 from the result of the addition process
Determines the reflected light signal and noise, and calculates the distance to the object based on the determined reflected light signal.
【0034】なお、送光するLED光は微弱なため受光
素子11で受光される対象車両からの反射光も微弱とな
り、そのままではノイズとの判別が困難となるため受光
した反射光信号とノイズが混在しているアナログ信号を
増幅器12で増幅して信号処理部13に入力して反射光
信号とノイズとの識別を行う。Since the transmitted LED light is weak, the reflected light from the target vehicle received by the light receiving element 11 is also weak, and it is difficult to determine the noise as it is. The mixed analog signal is amplified by the amplifier 12 and input to the signal processing unit 13 to distinguish between the reflected light signal and noise.
【0035】図5は反射光信号とノイズとの識別処理の
説明図であり、信号処理部13は図5(a)に示すよう
なアナログ信号(反射光信号+ノイズ)を、サンプリン
グ回路14で所定周波数のサンプリングパルス毎に基準
レベルに対するアナログ信号レベルを比較し、アナログ
信号レベルが基準レベルを超えるときを”1”、アナロ
グ信号レベルが基準レベル以下のときを”0”に対応さ
せて図5(b)に示すようにビット値で表し、デジタル
データに変換する。FIG. 5 is an explanatory diagram of the process of discriminating between the reflected light signal and the noise. The signal processing unit 13 converts the analog signal (reflected light signal + noise) shown in FIG. An analog signal level with respect to a reference level is compared for each sampling pulse of a predetermined frequency, and when the analog signal level exceeds the reference level, it corresponds to “1”, and when the analog signal level is less than the reference level, it corresponds to “0”. It is represented by a bit value as shown in FIG.
【0036】次に、上記により送受光のたびに得るサン
プリングパルス毎のビット値を図5(c)に示すように
連続して加算回路15で、対応ビット毎に所定送受光回
数だけ加算する。Next, as shown in FIG. 5C, the bit value for each sampling pulse obtained each time the light is transmitted and received is added by the adder 15 continuously for a predetermined number of times for each corresponding bit.
【0037】図5(c)は1回目の送受光で得たサンプ
リングパルス毎のビット値,2回目の送受光で得たサン
プリングパルス毎のビット値,・・・,5000回の送
受光で得たサンプリングパルス毎のビット値の加算プロ
セスを示し、図2(d)はその加算値をグラフ化して示
したものであり、対象物からの反射光信号が存在するビ
ットの加算値が最も大きな値となる。[0037] FIG. 5 (c) first bit value of each sampling pulse obtained by transmission and reception light, a second bit value of each sampling pulse obtained by transmitting and receiving light, ..., obtained in 5000 the beam transmitting and receiving FIG. 2 (d) is a graph showing the addition value of the bit value for each sampling pulse, and the addition value of the bit in which the reflected light signal from the object exists is the largest value. Becomes
【0038】従って、ビット毎の加算値を調べることに
よりノイズと反射光信号の識別を行うことができる。こ
のためにCPU1は加算値が最大のビットがサンプリン
グパルスの何番目にあるかということと、サンプリング
周期を基に送光から受光に要した時間を求め、既知であ
るLED光の速度から反射物体までの距離を算出する。Therefore, the noise and the reflected light signal can be distinguished by checking the added value for each bit. For this purpose, the CPU 1 obtains the number of the bit having the largest added value in the sampling pulse and the time required from the light transmission to the light reception based on the sampling period, and obtains the reflection object from the known speed of the LED light. Calculate the distance to.
【0039】この時間算出の分解能はサンプリング周波
数の大きさに依存し、距離算出の分解能に相当する。そ
して、距離算出の分解能の向上は上述のサンプリング周
期を小さくすることにより可能となる。The resolution of the time calculation depends on the size of the sampling frequency, and corresponds to the resolution of the distance calculation. The resolution of the distance calculation can be improved by reducing the sampling period.
【0040】上記により、本発明の車両用の測距センサ
ーヘッドでは測距機能と汚れ検知機能を1つの送光部及
び1つの受光部で共有できるので、前面ガラスの汚れ検
出専用の送光部及び受光部を別に設けることを要しな
い。As described above, in the distance measuring sensor head for a vehicle according to the present invention, the distance measuring function and the dirt detecting function can be shared by one light transmitting unit and one light receiving unit. It is not necessary to separately provide a light receiving unit.
【0041】以上本発明の一実施例について説明した
が、本発明は上記実施例に限定されるものではなく、種
々の変形実施が可能であることはいうまでもない。Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made.
【0042】[0042]
【発明の効果】以上説明したように本発明の測距センサ
ーヘッドによれば、発光部の複数の発光素子のうち少な
くとも1つの発光素子を所定タイミング毎に発光させて
車両前方へ透過部を通して光を出射し、1回の出射光を
出射してからこの出射光に基づく到来光を受光するまで
の往復時間に基づき、自車両と自車両前方の先行移動体
との間の距離を測定することができると同時に、この1
回の出射光を用いて透過部の汚れを判断するので、汚れ
検知専用の発光素子及び受光素子を設けなくても済む。
また、発光素子としてLED等の出力が微弱な素子を用
いた場合、受信信号をサンプリング処理し、加算処理を
行うことにより受信信号から反射光信号を抽出すること
が可能となり、正確な測距を行うことができる。As described above, according to the distance measuring sensor head of the present invention, a small number of the plurality of light emitting elements of the light emitting section are used.
At least one light-emitting element emits light at predetermined timings. <br/> Emits light forward through the transmitting portion, and emits one emitted light to receive incoming light based on the emitted light. based on round trip times, to be able to measure the distance between the vehicle and the vehicle ahead of the preceding mobile simultaneously, the 1
Since the dirt on the transmission part is determined using the emitted light of the first time, it is not necessary to provide a light emitting element and a light receiving element dedicated to dirt detection.
In addition, when an element such as an LED having a weak output is used as a light emitting element, it is possible to extract a reflected light signal from the received signal by sampling the received signal and performing an adding process, thereby achieving accurate distance measurement. It can be carried out.
【0043】また、上記により本発明の測距センサーヘ
ッドは部品点数が少なく簡単な構造で構成でき、小型化
を実現できる。As described above, the distance measuring sensor head according to the present invention can be configured with a simple structure having a small number of parts and can be downsized.
【図1】本発明のクレーム対応図である。FIG. 1 is a diagram corresponding to claims of the present invention.
【図2】本発明に基づく測距センサーヘッドの一実施例
の構成を示すブロック図である。FIG. 2 is a block diagram showing a configuration of an embodiment of a distance measuring sensor head according to the present invention.
【図3】本発明の測距センサーヘッドの基本的動作を示
すフローチャートである。FIG. 3 is a flowchart showing a basic operation of the distance measuring sensor head of the present invention.
【図4】送光LED光及び受光信号の波形図である。FIG. 4 is a waveform diagram of a light transmitting LED light and a light receiving signal.
【図5】反射信号とノイズとの識別処理の説明図であ
る。FIG. 5 is an explanatory diagram of a process of identifying a reflected signal and noise.
【図6】従来の車両用の測距センサーヘッドを用いた車
両間距離測定の一例である。FIG. 6 is an example of the inter-vehicle distance measurement using a conventional vehicle ranging sensor head.
【図7】従来の車両用の測距センサーヘッドの構造の一
例である。FIG. 7 is an example of the structure of a conventional ranging sensor head for a vehicle.
A 発光部 A1 〜An 発光素子 B 透過部 C 受光素子 D 距離算出手段 E 駆動手段 F 汚れ判断手段 1 CPU(発光素子駆動手段,汚れ判別手段,距離算
出手段) 2 送光駆動回路(発光素子駆動手段) 3 発光素子(送光部) 5 センサーヘッドの前面ガラス(カバー) 11 受光素子(受光部) 13 信号処理部(距離算出手段) 16 ガラス面に付着した汚れ 100 測距センサーヘッドReference Signs List A light emitting section A 1 to An light emitting element B transmitting section C light receiving element D distance calculating means E driving means F dirt determining means 1 CPU (light emitting element driving means, dirt determining means, distance calculating means) 2 light transmitting drive circuit (light emitting Element driving means) 3 Light emitting element (light transmitting section) 5 Front glass (cover) of sensor head 11 Light receiving element (light receiving section) 13 Signal processing section (distance calculating means) 16 Dirt attached to glass surface 100 Distance measuring sensor head
Claims (2)
を有する発光部と、この発光部の複数の発光素子のうち少なくとも1つの発
光素子を所定タイミング毎に発光させる駆動手段と、 この発光部による出射光を車両前方の外部へ透過させる
一方、前記出射光に基づく車両前方の外部からの到来光
を車両後方へ透過させる透過部と、 前記発光部の複数の発光素子のうち少くとも1つの発光
素子の出射光による前記透過部での反射光及び前記到来
光を受光する受光素子と、 前記発光部の発光素子が1回の出射光を出射してから前
記受光素子が到来光を受光するまでの往復時間に基づき
自車両と自車両前方の先行移動体との間の距離を算出す
る距離算出手段と、 前記発光部の発光素子が前記1回の出射光を出射した際
に、前記透過部での反射光を前記受光素子で受光した受
光レベルに基づいて前記透過部の汚れを判断する汚れ判
断手段と、 を有することを特徴とする測距センサーヘッド。1. A light emitting section having a plurality of light emitting elements for emitting light forward of a vehicle, and at least one of the plurality of light emitting elements of the light emitting section.
A driving unit for emitting an optical element at predetermined timings, and a transmitting unit for transmitting light emitted from the light emitting unit to the outside in front of the vehicle, and transmitting incoming light from outside in front of the vehicle based on the emitted light to the rear of the vehicle. And a light-receiving element that receives the reflected light and the incoming light at the transmission section due to emission light of at least one of the light-emitting elements of the plurality of light-emitting elements of the light-emitting section ; a distance calculation means for calculating the distance between the light emitted from the emission to the prior movement of the vehicle and the vehicle ahead based on the round-trip time to the light receiving element for receiving the incoming light, light emission of the light emitting portion When the element emits the light once
The distance measuring sensor head characterized by having a a dirt determining means for determining contamination of the transmissive portion based on the reflected light to the light receiving level of light received by the light receiving element in the transmissive portion.
ンプリングパルス毎に所定基準レベルと比較し、前記ア
ナログ信号が前記所定基準レベルを超えるときを
“1”、前記アナログ信号が前記所定基準レベル以下の
ときを“0”に対応させてデジタル信号に変換するサン
プリング手段と、 前記サンプリング手段により変換された前記デジタル信
号を前記サンプリングパルス毎に所定送信回数だけ加算
した加算値を算出する加算手段とを有し、 前記加算値が最大値を示したサンプリングパルスを前記
先行移動体からの反射信号と見なして前記先行移動体と
の距離を算出することを特徴とする請求項1記載の測距
センサーヘッド。 2. The distance calculation means compares an analog signal received by the light receiving element with a predetermined reference level for each sampling pulse of a predetermined frequency, and sets “1” when the analog signal exceeds the predetermined reference level; Sampling means for converting a time when the analog signal is equal to or less than the predetermined reference level into a digital signal in correspondence with "0"; and adding the digital signal converted by the sampling means a predetermined number of times of transmission for each sampling pulse. Adding means for calculating an added value, wherein a distance from the preceding moving object is calculated by regarding the sampling pulse having the maximum value as a reflection signal from the preceding moving object. The distance measuring sensor head according to claim 1 .
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP07471294A JP3146838B2 (en) | 1994-04-13 | 1994-04-13 | Distance sensor head |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP07471294A JP3146838B2 (en) | 1994-04-13 | 1994-04-13 | Distance sensor head |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH07280925A JPH07280925A (en) | 1995-10-27 |
JP3146838B2 true JP3146838B2 (en) | 2001-03-19 |
Family
ID=13555117
Family Applications (1)
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JP07471294A Expired - Fee Related JP3146838B2 (en) | 1994-04-13 | 1994-04-13 | Distance sensor head |
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JP (1) | JP3146838B2 (en) |
Families Citing this family (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3328582B2 (en) * | 1998-05-27 | 2002-09-24 | 株式会社日立製作所 | Inter-vehicle distance measurement device |
DE10041776A1 (en) * | 2000-08-25 | 2002-03-07 | Bosch Gmbh Robert | Rain sensor, in particular for a motor vehicle |
JP3669320B2 (en) * | 2001-10-04 | 2005-07-06 | 日産自動車株式会社 | Inter-vehicle distance measuring device |
JP2005233782A (en) * | 2004-02-19 | 2005-09-02 | Kurita Water Ind Ltd | Method and apparatus for detecting dirt of ultrasonic sensor |
JP4305231B2 (en) * | 2004-03-16 | 2009-07-29 | 株式会社デンソー | Distance detector |
DE102004062022A1 (en) * | 2004-12-23 | 2006-07-13 | Robert Bosch Gmbh | Optical proximity sensor |
JP5710108B2 (en) * | 2009-07-03 | 2015-04-30 | 日本信号株式会社 | Optical distance measuring device |
JP6060021B2 (en) * | 2013-03-29 | 2017-01-11 | 株式会社日立ハイテクノロジーズ | Trajectory inspection method and apparatus |
EP3117234B1 (en) * | 2014-03-14 | 2021-04-28 | Heptagon Micro Optics Pte. Ltd. | Optoelectronic modules operable to recognize spurious reflections and to compensate for errors caused by spurious reflections |
JP2017090380A (en) * | 2015-11-16 | 2017-05-25 | 株式会社デンソーウェーブ | Laser radar device, window member for laser radar device, and control program for laser radar device |
JP6729247B2 (en) * | 2016-09-27 | 2020-07-22 | 株式会社デンソーウェーブ | Non-coaxial laser radar device |
JP6775119B2 (en) * | 2017-03-23 | 2020-10-28 | パナソニックIpマネジメント株式会社 | Distance measuring device |
CN113574411A (en) | 2019-03-14 | 2021-10-29 | 伟摩有限责任公司 | Method and system for detecting an obstacle on a sensor housing |
WO2023112884A1 (en) * | 2021-12-17 | 2023-06-22 | パイオニア株式会社 | Ranging device, determining device, determining method, and program |
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1994
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