JPH0552956A - Optical distance-measuring device - Google Patents
Optical distance-measuring deviceInfo
- Publication number
- JPH0552956A JPH0552956A JP3216973A JP21697391A JPH0552956A JP H0552956 A JPH0552956 A JP H0552956A JP 3216973 A JP3216973 A JP 3216973A JP 21697391 A JP21697391 A JP 21697391A JP H0552956 A JPH0552956 A JP H0552956A
- Authority
- JP
- Japan
- Prior art keywords
- light
- signal
- distance
- level
- light transmission
- 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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- Optical Radar Systems And Details Thereof (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】この発明は、光を所定の方向に送
出し、この送出光の反射体による反射光を受光して、光
の送出から受光までの伝播遅延時間に基づいて、反射体
までの距離を測定する光測距装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention sends light in a predetermined direction, receives reflected light of the sent light by a reflector, and reflects the light based on the propagation delay time from the sending of the light to the receiving of the light. The present invention relates to an optical distance measuring device for measuring the distance to the.
【0002】[0002]
【従来の技術】図3は例えば特開平2−228579号
公報に示された従来の光測距装置の構成を示し、図にお
いて、1はパルス発生器、2はパルス発生器1からの電
気信号を光信号に変換するための発光素子(レーザダイ
オード等)とその駆動回路とレンズ系で構成される送光
器である。2. Description of the Related Art FIG. 3 shows a configuration of a conventional optical distance measuring device disclosed in, for example, Japanese Patent Laid-Open No. 2-228579, in which 1 is a pulse generator and 2 is an electric signal from a pulse generator 1. Is a light-transmitting device including a light-emitting element (laser diode or the like) for converting light into an optical signal, its drive circuit, and a lens system.
【0003】3は反射体による反射光を受光するための
レンズ系と光信号を電気信号に変調するための受光素子
(ホトダイオード等)で構成される受光器、4は受光器
3からのパルス信号を増幅する広帯域増幅器、5はパル
ス発生器1から掃引開始の信号を受ける掃引器とサンプ
ルパルス発生器とサンプルホールド器と低周波増幅器器
で構成されたサンプリング処理器で、広帯域増幅器4か
らの受信パルス信号を低周波受信パルス信号に変換す
る。Reference numeral 3 designates a light receiver comprising a lens system for receiving the light reflected by the reflector and a light receiving element (photodiode or the like) for modulating an optical signal into an electric signal, and 4 a pulse signal from the light receiver 3. A broadband amplifier 5 that amplifies the signal is a sampling processor composed of a sweeper that receives a sweep start signal from the pulse generator 1, a sample pulse generator, a sample hold device, and a low frequency amplifier. The pulse signal is converted into a low frequency reception pulse signal.
【0004】6はサンプリング処理器5のサンプルパル
ス発生器と同期してサンプリング処理器5からの低周波
受信パルス信号の直流レベルを検出するA/D変換器、
7はA/D変換器6の出力と予め所定の値に設定した基
準値と比較する比較器、8はパルス発生器1の信号と比
較器7の出力信号から光の伝播遅延時間をカウントし、
反射体までの距離を算出する信号処理器である。An A / D converter 6 detects the DC level of the low-frequency reception pulse signal from the sampling processor 5 in synchronization with the sampling pulse generator of the sampling processor 5.
Reference numeral 7 denotes a comparator for comparing the output of the A / D converter 6 with a reference value set to a predetermined value in advance, and 8 denotes the propagation delay time of light from the signal of the pulse generator 1 and the output signal of the comparator 7. ,
It is a signal processor that calculates the distance to the reflector.
【0005】次に動作について説明する。パルス発生器
1は、パルス間隔が最大測定距離に対応する時間以上で
あるクロックパルスを発生する。このパルス信号を駆動
パルスとして入力した送光器2は送光パルスLt を送出
する。この送光パルスLt は、測距対象としての反射体
により反射されて反射光Lr となって、受光器3で受光
されて光電変換により電気信号に変換される。Next, the operation will be described. The pulse generator 1 generates a clock pulse whose pulse interval is equal to or longer than the time corresponding to the maximum measurement distance. The light transmitter 2 which has received this pulse signal as a drive pulse transmits a light transmission pulse L t . This light-transmitting pulse L t is reflected by a reflector as a distance measurement target to become reflected light L r , which is received by the light receiver 3 and converted into an electric signal by photoelectric conversion.
【0006】そして、この電気信号は、広帯域増幅器4
により所定のレベル迄増幅された後、サンプリング処理
器5によりその掃引周波数に等しい周波数の低周波信
号、即ち、元の受信パルス信号に対して、時間軸が変換
されただけで形状の保存されたパルス信号に変換される
と共に、必要なレベル迄増幅されて低周波受信パルス信
号となる。Then, this electric signal is supplied to the broadband amplifier 4
After being amplified to a predetermined level by, the shape of the low frequency signal having the same frequency as the sweep frequency, that is, the original received pulse signal is converted by the sampling processor 5, and the shape is preserved only by converting the time axis. It is converted into a pulse signal and amplified to a required level to become a low frequency reception pulse signal.
【0007】次に、A/D変換器6は、サンプリング処
理器5からの低周波受信パルス信号の直流レベルをサン
プリング処理器5のサンプリングパルス発生器のサンプ
リングパルスと同期したタイミングで読み取って、デジ
タル値に変換する。比較器7は、このデジタル値と基準
値と比較し、基準値以上になると信号を出力する。Next, the A / D converter 6 reads the DC level of the low frequency reception pulse signal from the sampling processor 5 at a timing synchronized with the sampling pulse of the sampling pulse generator of the sampling processor 5, and digitally reads it. Convert to a value. The comparator 7 compares the digital value with the reference value and outputs a signal when the value is equal to or larger than the reference value.
【0008】信号処理器8は、パルス発生器1から得ら
れる掃引開始即ち送光のタイミングを示す信号と、比較
器7の出力信号のタイミングから伝播遅延時間をカウン
トし、反射体までの距離を算出する。比較器7の基準値
は、無信号時におけるサンプリング処理器5の出力信号
の直流レベルにノイズによる変動分を加味して、ノイズ
による誤動作が起きない程度のレベル(通常ノイズレベ
ルの10dBアップ値を加える。)に固定値で設定され
る。The signal processor 8 counts the propagation delay time based on the timing of the sweep start, that is, the light transmission timing obtained from the pulse generator 1 and the timing of the output signal of the comparator 7, and determines the distance to the reflector. calculate. The reference value of the comparator 7 is a level at which a malfunction due to noise does not occur by adding a fluctuation amount due to noise to the DC level of the output signal of the sampling processor 5 when there is no signal (a normal noise level is increased by 10 dB. Set to a fixed value.
【0009】この光測距装置は、自動車等の移動物体に
搭載装備されることによって、自車の前方、後方、又は
側方など周辺の反射体の有無の検知や、距離,速度等の
検出を可能とするので、衝突防止,車間距離制御,路面
状況検知,車線変更時の隣接レーンの状況検知等に有効
に使用することができる。This optical distance measuring device is mounted on a moving object such as an automobile to detect the presence or absence of a reflector around the front, rear, or side of the vehicle and to detect distance, speed, etc. Therefore, it can be effectively used for collision prevention, inter-vehicle distance control, road surface condition detection, condition detection of adjacent lanes when changing lanes, and the like.
【0010】[0010]
【発明が解決しようとする課題】従来の光測距装置は以
上のように構成されているので、比較器7の基準値は固
定されており、電源電圧の変動や周囲温度の変化や経年
変化等によりサンプリング処理器5の出力信号の直流レ
ベルがドリフトすると、測定精度の劣化や誤検出の原因
になるので、高精度の定電圧回路や温度保償回路が必要
になり、また、基準値を厳密に設定するための調整が困
難であるなどの問題点があった。Since the conventional optical distance measuring device is constructed as described above, the reference value of the comparator 7 is fixed, and the fluctuation of the power supply voltage, the change of the ambient temperature and the secular change. If the DC level of the output signal of the sampling processor 5 drifts due to factors such as deterioration of measurement accuracy and erroneous detection, a high-precision constant voltage circuit or temperature compensation circuit is required. There was a problem that it was difficult to make adjustments to make strict settings.
【0011】この発明は上記のような問題点を解消する
ためになされたもので、距離計測期間(測距期間)以外
の時間帯の信号レベルに応じて比較用の閾値を自動設定
し、測定精度を向上させる事のできる光測距装置を得る
事を目的とする。The present invention has been made to solve the above-mentioned problems, and a threshold for comparison is automatically set and measured according to the signal level in a time zone other than the distance measurement period (distance measurement period). An object is to obtain an optical distance measuring device that can improve accuracy.
【0012】[0012]
【課題を解決するための手段】この発明に係る光測距装
置は、送光タイミングと比較手段の出力タイミング間の
伝播遅延時間に基づいて反射体迄の距離を測定する装置
において、非測距期間に送光を一時的に休止させる送光
制御手段と、送光休止期間中の無信号時の信号レベルを
基に比較手段の基準値を可変設定する閾値電圧発生手段
を設けたものである。An optical distance measuring device according to the present invention is a device for measuring a distance to a reflector based on a propagation delay time between a light sending timing and an output timing of a comparing means. Light transmission control means for temporarily suspending light transmission during the period and threshold voltage generation means for variably setting the reference value of the comparison means based on the signal level when there is no signal during the light transmission suspension period are provided. ..
【0013】[0013]
【作用】この発明の光測距装置は、測距期間毎の直前に
送光を送光制御手段により休止し、この時の無信号時の
直流レベルを検出し、この検出レベルを基にノイズによ
る変動分を加味して閾値電圧発生手段により比較手段の
基準値を可変設定し、反射体に送受光する事により得ら
れたパルス信号のレベルと比較して、その結果を受光タ
イミングとして、光の伝播遅延時間に基づいて反射体迄
の距離を測定する。The optical distance measuring apparatus of the present invention suspends the light transmission by the light transmission control means immediately before each distance measuring period, detects the direct current level at the time of no signal at this time, and detects noise based on this detection level. The reference value of the comparison means is variably set by the threshold voltage generation means in consideration of the fluctuation due to the light source, and compared with the level of the pulse signal obtained by transmitting and receiving light to the reflector, and the result is used as the light reception timing. The distance to the reflector is measured based on the propagation delay time.
【0014】[0014]
【実施例】以下、この発明の一実施例を図について説明
する。図1はこの発明の一実施例による光測距装置の構
成を示し、図1において、従来例と同一又は相当部分に
は図3と同一符号1〜8を付し、その説明を省略する。
9は次の測距サイクルの測距期間直前である測距期間以
外の時間帯に送光を一時的に休止するための信号を送光
器2に発生する送光制御器、10は上記時間帯の送光休
止中にA/D変換器6により検出したサンプリング処理
器5の出力信号の直流レベルに、ノイズによる変動分を
加味して、比較器7の閾値電圧を発生する閾値電圧発生
器である。DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of an optical distance measuring apparatus according to an embodiment of the present invention. In FIG. 1, the same or corresponding parts as those in the conventional example are designated by the same reference numerals 1 to 8 as those in FIG.
Reference numeral 9 is a light transmission controller that generates a signal for temporarily stopping the light transmission to the light transmitter 2 in a time zone other than the distance measurement period immediately before the distance measurement period of the next distance measurement cycle. A threshold voltage generator for generating the threshold voltage of the comparator 7 by adding fluctuations due to noise to the DC level of the output signal of the sampling processor 5 detected by the A / D converter 6 while the light transmission of the band is stopped. Is.
【0015】図2はこの発明の一実施例の距離測定タイ
ミングを説明するための図であり、測距サイクル1回分
を示している。図2において、時刻t0 で測距を開始
し、90ms後の時刻t1 で測距を終了すると共にデー
タ転送を開始し、時刻t1 から10ms後の時刻t2 で
データ転送を終了する。時刻t0 〜t1 の90msは、
測距期間,送光期間,受信レベル検出期間となる。時刻
t1 〜t2の10msは、距離データ転送期間、送光休
止期間,無信号レベル検出期間となる。従って、測距サ
イクルは、時刻t0 〜t2 で、100msとなる。FIG. 2 is a diagram for explaining the distance measurement timing of one embodiment of the present invention, showing one distance measurement cycle. In FIG. 2, the distance measurement is started at time t 0 , the distance measurement is ended at time t 1 after 90 ms and the data transfer is started, and the data transfer is ended at time t 2 10 ms after the time t 1 . 90 ms from time t 0 to t 1
It is a distance measurement period, a light transmission period, and a reception level detection period. 10 ms from time t 1 to t 2 is the distance data transfer period, the light transmission pause period, and the no-signal level detection period. Therefore, the distance measurement cycle is 100 ms from time t 0 to t 2 .
【0016】次に、図1及び図2を参照してこの一実施
例の動作について説明する。時刻t0 〜t1 の測距期間
は、比較器7の基準値が固定値でなく、閾値電圧発生器
10により測距サイクル毎に予め自動設定される事以
外、従来の光測距装置と同じ動作をする。この動作は、
従来の技術の欄で述べたので、その説明を省略する。Next, the operation of this embodiment will be described with reference to FIGS. During the distance measurement period from time t 0 to t 1 , the reference value of the comparator 7 is not a fixed value, and is set automatically by the threshold voltage generator 10 in advance for each distance measurement cycle. Do the same. This behavior is
Since it has been described in the section of the related art, its description is omitted.
【0017】次に、時刻t1 〜t2 の動作について説明
する。信号処理器8から測距終了信号を受けた送光制御
器9は、この距離データ転送期間中、送光器2からの送
光を休止するための信号を発生し、送光器2に出力し、
送光を休止させる。一方、バックグラウンド光は、受光
器3により受光されて光電変換された後に広帯域増幅器
4を介してサンプリング処理器5にてサンプリング処理
される。Next, the operation at times t 1 to t 2 will be described. Upon receiving the distance measurement end signal from the signal processor 8, the light transmission controller 9 generates a signal for stopping the light transmission from the light transmitter 2 during the distance data transfer period, and outputs the signal to the light transmitter 2. Then
Pause light transmission. On the other hand, the background light is received by the light receiver 3 and photoelectrically converted, and then subjected to sampling processing by the sampling processor 5 via the broadband amplifier 4.
【0018】このサンプリング処理器5から出力される
信号は、送光による低周波受信パルス信号即ち測距用信
号が無い時の無信号時の信号で、A/D変換器6により
直流レベルを検出される。閾値電圧発生器10は、A/
D変換器6により検出されたこの直流レベルにノイズに
よる変動分を加味して、ノイズによる誤動作が発生しな
い程度のレベルの閾値電圧を設定し、比較器7へ基準値
として供給し、次回の測距サイクルの測距期間に備え
る。The signal output from the sampling processor 5 is a low frequency reception pulse signal by light transmission, that is, a signal when there is no distance measuring signal, and a DC level is detected by the A / D converter 6. To be done. The threshold voltage generator 10 is A /
In addition to this DC level detected by the D converter 6, fluctuations due to noise are added to set a threshold voltage at a level at which malfunction due to noise does not occur, and the threshold voltage is supplied to the comparator 7 as a reference value. Prepare for the distance measurement period of the distance cycle.
【0019】この他に、STC(センシティブ タイミ
ング コントロール)的特性を持たせるために、送光休
止期間中の無信号時の直流レベルに加味するノイズによ
る変動分を測定する距離に応じて変動させるような場合
にも、無信号時の直流レベルを測距サイクル毎の直前に
検出した値に更新することにより上記実施例と同様の効
果が得られる。In addition to this, in order to have an STC (sensitive timing control) characteristic, the fluctuation due to noise added to the DC level when there is no signal during the light transmission suspension period is changed according to the distance to be measured. Even in such a case, the same effect as that of the above-described embodiment can be obtained by updating the DC level when there is no signal to the value detected immediately before each ranging cycle.
【0020】[0020]
【発明の効果】以上のように、この発明によれば測距期
間以外の時間帯に送光を一時的に休止させ、この送光休
止期間中に無信号時の信号レベルを検出し、この検出レ
ベルを基に比較用の基準値を可変設定するように構成し
たので、高精度の定電圧回路や複雑な温度補償回路を使
用しなくても、測距精度の向上が図れ、簡単な構成で製
造し易いものが得られる効果がある。As described above, according to the present invention, the light transmission is temporarily stopped during the time period other than the distance measurement period, and the signal level when there is no signal is detected during the light transmission suspension period. Since the reference value for comparison is variably set based on the detection level, distance measurement accuracy can be improved without using a highly accurate constant voltage circuit or a complicated temperature compensation circuit, and a simple configuration is possible. There is an effect that it is easy to manufacture.
【図1】この発明の一実施例による光測距装置の構成を
示すブロック図である。FIG. 1 is a block diagram showing a configuration of an optical distance measuring device according to an embodiment of the present invention.
【図2】上記一実施例による測距サイクル1回分の動作
期間を示す説明図である。FIG. 2 is an explanatory diagram showing an operation period for one distance measurement cycle according to the embodiment.
【図3】従来の光測距装置の構成を示すブロック図であ
る。FIG. 3 is a block diagram showing a configuration of a conventional optical distance measuring device.
1 パルス発生器 2 送光器(送光手段) 3 受光器 4 広帯域増幅器 5 サンプリング処理器 6 A/D変換器(検出手段) 7 比較器(比較手段) 8 信号処理器 9 送光制御器(送光制御手段) 10 閾値電圧発生器(閾値電圧発生手段) 1 pulse generator 2 light transmitter (light transmitting means) 3 light receiver 4 broadband amplifier 5 sampling processor 6 A / D converter (detecting means) 7 comparator (comparing means) 8 signal processor 9 light transmitting controller ( Light transmission control means) 10 Threshold voltage generator (threshold voltage generation means)
【手続補正書】[Procedure amendment]
【提出日】平成4年5月15日[Submission date] May 15, 1992
【手続補正1】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】0004[Correction target item name] 0004
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【0004】6はサンプリング処理器5のサンプルパル
ス発生器と同期してサンプリング処理器5からの低周波
受信パルス信号の直流レベルを検出するA/D変換器、
7はA/D変換器6の出力と予め所定の値に設定した基
準値とを比較する比較器、8はパルス発生器1の信号と
比較器7の出力信号から光の伝播遅延時間をカウント
し、反射体までの距離を算出する信号処理器である。An A / D converter 6 detects the DC level of the low-frequency reception pulse signal from the sampling processor 5 in synchronization with the sampling pulse generator of the sampling processor 5.
Reference numeral 7 is a comparator for comparing the output of the A / D converter 6 with a reference value set in advance to a predetermined value, and 8 is the propagation delay time of light from the signal of the pulse generator 1 and the output signal of the comparator 7. A signal processor for calculating the distance to the reflector.
Claims (1)
光パルスの反射体による反射光を受光する事により得ら
れたパルス信号のレベルを検出する検出手段と、該検出
手段により検出された信号レベルと基準値を比較する比
較手段を備え、送光タイミングと上記比較手段の出力変
化タイミング間の伝播遅延時間に基づいて上記反射体迄
の距離を測定する光測距装置において、測距期間以外の
時間帯に送光を一時的に休止させる送光制御手段と、該
送光休止期間中に上記検出手段により検出された無信号
時の信号レベルを基に上記比較手段の基準値を次回の測
距サイクル用に可変設定する閾値電圧発生手段を備えた
事を特徴とする光測距装置。1. A light transmitting means for transmitting a light transmitting pulse, a detecting means for detecting a level of a pulse signal obtained by receiving reflected light of the light transmitting pulse by a reflector, and a detecting means for detecting the level of the pulse signal. In the optical distance measuring device, which is provided with a comparison means for comparing the signal level and the reference value, the distance to the reflector is measured based on the propagation delay time between the light transmission timing and the output change timing of the comparison means. Light transmission control means for temporarily suspending light transmission in a time zone other than the distance period, and a reference value of the comparison means based on the signal level when there is no signal detected by the detection means during the light transmission suspension period. An optical distance measuring device comprising: a threshold voltage generating means for variably setting for the next distance measuring cycle.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3216973A JPH0552956A (en) | 1991-08-28 | 1991-08-28 | Optical distance-measuring device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3216973A JPH0552956A (en) | 1991-08-28 | 1991-08-28 | Optical distance-measuring device |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0552956A true JPH0552956A (en) | 1993-03-02 |
Family
ID=16696823
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3216973A Pending JPH0552956A (en) | 1991-08-28 | 1991-08-28 | Optical distance-measuring device |
Country Status (1)
Country | Link |
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JP (1) | JPH0552956A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1061336A2 (en) | 1999-06-15 | 2000-12-20 | Kabushiki Kaisha Topcon | Distance measuring apparatus and method |
JP2013096905A (en) * | 2011-11-02 | 2013-05-20 | Denso Corp | Distance measuring apparatus |
JP2019015522A (en) * | 2017-07-03 | 2019-01-31 | オムロンオートモーティブエレクトロニクス株式会社 | Distance measuring device |
JP2020153708A (en) * | 2019-03-18 | 2020-09-24 | 株式会社東芝 | Electronic device and method therefor |
JP2021518549A (en) * | 2018-03-20 | 2021-08-02 | パノセンス インコーポレイテッド | Selection of LIDAR pulse detector according to pulse type |
-
1991
- 1991-08-28 JP JP3216973A patent/JPH0552956A/en active Pending
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1061336A2 (en) | 1999-06-15 | 2000-12-20 | Kabushiki Kaisha Topcon | Distance measuring apparatus and method |
EP1061336A3 (en) * | 1999-06-15 | 2004-12-29 | Kabushiki Kaisha Topcon | Distance measuring apparatus and method |
JP2013096905A (en) * | 2011-11-02 | 2013-05-20 | Denso Corp | Distance measuring apparatus |
JP2019015522A (en) * | 2017-07-03 | 2019-01-31 | オムロンオートモーティブエレクトロニクス株式会社 | Distance measuring device |
JP2021518549A (en) * | 2018-03-20 | 2021-08-02 | パノセンス インコーポレイテッド | Selection of LIDAR pulse detector according to pulse type |
US11681029B2 (en) | 2018-03-20 | 2023-06-20 | Zoox, Inc. | Detecting a laser pulse edge for real time detection |
JP2020153708A (en) * | 2019-03-18 | 2020-09-24 | 株式会社東芝 | Electronic device and method therefor |
US11598859B2 (en) | 2019-03-18 | 2023-03-07 | Kabushiki Kaisha Toshiba | Electronic apparatus and method |
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