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JP2020071164A - Distance measuring device - Google Patents

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JP2020071164A
JP2020071164A JP2018206357A JP2018206357A JP2020071164A JP 2020071164 A JP2020071164 A JP 2020071164A JP 2018206357 A JP2018206357 A JP 2018206357A JP 2018206357 A JP2018206357 A JP 2018206357A JP 2020071164 A JP2020071164 A JP 2020071164A
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light
pulsed light
pulsed
measuring device
distance measuring
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JP7256631B2 (en
Inventor
松原　弘幸
Hiroyuki Matsubara
弘幸 松原
勇 高井
Isamu Takai
勇 高井
峰樹 曽我
Mineki Soga
峰樹 曽我
木村　禎祐
Sadasuke Kimura
禎祐 木村
尾崎　憲幸
Noriyuki Ozaki
憲幸 尾崎
武廣 秦
Takehiro Hata
武廣 秦
謙太 東
Kenta Azuma
謙太 東
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Denso Corp
Toyota Central R&D Labs Inc
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Denso Corp
Toyota Central R&D Labs Inc
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Priority to JP2018206357A priority Critical patent/JP7256631B2/en
Priority to PCT/JP2019/042624 priority patent/WO2020090911A1/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C3/00—Measuring distances in line of sight; Optical rangefinders
    • G01C3/02—Details
    • G01C3/06—Use of electric means to obtain final indication
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/484—Transmitters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/497—Means for monitoring or calibrating

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Electromagnetism (AREA)
  • Optical Radar Systems And Details Thereof (AREA)
  • Measurement Of Optical Distance (AREA)

Abstract

【課題】物体からの反射信号を高い感度で検出することが可能な距離測定装置を提供する。【解決手段】パルス光を出力する光照射部１０と、光を受光し、受光強度の時間変化を強度波形として取得する受光部１２と、強度波形に含まれるパルス光の反射光に基づいて物体までの距離を算出する信号処理部１４と、を備え、光照射部１０は、第１パルス光と第１パルス光に対して波形及び出力タイミングの少なくとも一方を変更した第２パルス光とを出力し、信号処理部１４は、第１パルス光の反射光を含む強度波形と第２パルス光の反射光を含む強度波形とを処理することによって測定対象物２００までの距離を算出する距離測定装置１００とする。【選択図】図１PROBLEM TO BE SOLVED: To provide a distance measuring device capable of detecting a reflected signal from an object with high sensitivity. SOLUTION: An object is based on a light irradiation unit 10 that outputs pulsed light, a light receiving unit 12 that receives light and acquires a time change of light receiving intensity as an intensity waveform, and reflected light of pulsed light included in the intensity waveform. A signal processing unit 14 for calculating the distance to the light is provided, and the light irradiation unit 10 outputs the first pulse light and the second pulse light in which at least one of the waveform and the output timing is changed with respect to the first pulse light. Then, the signal processing unit 14 is a distance measuring device that calculates the distance to the object to be measured 200 by processing the intensity waveform including the reflected light of the first pulse light and the intensity waveform including the reflected light of the second pulse light. Let it be 100. [Selection diagram] Fig. 1

Description

本発明は、距離測定装置に関する。   The present invention relates to a distance measuring device.

光源からパルス光を照射し、物体によって反射された反射光を受光することによって、物体までの距離を測定する距離測定装置が知られている。   There is known a distance measuring device that measures a distance to an object by emitting pulsed light from a light source and receiving reflected light reflected by the object.

レーザ光を測定対象物に向けて照射する送信光学系と、照射されたのち測定対象物により反射されたレーザ光の反射光を受信する受信光学系と、受信光学系による反射光の受信信号をサンプリングし、今回サンプリングの受信信号の信号強度が前回サンプリングの受信信号の信号強度より低ければ、今回サンプリングの受信信号の信号強度と受信時刻を用いて伝搬経路上の媒質を起因とするレーザ光のエネルギーの減衰係数を算出する減衰係数算出手段と、算出された減衰係数を用いて受信光学系による反射光の受信信号の信号強度を補償する信号強度補償手段と、信号強度が補償された受信信号の中から測定対象物に係る受信信号を抽出して受信信号に対応するレーザ光の送信時刻と受信信号の受信時刻との差から測定対象物までの距離を導出する距離導出手段とを備えたレーザレーダ装置が開示されている（特許文献１）。また、外乱による反射成分を関数でフィッティングして、そのフィッティングされた外乱成分を除去する方法が開示されている（非特許文献１）。   A transmission optical system that irradiates the laser light toward the measurement object, a reception optical system that receives the reflected light of the laser light that is irradiated and then reflected by the measurement object, and a reception signal of the reflection light by the reception optical system. If the signal strength of the received signal of this sampling is lower than the signal strength of the previously sampled received signal, the signal strength of the received signal of this sampling and the reception time are used to determine the laser light caused by the medium on the propagation path. Attenuation coefficient calculating means for calculating the attenuation coefficient of energy, signal strength compensating means for compensating the signal strength of the received signal of the reflected light by the receiving optical system using the calculated attenuation coefficient, and the received signal with the signal strength compensated The received signal related to the measurement object is extracted from the The laser radar apparatus and a distance deriving unit that output has been disclosed (Patent Document 1). Further, a method of fitting a reflection component due to a disturbance with a function and removing the fitted disturbance component is disclosed (Non-Patent Document 1).

また、複数の反射ピークを検出するマルチエコー検出型のレーザレーダにおいて霧などの外乱による反射ピークを除外する方法が開示されている（特許文献２〜４）。   Further, a method of excluding a reflection peak due to a disturbance such as fog in a laser echo of a multi-echo detection type that detects a plurality of reflection peaks is disclosed (Patent Documents 2 to 4).

特開２０１３−１２４８８２号公報JP, 2013-124882, A 特開２０１０−２８６３０７号公報JP, 2010-286307, A 特開２０１３−１６７４７９号公報JP, 2013-167479, A 特開２０１７−２１９３８３号公報JP, 2017-219383, A

Ｇ．Ｓａｔａｔ， ｅｔ ａｌ．， “Ｔｏｗａｒｄｓ Ｐｈｏｔｏｇｒａｐｈｙ Ｔｈｒｏｕｇｈ Ｒｅａｌｉｓｔｉｃ Ｆｏｇ”， ＩＥＥＥ ＩＣＣＰ， ２０１８．G. Satat, et al. , "Towards Photography Through Realistic Fog", IEEE ICCP, 2018.

ところで、特許文献２〜４の技術では、外乱光のピークを除去するだけであり、物体光と重なっている成分は除去できない。そのため、物体光の信号ノイズ比（Ｓ／Ｎ）は向上させることができない。   By the way, in the techniques of Patent Documents 2 to 4, only the peak of the ambient light is removed, and the component overlapping with the object light cannot be removed. Therefore, the signal noise ratio (S / N) of the object light cannot be improved.

また、特許文献１及び非特許文献１の技術では、外乱散乱光の波形を均一な外乱と近似してフィッティングしている。そのため、外乱の原因となる物質の空間的な濃度分布にむらがある場合に対して効果的ではない。   Further, in the techniques of Patent Document 1 and Non-Patent Document 1, the waveform of the disturbance scattered light is approximated to a uniform disturbance for fitting. Therefore, it is not effective when the spatial concentration distribution of the substance causing the disturbance is uneven.

本発明の１つの態様は、パルス光を出力する光照射部と、光を受光し、受光強度の時間変化を強度波形として取得する受光部と、前記強度波形に含まれる前記パルス光の反射光に基づいて物体までの距離を算出する信号処理部と、を備え、前記光照射部は、第１パルス光と、前記第１パルス光に対して波形及び出力タイミングの少なくとも一方を変更した第２パルス光と、を出力し、前記信号処理部は、前記第１パルス光の反射光を含む前記強度波形と前記第２パルス光の反射光を含む前記強度波形とを処理することによって前記物体までの距離を算出することを特徴とする距離測定装置である。   One aspect of the present invention is a light irradiation unit that outputs pulsed light, a light receiving unit that receives light and acquires a temporal change in received light intensity as an intensity waveform, and reflected light of the pulsed light included in the intensity waveform. A signal processing unit that calculates a distance to an object based on the first pulsed light, and the light irradiation unit changes at least one of a waveform and an output timing with respect to the first pulsed light. Pulsed light is output, and the signal processing unit processes the intensity waveform including the reflected light of the first pulsed light and the intensity waveform including the reflected light of the second pulsed light to the object. The distance measuring device is characterized by calculating the distance.

ここで、前記信号処理部は、前記第１パルス光の反射光を含む前記強度波形と前記第２パルス光の反射光を含む前記強度波形との線形加算の波形から前記物体までの距離を算出することが好適である。   Here, the signal processing unit calculates the distance to the object from a linear addition waveform of the intensity waveform including the reflected light of the first pulsed light and the intensity waveform including the reflected light of the second pulsed light. Is preferred.

また、前記第１パルス光と前記第２パルス光とは出力エネルギーが等しく、前記信号処理部は、前記第１パルス光の反射光を含む前記強度波形と前記第２パルス光の反射光を含む前記強度波形との差分波形から前記物体までの距離を算出することが好適である。   The first pulsed light and the second pulsed light have the same output energy, and the signal processing unit includes the intensity waveform including the reflected light of the first pulsed light and the reflected light of the second pulsed light. It is preferable to calculate the distance to the object from the difference waveform with the intensity waveform.

また、前記第２パルス光は出力タイミングが異なる複数の信号の線形和からなることを特徴とすることが好適である。   Further, it is preferable that the second pulsed light includes a linear sum of a plurality of signals having different output timings.

また、前記第２パルス光は、前記第１パルス光よりパルス幅が広い波形を有し、前記光照射部は、所定の条件を満たすときのみ前記第２パルス光を出力することが好適である。   Further, it is preferable that the second pulsed light has a waveform having a pulse width wider than that of the first pulsed light, and the light irradiation unit outputs the second pulsed light only when a predetermined condition is satisfied. ..

また、前記第１パルス光と前記第２パルス光は異なる波長であり、前記受光部は、前記第１パルス光の反射光と前記第２パルス光の反射光に対してそれぞれ異なる受光素子を備えてもよい。   Further, the first pulsed light and the second pulsed light have different wavelengths, and the light receiving section includes different light receiving elements for the reflected light of the first pulsed light and the reflected light of the second pulsed light. May be.

本発明によれば、天候などによる後方散乱光の影響を除去し、物体からの反射信号を高い感度で検出することが可能な距離測定装置を提供することができる。   According to the present invention, it is possible to provide a distance measuring device capable of removing the influence of backscattered light due to weather or the like and detecting a reflection signal from an object with high sensitivity.

第１の実施の形態の距離測定装置の構成を示す図である。It is a figure which shows the structure of the distance measuring device of 1st Embodiment. 第１の実施の形態の強度波形Ｓ１，Ｓ２及び補正信号Ｓの例を示す図である。It is a figure which shows the example of intensity | strength waveform S1, S2 and correction signal S of 1st Embodiment. 第２の実施の形態の強度波形Ｓ１，Ｓ２及び補正信号Ｓの例を示す図である。It is a figure which shows the example of intensity | strength waveform S1 and S2 of 2nd Embodiment, and the correction signal S. 第３の実施の形態の強度波形Ｓ１，Ｓ２及び補正信号Ｓの例を示す図である。It is a figure which shows the example of intensity | strength waveform S1, S2 and correction signal S of 3rd Embodiment. 第４の実施の形態の距離測定装置の構成を示す図である。It is a figure which shows the structure of the distance measuring device of 4th Embodiment. 第５の実施の形態の距離測定装置の構成を示す図である。It is a figure which shows the structure of the distance measuring device of 5th Embodiment.

［第１の実施の形態］
第１の実施の形態における距離測定装置１００は、図１に示すように、光照射部１０、受光部１２及び信号処理部１４を含んで構成される。光照射部１０、受光部１２及び信号処理部１４は同一の筐体内に収めることができる。 [First Embodiment]
As shown in FIG. 1, the distance measuring device 100 according to the first embodiment is configured to include a light irradiation unit 10, a light receiving unit 12, and a signal processing unit 14. The light irradiation unit 10, the light receiving unit 12, and the signal processing unit 14 can be housed in the same housing.

距離測定装置１００は、光照射部１０から所定の波長λＬＤのパルス光を出力し、測定対象物２００において反射された反射光を受光部１２にて受光することにより測定対象物２００までの距離を測定するために用いられる。 The distance measuring device 100 outputs pulsed light having a predetermined wavelength λ LD from the light irradiation unit 10 and receives the reflected light reflected by the measuring object 200 by the light receiving unit 12 to measure the distance to the measuring object 200. Used to measure.

光照射部１０は、距離測定装置１００において測距に利用される光を出射する。光照射部１０は、レーザダイオード（ＬＤ）や液晶（ＬＥＤ）とすることができる。光照射部１０は、例えば、中心発光波長λＬＤが（８７０ｎｍといった）赤外線の帯域であるＬＤを使用してもよい。ただし、光照射部１０から照射される光の波長は、これに限定されるものではなく、測定対象物２００において反射され、受光部１２において当該反射光が受光できる波長の電磁波であればよい。 The light irradiation unit 10 emits light used for distance measurement in the distance measuring device 100. The light irradiation unit 10 can be a laser diode (LD) or a liquid crystal (LED). The light irradiation unit 10 may use, for example, an LD having a central emission wavelength λ LD in the infrared band (such as 870 nm). However, the wavelength of the light emitted from the light irradiation unit 10 is not limited to this, and may be any electromagnetic wave having a wavelength that is reflected by the measurement object 200 and that the reflected light can be received by the light receiving unit 12.

本実施の形態では、光照射部１０からパルス光が出力される。光照射部１０からパルス光が出射されると、その出射時刻ｔ０が信号処理部１４に入力される。 In the present embodiment, the light irradiation section 10 outputs pulsed light. When the pulsed light is emitted from the light irradiation unit 10, the emission time t 0 is input to the signal processing unit 14.

また、光照射部１０から光を広範囲に照射するための手段を設けてもよい。例えば、ポリゴンミラーを回転させて、光照射部１０から出力される光の照射角度を変更できる構成としてもよい。   Further, means for irradiating the light from the light irradiating section 10 over a wide range may be provided. For example, the polygon mirror may be rotated to change the irradiation angle of the light output from the light irradiation unit 10.

受光部１２は、受光素子を含んで構成される。受光部１２は、例えば、複数の受光素子を配列させた構成とされる。例えば、縦４個×横４個の合計１６個の受光素子をアレイ状に並べた構成とすることができる。ただし、受光部１２における受光素子の配置は、これに限定されるものではなく、単一の受光素子で構成してもよいし、複数の受光素子を１次元的又は２次元的に配置するような構成としてもよい。   The light receiving unit 12 includes a light receiving element. The light receiving unit 12 has, for example, a configuration in which a plurality of light receiving elements are arranged. For example, a total of 16 light receiving elements, 4 vertically by 4 horizontally, can be arranged in an array. However, the arrangement of the light receiving elements in the light receiving unit 12 is not limited to this, and may be configured by a single light receiving element, or a plurality of light receiving elements may be arranged one-dimensionally or two-dimensionally. It may have any configuration.

受光部１２の各受光素子に光が入射すると、光の強度に応じた電気信号に変換されて信号処理部１４へ強度信号が出力される。したがって、受光部１２から出力される強度信号の時間的変化から強度波形を取得することができる。   When light is incident on each light receiving element of the light receiving unit 12, it is converted into an electric signal corresponding to the intensity of the light and the intensity signal is output to the signal processing unit 14. Therefore, the intensity waveform can be acquired from the temporal change of the intensity signal output from the light receiving unit 12.

信号処理部１４は、受光部１２において取得された強度波形を処理して、距離測定装置１００から測定対象物２００までの距離を算出する。すなわち、信号処理部１４は、受光部１２において取得された信号の強度波形に含まれるパルス光の反射光に基づいて物体までの距離を算出する。具体的には、光照射部１０から出力されたパルス光を測定対象物２００が反射した反射光の成分を受光部１２で取得した信号の強度波形から抽出し、当該パルス光の出射時刻ｔ０から当該パルス光の反射光の受光時刻ｔｄとの差分Δｔ（＝ｔｄ−ｔ０）に基づいて距離測定装置１００から測定対象物２００までの距離を演算する。すなわち、信号処理部１４は、差分Δｔに光速ｃを乗算し、それを２で割ることで測定対象物２００までの距離Ｄを求める。 The signal processing unit 14 processes the intensity waveform acquired by the light receiving unit 12 to calculate the distance from the distance measuring device 100 to the measurement object 200. That is, the signal processing unit 14 calculates the distance to the object based on the reflected light of the pulsed light included in the intensity waveform of the signal acquired by the light receiving unit 12. Specifically, the pulsed light output from the light irradiation unit 10 is extracted from the intensity waveform of the signal obtained by the light receiving unit 12 of the reflected light component reflected by the measurement object 200, and the emission time t 0 of the pulsed light is extracted. Then, the distance from the distance measuring device 100 to the measurement object 200 is calculated based on the difference Δt (= t d −t 0 ) from the reception time t d of the reflected light of the pulsed light. That is, the signal processing unit 14 multiplies the difference Δt by the speed of light c and divides it by 2 to obtain the distance D to the measurement object 200.

本実施の形態における距離測定装置１００では、光照射部１０は、第１パルス光と、第１パルス光に対して波形及び出力タイミングの少なくとも一方を変更した第２パルス光とを出力する。そして、信号処理部１４は、第１パルス光の反射光を含む強度波形と第２パルス光の反射光を含む強度波形とを処理することによって物体までの距離を算出する。   In distance measuring apparatus 100 in the present embodiment, light irradiation unit 10 outputs the first pulsed light and the second pulsed light in which at least one of the waveform and the output timing is changed with respect to the first pulsed light. Then, the signal processing unit 14 calculates the distance to the object by processing the intensity waveform including the reflected light of the first pulsed light and the intensity waveform including the reflected light of the second pulsed light.

図２（ａ）は、第１パルス光（エネルギーＥ１）を出力し、測定対象物２００によって反射された第１パルス光の反射光を受光部１２において受光したときの強度波形Ｓ１の例を示す。また、図２（ｂ）は、第１パルス光よりもパルス幅が広い第２パルス光（エネルギーＥ２）を出力し、測定対象物２００によって反射された第２パルス光の反射光を受光部１２において受光したときの強度波形Ｓ２の例を示す。   FIG. 2A illustrates an example of the intensity waveform S1 when the first pulsed light (energy E1) is output and the reflected light of the first pulsed light reflected by the measurement object 200 is received by the light receiving unit 12. .. 2B, the second pulsed light (energy E2) having a pulse width wider than that of the first pulsed light is output, and the reflected light of the second pulsed light reflected by the measuring object 200 is received by the light receiving unit 12. An example of the intensity waveform S2 when light is received at is shown.

このとき、霧、煙、粉塵等の外乱散乱体はパルス光の照射の奥行方向に拡がっているため、外乱散乱対による反射光の信号は強度波形Ｓ１，Ｓ２において時間的に拡がったバックグラウンド信号として検出される。このように拡がったバックグラウンド信号を時間的に積算するとパルスエネルギーに比例した大きさとなる。一方、測定対象物２００からの反射光は、測定対象物２００の表面からの反射だけであり、光照射部１０から出力した第１パルス光又は第２パルス光と略同じ波形となる。   At this time, since the disturbance scatterers such as fog, smoke, and dust spread in the depth direction of the irradiation of the pulsed light, the signal of the reflected light by the disturbance scatter pair is a background signal that spreads temporally in the intensity waveforms S1 and S2. Is detected as. When the background signals thus spread are integrated in terms of time, the magnitude is proportional to the pulse energy. On the other hand, the reflected light from the measurement target 200 is only the reflection from the surface of the measurement target 200, and has substantially the same waveform as the first pulsed light or the second pulsed light output from the light irradiation unit 10.

信号処理部１４は、第１パルス光の反射光を含む強度波形Ｓ１と第２パルス光の反射光を含む強度波形Ｓ２をもとに、数式（１）を用いて線形加算した補正信号Ｓを算出する。これによって、散乱外乱信号を除去した補正信号Ｓを得ることができる。ただし、補正信号Ｓには、近距離部分に補償しきれない外乱成分が残る。これについては、強度波形Ｓ１との比較（ピーク高さや位置など）によって、外乱ピークであることを推定して除外することが可能である。
（数１）
Ｓ＝Ｓ１×Ｅ２−Ｓ２×Ｅ１・・・（１） The signal processing unit 14 linearly adds the correction signal S using Equation (1) based on the intensity waveform S1 including the reflected light of the first pulsed light and the intensity waveform S2 including the reflected light of the second pulsed light. calculate. Thereby, the correction signal S from which the scattered disturbance signal is removed can be obtained. However, in the correction signal S, a disturbance component that cannot be completely compensated remains in the short distance portion. With respect to this, it is possible to estimate and exclude the disturbance peak by comparison with the intensity waveform S1 (peak height, position, etc.).
(Equation 1)
S = S1 × E2-S2 × E1 (1)

このように、第１パルス光の反射光を含む強度波形Ｓ１と第２パルス光の反射光を含む強度波形Ｓ２に基づいて外乱散乱体からの反射の影響を除去した補正信号Ｓを求めることで強度信号の信号ノイズ比（Ｓ／Ｎ）を向上させることができる。そして、補正信号Ｓに基づいてパルス光の反射光の受光時刻ｔｄを求めることによって、距離測定装置１００から測定対象物２００までの距離Ｄをより高い精度及び確度で求めることができる。 In this way, the correction signal S from which the influence of the reflection from the disturbance scatterer is removed is obtained based on the intensity waveform S1 including the reflected light of the first pulsed light and the intensity waveform S2 including the reflected light of the second pulsed light. The signal noise ratio (S / N) of the intensity signal can be improved. Then, by obtaining the reception time t d of the reflected light of the pulsed light based on the correction signal S, the distance D from the distance measuring device 100 to the measurement object 200 can be obtained with higher accuracy and accuracy.

なお、第１パルス光のエネルギーＥ１と第２パルス光のエネルギーＥ２が等しい場合（Ｅ１＝Ｅ２）、数式（２）を用いて差分波形を算出することで補正信号Ｓを求めることができる。
（数２）
Ｓ＝Ｓ１−Ｓ２・・・（２） When the energy E1 of the first pulsed light and the energy E2 of the second pulsed light are equal (E 1 = E 2 ), the correction signal S can be obtained by calculating the differential waveform using the mathematical expression (2). ..
(Equation 2)
S = S1-S2 (2)

また、強度波形Ｓ１，Ｓ２を求める際に、１回の測定結果ではなく、複数回の合計又は平均を算出することによって、背景光ノイズやショットノイズといったランダムノイズを低減することができる。   Further, when obtaining the intensity waveforms S1 and S2, random noise such as background light noise and shot noise can be reduced by calculating not a single measurement result but a plurality of sums or averages.

なお、２つの強度波形Ｓ１，Ｓ２を用いることは散乱外乱光を除去するのに有効であるが、散乱外乱光が無い場合には信号ノイズ比（Ｓ／Ｎ）の観点から不利になる場合がある。したがって、強度波形Ｓ１から特開２０１３−１６７４７９等に記載された方法で散乱外乱光がある程度強いと判定できた場合にのみ２つの強度波形Ｓ１，Ｓ２を用いた散乱外乱除去処理を適用することが好適である。例えば、通常は第１パルス光のみを出力するようにしておき、強度波形Ｓ１において散乱外乱光がある程度強いと判定できた場合にのみ第２パルス光を照射して強度波形Ｓ２を取得するようにしてもよい。   The use of the two intensity waveforms S1 and S2 is effective for removing the scattered disturbance light, but may be disadvantageous from the viewpoint of the signal noise ratio (S / N) when there is no scattered disturbance light. is there. Therefore, the scattering disturbance removal processing using the two intensity waveforms S1 and S2 can be applied only when it is possible to determine from the intensity waveform S1 that the scattered disturbance light is strong to some extent by the method described in JP2013-167479A or the like. It is suitable. For example, normally, only the first pulsed light is output, and the second pulsed light is emitted to acquire the intensity waveform S2 only when it can be determined that the scattered disturbance light is strong to some extent in the intensity waveform S1. May be.

［第２の実施の形態］
第１の実施の形態における距離測定装置１００では、光照射部１０から出力される第１パルス光と第２パルス光とはパルス幅の中心が一致するように設定した。これに対して、第１パルス光と第２パルス光との出力タイミングを異なるようにしてもよい。 [Second Embodiment]
In the distance measuring device 100 according to the first embodiment, the first pulsed light and the second pulsed light output from the light irradiation unit 10 are set so that the centers of the pulse widths thereof coincide with each other. On the other hand, the output timings of the first pulsed light and the second pulsed light may be different.

図３（ａ）は、第１パルス光を出力し、測定対象物２００によって反射された第１パルス光の反射光を受光部１２において受光したときの強度波形Ｓ１の例を示す。また、図３（ｂ）は、第１パルス光よりもパルス幅が広く、パルスの立ち上がりの位置を第１パルス光に揃えた第２パルス光を出力し、測定対象物２００によって反射された第２パルス光の反射光を受光部１２において受光したときの強度波形Ｓ２の例を示す。   FIG. 3A shows an example of the intensity waveform S <b> 1 when the first pulsed light is output and the reflected light of the first pulsed light reflected by the measurement object 200 is received by the light receiving unit 12. Further, FIG. 3B shows a second pulsed light which has a pulse width wider than that of the first pulsed light and whose rising position of the pulse is aligned with the first pulsed light and which is reflected by the measurement object 200. An example of the intensity waveform S2 when the reflected light of the 2-pulse light is received by the light receiving unit 12 is shown.

このような強度波形Ｓ１，Ｓ２について上記数式（１）を用いて補正信号Ｓを求めた場合、第１パルス光と第２パルス光の中心位置が揃っている場合に比べて信号のピーク位置で引かれる量が小さくなり、より大きいピークを得ることができる。ただし、外乱散乱成分の影響がより大きくなる可能性がある。   When the correction signal S is obtained for the intensity waveforms S1 and S2 by using the above mathematical expression (1), the peak position of the signal is higher than that when the center positions of the first pulse light and the second pulse light are aligned. A smaller amount can be drawn, and a larger peak can be obtained. However, the influence of the disturbance scattering component may become larger.

［第３の実施の形態］
また、光照射部１０から出力される第１パルス光の数と第２パルス光の数とを異ならせるようにしてもよい。 [Third Embodiment]
Further, the number of first pulsed lights and the number of second pulsed lights output from the light irradiation unit 10 may be different.

図４（ａ）は、第１パルス光として１つのパルス光を出力し、測定対象物２００によって反射された第１パルス光の反射光を受光部１２において受光したときの強度波形Ｓ１の例を示す。また、図４（ｂ）は、第２パルス光として２つのパルス光を出力し、測定対象物２００によって反射された第２パルス光の反射光を受光部１２において受光したときの強度波形Ｓ２の例を示す。   FIG. 4A shows an example of the intensity waveform S1 when one pulsed light is output as the first pulsed light and the reflected light of the first pulsed light reflected by the measurement object 200 is received by the light receiving unit 12. Show. In addition, FIG. 4B shows an intensity waveform S2 when two pulsed lights are output as the second pulsed light and the reflected light of the second pulsed light reflected by the measurement object 200 is received by the light receiving unit 12. Here is an example:

すなわち、第１パルス光よりパルス幅が広い第２パルス光とする代わりに、第１パルス光とパルス幅が同程度又は狭い２つのパルスを含む第２パルス光を用いる。このとき、第２パルス光に含まれるパルスのピーク位置が第１パルス光のピーク位置を避けるようにすることが好適である。   That is, instead of using the second pulsed light having a pulse width wider than that of the first pulsed light, the second pulsed light including two pulses having the same or narrower pulse width as the first pulsed light is used. At this time, it is preferable that the peak position of the pulse included in the second pulsed light avoids the peak position of the first pulsed light.

なお、第１パルス光と第２パルス光のパルス波形は相似形である必要はない。また、２つの連続したパルスの代わりに、それぞれ個別に発光して得られた信号の線形和を第２パルス光としてもよい。   The pulse waveforms of the first pulsed light and the second pulsed light do not have to have similar shapes. Further, instead of two continuous pulses, a linear sum of signals obtained by individually emitting light may be used as the second pulse light.

このような強度波形Ｓ１，Ｓ２について上記数式（１）を用いて補正信号Ｓを求めた場合、信号のピークの強度の減少を抑制しつつ、外乱散乱成分を除去することができる。   When the correction signal S is obtained for the intensity waveforms S1 and S2 using the above mathematical expression (1), the disturbance scattering component can be removed while suppressing the decrease in the intensity of the signal peak.

［第４の実施の形態］
図５は、第４の実施の形態における距離測定装置１０２の構成を示す。距離測定装置１０２では、光源として２つの光照射部１０ａ及び光照射部１０ｂが設けられている。光照射部１０ａは、第１パルス光を照射するための光源として機能し、光照射部１０ｂは、第２パルス光を照射するための光源として機能する。このとき、受光部１２の受光開口部から遠い位置に第１パルス光を出力する光照射部１０ａを配置し、近い位置に第１パルス光よりパルス幅が広い第２パルス光を出力する光照射部１０ｂを配置することが好適である。 [Fourth Embodiment]
FIG. 5 shows the configuration of the distance measuring device 102 according to the fourth embodiment. In the distance measuring device 102, two light irradiation units 10a and 10b are provided as light sources. The light irradiation unit 10a functions as a light source for irradiating the first pulsed light, and the light irradiation unit 10b functions as a light source for irradiating the second pulsed light. At this time, the light irradiation unit 10a for outputting the first pulsed light is arranged at a position far from the light receiving opening of the light receiving unit 12, and the light irradiation for outputting the second pulsed light having a wider pulse width than the first pulsed light is arranged at a position near the light receiving unit. It is preferable to arrange the portion 10b.

このように、２つの光照射部１０ａ及び光照射部１０ｂを配置することによって、強度波形の近距離範囲に残ってしまう外乱信号を低減することができる。なお、光照射部１０を１つのみにした場合、第１パルス光及び第２パルス光を同じ照度分布で照射できるので、補償精度がよくなるという利点がある。   In this way, by disposing the two light irradiation units 10a and 10b, it is possible to reduce the disturbance signal that remains in the short range of the intensity waveform. When only one light irradiation unit 10 is provided, it is possible to irradiate the first pulsed light and the second pulsed light with the same illuminance distribution, which is advantageous in improving the compensation accuracy.

［第５の実施の形態］
図６は、第５の実施の形態における距離測定装置１０４の構成を示す。距離測定装置１０４は、光源として２つの光照射部１０ａ及び光照射部１０ｂ並びに２つの受光素子として受光部１２ａ及び受光部１２ｂを備える。 [Fifth Embodiment]
FIG. 6 shows the configuration of the distance measuring device 104 according to the fifth embodiment. The distance measuring device 104 includes two light emitting units 10a and 10b as light sources and two light receiving units 12a and 12b as two light receiving elements.

光照射部１０ａは、第１パルス光を照射するための光源として機能し、光照射部１０ｂは、第２パルス光を照射するための光源として機能する。本実施の形態では、光照射部１０ａと光照射部１０ｂは互いに異なる波長の光を出力する。例えば、光照射部１０ａは波長λ１の第１パルス光を出力し、光照射部１０ｂは波長λ２の第２パルス光を出力する。光照射部１０ａ及び光照射部１０ｂからそれぞれ出力された第１パルス光及び第２パルス光は、２色合成用のハーフミラー１６によって合成されて外部へ照射される。   The light irradiation unit 10a functions as a light source for irradiating the first pulsed light, and the light irradiation unit 10b functions as a light source for irradiating the second pulsed light. In the present embodiment, the light irradiation unit 10a and the light irradiation unit 10b output lights having different wavelengths. For example, the light irradiation unit 10a outputs the first pulsed light of the wavelength λ1, and the light irradiation unit 10b outputs the second pulsed light of the wavelength λ2. The first pulsed light and the second pulsed light output from the light irradiator 10a and the light irradiator 10b are combined by the half mirror 16 for two-color combination and are radiated to the outside.

受光部１２ａは、第１パルス光の波長の光を受光する手段として機能し、受光部１２ｂは、第２パルス光の波長の光を受光する手段として機能する。例えば、光照射部１０ａは波長λ１の光を受光し、光照射部１０ｂは波長λ２の光を受光する。本実施の形態では、外部から入射された光は、２色分離用のハーフミラー１８によって第１パルス光の波長の光と第２パルス光の波長の光に分離されてそれぞれ受光部１２ａ及び受光部１２ｂへ導入される。   The light receiving unit 12a functions as a unit that receives light having the wavelength of the first pulsed light, and the light receiving unit 12b functions as a unit that receives light having the wavelength of the second pulsed light. For example, the light irradiation unit 10a receives light of wavelength λ1, and the light irradiation unit 10b receives light of wavelength λ2. In the present embodiment, the light incident from the outside is separated into the light of the wavelength of the first pulsed light and the light of the wavelength of the second pulsed light by the half-mirror 18 for two-color separation, and the light is received at the light receiving portion 12a and the light receiving portion 12a. It is introduced into section 12b.

このように、第１パルス光と第２パルス光との波長を異ならせることによって、第１パルス光と第２パルス光とを同時に照射し、それぞれの波長の光を分離して受光することによって強度波形Ｓ１と強度波形Ｓ２とを同時に取得することができる。これにより、強度波形Ｓ１と強度波形Ｓ２との計測時刻の差による環境変化等の影響を低減することができる。したがって、補正信号Ｓにおける環境変化等の影響も低減することができ、距離測定の精度及び確度を向上することができる。   As described above, by making the wavelengths of the first pulsed light and the second pulsed light different from each other, the first pulsed light and the second pulsed light are simultaneously irradiated, and the light of each wavelength is separated and received. The intensity waveform S1 and the intensity waveform S2 can be acquired at the same time. As a result, it is possible to reduce the influence of environmental changes and the like due to the difference in measurement time between the intensity waveform S1 and the intensity waveform S2. Therefore, it is possible to reduce the influence of environmental changes on the correction signal S, and improve the accuracy and accuracy of distance measurement.

１０（１０ａ，１０ｂ） 光照射部、１２（１２ａ，１２ｂ） 受光部、１４ 信号処理部、１６ ハーフミラー、１８ ハーフミラー、１００，１０２，１０４ 距離測定装置、２００ 測定対象物。
10 (10a, 10b) light irradiation part, 12 (12a, 12b) light receiving part, 14 signal processing part, 16 half mirror, 18 half mirror, 100, 102, 104 distance measuring device, 200 measurement object.

Claims (6)

パルス光を出力する光照射部と、
光を受光し、受光強度の時間変化を強度波形として取得する受光部と、
前記強度波形に含まれる前記パルス光の反射光に基づいて物体までの距離を算出する信号処理部と、
を備え、
前記光照射部は、第１パルス光と、前記第１パルス光に対して波形及び出力タイミングの少なくとも一方を変更した第２パルス光と、を出力し、
前記信号処理部は、前記第１パルス光の反射光を含む前記強度波形と前記第２パルス光の反射光を含む前記強度波形とを処理することによって前記物体までの距離を算出することを特徴とする距離測定装置。 A light irradiation unit that outputs pulsed light,
A light receiving unit that receives light and acquires the time change of the received light intensity as an intensity waveform,
A signal processing unit that calculates a distance to an object based on reflected light of the pulsed light included in the intensity waveform,
Equipped with
The light irradiation unit outputs a first pulsed light and a second pulsed light in which at least one of a waveform and an output timing is changed with respect to the first pulsed light,
The signal processing unit calculates a distance to the object by processing the intensity waveform including the reflected light of the first pulsed light and the intensity waveform including the reflected light of the second pulsed light. And distance measuring device. 請求項１に記載の距離測定装置であって、
前記信号処理部は、前記第１パルス光の反射光を含む前記強度波形と前記第２パルス光の反射光を含む前記強度波形との線形加算の波形から前記物体までの距離を算出することを特徴とする距離測定装置。 The distance measuring device according to claim 1,
The signal processing unit may calculate a distance to the object from a linear addition waveform of the intensity waveform including the reflected light of the first pulsed light and the intensity waveform including the reflected light of the second pulsed light. Characteristic distance measuring device. 請求項２に記載の距離測定装置であって、
前記第１パルス光と前記第２パルス光とは出力エネルギーが等しく、前記信号処理部は、前記第１パルス光の反射光を含む前記強度波形と前記第２パルス光の反射光を含む前記強度波形との差分波形から前記物体までの距離を算出することを特徴とする距離測定装置。 The distance measuring device according to claim 2,
The first pulsed light and the second pulsed light have the same output energy, and the signal processing unit includes the intensity waveform including the reflected light of the first pulsed light and the intensity including the reflected light of the second pulsed light. A distance measuring device, wherein a distance to the object is calculated from a difference waveform from the waveform. 請求項１に記載の距離測定装置であって、
前記第２パルス光は出力タイミングが異なる複数の信号の線形和からなることを特徴とする距離測定装置。 The distance measuring device according to claim 1,
The distance measuring device, wherein the second pulsed light is a linear sum of a plurality of signals having different output timings. 請求項１に記載の距離測定装置であって、
前記第２パルス光は、前記第１パルス光よりパルス幅が広い波形を有し、
前記光照射部は、所定の条件を満たすときのみ前記第２パルス光を出力することを特徴とする距離測定装置。 The distance measuring device according to claim 1,
The second pulsed light has a waveform having a pulse width wider than that of the first pulsed light,
The distance measuring device, wherein the light irradiation section outputs the second pulsed light only when a predetermined condition is satisfied. 請求項１〜５のいずれか１項に記載の距離測定装置であって、
前記第１パルス光と前記第２パルス光は異なる波長であり、
前記受光部は、前記第１パルス光の反射光と前記第２パルス光の反射光に対してそれぞれ異なる受光素子を備えることを特徴する距離測定装置。
The distance measuring device according to any one of claims 1 to 5,
The first pulsed light and the second pulsed light have different wavelengths,
The distance measuring device, wherein the light receiving section includes different light receiving elements for the reflected light of the first pulsed light and the reflected light of the second pulsed light.
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