JP4772474B2 - Optical distance measuring method - Google Patents

Optical distance measuring method Download PDF

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JP4772474B2
JP4772474B2 JP2005339248A JP2005339248A JP4772474B2 JP 4772474 B2 JP4772474 B2 JP 4772474B2 JP 2005339248 A JP2005339248 A JP 2005339248A JP 2005339248 A JP2005339248 A JP 2005339248A JP 4772474 B2 JP4772474 B2 JP 4772474B2
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利宏 森
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Hokuyo Automatic Co Ltd
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Description

本発明は、光を用いて被測定物までの距離を演算する光学式測距方法に関する。   The present invention relates to an optical distance measuring method for calculating a distance to an object to be measured using light.

周知のように、光を用いて被測定物までの距離を測定する光学式測距方法は、発光素子から出射された測距光を被測定物に対して送光し、被測定物で反射した測距光を受光素子で受光して電気信号である測距信号に変換し、この変換された測距信号に基づいて被測定物までの距離を演算する方法である。具体的には、例えば測距光の送光から受光までの時間差や、位相差等の距離情報を測距信号から求め、かかる距離情報から被測定物までの距離が演算される。   As is well known, the optical distance measuring method for measuring the distance to the object to be measured using light transmits the distance measuring light emitted from the light emitting element to the object to be measured, and is reflected by the object to be measured. In this method, the distance measuring light received by the light receiving element is converted into a distance measuring signal which is an electric signal, and the distance to the object to be measured is calculated based on the converted distance measuring signal. Specifically, for example, distance information such as a time difference from a distance measurement light transmission to a light reception and a phase difference is obtained from the distance measurement signal, and the distance to the object to be measured is calculated from the distance information.

そして、この種の光学式測距方法は、被測定物で反射した測距光の光量が反射時に散乱等によって弱められることを考慮し、受光素子で受光された測距光に対応して生成される測距信号をアンプによって増幅し、この増幅された測距信号に基づいて被測定物までの距離が演算されるのが通例である。   This type of optical distance measuring method is generated corresponding to the distance measuring light received by the light receiving element in consideration that the amount of distance measuring light reflected by the object to be measured is weakened by scattering or the like at the time of reflection. In general, the distance measurement signal is amplified by an amplifier, and the distance to the object to be measured is calculated based on the amplified distance measurement signal.

しかしながら、受光素子で受光される測距光の光量レベルは、被測定物の測距光に対する反射率や、被測定物までの距離等によって種々に変動し、受光素子で受光される測距光に対応した測距信号の信号レベルのダイナミックレンジは必然的に大きくなる。そのため、アンプの増幅率を、微弱な信号レベルの測距信号を増幅するのに十分なレベルに設定した場合には、より大きな信号レベルの測距信号がアンプに入力された際に、アンプで増幅された測距信号が飽和するという問題がある。   However, the light level of the distance measuring light received by the light receiving element varies depending on the reflectance of the object to be measured with respect to the distance measuring light, the distance to the object to be measured, etc., and the distance measuring light received by the light receiving element. The dynamic range of the signal level of the distance measurement signal corresponding to inevitably increases. Therefore, when the amplification factor of the amplifier is set to a level sufficient to amplify a ranging signal with a weak signal level, when the ranging signal with a larger signal level is input to the amplifier, the amplifier There is a problem that the amplified ranging signal is saturated.

そこで、上記の問題に対処する方法として、アンプにＡＧＣ（Ａｕｔｏｍａｔｉｃ Ｇａｉｎ Ｃｏｎｔｒｏｌ）回路を取り付けて、ある一定のレベル以上の信号レベルをもつ測距信号がアンプに入力された場合には、ＡＧＣ回路によってアンプの増幅率を自動的に下げて、アンプの出力信号の飽和を防ぐ方法が公知となっている（例えば、下記の特許文献１参照）。   Therefore, as a method of coping with the above problem, when an AGC (Automatic Gain Control) circuit is attached to the amplifier and a ranging signal having a signal level higher than a certain level is input to the amplifier, the AGC circuit A method of automatically reducing the amplification factor of the amplifier to prevent saturation of the output signal of the amplifier is known (for example, see Patent Document 1 below).

特開２００４−３６３６７８号公報JP 2004-363678 A

ところで、近年、この種の光学式測距方法においては、その利用分野の拡大に伴って、被測定物までの距離をより一層高精度に測定することが要求されるに至っているのが実情である。   By the way, in recent years, in this type of optical distance measuring method, as the field of use expands, it is actually required to measure the distance to the object to be measured with higher accuracy. is there.

しかしながら、上記の特許文献１に開示されているように、単にＡＧＣ回路をアンプに取り付けて測距信号を増幅しただけでは、増幅された測距信号の飽和に起因した誤差の発生を防止することはできるものの、その他の要因による誤差の発生は依然として解消されないため、上記の要求に十分に応じることができないという問題がある。   However, as disclosed in the above-mentioned Patent Document 1, simply amplifying a distance measurement signal by attaching an AGC circuit to an amplifier prevents the occurrence of an error due to saturation of the amplified distance measurement signal. However, the occurrence of errors due to other factors is still not resolved, and thus there is a problem that the above-mentioned requirements cannot be fully met.

本発明の課題は、アンプにＡＧＣ回路を取り付けた上で、演算距離に含まれる誤差を的確に補正して被測定物までの距離を高精度に測定することにある。   An object of the present invention is to accurately measure an error included in a calculation distance and accurately measure a distance to an object to be measured after an AGC circuit is attached to an amplifier.

本発明は、ＡＧＣ回路の作動の有無に応じてアンプの特性が変化するという知見、および、被測定物までの演算距離に含まれる誤差が、ＡＧＣ回路が非作動となる状態では被測定物までの距離の変化を主たる要因として発生し、ＡＧＣ回路が作動している状態では被測定物までの距離の変化と、受光素子で受光される測距光の光量レベルの変化とを主たる要因として発生するという知見に基づいてなされたものである。   The present invention is based on the knowledge that the characteristics of the amplifier change depending on whether or not the AGC circuit is activated, and the error included in the calculation distance to the object to be measured is the same as the object to be measured when the AGC circuit is inactive. This is mainly caused by the change in the distance to the object to be measured and the change in the light level of the ranging light received by the light receiving element when the AGC circuit is operating. It was made based on the knowledge to do.

すなわち、上記課題を解決するために創案された本発明は、発光素子から出射される測距光を被測定物に向けて送光し、前記被測定物で反射した測距光を受光素子で受光すると共に測距信号に変換し、前記受光素子で変換された測距信号の信号レベルに応じてＡＧＣ回路が作動して増幅率が自動的に下げられるアンプで前記測距信号を増幅し、前記アンプで増幅された前記測距信号に基づいて前記被測定物までの距離を演算する光学式測距方法において、前記被測定物の距離測定前に、前記ＡＧＣ回路が非作動となる範囲で、前記受光素子で受光される測距光の光量を一定に保ちながら複数の既知距離を測定し、各既知距離での演算距離に応じた距離補正値を示す第一補正関数を求めると共に、前記ＡＧＣ回路が作動する範囲で、前記受光素子に受光される測距光の光量レベルを変化させながら単一の既知距離を測定し、各光量レベルでの演算距離に応じた距離補正値を示す第二補正関数を求め、前記被測定物の距離測定時に、前記ＡＧＣ回路が非作動状態にある場合には、前記第一補正関数に基づいて前記被測定物までの演算距離を補正し、前記ＡＧＣ回路が作動状態にある場合には、前記第一補正関数および前記第二補正関数に基づいて前記被測定物までの演算距離を補正することに特徴づけられる。 That is, the present invention devised to solve the above-described problem is that the distance measuring light emitted from the light emitting element is transmitted toward the object to be measured, and the distance measuring light reflected by the object to be measured is received by the light receiving element. Receives light and converts it to a ranging signal, and the AGC circuit is activated according to the signal level of the ranging signal converted by the light receiving element to amplify the ranging signal with an amplifier whose amplification factor is automatically lowered, In an optical distance measuring method for calculating a distance to the object to be measured based on the distance measurement signal amplified by the amplifier, before the distance measurement of the object to be measured, the AGC circuit is deactivated. Measuring a plurality of known distances while maintaining a constant amount of ranging light received by the light receiving element, obtaining a first correction function indicating a distance correction value according to a calculation distance at each known distance, and In the range where the AGC circuit operates, the light receiving element Obtains a second correction function while varying the light level measured single known distance, shows the distance correction value according to the calculated distance for each light level of the distance measuring light received by the light, of the object to be measured At the time of distance measurement, when the AGC circuit is in an inoperative state, the calculation distance to the object to be measured is corrected based on the first correction function, and when the AGC circuit is in an activated state, It is characterized in that the calculation distance to the object to be measured is corrected based on the first correction function and the second correction function.

上記の方法によれば、被測定物の距離測定時に、ＡＧＣ回路が非作動状態にある場合には、被測定物までの距離の変化を考慮した距離補正値を示す第一補正関数に基づいて被測定物までの演算距離が補正される。一方、被測定物の距離測定時に、ＡＧＣ回路が作動状態にある場合には、上記の第一補正関数と、受光素子に受光される測距光の光量レベルの変化を考慮した距離補正値を示す第二補正関数とに基づいて被測定物までの演算距離が補正される。したがって、被測定物の距離測定時に、ＡＧＣ回路の作動の有無に応じて、予め求められた第一補正関数と第二補正関数が的確に選択されると共に、選択された補正関数に基づいて被測定物までの演算距離が補正されるため、結果として被測定物の距離を高精度に測定することが可能となる。   According to the above method, when the AGC circuit is in an inoperative state when measuring the distance of the object to be measured, based on the first correction function indicating the distance correction value considering the change in the distance to the object to be measured. The calculation distance to the object to be measured is corrected. On the other hand, if the AGC circuit is in an operating state when measuring the distance of the object to be measured, the distance correction value considering the first correction function and the change in the light level of the distance measuring light received by the light receiving element is obtained. The calculated distance to the object to be measured is corrected based on the second correction function shown. Therefore, when the distance of the object to be measured is measured, the first correction function and the second correction function obtained in advance are accurately selected according to whether or not the AGC circuit is activated, and the object to be measured is determined based on the selected correction function. Since the calculation distance to the measurement object is corrected, as a result, the distance of the measurement object can be measured with high accuracy.

上記の方法において、更に、第一基準反射部材と第二基準反射部材とをそれぞれ所定位置に配置して前記発光素子から出射される測距光の一部を各基準反射部材に対して送光し、前記第一基準反射部材で測距光を前記ＡＧＣ回路が非作動となる範囲の光量レベルに調整して反射すると共に、前記受光素子で受光される前記第一基準反射部材で反射した測距光に基づいて前記第一補正関数を修正し、且つ、前記第二基準反射部材で前記測距光を前記ＡＧＣ回路が作動する範囲の光量レベルに調整して反射すると共に、前記受光素子で受光される前記第二基準反射部材で反射した前記測距光に基づいて前記第二補正関数を修正することが好ましい。 In the above method, the first reference reflecting member and the second reference reflecting member are arranged at predetermined positions, respectively, and a part of the ranging light emitted from the light emitting element is transmitted to each reference reflecting member. Then, the distance measuring light is adjusted by the first reference reflecting member to reflect the light amount level in a range where the AGC circuit is not operated, and is reflected by the first reference reflecting member received by the light receiving element. The first correction function is corrected based on the distance light, and the distance measurement light is adjusted by the second reference reflection member to reflect the light amount level within a range in which the AGC circuit operates, and is reflected by the light receiving element. It is preferable that the second correction function is corrected based on the distance measuring light reflected by the received second reference reflecting member.

このようにすれば、仮に、被測定物までの演算距離が、環境変化や経年変化によって変動を来す場合であっても、所定位置に配置した第一基準反射部材および第二基準反射部材で反射して受光素子で受光される各測距光が、環境変化や経年変化に応じた所定の変化を示すため、その変化量に基づいて、第一補正関数および第二補正関数を修正すれば、環境変化や経年変化に依存しない、より高精度な距離測定を行うことが可能となる。   In this way, even if the calculation distance to the object to be measured varies due to environmental changes and secular changes, the first reference reflecting member and the second reference reflecting member arranged at predetermined positions. Since each distance measuring light reflected and received by the light receiving element shows a predetermined change according to an environmental change or a secular change, if the first correction function and the second correction function are corrected based on the change amount, It becomes possible to perform distance measurement with higher accuracy that does not depend on environmental changes or aging.

上記の方法において、更に、前記被測定物の距離測定前に、前記ＡＧＣ回路が非作動となる範囲であって且つ前記測距信号のレベルが所定値以下の範囲で、前記受光素子で受光される前記測距光の光量を一定に保ちながら複数の既知距離を測定し、各既知距離での演算距離に応じた距離補正量を示す第三補正関数を求め、前記被測定物の距離測定時に、前記ＡＧＣ回路が非作動状態にあって且つ前記測距信号のレベルが前記所定値以下の場合には、前記第一補正関数に代えて前記第三補正関数に基づいて前記被測定物までの演算距離を補正するようにしてもよい。 In the above method, before the distance measurement of the object to be measured, the light receiving element receives light within a range where the AGC circuit is inoperative and the level of the distance measurement signal is a predetermined value or less. that said a maintaining amount of distance measuring light constant is determined a known distance al multiple third obtain a correction function number indicating the distance correction amount corresponding to the calculated distance of each known distance, the object to be measured If the AGC circuit is in an inoperative state and the distance measurement signal level is equal to or lower than the predetermined value when the distance is measured, instead of the first correction function, the object is based on the third correction function. You may make it correct | amend the calculation distance to a measurement object.

このようにすれば、仮に被測定物で反射して受光素子に入射する測距光の光量レベルが弱く、受光素子で変換された測距信号が、ノイズの影響を受ける場合であっても、ノイズの影響を考慮した第三補正関数に基づいて、被測定物までの演算距離に補正が加えられる。 In this way, if weak light levels of the measuring light incident on the light-receiving element and reflected by the object to be measured, ranging signal converted by the light receiving element, even if affected by noise Based on the third correction function that takes into account the influence of noise, the calculation distance to the object to be measured is corrected.

上記の方法において、更に、第三基準反射部材を所定位置に配置して前記発光素子から出射される測距光の一部を前記第三基準反射部材に対して送光し、前記第三基準反射部材で測距光を前記ＡＧＣ回路が非作動となり且つ前記測距信号のレベルが前記所定値以下となる光量レベルに調整して反射すると共に、前記受光素子で受光される前記第三基準反射部材で反射した測距光に基づいて前記第三補正関数を修正することが好ましい。 In the above method, the third reference reflecting member is further disposed at a predetermined position, and a part of the ranging light emitted from the light emitting element is transmitted to the third reference reflecting member, and the third reference The third reference reflection received by the light receiving element while reflecting the distance measuring light by the reflecting member while adjusting the light amount level so that the AGC circuit is not activated and the level of the distance measuring signal is not more than the predetermined value. It is preferable that the third correction function is corrected based on the distance measuring light reflected by the member.

このようにすれば、所定距離に配置した第三基準反射部材によって、受光素子に入射した測距光は、環境変化や経年変化に応じた所定の変化を示すため、この測距光の変化量に基づいて第三補正関数を修正すれば、被測定物までの演算距離に環境変化等に依存しない的確な補正を行うことが可能となり、結果としてより高精度な距離演算を行うことが可能となる。   In this way, the distance measuring light incident on the light receiving element by the third reference reflecting member disposed at a predetermined distance exhibits a predetermined change corresponding to an environmental change or a secular change. If the third correction function is corrected based on the above, it is possible to accurately correct the calculation distance to the object to be measured without depending on environmental changes, etc., and as a result, more accurate distance calculation can be performed. Become.

以上のような本発明によれば、被測定物の距離測定時にＡＧＣ回路の作動の有無に応じて、予め求めた各補正関数が的確に選択されると共に、選択された補正関数に基づいて被測定物までの演算距離に含まれる誤差が補正されるため、結果として被測定物までの距離を高精度に測定することが可能となる。   According to the present invention as described above, each correction function obtained in advance is accurately selected according to whether or not the AGC circuit is activated during distance measurement of the object to be measured, and the object to be measured is selected based on the selected correction function. Since the error included in the calculated distance to the measurement object is corrected, as a result, the distance to the measurement object can be measured with high accuracy.

以下、本発明に係る第一実施形態を図面に基づいて説明する。   Hereinafter, a first embodiment according to the present invention will be described with reference to the drawings.

図１は、第一実施形態に係る光学式測距方法を体現するための光学式測距装置の全体構成を模式的に示すブロック図である。同図に示すように、この光学式測距装置１は、制御部２と、発光素子駆動部３と、発光素子４と、受光素子５と、アンプ６と、ＡＧＣ回路７とを基本的構成要素として備えている。   FIG. 1 is a block diagram schematically showing the overall configuration of an optical distance measuring device for embodying the optical distance measuring method according to the first embodiment. As shown in the figure, this optical distance measuring device 1 has a basic configuration comprising a control unit 2, a light emitting element driving unit 3, a light emitting element 4, a light receiving element 5, an amplifier 6, and an AGC circuit 7. As an element.

詳述すると、制御部２は、発光信号を生成すると共に、発光信号を発光素子駆動部３に入力する。発光素子駆動部３は、入力された発光信号を、発光素子４が駆動するのに必要な大きさに増幅すると共に、増幅した発光信号を発光素子４に入力する。発光素子４は、入力された増幅後の発光信号を、光信号である測距光に変換すると共に、その測距光を被測定物８に対して送光する。   More specifically, the control unit 2 generates a light emission signal and inputs the light emission signal to the light emitting element driving unit 3. The light emitting element driving unit 3 amplifies the input light emission signal to a size necessary for the light emitting element 4 to drive, and inputs the amplified light emission signal to the light emitting element 4. The light emitting element 4 converts the input amplified light emission signal into distance measuring light, which is an optical signal, and transmits the distance measuring light to the object 8 to be measured.

一方、受光素子５は、被測定物８で反射した測距光を受光すると共に、その測距光を電気信号である測距信号に変換し、変換した測距信号をアンプ６に入力する。アンプ６は、入力された測距信号を増幅すると共に、増幅した測距信号を制御部２に入力する。このとき、アンプ６に取り付けられたＡＧＣ回路７は、測距信号の信号レベルが所定の閾値（以下、飽和信号レベルという）を超えた場合にアンプ６の増幅率を自動的に下げ、アンプ６で増幅された測距信号が飽和するのを防止するようになっている。さらに、制御部２は、入力された増幅後の測距信号に基づいて被測定物８までの距離を演算するようになっている。   On the other hand, the light receiving element 5 receives the distance measuring light reflected by the object 8 to be measured, converts the distance measuring light into a distance measuring signal which is an electric signal, and inputs the converted distance measuring signal to the amplifier 6. The amplifier 6 amplifies the input ranging signal and inputs the amplified ranging signal to the control unit 2. At this time, the AGC circuit 7 attached to the amplifier 6 automatically reduces the amplification factor of the amplifier 6 when the signal level of the distance measurement signal exceeds a predetermined threshold (hereinafter referred to as a saturation signal level). This prevents the ranging signal amplified in step S from being saturated. Furthermore, the control unit 2 calculates the distance to the device under test 8 based on the inputted distance measurement signal after amplification.

次に、上記のように構成された光学式測距装置１の光学式測距方法を、被測定物８までの演算距離の補正方法を中心に説明する。   Next, an optical distance measuring method of the optical distance measuring apparatus 1 configured as described above will be described focusing on a method for correcting a calculation distance to the object 8 to be measured.

まず、被測定物８の距離測定前に、被測定物８までの演算距離に応じた距離補正値を示す補正関数を作成し、制御部２の図示しないメモリに記憶する。この補正関数は、本実施形態では第一補正関数、第二補正関数および第三補正関数から構成されており、各補正関数は、以下の手順で作成される。   First, before measuring the distance of the device under test 8, a correction function indicating a distance correction value corresponding to the calculated distance to the device under test 8 is created and stored in a memory (not shown) of the control unit 2. In this embodiment, this correction function is composed of a first correction function, a second correction function, and a third correction function, and each correction function is created by the following procedure.

上記の第一補正関数の作成手順を図２に基づいて説明する。図２に示すように、所定の反射率を有する反射板９を、予め距離が既知である所定の既知距離に配置して上で、この反射板９に向けて発光素子４から出射された測距光を送光し、反射板９で反射した測距光を、測距光の透過光量レベルを調整可能な光量調整部材１０を介して受光素子５へ入射する。このとき、ＡＧＣ回路７が非作動となる範囲であって測距信号に対してノイズの影響が無視できる範囲（測距信号のレベルが所定値以下の範囲）で、光量調整部材１０によって受光素子５に入射する測距光の光量レベルを一定に保ち、反射板９までの距離を演算する。そして、反射板９までの演算距離Ｌ１と実距離との差を距離補正値ΔＬ1として、演算距離Ｌ1と共に制御部２の図示しないメモリに書き込んでいく。次いで、光量調整部材１０によって受光素子５に入射する測距光の光量レベルを一定に保った状態で、反射板９の複数の既知距離に順次配置して、各既知距離における距離補正値ΔＬ 1 と、演算距離Ｌ 1 とを制御部２のメモリに書き込んでいく。以下同様にして、任意の演算距離Ｌ1に対する距離補正値ΔＬ1を示す第一補正関数ｆ1（Ｌ1）が制御部２のメモリに記憶される。なお、上記の「ＡＧＣ回路７が非作動状態となる範囲」とは、ＡＧＣ回路７によってアンプ６の増幅率が自動調整されない状態、すなわちアンプ６に予め設定された所定の増幅率で測距信号が増幅される状態を意味し、具体的には、例えばアンプ６で増幅された測距信号の信号レベルが、アンプ６の飽和信号レベル以下となる範囲に設定される。また、上記の「測距信号に対してノイズの影響が無視できる範囲」とは、例えばアンプ６で増幅された測距信号の信号レベルが、アンプ６の飽和信号レベルの１０％以上となる範囲に設定される。また、上記の「ノイズ」としては、例えば発光素子４を駆動する信号が電気的に結合されて受光素子５に混入して発生する信号や、測距信号をサンプリングする時に発生する信号等が挙げられる。 The procedure for creating the first correction function will be described with reference to FIG. As shown in FIG. 2, a reflection plate 9 having a predetermined reflectance is arranged at a predetermined known distance that is known in advance, and the measurement emitted from the light emitting element 4 toward the reflection plate 9 is performed. Ranging light is transmitted, and ranging light reflected by the reflecting plate 9 is incident on the light receiving element 5 via a light amount adjusting member 10 capable of adjusting a transmitted light amount level of the ranging light. At this time, in the range where the AGC circuit 7 is inoperative and the influence of noise on the ranging signal can be ignored (the range of the ranging signal level is a predetermined value or less) , the light amount adjusting member 10 receives the light receiving element. The distance to the reflecting plate 9 is calculated while keeping the light level of the distance measuring light incident on 5 constant. Then, the difference between the calculated distance L1 to the reflecting plate 9 and the actual distance is written as a distance correction value ΔL 1 in the memory (not shown) of the control unit 2 together with the calculated distance L 1 . Next, in a state in which the light amount level of the distance measuring light incident on the light receiving element 5 is kept constant by the light amount adjusting member 10, the distance correction value ΔL 1 at each known distance is sequentially arranged at a plurality of known distances of the reflecting plate 9. And the calculation distance L 1 are written in the memory of the control unit 2. In the same manner, the first correction function f 1 indicating the distance correction value [Delta] L 1 for any calculated distance L 1 (L 1) is stored in the memory of the control unit 2. The above-mentioned “range in which the AGC circuit 7 is in an inoperative state” means a state in which the amplification factor of the amplifier 6 is not automatically adjusted by the AGC circuit 7, that is, a distance measurement signal at a predetermined amplification factor preset in the amplifier 6. Specifically, for example, the signal level of the distance measurement signal amplified by the amplifier 6 is set to a range that is equal to or lower than the saturation signal level of the amplifier 6. The above-mentioned “range in which the influence of noise on the ranging signal can be ignored” is, for example, a range in which the signal level of the ranging signal amplified by the amplifier 6 is 10% or more of the saturation signal level of the amplifier 6. Set to Examples of the “noise” include a signal generated when a signal for driving the light emitting element 4 is electrically coupled and mixed in the light receiving element 5, a signal generated when sampling a ranging signal, and the like. It is done.

上記の第二補正関数の作成手順を説明する。まず、第一補正関数の作成手順と同様に、所定の既知距離に反射板９を配置する。このとき、ＡＧＣ回路７が作動する範囲で、光量調整部材１０によって受光素子５に入射する測距光の光量レベルを一定に保ち、反射板９までの距離を演算する。そして、演算された反射板９までの演算距離Ｌ2と既知距離との差を距離補正値ΔＬ2として、本実施形態では受光素子５で受光される測距光の光量レベルと相関関係がある図１に示すＡＧＣ回路７の出力電圧ＶAと共に、制御部２のメモリに書き込んでいく。次いで、反射板９の距離を一定に保った状態で、光量調整部材１０の透過光量を変化させることで、ＡＧＣ回路７が作動する範囲で受光素子５に入射する測距光の光量レベルを順次変化させ、各光量レベルにおける距離補正値ΔＬ2と、ＡＧＣ回路７の出力電圧ＶAとを制御部２のメモリに書き込んでいく。以下同様にして、ＡＧＣ回路７の任意の出力電圧ＶAに対する距離補正値ΔＬ 2 を示す第二補正関数ｆ2（ＶA）が制御部２のメモリに記憶される。なお、上記の「ＡＧＣ回路が作動する範囲」とは、ＡＧＣ回路７によってアンプ６の増幅率が自動的に下げられた状態、すなわち、アンプ６に予め設定された所定の増幅率よりも小さい増幅率で測距信号が増幅される状態を意味し、具体的には、例えばアンプ６で増幅された測距信号の信号レベルが、アンプ６の飽和信号レベルよりも大きくなる範囲に設定される。 A procedure for creating the second correction function will be described. First, similarly to the procedure for creating the first correction function, the reflector 9 is arranged at a predetermined known distance. At this time, within the range in which the AGC circuit 7 operates, the light amount adjusting member 10 keeps the light amount level of the ranging light incident on the light receiving element 5 constant, and calculates the distance to the reflecting plate 9. The difference between the calculated distance L 2 to the reflecting plate 9 and the known distance is set as a distance correction value ΔL 2 , and in this embodiment, there is a correlation with the light amount level of the distance measuring light received by the light receiving element 5. Along with the output voltage V A of the AGC circuit 7 shown in FIG. Next, by changing the transmitted light amount of the light amount adjusting member 10 while keeping the distance of the reflecting plate 9 constant, the light level of the distance measuring light incident on the light receiving element 5 is sequentially changed within the range in which the AGC circuit 7 operates. The distance correction value ΔL 2 at each light quantity level and the output voltage V A of the AGC circuit 7 are written in the memory of the control unit 2. Similarly, the second correction function f 2 (V A ) indicating the distance correction value ΔL 2 for the arbitrary output voltage V A of the AGC circuit 7 is stored in the memory of the control unit 2. The “range in which the AGC circuit operates” refers to a state in which the amplification factor of the amplifier 6 is automatically lowered by the AGC circuit 7, that is, an amplification smaller than a predetermined amplification factor set in advance in the amplifier 6. This means that the distance measurement signal is amplified at a rate, and specifically, for example, the signal level of the distance measurement signal amplified by the amplifier 6 is set in a range that is larger than the saturation signal level of the amplifier 6.

上記の第三補正関数の作成手順を説明する。まず、第一補正関数の作成時と同様に、所定の既知距離に反射板９を配置する。このとき、ＡＧＣ回路７が非作動となる範囲であって且つ測距信号がノイズの影響を受ける状態で、光量調整部材１０によって受光素子５に入射する測距光の光量レベルを一定に保ち、反射板９までの距離を演算する。このとき得られた反射板９までの演算距離Ｌ3と既知距離との差を距離補正値ΔＬ3として、演算距離Ｌ3と共に制御部２のメモリに書き込んでいく。次いで、受光素子５に入射する測距光の光量レベルが一定になるように光量調整部材１０を調整しながら、反射板９を複数の既知距離に順次配置して、各既知距離における距離補正値ΔＬ3と、演算距離Ｌ3とを制御部２のメモリに書き込んでいく。以下同様にして、演算距離Ｌ3に対する距離補正値ΔＬ3を示す第三補正関数ｆ3（Ｌ3）が制御部２のメモリに記憶する。なお、上記の「測距信号がノイズの影響を受ける範囲」は、例えばアンプ６で増幅された測距信号の信号レベルが、アンプ６の飽和信号レベルの１０％未満となる範囲に設定される。 A procedure for creating the third correction function will be described. First, as in the creation of the first correction function, the reflector 9 is arranged at a predetermined known distance. At this time, in a state where the AGC circuit 7 is inoperative and the distance measurement signal is affected by noise, the light amount adjustment member 10 keeps the light amount level of the distance measurement light incident on the light receiving element 5 constant. The distance to the reflector 9 is calculated. The difference between the calculated distance L 3 and the known distance Prefecture of the reflective plate 9 obtained at this time as the distance correction value [Delta] L 3, and writes in the memory of the control unit 2 with the calculated distance L 3. Next, while adjusting the light amount adjusting member 10 so that the light amount level of the ranging light incident on the light receiving element 5 is constant, the reflector 9 is sequentially arranged at a plurality of known distances, and the distance correction value at each known distance. ΔL 3 and the calculation distance L 3 are written into the memory of the control unit 2. In the same manner, the calculated distance L third show the distance correction value [Delta] L 3 for 3 correction function f 3 (L 3) is stored in the memory of the control unit 2. The above-mentioned “range in which the distance measurement signal is affected by noise” is set to a range in which the signal level of the distance measurement signal amplified by the amplifier 6 is less than 10% of the saturation signal level of the amplifier 6, for example. .

上記のように各補正関数を作成して制御部２のメモリに記憶した後、反射板９と光量調整部材１０を測距光の光路上から取り外す。そして、被測定物８の距離測定時に、制御部２のメモリに記憶された３種の補正関数の中から受光素子５に受光される測距光の光量レベルに応じた補正関数が選択され、選択された補正関数に基づいて被測定物８までの演算距離が補正される。詳述すると、ＡＧＣ回路７が非作動状態であって且つ測距信号に対してノイズの影響が無視できる場合には、第一補正関数に基づいて被測定物８までの距離を補正し、ＡＧＣ回路７が作動状態にある場合には、第一補正関数および第二補正関数に基づいて被測定物８までの距離を補正し、ＡＧＣ回路７が非作動状態であって且つ測距信号がノイズの影響を受ける場合には、第三補正関数に基づいて被測定物８までの演算距離を補正する。   After each correction function is created and stored in the memory of the control unit 2 as described above, the reflector 9 and the light amount adjusting member 10 are removed from the optical path of the distance measuring light. Then, when measuring the distance of the object 8 to be measured, a correction function corresponding to the light level of the distance measuring light received by the light receiving element 5 is selected from the three types of correction functions stored in the memory of the control unit 2. Based on the selected correction function, the calculation distance to the DUT 8 is corrected. More specifically, when the AGC circuit 7 is inactive and the influence of noise on the distance measurement signal can be ignored, the distance to the object 8 to be measured is corrected based on the first correction function, and the AGC is performed. When the circuit 7 is in the operating state, the distance to the device under test 8 is corrected based on the first correction function and the second correction function, the AGC circuit 7 is in the inactive state, and the distance measurement signal is noise. Is affected, the calculation distance to the DUT 8 is corrected based on the third correction function.

具体的には、ＡＧＣ回路７が非作動状態であって且つ測距信号に対してノイズの影響が無視できる場合には、被測定物８までの距離Ｌは、補正前の被測定物８までの演算距離をＬ０とすると、上記の第一補正関数ｆ１（Ｌ１）を用いて以下の式１により求められる。 Specifically, when the AGC circuit 7 is inactive and the influence of noise on the distance measurement signal can be ignored, the distance L to the device under test 8 is up to the device under test 8 before correction. When the calculated distance and L 0, is determined by equation 1 below using the first correction function f 1 of the (L 1).

Ｌ＝Ｌ０−ｆ１（Ｌ０）………（１） L = L 0 −f 1 (L 0 ) (1)

また、ＡＧＣ回路７が作動状態にある場合には、まず、上記の第二補正関数ｆ２（ＶＡ）により、被測定物８までの仮の距離Ｌｘが以下の式２により求められる。なお、式中のＶＡ０は、被測定物８の距離測定時におけるＡＧＣ回路７の出力電圧である。 Further, when the AGC circuit 7 is in an operating state, first, a temporary distance L x to the device under test 8 is obtained from the second correction function f 2 (V A ) according to the following equation 2. V A0 in the equation is an output voltage of the AGC circuit 7 when measuring the distance of the DUT 8.

Ｌｘ＝Ｌ０−ｆ２（ＶＡ０）………（２） L x = L 0 −f 2 (V A0 ) (2)

次に、被測定物８までの距離Ｌが、式２により求められる仮の距離Ｌｘと、上記の第一補正関数ｆ１（Ｌ１）とを用いて、以下の式３により求められる。 Next, the distance L to the DUT 8 is obtained by the following equation 3 using the temporary distance L x obtained by the equation 2 and the first correction function f 1 (L 1 ).

Ｌ＝Ｌｘ−ｆ１（Ｌｘ）………（３） L = L x −f 1 (L x ) (3)

また、ＡＧＣ回路７が非作動状態であって且つ測距信号がノイズの影響を受ける場合には、被測定物８までの距離Ｌは、上記の第三補正関数ｆ３（Ｌ０）を用いて以下の式４により求められる。 When the AGC circuit 7 is inactive and the distance measurement signal is affected by noise, the distance L to the device under test 8 uses the third correction function f 3 (L 0 ) described above. The following equation 4 is obtained.

Ｌ＝Ｌ０−［（Ｖ０−Ｖｍａｘ）／（Ｖ１−Ｖｍａｘ）］・ｆ３（Ｌ０）……（４） L = L 0 − [(V 0 −V max ) / (V 1 −V max )] · f 3 (L 0 ) (4)

ここで、上記の式（４）中において、Ｖ０は被測定物８の距離測定時に被測定物８で反射して受光素子５に受光される測距光の光量レベル、Ｖ１は第三補正関数の作成時に反射板９で反射して受光素子５に受光される測距光の光量レベル、Ｖｍａｘは測距信号がノイズの影響の有無が現れる境界の光量レベルである。なお、例えばアンプ６で増幅された測距信号の信号レベルが、アンプ６の飽和信号レベルの１０％となるときに、受光素子５に受光される光量レベルが、Ｖｍａｘとして制御部２のメモリに予め記憶される。 Here, in the above formula (4), V 0 is the light amount level of the distance measuring light reflected by the measured object 8 and received by the light receiving element 5 when the distance of the measured object 8 is measured, and V 1 is the third level. The light amount level of the distance measuring light reflected by the reflecting plate 9 and received by the light receiving element 5 when the correction function is created, and V max is the light amount level at the boundary where the presence or absence of the influence of noise in the distance measurement signal appears. For example, when the signal level of the distance measurement signal amplified by the amplifier 6 is 10% of the saturation signal level of the amplifier 6, the light amount level received by the light receiving element 5 is V max. Stored in advance.

以上のように、第一実施形態に係る光学式測距方法によれば、被測定物の距離測定時に、ＡＧＣ回路７が非作動状態であって且つ測距信号に対してノイズの影響が無視できる場合には、第一補正関数に基づいて被測定物８までの演算距離が補正され、ＡＧＣ回路７が作動状態にある場合には、第一補正関数および第二補正関数に基づいて被測定物８までの演算距離が補正され、ＡＧＣ回路７が非作動状態であって且つ測距信号がノイズの影響を受ける場合には、第三補正関数に基づいて被測定物８までの演算距離が補正される。したがって、被測定物８までの演算距離に含まれる誤差は、受光素子５に受光される測距光の光量レベルに応じて、各補正関数によって的確に補正されるため、結果として被測定物８までの距離を高精度に測定することが可能となる。   As described above, according to the optical distance measuring method according to the first embodiment, when measuring the distance of the object to be measured, the AGC circuit 7 is inactive and the influence of noise on the distance measurement signal is ignored. If possible, the calculation distance to the device under test 8 is corrected based on the first correction function, and when the AGC circuit 7 is in the operating state, the device under test is measured based on the first correction function and the second correction function. When the calculation distance to the object 8 is corrected, the AGC circuit 7 is inactive, and the distance measurement signal is affected by noise, the calculation distance to the object 8 is calculated based on the third correction function. It is corrected. Therefore, the error included in the calculated distance to the object to be measured 8 is accurately corrected by each correction function according to the light amount level of the distance measuring light received by the light receiving element 5, and as a result, the object to be measured 8 Can be measured with high accuracy.

次に、本発明に係る第二実施形態を添付図面に基づいて説明する。なお、第二実施形態は、環境変化や経年変化によって被測定物８までの演算距離が変動する場合に、かかる環境変化や経年変化に応じて各補正関数を修正するために、基準反射部材を第一実施形態に更に設けたものである。   Next, a second embodiment according to the present invention will be described with reference to the accompanying drawings. In the second embodiment, when the calculation distance to the measurement object 8 fluctuates due to an environmental change or a secular change, the reference reflecting member is used to correct each correction function according to the environmental change or the secular change. This is further provided in the first embodiment.

図３は、第二実施形態に係る光学式測距方法を体現するための光学式測距装置を模式的に示す平面図である。同図に示すように、この光学式測距装置２０は、図１に示した光学式測距装置１のブロック図と同様の構成を含み、且つ、発光素子４から出射された測距光を例えば回転ミラー等で反射して周囲空間に走査するもので、走査領域のうち、所定の走査角度領域θに基準反射部材２１が配置固定されている。この基準反射部材２１は、本実施形態では、円周方向に沿って配置された第一基準反射部材２１ａと、第二基準反射部材２１ｂと、第三基準反射部材２１ｃとから構成されている。そして、測距光が円周方向の３６０度に走査される毎に、円周方向に沿って配置された各基準反射部材２１ａ、２１ｂ、２１ｃに順に測距光が送光され、各基準反射部材２１ａ、２１ｂ、２１ｃで反射した測距光が受光素子５で順次受光されるようになっている。この際、第一基準反射部材２１ａは、送光された測距光をＡＧＣ回路７が非作動となる範囲であって且つ測距信号に対してノイズの影響が無視できる範囲の光量レベルに調整して反射するようになっている。また、上記の第二基準反射部材２１ｂは、送光された測距光をＡＧＣ回路７が作動する範囲の光量レベルに調整して反射するようになっている。さらに、上記の第三基準反射部材２１ｃは、送光された測距光をＡＧＣ回路７が非作動となり且つ測距信号がノイズの影響を受ける範囲の光量レベルに調整して反射するようになっている。   FIG. 3 is a plan view schematically showing an optical distance measuring device for embodying the optical distance measuring method according to the second embodiment. As shown in the figure, the optical distance measuring device 20 includes the same configuration as the block diagram of the optical distance measuring device 1 shown in FIG. For example, it is reflected by a rotating mirror or the like to scan the surrounding space, and the reference reflecting member 21 is arranged and fixed in a predetermined scanning angle region θ in the scanning region. In the present embodiment, the reference reflecting member 21 includes a first reference reflecting member 21a, a second reference reflecting member 21b, and a third reference reflecting member 21c arranged along the circumferential direction. Then, every time the distance measuring light is scanned at 360 degrees in the circumferential direction, the distance measuring light is sequentially transmitted to the respective reference reflecting members 21a, 21b, and 21c arranged along the circumferential direction, and each reference reflection is performed. The distance measuring light reflected by the members 21a, 21b, and 21c is sequentially received by the light receiving element 5. At this time, the first reference reflection member 21a adjusts the transmitted distance measuring light to a light intensity level in a range where the AGC circuit 7 is inactive and the influence of noise on the distance measuring signal can be ignored. And it comes to reflect. Further, the second reference reflecting member 21b is configured to reflect the transmitted distance measuring light by adjusting the light amount level within a range in which the AGC circuit 7 operates. Further, the third reference reflecting member 21c reflects the transmitted distance measuring light after adjusting the light amount level within a range in which the AGC circuit 7 is not activated and the distance measuring signal is affected by noise. ing.

次に、上記のように構成された光学式測距装置２０の光学式測距方法を、基準反射部材２１を用いた上記の各補正関数の修正方法を中心に説明する。   Next, the optical distance measuring method of the optical distance measuring device 20 configured as described above will be described focusing on the correction method of each correction function using the reference reflecting member 21.

上記の第一補正関数の修正手順を説明する。まず、第一補正関数の作成時に、第一基準反射部材２１ａで反射した測距光を受光素子５で受光し、この受光した測距光に対応した測距信号に基づいて、第一基準反射部材２１ａまでの距離を演算し、このとき得られた演算距離Ｌ１０を制御部２のメモリに記憶する。また、同様にして、被測定物８の距離測定時に第一基準反射部材２１ａまでの距離を再度演算し、この演算距離をＬ１０’とする。そして、第一補正関数の作成時と、被測定物８の距離演算時とでの第一基準反射部材２１ａまでの演算距離の差を考慮して、第一補正関数ｆ１（Ｌ１）を、ｆ１（Ｌ１＋Ｌ１０’−Ｌ１０）に修正し、第一実施形形態で説明した被測定物８までの距離Ｌを求める式１を、以下の式５に修正する。 The procedure for correcting the first correction function will be described. First, when the first correction function is created, the distance measuring light reflected by the first reference reflecting member 21a is received by the light receiving element 5, and the first reference reflection is performed based on the distance measuring signal corresponding to the received distance measuring light. It calculates the distance to the member 21a, and stores the calculated distance L 10 obtained at this time in the memory of the control unit 2. Similarly, the distance to the first reference reflection member 21a is calculated again during the distance measurement of the object 8 to the calculated distance and L 10 '. Then, the first correction function f 1 (L 1 ) is calculated in consideration of the difference in the calculation distance to the first reference reflecting member 21a between the creation of the first correction function and the distance calculation of the object 8 to be measured. , F 1 (L 1 + L 10 ′ −L 10 ), and Equation 1 for obtaining the distance L to the DUT 8 described in the first embodiment is modified to Equation 5 below.

Ｌ＝Ｌ０−ｆ１（Ｌ０＋Ｌ１０’−Ｌ１０）………（５） L = L 0 −f 1 (L 0 + L 10 ′ −L 10 ) (5)

上記の第二補正関数の修正手順を説明する。第二補正関数の作成時に、第二基準反射部材２１ｂで反射した測距光を受光素子５で受光し、この第二基準反射部材２１ｂで反射した測距光を受光素子５で受光したときに得られるＡＧＣ回路７の出力電圧ＶＡ１を制御部２のメモリに記憶する。また、同様にして、被測定物８の距離測定時に、第二基準反射部材２１ｂで反射した測距光を受光素子５で受光したときに得られるＡＧＣ回路７の出力電圧ＶＡ２を求め、第二補正関数ｆ２（ＶＡ）を（ＶＡ２／ＶＡ１）・ｆ２（ＶＡ）に修正し、第一実施形態で説明した被測定物８までの仮の距離Ｌｘを求める式１を以下に示す式６に修正する。 A procedure for correcting the second correction function will be described. When the second correction function is created, the distance measuring light reflected by the second reference reflecting member 21b is received by the light receiving element 5, and the distance measuring light reflected by the second reference reflecting member 21b is received by the light receiving element 5. The obtained output voltage V A1 of the AGC circuit 7 is stored in the memory of the control unit 2. Similarly, an output voltage V A2 of the AGC circuit 7 obtained when the distance measuring light reflected by the second reference reflecting member 21b is received by the light receiving element 5 when measuring the distance of the object 8 to be measured is obtained. Formula 1 for correcting the two correction functions f 2 (V A ) to (V A2 / V A1 ) · f 2 (V A ) and obtaining the temporary distance L x to the device under test 8 described in the first embodiment. Is corrected to Equation 6 below.

Ｌｘ＝Ｌ０−（ＶＡ２／ＶＡ１）・ｆ２（ＶＡ０）………（６） L x = L 0 − (V A2 / V A1 ) · f 2 (V A0 ) (6)

そして、式６により求められる仮の距離Ｌｘと、修正された第一補正関数ｆ１（Ｌ１＋Ｌ１０’−Ｌ１０）とを用いて、被測定物８までの距離Ｌが以下の式７により求められる。 Then, using the provisional distance L x obtained by Expression 6 and the corrected first correction function f 1 (L 1 + L 10 ′ −L 10 ), the distance L to the measurement object 8 is expressed by the following expression. 7 is obtained.

Ｌ＝Ｌｘ−ｆ１（Ｌｘ＋Ｌ１０’−Ｌ１０）………（７） L = L x −f 1 (L x + L 10 ′ −L 10 ) (7)

上記の第三補正関数の修正手順を説明する。まず、第三補正関数の作成時に、反射板９で反射して受光素子５に受光される測距光の光量レベルＶ１と、このとき第三基準反射部材２１ｃで反射した測距光の光量レベルＶ２とを求め、制御部２のメモリに登録する。同様にして、被測定物８の距離測定時に、反射板９で反射して受光素子５に受光される測距光の光量レベルＶ０と、このとき第三基準反射部材２１ｃで反射した測距光の光量レベルＶ３とを求める。そして、第三補正関数ｆ３（Ｌ３）を含む［（Ｖ０−Ｖｍａｘ）／（Ｖ１−Ｖｍａｘ）］・ｆ３（Ｌ３）が、[（Ｖ０−Ｖｍａｘ）／（Ｖ１・Ｖ３／Ｖ２−Ｖｍａｘ）]・ｆ３（Ｌ３）に修正され、被測定物８までの距離Ｌが以下の式８により求められる。 A procedure for correcting the third correction function will be described. First, when creating the third correction function, the light level V 1 of the distance measuring light received by the light receiving element 5 is reflected by the reflection plate 9, the amount of the time distance measuring light reflected by the third reference reflection member 21c Level V 2 is obtained and registered in the memory of the control unit 2. Similarly, when the distance measurement of the object to be measured 8, the light level V 0 which distance measuring light reflected by the reflector 9 is received by the light receiving element 5, and reflected by the third reference reflection member 21c at this time ranging determining a light level V 3 of the light. Then, comprising a third correction function f 3 (L 3) [( V 0 -V max) / (V 1 -V max)] · f 3 (L 3) is, [(V 0 -V max) / ( V 1 · V 3 / V 2 −V max )] · f 3 (L 3 ), and the distance L to the DUT 8 is obtained by the following equation (8).

Ｌ＝Ｌ０−[（Ｖ０−Ｖｍａｘ）／（Ｖ１・Ｖ３／Ｖ２−Ｖｍａｘ）]・ｆ３（Ｌ０）………（８） L = L 0 − [(V 0 −V max ) / (V 1 · V 3 / V 2 −V max )] · f 3 (L 0 ) (8)

そして、被測定物８の距離測定時に、上記のようして修正された各補正関数を、第一実施形態と同様の条件で使い分け、被測定物８までの演算距離を補正する。   Then, when measuring the distance of the object 8 to be measured, the correction functions corrected as described above are properly used under the same conditions as in the first embodiment to correct the calculation distance to the object 8 to be measured.

以上のように、第二実施形態に係る光学式測距方法によれば、仮に、被測定物８までの演算距離が、環境変化や経年変化によって変動を来す場合であっても、所定距離に配置した第一基準反射部材２１ａ、第二基準反射部材２１ｂおよび第三基準反射部材２１ｃで反射して受光素子５で受光される測距光は、かかる環境変化や経年変化に応じた変化を示す。そのため、各基準反射部材２１ａ、２１ｂ、２１ｃで反射して受光素子５に受光されるそれぞれの測距光の変化量に基づいて、第一補正関数、第二補正関数および第三補正関数を修正すれば、環境変化や経年変化に依存しない、より高精度な距離測定を行うことが可能となる。   As described above, according to the optical distance measuring method according to the second embodiment, even if the calculation distance to the device under test 8 varies due to environmental changes or secular changes, the predetermined distance is used. The distance measuring light reflected by the first reference reflection member 21a, the second reference reflection member 21b and the third reference reflection member 21c and received by the light receiving element 5 is changed according to such environmental changes and aging changes. Show. Therefore, the first correction function, the second correction function, and the third correction function are corrected based on the amount of change in the distance measuring light reflected by the reference reflecting members 21a, 21b, and 21c and received by the light receiving element 5. This makes it possible to perform distance measurement with higher accuracy that does not depend on environmental changes or secular changes.

なお、本発明は、上記の実施形態に限定されることなく、以下に示すような種々の変形が可能である。   The present invention is not limited to the above-described embodiment, and various modifications as described below are possible.

例えば、上記の第一実施形態および第二実施形態では、被測定物８までの演算距離を補正する補正関数を、第一補正関数と、第二補正関数と、第三補正関数とから構成したものを説明したが、必要に応じて第三補正関数を省略してもよい。また、第三補正関数を省略した場合には、上記の第二実施形態で説明した基準反射部材２１を、第一基準反射部材２１ａと第二基準反射部材２１ｂとから構成し、第三基準反射部材２１ｃについては省略してもよい。また、第三補正関数は、第一補正関数や第二補正関数に比して、環境変化等の影響を受け難いため、上記の第二実施形態において、基準反射部材２１から第三基準反射部材２１ｃを省略してもよい。   For example, in the first embodiment and the second embodiment described above, the correction function for correcting the calculation distance to the DUT 8 is composed of the first correction function, the second correction function, and the third correction function. Although described above, the third correction function may be omitted if necessary. In addition, when the third correction function is omitted, the reference reflecting member 21 described in the second embodiment is configured by the first reference reflecting member 21a and the second reference reflecting member 21b, and the third reference reflecting member is formed. The member 21c may be omitted. In addition, since the third correction function is less susceptible to environmental changes and the like than the first correction function and the second correction function, in the second embodiment, the reference reflection member 21 to the third reference reflection member. 21c may be omitted.

また、上記の第二実施形態では、発光素子４から出射される測距光を周囲空間に走査する場合を例にとって、基準反射部材２１による各補正関数の修正方法を説明したが、測距光を走査せずに単一方向に送光するような場合であっても、基準反射部材２１による補正関数の修正方法を問題なく適用することができる。具体的には、例えば発光素子４から出射された測距光の一部をハーフミラー等によって分岐し、分岐した測距光を基準反射部材２１に送光すると共に、基準反射部材２１で反射した測距光を受光素子５で受光すれば、受光した測距光に基づいて同様に補正関数を修正することができる。   In the second embodiment, the method for correcting each correction function by the reference reflecting member 21 has been described by taking the distance measuring light emitted from the light emitting element 4 as an example for scanning the surrounding space. Even when the light is transmitted in a single direction without scanning, the correction function correcting method by the reference reflecting member 21 can be applied without any problem. Specifically, for example, part of the ranging light emitted from the light emitting element 4 is branched by a half mirror or the like, and the branched ranging light is transmitted to the reference reflecting member 21 and reflected by the reference reflecting member 21. If the distance measuring light is received by the light receiving element 5, the correction function can be similarly corrected based on the received distance measuring light.

さらに、本発明の光学式測距方法の測距方式は特に限定されるものではないが、例えば、発光素子４から出射される測距光をある一定の周波数で強度変調して、発光素子４から出射された測距光と、受光素子５で受光された測距光との位相差から被測定物８までの距離を求めるＡＭ（Ａｍｐｌｉｔｕｄｅ Ｍｏｄｕｌａｔｉｏｎ）方式や、発光素子４から出射される測距光を三角波の形で波長変調し、発光素子４から出射さらた測距光と、受光素子５で受光された測距光との干渉光の周波数信号から距離を求めるＦＭ（Ｆｒｅｑｕｅｎｃｙ Ｍｏｄｕｌａｔｉｏｎ）方式や、発光素子４から出射される測距光をパルス状に強度変調して、発光素子４から測距光を出射してから受光素子５で測距光を受光するまでの時間差から被測定物８までの距離を求めるＴＯＦ（Ｔｉｍｅ Ｏｆ Ｆｌｉｇｈｔ）方式などを問題なく適用することができる。   Further, the distance measuring method of the optical distance measuring method of the present invention is not particularly limited. For example, the distance measuring light emitted from the light emitting element 4 is intensity-modulated at a certain frequency, and the light emitting element 4 An AM (Amplitude Modulation) method for obtaining a distance to the DUT 8 based on a phase difference between the ranging light emitted from the light receiving element 5 and the ranging light received by the light receiving element 5; An FM (Frequency Modulation) method for obtaining a distance from a frequency signal of interference light between the ranging light emitted from the light emitting element 4 and the ranging light received by the light receiving element 5 by modulating the wavelength of the light in the form of a triangular wave The distance measuring light emitted from the light emitting element 4 is intensity-modulated in a pulse shape, and the object to be measured 8 is calculated from the time difference between the distance measuring light emitted from the light emitting element 4 and the light receiving element 5 receiving the distance measuring light. Distance to A TOF (Time Of Flight) method for obtaining separation can be applied without any problem.

第一実施形態に係る光学式測距方法を体現するための光学式測距装置を模式的に示すブロック図である。1 is a block diagram schematically showing an optical distance measuring device for embodying an optical distance measuring method according to a first embodiment. 補正関数の作成方法を説明する概念図である。It is a conceptual diagram explaining the preparation method of a correction function. 第二実施形態に係る光学式測距方法を体現するための光学式測距装置を模式的に示す平面図である。It is a top view which shows typically the optical distance measuring device for embodying the optical distance measuring method which concerns on 2nd embodiment.

符号の説明Explanation of symbols

１、２０ 光学式測距装置
２ 制御部
３ 発光素子駆動部
４ 発光素子
５ 受光素子
６ アンプ
７ ＡＧＣ回路
８ 被測定物
２１ａ 第一基準反射部材
２１ｂ 第二基準反射部材
２１ｃ 第三基準反射部材 DESCRIPTION OF SYMBOLS 1, 20 Optical distance measuring device 2 Control part 3 Light emitting element drive part 4 Light emitting element 5 Light receiving element 6 Amplifier 7 AGC circuit 8 Measured object 21a First reference reflection member 21b Second reference reflection member 21c Third reference reflection member

Claims (4)

発光素子から出射される測距光を被測定物に向けて送光し、前記被測定物で反射した測距光を受光素子で受光すると共に測距信号に変換し、前記受光素子で変換された測距信号の信号レベルに応じてＡＧＣ回路が作動して増幅率が自動的に下げられるアンプで前記測距信号を増幅し、前記アンプで増幅された前記測距信号に基づいて前記被測定物までの距離を演算する光学式測距方法において、
前記被測定物の距離測定前に、前記ＡＧＣ回路が非作動となる範囲で、前記受光素子に受光される測距光の光量レベルを一定に保ちながら複数の既知距離を測定し、各既知距離での演算距離に応じた距離補正値を示す第一補正関数を求めると共に、
前記ＡＧＣ回路が作動する範囲で、前記受光素子に受光される測距光の光量レベルを変化させながら単一の既知距離を測定し、各光量レベルでの演算距離に応じた距離補正値を示す第二補正関数を求め、
前記被測定物の距離測定時に、前記ＡＧＣ回路が非作動状態にある場合には、前記第一補正関数に基づいて前記被測定物までの演算距離を補正し、前記ＡＧＣ回路が作動状態にある場合には、前記第一補正関数および前記第二補正関数に基づいて前記被測定物までの演算距離を補正することを特徴とする光学式測距方法。 Ranging light emitted from the light emitting element is transmitted toward the object to be measured, and the ranging light reflected by the object to be measured is received by the light receiving element and converted into a distance measuring signal, which is converted by the light receiving element. The AGC circuit operates according to the signal level of the distance measurement signal, and the distance measurement signal is amplified by an amplifier whose amplification factor is automatically lowered, and the signal to be measured is based on the distance measurement signal amplified by the amplifier. In the optical ranging method that calculates the distance to an object,
Before measuring the distance of the object to be measured, a plurality of known distances are measured while keeping the light level of ranging light received by the light receiving element constant within a range in which the AGC circuit is inoperative. While obtaining a first correction function indicating a distance correction value according to the calculation distance in
To the extent that the AGC circuit is operated, the received by the light receiving element to measure the single known distance while changing the light quantity level of the measuring light, indicating the distance correction value according to the calculated distance for each light level Find the second correction function,
If the AGC circuit is in an inoperative state when measuring the distance of the object to be measured, the calculation distance to the object to be measured is corrected based on the first correction function, and the AGC circuit is in an operating state. In this case, the optical distance measuring method is characterized in that the calculation distance to the object to be measured is corrected based on the first correction function and the second correction function. 更に、第一基準反射部材と第二基準反射部材とをそれぞれ所定位置に配置して前記発光素子から出射される測距光の一部を各基準反射部材に対して送光し、
前記第一基準反射部材で測距光を前記ＡＧＣ回路が非作動となる範囲の光量レベルに調整して反射すると共に、前記受光素子で受光される前記第一基準反射部材で反射した測距光に基づいて前記第一補正関数を修正し、且つ、前記第二基準反射部材で測距光を前記ＡＧＣ回路が作動する範囲の光量レベルに調整して反射すると共に、前記受光素子で受光される前記第二基準反射部材で反射した測距光に基づいて前記第二補正関数を修正することを特徴とする請求項１に記載の光学式測距方法。 Further, the first reference reflection member and the second reference reflection member are arranged at predetermined positions, respectively, and a part of the ranging light emitted from the light emitting element is transmitted to each reference reflection member,
Ranging light reflected by the first reference reflecting member received by the light receiving element and reflected by the first reference reflecting member to reflect the distance measuring light to a light amount level in a range where the AGC circuit is not activated. The first correction function is modified based on the second reference reflecting member, and the distance measuring light is adjusted and reflected by the second reference reflecting member to a light amount level within a range in which the AGC circuit operates, and is received by the light receiving element. The optical distance measuring method according to claim 1, wherein the second correction function is corrected based on distance measuring light reflected by the second reference reflecting member. 更に、前記被測定物の距離測定前に、前記ＡＧＣ回路が非作動となる範囲であって且つ前記測距信号のレベルが所定値以下の範囲で、前記受光素子で受光される前記測距光の光量を一定に保ちながら複数の既知距離を測定し、各既知距離での演算距離に応じた距離補正量を示す第三補正関数を求め、
前記被測定物の距離測定時に、前記ＡＧＣ回路が非作動状態にあって且つ前記測距信号のレベルが前記所定値以下の場合には、前記第一補正関数に代えて前記第三補正関数に基づいて前記被測定物までの演算距離を補正することを特徴とする請求項１又は２に記載の光学式測距方法。 Further, the distance measuring light received by the light receiving element in a range where the AGC circuit is inoperative and the level of the distance measuring signal is a predetermined value or less before measuring the distance of the object to be measured. Measure a plurality of known distances while keeping the amount of light constant, and obtain a third correction function indicating a distance correction amount according to the calculation distance at each known distance,
When measuring the distance of the object to be measured, if the AGC circuit is in an inoperative state and the level of the distance measurement signal is not more than the predetermined value , the third correction function is used instead of the first correction function. The optical distance measuring method according to claim 1 or 2, wherein a calculation distance to the object to be measured is corrected based on the calculated distance. 更に、第三基準反射部材を所定位置に配置して前記発光素子から出射される測距光の一部を前記第三基準反射部材に対して送光し、
前記第三基準反射部材で測距光を前記ＡＧＣ回路が非作動となり且つ前記測距信号のレベルが前記所定値以下となる光量レベルに調整して反射すると共に、前記受光素子で受光される前記第三基準反射部材で反射した測距光に基づいて前記第三補正関数を修正することを特徴とする請求項３に記載の光学式測距方法。 Further, the third reference reflecting member is disposed at a predetermined position, and a part of the ranging light emitted from the light emitting element is transmitted to the third reference reflecting member,
The third reference reflecting member reflects the distance measuring light reflected by the light receiving element while the AGC circuit is deactivated and the level of the distance measuring signal is adjusted to a light level that is not more than the predetermined value. 4. The optical distance measuring method according to claim 3, wherein the third correction function is corrected based on distance measuring light reflected by the third reference reflecting member.
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