JPH0972736A - Range finder - Google Patents
Range finderInfo
- Publication number
- JPH0972736A JPH0972736A JP22550695A JP22550695A JPH0972736A JP H0972736 A JPH0972736 A JP H0972736A JP 22550695 A JP22550695 A JP 22550695A JP 22550695 A JP22550695 A JP 22550695A JP H0972736 A JPH0972736 A JP H0972736A
- Authority
- JP
- Japan
- Prior art keywords
- output
- ccd
- photoelectric conversion
- conversion element
- laser
- 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.)
- Pending
Links
Landscapes
- Length Measuring Devices By Optical Means (AREA)
- Measurement Of Optical Distance (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、レーザ源から移動
する被測定物に対してレーザ光を照射し、その反射光を
受光し電気信号に変換する蓄積型光電変換素子の出力信
号に基づいて被測定物までの距離を求める距離計に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is based on an output signal of a storage type photoelectric conversion element which irradiates a moving object to be measured with laser light, receives the reflected light, and converts the reflected light into an electric signal. The present invention relates to a range finder for obtaining a distance to an object to be measured.
【０００２】[0002]
【従来の技術】レーザダイオード（以下、「ＬＤ」と称
する）を利用して被測定物までの距離を測定する距離計
は公知である。図５はそのような距離計の原理的構成を
示すものである。図５に示す距離計は、ＬＤと電荷結合
素子（以下、「ＣＣＤ」と称する）を用いた三角測量方
式の距離計であって、光源たるＬＤ２から投射されたレ
ーザ光がレンズ４を通して被測定物６に照射される。被
測定物６で反射されたレーザ光がレンズ８を通してＣＣ
Ｄ１０で受光される。ここで、ＣＣＤ１０は蓄積型光電
変換素子として用いられているものである。ＣＣＤ１０
の出力電気信号は距離演算部１２に導かれ、ここで被測
定物６までの距離、すなわち距離計と被測定物６との間
の距離を周知の三角測量方式に従って算出する。2. Description of the Related Art A range finder for measuring a distance to an object to be measured using a laser diode (hereinafter referred to as "LD") is known. FIG. 5 shows the basic configuration of such a rangefinder. The rangefinder shown in FIG. 5 is a triangulation type rangefinder using an LD and a charge-coupled device (hereinafter, referred to as “CCD”). Laser light projected from the LD2, which is a light source, is measured through a lens 4. The object 6 is irradiated. The laser light reflected by the DUT 6 passes through the lens 8 and CC
The light is received at D10. Here, the CCD 10 is used as a storage type photoelectric conversion element. CCD10
Is output to the distance calculation unit 12, where the distance to the DUT 6, that is, the distance between the rangefinder and the DUT 6 is calculated according to a known triangulation method.
【０００３】この距離計においては、被測定物６の表面
性状や反射率の変化に伴い、ＣＣＤ１０の出力レベルが
変わりうる。この出力レベルの変化は距離の測定精度に
大きな悪影響を与える。そこで、この悪影響を回避し、
ＣＣＤ１０の出力信号がほぼ一定の大きさになるように
するために、ＣＣＤ１０の出力信号を入力するＬＤ制御
部１４を設け、これによりＬＤドライバ１６のゲインを
調節し、ＬＤ２の出力を加減する。In this range finder, the output level of the CCD 10 can change as the surface properties and reflectance of the DUT 6 change. This change in output level has a great adverse effect on the accuracy of distance measurement. Therefore, avoid this adverse effect,
In order to make the output signal of the CCD 10 substantially constant, an LD control unit 14 for inputting the output signal of the CCD 10 is provided, whereby the gain of the LD driver 16 is adjusted and the output of the LD 2 is adjusted.
【０００４】その場合、ＣＣＤ１０の電気出力をほぼ一
定にするのに具体的に次の３つの方式が存在する。 １）ＬＤ２の出力を連続レーザ光とし、その強度を、Ｃ
ＣＤ１０の出力電気信号の大小に応じて増減する方式
（図６）。たとえば、図示のごとく電気信号が大きすぎ
るときは、それを適切な大きさにするようにＬＤ２の出
力をレベルダウンする。In that case, the following three methods exist in order to make the electric output of the CCD 10 substantially constant. 1) The output of LD2 is continuous laser light, and its intensity is C
A method of increasing or decreasing according to the magnitude of the output electric signal of the CD 10 (FIG. 6). For example, when the electric signal is too large as shown in the figure, the output of the LD2 is leveled down so that the electric signal has an appropriate value.
【０００５】２）ＬＤ２の出力レーザ光をＣＣＤ１０の
シフトパルスに同期して周期を定め、その１周期内にお
けるオンオフ比を加減して平均値的に一定出力のレーザ
光出力とする方式（図７）。たとえば、図示のごとく電
気信号が大きすぎるときは、それを適切な大きさにする
ようにＬＤ２の個々のパルスのオンオフ比を小さくす
る。この場合、ＣＣＤ１０のシフトパルスの周期（信号
周期）とＬＤ２の出力レーザ光パルスの繰返し周期は１
対１に対応している。2) A method in which the output laser light of the LD 2 is synchronized with the shift pulse of the CCD 10 to determine a cycle, and the on / off ratio within one cycle is adjusted to obtain a laser light output with a constant average output (FIG. 7). ). For example, when the electric signal is too large as shown in the figure, the ON / OFF ratio of each pulse of the LD 2 is reduced so that the electric signal has an appropriate value. In this case, the shift pulse cycle (signal cycle) of the CCD 10 and the repetition cycle of the output laser light pulse of the LD 2 are 1
It corresponds to one-to-one.
【０００６】３）ＬＤ２の出力を一定強度の連続レーザ
光とし、ＣＣＤ１０への光入力量を、シャッタ機能を利
用して光学的にオンオフ制御する方式。3) A method in which the output of the LD 2 is a continuous laser beam having a constant intensity, and the amount of light input to the CCD 10 is optically turned on / off by using a shutter function.
【０００７】まず、１）の方式であるが、この方式はレ
ーザ光の出力強度により波長ずれやスポット光量分布が
変化してしまい、それらが測定精度に影響を与える。次
に、２）の方式は、図７からも推察しうるように、被測
定物６が移動体であると、レーザ光が被測定物６のたと
えば前半部にしか照射されないため、被測定物６全体の
平均化された距離を測定することができない。First of all, the method 1) is used. However, in this method, the wavelength shift and the spot light quantity distribution change depending on the output intensity of the laser light, which affects the measurement accuracy. Next, in the method of 2), as can be inferred from FIG. 7, when the DUT 6 is a moving body, the laser light is irradiated only to, for example, the front half of the DUT 6, so that the DUT is measured. 6 The averaged distance over 6 cannot be measured.
【０００８】最後に、３）の方式であるが、これはＣＣ
Ｄ１０への入力照射光をどの段階で調節するかの相違は
あるものの、結局２）の方式と同様の問題に帰結する。Finally, the method of 3), which is CC
Although there is a difference in which stage the input irradiation light to the D10 is adjusted, it eventually results in the same problem as the method of 2).
【０００９】[0009]
【発明が解決しようとする課題】本発明は、被測定物が
移動する場合であっても、正確な距離測定を行ないうる
距離計を提供することを目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to provide a range finder capable of performing accurate distance measurement even when an object to be measured moves.
【００１０】[0010]
【課題を解決するための手段】上記目的を達成するため
に本発明の距離計は、被測定物に対しほぼ一定強度のレ
ーザ光を照射するレーザ源と、被測定物からの反射レー
ザ光を受光し電気信号に変換する蓄積型光電変換素子
と、この蓄積型光電変換素子の出力電気信号の大きさが
ほぼ一定値となるようにレーザ源の出力レーザ光を蓄積
型光電変換素子の１信号周期より十分短い繰返し周期で
オンオフ制御する制御手段と、蓄積型光電変換素子の出
力電気信号に基づいて被測定物までの距離を算出する距
離演算手段とを備えたものである。In order to achieve the above object, a rangefinder according to the present invention comprises a laser source for irradiating an object to be measured with a laser beam having a substantially constant intensity, and a reflected laser beam from the object to be measured. A storage-type photoelectric conversion element that receives light and converts it into an electric signal, and one signal of the storage-type photoelectric conversion element that outputs the laser light output from the laser source so that the magnitude of the output electric signal of the storage-type photoelectric conversion element becomes almost constant. A control means for performing on / off control in a repetition cycle sufficiently shorter than the cycle and a distance calculation means for calculating the distance to the object to be measured based on the output electric signal of the storage photoelectric conversion element are provided.
【００１１】レーザ源の出力レーザ光強度をほぼ一定と
し、光電変換素子の１信号周期より十分短い繰返し周期
でオンオフ制御することにより、被測定物が移動体であ
ってもレーザ光がその全体に平均的に照射され、被測定
物の平均化された距離を求めることができる。By making the output laser light intensity of the laser source substantially constant and performing on / off control at a repetition cycle that is sufficiently shorter than one signal cycle of the photoelectric conversion element, the laser light is entirely distributed even if the object to be measured is a moving body. It is possible to obtain the average distance of the object to be measured which is irradiated on average.
【００１２】[0012]
（実施形態１）図１および図２を用いて本発明の一実施
形態を説明する。図１に示す距離計は、ＬＤと電荷結合
素子（以下、「ＣＣＤ」と称する）を用いた三角測量方
式の距離計であることは図５のものと同様であり、光源
たるＬＤ２から照射されたレーザ光がレンズ４を通して
被測定物６に照射され、被測定物６で反射されたレーザ
光がレンズ８を通してＣＣＤ１０で受光され、ここで電
気信号に変換される。ＣＣＤ１０の出力電気信号は距離
演算部１２に導かれ、ここで被測定物６までの距離、す
なわち距離計と被測定物６との間の距離が三角測量方式
に従って算出される。(Embodiment 1) An embodiment of the present invention will be described with reference to FIGS. The distance meter shown in FIG. 1 is the same as that of FIG. 5 in that it is a triangulation type distance meter using an LD and a charge-coupled device (hereinafter, referred to as “CCD”), and is illuminated by the light source LD2. The laser beam reflected by the DUT 6 is irradiated through the lens 4 to the DUT 6, and the laser beam reflected by the DUT 6 is received by the CCD 10 through the lens 8 and converted into an electric signal. The output electric signal of the CCD 10 is guided to the distance calculation unit 12, where the distance to the object 6 to be measured, that is, the distance between the rangefinder and the object 6 to be measured is calculated according to the triangulation method.
【００１３】さて、図２に示すように、この実施形態１
の特徴はＣＣＤ１０の出力信号を入力としてＬＤ制御部
１５によりＬＤドライバ１６を介して行なわれるＬＤ２
の制御態様にある。すなわち、ＬＤ２はその出力レーザ
光が一定ピーク値のもとにＣＣＤ１０のシフトパルスの
周期すなわち１走査周期より十分短い周期でオンオフ制
御しているのが特徴である。図には、ＬＤ２の出力光の
繰返し周期がＣＣＤ１０のシフトパルスのそれの１／６
に設定された（換言すれば、ＣＣＤ１０の１個のシフト
パルス周期内でＬＤ２の６個の出力光パルスが繰返され
る）例が示されている。Now, as shown in FIG. 2, this embodiment 1
The characteristic of the LD2 is that the LD control section 15 receives the output signal of the CCD 10 as an input and the LD2 is performed by the LD driver 16.
Control mode. That is, the LD 2 is characterized in that the output laser light is on / off controlled at a cycle sufficiently shorter than the cycle of the shift pulse of the CCD 10, that is, one scanning cycle, based on a constant peak value. In the figure, the repetition period of the output light of the LD 2 is ⅙ of that of the shift pulse of the CCD 10.
Is set (in other words, the six output light pulses of the LD2 are repeated within one shift pulse cycle of the CCD 10).
【００１４】図２の場合、ＣＣＤ１０の出力電気信号レ
ベルはＬＤ２の出力光パルスのオンオフ比の調整を通し
て行なわれ、たとえばＬＤ２の出力光パルスが大きすぎ
る場合、そのオンオフ比を小さくすることにより適切な
レベルに調節される。 （実施形態２）図３は図２の実施形態と同様にＣＣＤ１
０の１走査周期より十分短い周期でＬＤ２の出力レーザ
光をオンオフしているが、この実施形態の特徴は、ＣＣ
Ｄ１０の走査周期とＬＤ２のオンオフ周期の間で互いに
同期をとっていることにある。図２から認められるよう
に、前述の同期をとらなければＣＣＤ１０の走査周期に
よってＬＤ２の出力光量（図において、１周期内におけ
るオン部分の面積の加算値に相当）に差異を生じ、正確
な距離測定を不能にすることがある。この不都合は、図
３に示すように、ＣＣＤ１０の走査周期とＬＤ２のオン
オフ周期の間で互いに同期をとることにより回避するこ
とができる。 （実施形態３）ＣＣＤ１０（あるいは他の蓄積型光電変
換素子）が図４のＡに示すように、受光光量と電気信号
出力との間に非線形特性を持っている場合、この非線形
特性を補償すべくＬＤ２の１信号周期内でＬＤ２のオン
オフ制御を、受光光量に対し電気信号出力の大きい（図
において特性線が立っている）領域Ｒ１では相対的にオ
ンオフ比を小さく、受光光量に対し電気信号出力の小さ
い（特性線が寝ている）領域Ｒ３では相対的にオンオフ
比を大きく、両者の中間の領域Ｒ２では中間のオンオフ
比とするように重み付け制御とすることにより、被測定
物６が移動体である場合であっても移動部分の各反射光
の影響を平均化することができる。In the case of FIG. 2, the output electric signal level of the CCD 10 is controlled by adjusting the on / off ratio of the output light pulse of the LD2. For example, when the output light pulse of the LD2 is too large, the on / off ratio of the output light pulse is appropriately reduced. Adjusted to the level. (Embodiment 2) FIG. 3 shows a CCD 1 similar to the embodiment of FIG.
The output laser light of the LD 2 is turned on and off at a cycle sufficiently shorter than one scan cycle of 0. The feature of this embodiment is that CC
The scanning cycle of D10 and the on / off cycle of LD2 are synchronized with each other. As can be seen from FIG. 2, if the above-mentioned synchronization is not taken, the output light amount of the LD 2 (corresponding to the added value of the ON portion area within one period in the figure) varies depending on the scanning period of the CCD 10, and the accurate distance is obtained. May disable measurements. This inconvenience can be avoided by synchronizing the scanning cycle of the CCD 10 and the ON / OFF cycle of the LD 2 with each other, as shown in FIG. (Embodiment 3) When the CCD 10 (or other storage type photoelectric conversion element) has a non-linear characteristic between the amount of received light and the electric signal output as shown in A of FIG. 4, this non-linear characteristic is compensated. Therefore, the ON / OFF control of the LD2 is performed within one signal cycle of the LD2, and the ON / OFF ratio is relatively small in the region R1 where the electric signal output is large with respect to the received light amount (the characteristic line stands in the figure), and the electric signal with respect to the received light amount The object 6 moves by performing weighting control so that the on / off ratio is relatively large in the region R3 where the output is small (the characteristic line is lying) and the on / off ratio is intermediate in the region R2 between the two. Even in the case of the body, it is possible to average the influence of each reflected light of the moving part.
【００１５】[0015]
【発明の効果】本発明によれば、ＣＣＤのような蓄積型
光電変換素子の１信号周期より十分短い周期でＬＤの光
出力をオンオフ制御することにより、たとえ被測定物が
移動する場合であっても、その移動する全部分の平均化
された距離を的確に求めることができる。According to the present invention, even if the object to be measured moves by controlling the optical output of the LD on and off at a cycle sufficiently shorter than one signal cycle of a storage type photoelectric conversion element such as a CCD. However, the averaged distances of all the moving parts can be accurately obtained.
【図１】本発明による距離計の機器配置を示す図。FIG. 1 is a diagram showing a device layout of a distance meter according to the present invention.
【図２】図１の距離計の第１の実施態様を示す信号波形
図。FIG. 2 is a signal waveform diagram showing a first embodiment of the range finder of FIG.
【図３】図１の距離計の第２の実施態様を示す信号波形
図。FIG. 3 is a signal waveform diagram showing a second embodiment of the range finder of FIG.
【図４】図１の距離計の第３の実施態様を示す信号波形
図。4 is a signal waveform diagram showing a third embodiment of the distance meter of FIG.
【図５】公知の距離計の機器配置を示す図。FIG. 5 is a diagram showing a device layout of a known rangefinder.
【図６】図５の距離計の第１の具体例を示す信号波形
図。FIG. 6 is a signal waveform diagram showing a first specific example of the distance meter of FIG.
【図７】図５の距離計の第２の具体例を示す信号波形
図。FIG. 7 is a signal waveform diagram showing a second specific example of the distance meter of FIG.
２ レーザダイオード（ＬＤ） ４ レンズ ６ 被測定物 ８ レンズ １０ 電荷結合素子（ＣＣＤ） １２ 距離演算部 １５ レーザダイオード（ＬＤ）制御部 １６ レーザダイオード（ＬＤ）ドライバ 2 Laser diode (LD) 4 Lens 6 Object to be measured 8 Lens 10 Charge coupled device (CCD) 12 Distance calculation unit 15 Laser diode (LD) control unit 16 Laser diode (LD) driver
Claims (3)
照射するレーザ源と、前記被測定物からの反射レーザ光
を受光し電気信号に変換する蓄積型光電変換素子と、こ
の蓄積型光電変換素子の出力電気信号の大きさがほぼ一
定値となるように前記レーザ源の出力レーザ光を前記蓄
積型光電変換素子の１信号周期より十分短い繰返し周期
でオンオフ制御する制御手段と、前記蓄積型光電変換素
子の出力電気信号に基づいて前記被測定物までの距離を
算出する距離演算手段とを備えた距離計。1. A laser source for irradiating an object to be measured with a laser beam having a substantially constant intensity, a storage type photoelectric conversion element for receiving reflected laser light from the object to be measured and converting it into an electric signal, and the storage type. Control means for on / off controlling the output laser light of the laser source at a repetition cycle sufficiently shorter than one signal cycle of the storage photoelectric conversion element so that the magnitude of the output electric signal of the photoelectric conversion element becomes a substantially constant value; A distance meter including a distance calculation unit that calculates a distance to the object to be measured based on an output electric signal of the storage photoelectric conversion element.
ザ光が前記蓄積型光電変換素子の１信号周期に同期する
ように前記レーザ源を制御する請求項１記載の距離計。2. The rangefinder according to claim 1, wherein the control means controls the laser source so that the output laser beam of the laser source is synchronized with one signal period of the storage photoelectric conversion element.
の１信号周期内における前記レーザ源の複数の出力レー
ザ光の個々のオンオフ比を、前記蓄積型光電変換素子の
受光光量に対する電気信号出力の非線形特性を補償する
ように重み付け制御する請求項１記載の距離計。3. The control means sets an individual on / off ratio of a plurality of output laser beams of the laser source in one signal period of the storage type photoelectric conversion element to an electric signal with respect to a received light amount of the storage type photoelectric conversion element. The rangefinder according to claim 1, wherein weighting control is performed so as to compensate for the non-linear characteristic of the output.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22550695A JPH0972736A (en) | 1995-09-01 | 1995-09-01 | Range finder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22550695A JPH0972736A (en) | 1995-09-01 | 1995-09-01 | Range finder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0972736A true JPH0972736A (en) | 1997-03-18 |
Family
ID=16830393
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22550695A Pending JPH0972736A (en) | 1995-09-01 | 1995-09-01 | Range finder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0972736A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010054373A (en) * | 2008-08-28 | 2010-03-11 | Nissan Motor Co Ltd | Apparatus and method for extracting irradiation light |
| WO2013129387A1 (en) * | 2012-03-01 | 2013-09-06 | 日産自動車株式会社 | Range finding device and range finding method |
-
1995
- 1995-09-01 JP JP22550695A patent/JPH0972736A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010054373A (en) * | 2008-08-28 | 2010-03-11 | Nissan Motor Co Ltd | Apparatus and method for extracting irradiation light |
| WO2013129387A1 (en) * | 2012-03-01 | 2013-09-06 | 日産自動車株式会社 | Range finding device and range finding method |
| JPWO2013129387A1 (en) * | 2012-03-01 | 2015-07-30 | 日産自動車株式会社 | Distance measuring device and distance measuring method |
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