JP2008180593A - Distance change observation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve observation having high reliability by having easy device setting, continuing observation without influencing change of an observation environment by a simple composition, and preventing erroneous measurement of a distance in a distance change observation device using an optical beam. <P>SOLUTION: The distance change observation device 1 includes: a projection part 2 for projecting the optical beam used for distance measurement; a projection optical part 3 for regarding the optical beam L0 from the projection part 2 as illumination light L1 adjusting a widening angle θ; a light receiving part 4 for outputting a light receiving signal by receiving reflection light L2 from a target TG reflecting the illumination light L1 from the projection optical part 3; and a distance calculation part 5 for calculating a distance D from the projection part 2 to the target TG as the distance D between two points P1, P2 based on an elapse time from a projection time of the optical beam L0 by the projection part 2 to a light receiving time by the light receiving part 4. The light receiving part 4 outputs the light receiving signal for determining the light receiving time if the elapse time from the projection time is in a previously set time range. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a distance change observation apparatus that observes a change in distance by periodically measuring a distance between two points, a fixed point and a moving point, based on a round trip time of a light beam.

  In general, the distance to an object that reflects a light beam by light projection and reception that can determine the light projection time and the light reception time is determined. In such distance measurement, as shown in FIG. 18 (a), relative distance measurement for knowing the positional change of the target TG determined as a specific object in advance, and as shown in FIG. 18 (b), There are absolute distance measurements for tracking and searching unspecified objects.

  In the case of the former relative distance measurement, it is possible to know the positional change of the target TG by measuring the distance D to the target TG with the measuring device 9 installed at a fixed point and periodically observing the distance change ΔD. it can. Such an apparatus can be applied to, for example, prediction of occurrence of a landslide on a slope. In this case, a change in distance to the same target TG is regularly observed, and it is important to know a relative change in distance from a distance at a certain measurement time rather than an absolute distance to the target TG. The amount of movement of the target TG is usually within a range that is expected to some extent.

  In the case of the latter absolute distance measurement, for example, the measuring device 9 is installed in the vehicle, and the obstacle D is detected by detecting the obstacle by measuring the distance D to the object M such as a moving obstacle or a fixed obstacle ahead. It can be applied to. In this case, measurement is usually performed because the distance to the object M is not known, and it is important to know the absolute distance to the object M in order to prevent collision.

  By the way, as a distance change observation apparatus based on the relative distance measurement corresponding to the above-mentioned former, a laser scanner is used for the measurement apparatus 9 as shown in FIG. When irradiating the target TG with the irradiation light L1 to be scanned and receiving the reflected light L2 from the target TG and observing the distance D, or as shown in FIG. 19B, the irradiation light L1 having a small spread from the measuring device 9 Is projected toward the target TG, the reflected light L2 from the target TG is received, and the distance D is observed.

  In the case of the laser scanner of FIG. 19A, a driving unit and a mirror connected to the projection unit are mounted on the light projecting unit, and a laser beam with a small divergence angle is scanned left and right or up and down, and the distance between each point on the target TG. Must be measured sequentially. However, a driving unit and control software for scanning the laser beam are necessary, and there is a problem that the price is high, the apparatus size is large, and the weight is heavy. In addition, it is difficult to ensure reliability in environments where the drive unit is hot, cold, or wet. Especially, it is not suitable for long-term use outdoors, and it also takes time to measure each time because it scans. .

  In the case of FIG. 19B, there is no problem in the normal use state as shown in FIG. 20A, but as shown in FIGS. 20B and 20C, the measuring device 9 and the target If the ground at the fixed point where the TG is installed is loosened, the installation of the measuring device 9 is incomplete, or the measuring device 9 or the target TG is tilted or rotated, the irradiation light L1 is detached from the target TG. This makes it impossible to continue observation of distance changes.

As a means for solving the above-described problem, a measuring apparatus including a distance measuring light divergence angle adjusting device that adjusts the divergence angle of the illuminating light L1 is known to facilitate the application of the illuminating light L1 to the target TG. (For example, refer to Patent Document 1).
JP-A-10-19561

  However, in the measurement apparatus for distance change observation as shown in Patent Document 1 described above, the reflected light from the light reflecting object around the target TG or between the measurement apparatus and the target TG is not reflected in the original. There is a problem that the distance is erroneously recognized as the reflected light from the target TG and the distance is erroneously measured.

  The present invention solves the above-mentioned problems, and with a simple configuration, the apparatus can be easily set up and observation can be continued without being affected by changes in the observation environment. An object of the present invention is to provide a distance change observation apparatus using a light beam that can realize high observation.

  In order to achieve the above object, the invention according to claim 1 is a distance for observing a change in the distance by periodically measuring the distance between the fixed point and the moving point based on the round trip time of the light beam. In the change observing apparatus, a light projecting unit that projects a light beam used for the distance measurement, a light projecting optical unit that uses the light beam from the light projecting unit as irradiation light with a spread angle adjusted, and the light projecting optical unit A light receiving unit that receives reflected light from a target that reflects the irradiation light from the light source and outputs a light reception signal, and an elapsed time from the light projection time of the light beam by the light projecting unit to the light reception time by the light receiving unit A distance calculation unit that calculates a distance from the light projecting unit to the target as a distance between the two points, and the light receiving unit is within a preset time range from the light projection time. Only when the light reception time is And it outputs a light reception signal to a constant.

  According to a second aspect of the present invention, in the distance change observation device according to the first aspect, when the light receiving unit receives a plurality of reflected lights within the preset time range, a light reception amount is the maximum among them. Is selected as true reflected light, and a light receiving signal corresponding to the reflected light is output.

  According to a third aspect of the present invention, in the distance change observation device according to the first aspect, when the light receiving unit receives a plurality of reflected lights within the preset time range, the light receiving unit first receives them. The reflected light is selected as true reflected light, and a light receiving signal corresponding to the reflected light is output.

  According to a fourth aspect of the present invention, in the distance change observation device according to the first aspect, the light receiving unit receives only light in a specific polarization state and outputs a light reception signal.

  According to a fifth aspect of the present invention, in the distance change observation device according to the first aspect, the projection optical unit includes an external adjustment unit for adjusting the light beam divergence angle from the outside of the apparatus main body. It is.

  According to a sixth aspect of the present invention, in the distance change observation device according to the first or fifth aspect, the light receiving unit includes an external output unit that displays or reports information on the amount of received light to the outside.

  According to the first aspect of the present invention, since the divergence angle of the irradiation light can be increased by the light projecting optical unit, the observation can be continued even if the direction of the irradiation light slightly deviates from the initial installation, and the direction of the irradiation light It is possible to observe with a rough setting without strictly adjusting to the target. Furthermore, since the light receiving time is determined only when the elapsed time from the light projecting time is within a preset time range in the light receiving unit, the reflected light received outside the preset time range is changed to other than the target. It can be excluded as reflected light from structures, etc., and it is possible to realize a highly reliable observation by preventing erroneous measurement of distance.

  According to the second aspect of the present invention, by making the reflectance of the target higher than that of the surrounding object, it is possible to prevent erroneous measurement by erroneously recognizing the reflected light by the light beam irradiated to the object around the target. Highly reliable observation can be realized.

  According to the invention of claim 3, it is possible to prevent erroneous measurement by erroneously recognizing reflected light from an object behind the target, and to realize highly reliable observation.

  According to the fourth aspect of the present invention, the reflected light from the target is in a specific polarization state, so that the reflected light from an object other than the target can be efficiently and reliably excluded, and an error in distance can be obtained. Highly reliable observation can be realized by preventing measurement.

  According to the fifth aspect of the invention, when setting the distance change observation device, first, the light beam spread angle is increased to roughly adjust the light projection direction, and then the spread angle is decreased to perform thorough adjustment. Therefore, it is possible to easily adjust the direction of the light beam in the target direction.

  According to the sixth aspect of the invention, since the irradiation direction of the light beam can be adjusted while reliably recognizing the setting state numerically or perceptually, the initial setting operation of the distance change observation device can be easily performed.

  Hereinafter, a distance change observation apparatus according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
1 shows a block configuration of the distance change observation apparatus according to the first embodiment, FIG. 2 shows a usage state of the distance change observation apparatus, FIG. 3 (a) shows a time chart of irradiation light irradiation, and FIG. (B) shows a time chart for receiving reflected light, FIGS. 4 (a) and 4 (b) show time charts for other irradiated light and reflected light, and FIGS. 5 and 6 show the principle of distance measurement.

  As shown in FIGS. 1 and 2, the distance change observation device 1 periodically measures the distance D between two points, ie, the fixed point P1 and the moving point P2, based on the round trip time of the light beam. A device for observing the change ΔD, a light projecting unit 2 that projects a light beam used for distance measurement, and a light projecting optical unit that converts the light beam L0 from the light projecting unit 2 into an irradiation light L1 with a spread angle θ adjusted. 3, the light receiving unit 4 that receives the reflected light L 2 from the target TG that reflects the irradiation light L 1 from the light projecting optical unit 3 and outputs a light reception signal, and the light projecting time of the light beam L 0 by the light projecting unit 2. A distance calculation unit 5 that calculates a distance D from the light projecting unit 2 to the target TG as a distance D between the two points P1 and P2 based on an elapsed time up to a light reception time by the light receiving unit 4;

  The light projecting optical unit 3 and the light receiving unit 4 described above are arranged side by side in the same housing 10, but the configuration is not limited to this, and the light projecting optical unit 3 and the light receiving unit 4 include The configuration may be such that they are on the same axis, they are not adjacent to each other, are spaced apart from each other, or are arranged in separate housings.

  As described above, instead of installing the distance change observation device 1 at the fixed point P1 and installing the target TG at the movement point P2, the distance change observation device 1 is installed at the movement point P2 and the target TG is installed at the fixed point P1. You may make it do.

  The target TG is disposed so that the light projecting optical unit 3 of the distance change observation device 1 and the reflection surface of the target TG face each other, and the irradiation light L1 reliably strikes the reflection surface of the target TG. The target TG preferably reflects the irradiation light L1 and has a high light reflectance. As the target TG, a white wooden board, an iron board, a plastic board, or the like can be used. In order to efficiently reflect the irradiation light L1 and return the reflected light L2 to the light receiving unit 4 side, it is preferable to arrange a retroreflective element, a retroreflective sheet, or the like as a reflective surface of the target TG.

  The size of the reflection surface of the target TG is about 1 cm square to 1 m square. This size is determined in consideration of the distance D. The reflection surface is not limited to a square, and may be a rectangle, other polygons, a circle, or an irregular shape. The shape is preferably a plane as much as possible, but is not necessarily a plane.

  As shown in FIG. 3A, the irradiation light L1 projected from the light projecting unit 2 and having the divergence angle θ by the light projecting optical unit 3 has a pulse shape with a light emission time δt of 1 μs or less (δt ≦ 1 μs). The light having the waveform p0 is light emission interval Δt of 1 μs or more (Δt> 1 μs). The reflected light L2 reflected by the pulsed irradiation light L1 when it hits the target TG is light having a pulsed waveform p similar to that of the irradiation light L1, as shown in FIG. 3B.

  The projected light beam L0, and hence the irradiation light L1 and the reflected light L2, do not have to be pulsed light separated from each other as described above. As shown in FIGS. 4 (a) and 4 (b), It may be continuous light in which the amount of light G repeats intensity under a constant (regular) pattern. At that time, by extracting at least characteristic parts of the intensity pattern (strong and weak peak positions, points exceeding a certain threshold, rising and falling slopes, etc.), the light projection time and the light reception time are obtained. Must be uniquely identified.

  The light beam projected from the light projecting unit 2 is not limited to visible light, but infrared light or ultraviolet light may be used. The light emitting device in the light projecting unit 2 may be any device that emits light. For example, a laser diode (LD), a light emitting diode (LED), a light bulb, or the like can be used.

  As shown in FIGS. 5 and 6, the distance calculation unit 5 performs an elapsed time from the light projection time t1 of the light beam L0 by the light projecting unit 2 to the light reception time t2 by the light receiving unit 4 (round trip time between points P1 and P2). ) To calculate the distance D from the light projecting unit 2 to the target TG. The light projecting time is determined by causing the light projecting unit 2 to output a light projecting signal, or causing the light receiving unit 4 to receive light demultiplexed from the light beam L0 or the irradiation light L1 and outputting a light receiving signal. The projection time may be determined.

  According to the distance change observation device 1 having the above-described configuration, the light projecting optical unit 3 can increase the spread angle θ of the irradiation light L1, so that the observation is performed even if the direction of the irradiation light L1 slightly deviates from the initial installation. The observation can be started with a rough setting even if the direction of the irradiation light L1 is not strictly aligned with the target.

(Second Embodiment)
FIGS. 7A, 7B, 7C, and 7D show the adjustment of the divergence angle of the light beam in the distance change observation apparatus according to the second embodiment. In the present embodiment, details of the light projecting optical unit 3 in the distance change observation device 1 of the first embodiment will be described. The light projecting optical unit 3 shown in FIG. 7A uses the concave lens 31 and the convex lens 32 to convert the light beam L0 from the light projecting unit 2 into irradiation light L1 having a spread angle θ. The divergence angle θ can be adjusted by changing the distance x between the concave lens 31 and the convex lens 32.

  The light projecting optical unit 3 shown in FIG. 7B includes a convex lens 33 whose position is variable in the optical axis direction between the concave lens 31 and the convex lens 32 in FIG. 7A described above. The spread angle θ of the irradiation light L1 can be adjusted by the positional change Δx of the convex lens 33.

  The light projecting optical unit 3 shown in FIG. 7C uses the convex mirror 34 and the concave mirror 35 to convert the light beam L0 into the irradiation light L1 having a divergence angle θ. The divergence angle θ can be adjusted by changing the distance x between the convex mirror 34 and the concave mirror 35.

  Note that the spread angle of the irradiation light L1 is not limited to a combination of a single concave lens and a convex lens, but a combination of a plurality of lenses, a combination of curved mirrors, or a combination of a plurality of lenses and mirrors. A configuration in which θ is adjusted may be used.

  Further, in the case of a device that projects a light beam L0 (divergent light) with the light source itself of the light projecting unit 2 spreading, the light projecting optical unit 3 configured to adjust the spread may be used. Also in this case, not only a configuration using a lens but also a configuration using a curved mirror as described below may be used.

  When the light beam L0 from the light projecting unit 2 is diverging light, the light projecting optical unit 3 shown in FIG. 7D uses a single convex lens 32 to narrow the divergence angle of the light beam L0 to a predetermined value. The divergence angle θ is used. The spread angle θ of the irradiation light L1 can be adjusted by the positional change Δx of the convex lens 32.

(Third embodiment)
FIGS. 8A, 8B, and 8C show a usage state of the distance change observation apparatus according to the third embodiment. In the present embodiment, the distance change observation device 1 of the first and second embodiments can continue observation even if the direction of the irradiation light L1 is slightly deviated from the initial installation, and the direction of the irradiation light L1 is strictly targeted. It explains that observation can be started with a rough setting without matching.

  FIG. 8A shows a state in which distance change observation is normally performed using the irradiation light L1 having a divergence angle θ in the vertical direction. FIG. 8B shows that the distance change observation can be continued even though the distance change observation device 1 is tilted forward by using the irradiation light L1 having the divergence angle θ in the vertical direction. Indicates. FIG. 8C shows a state in which the target TG is irradiated with the irradiation light L1 having a spread angle θ in the horizontal plane. In this figure, since the target TG is within the spread angle θ of the irradiation light L1, observation is possible with a rough setting even though the distance change observation device 1 and the target TG are not facing each other. Indicates that

  As described above, the spreading direction of the irradiation light L1 is not limited to the vertical direction, but can be the vertical spreading or the horizontal spreading. Irradiation light L1 that spreads while the cross section in the direction orthogonal to the optical axis remains substantially circular may be used. Further, the cross-section is not necessarily circular, and may be elliptical or flattened in the vertical or horizontal direction.

  The angle range for adjusting the spread angle θ of the irradiation light L1 may be about the same as the angle range in which the distance change observation device 1 is inclined. For example, when there is a possibility that the distance change observation apparatus 1 is tilted by 1 ° after the installation, the light beam can be prevented from coming off the target TG by setting the spread angle θ to 1 °.

  In the case of installation in a normal environment, the inclination of the distance change observation device 1 does not become 5 ° even if it is large. Therefore, the adjustment range of the spread angle θ should be 0 ° to 5 °. However, since the angle range may be exceeded depending on the stability of the installation location, it is not necessarily limited to this range.

  When the irradiation light L1 does not spread, if the distance change observation device 1 is tilted after installation, the irradiation light L1 does not hit the target TG, and observation cannot be performed. If the irradiation light L1 has a divergence angle θ, even when the distance change observation device 1 is tilted, the irradiation light L1 does not deviate from the target TG, and observation can be continued.

  In the case of the irradiation light L1 having no spread, it is difficult to adjust the orientation of the main body so that the irradiation light L1 strikes the target TG, particularly when the target TG is far away. This is because, as the target TG becomes farther away, the amount of movement of the spot position of the irradiation light L1 becomes larger depending on the amount of change in the direction of the main body, so that a fine angle adjustment is required to align the spot with the target TG. It is. However, if the illuminating light L1 has a divergence angle as in the distance change observation device 1, the range that the illuminating light L1 strikes increases, so that the main body is roughly oriented without requiring fine adjustment. Only, the irradiation light L1 can hit the target TG, and the apparatus can be easily set.

(Fourth embodiment)
FIG. 9 shows a usage state of the distance change observation apparatus according to the fourth embodiment, and FIG. 10 shows a time chart of reflected light reception. In the present embodiment, a process of outputting a received light signal performed by the light receiving unit 4 of the distance change observation device 1 in the first to third embodiments described above will be described.

  Since the irradiation light L1 projected by the distance change observation device 1 has a divergence angle, as shown in FIG. 10, the irradiation light L1 hits an object A, B, etc. other than the target TG, and is reflected therefrom. Lights La and Lb may be received. When the light receiving unit 4 receives these reflected lights La and Lb and outputs a light reception signal, the position of the target TG cannot be observed correctly.

  In the above case, if the amount of movement of the target TG, and therefore the position of the target TG, can be predicted to some extent, it is effective to limit the timing of receiving light by the light receiving unit 4 within a preset time. For example, as illustrated in FIG. 10, the light receiving unit 4 outputs a light reception signal only during a time range w from time t <b> 21 when time s has elapsed from light projection time t <b> 1. That is, the light receiving unit 4 does not output a light reception signal between the times t1 and t21 and after the time t22. With this setting, the light reception signals a and b based on the reflected light La and Lb are not output, and only the light reception signal p based on the reflected light L2 from the target TG is output to the distance calculation unit 5.

  The preset time s and time range w depend on the amount of movement of the target TG. For example, when there is a possibility that the movement amount of the target TG is unilaterally moved backward from the initial installation position by a maximum of 1 m, the time range w may be set to w = 7 ns (nanoseconds).

  Actually, the setting is not limited to the above-described way of thinking, and the setting may be performed with a margin before and after. The time s and the time range w need not be set at the time of initial setting of the distance change observation device 1, and may be set when the time s and the time range w need to be set.

  As described above, the light receiving unit 4 outputs a light reception signal for determining the light reception time t2 only when the elapsed time from the light projection time t1 falls within the preset time range t21 to t22. Reflected light received outside the preset time range w (w = t22−t21) can be excluded as reflected light from an object other than the target TG, thereby preventing erroneous measurement of distance and ensuring reliability. High observation can be realized.

(Fifth embodiment)
FIG. 11 shows a usage state of the distance change observation apparatus according to the fifth embodiment, and FIG. 12 shows a time chart of reflected light reception. In the present embodiment, a process for further increasing the SN ratio is added to the process performed by the light receiving unit 4 of the distance change observation device 1 in the fourth embodiment described above.

  As shown in FIG. 11, when there is reflected light La and Lb from the objects A and B other than the target TG as described above, as shown in FIG. 12, from a place other than the target TG within a preset time range w. The light reception signal b of the reflected light Lb may be mixed. This is because the distance from the distance change observation device 1 to the target TG and the distance from the distance change observation device 1 to the object B are close to each other.

  As described above, when a plurality of reflected lights are received within the preset time range w, the light receiving unit 4 selects the reflected light with the maximum received light amount G as the true reflected light among them. It is assumed that a light reception signal corresponding to the reflected light is output. Thereby, in the case of FIG. 12, the light reception signal p can be correctly selected instead of the light reception signal b (the case where two reflected lights are received within the time range w is illustrated).

  In order to select the received light signal p more reliably, a reflective surface of the target TG (such as a white plate, a retroreflective element, or a recurring reflective sheet) having a high reflectance is used. As a result, the reflected light L2 that hits the target TG can increase the amount of light compared to the reflected light from an object other than the target TG, the light reception signal p can be selected more reliably, and the structure around the target TG. It is possible to prevent erroneous measurement of erroneously recognizing reflected light caused by a light beam irradiated on an object, and to realize highly reliable observation.

(Sixth embodiment)
FIG. 13 shows a usage state of the distance change observation apparatus according to the sixth embodiment, and FIG. 14 shows a time chart of reflected light reception. In the present embodiment, a process of removing noise caused by an object behind the target TG and increasing the SN ratio is added to the process performed by the light receiving unit 4 of the distance change observation device 1 in the fourth embodiment described above. is there.

  As shown in FIG. 13, the distance from the distance change observation device 1 to the target TG and the distance from the distance change observation device 1 to other objects A, B, etc. are close to each other, and the objects A, B, etc. If it exists behind the target TG, the light reception signal p by the target TG can be correctly selected based on these conditions.

  That is, when the light receiving unit 4 receives a plurality of reflected lights within a preset time range w, the light receiving unit 4 outputs a light receiving signal based on the reflected light first received among them as a light receiving signal by the target TG. Thereby, as shown in FIG. 14, not the light reception signals a and b but the light reception signal p can be correctly selected (the case where three reflected lights are received within the time range w is illustrated).

  The above situation occurs, for example, when a forest or a wall exists behind the target TG. In such a case, a large amount of reflected light La, Lb, etc. is generated when the irradiation light L1 hits the back reflecting object. Further, not only the reflected light from the object behind the target TG but also the reflected light from the target TG and other objects does not directly reach the light receiving unit, but is reflected on the light receiving unit 4 by hitting another reflecting object on the way. Light (secondary reflected light, and hence delayed light) can be effectively removed.

(Seventh embodiment)
FIG. 15 shows the usage state of the distance change observation apparatus according to the seventh embodiment and the polarization state of the reflected light. In this embodiment, a process of increasing the SN ratio by excluding reflected light from objects other than the target TG is added to the process performed by the light receiving unit 4 of the distance change observation device 1 in the first embodiment described above. It is. That is, in the distance change observation device 1, the light receiving unit 4 includes a polarizing filter F such as a polarizing plate so as to receive only reflected light in a specific polarization state, so that light in a specific polarization state is received. Only the light reception signal is output.

  In FIG. 15, the polarization state 13 of the reflected light L2 from the target TG matches the polarization state 11 through which the polarizing filter F is transmitted, and the polarization states 12 and 14 of the reflected light La and Lb from the objects A and B are It does not coincide with the polarization state 11. Therefore, only the reflected light L2 from the target TG is received by the light receiving unit 4 of the distance change observation device 1.

  In order to make the above-described configuration effective, the reflected light L2 in a specific polarization state needs to be reflected from the target TG. For this purpose, a polarizing plate is incorporated in the light projecting optical unit 3 so that the irradiation light L1 has a certain polarization direction. In this case, if an element that changes the polarization, such as a retroreflective prism, is used for the reflection surface of the target TG, it is more preferable because the polarization state change information can be used in addition to the polarization state information.

  Since the polarization direction of only the reflected light L2 reflected by the target TG is changed by the above-described element, the light receiving unit 4 incorporates a polarizing plate so as to transmit only the reflected light in the polarization direction, thereby reflecting from other than the target TG. Light can be excluded efficiently and erroneous measurement can be prevented. In addition, it is not restricted to said polarizing plate to give a polarization direction. For example, when a laser diode is used as the light emitting element in the light projecting unit 2, a certain amount of polarization is applied to the light beam L0 itself, so that it may be used as it is.

  Further, the method of changing the polarization direction in the target TG is not limited to the retroreflective prism, and a reflection plate that changes the polarization direction may be used. In addition, when only the polarization state information is used without using the polarization state change information, if the polarization reflector that reflects only the light of a specific polarization state is installed on the target TG, it is polarized as the irradiation light L1. Light can be used, which is convenient.

  Similarly, the polarizing filter F that transmits only light having a specific polarization direction in the light receiving unit 4 is not limited to a light-transmitting polarizing plate, but a mirror that reflects only a specific polarization direction, and the like. A configuration using the optical member may be used. In addition, the polarization direction of the irradiation light L1 is not always constant, but a time-dependent configuration in which the polarization direction is changed with time and the polarization direction incident on the light receiving unit 4 is changed accordingly. Good.

  As described above, according to the distance change observation device 1 of the present embodiment, the reflected light L2 from the target TG is in a specific polarization state, thereby efficiently reflecting the reflected light from an object other than the target TG. It can be reliably excluded, and erroneous measurement of distance can be prevented to achieve highly reliable observation.

(Eighth embodiment)
FIG. 16 shows a block configuration of a distance change observation apparatus according to the eighth embodiment, and FIGS. 17A and 17B show an initial setting method in the distance change observation apparatus. The present embodiment facilitates adjustment of the spread angle of the irradiation light L1 from the light projecting optical unit 3 of the distance change observation device 1 of the first embodiment described above. That is, the light projecting optical unit 3 of the distance change observation device 1 includes external adjustment means 6 for adjusting the light beam divergence angle θ from the outside of the apparatus main body, and the light receiving unit 4 stores information on the amount of received light. External output means 7 that can be displayed outside, informed, and transferred is provided.

  The external adjustment unit 6 includes a support member 62 that supports the lens 63 and a support member 62 that supports the lens 63 so that the lens 63 in the light projecting optical unit 3 can move in the optical axis direction as indicated by an arrow Δx. And a connected knob 61. By providing such a beam divergence angle adjustment mechanism by the external adjustment means 6, the light beam divergence angle θ can be adjusted from the outside of the main body.

  When the distance change observation apparatus 1 is installed, as shown in FIG. 17A, first, the spread angle θ of the irradiation light L1 is first increased by using the above-described mechanism to change the light projection direction of the distance change observation apparatus 1. Adjust roughly towards the target TG. Next, as shown in FIG. 17B, the spread angle θ of the irradiation light L1 is reduced to finely adjust the light projecting direction so as to hit the target TG. Thereby, when installing the distance change observation apparatus 1, the operation | work which makes irradiation light L1 hit target TG becomes easy.

  In the present embodiment, an example in which the lens 63 inside the light projecting optical unit 3 is moved by a physical mechanism is shown. However, the present invention is not limited to this. For example, the lens 63 may be driven by an electric drive unit such as a motor. Good. That is, an optical member comprising a combination of a lens and a mirror driven by such a drive unit and an operation switch for operating the drive unit, and the drive unit is operated from the outside of the apparatus main body by the operation switch, and the optical member The beam divergence angle θ may be adjusted by moving.

  According to the distance change observation device 1 provided with such an external adjustment means 6, when setting the distance change observation device 1, first, the light beam spread angle θ is increased to roughly adjust the light projection direction, Next, the adjustment of the light beam in the target direction can be easily performed by reducing the spread angle θ and performing the thorough adjustment.

  Further, the external output means 7 has a display function so as to display the received light amount G of the reflected light L2 in real time with a numerical value or a graph when adjusting the light projection direction in FIGS. 17 (a) and 17 (b). Make it. Thereby, when the light receiving unit 4 can receive the reflected light L2 when the irradiation light L1 hits the target TG, the display of the received light amount G is changed, so that the adjustment of the light projecting direction becomes easier.

  Note that the display function of the external output means 7 is not limited to a numerical value or graph display, but may be any function as long as the intensity of the received light amount G can be understood in several stages. For example, in addition to symbols and schematic illustrations, display functions such as lighting numbers, blinking intervals, lighting intensities (brightness), and the like by light emitting elements such as light emitting diodes (LEDs) may be provided. Further, as a method of outputting the received light amount information, a method may be used in which a numerical value is read out by voice, not by display, or by a voice volume or pitch, a voice generation interval, or the like.

  In addition to outputting information on the amount of received light to a display unit and a voice notification unit attached to the apparatus main body of the distance change observation apparatus 1, another apparatus (such as a personal computer or a PDA) connected to the apparatus main body by wire or wirelessly. ) May be transferred to a display unit other than the main body of the apparatus or an audio notification unit.

  According to the distance change observation device 1 provided with such an external output unit 7, the irradiation direction of the irradiation light L1 can be adjusted while reliably recognizing the setting state numerically or perceptually based on the received light amount information, and the distance change The initial setting operation of the observation apparatus 1 can be easily performed. The present invention is not limited to the above-described configuration, and various modifications can be made.

The block block diagram of the distance change observation apparatus which concerns on the 1st Embodiment of this invention. The perspective view of the use condition of a distance change observation apparatus same as the above. (A) is the time chart of irradiation light irradiation in a distance change observation apparatus same as the above, (b) is the time chart of light reception of the reflected light from the target of the irradiation light. (A) is the time chart of the light irradiation which shows the other example of irradiation light in a distance change observation apparatus same as the above, (b) is the time chart of light reception reflected from the target of the irradiation light. The conceptual explanatory drawing of the distance measurement in a distance change observation apparatus same as the above. Explanatory drawing of the distance measurement in a distance change observation apparatus same as the above. (A) (b) (c) (d) is explanatory drawing of the light beam divergence angle adjustment from the light projection part in the distance change observation apparatus which concerns on 2nd Embodiment. (A) (b) (c) is a perspective view in the use condition of the distance change observation apparatus which concerns on 3rd Embodiment. The top view of the use condition of the distance change observation apparatus which concerns on 4th Embodiment. The reflected light reception time chart for demonstrating the determination method of the light reception time in a distance change observation apparatus same as the above. The top view of the use condition of the distance change observation apparatus which concerns on 5th Embodiment. The reflected light reception time chart for demonstrating the determination method of the light reception time in a distance change observation apparatus same as the above. The top view of the use condition of the distance change observation apparatus which concerns on 6th Embodiment. The reflected light reception time chart for demonstrating the determination method of the light reception time in a distance change observation apparatus same as the above. The top view explaining the use condition of the distance change observation apparatus which concerns on 7th Embodiment, and the polarization state of reflected light. The block block diagram of the distance change observation apparatus which concerns on 8th Embodiment. (A) (b) is a top view explaining the initial setting method in a distance change observation apparatus same as the above. (A) is a conceptual explanatory drawing of a general distance change observation apparatus, (b) is a conceptual explanatory drawing of a general distance measuring apparatus. (A) (b) is a perspective view of the conventional distance change observation apparatus. (A) is a perspective view of the conventional distance change observation device in use, (b) is a perspective view for explaining the problems of the conventional distance measurement device, and (c) is another problem of the conventional distance measurement device. The top view explaining a point.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Distance change observation apparatus 2 Light projection part 3 Light projection optical part 4 Light receiving part 5 Distance calculation part 6 External adjustment means 7 External output means t1, t3, ... Projection time t2, t4, ... Light reception time w Time range D Distance G Amount of received light L0 Light beam L1 Irradiated light L2 Reflected light P1 Fixed point P2 Moving point TG Target θ Divergence angle

Claims (6)

In a distance change observation device for observing the change in distance by periodically measuring the distance between the fixed point and the moving point based on the round trip time of the light beam,
A light projecting unit that projects a light beam used for the distance measurement;
A light projecting optical unit configured to irradiate the light beam from the light projecting unit with a spread angle adjusted;
A light receiving unit that receives reflected light from a target that reflects the irradiation light from the light projecting optical unit and outputs a light reception signal;
A distance calculation unit that calculates a distance from the light projecting unit to the target as a distance between the two points based on an elapsed time from a light projecting time of the light beam by the light projecting unit to a light receiving time by the light receiving unit; With
The distance change observation apparatus, wherein the light receiving unit outputs a light reception signal for determining the light reception time only when an elapsed time from the light projection time is within a preset time range.   When the light receiving unit receives a plurality of reflected lights within the preset time range, the light receiving unit selects a reflected light having the maximum received light amount as a true reflected light and corresponds to the reflected light. The distance change observation apparatus according to claim 1, wherein a light reception signal is output.   When the light receiving unit receives a plurality of reflected lights within the preset time range, the light receiving unit selects the reflected light received first as the true reflected light and receives the reflected light corresponding to the reflected light. The distance change observation device according to claim 1, wherein:   The distance change observation apparatus according to claim 1, wherein the light receiving unit receives only light in a specific polarization state and outputs a light reception signal.   The distance change observation apparatus according to claim 1, wherein the projection optical unit includes an external adjustment unit for adjusting the light beam divergence angle from the outside of the apparatus main body.   The distance change observation apparatus according to claim 1, wherein the light receiving unit includes an external output unit that displays or reports information on the amount of received light to the outside.

Images