JP5886092B2 - Multi-point laser distance calculation device - Google Patents

Description

  The present invention relates to a multi-point laser distance calculation device that calculates distances to a plurality of targets using laser light.

  Conventionally, the distance to the reflection means has been measured with a laser distance meter (see, for example, Patent Document 1).

JP 2005-156330 A

  When measuring the distance to a plurality of targets with such a conventional laser distance meter, a plurality of laser distance meters are used. As a result, there is a problem that the cost is increased, and the installation and maintenance of the laser distance meter is complicated by the number of laser distance meters.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a multi-point laser distance calculation device that can calculate distances to a plurality of targets with a simple configuration.

In order to achieve the above object, a multi-point laser distance calculation apparatus according to the present invention includes a single light source unit that emits laser light, and split light emitted in N different directions (N is an integer of 2 or more). One or more beam splitters divided into N, N opening / closing means for switching passage / shielding of the N divided emission lights, and only one of the N opening / closing means is divided emission light. And a control unit that controls the other opening / closing means to shield the divided outgoing light, a light receiving unit that receives reflected light of each of the N pieces of the divided outgoing light, and a control unit that controls the light to pass therethrough. A calculation unit that calculates the distance to the target using the divided outgoing light and the reflected light of the divided outgoing light for each of the N targets that respectively reflect the N divided outgoing lights. It is a thing.
With such a configuration, it is possible to calculate distances to a plurality of targets using laser light emitted from a single light source unit. As a result, the cost for calculating the distances to a plurality of targets can be reduced, and installation and maintenance of the apparatus can be facilitated.

In the multipoint laser distance calculation apparatus according to the present invention, N is 2 or more, and at least N-1 emission direction changing means capable of changing the direction of the divided emission light may be further provided.
With such a configuration, the direction of one split outgoing light is adjusted by changing the direction of the multi-point laser distance calculation device itself, and the direction of the other N−1 split outgoing lights is output. It can be adjusted by using the direction changing means.

In the multi-point laser distance calculation device according to the present invention, the calculation unit calculates the distance to one target in one measurement, and when there is a change in the distance, The distance to the other target is also calculated by the emission of the divided emission light. If there is no change in the distance, the distance to the other target is calculated by the non-emission of the division emission light to the other target. You don't have to.
With such a configuration, when there is no change in the distance to one target, the distance to the other target is not measured, and power consumption can be reduced accordingly. On the other hand, for example, when a plurality of targets are present on the same structure, the same mountain surface, etc., it is considered that other targets will move somewhat as one of the targets moves. Therefore, when there is a change in the distance of one target, it is possible to accurately grasp the more accurate situation if necessary by measuring the distance of other targets. sell.

  According to the multipoint laser distance calculation apparatus according to the present invention, the distances to a plurality of targets can be calculated using laser light emitted from a single light source unit.

The figure which shows the structure of the multipoint laser distance calculation apparatus by Embodiment 1 of this invention. The figure for demonstrating the output direction change means in the embodiment The flowchart which shows operation | movement of the multipoint laser distance calculation apparatus by the embodiment The figure which shows an example of utilization of the multipoint laser distance calculation apparatus by the embodiment The figure for demonstrating the change of the direction of the division | segmentation emitted light in the embodiment The figure for demonstrating the change of the direction of the division | segmentation emitted light in the embodiment

  Hereinafter, a multipoint laser distance calculation apparatus according to the present invention will be described using embodiments. In the following embodiments, components and steps denoted by the same reference numerals are the same or equivalent, and repetitive description may be omitted.

(Embodiment 1)
A multipoint laser distance calculation apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. The multipoint laser distance calculation device according to the present embodiment emits three divided emission lights.

  FIG. 1 is a block diagram showing a configuration of a multipoint laser distance calculation apparatus 1 according to the present embodiment. The multi-point laser distance calculation device 1 according to the present embodiment includes a single light source unit 11, beam splitters 12 and 13, a light receiving unit 14, open / close means 21, 22, and 23, a control unit 25, and a calculation unit. 26, an accumulation unit 27, a displacement detection unit 28, a displacement output unit 29, and emission direction changing means 31 and 32.

  The light source unit 11 emits laser light. The light source unit 11 may generate and emit laser light with a laser diode, for example. The wavelength of the laser beam does not matter. The laser light may be, for example, red laser light having a wavelength of about 650 nm, or laser light having other wavelengths. The diameter of the laser light emitted from the light source unit 11 may be about 3 mm, or may be another diameter.

  The beam splitters 12 and 13 divide the laser light from the light source unit 11 into N divided outgoing lights in different directions (N is an integer of 2 or more). In the present embodiment, a case where N = 3, that is, a case where the beam splitters 12 and 13 divide the laser light into three divided emission lights will be described. The beam splitters 12 and 13 may be any as long as they can split the laser light into outgoing light in different directions. For example, the beam splitters 12 and 13 may be partially transmissive mirrors that partially transmit and reflect the remainder, may be prisms that partially transmit and reflect the other, and other optical devices. It may be. Of the partially transmissive mirrors, those in which transmitted light and reflected light have substantially the same intensity are called half mirrors. Further, it is preferable that the transmittance and the reflectance of each of the beam splitters 12 and 13 are set so that the intensity of the N divided outgoing lights after the division is substantially the same. For example, in the case of the multipoint laser distance calculation device 1 of FIG. 1, the beam splitter 12 transmits 2/3 and reflects 1/3, and the beam splitter 13 transmits 1/2. , 1/2 is preferable. By doing so, the intensity of each divided emission light is 1/3 of the laser light emitted from the light source unit 11. The split emission light may be laser light that is not diffused light, or it may not be. For example, when it is not assumed to measure the distance to a far target, but to measure the distance to a near target, the split outgoing light is not a diffused light. It may be light.

  The light receiving unit 14 receives three reflected lights obtained by reflecting the three divided emission lights by the three targets M1 to M3, respectively. In FIG. 1, the divided emission light emitted from the multipoint laser distance calculation device 1 is reflected by three targets M1 to M3 and reflected by the beam splitters 12 and 13 or transmitted through the beam splitters 12 and 13, respectively. In other words, the light is reflected by the half mirror 17 and enters the light receiving unit 14. The light receiving unit 14 may be anything that can detect light, and may be, for example, a photodiode or a phototransistor.

  Here, the targets M1 to M3 may be anything as long as the divided outgoing light is reflected. That is, as long as it does not absorb the divided outgoing light, it may be anything. The targets M1 to M3 may be, for example, reflecting means. The reflecting means may be a retroreflecting plate in which incident light and reflected light are in the same direction regardless of the incident angle, or may be a reflecting plate (for example, a mirror) that is not a retroreflective plate. When the targets M1 to M3 are retroreflective plates, for example, a corner cube mirror or a corner cube prism may be used, or a fine glass bead may be used. Further, the reflecting surfaces of the targets M1 to M3 that are reflecting means may be flat or curved. Moreover, the shape of the target objects M1-M3 is not ask | required. For example, it may be a circle, a rectangle, a triangle, or another shape. Moreover, the magnitude | size of the target objects M1-M3 is not ask | required. For example, it may be about 20 × 20 cm, may be larger than that, or may be smaller than that. In addition, the targets M1 to M3 may be arranged to reflect the divided outgoing light, or the targets M1 to M3 may be preexisting (for example, a part of a structure or the like). It may be used as The targets M1 to M3 may be provided with, for example, a rainproof cover for preventing rain. When the targets M1 to M3 are retroreflective plates, the emitted light and the reflected light pass through substantially the same optical path.

  A part of the laser light emitted from the light source unit 11 is reflected by the half mirror 15 and received by the light emission detection light receiving unit 16. The reception of the laser beam by the light emission detection light receiving unit 16 is used when calculating the distance to the targets M1 to M3 described later.

  The opening / closing means 21 to 23 respectively switch the passage and shielding of the three divided emitted lights. The opening / closing means 21 to 23 may be any one as long as it can pass or block the divided emitted light. The opening / closing means 21 to 23 may be, for example, a liquid crystal shutter that switches the passage / blocking of the divided emission light by making the liquid crystal transparent or opaque, or a mechanical shutter that mechanically switches the opening / closing. Or other types of shutters may be used. In the present embodiment, the case where the opening / closing means 21 to 23 are liquid crystal shutters will be mainly described.

  The control unit 25 controls so that only one of the three opening / closing means 21 to 23 allows the split outgoing light to pass therethrough, and the other opening / closing means shields the split outgoing light. By performing this control, only a single divided emission light is emitted from the multipoint laser distance calculation device 1. Then, the distance to the target using the single divided outgoing light can be calculated. In addition, the distance to all the targets M1-M3 is computable by switching the division | segmentation emitted light radiate | emitted from the multipoint laser distance calculation apparatus 1 sequentially by the control part 25. FIG. Specifically, the following may be performed. First, the opening / closing means 21 is opened and the opening / closing means 22 and 23 are closed so that the divided emission light is emitted to the target M1. Next, the opening / closing means 22 is opened and the opening / closing means 21 and 23 are closed so that the divided emission light is emitted to the target M2. Finally, the opening / closing means 23 is opened and the opening / closing means 21 and 22 are closed so that the divided emission light is emitted to the target M3. In this way, the distances from the targets M1 to M3 are sequentially measured. The distance measurement will be described later.

The calculation unit 26 calculates the distance to the target using the divided outgoing light controlled to pass by the control unit 25 and the reflected light of the split outgoing light. The distance is the distance to the target reflected by the divided outgoing light. The calculation unit 26 calculates the distance for each of the three targets M1 to M3 that reflect the three divided outgoing lights. The calculation unit 26 measures a time Δt from when the laser light is emitted from the light source unit 11 until it is received by the light receiving unit 14. Then, using the Δt, the distance L from the light source unit 11 to the target can be calculated as L = (c × Δt) / 2. Here, c is the speed of light in the atmosphere. Further, this distance L is sometimes referred to as a baseline length. Further, when it is desired to measure the distance from another position instead of the baseline length, the correction amount may be added or subtracted as appropriate to the baseline length distance L. In other words, the position that becomes the base point of the distance to be measured has a certain degree of arbitraryness. For example, when the target is a part of the structure or reflecting means arranged on the structure, the base line length is usually about 2 m to about 30 m. In addition, for example, when the target is a reflecting means or the like disposed on a mountain in order to detect a mountain collapse, the baseline length may be 30 m or more. Further, the calculation unit 26 may calculate the time Δt using, for example, the phase of the laser beam, may be calculated by measuring the time from the laser beam emission timing to the light reception timing, or It may be calculated by other methods. When measuring the time from the laser beam emission timing to the light reception timing, the light reception timing in the light emission detection light receiving unit 16 of the laser light reflected by the half mirror 15 may be used. Specifically, when laser light is emitted from the light source unit 11, the laser light is detected by the light emission detection light receiving unit 16, and the reflected light of the divided emission light corresponding to the laser light is detected by the light receiving unit 14. The Therefore, the time Δt can be measured by using the time difference between the two detections. The calculation unit 26 may measure the time Δt using the timing at which the light emission detection light receiving unit 16 receives the emitted light, or the laser light is transmitted from the light source unit 11 to the light emission detection light receiving unit 16 at the timing. You may measure time (DELTA) t using the timing correct | amended according to the time until it arrives. The measurement of the time Δt using the light emission detection light receiving unit 16 is already known and will not be described in detail. When the calculation unit 26 does not use the light reception timing of the light emission detection light receiving unit 16 in calculating the distance to the target, the multipoint laser distance calculation device 1 includes the half mirror 15 and the light emission detection light reception unit 16. And may not be provided. For the distance calculation method by the calculation unit 26, see, for example, the above-mentioned Patent Document 1 and the following document.
References: Hiroshi Naya, Masahiro Mizogami, Soichiro Asari, Tomohiro Masunari, Noriichi Shimizu, Hiroyuki Maeda, “Development of a diffusion laser displacement meter and verification of its practicality”, Journal of the Japan Landslide Society, Vol. 44, no. 6, p339-348, 2008

  In addition, the calculation unit 26 may measure the distance at all times, or periodically (for example, every minute, every five minutes, every ten minutes, every hour, every six hours, The distance may be measured every 12 hours, every 24 hours, etc., or irregularly (for example, timing according to detection of occurrence of some event). When measuring the distance regularly, the calculation unit 26 may determine whether it is time to perform measurement by using a clock unit or a clock unit (not shown), for example. In addition, the emission time of the laser light in one measurement may be, for example, 4 seconds or less, or 1 second or less. Further, the calculation unit 26 may calculate the distance a plurality of times in calculating the distance to a certain target, and average the values for the final distance. By doing so, distance errors can be reduced. The calculation unit 26 also performs control processing for driving the light source unit 11 to emit laser light, and signal processing for performing amplification, waveform shaping, peak hold, and the like on an output signal corresponding to light reception from the light receiving unit 14. Means, a time measuring means for measuring time using a clock or the like may be provided.

  The accumulation unit 27 accumulates the three distances calculated by the calculation unit 26 on a recording medium (not shown). In the accumulation, it is preferable to accumulate so that the distance to the target can be known. The recording medium may be included in the storage unit 27 or may exist outside the storage unit 27. The recording medium can be realized by a predetermined recording medium (for example, a semiconductor memory, a magnetic disk, an optical disk, etc.). The storage in the recording medium may be temporary storage in a RAM or the like, or may be long-term storage.

  The displacement detection unit 28 detects changes in the distances to the three targets M1 to M3 using the three distances accumulated by the accumulation unit 27, that is, the respective distances to the targets M1 to M3. To do. The detection may be, for example, detection that the difference between the distance calculated last time and the distance calculated this time exceeds a predetermined threshold for each target. It may be a detection that the difference between the average of the distance calculated in this time and the distance calculated this time exceeds a predetermined threshold, or the distance calculated as a reference and this time It may be detected that the difference from the calculated distance exceeds a predetermined threshold value. The distance calculated as the reference may be the distance calculated for the first time.

  The displacement output unit 29 performs an output related to the displacement detected by the displacement detection unit 28. The output may be, for example, an output of a displacement amount, an output indicating that a displacement has been detected, an output of a warning in which a displacement has been detected, or an output relating to other displacements. Also good. Further, the displacement output unit 29 may perform the output related to the displacement only when the displacement is detected, or the output related to the displacement, that is, the displacement is not detected even when the displacement is not detected. You may output to the effect. In the latter case, even if no displacement is detected, it can be notified by the output that the multipoint laser distance calculation device 1 is operating. The output may be, for example, display on a display device (for example, a CRT or a liquid crystal display), transmission via a communication line to a predetermined device, printing by a printer, or lighting of a warning light. The sound may be output by a speaker, a warning sound by a siren, may be stored in a recording medium, or may be delivered to another component. The displacement output unit 29 may or may not include a device that performs output (for example, a display device, a printer, or a communication device). Further, the displacement output unit 29 may be realized by hardware, or may be realized by software such as a driver for driving these devices. In the present embodiment, a case will be described in which the displacement output unit 29 transmits information indicating that a displacement has been detected and the amount of displacement.

  The emission direction changing means 31 and 32 can change the direction of the divided emission light. The emission direction changing means 31 can change the direction of the divided emitted light emitted to the target M1, and the emission direction changing means 32 changes the direction of the divided emitted light emitted to the target M2. It can be changed.

  FIG. 2 is a diagram showing a detailed configuration of the emission direction changing means 31. The emission direction changing means 32 is assumed to have the same configuration as the emission direction changing means 31 shown in FIG. The emission direction changing means 31 is provided so as to be rotatable about the axis A1 and the axis A2 with respect to the housing 10 of the multipoint laser distance calculation device 1. The support plate 20 of the emission direction changing unit 31 supports the beam splitter 12 and the opening / closing unit 21. Further, the front side of the support plate 20 in the figure can be adjusted in height by two male screws 41 and 42 that are respectively screwed into two female screws provided in the housing 10. That is, by rotating the male screws 41 and 42, the support plate 20 is inclined in the direction of the double arrow B1 about the axis A1. Further, a concave portion 43 is provided on the front side of the support plate 20 in the figure, and a protruding portion 44 a of an eccentric member 44 rotatably provided on the housing 10 is engaged with the concave portion 43. . The eccentric member 44 is provided so as to be rotatable with respect to the housing 10, and a protruding portion 44 a is provided at an eccentric position different from the rotation axis. Therefore, when the eccentric member 44 is rotated, the position of the projecting portion 44a is changed, and in accordance with the change, the support plate 20 is rotated about the axis A2 in the direction of the double arrow B2. Become. Therefore, by using the male screws 41 and 42 and the eccentric member 44, the direction of the divided outgoing light can be adjusted. Needless to say, the emission direction changing means 31 and 32 are not limited to the configuration shown in FIG. 2 as long as the direction of the divided emission light can be adjusted arbitrarily. For example, each of the emission direction changing means 31 and 32 can rotate the beam splitter with the optical axis direction of the incident laser light as the rotation axis (axis A1 in FIG. 2), and the incident laser light. The beam splitter may be rotated with the normal direction of the plane including the optical axis direction and the optical axis direction of the divided outgoing light to be emitted as the rotation axis (axis A1 in FIG. 2). .

  In addition, each component of the multipoint laser distance calculation apparatus 1 is a dustproof waterproof specification, for example, and may be provided inside the housing 10 that is resistant to temperature changes. The exit locations of the divided outgoing lights are dustproof and waterproof by dustproof glasses D1 to D3, respectively. Such a multi-point laser distance calculation device 1 can be used for long-distance measurement in the field. Moreover, the housing | casing 10 may be made into the vibration proof process, for example.

  Further, since the multipoint laser distance calculation device 1 calculates the distance to the targets M1 to M3 according to landslides, landslides, etc., the battery is usually driven in remote areas where no power is supplied. . Therefore, each configuration is preferably a power-saving device with low power consumption. For example, when the liquid crystal shutter consumes less power than the mechanical shutter, the opening / closing means 21 to 23 are preferably liquid crystal shutters.

Next, the operation of the multipoint laser distance calculation apparatus 1 will be described using the flowchart of FIG.
(Step S101) The control unit 25 determines whether it is time to calculate the distance. If it is time to calculate the distance, the process proceeds to step S102. If not, the process in step S101 is repeated until the time to calculate the distance is reached. Note that, as described above, the control unit 25 may determine, for example, that it is a timing for periodically calculating the distance, or a timing for calculating the distance according to the occurrence of another event or the like. You may judge.

  (Step S102) The control unit 25 sets the counter i to 1.

  (Step S103) The control unit 25 controls each of the opening / closing means 21 to 23 so that only the i-th opening / closing means is opened and the other opening / closing means shields the divided emission light.

  (Step S104) The calculation unit 26 controls the light source unit 11 to emit pulsed laser light. As a result, laser light is emitted from the light source unit 11. Then, the laser light is split into three split outgoing lights by the beam splitters 12 and 13. However, since only the i-th opening / closing means is open, the divided emission light is emitted only from the i-th opening / closing means. Then, the reflected light reflected by the target irradiated with the divided emitted light is received by the light receiving unit 14 via the i-th opening / closing means, the beam splitter, and the half mirror 17.

  (Step S105) The calculation unit 26 measures the time Δt related to the laser beam and calculates the distance L to the target using the time Δt.

  (Step S106) The calculation unit 26 determines whether to repeat the distance calculation. If so, the process returns to step S104. If not, the average of the distances calculated so far is calculated, and the process proceeds to step S107. For example, when the distance is calculated a predetermined number of times (for example, 4 or 5 times), the calculation unit 26 determines that the distance is not repeated, and calculates the distance. When the number of times is less than the determined number, it may be determined that the number of times is repeated.

  (Step S107) The storage unit 27 stores the distance calculated by the calculation unit 26 in a recording medium (not shown). Note that the accumulation target distance is an average of distances repeatedly calculated.

  (Step S108) The control unit 25 determines whether or not the counter i is N. Note that N is the number of divided outgoing lights, and in this embodiment, N = 3 as described above. If the counter i is N, the process proceeds to step S110. If not, that is, if it is still less than N, the process proceeds to step S109.

  (Step S109) The control unit 25 increments the counter i by 1. Then, the process returns to step S103.

  (Step S110) For each distance from the target M1 to M3, the displacement detector 28 determines whether there is a change in the distance using the latest accumulated distance and the distance accumulated so far. . If there is a change in the distance to any target, the process proceeds to step S111. If not, that is, if there is no change in the distance to any target, the process returns to step S101. Note that when the distance is calculated for the first time, there is no distance to be compared, and the presence or absence of a change in the distance cannot be determined. Therefore, the process may return to step S101.

(Step S <b> 111) The displacement output unit 29 performs an output related to the displacement detected by the displacement detection unit 28. Then, the process returns to step S101.
In the flowchart of FIG. 3, the process ends when the power is turned off or the process is terminated. Further, in the flowchart of FIG. 3, when the distance measurement is not repeated, the process may proceed from step S105 to step S107. In addition, when output regarding displacement is performed regardless of whether or not there is a change in the distance, when it is determined Yes in step S108, the process may proceed to step S111.

Next, the operation of the multipoint laser distance calculation apparatus 1 according to the present embodiment will be described using a specific example. In this specific example, as shown in FIG. 4, a case will be described in which the multipoint laser distance calculation device 1 detects displacement amounts relating to a plurality of points on a mountain. By doing in this way, it is possible to detect landslides related to a plurality of points on the mountain. In FIG. 4, it is assumed that the targets M1 to M3 as reflecting means are respectively provided at a plurality of positions on the mountain. Here, a method of installing the multipoint laser distance calculation apparatus 1 will be briefly described. As shown in FIG. 5A, the multi-point laser distance calculation apparatus 1 according to the present embodiment is configured to use the elevation angle directions φ ₁ and φ ₂ (direction B1 in FIG. 2) for the divided emitted lights to the targets M1 and M2. And the azimuth angle directions θ ₁ and θ ₂ (B2 direction in FIG. 2) can be changed by the emission direction changing means 31 and 32, respectively. The multipoint laser distance calculation device 1 is installed so as to reach the target M3. It should be noted that the other targets M1 and M2 are also preferably set so that the directions of the divided outgoing lights are substantially matched. Thereafter, by operating the emission direction changing means 31 and 32, adjustment is made so that the divided emission light reaches the targets M1 and M2, respectively. In this way, each of the targets M1 to M3 is irradiated with the divided outgoing light. Here, each divided emission light is assumed to be included in substantially the same plane when the elevation angle direction or the azimuth angle direction is the reference position, and the azimuth angle is an angle with respect to the reference direction in the plane, The elevation angle is an angle in the vertical direction with respect to the plane. Further, when any of the targets M1 to M3 moves due to a mountain collapse or the like, at least one of the distances between the multipoint laser distance calculation device 1 and the targets M1 to M3 changes according to the movement. Will do. Therefore, the change can be detected by the multi-point laser distance calculation device 1, and an alarm regarding a landslide or a warning can be issued according to the detection. In this specific example, it is assumed that the displacement output unit 29 transmits information regarding displacement to a predetermined server. In this specific example, the distance is measured every hour (every hour), and the distance is calculated four times by one measurement for each target, and they are averaged. .

  Suppose one day is 1 am. Then, the control unit 25 determines that the measurement is started (step S101), and first controls the open / close means 21 to 23 so that only the open / close means 21 is opened and the open / close means 22 and 23 are closed (step S101). S102, S103). Then, the control unit 25 instructs the calculation unit 26 to measure the distance to the first target M1. Then, according to the instruction, the calculation unit 26 controls the light source unit 11 to emit laser light. In this specific example, the light source unit 11 is assumed to be a class 2 laser product of 1 mW or less. The emitted laser light is received by the light emission detection light receiving unit 16 and irradiated to the target M1 through the half mirror 17 and the beam splitter 12. The reflected light from the target M1 is received by the light receiving unit 14 through the same path (step S104). When the reflected light is received, the calculation unit 26 calculates a time Δt1 from the time when the light emission detection light receiving unit 16 receives light to the time when the light receiving unit 14 receives light. Then, the calculation unit 26 substitutes the time Δt1 into the above-described equation, calculates the distance L11 to the target M1, and temporarily stores it on a recording medium (not shown) (step S105). Further, the calculation unit 26 repeats the calculation of the distance three more times, calculates the distances L12, L13, and L14, accumulates them on a recording medium (not shown), and averages the distance AL150 (= the average of the distances L11 to L14). (L11 + L12 + L13 + L14) / 4) is calculated and passed to the storage unit 27 (steps S104 to S106). The storage unit 27 associates the distance AL150 with the date and time at that time and the identifier of the target M1 (here, the identifier is “M1”. The same applies to other targets). And stored in a recording medium (not shown) (step S107).

  Thereafter, the control unit 25 controls the open / close means 21 to 23 so that only the open / close means 22 is opened and the open / close means 21 and 23 are closed (steps S108, S109, and S103). Then, the control unit 25 instructs the calculation unit 26 to measure the distance to the second target M2. Then, according to the instruction, the calculation unit 26 controls the light source unit 11 in the same manner as the above-described processing, and uses the light reception time of the light emission detection light reception unit 16 and the light reception time of the light reception unit 14 to achieve the target. The distance L21 to the object M2 is calculated and accumulated (steps S104 and S105). The calculation unit 26 repeats the calculation of the distance three more times, calculates and accumulates the distances L22 to L24, and calculates an average distance AL250 (= (L21 + L22 + L23 + L24) / 4) that is an average of the distances L21 to L24. Then, it is passed to the storage unit 27 (steps S104 to S106). The accumulating unit 27 accumulates the average distance AL250 in a recording medium (not shown) in association with the date and time at that time and the identifier “M2” of the target M2 (step S107).

  Finally, the control unit 25 controls the open / close means 21 to 23 so that only the open / close means 23 is opened and the open / close means 21 and 22 are closed (steps S108, S109, and S103). Then, the control unit 25 instructs the calculation unit 26 to measure the distance to the third target M3. In accordance with the instruction, the calculation unit 26 calculates the average distance AL350 to the target M3 in the same manner as described above, and the storage unit 27 calculates the average distance AL350, the date and time at that time, and the target M3. Is stored in a recording medium (not shown) in association with the identifier “M3” (steps S104 to S107).

  When the displacement detection unit 28 detects that the new distances AL150, AL250, and AL350 are accumulated, the distances AL101, AL201, AL301 corresponding to the oldest date and time stored in the recording medium (not shown), and the new distances AL150, AL250. , The absolute value of each difference from AL350 is calculated. Assume that the absolute values of the differences are AD150, AD250, and AD350, respectively. Then, the displacement detection unit 28 reads a threshold value T stored in advance on a recording medium (not shown), and determines whether each of AD150, AD250, and AD350 exceeds T. In this case, all are not exceeded. Then, the displacement detection unit 28 determines that there is no displacement, and no output relating to the displacement is performed (step S110).

  Note that the processing when the distance difference AD150, AD250 exceeds the threshold value T among the differences AD150, AD250, AD350 between the new distance and the oldest distance will be briefly described. In this case, the displacement detection unit 28 indicates that the distance to the first and second targets has changed and the distance difference AD150, AD250 that has exceeded the threshold value T, the displacement output unit 29. To pass. Then, the displacement output unit 29 transmits the received information to a predetermined transmission destination (step S111). A server (not shown) that has received the information can appropriately issue an alarm, issue an alarm, or check the site according to the reception. In this way, landslides can be detected, which can be used, for example, to prevent major accidents. In such a case, since the multipoint laser distance calculation device 1 is usually installed in a mountain or the like that cannot be easily accessed, it is difficult to frequently perform maintenance and inspection. By using the multi-point laser distance calculation device 1, it is possible to check landslides frequently.

  As described above, according to the multipoint laser distance calculation apparatus 1 according to the present embodiment, the distances to the plurality of targets M1 to M3 are calculated using the laser light emitted from one light source unit 11. And the change in the calculated distance can be detected. Therefore, the detection of the distance to the plurality of targets M1 to M3 and the change in the distance can be realized at a lower cost than when a light source unit is provided for each of the plurality of targets. In addition, there is an advantage that the installation and maintenance of the apparatus becomes easier than the case where a laser displacement meter and a laser distance meter are installed for each of a plurality of targets. Further, since the emission direction changing means 31 and 32 are provided, the direction of the laser light applied to the target M3 can be adjusted by adjusting the installation state of the multipoint laser distance calculation device 1 itself, and the target M1. , M2 can be adjusted by operating the emission direction changing means 31 and 32, respectively. Further, by appropriately adjusting the angles of the beam splitters 12 and 13, the divided emission light can be emitted at an arbitrary angle of about 360 degrees except for a predetermined angle in the direction of the light source unit 11.

  In the present embodiment, the case where the laser light from the light source unit 11 is divided into three divided emission lights has been described, but this need not be the case. The number of divided outgoing lights may be two, for example, or four or more. That is, the multipoint laser distance calculation device 1 only needs to emit a plurality of divided emission lights. When the number of split outgoing lights is other than three, it is preferable to provide a number of beam splitters and opening / closing means corresponding to the number. For example, when the number of divided emission lights is N, the multipoint laser distance calculation apparatus 1 is assumed to include N open / close means. In this case, the number of beam splitters may be, for example, N-1 or may be other numbers. In this case, the number of emission direction changing means may be N−1 or more, for example. When the number of emission direction changing means is N−1, the direction of one divided emission light is adjusted according to the direction of the multipoint laser distance calculation device 1, and the remaining N−1 division outputs are adjusted. The direction of the emitted light may be adjusted using the N-1 emission direction changing means. Therefore, when the multipoint laser distance calculation device 1 includes an emission direction changing unit, N may be an integer of 2 or more. Note that the single divided emission light adjusted according to the orientation of the multipoint laser distance calculation device 1 may be a division emission light having the same optical axis as the laser light emitted from the light source unit 11. Further, the multipoint laser distance calculation device 1 may include the same number of emission direction changing means as the number of divided emission lights.

Further, in the present embodiment, when the laser light is divided into N divided outgoing lights, the direction of N-1 divided outgoing lights can be changed using N-1 outgoing direction changing means. Although the case has been described, this need not be the case. When the laser beam is divided into N divided emission lights, the direction of the N-2 divided emission lights can be changed to the elevation angle direction and the azimuth angle direction using N-2 emission direction changing means. One outgoing direction changing means can be used to change the direction of another divided outgoing light to the azimuth direction, and one rotating means is used to change the direction by the outgoing direction changing means. The direction of the multipoint laser distance calculation device 1 may be changeable around the optical axis of the divided emission light. Note that it is preferable that the direction of the divided emission light that changes only the azimuth direction can be changed to the elevation direction by the rotating means. When N = 3, it is as shown in FIG. 5B. In FIG. 5B, the direction of the divided emitted light toward the target M2 can be changed to the elevation angle direction (φ ₂ ) and the azimuth angle direction (θ ₂ ) by the emission direction changing means. Further, the direction of the divided outgoing light toward the target M1 can be changed to the azimuth direction (θ ₁ ) by the outgoing direction changing means. Further, the rotation means 51 can change the direction (φ) of the multipoint laser distance calculation device 1 around the optical axis of the divided outgoing light to the target M3. In such a case, a method for installing the multipoint laser distance calculation apparatus 1 will be briefly described. For example, first, the multipoint laser distance calculation device 1 is installed so that the divided emission light to the target M3 appropriately reaches the target M3. It should be noted that the other targets M1 and M2 are also preferably set so that the directions of the divided outgoing lights are substantially matched. Thereafter, the azimuth direction of the divided outgoing light to the target M1 is adjusted by the outgoing direction changing means, and the elevation direction of the divided outgoing light to the target M1 is adjusted by the rotating means. Finally, the direction of the divided outgoing light toward the target M2 is adjusted by the outgoing direction changing means.

  In the present embodiment, the beam splitters 12 and 13 mainly describe the case where the laser beam is divided into two laser beams, but this need not be the case. One beam splitter may split the laser beam into three or more laser beams.

  Further, in the present embodiment, a case has been described in which the distances to all targets are calculated in one measurement (for example, see the flowchart of FIG. 3), but this need not be the case. For example, the calculation unit 26 calculates the distance to one target in one measurement, and when there is a change in the distance, the calculation unit 26 determines the other according to the emission of the divided emission light to the other target. The distance to the target is also calculated, and if there is no change in the distance, the distance to the other target may not be calculated according to the non-outgoing of the divided outgoing light with respect to the other target. . In this way, when there is no change in the distance to one target, the distance to the other target is not measured. Therefore, the emission of the divided emission light with respect to the other target is not performed, and accordingly, power consumption related to the light source unit 11 and the opening / closing means can be reduced. On the other hand, for example, when the target is arranged on the same structure, the same mountain surface, or the like, it is considered that the other target moves somewhat according to the movement of any target. Therefore, when there is a change in the distance of one target, it is possible to accurately grasp the more accurate situation if necessary by measuring the distance of other targets. Can be. Here, for example, the calculation unit 26 may determine whether the distance to one target is changed, or the displacement detection unit 28 may determine. In the determination, for example, when the difference between the calculated distance and the reference distance is larger than the threshold value T1, it may be determined that there is a change in the distance. The reference distance may be, for example, a previously calculated distance for the same target, an average of previously calculated distances, or a distance calculated as a reference (for example, 1 (Distance calculated for the second time). Further, the threshold value T1 may be the same as the threshold value used when the displacement detector 28 detects the displacement, or may be smaller than that. In consideration of the purpose of detecting that the distance to another target is displaced by the displacement of the distance to a certain target, the threshold T1 is used when the displacement detection unit 28 detects the displacement. It is preferred that it be smaller than the threshold value. Further, in the calculation of the distance to one target and the calculation of the distance to the other target, as described above, the calculation unit 26 calculates the distance a plurality of times and averages the results. A good distance may be used. In addition, one target for calculating the distance in one measurement may be the same in each measurement, or may be changed so that one target is different for each measurement. In the latter case, assuming that the number of targets is N, the distance of each target is calculated at least once in N measurements. For example, if N = 3, the distance to the target M1 is calculated in the first measurement, the distance to the target M2 is calculated in the second measurement, and the target is calculated in the third measurement. The distance to M3 may be calculated, and the targets M1 to M3 for measuring the distance may be sequentially changed in the fourth and subsequent measurements. When the calculation unit 26 determines whether there is a change in the distance to one target, for example, the multipoint laser distance calculation device 1 includes a storage unit (not shown) in which a reference distance is stored, A storage unit (not shown) in which the distance calculated by the calculation unit 26 is stored for comparison with the reference distance may be provided.

  Moreover, although the case where the average of the distances repeatedly calculated by the calculation unit 26 has been described in the present embodiment, this need not be the case. The calculation unit 26 may calculate the distance calculated once as the distance to the target instead of calculating the average distance.

  In the present embodiment, the case where the multipoint laser distance calculation device 1 includes the emission direction changing units 31 and 32 has been described, but this need not be the case. That is, it is not necessary to change the direction of the divided outgoing light. When the direction of the divided emitted light cannot be changed, for example, the position of the target may be changed in accordance with the direction of the divided emitted light.

  Further, in the present embodiment, the case where a landslide is detected by the multipoint laser distance calculation device 1 has been illustrated, but it goes without saying that the multipoint laser distance calculation device 1 may be used for other purposes. For example, it may be used to detect landslides at multiple points in mountainous areas, may be used to detect deviations at multiple points in buildings such as bridges, sluices, tunnels, and chimneys, or other multiple You may use for the detection of a point shift.

  Further, in the present embodiment, the case has been described in which the multipoint laser distance calculation device 1 detects the displacement of each distance to a plurality of targets, but this need not be the case. The multipoint laser distance calculation device 1 may calculate each distance to a plurality of targets. In that case, the multipoint laser distance calculation device 1 may not include the accumulation unit 27, the displacement detection unit 28, and the displacement output unit 29. In this case, the multipoint laser distance calculation device 1 may include a distance output unit (not shown) that outputs the measured distance. The distance output unit is the same as the displacement output unit 29 except that the distance is output instead of the output related to the displacement, and the detailed description thereof is omitted. Note that, using the distances to a plurality of targets calculated by the multipoint laser distance calculation device 1, for example, the displacement of the distances to the plurality of targets may be detected in another device or the like. Alternatively, the distance itself may be used for some processing.

  In the above embodiment, each process or each function may be realized by centralized processing by a single device or a single system, or may be distributedly processed by a plurality of devices or a plurality of systems. It may be realized by doing.

  In the above embodiment, the information exchange between the components is performed by one component when, for example, the two components that exchange the information are physically different from each other. It may be performed by outputting information and receiving information by the other component, or when two components that exchange information are physically the same, one component May be performed by moving from the phase of the process corresponding to to the phase of the process corresponding to the other component.

  Further, in the above embodiment, information related to processing executed by each component, for example, information received, acquired, calculated, transmitted, and received by each component, and each component Information such as threshold values, mathematical formulas, addresses, etc. used by the elements in the processing may be held temporarily or for a long time on a recording medium (not shown) even when not explicitly stated in the above description. . Further, the storage of information in the recording medium (not shown) may be performed by each component or a storage unit (not shown). Further, reading of information from the recording medium (not shown) may be performed by each component or a reading unit (not shown).

  In the above embodiment, when information used by each component, for example, information such as a threshold value, an address, and various setting values used by each component may be changed by the user Even if it is not specified in the above description, the user may be able to change the information as appropriate, or it may not be. If the information can be changed by the user, the change is realized by, for example, a not-shown receiving unit that receives a change instruction from the user and a changing unit (not shown) that changes the information in accordance with the change instruction. May be. The change instruction received by the receiving unit (not shown) may be received from an input device, information received via a communication line, or information read from a predetermined recording medium, for example. .

  In the above embodiment, when two or more components included in the multipoint laser distance calculation apparatus 1 have communication devices, input devices, etc., the two or more components have a physically single device. Or you may have separate devices.

  In the above embodiment, each component may be configured by dedicated hardware, or a component that can be realized by software may be realized by executing a program. For example, each component can be realized by a program execution unit such as a CPU reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

  Further, the present invention is not limited to the above-described embodiment, and various modifications are possible, and it goes without saying that these are also included in the scope of the present invention.

  As described above, according to the multi-point laser distance calculation device according to the present invention, an effect that the distance to a plurality of targets can be calculated using a single light source is obtained. For example, the distance to a plurality of targets is calculated. It is useful as a device to do.

DESCRIPTION OF SYMBOLS 1 Multipoint laser distance calculation apparatus 11 Light source part 12, 13 Beam splitter 14 Light receiving part 16 Light emission detection light receiving part 20 Support plate 21, 22, 23 Opening / closing means 25 Control part 26 Calculation part 27 Accumulation part 28 Displacement detection part 29 Displacement output part 29 31, 32 Emitting direction changing means 51 Rotating means

Claims (3)

A single light source that emits laser light;
One or more beam splitters that divide the laser light into N different directions of split outgoing light (N is an integer of 2 or greater);
N opening / closing means for switching between passing and shielding of the N divided outgoing lights,
A control unit for controlling so that only one of the N opening / closing means allows the split outgoing light to pass therethrough and the other opening / closing means shields the split outgoing light;
A single light receiving portion for receiving the reflected light of each of the N divided outgoing lights;
The calculation of the distance to the target using the divided emitted light controlled to pass by the control unit and the reflected light of the divided emitted light is performed to calculate the N pieces of light that reflect the N divided emitted lights, respectively. A calculation unit for each of the targets ,
The calculation unit calculates a distance to one target in one measurement, and when there is a change in the distance, the calculation unit can reach the other target by emitting divided emission light to the other target. A multi-point laser distance calculation device that calculates the distance to the other target and does not calculate the distance to the other target due to the non-emission of the divided emission light with respect to the other target when there is no change in the distance . The multipoint laser distance calculation device according to claim 1, wherein one target for calculating a distance in the one measurement is changed so as to be a different target for each measurement. N is 2 or more,
The multipoint laser distance calculation device according to claim 1 or 2 , further comprising at least N-1 emission direction changing means capable of changing the direction of the divided emission light.

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