Measuring device

Abstract

One example is extending the measurable distance while ensuring safety for the human body. [Solution] The measuring device (10) is a device that measures an object by scanning it with pulsed light. The measuring device (10) comprises a light-emitting element (12), a light-receiving unit (14), a movable mirror (16), and a control unit (18). The light-emitting element (12) emits pulsed light. The light-receiving unit (14) receives the reflected pulsed light. The movable mirror (16) changes the direction of emission of the pulsed light. The control unit (18) controls the light emission intensity of the light-emitting element (12). In the measuring device (10), the reflective surface of the movable mirror (16) is oscillated sinusoidally, causing the direction of emission of the pulsed light to move back and forth in the first direction (101). The control unit (18) emits pulsed light of higher intensity in the end region (112) including the end of the first direction (101) of the scanning range than in the central region (114) including the center of the first direction (101) of the scanning range.

Description

Technical Field

[0001] The present invention relates to a measuring device, a positioning system, a measurement system, and a monitoring system.

Background Art

[0002] In order to improve the accuracy of automatic driving of vehicles and the like, it is important to improve the performance of a measuring device that measures the surrounding situation. As one such measuring device, there is one that scans the surroundings with pulsed light for measurement.

[0003] Patent Document 1 describes increasing the sensitivity of a part of a detection area based on vehicle driving state information and external environment information. As methods for increasing sensitivity, there are methods such as adding the light reception values of at least a part of a light receiving element group over a plurality of detection periods, and shortening the interval at which a light projecting unit projects measurement light and increasing the number of times measurement light is projected within a detection period.

[0004] Patent Document 2 describes measuring with patterns of a plurality of pulses having different irradiation intensities in a LIDAR device in which a pulse irradiation source and a photosensitive detector rotate with respect to a base frame.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] On the other hand, the pulsed light used in the measuring device has a high power density. Therefore, it is necessary to ensure safety for the human body so that no harm is caused to the user or people around by the irradiation of the pulse.

[0007] One example of a problem that this invention aims to solve is to increase the measurable distance while ensuring safety for the human body. [Means for solving the problem]

[0008] The first invention is, A measuring device that scans and measures an object with pulsed light, The light-emitting element that emits pulsed light, A light receiving unit that receives the reflected pulse light and A movable mirror that changes the direction of emission of the pulsed light, The system includes a control unit that controls the light emission intensity of the light-emitting element, As the reflective surface of the movable mirror is oscillated in a sinusoidal manner, the direction of emission of the pulsed light moves back and forth in the first direction. The control unit causes the pulsed light to emit a higher intensity pulse in the end region, which includes the end of the scanning range in the first direction, than in the central region, which includes the center of the scanning range in the first direction. It is a measuring device.

[0009] The second invention is, A measuring device according to the first invention, installed on a mobile body, An acquisition unit that acquires map information, The system includes a positioning unit that identifies the position of the moving object based on the acquired map information and the measurement results of the measuring device. It is a location tracking system.

[0010] The third invention is, The device comprises multiple measuring devices according to the first invention, The scanning range of one measuring device and the scanning range of another measuring device are adjacent in the first direction. It is a measurement system.

[0011] The fourth invention is, The device comprises two or more measuring devices according to the first invention, One of the measurement devices and another one of the measurement devices are a monitoring system provided so as to face each other in a plan view.

Brief Description of Drawings

[0012] [Figure 1] It is a figure which illustrates the structure of the measuring device which concerns on 1st Embodiment. [Figure 2] It is a figure which illustrates the hardware structure of the control part which concerns on 1st Embodiment. [Figure 3] It is a figure which illustrates the emission direction (emission angle) of the pulsed light which concerns on 1st Embodiment. [Figure 4] It is a figure which illustrates the relationship between time and emission angle in one line scan in the 1st direction which concerns on 1st Embodiment. [Figure 5] It is a figure which illustrates the change of the pulse intensity (emission power) which concerns on 1st Embodiment. [Figure 6] It is a figure which illustrates the measurable area of the measuring device which concerns on 1st Embodiment. [Figure 7] It is a figure which shows the 1st modification of the change of the pulse intensity which concerns on 1st Embodiment. [Figure 8] It is a figure which shows the 2nd modification of the change of the pulse intensity which concerns on 1st Embodiment. [Figure 9] It is a figure which shows the 3rd modification of the change of the pulse intensity which concerns on 1st Embodiment. [Figure 10] It is a figure which illustrates the relationship between the light emitting element and the movable mirror which concerns on 2nd Embodiment. [Figure 11] It is a figure which illustrates the measurable area of the measuring device which concerns on 2nd Embodiment. [Figure 12] It is a block diagram which illustrates the functional structure of the measuring device which concerns on 2nd Embodiment. [Figure 13] It is a block diagram which illustrates the structure of the position identification system which concerns on 3rd Embodiment. [Figure 14] It is a figure which illustrates the usage environment of the position identification system which concerns on 3rd Embodiment. [Figure 15]This is a block diagram illustrating the configuration of a measurement system according to the fourth embodiment. [Figure 16] This is a block diagram illustrating the usage environment of the measurement system according to the fourth embodiment. [Figure 17] This figure illustrates the configuration and operating environment of the monitoring system according to the fifth embodiment. [Figure 18] This figure shows an example of a monitoring system. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below with reference to the drawings. In all drawings, similar components are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0014] (First embodiment) Figure 1 illustrates the configuration of a measuring device 10 according to the first embodiment. The measuring device 10 is a device that scans an object with pulsed light to perform measurements. The measuring device 10 comprises a light-emitting element 12, a light-receiving unit 14, a movable mirror 16, and a control unit 18. The light-emitting element 12 emits pulsed light. The light-receiving unit 14 receives the reflected pulsed light. The movable mirror 16 changes the direction of emission of the pulsed light. The control unit 18 controls the light emission intensity of the light-emitting element 12. In the measuring device 10, the reflective surface of the movable mirror 16 is oscillated sinusoidally, causing the direction of emission of the pulsed light to move back and forth in the first direction 101. The control unit 18 emits pulsed light of higher intensity in the end region 112, which includes the end of the first direction 101 of the scanning range, than in the central region 114, which includes the center of the first direction 101 of the scanning range. This will be explained in detail below.

[0015] The measuring device 10 is a device that measures the distance from the measuring device 10 to an object within its scanning range based on, for example, the difference between the timing of pulse light emission and the timing of reflected light (reflected pulse light) reception. The pulse light is, for example, infrared light. The pulse light is also, for example, a laser pulse. The pulse light emitted from the light-emitting element 12 and emitted outside the measuring device 10 is reflected by the object and at least a portion of it returns towards the measuring device 10. The reflected light then enters the measuring device 10. The reflected light that enters the measuring device 10 is received by the light-receiving unit 14 and its intensity is detected. Here, the measuring device 10 measures the time from when the pulse light is emitted from the light-emitting element 12 until the reflected light is detected by the light-receiving unit 14. The control unit 18 then calculates the distance between the measuring device 10 and the object using the measured time and the propagation speed of the pulse light. The measuring device 10 is, for example, a lidar (LIDAR: Laser Imaging Detection and Ranging, Laser Illuminated Detection and Ranging, or LiDAR: Light Detection and Ranging) device or a radar device.

[0016] The light-receiving unit 14 receives pulsed light incident on the measuring device 10. As shown in Figure 2, which will be described later, the light-receiving unit 14 includes a light-receiving element 142 and a detection circuit 141. The light-receiving element 142 is a photodiode such as an avalanche photodiode (APD). The light-receiving element 142 includes an IV converter and an amplifier, and outputs a signal indicating the light detection intensity by the light-receiving element 142.

[0017] The movable mirror 16 is, for example, a MEMS mirror that is uniaxially or biaxially movable. By changing the orientation of the reflective surface of the movable mirror 16, the emission direction of the pulsed light emitted from the measuring device 10 can be changed. The movable mirror 16 oscillates sinusoidally with at least one axis as the oscillation axis. This sinusoidal oscillation may be at the resonant frequency of the movable mirror 16. Due to the sinusoidal oscillation of the movable mirror 16, the emission direction of the pulsed light changes to a first direction 101.

[0018] If the movable mirror 16 is a two-axis movable MEMS mirror, the movable mirror 16 only needs to oscillate sinusoidally with respect to at least one axis. With respect to the other axis, it may oscillate in a triangular wave or sawtooth wave pattern, for example. By driving the movable mirror 16 in two axes, a predetermined range can be raster-scanned with pulsed light. The scanning with pulsed light will be described in detail later.

[0019] In the example shown in this figure, the measuring device 10 further comprises a perforated mirror 15 and a condensing lens 17. The pulsed light output from the light-emitting element 12 passes through the holes in the perforated mirror 15, is reflected by the movable mirror 16, and is then emitted from the measuring device 10. The reflected light incident on the measuring device 10 is reflected by the movable mirror 16 and the perforated mirror 15, and then enters the light-receiving unit 14 via the condensing lens 17. The measuring device 10 may further include a collimating lens, a mirror, etc.

[0020] The control unit 18 controls the light-emitting element 12, the light-receiving unit 14, and the movable mirror 16. The control unit 18 also calculates the distance from the measuring device 10 to an object within the scanning range, as described above.

[0021] Figure 2 illustrates the hardware configuration of the control unit 18 according to this embodiment. In this figure, the control unit 18 is implemented using an integrated circuit 80 and electronic circuits. The integrated circuit 80 is, for example, a System On Chip (SoC). The electronic circuits are, for example, a drive circuit 120 for the light-emitting element 12 and a drive circuit 160 for the movable mirror 16.

[0022] The integrated circuit 80 includes a bus 802, a processor 804, a memory 806, a storage device 808, an input / output interface 810, and a network interface 812. The bus 802 is a data transmission path for the processor 804, memory 806, storage device 808, input / output interface 810, and network interface 812 to send and receive data to and from each other. However, the method of connecting the processor 804 and the other components is not limited to bus connection. The processor 804 is an arithmetic processing unit implemented using a microprocessor or the like. The memory 806 is a memory implemented using RAM (Random Access Memory) or the like. The storage device 808 is a storage device implemented using ROM (Read Only Memory) or flash memory or the like.

[0023] The input / output interface 810 is an interface for connecting the integrated circuit 80 to peripheral devices. In this figure, the input / output interface 810 is connected to the drive circuit 120 for the light-emitting element 12, the detection circuit 141 for the light-receiving element 142, and the drive circuit 160 for the movable mirror 16.

[0024] The network interface 812 is an interface for connecting the integrated circuit 80 to a communication network. This communication network is, for example, a CAN (Controller Area Network) communication network. The method by which the network interface 812 connects to the communication network may be wireless or wired.

[0025] The storage device 808 stores program modules for realizing the functions of the control unit 18. The processor 804 reads these program modules into memory 806 and executes them to realize the functions of the control unit 18.

[0026] The hardware configuration of the integrated circuit 80 is not limited to the configuration shown in this figure. For example, the program module may be stored in the memory 806. In this case, the integrated circuit 80 does not need to have a storage device 808.

[0027] Figure 3 illustrates the emission direction (emission angle) of pulsed light according to this embodiment. This figure shows an example where the movable mirror 16 is biaxially movable and raster scanning is performed with pulsed light. The two pivot axes of the movable mirror 16 are orthogonal. In the example shown in this figure, the horizontal direction corresponds to the first direction 101. In this embodiment, the emission angle of the pulsed light changes at equal intervals in the first direction 101 from one end to the other of the scanning range 110. In addition, in the example shown in this figure, the emission direction of the pulsed light changes in a second direction perpendicular to the first direction 101 while reciprocating in the direction of the first direction 101. In this way, by changing the emission direction of the pulsed light with the movable mirror 16, it is possible to scan the scanning range 110 with pulsed light. Then, by detecting the reflected light from an object present in the scanning range 110, the distance from the measuring device 10 to the object can be measured. Although this figure shows an example where pulsed light is emitted in both the forward and return paths of scanning in the first direction 101, pulsed light may be emitted in only one of the forward or return paths.

[0028] The scanning range 110 includes an end region 112 and a central region 114. The end region 112 includes the end of the scanning range 110 in the first direction 101. The end region 112 is present at both ends of a single scanning range 110. The central region 114 includes the center of the scanning range 110 in the first direction 101. The width of the end region 112 and the central region 114 is, for example, the scanning width per unit time, where the unit time is the unit time based on the eye-safe specification, for example, 5 microseconds. The end region 112 may also be a region that includes the first and second pulses from the end but does not include the third pulse at each end. The angular width of the end region 112 and the central region 114 may be 10% or 20% of the scanning angular width in the first direction 101 of the scanning range 110.

[0029] The edge of the edge region 112 coincides with the edge of the scanning range 110. The pulse intensity may or may not change within the edge region 112. Similarly, the pulse intensity may or may not change within the central region 114.

[0030] Figure 4 illustrates the relationship between time and emission angle in a line scan of the first direction 101 according to this embodiment. When the emitted pulsed light is plotted on a graph with time on the horizontal axis and the emission angle in the first direction 101 on the vertical axis, as shown in this figure, the plot draws a sine wave. When the movable mirror 16 oscillates sinusoidally, the angular velocity of the angle change of the reflective surface is faster near the center of the oscillation than near the edges. Therefore, when pulsed light is emitted at equal angular intervals as shown in Figure 3, Δc < Δe holds. Here, Δc is the time interval of pulsed light at the center of the first direction 101, and Δe is the time interval of pulsed light at the edge of the first direction 101. In other words, the pulse number density in the edge region 112 is smaller than the pulse number density in the central region 114.

[0031] Conditions have been established to ensure the safety of the human body when emitting pulsed light. Specifically, the following conditions 1 to 3 must be met. (Condition 1) The energy of each pulse of light must be less than or equal to a predetermined value. (Second condition) The energy determined by the number of pulses and the pulse train must be less than or equal to a predetermined value. However, pulses of 5 μs or less are considered as a single pulse. (Third condition) The average energy of the pulsed light per 10 seconds is less than or equal to a predetermined value.

[0032] In order to satisfy the second condition, the total energy of pulsed light within 5 μs must be less than or equal to a predetermined value. In the measuring device 10 according to this embodiment, as described above, Δc and Δe are different, and the number of pulses per 5 seconds in the edge region 112 is less than the number of pulses per 5 seconds in the central region 114. For example, the number of pulses per 5 seconds in the edge region 112 is 1 or less, while the number of pulses per 5 seconds in the central region 114 is greater than 1. As a result, there may be a difference in the upper limit of a single pulse energy between the edge region 112 and the central region 114.

[0033] In this embodiment, the pulse emission interval is less than 5 μs in the central region 114, and 5 μs or more in the edge regions 112. Note that if the width of the edge region 112 is the scanning width per 5 μs, then each edge region 112 will contain only the first pulse from the edge. Δc is less than 5 μs, and Δe is 5 μs or more.

[0034] Figure 5 illustrates the change in pulse intensity (emission power) according to this embodiment. Region 201 is a region where the pulse interval is 5 μs or longer. That is, the number of pulses emitted in any 5 μs within region 201 is 1 or less. The end region 112 is included in region 201. Region 202 is a region where the pulse interval is shorter than 5 μs. Specifically, in region 202, the pulse interval is 2.5 μs or more and less than 5 μs, and 2 pulses are emitted in 5 μs. The central region 114 is included in region 202.

[0035] In this embodiment, the pulse intensity in region 202 is set to satisfy the second condition described above. In region 202, two pulses are emitted every 5 microseconds, whereas in region 201, the pulse interval is longer than 5 microseconds. Therefore, the upper limit of the pulse intensity determined by the second condition in region 201 is twice the upper limit of the pulse intensity in region 202. The pulse intensity in the end region 112 can be made greater than the upper limit of the pulse intensity determined by the second condition in the central region 114.

[0036] In the example shown in this figure, the pulse intensity in region 201 is constant, and the pulse intensity in region 202 is constant. However, the pulse intensity in region 201 does not have to be constant, and the pulse intensity in region 202 does not have to be constant. The intensity of each pulse in region 201 is greater than the intensity of each pulse in region 202. The average intensity of the pulsed light in region 201 is greater than the average intensity of the pulsed light in region 202. When multiple pulsed light beams are emitted within the end region 112, the pulsed light intensities within the end region 112 may be constant or may differ from one another. When multiple pulsed light beams are emitted within the central region 114, the pulsed light intensities within the central region 114 may be constant or may differ from one another. The average intensity of the pulsed light in the end region 112 is greater than the average intensity of the pulsed light in the central region 114. However, the pulse intensity pattern is not limited to the example shown in this figure.

[0037] Furthermore, the pulse intensities in each region only need to be smaller than the upper limit determined by the second condition; they do not need to be identical. For example, the intensity of each pulse in the end region 112 is between 1.9 and 2.1 times the intensity of each pulse in the central region 114. Also, for example, the sum of pulse intensities over 5 μs in the end region 112 may be between 90% and 110% of the sum of pulse intensities over 5 μs in the central region 114, or between 95% and 105%.

[0038] The control unit 18 emits pulsed light of higher intensity in the end region 112 than in the central region 114 by controlling the pulse intensity, for example as shown in this figure. The control unit 18 may be able to switch between a mode in which the pulse intensity is changed and a mode in which it is not changed in the scanning line of the first direction 101, or it may always emit pulsed light of higher intensity in the end region 112 than in the central region 114.

[0039] Figure 6 illustrates the measurable area 20 of the measuring device 10 according to this embodiment. This figure shows the view from a direction perpendicular to the plane containing the scanning line in the first direction 101. In this embodiment, since the pulse intensity of the end region 112 is higher than the pulse intensity of the central region 114, the measurable distance by pulsed light in the end region 112 is longer than the measurable distance by pulsed light in the central region 114. Therefore, the measurable distance can be increased at the end of the scanning range 110 in the direction of the first direction 101. In addition, the signal-to-noise ratio can be increased at the end of the scanning range 110, thereby improving measurement accuracy. In this way, by making the pulse intensity of the end region 112 greater than the pulse intensity of the central region 114 while considering the upper limit of each region, the overall measurement performance of the measuring device 10 can be improved compared to setting the intensity of all pulses to a constant value in accordance with the upper limit in the central region 114.

[0040] The control unit 18 may control the light-receiving unit 14 such that the signal amplification factor of the light-receiving unit 14 in the edge region 112 is lower than the signal amplification factor of the light-receiving unit 14 in the central region 114. Alternatively, the control unit 14 may be controlled to lower the signal amplification factor of the light-receiving unit 14 as the pulse intensity increases. Changing the signal amplification factor of the light-receiving unit 14 is possible, for example, by changing the voltage applied to the avalanche photodiode if the light-receiving element 142 is an avalanche photodiode. By lowering the signal amplification factor of the light-receiving unit 14 in the region of high pulse intensity, signal saturation of the light-receiving element 142 can be avoided, and highly accurate measurements can be performed.

[0041] Figure 7 shows a first modified example of the pulse intensity change according to this embodiment. In this modified example, the control unit 18 changes the pulse light intensity in three or more steps in the first direction 101. Region 201 is a region where the pulse interval is 5 μs or longer. Region 202 is a region where the pulse interval is shorter than 5 μs. In this modified example, the pulse intensity is further changed within each region 201. By doing so, the amount of change in pulse intensity between adjacent pulses can be reduced, and consequently the operation of the measuring device 10 can be stabilized. In this modified example as well, the pulse intensity in the edge region 112 is higher than the pulse intensity in the central region 114. Also, the pulse intensity increases step by step towards the edge of the scanning range 110.

[0042] Figure 8 shows a second modified example of the pulse intensity change according to this embodiment. In this modified example, the control unit 18 continuously changes the intensity of the pulsed light in the first direction 101. Region 201 is a region where the pulse interval is 5 μs or more. Region 202 is a region where the pulse interval is shorter than 5 μs. In this modified example, the intensity of the pulsed light is changed linearly within region 201. By doing so, as in the first modified example, the amount of change in pulse intensity between adjacent pulses can be reduced, and consequently the operation of the measuring device 10 can be stabilized. In this modified example as well, the pulse intensity in the edge region 112 is higher than the pulse intensity in the central region 114. Also, the pulse intensity increases with each pulse as you move towards the edge of the scanning range 110.

[0043] Figure 9 shows a third modified example of the pulse intensity change according to this embodiment. In this modified example, the control unit 18 changes the intensity of the pulsed light in three or more steps in the first direction 101. Region 201 is a region where the pulse interval is 5 μs or more. Region 202 is a region where two pulses are emitted in 5 μs. Region 203 is a region where three pulses are emitted in 5 μs. In region 203, the pulse interval is 1.7 μs or more and less than 2.5 μs. In region 201, the upper limit of the pulse intensity determined by the second condition is three times the upper limit of the pulse intensity in region 203. Region 203 includes the central region 114. Region 201 includes the end region 112. For example, the intensity of each pulse in the end region 112 is 2.9 times or more and 3.1 times or less the intensity of each pulse in the central region 114. In the example shown in this figure, the sum of pulse intensities over 5 microseconds in the edge region 112 is between 90% and 110% of the sum of pulse intensities over 5 microseconds in the central region 114.

[0044] In this modified example, the pulse intensity in region 201 is constant, the pulse intensity in region 202 is constant, and the pulse intensity in region 203 is constant. However, the pulse intensity in region 201 does not have to be constant, nor does the pulse intensity in region 202, nor does the pulse intensity in region 203 have to be constant. The intensity of each pulse in region 201 is greater than the intensity of each pulse in region 202, and the intensity of each pulse in region 202 is greater than the intensity of each pulse in region 203. The average intensity of the pulsed light in region 201 is greater than the average intensity of the pulsed light in region 202, and the average intensity of the pulsed light in region 202 is greater than the average intensity of the pulsed light in region 203. However, the pulse intensity pattern is not limited to the example shown in this figure.

[0045] Although several pulse intensity change patterns have been illustrated above, the pulse intensity change patterns according to this embodiment are not limited to these examples. As long as pulse light of higher intensity than that of the central region 114 is emitted in the edge region 112, the intensity of the other pulses can be set in various ways within the range that satisfies the first to third conditions.

[0046] Furthermore, although this embodiment shows an example where the pulse intensity of the end regions 112 at both ends is the same, the pulse intensity of the end regions 112 at both ends may be different from each other. Of the two end regions 112, the pulse intensity in only one end region 112 may be higher than the pulse intensity of the central region 114, or the pulse intensity in both end regions 112 may be higher than the pulse intensity of the central region 114. Also, for example, when performing a raster scan, the pulse intensity patterns in multiple scan lines in the first direction 101 may be different from each other or the same.

[0047] As described above, according to this embodiment, the control unit 18 emits pulsed light of higher intensity in the edge region 112, which includes the edge of the first direction 101 of the scanning range, than in the central region 114, which includes the center of the first direction 101 of the scanning range. Therefore, it is possible to increase the measurable distance and improve the measurement accuracy in the edge region of the scanning range.

[0048] (Second embodiment) Figure 10 illustrates the relationship between the light-emitting element 12 and the movable mirror 16 according to the second embodiment. Figure 11 illustrates the measurable area of ​​the measuring device 10 according to this embodiment. The measuring device 10 according to this embodiment is the same as the measuring device 10 according to the first embodiment, except for the points described below.

[0049] The measuring device 10 according to this embodiment includes two light-emitting elements 12. The scanning range of pulsed light from one light-emitting element 12 (the first light-emitting element 12a) and the scanning range of pulsed light from the other light-emitting element 12 (the second light-emitting element 12b) are adjacent in the first direction 101. This will be explained in detail below.

[0050] In the measuring device 10 according to this embodiment, measurements are performed using pulsed light from the first light-emitting element 12a and pulsed light from the second light-emitting element 12b. The measuring device 10 also reflects the light from the two light-emitting elements 12 using the same movable mirror 16. By doing so, the emission direction of the pulsed light from the first light-emitting element 12a and the emission direction of the pulsed light from the second light-emitting element 12b are changed in synchronization. As a result, the emission direction of the pulsed light from the first light-emitting element 12a and the emission direction of the pulsed light from the second light-emitting element 12b never intersect. Since the emission direction of the pulsed light from the first light-emitting element 12a and the emission direction of the pulsed light from the second light-emitting element 12b can always be offset, it is safer for people in the vicinity.

[0051] In this embodiment as well, the control unit 18 increases the pulse intensity in the edge region 112 compared to the pulse intensity in the central region 114 in both the scanning range using pulsed light from the first light-emitting element 12a and the scanning range using pulsed light from the second light-emitting element 12b. Therefore, the measurable distance can be increased at the edges of each scanning range in the first direction 101. In addition, the signal-to-noise ratio can be increased at the edges of each scanning range, thereby improving measurement accuracy.

[0052] As shown in Figure 11, the measurable area of ​​the measuring device 10 according to this embodiment is the sum of the measurable area 20a of the first light-emitting element 12a and the measurable area 20b of the second light-emitting element 12b. Because the measurable distance at the edges of the scanning range is long in both the measurable area 20a and the measurable area 20b, the measuring device 10 as a whole can extend the measurable distance not only near the edges of the scanning range but also near the center. Furthermore, the measuring device 10 as a whole can improve the measurement accuracy not only near the edges of the scanning range but also near the center. The scanning ranges of the first light-emitting element 12a and the second light-emitting element 12b may or may not overlap at their edges. However, it is preferable that the scanning ranges of the first light-emitting element 12a and the second light-emitting element 12b are continuous in the first direction 101, and that there is no gap between them.

[0053] Figure 12 is a block diagram illustrating the functional configuration of the measuring device 10 according to this embodiment. The measuring device 10 according to this embodiment further comprises a first light receiving unit 14a, a second light receiving unit 14b, and a coupling unit 19. Pulsed light output from the first light-emitting element 12a is reflected by the movable mirror 16 and emitted outside the measuring device 10. The pulsed light reflected by an external object returns to the measuring device 10 and is received by the first light-emitting unit 14a. Similarly, pulsed light output from the second light-emitting element 12b is reflected by the movable mirror 16 and emitted outside the measuring device 10. The pulsed light reflected by an external object returns to the measuring device 10 and is received by the second light-emitting unit 14b.

[0054] In this embodiment, the control unit 18 controls the first light-emitting element 12a, the second light-emitting element 12b, the first light-receiving unit 14a, the second light-receiving unit 14b, and the movable mirror 16. The control unit 18 also receives signals from the first light-receiving unit 14a and the second light-receiving unit 14b and calculates the distance from the measuring device 10 to the object, similar to the first embodiment. Specifically, the control unit 18 calculates the measurement result of the scanning range by the first light-emitting element 12a based on the output timing of the first light-emitting element 12a and the light-receiving timing of the first light-receiving unit 14a. The control unit 18 also calculates the measurement result of the scanning range by the second light-emitting element 12b based on the output timing of the second light-emitting element 12b and the light-receiving timing of the second light-receiving unit 14b. The coupling unit 19 acquires and combines the measurement result of the scanning range by the first light-emitting element 12a and the measurement result of the scanning range by the second light-emitting element 12b from the control unit 18. The coupling unit 19 then outputs the combined result as the measurement result of a single continuous region. The coupling unit 19 can combine the measurement result from the first light-emitting element 12a and the measurement result from the second light-emitting element 12b based on the predetermined positional relationship between the scanning range of the first light-emitting element 12a and the scanning range of the second light-emitting element 12b. If the measurement result from the first light-emitting element 12a and the measurement result from the second light-emitting element 12b are images, the coupling unit 19 generates a single image by combining them.

[0055] The coupling unit 19 is implemented, for example, using the integrated circuit 80 shown in Figure 2. The storage device 808 further stores program modules for realizing the functions of the coupling unit 19. The processor 804 further realizes the functions of the coupling unit 19 by reading these program modules into memory 806 and executing them.

[0056] As described above, this embodiment provides the same operation and effects as the measuring device 10 according to the first embodiment. Furthermore, the scanning range of pulsed light from the first light-emitting element 12a and the scanning range of pulsed light from the second light-emitting element 12b are adjacent in the first direction 101. Therefore, the measurable distance near the center of the overall scanning range of the measuring device 10 can be increased, and the measurement accuracy can be improved.

[0057] (Third embodiment) Figure 13 is a block diagram illustrating the configuration of the location identification system 40 according to the third embodiment. Figure 14 is a diagram illustrating the usage environment of the location identification system 40 according to this embodiment.

[0058] The location identification system 40 according to this embodiment comprises a measuring device 10, an acquisition unit 42, and a location identification unit 44. The measuring device 10 is installed on the moving body 30. The acquisition unit 42 acquires map information. The location identification unit 44 identifies the location of the moving body 30 based on the acquired map information and the measurement results of the measuring device 10. The measuring device 10 is the same as the measuring device 10 according to at least one of the first and second embodiments. A detailed explanation follows below.

[0059] The mobile body 30 is, for example, a vehicle, and the measuring device 10 is mounted in the front center of the mobile body 30. However, the measuring device 10 may also be mounted in the rear center of the mobile body 30. The positioning system 40 is a system for determining the position of the mobile body 30.

[0060] The acquisition unit 42 and the location identification unit 44 are implemented, for example, using the integrated circuit 80 shown in Figure 2. The storage device 808 stores program modules for implementing the functions of the acquisition unit 42 and the location identification unit 44, respectively. The processor 804 reads these program modules into the memory 806 and executes them to further implement the functions of the acquisition unit 42 and the location identification unit 44.

[0061] Map information is pre-stored on a server 46, for example, a map information provision service. Map information includes three-dimensional information of structures such as buildings and signs, and their location information (e.g., latitude and longitude). The location identification system 40 communicates with an external server 46, and the acquisition unit 42 acquires map information from the server 46. If the mobile body 30 is equipped with GPS or the like, the acquisition unit 42 only needs to acquire map information in the vicinity of the mobile body 30 based on the location information of the mobile body 30.

[0062] The measuring device 10 detects objects around the mobile body 30 by performing measurements. As shown in Figures 6 and 11, the measuring device 10 has a long measurable distance near the edges of its scanning range, enabling high-precision measurements. As a result, when the mobile body 30 to which the measuring device 10 is attached travels on a road, it is possible to detect structures around the road with high precision.

[0063] The position identification unit 44 generates accurate position information for the moving object 30 by matching the structures shown in the map information acquired by the acquisition unit 42 with the structures detected by the measuring device 10. Specifically, the position identification unit 44 calculates the position of the moving object 30 based on the position information of the matched structures in the map information and the distance between the structures obtained by the measuring device 10 and the measuring device 10. Since the measuring device 10 according to this embodiment is capable of detecting structures around roads with particularly high accuracy, it can also improve the accuracy of the position information of the moving object 30 generated by the position identification unit 44. Consequently, the position information generated by the position identification unit 44 can be used to improve the accuracy of, for example, autonomous driving or navigation.

[0064] As described above, this embodiment provides the same operation and effects as the measuring device 10 according to the first embodiment. Furthermore, in the position identification system 40 according to this embodiment, the position identification unit 44 identifies the position of the moving object 30 based on the acquired map information and the measurement results of the measuring device 10. Therefore, the accuracy of the position information of the moving object 30 can be improved.

[0065] (Fourth embodiment) Figure 15 is a block diagram illustrating the configuration of the measurement system 50 according to the fourth embodiment. Figure 16 is a block diagram illustrating the operating environment of the measurement system 50 according to this embodiment. The measurement system 50 according to this embodiment comprises a plurality of measuring devices 10. The scanning range of one measuring device 10 (first measuring device 10c) and the scanning range of another measuring device 10 (second measuring device 10d) are adjacent in the first direction 101. The measuring devices 10 are the same as the measuring devices 10 according to at least one of the first and second embodiments. A detailed explanation follows below.

[0066] In the measurement system 50 according to this embodiment, measurements are performed by the first measuring device 10c and the second measuring device 10d. In this embodiment as well, the control unit 18 of each measuring device 10 makes the pulse intensity of the edge region 112 higher than the pulse intensity of the central region 114 within the scanning range. Therefore, the measurable distance can be increased at the edges of the first direction 101 of each scanning range. In addition, the signal-to-noise ratio can be increased at the edges of each scanning range, thereby improving measurement accuracy.

[0067] For example, the first measuring device 10c and the second measuring device 10d are mounted side by side near the front center of the moving body 30, which is a vehicle or the like. However, the first measuring device 10c and the second measuring device 10d may also be mounted at the rear center of the moving body 30.

[0068] As shown in Figure 16, the measurable area of ​​the measurement system 50 according to this embodiment is the sum of the measurable area 20c measured by the first measurement device 10c and the measurable area 20d measured by the second measurement device 10d. Because the measurable distance at the edges of the scanning range is long in both the measurable area 20c and the measurable area 20d, the overall measurable distance of the measurement system 50 can be increased not only near the edges of the scanning range but also near the center. Furthermore, the overall measurement accuracy of the measurement system 50 can be improved not only near the edges of the scanning range but also near the center. The scanning ranges of the first measurement device 10c and the second measurement device 10d may or may not overlap at their edges. However, it is preferable that the scanning ranges of the first measurement device 10c and the second measurement device 10d are continuous in the first direction 101 and that there is no gap between them.

[0069] The processing of the measurement system 50 will be described in more detail with reference to Figure 15. The measurement system 50 according to this embodiment further includes a coupling unit 52. The coupling unit 52 acquires and combines measurement results from the first measuring device 10c and the second measuring device 10d. The coupling unit 52 then outputs the combined result as the measurement result of a single continuous region. The coupling unit 52 can combine the measurement result of the first measuring device 10c and the measurement result of the second measuring device 10d based on the predetermined positional relationship between the scanning range of the first measuring device 10c and the scanning range of the second measuring device 10d. If the measurement result of the first measuring device 10c and the measurement result of the second measuring device 10d are images, the coupling unit 52 generates a single image by combining them.

[0070] The coupling unit 19 is implemented, for example, using the integrated circuit 80 shown in Figure 2. The storage device 808 further stores program modules for realizing the functions of the coupling unit 19. The processor 804 further realizes the functions of the coupling unit 19 by reading these program modules into memory 806 and executing them.

[0071] In this embodiment, it is preferable that the pulse light emission ports of the multiple measuring devices 10 are spaced at least 1 cm apart. This prevents simultaneous irradiation of surrounding human bodies with pulse light from the same direction, thus ensuring safety.

[0072] Furthermore, in this embodiment, it is preferable that the emission directions of the multiple measuring devices 10 are synchronized. Synchronization means, for example, that the angle between the emission directions is constant. By doing so, the emission direction of the pulsed light from the first measuring device 10c and the emission direction of the pulsed light from the second measuring device 10d do not intersect. Since the emission direction of the pulsed light from the first measuring device 10c and the emission direction of the pulsed light from the second measuring device 10d can always be offset, it is safer for people in the vicinity.

[0073] As described above, this embodiment provides the same operation and effects as the measuring device 10 according to the first embodiment. In addition, the scanning range of the first measuring device 10c and the scanning range of the second measuring device 10d are adjacent in the first direction 101. Therefore, the measurable distance near the center of the scanning range of the entire measuring system 50 can be increased, and the measurement accuracy can be improved.

[0074] (Fifth embodiment) Figure 17 illustrates the configuration and operating environment of the monitoring system 60 according to the fifth embodiment. The monitoring system 60 according to this embodiment includes two or more measuring devices 10. One measuring device 10 (third measuring device 10e) and another measuring device 10 (fourth measuring device 10f) are arranged to face each other in a plan view. The measuring device 10 according to this embodiment is the same as the measuring device 10 according to at least one of the first and second embodiments. A detailed explanation follows below.

[0075] This figure shows a monitoring system 60 that monitors a rectangular monitoring area 70 using a third measuring device 10e and a fourth measuring device 10f. The monitoring area 70 is, for example, the interior of a room. However, the monitoring area 70 may be a corridor or a specific area indoors, or it may be outdoors. The third measuring device 10e is installed, for example, near the ceiling at one corner of the monitoring area 70. The fourth measuring device 10f is installed near the ceiling at the corner diagonally opposite the corner where the third measuring device 10e is installed. However, the height at which the third measuring device 10e and the fourth measuring device 10f are installed is not particularly limited.

[0076] As described above, the third measuring device 10e and the fourth measuring device 10f are positioned to face each other in a plan view. This facing configuration means, for example, that the angle at which the centerlines of the scanning ranges (field of view) of each measuring device 10 intersect is 45° or less.

[0077] Figure 18 shows a comparative example of a monitoring system. In this comparative example, the area to be monitored 70 is monitored by two measuring devices 90. The measurable area 92 of each measuring device 90 is also shown in this figure. In this comparative example, the intensity of the pulsed light of the measuring device 90 is constant, and the measurable distance is constant. As a result, in the area enclosed by the dashed line in this figure, that is, near the corner of the area to be monitored 70 where no measuring device 90 is provided, there is an area where measurement is impossible with either measuring device 90.

[0078] On the other hand, according to the monitoring system 60 of this embodiment shown in Figure 17, since the measurable distance is long near the edges of the scanning range of each measuring device 10, it is possible to monitor even the corners of the monitored area 70 where no measuring device 10 is provided. In this figure, the measurable area 20e by the third measuring device 10e and the measurable area 20f by the fourth measuring device 10f cover the corners of the monitored area 70. In this way, it is possible to monitor areas that tend to be blind spots, such as corners and edges of the monitored area 70.

[0079] The monitoring system 60 further includes a monitoring terminal 62. The monitoring terminal 62 is, for example, a general-purpose computer or a mobile terminal. The measurement results from the third measuring device 10e and the fourth measuring device 10f are displayed on the screen of the same monitoring terminal 62. In this way, the monitor can simultaneously check the measurement results from the third measuring device 10e and the fourth measuring device 10f, and efficiently monitor the area to be monitored 70.

[0080] As described above, this embodiment provides the same operation and effects as the measuring device 10 according to the first embodiment. In addition, the third measuring device 10e and the fourth measuring device 10f are arranged to face each other in a plan view. This makes it possible to monitor areas that tend to be blind spots, such as corners and edges of the monitored area 70.

[0081] The embodiments described above with reference to the drawings are examples of the present invention, and various other configurations can also be adopted. Examples of reference formats are provided below. 1. A measuring device that scans and measures an object with pulsed light, The light-emitting element that emits pulsed light, A light receiving unit that receives the reflected pulse light and A movable mirror that changes the direction of emission of the pulsed light, The system includes a control unit that controls the light emission intensity of the light-emitting element, As the reflective surface of the movable mirror is oscillated in a sinusoidal manner, the direction of emission of the pulsed light moves back and forth in the first direction. The control unit causes the pulsed light to emit a higher intensity pulse in the end region, which includes the end of the scanning range in the first direction, than in the central region, which includes the center of the scanning range in the first direction. Measuring device. 2. In the measuring device described in 1., The emission angle of the pulsed light changes at equal intervals. Measuring device. 3. In the measuring device described in 1. or 2., In the central region, the pulse emission interval is less than 5 μseconds, and in the edge region, the pulse emission interval is 5 μseconds or longer. Measuring device. 4. In any of the measuring devices described in 1. to 3., The sum of pulse intensities over 5 microseconds in the aforementioned end region is between 90% and 110% of the sum of pulse intensities over 5 microseconds in the aforementioned central region. Measuring device. 5. In any of the measuring devices described in 1. to 4., The control unit changes the intensity of the pulsed light in the first direction in three or more steps. Measuring device. 6. In any of the measuring devices described in 1. to 5., The control unit continuously changes the intensity of the pulsed light in the first direction. Measuring device. 7. In any of the measuring devices described in 1. to 6., The control unit controls the light receiving unit so that the signal amplification factor of the light receiving unit in the end region is lower than the signal amplification factor of the light receiving unit in the central region. Measuring device. 8. In any of the measuring devices described in 1. to 7., The device comprises two of the aforementioned light-emitting elements, The scanning range by the pulsed light from one of the light-emitting elements and the scanning range by the pulsed light from the other light-emitting element are adjacent in the first direction. Measuring device. 9. A measuring device described in any one of 1. to 8. provided on the mobile body, An acquisition unit that acquires map information, The system includes a positioning unit that identifies the position of the moving object based on the acquired map information and the measurement results of the measuring device. Location tracking system. 10. Equipped with multiple measuring devices described in any one of items 1 to 8, The scanning range of one measuring device and the scanning range of another measuring device are adjacent in the first direction. Measurement system. 11. In the measurement system described in 10., The pulse light output ports of the aforementioned multiple measuring devices are separated by 1 cm or more. Measurement system. 12. In the measurement system described in 10. or 11., The emission directions of the multiple measuring devices are synchronized. Measurement system. 13. Equipped with two or more measuring devices described in any one of items 1 to 8, A monitoring system in which one of the measuring devices and the other measuring device are arranged to face each other in a plan view.

[0082] This application claims priority based on Japanese Patent Application No. 2021-038082, filed on 10 March 2021, and incorporates all of its disclosures herein. [Explanation of Symbols]

[0083] 10 Measuring device 12 Light-emitting elements 14 Light receiving part Mirror with 15 holes 16. Movable Mirror 17. Focusing lens 18 Control Unit 19 Joint 20 Measurable area 30 Mobile Units 40 Location tracking systems 42 Acquisition Department 44 Location identification part 46 servers 50 Measurement Systems 52 Joint 60 monitoring systems 62 Surveillance terminals 70 Monitoring Area 80 Integrated Circuits 101 First Direction 110 Scanning range 112 End area 114 Central area

Claims

[Claim 1] A measuring device that scans and measures an object with pulsed light, The light-emitting element that emits pulsed light, A light receiving unit that receives the reflected pulse light and A movable mirror that changes the direction of emission of the pulsed light, The system includes a control unit that controls the light emission intensity of the light-emitting element, As the reflective surface of the movable mirror is oscillated in a sinusoidal manner, the emission direction of the pulsed light moves back and forth in the first direction. The control unit causes the pulsed light to emit a higher intensity pulse in the end region, which includes the end of the scanning range in the first direction, than in the central region, which includes the center of the scanning range in the first direction. Measuring device.

Images