Measurement equipment and programs

Abstract

This measurement device comprises: a light source that emits laser light for irradiating a moving body and that is capable of changing the frequency of the laser light; an interference optical system that separates the laser light into reference light and output light, and that causes interference between the reference light and at least one reflected light beam produced when at least one light beam obtained from the output light is reflected by the moving body, to generate interference light; a light detector that detects the interference light; and a processing circuit that processes a signal outputted from the light detector. The processing circuit generates and outputs a plurality of attribute data relating to the moving body on the basis of measurement data pertaining to the movement body, the measurement data being obtained by processing the signal.

Description

[Technical Field]

[0001] The present disclosure relates to a measurement device and a program. [Background technology]

[0002] ETC (Electronic Toll Collection) is a system that allows drivers to pay tolls on toll roads such as expressways without having to stop their vehicles at toll booths. Tolls are determined by the vehicle classification and the toll system of the road. Vehicle classification is based on vehicle attributes, such as size and number of axles. Toll systems for roads are classified into flat-rate systems, where the toll is determined by the distance traveled, and distance-based systems, where the toll is determined by the distance traveled. When a vehicle passes through an ETC lane, communication takes place between the onboard unit installed in the vehicle and the roadside antenna installed in the lane, and data necessary for calculating the toll, such as information from the entrance toll booth and the vehicle classification, is exchanged. This is how the toll is calculated.

[0003] In ETC, vehicle detectors individually identify vehicles, and based on the results of this recognition, processes such as starting and ending intercommunication, switching roadside displays, and opening and closing gates are performed. Most vehicle detectors are optical, with multiple detectors arranged to determine various conditions, such as the vehicle's length and direction of travel. Furthermore, ETC also determines whether a vehicle with a towing mechanism is being towed and counts the number of axles on large vehicles with lift axle functions for toll calculation purposes. Currently, footplate-shaped sensors grounded to the ground are used as axle sensors to count the number of axles. It has been proposed to replace these sensors with optical sensors.

[0004] Patent Document 1 discloses a vehicle type discrimination device that detects specific parts of a vehicle using so-called TOF (Time Of Flight) technology. Patent Document 2 discloses a system that detects axles of a vehicle based on three-dimensional data of the vehicle acquired by a three-dimensional imaging device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-203291 [Patent Document 2] Patent No. 5478419 [Non-patent literature]

[0006] [Non-Patent Document 1] Christopher V. Poulton, et al., “Frequency-modulated Continuous-wave LIDAR Module in Silicon Photonics”, OFC2016, W4E.3, (2016). Summary of the Invention [Problem to be solved by the invention]

[0007] The present disclosure provides a measurement device that generates a plurality of attribute data items that respectively indicate a plurality of attribute information items related to a moving object. [Means for solving the problem]

[0008] A measurement device according to one aspect of the present disclosure includes a light source that emits laser light for irradiating a moving body and is capable of changing the frequency of the laser light; an interference optical system that separates the laser light into reference light and output light, and generates interference light by causing at least one reflected light beam generated when at least one light beam obtained from the output light is reflected by the moving body to interfere with the reference light; a photodetector that detects the interference light; and a processing circuit that processes a signal output from the photodetector, wherein the processing circuit generates and outputs multiple attribute data regarding the moving body based on measurement data of the moving body obtained by processing the signal.

[0009] A general or specific aspect of the present disclosure may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable recording disk, or as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. A computer-readable recording medium may include a non-volatile recording medium such as a CD-ROM (Compact Disc-Read Only Memory). An apparatus may consist of one or more devices. When an apparatus consists of two or more devices, the two or more devices may be located in a single device or may be located separately in two or more separate devices. In this specification and claims, the term "apparatus" may refer not only to a single device but also to a system consisting of multiple devices. A "system" may include devices installed in remote locations away from other devices and connected via a communication network. [Effects of the Invention]

[0010] According to the technology of the present disclosure, it is possible to realize a measurement device that generates multiple attribute data related to a moving object. [Brief explanation of the drawings]

[0011] [Figure 1A] FIG. 1A is a block diagram schematically illustrating the configuration of a measurement device according to an exemplary embodiment of the present disclosure. [Figure 1B] FIG. 1B is a block diagram that schematically shows the configuration of a measurement device according to a modified example of this embodiment. [Figure 2A] FIG. 2A is a diagram schematically showing the time variation of the frequencies of the reference light and the reflected light beam when the moving object is stationary. [Figure 2B] FIG. 2B is a diagram schematically showing the time change in the frequency of the reference light and the reflected light beam when a moving object approaches the measurement device. [Figure 3A] FIG. 3A is a side view that schematically illustrates an example in which a moving object is scanned by one of a plurality of light beams 20L2b. [Figure 3B] FIG. 3B is a top view that schematically illustrates an example in which a moving object is irradiated with a plurality of light beams from the sides. [Figure 3C] FIG. 3C is a front view that schematically illustrates an example in which a moving object is irradiated with a plurality of light beams from the sides. [Figure 4A] FIG. 4A is a diagram schematically illustrating a first example of the changes over time in the measured speed and the measured distance in three channels at different heights. [Figure 4B] FIG. 4B is a diagram schematically illustrating a second example of the changes over time in the measured speed and the measured distance in three channels at different heights. [Figure 5] FIG. 5 is an enlarged view of a rotating wheel of the moving body. [Figure 6A] FIG. 6A is a front view schematically showing another example in which a moving object is irradiated with a plurality of light beams from the sides. [Figure 6B] FIG. 6B is a diagram showing a schematic diagram of the relationship between the measurement speed and time when the light beam scans the wheel at a height of y=0. [Figure 7] FIG. 7 is a graph showing the time variation of the measured distance and measured speed of a moving object in the example. [Figure 8A] FIG. 8A is a diagram schematically illustrating an example in which vehicle detection and axle detection are output as pulse signals. [Figure 8B] FIG. 8B is a diagram schematically illustrating an example in which the pulse signals of the vehicle detection and the axle detection of FIG. 8A are superimposed and output. [Figure 8C] FIG. 8C is a diagram schematically illustrating an example in which detection of an entry of a moving object and detection of reverse running of a moving object are output as pulse signals. [Figure 9A] FIG. 9A is a front view schematically showing an example in which a moving object is irradiated with a plurality of light beams from above. [Figure 9B] FIG. 9B is a side view that schematically illustrates an example in which a moving object is irradiated with a plurality of light beams from above. [Figure 10A] FIG. 10A is a front view schematically showing yet another example in which a moving object is irradiated with a plurality of light beams from the sides. [Figure 10B] FIG. 10B is a front view schematically showing another example in which a moving object is irradiated with a plurality of light beams from above. [Figure 11] FIG. 11 is a flowchart showing an example of a measurement operation executed by the processing circuit. [Figure 12] FIG. 12 is a flowchart showing another example of the measurement operation executed by the processing circuit. [Figure 13A] FIG. 13A is a diagram schematically illustrating a first example of the installation of a measuring device in an ETC. [Figure 13B] FIG. 13B is a diagram schematically illustrating a second example of the installation of a measuring device in an ETC. [Figure 14] FIG. 14 is a diagram showing a schematic diagram of the positional relationship between the belt conveyor, the plurality of cardboard boxes carried by the belt conveyor, and the measuring device. DETAILED DESCRIPTION OF THE INVENTION

[0012] In this disclosure, all or part of a circuit, unit, device, component, or part, or all or part of a functional block in a block diagram, may be implemented by one or more electronic circuits, including, for example, a semiconductor device, a semiconductor integrated circuit (IC), or an LSI (large scale integration). An LSI or IC may be integrated on a single chip or may be configured by combining multiple chips. For example, functional blocks other than memory elements may be integrated on a single chip. While the terms LSI and IC are used here, the term may be changed depending on the degree of integration, and may be referred to as a system LSI, a VLSI (very large scale integration), or an ULSI (ultra large scale integration). A field programmable gate array (FPGA), which is programmable after LSI fabrication, or a reconfigurable logic device, which can reconfigure connections within an LSI or set up circuit partitions within an LSI, may also be used for the same purpose.

[0013] Furthermore, all or part of the functions or operations of a circuit, unit, device, component, or section can be implemented by software processing. In this case, the software is recorded on one or more non-transitory recording media such as ROMs, optical disks, hard disk drives, etc., and when the software is executed by a processor, the functions specified in the software are performed by the processor and peripheral devices. A system or device may include one or more non-transitory recording media on which software is recorded, a processor, and necessary hardware devices, such as interfaces.

[0014] In this disclosure, "light" refers to electromagnetic waves including not only visible light (wavelength of about 400 nm to about 700 nm), but also ultraviolet light (wavelength of about 10 nm to about 400 nm) and infrared light (wavelength of about 700 nm to about 1 mm). In this specification, ultraviolet light may be referred to as "ultraviolet light," and infrared light may be referred to as "infrared light."

[0015] Exemplary embodiments of the present disclosure will be described below. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not recited in the independent claims that represent the highest concepts will be described as optional components. Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Furthermore, in each figure, substantially identical components are assigned the same reference numerals, and duplicated descriptions may be omitted or simplified.

[0016] First, the findings that form the basis of this disclosure will be described.

[0017] The information acquired by a single conventional optical vehicle detector is whether a vehicle has passed at a certain height and the time it has taken to pass at that height. For this reason, multiple vehicle detectors are appropriately positioned according to the application, in order to measure the length and number of axles of a vehicle, or to detect gaps between vehicles. Furthermore, in an oncoming vehicle detector, a housing that emits light and a housing that receives the light are installed on both sides of the lane, and vehicles passing between the two housings are detected. In addition to increasing the number of housings, the oncoming vehicle detector requires road surface construction to electrically connect the two housings.

[0018] The device disclosed in Patent Document 1 uses TOF technology, which allows the device to be installed on only one side of the lane, thereby avoiding the road surface construction work described above. However, in order to measure the length of a vehicle, multiple devices must be installed.

[0019] In the device disclosed in Patent Document 2, three-dimensional data of a vehicle is acquired using multiple detectors, and a histogram of vehicle height is created from the three-dimensional data. The device can detect the axles based on the histogram. However, data acquired by multiple devices is required to measure the length and speed of the vehicle.

[0020] A measurement device according to an embodiment of the present disclosure can generate multiple attribute data for a moving object using so-called FMCW (Frequency-Modulated Continuous-Wave)-LiDAR (Light Detecting And Ranging) technology with a simple device configuration. The measurement device according to an embodiment of the present disclosure and a program used in the measurement device are described below.

[0021] A measurement device according to a first aspect of the present invention includes a light source that emits a laser beam for irradiating a moving object and is capable of changing the frequency of the laser beam, an interference optical system that separates the laser beam into a reference beam and an output beam and generates interference light by causing at least one reflected light beam generated by reflecting at least one light beam obtained from the output beam on the moving object to interfere with the reference beam, a photodetector that detects the interference light, and a processing circuit that processes a signal output from the photodetector. The processing circuit generates and outputs a plurality of attribute data related to the moving object based on measurement data of the moving object obtained by processing the signal.

[0022] This measuring device can generate a plurality of attribute data relating to a moving object.

[0023] The measuring device according to the second item is the measuring device according to the first item, wherein the plurality of attribute data includes at least one piece of information selected from the group consisting of the passage of the moving body, the size of the moving body, the number of axles of the moving body, the moving speed of the moving body, the moving direction of the moving body, and the type of the moving body.

[0024] In this measuring device, when the moving object is a vehicle, the classification of the vehicle traveling in the ETC lane can be determined from the above-mentioned multiple attribute data.

[0025] A measurement device according to a third item is the measurement device according to the first or second item, wherein the plurality of attribute data are output as at least one pulse signal.

[0026] This measurement device can obtain a plurality of attribute data from at least one pulse signal.

[0027] A fourth aspect of the present invention provides a measurement device according to the third aspect, wherein the at least one pulse signal includes a plurality of pulse signals, the measurement device including a plurality of output ports that respectively output the plurality of pulse signals.

[0028] In this measuring device, a plurality of pulse signals can be obtained from the plurality of output ports.

[0029] A measuring device according to a fifth aspect is the measuring device according to the fourth aspect, wherein the plurality of pulse signals are output in synchronization.

[0030] This measurement device can align the time of a plurality of attribute data obtained from a plurality of pulse signals.

[0031] A sixth aspect of the present invention relates to the measurement device of the third aspect, wherein the at least one pulse signal is a single pulse signal, and the plurality of attribute data are output in a state where they are superimposed on the single pulse signal.

[0032] This measuring device can obtain multiple attribute data from a single pulse signal.

[0033] A measurement device according to a seventh item is the measurement device according to any one of the first to sixth items, wherein the emission direction of the at least one light beam is oblique to the traveling direction of the moving body.

[0034] This measuring device can measure the speed of a moving object.

[0035] A measurement device according to an eighth item is the measurement device according to any one of the first to seventh items, wherein the at least one light beam includes a plurality of light beams. The at least one reflected light beam includes a plurality of reflected light beams, the number of which is the same as the number of the plurality of light beams. The measurement device further includes an optical splitter including a plurality of output ports that splits the output light and outputs light from each of the plurality of output ports. Each of the plurality of light beams corresponds to the light output from one of the plurality of output ports included in the optical splitter.

[0036] In this measurement device, multiple light beams can be obtained from the output light.

[0037] A measurement device according to a ninth item is the measurement device according to the eighth item, wherein the moving body may be irradiated from a side with the plurality of light beams.

[0038] A measurement device according to a tenth item is the measurement device according to the ninth item, wherein the plurality of light beams are emitted from different heights relative to a surface on which the moving body is located.

[0039] This measuring device can estimate the length and height of a moving object by detecting the reflected light beam for each channel onto which the light beam is emitted.

[0040] A measurement device according to an eleventh item is the measurement device according to the tenth item, wherein the plurality of light beams are parallel to the surface.

[0041] In this measuring device, the height of the irradiation point on the moving body where the light beam is irradiated relative to the road surface is equal to the height of the channel from which the light beam is emitted relative to the road surface.

[0042] A measurement device according to a twelfth aspect is the measurement device according to the tenth aspect, wherein the moving body includes a wheel, and one or more of the plurality of light beams are emitted toward the wheel.

[0043] This measuring device can measure the rotational speed of the wheel.

[0044] A measurement device according to a thirteenth item is the measurement device according to the twelfth item, wherein, of the plurality of light beams, one or more light beams are non-parallel to the surface, and the remaining light beams are parallel to the surface.

[0045] This measuring device can more accurately measure the rotational speed of the wheels and the traveling speed of the vehicle body of a moving object.

[0046] A measurement device according to a fourteenth item is the measurement device according to the eighth item, wherein the moving body may be irradiated from above with the plurality of light beams.

[0047] The measurement device according to the 15th item is the measurement device according to the 14th item, wherein the multiple light beams are parallel to a plane that is perpendicular to the surface on which the moving body is located and is parallel to the direction of travel of the moving body.

[0048] This measuring device can accurately measure the length of a moving object and its height relative to the road surface.

[0049] A measuring device according to a sixteenth item includes a light source that emits a laser beam for irradiating a moving object on a road surface and is capable of changing the frequency of the laser beam, an interference optical system that separates the laser beam into a reference beam and an output beam and generates interference light by causing the reference beam to interfere with a plurality of reflected light beams generated when a plurality of light beams obtained from the output beam are reflected by the moving object, an optical splitter that includes a plurality of output ports and splits the output beam to emit the plurality of light beams from the plurality of output ports, a photodetector that detects the interference light, and a processing circuit that processes a signal output from the photodetector. The processing circuit generates and outputs data related to at least one of the length of the moving object, its height relative to the road surface, and its speed based on the signal output from the photodetector.

[0050] By emitting multiple light beams, this measuring device can generate more accurate data regarding at least one of the length of the moving object, its height relative to the road surface, and its speed.

[0051] A computer program according to a seventeenth item is a computer program executed by a computer in a system including a measurement device. The measurement device includes: a light source that emits a laser beam for irradiating a moving object and is capable of changing the frequency of the laser beam; an interference optical system that separates the laser beam into a reference beam and an output beam and causes at least one reflected light beam generated by reflecting at least one light beam obtained from the output beam off the moving object to interfere with the reference beam to generate interference light; a photodetector that detects the interference light; and a processing circuit that processes a signal output from the photodetector. The computer program causes the computer to generate and output a plurality of attribute data related to the moving object based on measurement data of the moving object obtained by processing the signal.

[0052] This computer program can generate a plurality of attribute data relating to a moving object.

[0053] (Embodiment) First, referring to FIG. 1A, an exemplary configuration of a measurement device according to an embodiment of the present disclosure will be described. This measurement device can generate multiple attribute data related to a moving object using multiple light beams emitted from a single housing. FIG. 1A is a block diagram schematically illustrating the configuration of a measurement device 100 according to an exemplary embodiment of the present disclosure. FIG. 1A shows the rear portion of a moving object 10 to be measured. In the example shown in FIG. 1A, the moving object 10 is a standard automobile with four wheels. However, it may also be a large truck with four or more wheels or a motorcycle with two wheels. The moving object 10 is positioned on a road surface. The measurement device 100 shown in FIG. 1A includes a light source 20, an interference optical system 30, an optical splitter 40, multiple optical fibers 42, multiple collimating lenses 44, a photodetector 50, a processing circuit 60, a memory 62, and multiple output ports 70. The multiple output ports 70 include a first output port 70a, a second output port 70b, and a third output port 70c. The measurement device 100 further includes a single housing (not shown) that houses these components. The thick arrows in FIG. 1A represent the flow of light. The thin arrows in FIG. 1A represent the transmission and reception of signals. The measurement device 100 may be installed, for example, beside the lane in which the moving object 10 travels. In the example shown in FIG. 1A, the measurement device 100 is placed on the left side as seen by the driver of the moving object 10, but it may also be placed on the right side.

[0054] The light source 20 emits laser light 20L0 whose frequency can be varied. The frequency can be modulated at a constant time period, such as a triangular wave or a sawtooth wave. The time period can vary. The frequency modulation period can be, for example, 0.1 μs to 10 ms. The frequency modulation amplitude can be, for example, 100 MHz to 10 THz. The wavelength of the laser light can be within the near-infrared wavelength range, for example, 800 nm to 2000 nm. Using near-infrared light as the laser light 20L0 enables sensing using light invisible to the human eye. Alternatively, the wavelength of the laser light 20L0 can be within the visible wavelength range, 400 nm to 800 nm, or within the ultraviolet wavelength range.

[0055] The interference optical system 30 includes a first fiber splitter 32, a second fiber splitter 34, and an optical circulator 36. The first fiber splitter 32 splits the laser light 20L0 emitted from the light source 20 into a reference light 20L1 and an output light 20L2. The first fiber splitter 32 inputs the reference light 20L1 to the second fiber splitter 34 and inputs the output light 20L2 to the optical circulator 36.

[0056] The output light 20L2 is divided into a plurality of light beams 20L 2b When branching the output light 20L2 into multiple light beams 20L, the optical circulator 36 may input the output light 20L2 to the optical branching device 40. The output light 20L2 passes through the optical branching device 40 and is divided into multiple light beams 20L 2b The plurality of light beams 20L are sequentially emitted toward the moving object 10. 2b The moving object 10 is irradiated with a plurality of reflected light beams 20L 3b The optical circulator 36 splits the reflected light beams 20L that have returned after passing through the optical splitter 40. 3b are sequentially input to the second fiber splitter 34. The second fiber splitter 34 splits the reflected light beams 20L into 3b The interference light 20L4, which is the result of superposition and interference of each of the light beams and the reference light 20L1, is input to the photodetector 50.

[0057] The optical splitter 40 includes a plurality of output ports, and splits the output light 20L2 to emit light from each of the plurality of output ports. A plurality of optical fibers 42 of different lengths are connected to the plurality of output ports of the optical splitter 40. The thick ring-shaped lines shown in FIG. 1A represent the wound portions of the optical fibers. A plurality of collimating lenses 44 are attached to the plurality of optical fibers 42, respectively. Each collimating lens 44 collimates the light propagating through the corresponding optical fiber 42 and emits it. In this specification, "collimate" means not only making the light strictly parallel, but also reducing the spread of the light beam. In the above-described manner, a plurality of light beams 20L are output from the plurality of collimating lenses 44. 2b are emitted. 2bEach of the plurality of light beams 20L corresponds to light emitted from one of the plurality of exit ports included in the optical splitter 40. 2b may be parallel to the road surface, for example. In this specification, "A is parallel to B" means not only when A is strictly parallel to B, but also when the angle between A and B is 0° or more and 5° or less.

[0058] The optical fibers 42 are provided at different heights relative to the road surface. In the example shown in FIG. 1A, the lengths of the optical fibers decrease as the height relative to the road surface increases. In other examples, the lengths of the optical fibers may increase as the height relative to the road surface increases, or the lengths of the optical fibers may be irregular relative to the height relative to the road surface. The longer the optical fibers 42, the shorter the light beam 20L. 2b The timing at which the plurality of light beams 20L exit from the collimator lens 44 is delayed. 2b are sequentially emitted toward the moving body 10 at different times.

[0059] The measurement device 100 emits a plurality of light beams 20L. 2b 1A, the plurality of light beams 20L include a plurality of channels that respectively emit light beams 20L, and the plurality of channels may be aligned in a line along a direction perpendicular to the road surface, for example. In this specification, "A is perpendicular to B" does not only mean that A is strictly perpendicular to B, but also means that the angle between A and B is 85° or more and 90° or less. In the example shown in FIG. 1A, the plurality of light beams 20L 2b The light beam 20L is emitted in order of the height of the channels relative to the road surface. 2b is parallel to the road surface, the moving object 10 receives the light beam 20L 2b The height of the illuminated area relative to the road surface is 20L 2b is equal to the height of the emitted channel relative to the road surface. 3bThe reflected light beam 20L returns to the optical fibers 42 from which it was emitted, and is sequentially input to the photodetector 50 at different timings together with the reference light 20L1 via the optical branching device 40, the optical circulator 36, and the second fiber splitter 34. Due to the difference in input timing, the reflected light beam 20L 3b You can see which channel it corresponds to.

[0060] The photodetector 50 detects the interference light 20L4. The photodetector 50 includes one or more photodetection elements. The photodetection elements output a signal corresponding to the intensity of the detected light.

[0061] In the measurement device 100, the following two optical paths overlap each other. In one optical path, the output light 20L2 passes through the interference optical system 30 and the optical splitter 40, and multiple light beams 20L 2b The other optical path is the reflected light beam 20L 3b is the optical path from the moving body 10 to the interference optical system 30. By adopting a coaxial optical system in which both optical paths overlap each other, the configuration of the measurement device 100 can be simplified and stable measurement can be achieved. However, the both optical paths may be designed so that they do not overlap each other.

[0062] The processing circuit 60 controls the operation of the light source 20 and the photodetector 50. The processing circuit 60 processes the signal output from the photodetector 50 using FMCW-LiDAR technology. The processing circuit 60 generates and outputs measurement data related to at least one of the distance and speed of the moving object 10 through signal processing in a non-contact manner. Furthermore, the processing circuit 60 generates multiple attribute data indicating multiple pieces of attribute information related to the moving object 10 based on the measurement data of the distance and / or speed of the moving object 10, and outputs the attribute data from at least one of the multiple output ports 70. The attribute data includes at least one piece of information selected from the group consisting of the passage of the moving object 10, the size of the moving object 10, the number of axles of the moving object 10, the moving speed of the moving object 10, the moving direction of the moving object 10, and the type of the moving object 10. A method for generating the multiple attribute data related to the moving object 10 will be described later.

[0063] The computer program executed by the processing circuit 60 is stored in memory 62, such as ROM or RAM (Random Access Memory). Thus, the measurement device 100 includes a processing device including the processing circuit 60 and memory 62. The processing circuit 60 and memory 62 may be integrated on a single circuit board or may be provided on separate circuit boards. The functions of the processing circuit 60 may be distributed across multiple circuits. The processing device may be installed in a remote location away from the other components and control the operations of the light source 20 and the photodetector 50 via a wired or wireless communication network.

[0064] The multiple output ports 70 may be attached to different locations on the housing, for example. Of the multiple output ports 70, the first output port 70a outputs, for example, measurement data of the distance and / or speed of the moving body 10, and the second output port 70b and the third output port 70c output different attribute data 1 and 2, respectively. When the measurement data and attribute data are output as pulse signals, the multiple output ports 70 output multiple pulse signals, respectively. There is no limit to the number of output ports 70, and it may be determined according to the number of data to be output. Multiple light beams 20L are output from one housing. 2b The configuration for emitting laser light 20L0 is not limited to the measurement device 100 shown in FIG. 1A. A modified example of the measurement device 100 according to this embodiment will be described with reference to FIG. 1B. FIG. 1B is a block diagram that schematically shows the configuration of a measurement device 110 according to a modified example of this embodiment. The measurement device 110 shown in FIG. 1B differs from the measurement device 100 shown in FIG. 1A in that the measurement device 110 includes a plurality of light sources 20, a plurality of interference optical systems 30, and a plurality of photodetectors 50. A portion of the laser light 20L0 emitted from a certain light source 20 passes through the corresponding interference optical system 30 and is converted into a light beam 20L. 2b The remaining part of the laser beam 20L0, the reference beam and the reflected beam 20L 3b The interference light 20L4 obtained by superimposing the above is output from the same interference optical system 30 and detected by the corresponding photodetector 50.

[0065] In the measurement device 110, one processing circuit 60 controls the operations of the multiple light sources 20 and the multiple photodetectors 50. Because there is only one processing circuit 60, it is possible to quickly process the multiple signals output from the multiple photodetectors 50, and to quickly output multiple attribute data.

[0066] In this embodiment, one light beam 20L is emitted from one housing, not multiple light beams. 2b In this case, the measurement device 100 does not need to include the optical splitter 40, the plurality of optical fibers 42, and the plurality of collimating lenses 44 shown in FIG. 1. The output light 20L2 may be a single light beam 20L 2b As a result, the light can be emitted from the optical circulator 36 toward the moving body 10 via one collimating lens 44. An optical fiber 42 may be provided between the optical circulator 36 and the collimating lens 44.

[0067] As used herein, "at least one light beam 20L obtained from the output light 20L2" 2b " refers to one light beam corresponding to the output light 20L2. 20 L 2b , or a plurality of light beams 20L obtained by passing the output light 20L2 through the optical splitter 40. 2b means.

[0068] Next, FMCW-LiDAR technology will be briefly explained with reference to Figures 2A and 2B. FMCW-LiDAR technology makes it possible to realize a measurement device that is highly vibration-resistant, has a wide dynamic range for distance, and has high spatial resolution, and is capable of measuring the speed of a moving object. Details of FMCW-LiDAR technology are disclosed in, for example, Non-Patent Document 1.

[0069] FIG. 2A shows the reference light 20L1 and the reflected light beam 20L when the moving object 10 is stationary. 3b2A is a diagram showing a schematic diagram of the change in frequency of the reference light 20L1 over time. The solid line represents the reference light, and the dashed line represents the reflected light beam. The frequency of the reference light 20L1 shown in FIG. 2A repeats a time change of a triangular wave. That is, the frequency of the reference light 20L1 increases linearly during one period, and then decreases linearly by the same amount as the increase. The reflected light beam 20L 3b The frequency of the output light 20L2 is compared with the frequency of the reference light 20L1, and is determined by the frequency of the reflected light beam 20L2 that is emitted from the measurement device 100 and reflected by the moving object 10. 3b As a result, the reference light 20L1 and the reflected light beam 20L 3b The interference light 20L4 is a reflected light beam 20L 3b The interference light 20L4 has a frequency corresponding to the difference between the frequency of the interference light 20L1 and the frequency of the reference light 20L1. The double arrow in FIG. 2A represents the difference between the two frequencies. The photodetector 50 outputs a signal indicating the intensity of the interference light 20L4. This signal is called a beat signal. The frequency of the beat signal, i.e., the beat frequency, is equal to the difference between the above frequencies. The processing circuit 60 can generate data regarding the distance from the measurement device 100 to the moving object 10 from the beat frequency.

[0070] FIG. 2B shows the relationship between the reference light 20L1 and the reflected light beam 20L when the moving object 10 approaches the measurement device 100. 3b 1 is a diagram showing a time variation of the frequency of the reflected light beam 20L due to the Doppler shift when the moving object 10 approaches. 3b The frequency of the reflected light beam 20L is shifted in the positive direction along the frequency axis compared to when the moving body 10 is stationary. 3b The amount of frequency shift of the reflected light beam 20L is calculated by dividing the velocity vector at a certain part of the moving body 10 by the 3b The beat frequency depends on the component projected in the direction of the reference beam 20L1 and the reflected light beam 20L. 3bThe beat frequency differs depending on whether the frequencies of the two signals increase linearly or decrease linearly. In the example shown in FIG. 2B, the beat frequency when the two frequencies decrease linearly is higher than the beat frequency when the two frequencies increase linearly. The processing circuit 60 can generate data related to the velocity of the moving object 10 from the difference in beat frequency. Furthermore, the processing circuit 60 can generate data related to the distance of the moving object 10 from the average value of the two different beat frequencies.

[0071] Next, referring to FIGS. 3A to 3C, the moving object 10 emits a light beam 20L 2b 3A to 3C, for ease of explanation, mutually orthogonal X-, Y-, and Z-axes are shown. However, these axes do not limit the orientation of the moving body 10 and the measuring device 100, and the orientation of the moving body 10 and the measuring device 100 is arbitrary. The +X direction is the direction of the X-axis arrow, and the -X direction is the opposite direction. The same applies to the ±Y and ±Z directions.

[0072] FIG. 3A shows a moving object 10 emitting a plurality of light beams 20L. 2b 3B and 3C are side views each showing an example in which the moving object 10 is scanned by one of the plurality of light beams 20L from the side. 2b 3B is a top view and a front view showing an example in which a plurality of light beams 20L are irradiated. 2b overlap each other to form a single light beam of 20L 2b The multiple reflected light beams 20L are shown as 3b 3B and 3C, the side surface of the moving object 10 emits a plurality of light beams 20L. 2b The side surface of the moving body 10 is a portion of the moving body 10 that can be seen when viewed from the +Z direction side or the −Z direction side, that is, in a side view.

[0073] As shown in Figures 3A to 3C, the +X direction is the direction opposite to the traveling direction of the mobile object 10 and is parallel to the road surface on which the mobile object 10 is traveling. The +Y direction is perpendicular to the road surface and is a direction away from the road surface. The +Z direction is perpendicular to the traveling direction of the mobile object 10 and is a direction parallel to the road surface and is a direction from the mobile object 10 toward the measurement device 100 when the mobile object 10 and the measurement device 100 are facing each other. The XZ plane is parallel to the road surface, the YZ plane is perpendicular to the traveling direction of the mobile object 10, and the XY plane is perpendicular to the road surface and is a direction away from the mobile object 10. of 10 It is parallel to the direction of travel.

[0074] 3A and 3B indicate the traveling direction of the moving object 10. The thick arrow in FIG. 3A indicates that the moving moving object 10 is irradiated with a plurality of light beams 20L. 2b 3B and 3C, the arrows pointing from the measurement device 100 to the moving object 10 represent the positions and directions of the light beams 20L. 2b The arrows pointing from the moving body 10 to the measuring device 100 represent the multiple reflected light beams 20L 3b The angle φ shown in FIG. 3B represents the angle of the plurality of light beams 20L 2b represents the angle formed by each of the light beams 20L and the YZ plane. The angle φ can have a positive value as well as a negative value. When the angle φ is a positive value, the light beams 20L 2b are emitted obliquely from the front toward the moving body 10, and when the angle φ is a negative value, a plurality of light beams 20L 2b are emitted obliquely from behind toward the moving body 10. In the example shown in FIG. 3B, the absolute value of the angle φ may be, for example, greater than 0° and equal to or less than 85°. A more preferable absolute value of the angle φ may be equal to or greater than 5° and equal to or less than 30°. 2b The emission direction of the plurality of light beams 20L is oblique to the traveling direction of the moving object 10. 2b are parallel to the XZ plane. 2b The light beams 20L are located in a plane perpendicular to the XZ plane and intersect with the YZ plane at an angle φ. 2bThe multiple channels from which the respective beams are emitted are aligned in a line along a direction perpendicular to the XZ plane.

[0075] If the absolute value of the traveling speed of the moving body 10 is V (m / h), the traveling speed vector of the moving body 10 is V1 = (-V, 0, 0). On the other hand, the reflected light beam 20L 3b The unit vector parallel to the direction of the moving object 10 is N=(-sinφ, 0, cosφ). The velocity measured by the measurement device 100 is calculated by integrating the velocity vector at a certain part of the moving object 10 with the reflected light beam 20L. 3b In other words, the measured speed is obtained by the dot product of the speed vector at a certain part of the moving body 10 and the unit vector N. The measured speed at the vehicle body of the moving body 10 is obtained by the dot product of the traveling speed vector V1 and the above unit vector N, and is expressed by the following equation (1).

number

[0076] Since the angle φ is known, when the angle φ≠0°, the traveling speed V of the moving object 10 can be calculated by dividing the measured speed v1 by sin φ. 2b When the emission angle of the reflected light beam 20L is φ=0°, the measured speed v1 is zero because the traveling speed vector V1 and the unit vector N are orthogonal to each other. 3b The length of the moving object 10 in each channel can be calculated by multiplying the time at which the light beam 20L is detected by the traveling speed V of the moving object 10. 2b Even if the emission angle of the multiple reflected light beams 20L is φ=0°, 3b Of 、 Which channel's reflected light beam 20L 3b By checking whether or not the height of the moving body 10 relative to the road surface is detected, it is possible to estimate the height of the moving body 10 relative to the road surface.

[0077] Multiple light beams 20L 2bIf none of the light beams 20L hit the moving object 10, the measured speed is zero and the measured distance is longer than a predetermined distance in all channels. 2b is the distance traveled through the lane, and is W / cosφ, where W is the width of the lane. If such measured speeds and measured distances are obtained, the processing circuit 60 determines that the mobile object 10 is not present in the lane.

[0078] Alternatively, the measuring device 100 is installed on one side of the ETC lane in which the moving object 10 travels, and the light beam 20L is installed on the other side. 2b In a configuration in which a beam damper that absorbs the plurality of light beams 20L is installed, it can be determined that the moving object 10 is not present in the lane as follows. 2b If none of the reflected light beams 20L hit the moving object 10, 3b The reflected light beam of 20L is not reflected in all channels. 3b If the unintended reflected light beam 20L is not detected, the processing circuit 60 determines that there is no moving object 10 in the lane. 3b Since no such phenomenon occurs, it is possible to reduce the adverse effects of erroneous detection and diffuse reflection on other detectors.

[0079] The installation of the beam damper does not require wiring, and does not require highly accurate alignment between the beam damper and the measuring device 100. In a case where there are multiple ETC lanes, and the front surface of the measuring device 100 installed beside one ETC lane faces the back surface of the measuring device 100 installed beside the adjacent ETC lane, the back surface may function as a beam damper.

[0080] Next, an example of the change over time in the measurement speed and the measurement distance when multiple beams are emitted will be described with reference to Figures 4A and 4B. Figures 4A and 4B are diagrams that schematically show an example of the change over time in the measurement speed and the measurement distance in three channels at different heights. Figures 4A and 4B show a moving body 10 with wings attached to its rear. The illustration of the moving body 10 shows the change over time in the measurement speed and the measurement distance, and the multiple light beams 20L of the moving body 10. 2b The relationship between the scanning position by the radar and the radar beam is clear. The example shown in Fig. 4B differs from the example shown in Fig. 4A in that, when the mobile object 10 is viewed from the side, an obstacle 12 such as a piece of paper flying through the air overlaps the wing of the mobile object 10. The three channels are numbered ch.1, ch.2, and ch.3 in order of increasing height from the road surface.

[0081] In the example shown in FIG. 4A, ch.1 is located at a higher position than the moving object 10, and the light beam 20L emitted from ch.1 2b does not hit the moving object 10. Therefore, in a configuration in which a beam damper is not provided, the measured speed is zero and the measured distance is longer than the predetermined distance. Ch.2 is located at a height position near the center of the windshield and at the wing of the moving object 10, and Ch.3 is located at a height position near the top of the bumper of the moving object 10. Therefore, in Ch.2 and Ch.3, the moving object 10 does not hit the light beam 20L 2b During the irradiation time, the measurement speed is equal to the measurement speed v1 expressed by Equation (1), and the measurement distance is 2b The measured speed of ch.2 is equal to the distance between the measuring device 100 and the moving object 10 in the direction of the arrow. In ch.2, the measured speed becomes zero midway and the measured distance becomes longer than the predetermined distance due to the gap between the wing of the vehicle body and the rear window located in front of it. In ch.3, the irradiation time is longer than in ch.2. 2b is parallel to the road surface, it is easy to know which of the multiple channels the moving object 10 has passed in front of.

[0082] The maximum length of the moving object 10 obtained from ch.1, ch.2, and ch.3 can be estimated as the length of the moving object 10, i.e., vehicle length. Furthermore, from the results of ch.1 and ch.2, it can be seen that the height of the moving object 10 relative to the road surface, i.e., vehicle height, is equal to or greater than the height relative to the road surface of ch.2 and less than the height relative to the road surface of ch.1. In this case, the average value of these heights can be estimated as vehicle height. By increasing the number of channels and narrowing the spacing between adjacent channels, vehicle length and height can be estimated more accurately.

[0083] In the example shown in Fig. 4B, the obstacle 12 falls from the front to the rear of the moving body as indicated by the dashed arrow. In this case, the speed of the obstacle 12 is such that the reflected light beam 20L 3b The component projected in the direction of is negative. Therefore, in ch.2, the light beam 20L 2b At times when obstacle 12 is illuminated, the measured velocity becomes negative, as indicated by the open arrow in FIG. 4B. Thus, if the non-zero measured velocity at a certain time is significantly different from the non-zero measured velocity at another time, processing circuit 60 determines that some abnormality has occurred. This determination can be made, for example, by determining whether the difference between the non-zero measured velocities at two times exceeds a reference value.

[0084] In the above example, the vehicle body of the moving body 10 is irradiated with the light beam 20L. 2b Next, referring to FIG. 5, a rotating wheel of the moving body 10 is irradiated with the light beam 20L. 2bAn example in which the light is emitted from the wheel 14 is described below. FIG. 5 is an enlarged view of a wheel 14 of a moving object 10 that rotates counterclockwise. Of the wheel 14 shown in FIG. 5, the inner circle 14a represents the wheel, and the outer ring 14b represents the tire. In the example shown in FIG. 5, the maximum radius of the wheel 14 is R (m), the distance of a straight line from the center of the wheel 14 to position P is r (m), and the angle obtained by rotating this line from the X axis is A. The X and Y components of position P in an XY coordinate system with the center of the wheel 14 as the origin are x = r × cosA and y = r × sinA, respectively. The absolute value of the rotational speed of the wheel 14 at position P is Vr / R, and the rotational speed vector is (-sinA × Vr / R, cosA × Vr / R, 0) = (-(y / R)V, (x / R)V, 0). The velocity vector of the rotating wheel is a resultant velocity vector of the traveling velocity vector V1 and the rotational velocity vector of the moving body 10, and is V2 = (-V-(y / R)V, (x / R)V, 0). The measured velocity of the rotating wheel of the moving body 10 is the velocity vector V2 and the reflected light beam 20L. 3b It is obtained by the dot product with the unit vector N=(-sinφ, 0, cosφ) which is parallel to the direction of the axis, and is expressed by the following equation (2).

number

[0085] The measurement speed v2 in equation (2) differs from the measurement speed v1 in equation (1) by V(y / R) sinφ. 2b When scanning the wheel at a height y>0, the measurement speed v2 is higher than the measurement speed v1. 2b When scanning the wheel at a height where y<0, the measured speed v2 is lower than the measured speed v1. In these cases, it is possible to determine which position on the moving body 10 is the body or the rotating wheel from the difference between the measured speed of the rotating wheel and the measured speed of the body. However, unless the component of V(y / R)sinφ is large to a certain extent, the difference between the measured speed of the rotating wheel and the measured speed of the body will not be clear. 2bWhen scanning the wheel at a height of y=0, the measured velocity v2 is equal to the measured velocity v1, and there is no difference between the two.

[0086] 6A and 6B, a method for making the difference between the measured speed at the rotating wheel and the measured speed at the vehicle body clearer will be described. 2b 6A is a front view showing another example in which a plurality of light beams 20L are irradiated. 2b Of these, one or more light beams 20L 2b are emitted towards the rotating wheel, and the one or more light beams 20L 2b is non-parallel to the XZ plane. The remaining light beam 20L 2b The angle θ shown in FIG. 6A is the angle at which one or more light beams 20L are emitted toward the vehicle body and parallel to the XZ plane. 2b represents the angle between the XZ plane and the light beam 20L. The angle θ can have not only a positive value but also a negative value. When the angle θ is a positive value, the output light 20L2 is emitted obliquely from above toward the side of the moving body 10, and when the angle θ is a negative value, the output light 20L2 is emitted obliquely from below toward the side of the moving body 10. When the absolute value of the angle θ is large, the light beam 20L 2b The height at which the output light 20L2 scans the moving object 10 varies greatly depending on the moving object 10's position in the lane. When the absolute value of the angle θ is small, the height at which the output light 20L2 scans the moving object 10 can be easily adjusted. The absolute value of such angle θ can be, for example, 0° or more and 15° or less. 2b The remaining light beam is 20L 2b Similarly, it intersects the YZ plane at an angle φ as shown in FIG. 3B.

[0087] In the example shown in FIG. 6A, the reflected light beam 20L returning from the rotating wheel 3b The unit vectors parallel to the direction of are N=(-sinφ, sinθ, (1-sin 2 φ-sin 2 θ) 1 / 2The measured velocity of a rotating wheel of the moving body 10 is obtained by the dot product of the velocity vector V2 and the unit vector N, and is expressed by the following equation (3).

number

[0088] The measurement speed v3 in equation (3) differs from the measurement speed v1 in equation (1) by V(x / R)sinθ+V(y / R)sinφ. The component of V(x / R)sinθ causes the light beam 20L 2b When scanning the wheel at a certain height, the measured velocity v3 increases with time.

[0089] FIG. 6B shows the light beam 20L 2b 6B is a diagram showing a relationship between the measurement speed and time when the light beam 20L scans the wheel at a height of y=0. FIG. 6B shows a wheel rotating counterclockwise. The part other than the wheel is the vehicle body. As shown in FIG. 6B, the light beam 20L 2b During the time when the vehicle body is scanned, the measurement speed is constant and non-zero regardless of time, and the light beam 20L 2b As the light beam 20L scans the rotating wheel, the measurement speed increases linearly with time. 2b When the light beam 20L scans the wheel at a height y>0, the linear time variation of the measured velocity is shifted upward along the measured velocity axis by V(y / R)sinφ. 2b scans the wheel at a height y<0, the linear time variation of the measured velocity is shifted downward along the measured velocity axis by V(y / R)sinφ.

[0090] As mentioned above, the light beam 20L 2bIf the XZ plane is non-parallel, the difference between the measured speed of the rotating wheels and the measured speed of the vehicle body can be clearly identified. Therefore, the processing circuit 60 can determine which positions on the moving body 10 are the vehicle body and which are the rotating wheels from the measured speed. As a result, the speed data caused by the rotating wheels can be removed and the running speed and length of the moving body 10 can be calculated from the speed data of the vehicle body. Furthermore, the number of rotating axles can be counted from the speed data caused by the rotating wheels. Details of the measured speed of the rotating wheels are disclosed in Japanese Patent Application No. 2021-040245.

[0091] As shown in FIG. 6A, the light beam 20L 2b When the beam is emitted non-parallel to the XZ plane, the height H of the ith channel relative to the road surface is i is the light beam 20L emitted from the i-th channel 2b The height h of the irradiation point of the moving object 10 relative to the road surface is i The distance between the i-th channel and the irradiation point is L i Then, the height of the irradiation point relative to the road surface h i is expressed by the following equation (4).

number

[0092] According to equation (4), the height h of the irradiation position corresponding to the i-th channel relative to the road surface i As described above, when the moving object 10 receives the light beam 20L from the side, 2b When illuminated with a light beam of 20L 2b Even if the XZ plane is not parallel, the height of the irradiation position relative to the road surface can be determined.

[0093] Next, an example in which the distance and speed of a moving object 10 are measured using the measurement device 100 according to this embodiment will be described with reference to Fig. 7. In this example, one light beam 20L 2b The body and rotating wheels of the moving object 10 are irradiated with the light beam 20L.2b The irradiation direction of the light beam 20L was parallel to the road surface and intersected with the traveling direction of the moving body 10. Fig. 7 is a graph showing the time variation of the measured distance and measured speed of the moving body 10 in the example. Fig. 7 shows the measurement device 100, the moving body 10, and the light beam 20L. 2b In the example shown in FIG. 7, the moving object 10 emits a light beam 20L. 2b If the reflected light beam is not irradiated at , the reflected light beam will not return. Below, the periods in which the measurement distance and measurement speed exhibit characteristic behavior will be explained, divided into periods I to VI.

[0094] In period I, the moving object 10 transmits the light beam 20L 2b In period I, the measured distance decreases over time in period II, and the measured distance remains almost constant over time in period III. In period II, the front surface of the moving object 10 is irradiated with the light beam 20L from the back to the front. 2b In period III, the side surface of the moving body 10 is irradiated with the light beam 20L from the front end to the rear end. 2b From the measured distance, it is possible to determine the irradiation period for the front or side of the moving object 10. Note that in the examples shown in FIGS. 4A and 4B, period II is omitted.

[0095] In period I, the measured speed in periods IV and V is higher than the measured speed in other periods. Although there are differences in the magnitude of the measured speed, the measured speed in periods IV and V and other periods is almost constant. In period III, in periods IV and V, the wheels of the moving object 10 are in contact with the light beam 20L. 2b The period VI between them is a period in which the side of the body of the moving body 10 located between the two wheels is irradiated with the light beam 20L. 2b From the measured speed, the irradiation period of the body and wheels of the moving object 10 can be determined.

[0096] Within period I, the measured speeds in periods IV and V are higher than the measured speeds in other periods by the first term on the right side of equation (2). Using equation (1), the running speed V of the moving object 10 can be calculated from the measured speeds in periods other than periods IV and V.

[0097] Various attribute data regarding the moving object 10 can be obtained from the measured distance data and measured speed data shown in Fig. 7. D , the traveling speed V of the moving object 10, and the light beam 20L 2b From the irradiation angle φ, the width of the moving object 10, that is, the vehicle width D=VΔt D / tanφ can be calculated. L And from the traveling speed V of the moving body 10, the vehicle length L = VΔt L The time span Δt in period IV can be calculated. T1 , time width Δt in period V T2 , time width Δt in period VI T3 , and the traveling speed V of the moving body 10, the distance between the centers of the two wheels, that is, the wheel-to-wheel distance T=V(Δt T1 / 2+Δt T2 / 2+Δt T3 ) can be calculated. The number of rotating wheels can be counted from the difference in the measured speed between the vehicle body and the rotating wheels.

[0098] In the example, one light beam 20L 2b However, by emitting a plurality of light beams 20L2b, the vehicle height can be known.

[0099] Furthermore, attribute data such as vehicle length, width, height, number of rotating wheels, and wheel-to-wheel distance can be used to identify vehicle types on expressways, such as light vehicles, standard vehicles, medium-sized vehicles, large vehicles, and extra-large vehicles.

[0100] Next, with reference to FIGS. 8A to 8C, an example of outputting real-time information about the passage of a moving object 10 as a pulse signal will be described. FIG. 8A is a diagram schematically illustrating an example of outputting vehicle detection and axle detection as pulse signals. A pulse signal corresponding to period I, in which the measured distance and measured speed are non-zero, is output as a vehicle detection pulse signal. When period I ends, it is determined that the moving object 10 has passed. Similarly, pulse signals corresponding to periods IV and V, in which the measured speed becomes relatively high due to the rotating wheels, are output as axle detection pulse signals. In the example shown in FIG. 8A, the vehicle detection and axle detection pulse signals are output synchronously from the different output ports 70 shown in FIGS. 1A and 1B. Synchronized output allows the vehicle detection and axle detection pulse signals to be synchronized. In the example shown in FIG. 8A, a voltage pulse signal is output, but a current or resistance pulse signal may also be output.

[0101] Multiple attribute data may be superimposed and output as a single pulse signal. FIG. 8B is a diagram schematically illustrating an example in which the vehicle detection and axle detection pulse signals of FIG. 8A are superimposed and output. If the voltage value of the pulse signal is V1 or greater, it can be determined that a moving object has been detected, and if the voltage value is V2, it can be determined that a rotating axle has been detected. The voltage value V2 is greater than the voltage value V1. As shown in FIG. 8B, multiple attribute data can be collectively expressed as a single signal by changing the voltage value.

[0102] Attribute data obtained by utilizing the fact that the measured speed has not only positive values ​​but also negative values ​​may be output as a pulse signal. FIG. 8C is a diagram schematically illustrating an example in which the detection of entry and reverse driving of a moving object 10 are output as pulse signals. FIG. 8C illustrates the state in which the moving object 10 is entering and the state in which the moving object 10 is driving in the wrong direction. A pulse signal corresponding to a period in which the measured distance is non-zero is output as a pulse signal for the detection of entry of the moving object 10. A pulse signal corresponding to a period in which the measured speed is negative is output as a pulse signal for the detection of reverse driving of the moving object 10. Outputting the detection of entry and the detection of reverse driving as separate pulse signals makes it easier to process the attribute data in a downstream system. For example, when a moving object 10 enters a lane and passes through, normal processing is performed, whereas when the moving object 10 drives in the wrong direction within the lane, exceptional processing is performed. In such a case, by outputting the detection of entry and the detection of reverse driving as different pulse signals, a system can be constructed that can take different actions depending on whether the moving object 10 passes through or drives in the wrong direction. As described above, various attribute data related to the moving object 10 can be acquired from the measurement data of the moving object 10. Specifically, the attribute data may be at least one selected from the group consisting of vehicle length, vehicle width, vehicle height, number of axles, wheel-to-wheel distance, vehicle type, vehicle passing, vehicle detection, axle detection, entry detection, and wrong-way driving detection. By outputting the attribute data and the distance and speed data that form the basis of the attribute data from different output ports depending on the case, multiple attribute data can be processed in parallel in a downstream system, making it easier to build a system. As such, in the measurement device 100 according to this embodiment and the measurement device 110 according to the modified example, it may be desirable to output multiple attribute data, distance data, and speed data separately from multiple output ports 70.

[0103] The measuring device 100 may be provided above the moving body 10 instead of beside it. Next, referring to Figs. 9A and 9B, when the moving body 10 is irradiated with a plurality of light beams 20L from above, 2b 9A and 9B show an example in which a moving object 10 is irradiated with a plurality of light beams 20L from above. 2b9B is a front view and a side view showing an example in which a plurality of light beams 20L are irradiated. 2b overlap each other to form a single light beam of 20L 2b The multiple reflected light beams 20L are shown as 3b 9A and 9B, the upper surface of the moving body 10 is exposed to a plurality of light beams 20L. 2b The upper surface of the moving body 10 is the portion of the moving body 10 that can be seen when viewed from the +Y direction, that is, when viewed from above. The angle φ shown in FIG. 9B is the angle of the light beam 20L 2b represents the angle between the YZ plane and the light beam 20L. The angle φ can have not only a positive value but also a negative value. When the angle φ is a positive value, the light beams 20L 2b are emitted from the front toward the moving body 10, and when the angle φ is a negative value, a plurality of light beams 20L 2b are emitted from the rear toward the moving body 10. In the example shown in FIG. 9B, the absolute value of the angle φ may be, for example, greater than 0° and equal to or less than 85°. A more preferable absolute value of the angle φ may be equal to or greater than 5° and equal to or less than 30°. 2b are parallel to the XY plane. 2b The light beams 20L are located in a plane perpendicular to the XY plane and intersect with the YZ plane at an angle φ. 2b The multiple channels from which the respective beams are emitted are aligned in a line along a direction perpendicular to the XY plane.

[0104] As shown in FIG. 9A, a plurality of light beams 20L are projected from above. 2b A plurality of reflected light beams 20 are generated by emitting L3b 9B, the width of the moving object 10 and the height of the irradiated portion of the moving object 10 relative to the road surface in the width direction of the moving object 10 can be known. 2b The height of the irradiated point relative to the road surface is h, and the light beam 20L from the measuring device 100 2bThe height of the emitted point relative to the road surface is H, and the distance between the irradiated point and the emitted point is L. In this case, the height h of the irradiated point relative to the road surface is expressed by the following equation (5).

number

[0105] In the example shown in FIGS. 9A and 9B, the hood, windshield, roof, rear window, and trunk of the vehicle 10 emit a plurality of light beams 20L. 2b The maximum height of the multiple irradiation points relative to the road surface is the vehicle height. Light beam 20L 2b Since the roof of the vehicle 10 can be illuminated with the light beam 20L, the vehicle height can be accurately determined. 2b The light beam emitted from a certain channel is 20L. 2b When the road surface is illuminated with multiple light beams 20L, the height of the illuminated point relative to the road surface is zero. By excluding channels that produce such results, the vehicle width can be determined. 2b is parallel to the XY plane, it is easy to know under which of the multiple channels the moving object 10 has passed.

[0106] Next, referring to FIGS. 10A and 10B, a plurality of light beams 20L in different directions from the above are 2b 10A shows an example in which a moving object 10 is irradiated with a plurality of light beams 20L from the side. 2b 10A is a front view showing another example in which a plurality of light beams 20L are irradiated. 2b The angle θ shown in FIG. 10A is the angle of the plurality of light beams 20L 2b represents the angle formed by each of the light beams 20L and the XZ plane. 2b The plurality of light beams 20L intersect with the YZ plane at an angle φ as shown in FIG. 2bis a plane perpendicular to the XZ plane and intersects with the YZ plane at an angle φ. 2b In the example shown in FIG. 10A, the height of the light beam 20L emitted from the upper channel is expressed by Equation (4). 2b Since the roof of the vehicle 10 can be illuminated with the light beam 20L, the vehicle height can be accurately determined. 2b As mentioned above, the number of rotating axles can be counted in the lower channel.

[0107] FIG. 10B shows the moving object 10 receiving the light beam 20L from above. 2b 10B is a front view showing another example in which a plurality of light beams 20L are irradiated. 2b The angle θ shown in FIG. 10B is the angle of the light beam 20L. 2b and the XZ plane. 2b The light beams 20L intersect the YZ plane at an angle φ as shown in FIG. 2b The light beams 20L are located in a plane perpendicular to the XY plane and intersect with the YZ plane at an angle φ. 2b When the light beams 20L are parallel to the XY plane as shown in FIG. 9A, θ+φ=90°. 2b is non-parallel to the XY plane as shown in FIG. 10B, then θ+φ≠90°.

[0108] In the example shown in FIG. 10B, the moving object 10 emits a light beam 20L 2b The height of the irradiated point relative to the road surface is h, and the light beam 20L from the measuring device 100 2b The height of the emitted point relative to the road surface is H, and the distance between the irradiated point and the emitted point is L. In this case, the height h of the irradiated point relative to the road surface is expressed by the following equation (6).

number

[0109] The moving object 10 receives a light beam 20L from above. 2b When illuminated with multiple light beams 20L 2b 10B, the height of the light beam 20L emitted from the channel near the right end as viewed from the -X direction can be known even if the light beam 20L is not parallel to the XY plane. 2b It can illuminate the rotating wheels, allowing you to count the number of rotating axles.

[0110] In the example shown in FIGS. 10A and 10B, multiple light beams 20L 2b The emission directions of the multiple light beams 20L do not all need to be the same. 2b The emission directions of some of the light beams 20L may be different from the emission directions of the remaining parts, or all of the emission directions may be different from each other. 2b The processing circuit 60 controls the optical deflector to deflect the plurality of light beams 20L in accordance with the purpose and application. 2b The emission directions of some or all of the light beams may be changed.

[0111] Next, an example of a measurement operation performed by the processing circuit 60 will be described with reference to Fig. 11. Fig. 11 is a flowchart showing an example of a measurement operation performed by the processing circuit 60. When the moving object 10 enters a lane, the processing circuit 60 performs the following operations from steps S101 to S107.

[0112] <Step S101> The processing circuit 60 causes the light source 20 to emit the laser light 20L0 while changing the frequency of the laser light 20L0.

[0113] <Step S102> The processing circuit 60 causes the photodetector 50 to detect the interference light 20L4. The photodetector 50 outputs a signal corresponding to the intensity of the interference light 20L4.

[0114] <Step S103> The processing circuit 60 generates, for each channel, data relating to the distance from the measuring device 100 to the moving object 10 and data relating to the speed of the moving object 10 based on the signal output from the photodetector 50. 3b reach the photodetector 50 at different times, it is possible to determine which part of the time change of the interference light 20L4 corresponds to which channel.

[0115] <Step S104> The processing circuit 60 outputs data related to distance and / or velocity from the first output port 70a shown in FIG. 1A or 1B. For example, data related to distance and velocity for multiple channels at a certain time is output sequentially from the first output port 70a. In the example shown in FIGS. 4A and 4B, the measured distance of ch.1, the measured velocity of ch.1, the measured distance of ch.2, the measured velocity of ch.2, the measured distance of ch.3, and the measured velocity of ch.3 at a certain time are output in this order from the first output port 70a.

[0116] <Step S105> The processing circuit 60 determines whether the moving object 10 has passed in front of the measurement device 100. In a configuration in which a beam damper is not installed, if the measured velocity is zero and the measured distance is longer than a predetermined distance for all channels, the processing circuit 60 can determine that the moving object 10 has passed in front of the measurement device 100. Alternatively, in a configuration in which a beam damper is installed, if the measured velocity is zero and the measured distance is longer than a predetermined distance for all channels, the processing circuit 60 can determine that the moving object 10 has passed in front of the measurement device 100. 3b If the determination is Yes, the processing circuit 60 proceeds to step S10. 6 If the determination is No, the processing circuit 60 executes the operation of step S101 again.

[0117] <Step S106> The processing circuit 60 generates a plurality of attribute data relating to the moving object 10 based on measurement data of the moving object 10 obtained by processing the signal output from the photodetector 50. Body 1 The generation of the attribute data of 0 is as described with reference to FIG.

[0118] <Step S107> The processing circuit 60 outputs attribute data 1 and 2 from the plurality of attribute data as pulse signals from the second output port 70b and the third output port 70c shown in FIG. 1A or 1B, respectively. The attribute data 1 and 2 may be data indicating, for example, vehicle length and vehicle height, respectively. By associating the vehicle length with a voltage value, the vehicle length can be determined from the voltage value of the pulse signal. The same applies to vehicle length, vehicle width, vehicle height, number of axles, wheel-to-wheel distance, and vehicle type. The attribute data may be time-independent data such as vehicle length, vehicle height, vehicle width, and wheel-to-wheel distance, or may be time-dependent data such as the vehicle detection and wheel detection pulse signals shown in FIGS. 8A and 8B and the entry detection and wrong-way driving detection pulse signals shown in FIG. 8C.

[0119] Note that processing circuitry 60 may not perform the operation of step S104. Alternatively, processing circuitry 60 may perform the operation of generating time-series data regarding distance and / or speed and outputting the data from the first output port after step S105, S106, or S107.

[0120] The processing circuitry 60 may output the attribute data to, for example, a display device, which displays the attribute information about the moving object 10. In this case, the output information included in the data output by the processing circuitry 60 matches the display information displayed on the display device.

[0121] Alternatively, the processing circuitry 60 may output the measurement data used to generate the attribute data to another terminal. The other terminal includes a processing circuit and a display device. The processing circuit of the other terminal generates attribute data based on the measurement data and outputs it to the display device, and the display device displays the attribute information related to the moving object 10. In this case, the output information included in the data output by the processing circuitry 60 is different from the display information displayed on the display device.

[0122] As described above, the measurement device 100 according to this embodiment and the measurement device 110 according to the modification can generate a plurality of attribute data related to the moving object 10 using a single housing. 2b Furthermore, in the measurement devices 100 and 110, a plurality of reflected light beams 20L 3b By utilizing the fact that the reflected light beams 20L return at different times, 3b can be individually detected by a single photodetector 50.

[0123] Next, with reference to FIG. 12, an example in which the processing circuit 60 generates data relating to the vehicle length, vehicle height, and number of axles from the attribute data described above will be described. FIG. 12 is a flowchart showing another example of the measurement operation performed by the processing circuit 60. The flowchart shown in FIG. 12 is simpler than the flowchart shown in FIG. 11. When the moving object 10 enters a lane, the processing circuit 60 performs the following operations of steps S101 to S103, S105, and S108. The operations of steps S101 to S103 and S105 shown in FIG. 12 are the same as the operations of steps S101 to S103 and S105 shown in FIG. 11.

[0124] <Step S108> The processing circuit 60 generates and outputs data related to some or all of the vehicle length, vehicle height, and number of axles based on the signal output from the photodetector 50. In this specification, "data related to some or all of the vehicle length, vehicle height, and number of axles" refers not only to some or all of the numerical data related to the vehicle length, vehicle height, and number of axles, but also to the measurement data used to generate the numerical data. The measurement data may be, for example, time-lapse data related to the distance from the measurement device 100 to the moving object 10 and / or time-lapse data related to the speed of the moving object 10 for all channels, as shown in FIGS. 4A and 4B .

[0125] In the measurement device 100 according to this embodiment and the measurement device 110 according to the modification, one light beam 20L is generated as follows. 2b 9A and 9B, when the moving object 10 is made to travel on the center line of the lane, one light beam 20L is irradiated from above the moving object 10 to determine the vehicle length and height. 2b 4A and 4B, the moving object 10 is irradiated with one light beam 20L of ch.2 from the side, thereby generating data relating to the vehicle length and height. 2b By illuminating the light at ch.2, it can be seen that the vehicle length is equal to or greater than the length of the moving object 10 measured at ch.2, and that the vehicle height is equal to or greater than the height of ch.2 relative to the road surface. In this specification, "data related to vehicle length" refers not only to data indicating the maximum length of the moving object 10, but also to data indicating that the vehicle length is equal to or greater than a certain length. Similarly, "data related to vehicle height" refers not only to data indicating the maximum height of the moving object 10 relative to the road surface, but also to data indicating that the vehicle height is equal to or greater than a certain height.

[0126] Next, an example of installation of the measuring device 100 in ETC will be described with reference to Figures 13A and 13B. Figures 13A and 13B are diagrams that schematically show an example of installation of the measuring device 100 in ETC. Figures 13A and 13B show a mobile object 10 traveling in an ETC lane.

[0127] 13A, the measuring device 100 is installed at the side of the lane. In the example shown in FIG. 13A, the moving body 10 receives a plurality of light beams 20L emitted from the measuring device 100. 2b In the example shown in FIG. 13B, the measurement device 100 is installed at a gate of a lane. The moving object 10 passes through the gate. In the example shown in FIG. 13B, the moving object 10 receives the plurality of light beams 20L emitted from the measurement device 100. 2b 13A and 13B, the moving object 10 is irradiated with a plurality of light beams 20L 2b The measuring device 100 may be installed at any position in the ETC as long as it can irradiate the area. The measuring device 100 may also be installed away from the lanes.

[0128] The moving object to be measured in this embodiment does not have to be a vehicle traveling on a road surface, but may be any moving object. Next, an example of a moving object other than a vehicle will be described with reference to FIG. 14. FIG. 14 is a diagram schematically showing the positional relationship between a belt conveyor 16, a plurality of cardboard boxes 18 carried by the belt conveyor 16, and the measuring device 100. The white arrow shown in FIG. 14 indicates the direction in which the belt conveyor 16 moves. In the example shown in FIG. 14, a plurality of cardboard boxes 18 positioned on the surface of the belt conveyor 16 are detected by a plurality of light beams 20L emitted from the measuring device 100. 2b By illuminating moving objects in a factory, such as cardboard boxes and parts, with at least one light beam, attribute data can be generated, such as the moving object's size (length, width, height, etc.), classification based on size detection, and inspection results based on surface shape measurement. Such attribute data can be useful, for example, for inspection in a factory. [Industrial Applicability]

[0129] The measuring device according to the present disclosure can be used, for example, for vehicle detection in ETC and for inspection in factories. [Explanation of symbols]

[0130] 10 Mobile 12 Obstacles 14 wheels 14a wheels 14b tires 16 conveyor belt 18 Cardboard 20 light source 20L0 laser light 20L1 reference light 20L2 output light 20L 2b Light beam 20L 3b Reflected Light Beam 20L4 interference light 30 Interference Optical System 32 First Fiber Splitter 34 Second Fiber Splitter 36 Optical Circulator 40 Optical splitter 42 Optical Fiber 44 Collimating Lens 50 Photodetector 60 Processing circuit 62 memory 100 Measuring Equipment

Claims

1. A light source that emits laser light for irradiating a vehicle and is capable of changing the frequency of the laser light; an interference optical system that separates the laser light into a reference light and an output light, and causes at least one reflected light beam generated by reflecting at least one light beam obtained from the output light by the vehicle to interfere with the reference light, thereby generating interference light; a photodetector for detecting the interference light; a processing circuit that processes a signal output from the photodetector; the processing circuit generates and outputs a plurality of attribute data related to the vehicle based on the measurement data of the vehicle obtained by processing the signal; The plurality of attribute data includes at least one piece of information selected from the group consisting of the passage of the vehicle, the size of the vehicle, the number of axles of the vehicle, the traveling speed of the vehicle, the traveling direction of the vehicle, and the type of the vehicle. Measuring equipment.

2. the measurement data includes distance data and speed data, and the plurality of attribute data are generated based on the distance data and speed data. The measurement device according to claim 1 .

3. The plurality of attribute data includes at least one piece of information of the number of rotating axles of the vehicle and the traveling speed of the vehicle. The measurement device according to claim 1 .

4. the plurality of attribute data are output as at least one pulse signal; The measuring device according to any one of claims 1 to 3.

5. the at least one pulse signal includes a plurality of pulse signals; a plurality of output ports for outputting the plurality of pulse signals, respectively; The measuring device according to claim 4.

6. The plurality of pulse signals are output in synchronization. The measurement device according to claim 5 .

7. the at least one pulse signal is one pulse signal; the plurality of attribute data are superimposed on the single pulse signal and output. The measuring device according to claim 4.

8. the emission direction of the at least one light beam is oblique to the direction of travel of the vehicle; The measuring device according to any one of claims 1 to 7.

9. the at least one light beam comprises a plurality of light beams; the at least one reflected light beam includes a plurality of reflected light beams equal in number to the plurality of light beams; an optical branching unit including a plurality of output ports, branching the output light and emitting the light from each of the plurality of output ports; each of the plurality of light beams corresponds to the light emitted from one of the plurality of exit ports included in the optical splitter; The measuring device according to any one of claims 1 to 8.

10. the vehicle is illuminated from the sides with the plurality of light beams; The measurement device according to claim 9.

11. the plurality of light beams are emitted from different heights relative to a surface on which the vehicle is located; The measurement device according to claim 10.

12. the plurality of light beams are parallel to the surface; The measurement device according to claim 11.

13. the vehicle includes a wheel; One or more of the plurality of light beams are emitted toward the wheel. The measurement device according to claim 11.

14. Among the plurality of light beams, one or more light beams are non-parallel to the surface, and the remaining light beams are parallel to the surface. The measurement device according to claim 13.

15. the vehicle is illuminated from above with the plurality of light beams; The measurement device according to claim 9.

16. the plurality of light beams are parallel to a plane perpendicular to a surface on which the vehicle is located and parallel to a direction of travel of the vehicle; The measurement device according to claim 15.

17. a light source that emits a laser beam for irradiating a vehicle on a road surface and is capable of changing the frequency of the laser beam; an interference optical system that separates the laser light into a reference light and an output light, and generates interference light by causing a plurality of reflected light beams generated by reflecting a plurality of light beams obtained from the output light by the vehicle to interfere with the reference light; an optical branching device including a plurality of exit ports that branches the output light and emits the plurality of light beams from the plurality of exit ports; a photodetector for detecting the interference light; a processing circuit that processes a signal output from the photodetector; the processing circuit generates and outputs data relating to at least one of the length of the vehicle, its height relative to the road surface, and its traveling speed based on the signal output from the photodetector; Measuring equipment.

18. A computer program executed by a computer in a system including a measurement device, The measuring device is a light source that emits a laser beam for irradiating a vehicle and is capable of changing the frequency of the laser beam; an interference optical system that separates the laser light into a reference light and an output light, and causes at least one reflected light beam generated by reflecting at least one light beam obtained from the output light by the vehicle to interfere with the reference light, thereby generating interference light; a photodetector for detecting the interference light; a processing circuit that processes a signal output from the photodetector; the computer program causes the computer to generate and output a plurality of attribute data related to the vehicle based on measurement data of the vehicle obtained by processing the signal; The plurality of attribute data includes at least one piece of information selected from the group consisting of the passage of the vehicle, the size of the vehicle, the number of axles of the vehicle, the traveling speed of the vehicle, the traveling direction of the vehicle, and the type of the vehicle. Computer program.

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