JP2023067922A - Device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the measurement accuracy by reducing noise caused by weather in a distance measuring device using light reflection.

SOLUTION: An output part 110 outputs a plurality of lights, each of which has a different peak wavelength. An acquisition part 120 acquires a reflection pattern, which is an intensity waveform of reflected light, for each of the plurality of lights. Based on a plurality of reflection patterns, a processing part 130 identifies a component caused by weather contained in at least one of the plurality of reflection patterns. A distance calculation part 150 calculates the distance between a distance measuring device 10 and an object to be irradiated with light.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to a distance measuring device and a distance measuring method.

2. Description of the Related Art In recent years, development of non-contact distance measuring devices that can be used for automatic driving of automobiles and the like has been carried out. A non-contact distance measuring device measures the time it takes for emitted light to be reflected by an object and return to measure the distance to surrounding objects. Here, noise may occur in the reflected light depending on the weather.

For example, Patent Literature 1 describes an apparatus that irradiates a laser beam to an object whose distance is known and determines the weather based on received light waveform data of reflected light.

Further, for example, in Patent Document 2, near-infrared light in a wavelength range with a large amount of absorption by water and near-infrared light in a wavelength range with a small amount of absorption by water are projected, and the intensity of each near-infrared light is adjusted. A technique is described for distinguishing between snow, sleet, and rain based on the variation value. Specifically, in the technique of Patent Document 2, a variation value equal to or greater than a threshold value is set as an effective value, effective values for each wavelength are compared and calculated as a determination value, and the determination value is compared with a reference value for determination.

JP 2015-52465 A JP 2013-122413 A

However, the techniques disclosed in Patent Documents 1 and 2 cannot reduce weather-derived noise in the reflection intensity waveform.

One example of the problem to be solved by the present invention is to reduce weather-derived noise and improve measurement accuracy in a distance measuring device that uses reflection of light.

The first invention is
an output unit that outputs a plurality of lights with different peak wavelengths;
an acquisition unit that acquires a reflection pattern, which is an intensity waveform of reflected light, for each of the plurality of lights;
a processing unit that identifies a component derived from the weather contained in at least one of the plurality of reflection patterns based on the plurality of reflection patterns;
A distance measuring device comprising:

The second invention is
Output multiple lights with different peak wavelengths,
Acquiring a reflection pattern, which is an intensity waveform of reflected light, for each of the plurality of lights;
A distance measurement method for identifying a component derived from weather contained in at least one of the plurality of reflection patterns, based on the plurality of reflection patterns.

2 is a block diagram illustrating the functional configuration of the distance measuring device according to the first embodiment; FIG. It is a figure which illustrates the structure and usage environment of the distance measuring device which concerns on 1st Embodiment. FIG. 4 is a diagram showing an example of a reflection pattern; 3 is a block diagram illustrating the functional configuration of a processing unit according to the first embodiment; FIG. 4 is a flowchart of a distance measurement method according to the first embodiment; 6 is a flow chart illustrating the contents of processing performed by a processing unit in the first embodiment; FIG. 4 is a diagram showing a first example of multiple reflection patterns; FIG. 10 is a diagram showing a second example of multiple reflection patterns; 9 is a flow chart showing a modification of the contents of processing performed by the processing unit in the first embodiment; FIG. 7 is a block diagram illustrating the functional configuration of a distance measuring device according to a second embodiment; FIG. FIG. 8 is a block diagram illustrating the functional configuration of a processing unit according to the second embodiment; 8 is a flow chart of a distance measurement method according to the second embodiment; FIG. 11 is a block diagram illustrating the functional configuration of a processing unit according to the third embodiment; FIG. 10 is a flow chart showing details of a process for specifying components derived from weather according to the third embodiment. FIG. 12 is a block diagram illustrating the configuration of a distance measuring device according to a fourth embodiment; FIG. It is a figure which shows the use environment of the distance measuring device which concerns on 4th Embodiment. It is a block diagram which illustrates the functional structure of a server.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in all the drawings, the same constituent elements are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

In the following description, the output unit 110, the acquisition unit 120, the processing unit 130, the distance calculation unit 150, the storage unit 140, the matching peak extraction unit 132, the matching peak number determination unit 134, the identification unit 136, the weather The information acquisition unit 160, the weather determination unit 138, the communication unit 170, the communication unit 610, the selection unit 620, and the storage unit 630 show blocks in units of functions rather than in units of hardware. The acquisition unit 120, the processing unit 130, the distance calculation unit 150, the storage unit 140, the matching peak extraction unit 132, the matching peak number determination unit 134, the identification unit 136, the weather information acquisition unit 160, the weather determination unit 138, The communication unit 170, the communication unit 610, the selection unit 620, and the storage unit 630 are mainly composed of a CPU of an arbitrary computer, a memory, a program loaded in the memory, a storage medium such as a hard disk storing the program, and an interface for network connection. It can be implemented by any combination of hardware and software. There are various modifications of the implementation method and device.

(First embodiment)
FIG. 1 is a block diagram illustrating the functional configuration of a distance measuring device 10 according to the first embodiment. The distance measuring device 10 according to this embodiment includes an output unit 110, an acquisition unit 120, and a processing unit . The output unit 110 outputs a plurality of lights with different peak wavelengths. Acquisition unit 120 acquires a reflection pattern, which is an intensity waveform of reflected light, for each of a plurality of lights. Based on the plurality of reflection patterns, the processing unit 130 identifies the component derived from the weather contained in at least one of the plurality of reflection patterns.

Further, the distance measuring device 10 according to the present embodiment further includes a distance calculator 150 that calculates the distance between the distance measuring device 10 and the target object irradiated with light. A distance calculation unit 150 generates a corrected reflection pattern by subtracting a component derived from the weather from at least one reflection pattern, and calculates a distance based on the corrected reflection pattern. Furthermore, the distance measuring device 10 includes a storage unit 140 in the example of this figure.

FIG. 2 is a diagram illustrating the configuration and usage environment of the distance measuring device 10 according to this embodiment. Each component of the distance measuring device 10 will be described in detail below with reference to FIGS. 1 and 2. FIG. In FIG. 2, multiple lights are indicated by solid line arrows and dashed line arrows. Hereinafter, the light indicated by the solid line arrow is called the first light, and the light indicated by the broken line arrow is called the second light.

The distance measuring device 10 is a device that measures the distance from the distance measuring device 10 to the target object 20 . A plurality of lights emitted from output unit 110 (for example, laser light source 810 ) of distance measuring device 10 are reflected by target object 20 and return toward distance measuring device 10 . Then, the reflected light enters the first light receiving element 850a and the second light receiving element 850b, and the intensity of the reflected light is detected. Here, the distance measuring device 10 measures the time from when the light is emitted from the output section 110 until when the reflected light is detected. Then, the obtaining unit 120 obtains the information indicating the relationship between the time and the reflected light intensity as the information indicating the reflection pattern. A peak derived from reflected light reflected by the target object 20 appears in the reflection pattern. Then, by multiplying the time from when the light is emitted from the output unit 110 until the reflected light is incident on the first light receiving element 850a and the second light receiving element 850b by the speed of light, the distance measurement device 10 can detect the target object. Round trip distances up to 20 are calculated. The peak position in the reflection pattern corresponds to the time from when the light is emitted from the laser light source 810 until the reflected light is incident on the first light receiving element 850a and the second light receiving element 850b. Corresponds to the distance to the reflected object. Distance measuring device 10 is, for example, a LIDAR (Laser Imaging Detection and Ranging) device.

Output unit 110 is, for example, laser light source 810 . Also, the light output by the output unit 110 is pulsed light. The output unit 110 outputs a plurality of lights with different peak wavelengths. The peak wavelength of the first light is the first wavelength and the peak wavelength of the second light is the second wavelength. Here, the peak wavelength is the wavelength showing the maximum intensity peak in the spectrum of each light. The first wavelength and the second wavelength are wavelengths different from each other. The light of the first wavelength is, for example, visible light, and the first wavelength is, for example, 380 nm or more and 800 nm or less. Moreover, the light of the second wavelength is, for example, near-infrared light, and the second wavelength is, for example, 800 nm or more and 2500 nm or less. However, the light of the first wavelength may be near-infrared light. Specifically, a semiconductor laser or the like that emits light with a wavelength of 780 nm can be used as the light source of the first light. A semiconductor laser with a wavelength of 820 nm or the like can be used as the light source of the second light. A plurality of peak wavelengths of light are separated from each other by, for example, 50 nm or more.

Alternatively, a semiconductor laser emitting light with a wavelength of 780 nm or 820 nm may be used as the light source of the first light, and a semiconductor laser with a wavelength of 980 nm may be used as the light source of the second light. Snow spectroscopy shown in "Effect of Snow Reflection on Solar Cell Power Generation" (The bulletin of Laboratory for Energy, Environment and Systems, Hachinohe Institute of Technology 10, 29-34, March 30, 2012) In light of the reflection characteristics, by setting the first wavelength and the second wavelength to such wavelengths, noise can be reduced with higher accuracy. On the other hand, light scattering varies in size depending on the relationship between particle size and wavelength. is preferably the first wavelength and the second wavelength.

Also, the optical axes of the first light and the second light are substantially aligned. However, in this figure, for the sake of convenience, the optical axes of the solid-line arrows and the broken-line arrows are shifted from each other. As the output unit 110, as in the example of FIG. 2, a light source packaged so as to output a plurality of lights with different peak wavelengths, such as a dual-wavelength output laser diode, can be used. Note that the output unit 110 may be configured using a plurality of light sources that output one light, without being limited to the example of this figure. In this case, a dichroic mirror, a polarizing prism, a half mirror, or the like can be used to align the optical axes of the plurality of lights and output them to the outside of the distance measuring device 10 .

A plurality of pulsed lights having different peak wavelengths are simultaneously output from the laser light source 810 . The timing of the output of laser light source 810 is controlled by controller 812 . Controller 812 controls laser light source 810 based on an input signal from information processing device 870 . The information processing device 870 is a computer including, for example, a CPU, a memory, a program loaded in the memory, a storage medium such as a hard disk for storing the program, an interface for network connection, and the like.

Light output from laser light source 810 is output to the outside of distance measuring device 10 via collimator lens 814 and half mirror 830 . Then, it is reflected by the target object 20 and returns to the distance measuring device 10 . The timing, direction and position of the multiple light outputs from the distance measuring device 10 are substantially the same. At least part of the light that has returned to the distance measuring device 10 is guided through the half mirror 830 and the detection side lens 852 to the first light receiving element 850a and the second light receiving element 850b. The first light receiving element 850a and the second light receiving element 850b are photodiodes, for example. The first light receiving element 850a and the second light receiving element 850b may be the same element, or may have different detectable wavelength bands so that the first light and the second light can be effectively detected. good.

A polarizing beam splitter may be used instead of the half mirror 830 . In the example of FIG. 2, the acquisition unit 120 is realized by at least the first light receiving element 850a, the second light receiving element 850b, the detection circuit 853, and the information processing device 870. FIG. A first filter 851 a is provided between the first light receiving element 850 a and the detection side lens 852 , and a second filter 851 b is provided between the second light receiving element 850 b and the detection side lens 852 . The first filter 851a is an optical filter that transmits light of a first wavelength and suppresses the transmission of light of other wavelengths, and the second filter 851b transmits light of a second wavelength and transmits light of other wavelengths. It is an optical filter that suppresses the For example, the transmittance of the first filter 851a for the light of the first wavelength is 90% or more, and the transmittance of the light of the second wavelength is 50% or less. The second filter 851b has a transmittance of 90% or more for light of the second wavelength, and a transmittance of 50% or less for light of the first wavelength.

The first light and the second light can enter both the first filter 851a and the second filter 851b. However, the first light preferentially enters the first light receiving element 850a through the first filter 851a, and the second light preferentially enters the second light receiving element 850b through the second filter 851b. incident on Therefore, the reflected light of the first light and the reflected light of the second light can be separately detected by the first light receiving element 850a and the second light receiving element 850b.

Note that the configuration of the distance measuring device 10 is not limited to the example of FIG. 2 as long as the reflected light of the first light and the reflected light of the second light can be individually detected. For example, instead of using the first filter 851a and the second filter 851b, a dichroic mirror may be used to separate a plurality of lights with different peak wavelengths, and each light receiving element may detect them. Also, although FIG. 2 shows an example in which the first filter 851a and the second filter 851b are provided adjacent to each other, the present invention is not limited to this example. For example, light in which the first light and the second light are mixed may be separated into a plurality of optical paths by a half mirror, and then made incident on optical filters and light-receiving elements having different transmission wavelengths.

Also, the optical system of the distance measuring device 10 may have the same configuration as that of an optical disk pickup. That is, the p-polarized light that has passed through the polarizing prism is emitted to the outside of the distance measuring device 10 via the 1/4 λ plate. Then, the reflected light reflected by the object 20 or the like is passed through a 1/4λ plate to be converted to s-polarized light, and reflected by a polarizing prism, so theoretically 100% light quantity can be detected. For two wavelengths, it is possible to appropriately calculate and design a suitable wave plate.

When using any optical system, it is important to design equal distances from the light source to the target object and from the target object to the light receiving element for the two wavelengths.

When light is incident on the first light receiving element 850 a and the second light receiving element 850 b , an electrical signal corresponding to the intensity of the incident light is generated by the detection circuit 853 and input to the information processing device 870 . Then, in the information processing device 870, the intensity of received light is associated with time. Thus, the acquisition unit 120 acquires reflection patterns for each of the plurality of lights. Here, the reflection pattern indicates the intensity waveform of the reflected light. Note that the intensity waveform indicates the relationship between the time from when the light is emitted from the output unit 110 until the reflected light is detected and the intensity of the reflected light.

For example, between the first light receiving element 850a and the second light receiving element 850b and the detection side lens 852, gate means is provided so that the light reflected by the target object 20 is detected only when it is expected to be incident. may By doing so, it is possible to reduce noise caused by external light and reflected light from an object other than the target object 20 .

Here, when the distance measurement device 10 measures the distance outdoors, if the particles 22 are suspended between the distance measurement device 10 and the target object 20 due to rain, fog, snow, or the like, it causes noise. That is, the light output from the output unit 110 hits the particles 22 before reaching the target object 20 and is reflected or scattered. The reflected light reflected by the particles 22 also enters the first light receiving element 850a and the second light receiving element 850b and is reflected in the reflection pattern. Then, noise peaks other than the target peak derived from the target object 20 appear in the reflection pattern, and it is difficult to distinguish between them.

FIG. 3 is a diagram showing an example of a reflection pattern. In the example of this figure, the reflection pattern includes a noise peak 41 derived from noise and a target peak 42 derived from the target object 20 . However, in practice, it is unknown which are the noise peaks 41 and which are the target peaks 42 in the reflection pattern. Also, the effect of the weather on the reflection pattern varies with the weather, and the shapes of the noise peak 41 and the target peak 42 can each vary depending on the weather.

As will be described later, in the distance measuring device 10 according to the present embodiment, the processing unit 130 compares peaks appearing in a plurality of reflection patterns obtained using a plurality of lights with different peak wavelengths. Then, the component derived from the weather is specified. By doing so, it is possible to reduce the noise peaks 41 from the reflection pattern and improve the accuracy of the distance measurement.

The processing unit 130 is implemented by the information processing device 870 . Based on the plurality of reflection patterns acquired by the acquisition unit 120, the processing unit 130 identifies the component derived from the weather contained in at least one of the plurality of reflection patterns.

FIG. 4 is a block diagram illustrating the functional configuration of the processing unit 130 according to the first embodiment. In this embodiment, the processing unit 130 includes a matching peak extraction unit 132 , a matching peak number determination unit 134 and an identification unit 136 . The matching peak extraction unit 132 extracts matching peaks having matching positions in a plurality of reflection patterns. A matching peak number determination unit 134 determines the number of matching peaks extracted by the matching peak extraction unit 132 . The identification unit 136 identifies components derived from the weather based on the determination result of the matching peak number determination unit 134 .

Returning to FIGS. 1 and 2, the distance calculation unit 150 is realized by the information processing device 870. FIG. The distance calculation unit 150 generates a corrected reflection pattern by subtracting the component derived from the weather specified by the processing unit 130 from at least one reflection pattern. Then, the distance is calculated based on the corrected reflection pattern. Details of the processing performed by the processing unit 130 and the distance calculation unit 150 will be described later.

FIG. 5 is a flow chart of the distance measurement method according to the first embodiment. This distance measurement method can be implemented by the distance measurement device 10 . In this distance measurement method, a plurality of lights having different peak wavelengths are output (step S10), a reflection pattern, which is the intensity waveform of the reflected light, is acquired for each of the plurality of lights (step S20), and the plurality of reflection patterns Based on this, the component derived from the weather contained in at least one reflection pattern among the plurality of reflection patterns is specified (step S30).

Further, in the distance measurement method according to the present embodiment, a corrected reflection pattern is generated in which weather-derived components are reduced (step S40), and the distance between the distance measurement device 10 and the target object 20 is calculated using the corrected reflection pattern. calculated (step S50). A detailed description is given below.

First, in step S10, the output unit 110 outputs a plurality of lights as described above. Then, in step S20, the acquisition unit 120 acquires a reflection pattern for each of the plurality of lights as described above.

Next, in step S30, the processing unit 130 identifies a weather-derived component in the reflection pattern, for example, as described below.

FIG. 6 is a flow chart illustrating the contents of processing performed by the processing unit 130 in this embodiment. The matching peak extraction unit 132 of the processing unit 130 extracts matching peaks having matching positions in a plurality of reflection patterns (step S310). Specifically, first, in each reflection pattern, the point at which the differential value of the reflected light intensity with respect to time changes from positive to negative is extracted as the peak position. The number of peak positions extracted here may be one or two or more in each reflection pattern. Then, the peak positions of the plurality of reflection peaks are compared to extract matching peaks with matching positions. It should be noted that the matching of the peak positions includes not only the case of complete matching but also the case of different positions within the range of measurement error.

Here, if there is no matching peak, for example, the output unit 110 outputs light again and acquires a plurality of reflection patterns.

Next, the matching peak number determination unit 134 determines the number of matching peaks extracted by the matching peak extraction unit 132 (step S320). For example, the matching peak number determination unit 134 determines whether the number of matching peaks is one or two or more.

Then, the identification unit 136 identifies components derived from the weather based on the determination result of the matching peak number determination unit 134 . Specifically, for example, the identification unit 136 can identify components derived from the weather as follows.

When the number of matching peaks is 1 (Y in step S320), the identifying unit 136 of the processing unit 130 identifies peaks other than the matching peaks among the peaks extracted by the matching peak extraction unit 132 in at least one reflection pattern as weather conditions. is specified as a component derived from (step S330). Here, when the number of matching peaks is 1, it can be said that the positions of the peaks appearing in the reflection patterns match each other only at one position among a plurality of reflection patterns. It can be said that this is the case when there is only one position to be set.

FIG. 7 is a diagram showing a first example of multiple reflection patterns. The upper figure in this figure is the reflection pattern of the first light, and the lower figure is the reflection pattern of the second light. The origin of any reflection pattern is the time when the light is output. In the example of this figure, the number of matching peaks is one. In this case, among the reflection peaks of the reflection patterns in the upper and lower figures, peaks whose positions do not match can be regarded as noise peaks 41 derived from the weather. For example, the probability that the light is diffused by the particles 22 may differ depending on the wavelength of the light, or only one of a plurality of lights may be reflected by the particles 22 due to a slight optical path mismatch. This is because, as a result, the peak positions of the light reflected by the particles 22 may not match in a plurality of reflection patterns. On the other hand, peaks from a sufficiently large target object 20 are considered co-located. Therefore, the identifying unit 136 can identify peaks other than peaks whose positions match as components derived from the weather. Each reflection pattern may have one peak or two or more peaks identified as weather-derived components.

In the reflection pattern, each peak is specified, for example, by the time zone in which the peak appears. Alternatively, each peak may be specified by peak data described below. When each peak is specified by peak data, the information indicating the reflection pattern includes multiple peak data. Each peak data is data indicating one peak of light intensity with respect to time, and may be, for example, a graph, a table, a formula, or the like. Alternatively, each peak data may be a combination of peak position, peak intensity and half width. A reflection pattern is represented by superposition of peaks indicated by a plurality of peak data. By fitting the acquired reflection pattern (intensity waveform) with a predetermined function, peaks can be separated and a plurality of peak data can be generated.

On the other hand, when the number of matching peaks is not 1 (N in step S320), the specifying unit 136 of the processing unit 130 determines that the positions of the peaks appearing in the reflection patterns are different from each other at two or more positions between the plurality of reflection patterns. If they match, among the matching peaks, the peak whose level increases as the peak wavelength of light is longer is specified as a component derived from the weather (step S340).

FIG. 8 is a diagram showing a second example of multiple reflection patterns. The upper figure in this figure is the reflection pattern of the first light, and the lower figure is the reflection pattern of the second light. The origin of any reflection pattern is the time when the light is output. In the example of this figure, the peak wavelength of the first light is assumed to be shorter than the peak wavelength of the second light. In the example of this figure, the number of matching peaks is two. In this case, the coincident peak whose peak intensity (level) increases as the wavelength of light increases can be regarded as the noise peak 41 derived from the weather.

For example, the longer the wavelength of light, the lower the intensity of backscattering by particles 22 . As a result, it is believed that the peak intensity of the light reflected by the particles 22 increases as the wavelength of the light increases. On the other hand, it is considered that the reflectance of light on the target object 20 is less affected by the wavelength of light. In particular, when the reflective surface of the target object 20 is white, the difference in reflectance due to the difference in wavelength is small. As such an example, the distance measuring device 10 is mounted on a moving body such as a vehicle, and detects reflected light from a white license plate of a preceding vehicle, which is another moving body.

Here, comparison of peak intensities among a plurality of reflection patterns is performed using peak intensities normalized for each reflection pattern. For example, when the sum of the peak intensities of all matching peaks in the reflection pattern is I _t and the peak intensity of the target peak is I _o , the value obtained by I _o /I _t is the normalized peak intensity. . Also, peak intensities of coincident peaks are compared between peaks whose peak positions coincide with each other.

Note that if the particle size of the particles 22 is smaller than the wavelengths of the first light and the second light, the longer the wavelength of the light, the smaller the intensity of scattering by the particles 22 may be. If such weather or environment is predicted in advance, the user's switching operation or the like is performed to specify peaks whose level decreases as the wavelength of light increases in step S340 as components derived from the weather. may

When the number of matching peaks is not 1 (N in step S320), the specifying unit 136 may specify peaks other than matching peaks as components derived from the weather, as in step S330.

FIG. 9 is a flow chart showing a modification of the processing performed by the processing unit 130 in this embodiment. As shown in the figure, the identification unit 136 may identify peaks other than the coincident peaks as weather-derived components after the coincident peaks are extracted and before the number of coincident peaks is determined (step S330). . In that case, after step S330, the matching peak number determining unit 134 determines the number of matching peaks (step S320). Then, when the number of matching peaks is 1 (Y in step S320), the identifying unit 136 identifies only the peaks identified in step S330 as components derived from the weather. Then, when the number of matching peaks is not 1 (N in step S320), the identifying unit 136 further identifies peaks whose level increases as the wavelength of light increases as a weather-derived component (step S340).

As described above, the processing unit 130 identifies components derived from the weather. The processing unit 130 outputs, as information indicating weather-derived components in at least one reflection pattern (for example, the first light reflection pattern), the time period in the reflection pattern of the weather-derived peak or the above-described peak data. do.

Returning to FIG. 5, the distance calculation unit 150 then generates a corrected reflection pattern by subtracting the component derived from the weather specified by the processing unit 130 from at least one reflection pattern (step S40). Specifically, the distance calculation unit 150 acquires information indicating components derived from the weather from the processing unit 130 . Then, the peak indicated by the information indicating the component derived from the weather is subtracted from the reflection pattern (for example, the reflection pattern of the first light) in which the component derived from the weather is specified. For example, the distance calculation unit 150 may generate a corrected reflection pattern by setting the intensity of the reflection pattern to zero in a time zone in which a peak derived from weather is located. Further, when the information indicating the component derived from the weather is peak data, the distance calculation section 150 may subtract the peak amount from the reflection pattern to generate the corrected reflection pattern.

Also, when the matching peak is identified as a peak derived from the weather, like the peak identified in step S340, the distance calculator 150 can generate a corrected reflection pattern as follows. Below, as shown in FIG. 8, the case where the noise peak 41 (component derived from the weather) in the first light reflection pattern is smaller than the peak at the same position in the second light reflection pattern will be described. In this case, the overall intensity of the reflection pattern of the second light is multiplied by a predetermined magnification α. Then, the second reflection pattern multiplied by α is subtracted from the first reflection pattern of light. By doing so, it is possible to generate a corrected reflection pattern in which noise peaks 41 are reduced from the reflection pattern of the first light.

Here, the information indicating the magnification α is derived, for example, by a preliminary test or the like from the intensity ratio of the noise peak 41 between the first light and the second light, stored in the storage unit 140, and the distance calculation unit 150 It can be read out and used. Alternatively, using the peak intensity _I1 of the noise peak 41 of the first light and the peak intensity _I2 of the noise peak ₄₁ of _the second light that are aligned with each other, the distance The calculation unit 150 may derive it each time. Here, when there are a plurality of noise peaks 41 having the same position in each reflection pattern, _I1 / _I2 is calculated for each noise peak 41, and the average value thereof can be used as α.

In the above, when the second reflection pattern multiplied by α is subtracted from the first reflection pattern of light, the subtraction is performed only for the time zone in which the noise peak 41 occurs in the first reflection pattern. Also good.

Next, the distance calculator 150 calculates the distance between the distance measuring device 10 and the target object 20 using the corrected reflection pattern (step S50). That is, the maximum peak in the corrected reflection pattern is regarded as the reflection peak from the target object 20, and the time from light emission to detection of the reflection peak is obtained based on the peak position. Then, by multiplying the obtained time by the speed of light, the round-trip distance from the distance measuring device 10 to the target object 20 is calculated.

Note that the output unit 110 may output a plurality of lights multiple times, the acquisition unit 120 may acquire a reflection pattern each time, and the distance calculation unit 150 may generate a plurality of corrected reflection patterns. Then, the distance may be calculated by integrating a plurality of corrected reflection patterns. By doing so, more highly accurate distance measurement becomes possible.

As described above, according to the present embodiment, the output unit 110 outputs a plurality of lights having different peak wavelengths, the acquisition unit 120 acquires a reflection pattern that is the intensity waveform of the reflected light for each of the plurality of lights, and the processing unit Based on the plurality of reflection patterns, 130 identifies weather-derived components in at least one of the plurality of reflection patterns. Therefore, it is possible to reduce noise caused by the weather and improve measurement accuracy.

(Second embodiment)
FIG. 10 is a block diagram illustrating the functional configuration of the distance measuring device 10 according to the second embodiment, and FIG. 11 is a block diagram illustrating the functional configuration of the processing section 130 according to the second embodiment. . The distance measuring device 10 according to the present embodiment is the same as the first embodiment, except that the processing unit 130 identifies components derived from the weather using weather information indicating the weather at the time when the plurality of reflection patterns are acquired. It is the same as the distance measuring device 10 according to the form.

The distance measuring device 10 according to this embodiment further includes a weather information acquisition section 160 . The weather information acquisition unit 160 acquires weather information indicating the weather at the location where the distance measuring device 10 measures the target object 20 at the time the acquisition unit 120 acquires the reflection pattern. Weather information includes information indicating weather such as sunny, rainy, foggy, snowy, and cloudy. Moreover, the weather information may include information indicating photochemical smog and airborne concentration of fine particles in the atmosphere. Weather information acquisition unit 160 can acquire information indicating the weather, for example, via a communication network. Specifically, the weather information can be acquired by accessing the server of the weather information providing service. In addition, the weather information acquisition unit 160 determines the weather based on the information indicating the temperature acquired from the temperature sensor arranged near the distance measuring device 10 and the information indicating the illuminance acquired from the illuminance sensor, and acquires the weather information. You may

The processing unit 130 according to this embodiment also includes a weather determination unit 138 . For example, when the weather is sunny or cloudy, it is considered that noise peaks derived from the weather are less likely to occur. Therefore, in the case of such weather, it is possible to omit the identification of the component derived from the weather and the generation of the corrected reflection pattern, and the processing load of the information processing device 870 can be reduced.

FIG. 12 is a flow chart of the distance measuring method according to this embodiment. In this distance measuring method, the contents of steps S10 and S20 are the same as the method according to the first embodiment. In the distance measurement method according to this embodiment, after step S20, the weather information acquisition unit 160 acquires weather information (step S22).

Next, the weather determination unit 138 of the processing unit 130 determines whether the weather indicated by the acquired weather information satisfies a predetermined criterion. Information indicating the criteria is stored in the storage unit 140 in advance, and the weather determination unit 138 can read it and use it for determination. The standard may be a specific weather such as sunny or cloudy, a standard value for the degree of photochemical smog or the concentration of fine particles suspended in the air, or a combination thereof. .

In the example of this figure, the weather determination unit 138 determines whether the weather is sunny or cloudy (step S24). If the weather information indicates sunny or cloudy (Y in step S24), processing unit 130 does not specify the component derived from the weather. Then, the distance calculation unit 150 calculates the distance similarly to step S50 of the first embodiment using at least one of the plurality of acquired reflection patterns without generating the correction reflection pattern.

If the weather information does not indicate sunny or cloudy (N of step S24), processing unit 130 then identifies components derived from the weather (step S30). The distance calculator 150 then generates a corrected reflection pattern (step S40) and calculates the distance (step S50). Steps S30 to S50 of this embodiment can be performed in the same manner as in the first embodiment.

In addition, the weather determination unit 138 further determines whether the concentration of photochemical smog and fine particles suspended in the air exceeds a reference value, and even if the weather information indicates clear or cloudy, the photochemical smog indicated by the weather information If the concentration of suspended fine particles in the atmosphere exceeds the reference value, the same processing as in the case where the weather information does not indicate sunny or cloudy weather (N in step S24) may be performed. This is because noise peaks may appear as in the case of rain or fog.

As described above, also in this embodiment, the output unit 110 outputs a plurality of lights having different peak wavelengths, the acquisition unit 120 acquires a reflection pattern, which is the intensity waveform of the reflected light, for each of the plurality of lights, and the processing unit 130 specifies a weather-derived component contained in at least one of the plurality of reflection patterns, based on the plurality of reflection patterns. Therefore, it is possible to reduce noise caused by the weather and improve measurement accuracy.

In addition, according to the present embodiment, the processing unit 130 identifies components derived from the weather using weather information indicating the weather at the time when the plurality of reflection patterns are acquired. Therefore, it is possible to specify only when an increase in weather-derived noise is expected, and to reduce the information processing load.

(Third Embodiment)
FIG. 13 is a block diagram illustrating the functional configuration of the processing unit 130 according to the third embodiment. Moreover, FIG. 14 is a flowchart illustrating the details of the process (step S30) of identifying components derived from the weather according to the third embodiment. The distance measuring device 10 according to the present embodiment is the same as the distance measuring device 10 according to the second embodiment, except for the configuration of the processing unit 130 and the processing content in the step of identifying components derived from weather (step S30). is.

For example, if the weather is foggy or rainy, it is likely that noise peaks will occur as coincident peaks. Furthermore, when the weather is snow, the diameter of the particles is large and the distance between the floating particles is also large. Therefore, by using the weather information, it is possible to perform processing suitable for the weather without determining the number of coincident peaks, and to identify components derived from the weather.

The distance measurement method according to this embodiment can be explained using a flowchart similar to that of FIG. 12 . In the distance measurement method of this embodiment, steps other than step S30 are performed in the same manner as in the second embodiment.

In the distance measuring device 10 according to this embodiment, step S30 is performed as follows. First, the matching peak extraction unit 132 extracts matching peaks as in the first embodiment (step S310). Next, the weather determination unit 138 determines whether the weather indicated by the weather information satisfies a predetermined standard. Information indicating the criteria is stored in the storage unit 140 in advance, and the weather determination unit 138 can read it and use it for determination. The standard may be a specific weather such as rain or fog, a standard value for the degree of photochemical smog or the suspended concentration of fine particles in the atmosphere, or a combination thereof. . In the example of this figure, the weather determination unit 138 determines whether the weather indicated by the weather information is fog or rain (step S350).

If the weather is fog or rain (Y in step S350), the identifying unit 136 identifies coincident peaks whose level increases as the wavelength increases as in the first embodiment, as components derived from the weather. (Step S340).

On the other hand, if the weather is neither fog nor rain (N in step S350), the identification unit 136 identifies peaks other than the coincident peak as weather-derived components in the same manner as in the first embodiment (step S330). In addition, the weather determination unit 138 further determines whether the concentration of photochemical smog and fine particles in the atmosphere exceeds a reference value, and even if the weather is not fog or rain, the weather information indicates photochemical smog or When the concentration of suspended fine particles in the atmosphere exceeds the reference value, the same processing as in the case where the weather information indicates fog or rain (Y in step S350) may be performed.

If the weather is foggy or rainy (Y in step S350), the specifying unit 136 may specify peaks other than the matching peak as components derived from the weather, as in step S330.

Further, as a modification of the contents of step S30, the identification unit 136 first identifies peaks other than the coincident peak as components derived from the weather after the coincident peak is extracted, and then the weather determination unit 138 determines the weather. You may Then, if the weather is neither fog nor rain, the identifying unit 136 determines only the already identified peaks as components derived from the weather. Then, if the weather is fog or rain, the identifying unit 136 further identifies peaks whose level increases as the wavelength of light increases as a component derived from the weather.

Also, in this embodiment, in step S350, the weather determination unit 138 may determine whether the weather is snow instead of determining whether the weather is fog or rain. In that case, if the weather is snow, the same processing as in the case of neither fog nor rain (N in step S350) is performed, and if the weather is not snow, the weather is fog or rain (step S350). The same processing as in Y) is performed.

As described above, also in this embodiment, the output unit 110 outputs a plurality of lights having different peak wavelengths, the acquisition unit 120 acquires a reflection pattern, which is the intensity waveform of the reflected light, for each of the plurality of lights, and the processing unit 130 specifies a weather-derived component contained in at least one of the plurality of reflection patterns, based on the plurality of reflection patterns. Therefore, it is possible to reduce noise caused by the weather and improve measurement accuracy.

In addition, according to the present embodiment, when the weather is not foggy or rainy, the processing unit 130 extracts peaks other than the matching peak from among the peaks extracted by the matching peak extraction unit 132 in at least one reflection pattern. identified as a component that On the other hand, when the weather is foggy or rainy, the processing unit 130 identifies, among the coincident peaks, the peak whose level increases as the wavelength of light is longer, as a component derived from the weather. Therefore, without determining the number of coincident peaks, it is possible to perform processing suitable for the weather and to identify components derived from the weather.

(Fourth embodiment)
FIG. 15 is a block diagram illustrating the configuration of the distance measuring device 10 according to the fourth embodiment, and FIG. 16 is a diagram showing the usage environment of the distance measuring device 10 according to this embodiment. The distance measuring device 10 according to this embodiment is the same as at least one of the second and third embodiments, except that the weather information acquisition unit 160 acquires weather information from another distance measuring device 10 through the communication unit 170. is.

The distance measuring device 10 according to this embodiment is connected to a server 60 via a communication network 70 and further includes a communication section 170 . The communication unit 170 determines the weather based on the information indicating the temperature and the information indicating the illuminance, and when the weather information acquisition unit 160 acquires the weather information, the communication unit 170 acquires the information together with the information indicating the position and time of the distance measuring device 10. The weather information is transmitted to the server 60.

Further, in this embodiment, the communication unit 170 transmits to the server 60 a signal requesting transmission of weather information and information indicating the position of the distance measuring device 10 . Then, when the communication unit 170 receives the weather information from the server 60 based on the request, the weather information acquisition unit 160 acquires the received weather information. Further, when the communication unit 170 fails to receive the weather information from the server 60, the weather information acquisition unit 160 acquires temperature information obtained by a sensor provided near the distance measuring device 10 and information indicating the illuminance. To obtain weather information by discriminating the weather based on the information. Further, when the communication unit 170 cannot receive the weather information from the server 60, the weather information acquisition unit 160 may access the server of the weather information providing service to acquire the weather information.

The communication unit 170 is an interface for wirelessly transmitting and receiving information via the communication network 70 . The server 60 can transmit and receive information to and from a plurality of distance measuring devices 10 via the communication network 70 . A distance measuring device 10 according to this embodiment is attached to, for example, a moving object. Further, the mobile body is provided with position recognition means such as a GPS (Global Positioning System) device capable of recognizing the position (latitude and longitude) of the mobile body. The position recognition means generates information indicating the position of the mobile object.

In this embodiment, the server 60 receives and holds the weather information, position and time information transmitted from the distance measuring device 10, and also sends effective weather information to other distance measuring devices in light of the position information and the like. 10. By sharing information in this way, each distance measuring device 10 can efficiently improve the accuracy of distance measurement.

FIG. 17 is a block diagram illustrating the functional configuration of the server 60. As shown in FIG. Specifically, the server 60 includes a communication section 610 , a selection section 620 and a storage section 630 . Communication unit 610 is an interface for transmitting and receiving information via communication network 70 . Communication unit 610 receives weather information transmitted from communication unit 170 of distance measuring device 10 . This weather information is information obtained by discriminating the weather by each distance measuring device 10 . The weather information is accompanied by information indicating the location and time when the weather information was acquired. The received weather information is stored in storage unit 630 together with information indicating the location and time.

On the other hand, when the communication unit 610 receives a request for sending weather information with location information from another distance measuring device 10, the selection unit 620 stores valid weather information in light of the location information and the time when the request was received. Select from section 630 . In selecting valid weather information, the selector 620 compares the location information associated with the weather information with the location information associated with the request to determine whether the locations indicated are sufficiently close. . For example, if the distance between two positions is equal to or less than a predetermined reference distance, it is determined that they are sufficiently close. Further, the selection unit 620 compares the information indicating the time attached to the weather information and the time when the request is received, and determines whether or not those times are sufficiently close. For example, if the difference between the two times is less than or equal to a predetermined reference time, it is determined that they are sufficiently close. Information indicating the reference distance and the reference time is stored in advance in the storage unit 630 and can be read out and used by the selection unit 620 .

The selection unit 620 performs the above determination for each of the plurality of weather information held in the storage unit 630, and selects weather information determined to be sufficiently close in both position and time. Note that when it is determined that both the positions and times of the multiple weather information are sufficiently close, the weather information with the closest position is selected. Alternatively, the weather information with the closest time may be selected.

The server 60 transmits the weather information selected by the selection unit 620 to the distance measuring device 10 that transmitted the request. The distance measuring device 10 that sent the request can receive the weather information from the server 60 and use it for noise reduction.

On the other hand, if there is no weather information determined by the selector 620 to be sufficiently close in both position and time, the server 60 cannot provide the weather information to the distance measuring device 10 that has transmitted the request. Send information to that effect. The distance measuring device 10 that cannot receive the weather information determines the weather by itself based on the information indicating the temperature and the information indicating the illuminance obtained from the sensor provided on the moving object and obtains the weather information. Further, when the communication unit 170 cannot receive the weather information from the server 60, the weather information acquisition unit 160 may access the server of the weather information providing service to acquire the weather information.

As described above, also in this embodiment, the output unit 110 outputs a plurality of lights having different peak wavelengths, the acquisition unit 120 acquires a reflection pattern, which is the intensity waveform of the reflected light, for each of the plurality of lights, and the processing unit 130 specifies a weather-derived component contained in at least one of the plurality of reflection patterns, based on the plurality of reflection patterns. Therefore, it is possible to reduce noise caused by the weather and improve measurement accuracy.

Additionally, in this embodiment, when the communication unit 170 receives weather information from the server 60, the processing unit 130 uses the weather information to reduce noise in the reflection pattern. By sharing information in this way, each distance measuring device 10 can obtain the latest weather information with pinpoint accuracy, that is, with higher positional accuracy, and can efficiently improve the accuracy of distance measurement.

Although the embodiments and examples have been described above with reference to the drawings, these are examples of the present invention, and various configurations other than those described above can be adopted.

For example, in the sequence diagrams and flowcharts used in the above description, a plurality of steps (processes) are described in order, but the execution order of the steps executed in each embodiment is not limited to the order of description. In each embodiment, the order of the illustrated steps can be changed within a range that does not interfere with the content. Moreover, each of the above-described embodiments can be combined as long as the contents do not contradict each other.

10 Distance measuring device 20 Target object 22 Particle 41 Noise peak 42 Target peak 60 Server 70 Communication network 110 Output unit 120 Acquisition unit 130 Processing unit 132 Match peak extraction unit 134 Match peak number determination unit 136 Identification unit 138 Weather determination unit 140,630 Storage unit 150 Distance calculation unit 160 Weather information acquisition unit 170, 610 Communication unit 620 Selection unit 810 Laser light source 812 Controller 814 Collimator lens 830 Half mirror 850a First light receiving element 850b Second light receiving element 851a First filter 851b Second filter 852 detection side lens 853 detection circuit 870 information processing device

Claims (7)

A device for identifying components derived from weather,
an output unit that outputs a plurality of lights with different peak wavelengths;
an acquisition unit configured to acquire a reflection pattern, which is an intensity waveform representing a relationship between the intensity of the reflected light and the time from when the light is emitted from the output unit until the reflected light is detected, for each of the plurality of lights;
a processing unit that specifies, based on the plurality of reflection patterns, the component derived from the weather contained in at least one of the plurality of reflection patterns;
with
The processing unit is
a matching peak extracting unit for extracting matching peaks having matching peak times of reflected light intensity in the plurality of reflection patterns;
a matching peak number determination unit that determines the number of matching peaks;
and an identifying unit that identifies the component derived from the weather based on the determination result of the coincident peak number determining unit. 2. The apparatus of claim 1, wherein
The matching peak extracting unit compares time points of intensity peaks of the reflected light in the plurality of reflection patterns and extracts the matching peak. 3. A device according to claim 1 or 2, wherein
The specifying unit specifies, when the number of matching peaks is 1 in the determination result of the matching peak number determining unit, peaks other than peaks having matching peak times as components derived from the weather. In the device according to any one of claims 1-3,
When the number of matching peaks is 2 or more in the determination result of the matching peak number determining unit, the specifying unit increases the peak intensity as the peak wavelength of the light among the peaks with matching peak times is longer. A device for identifying peaks as components derived from the weather. In the device according to any one of claims 1-4,
The processing unit identifies the component derived from the weather using weather information indicating the weather at the time when the plurality of reflection patterns are acquired. In the device according to any one of claims 1-5,
The matching peak number determining unit determines whether the number of matching peaks is one or two or more. A method for identifying weather-derived components, comprising:
Output multiple lights with different peak wavelengths,
For each of the plurality of lights, obtaining a reflection pattern, which is an intensity waveform indicating the relationship between the time from when the light is emitted until the reflected light is detected, and the intensity of the reflected light;
identifying the component derived from the weather contained in at least one of the plurality of reflection patterns based on the plurality of reflection patterns;
In identifying the ingredients derived from the weather,
extracting matching peaks in which the time points of the peaks of the intensity of the reflected light match in the plurality of reflection patterns;
determining the number of matching peaks;
A method for identifying the weather component based on the determination result of the number of matching peaks.

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