JP2022168956A - Laser measuring device, and measurement method thereof - Google Patents

Abstract

To provide a laser measuring device capable of suppressing degradation of accuracy in measurement results even in an environment where density of fog varies moment by moment depending on the place, and a measurement method thereof.SOLUTION: A disclosed laser measuring device 100 for measuring a distance to an object includes: a fog condition detection unit 1 that detects received light intensity by receiving reflected light from the object to be measured irradiated with a visible light laser; and a distance measurement unit 2 that measures the distance using the reflected light from the object irradiated with a near-infrared laser and finds the distance to the measured object in a range determined to be least affected by fog on the basis of, the received light intensity detected by the fog condition detection unit on the basis of, determination information in which the minimum value of received light intensity that satisfies given ranging accuracy is stored as permissible received light intensity for each distance to the measured object.SELECTED DRAWING: Figure 4

Description

The present invention relates to a TOF (Time of Flight) type laser measuring device and a measuring method for determining a distance by measuring the time from irradiating an object with a pulsed laser beam to receiving reflected light.

In harbors, rivers, forests, and indoor environments where fog occurs, laser light may be affected by fog, resulting in measurement errors. For this reason, near-infrared light, which has a longer wavelength than visible light and is highly transparent to fog, is used as the laser light for the laser measurement device.

Various techniques have been devised in order to suppress deterioration in distance measurement accuracy due to the influence of fog in laser measurement devices.
For example, by selecting the wavelength of the laser light according to the transparency of the air in the measurement environment, distance measurement can be performed even if the measurement environment is poor (even if the air transparency in the measurement environment is poor). There is a distance measuring device capable of highly accurate measurement when the environment is good (Patent Document 1). In this distance measuring device, when the transparency of the air in the measurement environment is poor, a long wavelength of 1064 nm, which is less likely to be scattered by dust or water vapor, is selected.

In addition, by making it possible to receive a plurality of reflected lights of near-infrared pulsed laser light reflected by at least one target, and by changing the setting of the threshold value of the received light intensity according to the measurement time, that is, the distance, fog and fog can be obtained. There is a laser rangefinder equipped with a circuit that identifies reflectors other than the reflector (Patent Document 2).

JP 2008-292370 A JP 2017-032547 A

In general, the particle size of water droplets in fog is about several μm to several tens of μm, which is about the same size, several times, or several tens of times larger than the wavelength of near-infrared laser light. With the distance measuring device of Document 1, it is not possible to completely prevent the deterioration of accuracy due to the influence of fog.

In addition, the laser range finder disclosed in Patent Document 2 can receive reflected light from water droplets in the fog and reflected light from an object in the back that has passed through the fog. However, even if it does pass, it deviates from the geometrical propagation path due to scattering and interference.

SUMMARY OF THE INVENTION An object of the present invention is to provide a laser measurement apparatus and a measurement method that do not lower the accuracy of measurement results even in an environment where the concentration of fog varies from place to place from moment to moment.

In order to solve the above-mentioned problems, a laser measuring device for measuring the distance to a measurement object of the present invention includes a fog state detection unit that receives reflected light from a measurement object irradiated with a visible light laser and detects the received light intensity, Distance measurement using reflected light from a measurement object irradiated with a near-infrared light laser, and determining the distance to the measurement object in a range determined to be less affected by fog based on the received light intensity detected by the fog state detection unit. I tried to prepare a part and.

Further, the measurement method of the laser measurement device of the present invention includes a fog state detection step of receiving reflected light from a measurement object irradiated with a visible light laser and detecting the light reception intensity, and in parallel with the fog state detection step, The step of measuring the distance by the light reflected from the object to be measured irradiated with a near-infrared light laser, and the effect of fog on the distance to the object measured in the step of measuring the distance, based on the received light intensity detected in the step of detecting the fog state. and a distance obtaining step of obtaining the distance to the measurement object by obtaining the distance in the range determined to be small.

According to the present invention, in an environment where the density of fog changes from place to place, the distance to the object is measured by the laser measurement device within a range where the influence of fog on the deterioration of distance measurement accuracy is small. Credibility can be maintained.

It is a figure which shows the environment where the laser measuring device of embodiment performs distance measurement. FIG. 10 is a diagram showing a time change of the received light intensity of the light beam of the near-infrared light laser reflected by the measurement target after the light beam of the near-infrared light laser is irradiated. It is a figure which shows the relationship of the light reception intensity|strength of the reflected light from a measuring object, and distance for every fog density. It is a figure explaining the database which shows the relationship between the light reception intensity|strength of reflected light, and a measurement error with respect to a distance. It is a lineblock diagram of a laser measuring device of an embodiment. 3 is a diagram showing an example of an information registration/correction screen displayed on a monitor 3 in a camera parameter storage unit; FIG. It is a figure explaining the operation|movement flow of the laser measuring device of embodiment. It is a figure explaining the other operation|movement flow of the laser measuring device of embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an environment in which the laser measurement device 100 of the embodiment performs distance measurement.
The laser measurement apparatus 100 of the embodiment irradiates a near-infrared laser light beam to measure a distance by the TOF method, and irradiates a visible light laser slit light to perform three-dimensional measurement based on a captured image. As shown in FIG. 1, the laser measurement device 100 irradiates a near-infrared laser light beam and a visible light laser slit light so as to scan an irradiation range 6, and measures the distance L to the measurement target 4. .

Fog 5 may occur in the irradiation range 6 when measuring in harbors, rivers, forests, etc., or indoors. The light beam of the near-infrared laser emitted from the laser measurement device 100 and the slit light of the visible light laser are scattered and attenuated by the fog 5. , the accuracy of the measured distance decreases.
A near-infrared light laser is less susceptible to fog than a visible light laser, but even the light beam of the near-infrared light laser cannot ignore the deterioration in accuracy due to fog.

FIG. 2 is a diagram showing the change over time of the received light intensity of the light beam of the near-infrared light laser reflected by the measurement object 4 after the light beam of the near-infrared light laser is irradiated.
In the TOF method distance measurement, the distance from the laser measurement device 100 to the measurement target 4 is obtained by converting the time from irradiation to reception of the reflected light into a distance.

FIG. 2 shows, with a solid line and a dashed line, changes over time after irradiation with a light beam of a near-infrared light laser in two states of fog 5 with different fog densities. The solid line indicates a thinner fog (lower fog density) than the dashed line.

As shown in FIG. 2, the first reflected light (fog) scattered by the fog 5 and the second reflected light from the measurement object 4 are observed. As indicated by the dashed line, when the fog is dense (fog density is high), the received light intensity of the first reflected light increases and the received light intensity of the second reflected light decreases.

When the fog is thin, the first reflected light can be removed and the distance from the second reflected light to the measurement object 4 can be obtained by setting an appropriate threshold for the received light intensity. However, when the fog is thick, the received light intensity of the first reflected light and the second reflected light are approximately the same, so the first reflected light cannot be removed.
If the fog becomes thicker, the second reflected light from the measurement object 4 cannot be received, and the distance cannot be determined.

Also, in FIG. 2, the second reflected light is indicated by a rectangle, but as the fog thickens, the reflected light scatters and the received light intensity distribution becomes smoother. Therefore, the center value of the second reflected light indicated by the dashed-dotted vertical line shifts, resulting in a shift in the detection time of the second reflected light, resulting in an error ΔL from the distance L (true value) indicated by the dashed vertical line. That is, the thicker the fog, the larger the error ΔL of the measured distance.

The laser measurement device 100 of the embodiment grasps the distance error due to fog in advance, and enables to specify the measurement range that can be measured with a predetermined distance measurement accuracy, thereby improving the reliability of the distance measurement.

Specifically, the laser measurement device 100 is configured in advance according to the typical shape (prism, cylinder, flat plate, etc.), material (iron, aluminum, concrete, etc.) and surface condition (coating, presence or absence of rust, etc.) of the object 4 to be measured. Then, the relationship between the received light intensity of the reflected light from the measurement object 4, the distance, and the measurement error is obtained for each fog density, and stored as a database (hereinafter, sometimes referred to as determination information).

The laser measuring device 100 measures the received light intensity and the distance of the reflected light from the measurement object 4 by irradiating a light beam of a near-infrared laser and measuring the distance using the laser light, which is different from the distance measurement of the TOF method. Then, referring to the database, from the relationship between the received light intensity of the reflected light corresponding to the measured distance and the measurement error, the received light intensity of the reflected light required to obtain the distance measurement accuracy is obtained, and the measured object 4 It is determined whether or not the received light intensity of the reflected light from is satisfied. If the measured received light intensity of the reflected light from the measurement object 4 is equal to or higher than the received light intensity obtained by referring to the database, the TOF method distance measurement by irradiating the light beam of the near-infrared light laser is performed at a predetermined level. Suppose that the distance measurement accuracy is satisfied.

The laser measuring device 100 of the embodiment measures the received light intensity and the distance of the reflected light from the measurement object 4 by slit light of a visible light laser that is highly sensitive to fog density, and determines the distance measurement accuracy.

FIG. 3A is a diagram showing the relationship between the received light intensity of the reflected light from the measuring object 4 and the distance for each fog density. FIG. 3A shows the relationship between the distance to the measurement object and the received intensity of the reflected light measured at fog densities A, B, and C (fog densities A<B<C).

As shown in FIG. 3A, the received light intensity of the reflected light from the measurement object 4 decreases as the distance increases (the measurement distance increases). Further, the received light intensity of the reflected light from the measuring object 4 decreases as the fog density increases.
Furthermore, due to the scattering of laser light by fog, the measurement error increases (distance measurement accuracy decreases) as the fog density increases (deepens).

For example, if the reflection intensity is nQ (intersection point Q) when the distance nL is measured with the fog density B and the reflection intensity is nP (intersection point P) when the distance L is measured with the fog density C, the distance measurement accuracy of the measurement result is is better at the intersection point Q. Therefore, in order to perform measurement that satisfies the accuracy corresponding to the measurement error in the fog density C, it is sufficient that the received light intensity of the reflected light when measuring the distance nL is nP or more.

The laser measurement device 100 of the embodiment obtains in advance the relationship between the received light intensity and the distance of the reflected light from the measurement object 4 for each fog concentration shown in FIG. It is held as a database (determination information) that indicates the relationship.

Specifically, when the laser measurement device 100 measures the distance 3L to the measurement object 4 by the slit light of the visible light laser, it refers to the database (determination information) in FIG. (Refer to the dotted line arrow in the figure) for achieving a measurement error of 3C.DELTA. corresponding to the measurement accuracy of .DELTA. Then, the received light intensity 3P of the reflected light at which the distance 3L is measured at the fog density C is extracted (see the dashed-dotted line arrow in the figure). If the received light intensity of the reflected light when measuring the distance 3L to the measurement object 4 by the slit light of the visible light laser is greater than the received light intensity 3P, the measurement error becomes smaller than 3CΔ, and the target measurement accuracy is satisfied (measurement accuracy is high).

The database (judgment information) can be obtained for each distance to the measurement target as the minimum value of the received light intensity that satisfies the predetermined distance measurement accuracy, and is stored as a function (formula) of the received light intensity, distance, and measurement error. You may

Next, the configuration of the laser measurement device 100 according to the embodiment will be described with reference to FIG.
The laser measurement device 100 includes a fog state detection unit 1 that receives reflected light from a measurement object 4 irradiated with a visible light laser and detects the intensity of received light, and a reflected light from the measurement object 4 irradiated with a near-infrared light laser. and a distance measuring unit 2 for measuring the distance to the measurement object 4 in a range determined to be less affected by fog based on the received light intensity acquired by the fog state detecting unit 1.

The fog state detection unit 1 includes a line laser 11, a camera 12, a camera/laser control unit 13, a camera parameter storage unit 14, and an image recording unit 15. Configure a device that measures by the cutting method.

Specifically, the line laser 11 irradiates the object 4 to be measured with slit light of a visible light laser.
The camera 12 captures an image of the measuring object 4 irradiated with the slit light of the visible light laser.
The camera/laser control unit 13 controls the irradiation timing and irradiation direction of the slit light of the line laser 11 to scan the measurement object 4 with the slit light, and operates the camera 12 so as to capture an image in synchronization with the irradiation of the slit light. Control.
The image recording unit 15 stores the captured image of the measurement object 4 captured by the camera 12 and irradiated with the slit light of the visible light laser.

The fog state detection unit 1 further includes a laser bright line extraction unit 16 , a camera parameter storage unit 14 and a reflected light analysis unit 17 .
The laser bright line extraction unit 16 sequentially acquires the captured images of the measurement object 4 from the image recording unit 15, extracts the laser bright lines, which are the images of the surface of the measurement object 4 illuminated by the slit light, from the captured images, and extracts the pixel positions of the laser bright lines. and the received light intensity of the reflected light of the slit light.

Specifically, the laser bright line extraction unit 16 first performs distortion correction processing on the captured image acquired from the image recording unit 15 using the camera parameters ( FIG. 5 ) in the camera parameter storage unit 14 . Next, binarization processing is performed according to the threshold value (laser light intensity value) of the received light intensity of the reflected light of the visible light laser set in the measurement parameters (FIG. 5) of the camera parameter storage unit 14 . Then, image processing for line extraction is performed to extract laser emission lines.

If the reflectance of the visible light laser differs depending on the type of the measurement target 4, the camera parameters may be provided with a threshold value for the received light intensity of the reflected light according to the measurement target. Also, the setting of the threshold value of the received light intensity of the reflected light may be changed according to the wavelength range of the visible light laser as the camera parameter.

The reflected light analysis unit 17 calculates the three-dimensional position of the laser bright line by the light section method from the pixel position of the laser bright line obtained by the laser bright line extracting unit 16 and the camera parameters described later, and measures the measurement object irradiated with the slit light. 4 shapes are obtained.
The reflected light analysis unit 17 temporarily stores the obtained reflection position of the laser bright line (irradiation position of the slit light) and the received light intensity of the reflected light together with the measurement time in a storage unit (not shown).

The fog state detection unit 1 is a device that measures the three-dimensional shape of the measurement object 4 with the camera 12 as a base point, similarly to a known distance measurement device, and the description of the measurement operation is omitted here.

The distance measurement unit 2 includes a laser light emission unit 21, a laser light reception unit 22, a distance measurement control unit 23, and a measurement data storage unit 24, and measures a distance by a TOF method by irradiating a light beam of a near-infrared laser. Construct a distance measuring device.

The laser light emitting unit 21 is a laser light emitting element such as a semiconductor laser diode that emits near-infrared laser beam light.
The laser light receiving unit 22 is a laser light receiving element that receives the reflected light of the near-infrared laser emitted from the laser light emitting unit 21 and reflected by the measurement object 4 . An avalanche photodiode or the like is used as the laser light receiving element.

The distance measurement control unit 23 controls the scanning mechanism so that the laser light emitting unit 21 and the laser light receiving unit 22 are oriented in a predetermined direction, and the near infrared light is detected from the light emission timing of the laser light emitting unit 21 and the light receiving timing of the laser light receiving unit 22. The time (flight time) from when the light laser is emitted until it is reflected by the measurement object 4 and returns is measured, and the distance to the irradiation position (reflection position) of the measurement object 4 is obtained. The reflection position of the object 4 to be measured is calculated from the distance obtained from the direction of irradiation and the time of flight, with the positions of the laser emitting section 21 and the laser receiving section 22 as base points.
In addition, the ranging control unit 23 acquires the received light intensity of the near-infrared laser reflected by the measurement object 4 .

The measurement data storage unit 24 stores the distance to the reflection position of the measurement object 4 and the received light intensity obtained by the distance measurement control unit 23 together with the measurement time for each reflection position corresponding to the irradiation direction of the near-infrared light laser. .

The determination information storage unit 26 stores a database (determination information) indicating the relationship between the received light intensity of the reflected light and the distance and the measurement error described with reference to FIG. 3B.

The fog effect determination unit 25 refers to the determination information in the determination information storage unit 26, and determines if the reflected intensity of the visible light laser at the reflection position analyzed by the reflected light analysis unit 17 is equal to or higher than the reflection intensity that satisfies a predetermined distance measurement accuracy. Determine if there is If the reflection intensity is greater than or equal to a predetermined distance measurement accuracy, it is determined that the effect of fog is small and the distance measurement accuracy is satisfied. The distance is acquired from the measurement data storage unit 24 . Note that the distance measurement accuracy is set in the camera parameter storage unit 14, which will be described later.

The distance data storage unit 27 stores the distance measured by the near-infrared laser to the reflection position of the measurement object 4 having the predetermined distance measurement accuracy determined by the fog influence determination unit 25, together with the measurement time.
In addition, the distance data storage unit 27 stores the distance measured by the near-infrared light laser to the reflection position of the measurement target 4 and the determination result of the distance measurement accuracy in the fog effect determination unit 25 in association with the reflection position of the measurement object 4 . You may do so.

The monitor 3 is a terminal unit having a display unit and an operation input unit. An operator of the laser measurement device 100 can perform operation instructions of the device and register/modify information such as various parameters in the camera parameter storage unit 14, which will be described later.

The camera parameter storage unit 14 stores the camera parameters for correction processing in the laser bright line extraction unit 16, the measurement parameters of the distance measurement unit 2 for obtaining the distance by irradiating the near-infrared laser, and the laser scanner of the distance measurement unit 2. Parameters and sensor geometric arrangement conditions of the distance measuring unit 2 (the laser emitting unit 21 and the laser receiving unit 22), the camera 12, and the line laser 11 are stored.

FIG. 5 is a diagram showing an example of an information registration/correction screen of the camera parameter storage unit 14 displayed on the monitor 3. As shown in FIG.
As the camera parameters of the camera 12, the size of the imaging device, the number of horizontal and vertical pixels of the imaging device, and the setting information of the focal length are displayed so that they can be registered and corrected.

As measurement parameters of the distance measurement unit 2, the measurement distance measurement accuracy referred to as the target distance measurement accuracy in the fog effect determination unit 25, and the characteristic information such as the typical shape, material, surface state, etc. of the object to be measured. The object, the threshold value (laser light intensity value) of the received light intensity of the reflected light of the visible light laser for extracting the laser bright line referred to by the laser bright line extracting unit 16, the fog state detecting unit 1, and the distance measuring unit 2 The setting information of the distance measurement range, which is the position information of the object 4 to be measured, is displayed so that it can be registered and corrected.

Then, as the laser scanner parameters of the distance measurement unit 2, the number of times of scanning, the number of times of data averaging when measuring the distance, and the threshold value when evaluating the distance measurement accuracy of the average value of the measured distances by the data standard deviation are registered.・Display it so that it can be corrected. How to use these setting information will be described later.

In addition, the monitor 3 displays a "sensor geometric arrangement condition" instruction button for instructing transition to a screen for registering/correcting the sensor geometric arrangement condition stored in the camera parameter storage unit 14. FIG. More specifically, on the sensor geometrical arrangement condition screen, the installation positions of the laser light emitting unit 21 and the laser light receiving unit 22 (base point for distance measurement by the light beam of the near-infrared laser) and the installation position of the camera 12 (visible light The reference point for distance measurement by laser slit light) is registered and corrected.

With the above configuration, the fog state detection unit 1 and the distance measurement unit 2 of the laser measurement device 100 measure the distance in parallel and synchronously within the predetermined distance measurement range of the measurement object 4 . Then, both the time information indicating the measurement time and the measured value are recorded. The fog effect determination unit 25 determines that the measurement time of the distance measurement unit 2 is within a predetermined time with respect to the measurement time of the fog state detection unit 1 when determining that the fog effect is small and the distance measurement accuracy is satisfied. Obtain the result of the measured distance.

When the operation time of the distance measurement of the distance measurement unit 2 is earlier than the operation time of the distance measurement of the fog state detection unit 1, the distance measurement unit 2 averages a plurality of measurements to obtain the measured distance of the reflection position, You may make it correspond with the measurement result of the fog state detection part 1. FIG.

Specifically, the laser measurement device 100 of the embodiment includes a semiconductor element such as a semiconductor laser or a photodiode, a camera, a scanning mechanism, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), HDD (Hard Disk Drive), storage devices such as flash memory, and an input/output interface. The functional units of the unit 17, the distance measurement control unit 23, and the fog effect determination unit 25 are realized by the CPU executing a program stored in the storage device.

Next, the operation flow of the laser measurement device 100 according to the embodiment will be described with reference to FIG.

In step S61, the camera parameter storage unit 14 stores the camera parameters, the measurement parameters of the distance measurement unit 2, the laser scanner parameters of the distance measurement unit 2, and the distance measurement unit 2 (the laser light emission unit 21 and the laser light reception unit) necessary for the measurement process. 22), the camera 12 and the line laser 11 are set as measurement conditions for the sensor geometric arrangement conditions.

In step S62, the fog state detection unit 1 irradiates the measurement object 4 with slit light of a visible light laser and performs scanning while performing camera imaging. A laser light beam is scanned, the distance is measured and recorded by the TOF method, and processing of camera imaging and near-infrared laser scanning is performed.

In step S63, the fog state detection unit 1 performs laser bright line extraction processing for extracting laser bright lines from the captured image of the measurement target 4 captured by the camera in step S62.

In step S64, the fog state detection unit 1 calculates the three-dimensional position of the laser emission line by the light section method from the pixel position of the laser emission line extracted in step S63 and the camera parameters. is calculated. At this time, the received light intensity of the reflected light of the visible light laser is associated with the direction (reflection position) of the laser emission line.

In step S65, the distance measurement unit 2 acquires the distance measured in S62 corresponding to the direction (reflection position) of the laser emission line calculated in step S64, and obtains the distance and direction (reflection position) of the laser emission line. A process of extracting the distance measured by the near-infrared laser is performed.
When the same measurement object 4 is continuously measured, the moving average of the distances measured in S62 may be calculated as the distance measured by the near-infrared laser.

In step S66, the distance measurement unit 2 measures the distance including the desired measurement error by referring to a database (determination information) indicating the relationship between the distance and the received light intensity of the reflected light of the visible light laser set in advance and the measurement error. The received light intensity of the reflected light required to obtain the distance extracted in step S65 is obtained. Determine whether the intensity is equal to or higher than the intensity. If the received intensity of the reflected light is greater than or equal to the required intensity, the distance measurement unit 2 determines that the distance extracted in step S65 is less affected by fog and satisfies the accuracy of distance measurement. Determine impact.

In step S67, the distance measurement unit 2 stores the distance and the measurement time determined in step S67 as a state in which the influence of fog is small and satisfies the distance measurement accuracy as distance data, and performs distance data storage processing.
In step S67, the distance measurement unit 2 may store the distance extracted in step S65, the measurement time, and the determination result of step S66.

In step S68, the laser measurement device 100 returns to step S62 if the measurement is to be continued (No in S68), and ends the processing if the measurement is finished (Yes in S68).

The flowchart of FIG. 6 shows that when the fog state detection unit 1 and the distance measurement unit 2 measure the distance in parallel and in synchronization with each other in the predetermined distance measurement range of the measurement object 4, each of the predetermined distance measurement ranges This shows the processing for the case where the measurement of is performed once. FIG. 7 illustrates a case where the distance measurement unit 2 averages a plurality of measurements to obtain the measured distance of the reflection position, and associates the result with the measurement result of the fog state detection unit 1 .

Steps S61 to S68 in the flow chart of FIG. 7 are the same as those in FIG. 6, so description thereof will be omitted here.
In step S71, the distance measurement unit 2 calculates the average value of the distances measured by the plurality of near-infrared light lasers extracted in step S65, and performs the process of averaging the distance data.

In step S72, the distance measurement unit 2 calculates the standard deviation of the distance data, and performs a process of confirming whether it is equal to or less than the distance measurement accuracy. Specifically, the standard deviation of the distances measured by the plurality of near-infrared light lasers extracted in step S65 is calculated, and it is determined whether the calculated standard deviation is equal to or less than the distance measurement accuracy. If the calculated standard deviation is less than the distance measurement accuracy, the average value of the distances calculated in step S71 is used as the distance data to be stored in step S67.
By adding the averaging process in this way, it is possible to further suppress the deterioration of the ranging accuracy due to the influence of fog.

In the above, we explained the process of using the average value of the distances measured by multiple near-infrared lasers determined to be less affected by fog as the distance data. Near-infrared light determined to be less affected by fog when the difference between the measured distance and the distance obtained from the laser emission line of the visible light laser at the same reflection position calculated in step S64 is less than or equal to the distance measurement accuracy. The distance measured by the laser may be used as the distance data stored in step S67.

In this case, the average value of the distances measured by a plurality of near-infrared light lasers determined to be less affected by fog, and the distance obtained from the laser emission line of the visible light laser at the same reflection position calculated in step S64. If the difference is equal to or less than the distance measurement accuracy, the distance measured by the near-infrared laser determined to be less affected by fog may be used as the distance data to be stored in step S67.

Furthermore, we calculated the average value of the distances measured with multiple near-infrared lasers that were judged to have little effect from fog, and the average value of the distances obtained from the laser emission line of the visible light laser at the same reflection position, and calculated the two averages. If the difference in values is equal to or less than the distance measurement accuracy, the average value of the distances measured by the near-infrared light laser determined to be less affected by fog may be used as the distance data to be stored in step S67.

In the laser measurement device 100 of the above embodiment, the case where the fog state detection unit 1 and the distance measurement unit 2 operate in parallel and synchronously over the predetermined distance measurement range of the measurement object 4 has been described. After 1 measures the measurement object 4, based on the measurement result of the fog state detection unit 1, the distance measurement unit 2 determines that the range is less affected by fog and satisfies the distance measurement accuracy. may be emitted to measure the distance.

Further, in the laser measurement device 100 of the embodiment, a configuration will be described in which the fog state detection unit 1 irradiates the measurement object 4 with slit light of a visible light laser, receives reflected light from the measurement object 4, and acquires the received light intensity. However, without being limited to this configuration, the fog state detection unit 1 may detect the state of fog between the laser measuring device 100 and the measurement object 4 by another method.

For example, distance measurement is performed using a millimeter-wave radar in a foggy environment, and the relationship between the received intensity of the reflected wave, the distance, and the measurement error is obtained in advance. (determination information storage unit 26). Then, the fog state detection unit 1 irradiates the measurement target 4 with the millimeter wave radar, receives the reflected wave from the measurement target 4 to obtain the reception intensity, and the fog effect determination unit 25 detects the reflected wave of the millimeter wave radar. It is configured to determine the influence of fog based on the received intensity of the

The technique of the laser measurement device 100 of the embodiment can be applied to a TOF type shape measurement device that obtains a three-dimensional shape by measuring the time from when the object is irradiated with the pulsed laser beam to when the reflected light is received. Needless to say.

The present invention is not limited to the above-described embodiments, and includes various modifications. The above embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the described configurations. Also, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.

Reference Signs List 1 fog state detection unit 2 distance measurement unit 3 monitor 4 measurement object 11 line laser 12 camera 13 camera/laser control unit 14 camera parameter storage unit 15 image recording unit 16 laser emission line extraction unit 17 reflected light analysis unit 21 laser emission unit 22 laser Light receiving unit 23 Ranging control unit 24 Measurement data storage unit 25 Fog effect determination unit 26 Determination information storage unit 27 Distance data storage unit 100 Laser measurement device

Claims (12)

A laser measuring device for measuring the distance to a measurement object,
a fog state detection unit that receives reflected light from a measurement target irradiated with a visible light laser and detects the received light intensity;
Distance measurement using reflected light from a measurement object irradiated with a near-infrared light laser, and determining the distance to the measurement object in a range determined to be less affected by fog based on the received light intensity detected by the fog state detection unit. Department and
A laser measurement device comprising: In the laser measurement device according to claim 1,
The distance measurement unit irradiates a near-infrared light laser to measure the distance a plurality of times, calculates the average value of the measured distances, and calculates the average value when the standard deviation of the average value is equal to or less than a predetermined distance measurement accuracy. A laser measuring device characterized in that a value is set as a distance to an object to be measured. In the laser measurement device according to claim 1,
The fog state detection unit is
A line laser that irradiates a slit light of a visible light laser to the measurement object,
a laser bright line extraction unit that extracts bright line information of the slit light from the captured image of the measurement target;
a reflected light analysis unit that obtains, from the bright line information, the reflection position of the slit light on the measurement target and the received light intensity of the reflected light of the slit light for each of the reflection positions,
The distance measurement unit
a fog effect determination unit that determines, based on the received light intensity, the effect of fog when irradiating a near-infrared light laser onto a reflection position of a visible light laser on a measurement object and performing distance measurement for each of the reflection positions;
A laser measurement device comprising: In the laser measurement device according to claim 3,
The distance measurement unit
The received light intensity of the reflected light of the visible light laser and the distance measurement accuracy of the near-infrared light laser for a plurality of distances to the measurement object are measured in advance by changing the density of the fog, and the predetermined distance measurement accuracy is satisfied. A determination information storage unit that stores the minimum value of the received light intensity as an allowable received light intensity for each distance to the measurement object,
The fog effect determination unit
When the received light intensity of the reflected light determined by the reflected light analysis unit is greater than the allowable received light intensity by referring to the determination information storage unit, the effect of fog on distance measurement by irradiating the measurement target with a near-infrared light laser. determined to be less,
The laser measuring device, wherein the distance measuring unit uses the reflection position of the visible light laser determined by the fog influence determining unit to be less affected by fog as a range for obtaining the distance of the object to be measured. The laser measurement device according to claim 4, further comprising:
The distance measurement unit calculates the distance to the measurement object calculated from the reflection position of the visible light laser on the measurement object and the distance measured by irradiating the reflection position of the visible light laser on the measurement object with a near-infrared light laser. 1. A laser measuring device, wherein a distance measured by irradiating a near-infrared light laser is used as a distance to an object to be measured when the difference is equal to or less than a predetermined distance measuring accuracy. The laser measurement device according to claim 4, further comprising:
The fog state detection unit is
The distance to the measurement object calculated from the reflected position of the visible light laser on the measurement object is obtained a plurality of times, and the average value is calculated to obtain the distance to the measurement object by the visible light laser,
The distance measurement unit
The distance measured by irradiating the reflection position of the visible light laser on the measurement object with the near-infrared laser is obtained a plurality of times, and the average value is calculated to obtain the distance to the measurement object by the near-infrared laser,
When the difference between the distance to the measurement object by the visible light laser and the distance to the measurement object by the near-infrared light laser is equal to or less than a predetermined distance measurement accuracy, the measurement object by the near-infrared light laser A laser measuring device characterized in that the distance to is set as the distance to the object to be measured. The laser measurement device according to claim 4, further comprising:
The distance measurement unit irradiates a near-infrared light laser to measure the distance a plurality of times, calculates the average value of the measured distances, and calculates the average value when the standard deviation of the average value is equal to or less than a predetermined distance measurement accuracy. A laser measuring device characterized in that a value is set as a distance to an object to be measured. A measuring method for a laser measuring device,
a fog state detection step of receiving reflected light from a measurement object irradiated with a visible light laser and detecting the received light intensity;
In parallel with the fog state detection step, a step of measuring a distance by reflected light from a measurement target irradiated with a near-infrared light laser;
a distance acquisition step of acquiring the distance to the measurement object by obtaining the distance to the measurement object measured in the step of measuring the distance in a range determined to be less affected by fog based on the received light intensity detected in the fog state detection step; ,
A measuring method comprising: In the measuring method according to claim 8,
The fog state detection step includes:
A slit light of a visible light laser is irradiated from a line laser to the measurement object,
Extracting bright line information of the slit light from the captured image of the measurement object irradiated with the slit light,
Obtaining the reflection position of the slit light on the measurement target from the bright line information and the received light intensity of the reflected light of the slit light for each of the reflection positions,
The distance acquisition step includes:
The received light intensity of the reflected light of the visible light laser and the distance measurement accuracy of the distance measurement by the near-infrared light laser for a plurality of distances to the measurement object are measured in advance by changing the density of the fog, and the predetermined distance measurement accuracy is satisfied. With reference to determination information stored for each distance to the measurement target, the minimum value of the received light intensity being the allowable received light intensity, it is determined that the influence of fog is small based on the received light intensity acquired in the fog state detection step. measurement method. In the measuring method according to claim 9,
The distance acquisition step further includes:
The difference between the distance to the measurement object calculated from the reflection position of the visible light laser on the measurement object and the distance measured by irradiating the reflection position of the visible light laser on the measurement object with a near-infrared laser is a predetermined measurement. A measuring method, comprising: setting a distance measured by irradiating a near-infrared light laser as a distance to a measurement target when the distance accuracy is equal to or less than the distance accuracy. In the measuring method according to claim 9,
The distance acquisition step further includes:
The distance to the measurement object calculated from the reflected position of the visible light laser on the measurement object is obtained a plurality of times, and the average value is calculated to obtain the distance to the measurement object by the visible light laser,
The distance measured by irradiating the reflection position of the visible light laser on the measurement object with the near-infrared laser is obtained a plurality of times, and the average value is calculated to obtain the distance to the measurement object by the near-infrared laser,
When the difference between the distance to the measurement object by the visible light laser and the distance to the measurement object by the near-infrared light laser is equal to or less than a predetermined distance measurement accuracy, the measurement object by the near-infrared light laser A measuring method, characterized in that the distance to is taken as the distance to the object to be measured. In the measuring method according to claim 9,
The distance acquisition step further includes:
Measure the distance multiple times by irradiating a near-infrared laser, calculate the average value of the measured distances, and calculate the average value when the standard deviation of the average value is less than a predetermined distance measurement accuracy. A measuring method characterized by measuring a distance.

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