JP7173872B2 - Ranging device and ranging method - Google Patents

Description

The present invention relates to a rangefinder and a rangefinder method.

2. Description of the Related Art In a garbage incineration facility, deposits (for example, clinker) formed by accumulated dust and the like generated by garbage incineration adhere to the refuse incinerator and the pipes communicating therewith, and the deposits grow gradually. When deposits grow in a garbage incinerator, the deposits obstruct gas convection in the furnace, resulting in poor incineration. As deposits grow in the pipes, the flow of gas through the pipes is impeded and, at worst, the pipes become clogged. For this reason, it is necessary to monitor the thickness of deposits attached to garbage incinerators and pipes.

For example, Patent Literature 1 discloses a technique for monitoring the thickness of sediments deposited in a high-temperature furnace (for example, a garbage incinerator) by distance measurement using a stereo camera. For example, Patent Literature 2 discloses a technique for monitoring the thickness of deposits deposited on a pipe connected to a refuse incinerator by distance measurement using laser light.

Distance measurement using a stereo camera measures the distance to a distance measurement target using the principle of triangulation based on images of the distance measurement target captured by cameras installed at multiple locations.

Distance measurement using a laser beam irradiates an object for distance measurement with a laser beam, and measures the distance to the object for distance measurement based on reflected light reflected from the object for distance measurement. Distance measurement methods using laser light include a triangulation distance measurement method, a phase difference detection method, and a TOF (Time of Flight) method. Since an LED can be used as a light source in place of a laser device, distance measurement using a light beam is described instead of distance measurement using a laser beam.

JP 2014-85069 A JP 2017-219440 A

Ranging using a stereo camera and ranging using a light beam each have advantages and disadvantages. The inventors have studied a distance measurement technique that can use these distance measurements differently depending on the environment in which the distance measurement target is placed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a distance measuring apparatus and a distance measuring method capable of selectively using distance measurement using a stereo camera and distance measurement using a light beam according to the environment in which the distance measurement target is placed. is.

A distance measuring device according to a first aspect of the present invention comprises a stereo camera, a light emitting unit, and a first method for measuring a distance to a distance measuring object based on an image of the distance measuring object photographed by the stereo camera. A second range finding method in which the light emitting unit irradiates the target with a light beam and measures the distance to the target based on the reflected light. and a judgment unit for judging whether or not the first distance measurement can be performed based on dust present in a space up to the distance measurement object, wherein the distance measurement unit When it is determined that the first distance measurement cannot be performed, the second distance measurement is performed, and when it is determined that the first distance measurement can be performed, the first distance measurement is performed.

The inventor paid attention to the dust existing in the space up to the distance measurement object. The first ranging (ranging using a stereo camera) has the advantage of a wide ranging range, but has the disadvantage of being easily affected by dust floating in the space up to the ranging target (the concentration of dust is high). distance measurement becomes impossible). The second ranging (ranging using a light beam) has the advantage of being less susceptible to dust floating in the space up to the ranged object (ranging is possible even if the concentration of dust is high). , has the disadvantage of a narrow ranging range.

The distance measuring device according to the first aspect of the present invention performs the second distance measurement and performs the first distance measurement when it is determined that the first distance measurement cannot be performed due to dust floating in the space up to the distance measurement target. When it is determined that the distance can be obtained, the first distance measurement is performed. Therefore, according to the distance measuring device according to the first aspect of the present invention, distance measurement using a stereo camera and distance measurement using a light beam can be selectively used according to the environment in which the distance measurement object is placed. .

In the above configuration, the determination unit compares the index value indicating the concentration of the dust with a predetermined threshold value, and when the index value exceeds the threshold value, the first distance measurement is performed. determining that the first distance measurement can be performed when the index value is equal to or less than the threshold value, and the index value is determined to be the measurement reflected in the image detected by edge detection for the image; It is based on the number of pixels that make up the edge of the distance object.

When the concentration of dust floating in the space up to the distance measurement object is low, the uneven shape of the distance measurement object is reflected in the image captured by the stereo camera, and the distance measurement object having the uneven shape is captured. On the other hand, when the density of dust floating in the space up to the distance measurement object is high, the image captured by the stereo camera does not reflect the uneven shape of the distance measurement object and shows a flat distance measurement object.

The inventors of the present invention found that the number of pixels constituting the edge of the object for distance measurement in the image detected by edge detection for the image of the object for distance measurement photographed by a stereo camera and the density of dust have a positive correlation. found to have Therefore, an index value indicating the density of dust can be determined based on the number of pixels. The determination unit uses this index value to determine whether or not the first distance measurement can be performed.

In the above configuration, let n1 be the number of pixels forming the edge of the object for distance measurement detected by the edge detection, and n2 be the number of pixels forming the area of the area in which the object for distance measurement appears in the image. and n3 is the number of pixels forming the edge detected by the edge detection, and n4 is the number of pixels forming the edge indicating the shape of the area detected by the edge detection, the index value is It is shown by the following formula.
n1=n3-n4
Index value = n1/n2

This configuration shows an example of an index value. Note that n1 itself may be used as an index value. Here, n1/n2 is used as an index value, considering that the measurement area of the area where the range-finding object occurs changes due to factors such as the lens being contaminated with dust and the field of view of the stereo camera narrowing. .

In the above configuration, the distance measuring device is arranged outside the product, which is at least one of the waste incinerator and the pipe connected to the waste incinerator, and is provided in the product through a through hole leading to the inside of the product. to measure the distance to the range-finding object generated inside.

Deposits to be distance-measured accumulate inside the product (inside the garbage incinerator, inside the piping), so it is necessary to monitor the thickness of the deposits using a distance measuring device. When the distance measuring device is arranged inside the product, it is also necessary to arrange facilities for cooling the distance measuring device (cooling pipes, etc.) inside the product. In this case, since the distance measuring device and the equipment for cooling it are arranged inside the product, maintenance of these devices requires time and effort. According to this configuration, the distance measuring device and the equipment for cooling it are arranged outside the product, so that maintenance thereof is not troublesome.

When the distance measuring device is arranged inside the product, the view of the stereo camera may be obstructed by the distance measuring object adhering to the distance measuring device. With this configuration, the distance measuring device is arranged outside the product, so this does not occur.

In the above configuration, the distance between the one camera and the other camera that constitute the stereo camera is the distance that allows the one camera and the other camera to photograph the range-finding target through the through hole. is the maximum value of

The accuracy of the first ranging improves as the distance between one camera and the other camera increases. The range finder is arranged outside the product, and these cameras photograph the target for range measurement inside the product through the through hole. Therefore, in order to secure the field of view of each of these cameras, the interval between these cameras is subject to the restriction of the diameter of the through hole and has an upper limit (maximum value). According to this configuration, the accuracy of the first distance measurement is improved as much as possible by setting the interval to the maximum value.

In the above configuration, the light-emitting unit irradiates the range-finding object with the light beam having a wavelength included in a wavelength band shorter than the wavelength band of red, and the range-finding device provides a distance between the stereo camera and the through-hole. An optical filter that is disposed between and has transparency to the wavelength of the light beam and cuts the red wavelength band or higher, wherein the distance measuring unit is one of the cameras that constitute the stereo camera The second distance measurement for measuring the distance to the object for distance measurement is performed by triangulation based on the image of the reflected light photographed using the .

Since the inside of the product is at a high temperature, the light detected from the inside has a high intensity in the wavelength band above the red wavelength band. Therefore, the intensity of noise increases in the wavelength band equal to or higher than the red wavelength band. In this configuration, an optical filter (for example, a bandpass filter) cuts off the red wavelength band and above. Therefore, the SN ratio of the image of the target for distance measurement captured by the stereo camera and the image of the reflected light captured by one of the cameras constituting the stereo camera can be improved.

A distance measurement method according to a second aspect of the present invention includes first distance measurement for measuring a distance to a distance measurement target based on an image of the distance measurement target taken by a stereo camera, and A distance measurement method for selectively executing a second distance measurement in which a distance target is irradiated with a light beam and the distance to the distance measurement object is measured based on the reflected light. a determination step of determining whether or not the first distance measurement can be performed due to dust existing in the space up to the distance measurement object; and when it is determined that the first distance measurement cannot be performed, the second a distance measurement step of executing distance measurement, and executing the first distance measurement when it is determined that the first distance measurement can be performed, wherein the determination step includes an index value indicating the density of the dust. is compared with a predetermined threshold value, and when the index value exceeds the threshold value, it is determined that the first distance measurement cannot be performed, and when the index value is equal to or less than the threshold value, It is determined that the first distance measurement can be performed, and the index value is based on the number of pixels constituting the edge of the distance measurement target in the image, detected by edge detection on the image .

The distance measuring method according to the second aspect of the present invention defines the distance measuring apparatus according to the first aspect of the present invention from the viewpoint of the method, and has the same effects as the distance measuring apparatus according to the first aspect of the present invention. have

According to the present invention, distance measurement using a stereo camera and distance measurement using a light beam can be selectively used according to the environment in which the distance measurement target is placed.

1 is a block diagram showing the configuration of a distance measuring device according to an embodiment; FIG. It is a schematic diagram which shows a part of gasification melting furnace. It is a schematic diagram which shows the relationship between the distance measuring device shown in FIG. 1, and the piping in which this ranging device is arrange|positioned. It is the top view which looked at the port from upper direction. Fig. 3 is a graph showing spectra measured inside a pipe during combustion inside a melting furnace; FIG. 4 is an image diagram showing an image of the inside of a pipe captured by a stereo camera in a state where the concentration of dust floating inside the pipe is low. FIG. 4 is an image diagram showing an image of the inside of a pipe taken by one camera of the stereo camera in a state where the concentration of dust floating inside the pipe is high. 4 is a flow chart for explaining a process of calculating an index value; FIG. 4 is an image diagram showing an example of a binarized image; FIG. 10 is an image diagram showing an example of an image subjected to edge detection processing; FIG. 4 is an image diagram showing an example of an image showing edges of deposits; 4 is a flowchart for explaining the operation of the distance measuring device according to the embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In each figure, the configurations denoted by the same reference numerals indicate the same configuration, and the description of the content of the configuration that has already been described will be omitted. In this specification, reference numerals without hyphens are used when referring to generically (for example, camera 20), and reference numerals with hyphens are used when referring to individual components (for example, camera 20-1, camera 20-2).

FIG. 1 is a block diagram showing the configuration of a distance measuring device 100 according to an embodiment. FIG. 2 is a schematic diagram showing a part of the gasification melting furnace 200. As shown in FIG. FIG. 3 is a schematic diagram showing the relationship between the distance measuring device 100 and the pipe 203 in which the distance measuring device 100 is arranged. Referring to FIG. 2, gasification melting furnace 200 includes melting furnace 201, boiler 202, and piping 203 connecting these. The melting furnace 201 is supplied with combustible gas and char (coal-like unprocessed matter) generated by thermal decomposition of waste. In the melting furnace 201 these are burned. Slag produced by combustion is discharged from the slag outlet 204 . Heat generated by combustion is recovered by boiler 202 to generate steam.

A deposit 300 , which is an example of a target for distance measurement, adheres to the inner wall of the pipe 203 . The deposits 300 are clinker (sintered ash), and are produced by accumulating dust generated when combustible gas and char are burned in the melting furnace 201 . A distance measuring device 100 is used to monitor the thickness of deposits 300 adhering to the inner wall of pipe 203 . An arrangement position P<b>1 of the distance measuring device 100 is outside and above the pipe 203 .

Referring to FIGS. 1 and 3 , distance measuring device 100 includes main unit 1 , stereo camera 2 , bandpass filter 3 , light emitting unit 4 and housing 5 . Main unit 1 , stereo camera 2 , bandpass filter 3 and light emitting unit 4 are arranged inside housing 5 . A glass window portion 50 is formed on the front surface of the housing 5 .

The pipe 203 is formed with a port 7 through which the inside of the pipe 203 can be observed. Port 7 is sometimes referred to as a nozzle. The port 7 has a port body 71 and a flange 72 . Port body 71 is a short tubular member having a through hole 73 that communicates with tubing 203 . A flange 72 is formed around the upper end of the port body 71 . Rangefinder 100 is fixed to flange 72 with glass window 50 facing through hole 73 .

The stereo camera 2 is composed of two cameras 20 . Camera 20 is a visible light camera. A bandpass filter 3-1 is attached to the front surface of the lens 21-1 of the camera 20-1, and a bandpass filter 3-2 is attached to the front surface of the lens 21-2 of the camera 20-2. Details of the bandpass filter 3 will be described later.

The lens 21-1 of the camera 20-1 is arranged to face the glass window 50-1. The angle of view of the camera 20-1 is set inside the pipe 203 through the glass window 50-1 and the through hole 73. As shown in FIG. Similarly, the lens 21-2 of the camera 20-2 is arranged to face the glass window 50-2. The angle of view of the camera 20-2 is set inside the pipe 203 via the glass window 50-2 and the through hole 73. As shown in FIG.

When the deposit 300 exists in the angle of view (field of view) of the camera 20, the measured distance becomes shorter as the thickness of the deposit 300 increases. The difference between the distance measured without the deposit 300 inside the pipe 203 and the distance measured with the deposit 300 inside the pipe 203 is the thickness of the deposit 300 .

The light emitting unit 4 is, for example, a laser diode. The output of the light emitting section 4 is, for example, 40 mW. The wavelength of the light beam L emitted by the light emitting unit 4 is, for example, 520 nm. A light-emitting diode may be used instead of the laser diode.

The light emitting section 4 is arranged to face the glass window section 50-3. The light emitting unit 4 irradiates the measuring point P2 inside the pipe 203 with the light beam L through the glass window 50-3 and the through hole 73. As shown in FIG. The measurement point P2 is set within a range within the angle of view of the camera 20-1 and the angle of view of the camera 20-2. When the deposit 300 exists at the measurement point P2, the distance to the measurement point P2 decreases as the thickness of the deposit 300 increases. The difference between the distance to the measurement point P2 measured with no deposit 300 inside the pipe 203 and the distance to the measurement point P2 measured with the deposit 300 inside the pipe 203 is , the thickness of the deposit 300 .

Referring to FIG. 1, main unit 1 is a computer device that includes a control processing unit 10, a communication unit 11, a distance measurement unit 12, and a determination unit 13 as functional blocks. The control processing unit 10, the distance measurement unit 12 and the determination unit 13 are hardware processors. More specifically, these include hardware such as a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and HDD (Hard Disk Drive), and hardware for executing the functions of the above functional blocks. It is implemented by programs, data, and the like.

The control processing unit 10 is a device for controlling each unit (the communication unit 11, the distance measurement unit 12, the determination unit 13) of the main unit 1 according to the function of each unit.

The communication section 11 is a communication circuit for performing communication under the control of the control processing section 10 . The communication unit 11 communicates with a computer device 401 arranged in a central control room 400 that controls the gasification melting furnace 200 (FIG. 2). The communication unit 11 is implemented by a communication interface circuit.

The distance measurement unit 12 selectively performs the first distance measurement and the second distance measurement. The first ranging is ranging using the stereo camera 2 . Based on the image of the deposit 300 captured by the stereo camera 2, that is, the image of the deposit 300 captured by the camera 20-1 and the camera 20-1, the ranging unit 12 measures the deposit 300 by triangulation. Measure the distance to The distance measurement unit 12 calculates the thickness of the deposit 300 based on the measured distance.

The second ranging is ranging using the light beam L. FIG. One camera 20 of the light emitting unit 4 and the stereo camera 2 is used for the second distance measurement. One camera 20 captures an image of the reflected light from the light-emitting unit 4 that irradiates the measurement point P2 with the light beam L. The distance measuring unit 12 measures the distance to the measurement point P2 by triangulation based on the image of the reflected light. The distance measurement unit 12 calculates the thickness of the deposit 300 based on the measured distance.

The control processing unit 10 causes the communication unit 11 to transmit thickness information indicating the thickness of the deposit 300 calculated by the distance measuring unit 12 to the computer device 401 as a destination. The computer device 401 causes the display of the computer device 401 to display the thickness indicated by the received thickness information.

The determination unit 13 determines whether or not the first distance measurement can be performed based on the dust present in the space up to the deposit 300 . The distance measurement unit 12 executes the second distance measurement when the determination unit 13 determines that the first distance measurement cannot be performed, and performs the first distance measurement when the determination unit 13 determines that the first distance measurement can be performed. Perform ranging.

A positional relationship between the stereo camera 2 and the light emitting unit 4 will be described. FIG. 4 is a plan view of the port 7 viewed from above. 3 and 4, the diameter D of the through hole 73 formed in the port 7 is, for example, 80 mm, and the diameter of the port 7 including the flange 72 is, for example, 160 mm. The distance S between the camera 20-1 and the camera 20-2 constituting the stereo camera 2 is such that the camera 20-1 and the camera 20-2 can photograph the deposit 300 (distance measurement target) through the through hole 73. is set to the maximum value of the interval S.

The accuracy of distance measurement (first distance measurement) using the stereo camera 2 improves as the distance S between the two cameras 20 increases. The distance measuring device 100 is arranged outside the pipe 203 , and the two cameras 20 photograph deposits 300 inside the pipe 203 through the through holes 73 . Therefore, in order to ensure the respective fields of view of the two cameras 20, the distance S between the two cameras 20 is restricted by the diameter D of the through hole 73 and has an upper limit (maximum value). According to the embodiment, by setting the distance S to the maximum value, the precision of distance measurement using the stereo camera 2 is improved as much as possible.

A specific description will be given. The camera 20-1 is arranged on one side and the camera 20-2 is arranged on the other side with the center of the through-hole 73 in plan view as the center. The distance from the center to the camera 20-1 and the distance from the center to the camera 20-2 are each 40 mm (therefore, the distance S between the two cameras 20 is 80 mm). In this case, according to calculations, it was found that distance measurement using the stereo camera 2 (first distance measurement) can be performed with an error of about ±35 mm.

The light emitting unit 4 is arranged between the cameras 20-1 and 20-2 and at the center of the through hole 73 in plan view. The distance between the light emitting unit 4 and the camera 20-1 and the distance between the light emitting unit 4 and the camera 20-1 are each 40 mm. In this case, according to calculations, it was found that the error in distance measurement using the light beam L (second distance measurement) can be reduced to about ±100 mm.

A bandpass filter 3 (an example of an optical filter) will be described. FIG. 5 is a graph showing spectra measured inside pipe 203 (FIG. 2) during combustion inside melting furnace 201 . The horizontal axis of the graph indicates the wavelength of the spectrum. The left vertical axis of the graph indicates the spectral intensity output from the spectrometer. The right vertical axis of the graph indicates the spectral intensity output by the hyperspectral camera. Spectra were measured using a spectrometer and a hyperspectral camera.

Since the inside of the melting furnace 201 is at a high temperature, the inside of the piping 203 connected thereto is also at a high temperature. Therefore, the measured spectrum has high intensity in the red wavelength band and above. Therefore, the intensity of noise increases in the wavelength band equal to or higher than the red wavelength band. Also, there is a wavelength (for example, around 580 nm) showing a bright line caused by an element such as Na, which becomes noise. The bandpass filter 3 is transparent to a wavelength band (eg, 524 nm±46 nm) including the wavelength of the light beam L (eg, 520 nm), and cuts other wavelength bands. Therefore, the image of the deposit 300 captured by the stereo camera 2 (cameras 20-1 and 20-2) and the reflected light image captured by one of the cameras 20 constituting the stereo camera 2 are Each can improve the SN ratio.

1 and 3, determination unit 13 compares an index value indicating the concentration of dust floating inside pipe 203 with a predetermined threshold value, and determines whether the index value exceeds the threshold value. When the index value exceeds the threshold value, it is determined that the first distance measurement cannot be performed, and when the index value is equal to or less than the threshold value, it is determined that the first distance measurement can be performed. The index value is based on the number of pixels constituting the edge of the deposit 300 captured in the image detected by the edge detection of the image of the deposit 300 captured by the stereo camera 2 .

Explain the metric value in detail. FIG. 6 is an image diagram showing an image Im1 inside the pipe 203 captured by the stereo camera 2 in a state where the concentration of dust floating inside the pipe 203 is low. 3 and 6, image Im1-1 is an image captured by camera 20-1 (left camera). Image Im1-2 is an image captured by camera 20-2 (right camera). Since the image Im1 is captured through the through hole 73, the portion of the interior of the pipe 203 facing the through hole 73 is shown. Since the deposits 300 deposited on this portion appear in the image Im1, this portion is defined as an area 301 where the deposits 300 are deposited (an area where the object for distance measurement occurs). Deposits 300 are deposited over the entire area 301 . If no deposit (not shown) is deposited on the inner wall of the through hole 73, the shape of the area 301 will be circular. If a deposit (not shown) is deposited on the inner wall of the through-hole 73, the shape of the area 301 will not be circular, but will have a distorted shape reflecting the shape of this deposit.

When the concentration of dust floating inside the pipe 203 (dust floating in the space up to the object of distance measurement) is low, the image Im1 captured by the stereo camera 2 reflects the uneven shape of the deposit 300, and the uneven shape A deposit 300 having A portion 302 of the deposit 300 photographed in the image Im1-1 and a portion 303 of the deposit 300 photographed in the image Im1-2 are the same. Portions 302 and 303 of the deposit 300 have been processed to be surrounded by white dotted lines for better visibility.

On the other hand, when the density of the dust floating inside the pipe 203 is high, the uneven shape of the deposit 300 is not reflected in the image Im1 captured by the stereo camera 2, and the deposit 300 is flat. This is shown in FIG. FIG. 7 is an image diagram showing an image Im1-3 inside the pipe 203 captured by one camera 20-1 (left camera) of the stereo camera 2 in a state where the concentration of dust floating inside the pipe 203 is high. be. In the image Im1-3, the uneven shape of the surface of the deposit 300 is hardly captured. Note that the images Im1-3 were taken in a state in which the light beam L was applied to the deposit 300 by the light emitting unit 4, and the reflected light RL of the light beam L was captured.

The inventors have found that the number of pixels constituting the edge of the deposit 300 captured in the image Im1 detected by edge detection for the image Im1 of the deposit 300 captured by the stereo camera 2 and the density of the dust are positively correlated. found to be related. Therefore, an index value indicating the density of dust can be determined based on the number of pixels. The determination unit 13 uses this index value to determine whether or not the first distance measurement can be performed.

An example of index values will be described. Let n1 be the number of pixels forming the edge of the deposit 300 (object of distance measurement) detected by edge detection, and the number of pixels forming the area of area 301 (area where the object of distance measurement occurs) captured in image Im1. is n2, the number of pixels forming an edge detected by edge detection is n3, and the number of pixels forming an edge showing the shape (outline) of area 301 detected by edge detection is n4, the index The value is shown by the following formula.
n1=n3-n4
Index value = n1/n2

A process for calculating this index value will be described. FIG. 8 is a flow chart explaining this process. 1 and 8, determination unit 13 binarizes an image Im1 (not shown) of deposit 300 captured by one camera 20 of stereo camera 2 (step S1). . As a result, a binarized image Im2 is generated. FIG. 9 is an image diagram showing an example of the image Im2.

The determination unit 13 performs edge detection processing on the image Im2 (step S2). As a result, an image Im3 that has undergone edge detection processing is generated. FIG. 10 is an image diagram showing an example of the image Im3. Within area 301, multiple edges 304 of deposit 300 are detected. The number of pixels forming these edges 304 is n1. In addition, a line indicating the shape (outline) of area 301 is also detected as edge 305 . The number of pixels forming the edge 305 is n4. Therefore, the number n3 of pixels forming an edge detected by edge detection is n1+n4 (that is, n1=n3-n4).

The determination unit 13 removes the edge 305 from the image Im3 (step S3). This produces an image Im4 showing the edge 304 of the deposit 300 . FIG. 11 is an image diagram showing an example of the image Im4.

The determination unit 13 counts the number n1 of pixels forming the edge 304 of the deposit 300 shown in the image Im4 shown in FIG. is counted (step S4).

The determination unit 13 calculates an index value (=n1/n2) (step S5).

Next, the operation of rangefinder 100 will be described. FIG. 12 is a flow chart explaining this operation. Referring to FIGS. 1 and 12, when rangefinder 100 is instructed to start rangefinding, determination unit 13 calculates an index value (step S11). This was explained in FIG. The determination unit 13 determines whether or not the index value exceeds a predetermined threshold (step S12).

When the determination unit 13 determines that the index value is equal to or less than the threshold value (No in step S12), the distance measurement unit 12 executes first distance measurement (distance measurement using the stereo camera 2) (step S13). ). The distance measurement unit 12 determines whether or not an instruction to end the distance measurement has been issued (step S14). When the distance measuring unit 12 determines that an instruction to end the distance measurement has been issued (Yes in step S14), the distance measurement ends (step S15). When the distance measuring unit 12 determines that the instruction to end the distance measurement has not been issued (No in step S14), the distance measuring device 100 returns to the process of step S11.

When the determination unit 13 determines that the index value exceeds the threshold value (Yes in step S12), the distance measurement unit 12 executes second distance measurement (distance measurement using the light beam L). (Step S16), the distance measuring device 100 executes step S14.

Main effects of the embodiment will be described. Referring to FIG. 3, the inventor focused on dust floating in pipe 203 (the space up to the object of distance measurement). The first distance measurement (distance measurement using the stereo camera 2) has the advantage of a wide distance measurement range, but has the disadvantage of being easily affected by dust present in the pipe 203 (when the concentration of dust increases, the measurement becomes more difficult). distance becomes impossible). The second distance measurement (distance measurement using the light beam L) has the advantage of being less susceptible to dust floating in the pipe 203 (distance can be measured even if the concentration of dust is high). It has the disadvantage of having a narrow range.

Referring to FIGS. 3 and 12, distance measuring apparatus 100 executes second distance measurement when it is determined that the first distance measurement cannot be performed due to dust floating in pipe 203 (Yes in step S12). (Step S16) When it is determined that the first distance measurement can be performed (No in step S12), the first distance measurement is performed (step S13). Therefore, according to the embodiment, ranging using the stereo camera 2 and ranging using the light beam L can be selectively used according to the environment in which the deposit 300 (target for ranging) is placed.

When the distance measuring device 100 is arranged inside the pipe 203 (product), equipment for cooling the distance measuring device 100 (cooling pipe, etc.) also needs to be arranged inside the pipe 203 . In this case, since the distance measuring device 100 and the equipment for cooling it are arranged inside the pipe 203, it takes time and effort to maintain them. According to the embodiment, the distance measuring device 100 and the equipment (not shown) for cooling it are arranged outside the pipe 203, so maintenance thereof is not troublesome.

When the distance measuring device 100 is arranged inside the pipe 203 , deposits 300 adhering to the distance measuring device 100 may obstruct the field of view of the stereo camera 2 . According to the embodiment, the ranging device 100 is arranged outside the pipe 203, so this does not occur.

2 Stereo camera 20 (20-1, 20-2) Camera 3 (3-1, 3-2) Bandpass filter 4 Light emitting unit 7 Port (nozzle)
71 Port main body 72 Flange 73 Through hole 100 Rangefinder 203 Piping 300 Deposits (an example of a target for range measurement)
301 deposit area 302, 303 deposit portion 304, 305 edge D through-hole diameter L light beam P1 placement position P2 measurement point RL reflected light S distance between two cameras

Claims (7)

a stereo camera,
a light emitting unit;
first distance measurement for measuring the distance to the distance measurement target based on the image of the distance measurement target captured by the stereo camera; a distance measurement unit that selects and executes a second distance measurement that measures the distance to the distance measurement object based on the reflected light that has been received;
a determination unit that determines whether or not the first distance measurement can be performed based on dust existing in the space up to the distance measurement target,
The distance measurement unit executes the second distance measurement when it is determined that the first distance measurement cannot be performed, and performs the first distance measurement when it is determined that the first distance measurement is possible. and run
The determination unit compares an index value indicating the density of the dust with a predetermined threshold value, and determines that the first distance measurement cannot be performed when the index value exceeds the threshold value. determining that the first distance measurement can be performed when the index value is equal to or less than the threshold;
The distance measuring device, wherein the index value is based on the number of pixels forming an edge of the object of distance measurement in the image, which is detected by edge detection on the image. Let n1 be the number of pixels forming the edge of the target for distance measurement detected by the edge detection, n2 be the number of pixels forming the area of the area in which the target for distance measurement is generated in the image, and n2 be the number of pixels forming the edge. When the number of pixels forming an edge detected by detection is n3, and the number of pixels forming an edge showing the shape of the area detected by the edge detection is n4, the index value is expressed by the following formula. 2. The range finder of claim 1, wherein
n1=n3-n4
Index value = n1/n2 The distance measuring device is arranged outside the product, which is at least one of a garbage incinerator and a pipe connected to the garbage incinerator, through a through hole provided in the product that leads to the inside of the product, 2. The range finder according to claim 1 , which measures the distance to said range-finding object generated inside said range finder. a stereo camera,
a light emitting unit;
first distance measurement for measuring the distance to the distance measurement target based on the image of the distance measurement target captured by the stereo camera; a distance measurement unit that selects and executes a second distance measurement that measures the distance to the distance measurement object based on the reflected light that has been received;
a determination unit that determines whether or not the first distance measurement can be performed based on dust present in a space up to the distance measurement target, the distance measuring device comprising:
The distance measurement unit executes the second distance measurement when it is determined that the first distance measurement cannot be performed, and performs the first distance measurement when it is determined that the first distance measurement is possible. and run
The distance measuring device is arranged outside the product, which is at least one of a garbage incinerator and a pipe connected to the garbage incinerator, through a through hole provided in the product that leads to the inside of the product, A ranging device that measures a distance to the ranging object generated inside the device. The distance between one camera and the other camera constituting the stereo camera is the maximum value of the distance at which the one camera and the other camera can photograph the range-finding object through the through hole. 5. The rangefinder according to claim 4, wherein The light emitting unit irradiates the range-finding object with the light beam having a wavelength included in a wavelength band shorter than the wavelength band of red,
The distance measuring device further comprises an optical filter disposed between the stereo camera and the through hole, having transparency to the wavelength of the light beam, and cutting the red wavelength band or higher,
The second distance measuring unit measures the distance to the distance measuring object by a triangulation method based on the image of the reflected light captured by one of the cameras constituting the stereo camera. 6. A ranging device according to claim 4 or 5, for performing ranging. A first distance measurement for measuring the distance to the distance measurement object based on the image of the distance measurement object taken by the stereo camera, and a light emitting unit irradiating the distance measurement object with a light beam, a second distance measurement for measuring the distance to the distance measurement target based on the reflected light obtained from the distance measurement method, wherein
a determination step of determining whether or not the first distance measurement can be performed by dust existing in the space up to the distance measurement target;
a ranging step of performing the second ranging when it is determined that the first ranging cannot be performed, and performing the first ranging when it is determined that the first ranging can be performed; and
The determining step compares an index value indicating the density of the dust with a predetermined threshold value, and determines that the first distance measurement cannot be performed when the index value exceeds the threshold value. determining that the first distance measurement can be performed when the index value is equal to or less than the threshold;
The distance measurement method according to claim 1, wherein the index value is based on the number of pixels forming an edge of the distance measurement object appearing in the image, detected by edge detection for the image.

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