JP2022138192A - Disturbance presence/absence determination device, method, and program - Google Patents

Abstract

To provide a technique for determining whether disturbance is present or absent in distance measurement.SOLUTION: A disturbance presence/absence determination device includes: an acquisition unit that acquires measurement results including a distance to a marker from a 3D distance sensor, with the marker placed at a known distance from the 3D distance sensor and within an angle of view of the 3D distance sensor; and a determination unit that determines whether or not there is a disturbance that causes a measurement error by the 3D distance sensor, based on the measurement results and the distance being acquired.SELECTED DRAWING: Figure 7

Description

The present invention relates to a disturbance presence/absence determination device, method, and program.

2. Description of the Related Art Distance sensors are used to detect objects such as human bodies in situations where monitoring is required, such as production sites. In order to reliably detect an object in the monitored area, it is required to install the distance sensor in an appropriate position and orientation. However, it is not easy for the user to determine whether the installation position of the distance sensor is appropriate.

US Pat. No. 6,200,000 discloses a system that uses 3D sensors to monitor a workspace for safety purposes. The system aligns the 3D sensors with respect to each other, for example, by comparing the image from each sensor with the images from the other sensors and identifying correspondences in those images. According to Patent Document 1, it can be seen that the 3D sensor is not arranged at an appropriate position.

Japanese Patent Publication No. 2020-511325

However, in Patent Document 1, it is not known whether or not the current sensor placement position is a position where there is a disturbance that affects the measurement results of the sensor. Therefore, in order for the user to determine whether the installation position and orientation of the distance sensor are appropriate, it is necessary to grasp the presence or absence of disturbances that may cause measurement errors. The applicant considered examples of the above-described disturbances to be multipaths caused by reflection of light or the like outside the object of measurement, high reflectors at short distances, external light, dust, or vibrations.

An object of the present invention is to provide a technique for determining the presence or absence of disturbance in distance measurement.

In order to achieve the above objects, the present invention employs the following configurations.

In a first aspect of the present invention, a marker is placed at a known distance from a three-dimensional distance sensor, and the marker is within the angle of view of the three-dimensional distance sensor. acquisition means for acquiring a measurement result including a distance; and based on the measurement result acquired by the acquisition means and the known distance, whether or not there is a disturbance that causes a measurement error by the three-dimensional distance sensor. and determination means for determination.

A "three-dimensional distance sensor" is, for example, a TOF (Time of Flight) sensor.

According to this configuration, the marker is placed at a known distance from the three-dimensional distance sensor, and the distance to the marker obtained by the three-dimensional distance sensor is included when the marker is within the angle of view of the three-dimensional distance sensor. Based on the measurement result and the known distance, it is determined whether or not there is a disturbance that causes measurement error by the three-dimensional distance sensor. This makes it possible to determine the presence or absence of disturbance in three-dimensional distance measurement. Examples of the disturbance include multipath caused by reflection of light or the like outside the object of measurement, highly reflective objects at a short distance, external light, dust, vibration, and the like.

For example, the three-dimensional distance sensor is a sensor that obtains distance information to the measurement target based on light reflected by the measurement target, and the determination means determines that the distance to the marker is longer than the known distance. If the measurement result indicates, it may be determined that there is disturbance due to multipath caused by reflection outside the object of measurement.

Further, the three-dimensional distance sensor is a sensor that obtains distance information to the measurement target based on light reflected by the measurement target, and the measurement result includes light amount information at each position within the angle of view, and the determination If the measurement result indicates that the distance to the marker is shorter than the known distance and there is a position other than the marker within the angle of view where the light intensity exceeds a first threshold light intensity, , it may be determined that there is a disturbance due to a high reflector at a short distance.

In addition, the measurement result includes light amount information at each position within the angle of view, and the determining means detects a position other than the marker within the angle of view where the light amount exceeds a second threshold light amount. may be determined that there is disturbance due to external light.

Further, the determination means may determine that there is disturbance due to dust when the distance to the marker indicated by the measurement result changes by exceeding a first threshold distance within a first predetermined time.

Further, the determining means determines that there is disturbance due to vibration when the position of the marker within the angle of view indicated by the measurement result changes by exceeding a second threshold distance within a second predetermined time. good too.

In a second aspect of the present invention, two markers are arranged at a known interval, and in a state in which the two markers are within the angle of view of the three-dimensional distance sensor, the distance between the two markers by the three-dimensional distance sensor Obtaining means for obtaining measurement results including each distance, and based on the measurement results obtained by the obtaining means and the known distance, whether or not there is a disturbance that causes a measurement error by the three-dimensional distance sensor. A disturbance presence/absence determination device characterized by having determination means for determining

According to this configuration, the two markers are arranged at a known interval, and each distance to the two markers by the three-dimensional distance sensor is obtained in a state in which the two markers are within the angle of view of the three-dimensional distance sensor. Based on the measurement result including , and the known distance, it is determined whether or not there is a disturbance within the angle of view that causes a measurement error by the three-dimensional distance sensor.

For example, the three-dimensional distance sensor is a sensor that obtains distance information to the object to be measured based on light reflected by the object to be measured, and the determination means determines the distances to the two markers acquired by the acquisition means. If the calculated spacing between the two markers does not match the known spacing, multipath caused by reflections outside the measurement target, short-range high It may be determined that there is disturbance due to either a reflector or dust.

Further, the determination means calculates the distance between the two markers based on the respective distances to the two markers acquired by the acquisition means, and the calculated distance between the two markers is a third predetermined distance. If the change exceeds the third threshold distance within the time, it may be determined that there is disturbance due to dust.

Further, the determination means determines that when at least one of the distances to the two markers acquired by the acquisition means changes by exceeding a fourth threshold distance within a fourth predetermined time, disturbance due to dust is detected. It may be determined that there is

Further, the three-dimensional distance sensor is a sensor that obtains distance information to the measurement target based on light reflected by the measurement target, and the measurement result includes light amount information at each position within the angle of view, and the determination If there is a position other than the two markers within the angle of view where the amount of light exceeds the threshold amount of light, the means determines that there is disturbance due to either a short-distance high reflector or external light. may

In addition, if the position of at least one of the two markers indicated by the measurement result within the angle of view changes by exceeding a fifth threshold distance within a fifth predetermined time, the determination means detects disturbance due to vibration. It may be determined that there is

Moreover, it may have a notification means for notifying the result of determination by the determination means. Also, the three-dimensional distance sensor may be a TOF sensor.

In a third aspect of the present invention, a marker is placed at a known distance from a three-dimensional distance sensor, and the marker is within the angle of view of the three-dimensional distance sensor. an acquisition step of acquiring a measurement result including a distance; and based on the measurement result acquired by the acquisition step and the known distance, whether or not there is a disturbance that causes a measurement error by the three-dimensional distance sensor. and a determining step for determining the presence or absence of disturbance.

In a fourth aspect of the present invention, two markers are arranged at a known interval, and in a state where the two markers are within the angle of view of the three-dimensional distance sensor, the distance between the two markers by the three-dimensional distance sensor An acquisition step of acquiring a measurement result including each distance, and whether or not there is a disturbance that causes a measurement error by the three-dimensional distance sensor based on the measurement result acquired by the acquisition step and the known distance. and a determination step for determining the presence or absence of a disturbance.

A fifth aspect of the present invention provides a program for causing a computer to execute each step of the disturbance presence/absence determination method described above.

The present invention may be regarded as a disturbance presence/absence determination device, a disturbance presence/absence determination system, or a disturbance presence/absence determination method having at least part of the above means. Further, the present invention can also be regarded as a program for realizing such a method and a recording medium on which the program is non-temporarily recorded. It should be noted that each of the means and processes described above can be combined with each other as much as possible to constitute the present invention.

According to the present invention, it is possible to determine the presence or absence of disturbance in distance measurement.

FIG. 1 is a block diagram of a determination system including a disturbance presence/absence determination device according to an embodiment of the present invention. FIG. 2 is a schematic side view of the site where the presence or absence of disturbance is determined. FIG. 3 is a schematic plan view of the site where the presence or absence of disturbance is determined. FIG. 4 is a diagram showing a display example of a luminance image. FIG. 5 is a functional block diagram of the controller. FIG. 6 is a schematic diagram of the sensor. FIG. 7 is a flowchart showing sensor installation processing and disturbance determination processing. FIG. 8 is a schematic diagram of a marker body including a pair of markers.

<Application example>
An application example of a disturbance presence/absence determination apparatus according to the present invention will be described with reference to FIGS. 1 to 5. FIG. FIG. 1 is a block diagram of a determination system including a disturbance presence/absence determination device 50 according to an embodiment of the present invention. 2 and 3 are a schematic side view and a plan view, respectively, of a site where the presence or absence of disturbance is determined. FIG. 4 is a diagram showing a display example of a luminance image. FIG. 5 is a functional block diagram of the controller. The direction of each part is referred to with reference to the X, Y, and Z coordinate axes shown in FIGS. As viewed from the sensor 10, the front is the +Y direction, the top is the +Z direction, and the right is the +X direction.

The site shown in FIGS. 2 and 3 is assumed to be a place where objects need to be monitored, such as a production site where a danger source 13 such as a robot cooperates with workers to produce. A hazard 13 is installed on the workbench 12 . A virtual danger area 14 is set around or near the danger source 13 in consideration of the range of motion of the danger source 13 . A three-dimensional distance sensor 10 (hereinafter referred to as sensor 10) is installed to detect an object such as a human body before it approaches the dangerous area 14. FIG. The monitoring area of the three-dimensional distance sensor 10 can be set arbitrarily. For example, the 360-degree perimeter of the danger area 14 may be a surveillance area, or if the access direction to the danger source is limited (for example, a safety fence is provided or an obstacle exists), the surveillance area is limited. It is also possible to make only the range covered by the monitoring area a monitoring area. In the example of FIG. 2, only the front (+Y direction) of the dangerous area 14 is set as the monitoring area. Note that the monitoring area may be set so as to include the dangerous area 14 or may be set so as not to include the dangerous area 14 . In order to ensure the reliability of object detection, it is necessary to exclude factors that may cause disturbances in the measurement from the angle of view of the sensor 10 and its surroundings. This is because disturbances may affect measurement results and cause errors.

Therefore, in the first technique (first embodiment), as shown in FIGS. 2 and 3, the user places the marker 16 on the floor 11 at a known distance L1 from the sensor 10, and the marker 16 is within the angle of view 15 of the sensor 10 . In this state, the acquisition unit 38 ( FIG. 5 ) of the control unit 30 as acquisition means acquires the measurement result including the distance L1x measured by the sensor 10 to the marker 16 . Then, the determination unit 39 (FIG. 5) of the control unit 30 as determination means determines whether there is disturbance within the angle of view 15 that causes measurement error by the sensor 10 based on the obtained measurement result and the known distance L1. Determine whether or not there is

Here, since the sensor 10 is arranged above the dangerous area 14, the actual distance from the sensor 10 to the marker 16 is the length in the direction inclined with respect to the floor surface 11 (from the original position of the sensor 10 to the marker 16 straight line distance to However, the control unit 30 handles the actual distance by converting it into a distance L1 and a measured distance L1x, which are lengths in the Y direction parallel to the floor surface 11 . In addition, you may compare linear distances without converting into the length in a Y direction.

Examples of the disturbance include multipath caused by reflection of light or the like outside the object of measurement, highly reflective objects at a short distance, external light, dust, vibration, and the like. FIG. 3 shows that the reflection wall 17 is within the angle of view 15 of the sensor 10 as a factor of multipath. In addition, it is shown that the high reflector 18 and the external light 19 at a short distance are within the angle of view 15 . FIG. 4 shows a luminance image obtained in such a situation. In addition, although a plurality of disturbance factors are displayed in FIG. 4, it is sufficiently assumed that there is any one disturbance factor.

As shown in FIG. 1 , the sensor 10 includes a light emitter 41 , a light receiver 42 and a calculator 43 . The light emitting portion 41 emits light (for example, infrared light), and the light receiving portion 42 receives reflected light. The sensor 10 employs, for example, a TOF sensor that acquires a range image from the time of flight (TOF) of light. For example, an indirect TOF sensor that estimates the time difference from the phase difference between projected light and reflected light is employed. The sensor 10 outputs three-dimensional distance information and luminance information as measurement results. The measurement results obtained by the sensor 10 include light amount information at each position within the angle of view 15 . A measurement result is supplied to the control unit 30 via the sensor I/F 44 in the disturbance presence/absence determination device 50 . Sensor 10 is controlled by control unit 30 via sensor I/F 44 .

When the controller 30 detects that an object such as a human body has entered the angle of view 15 from the measurement result of the sensor 10, the controller 30 performs safety control such as low speed driving or stopping of the danger source. Further, the control unit 30 determines the presence or absence of disturbance from the measurement result, and if there is disturbance, determines the disturbance factor by utilizing the fact that the measurement result differs depending on the disturbance factor. A notification unit 40 (FIG. 5) of the control unit 30 as notification means notifies the determination result of the presence/absence of disturbance and, if there is a disturbance, the factor of the disturbance.

An example of a technique for determining the presence or absence of disturbance and a disturbance factor will be outlined (details will be described later). In the first method (first embodiment), for example, when the measurement result indicates that the measured distance L1x to the marker 16 is longer than the known distance L1, the control unit 30 detects multipath (reflecting wall 17 It is determined that there is a disturbance due to the reflection at the

If the measurement result indicates that the measured distance L1x is shorter than the distance L1 and there is a position other than the marker 16 within the angle of view 15 where the light intensity exceeds the first threshold light intensity, the control unit 30 determines that the short distance It is determined that there is a disturbance due to the high reflector (high reflector 18).

If there is a position other than the marker 16 within the angle of view 15 where the amount of light exceeds the second threshold amount of light, the control unit 30 determines that there is disturbance due to external light (external light 19). The control unit 30 determines that there is disturbance due to dust when the measured distance L1x changes by exceeding the first threshold distance within the first predetermined time. If the position of the marker 16 within the angle of view 15 changes beyond the second threshold distance within the second predetermined time, the control unit 30 determines that there is disturbance due to vibration.

In addition, a second method (second embodiment) may be adopted instead of the first method. This will be described later with reference to FIG.

The above application examples are examples to aid understanding of the present invention, and are not intended to limit interpretation of the present invention.

[First embodiment]
Next, the configuration of the disturbance presence/absence determination device 50 and the procedure for installing the sensor 10, etc., according to the first embodiment of the present invention will be described in detail. First, the configuration of the disturbance presence/absence determination device 50 will be described with reference to FIG. The disturbance presence/absence determination device 50 includes a control section 30 , a sensor I/F 44 , a display section 34 , an operation input section 35 , a storage section 36 and a communication I/F 37 . The control unit 30 includes a CPU 31, a ROM 32, a RAM 33, a timer (not shown), and the like. A control program executed by the CPU 31 is stored in the ROM 32 . The ROM 32 also stores values such as various threshold values. The RAM 33 provides a work area when the CPU 31 executes the control program.

The display unit 34 is configured by an LCD or the like, and displays various information. The display unit 34 may have two or more screens, or may have a function of displaying two or more screens by dividing the screen. The operation input unit 35 receives input of various instructions from the user and sends input information to the CPU 31 . Further, the operation input unit 35 may have a function of notifying the user by voice, lamp, or the like based on instructions from the CPU 31 . The storage unit 36 is composed of, for example, a non-volatile memory. The storage unit 36 may be an external memory. Communication I/F 37 performs wired or wireless communication between control unit 30 and an external device.

As shown in FIG. 5, the control unit 30 has an acquisition unit 38, a determination unit 39, and a notification unit 40. Each of these functions is implemented in software by a program stored in the ROM 32 . In other words, each function is provided by the CPU 31 developing necessary programs in the RAM 33 and executing them to perform various calculations and control of each hardware resource. In other words, the function of the acquisition unit 38 is realized mainly by cooperation of the CPU 31, ROM 32, RAM 33, and sensor I/F 44. The function of the determination unit 39 is realized mainly by cooperation of the CPU 31, the ROM 32 and the RAM 33. FIG. The function of the notification unit 40 is realized mainly by cooperation of the CPU 31, the ROM 32, the RAM 33, and the operation input unit 35. FIG.

As shown in FIG. 2, the marker 16 is, for example, a three-dimensional object that is easy to place, but the shape of the marker 16 is not limited and may be planar. The higher the brightness of the marker 16, the better. The reference surface on which the marker 16 is placed is not limited to the floor surface 11, and may be a flat surface such as a desk surface.

Next, a method for determining the presence or absence of disturbance and a disturbance factor in the present embodiment will be described in detail. The control unit 30 compares the measured distance L1x to the marker 16 indicated by the measurement result with the known distance L1, and determines that there is disturbance due to multipath when the measured distance L1x is longer than the distance L1. Here, a threshold for determination may be used in the comparison between the measured distance L1x and the distance L1, and the control unit 30 determines that the measured distance L1x is equal to the distance L1 when "measured distance L1x = distance L1 + predetermined value" is established. It may be determined to be longer. This predetermined value is set to a value larger than the error of the measured distance L1x that can occur when there is no disturbance, and this value is stored in the ROM 32 in advance.

Consider a case where a reflecting wall 17 is present within an angle of view 15 as shown in FIG. Assume that the reflecting wall is located at a position laterally displaced from the straight line connecting the sensor 10 and the marker 16 . Originally, the light emitted from the light emitting section 41 of the sensor 10 is directly reflected by the marker 16 which is the object to be measured, and is received by the light receiving section 42 . If only the direct light reflected by the marker 16 is received, the measured distance L1x will be equal to the distance L1. However, part of the light emitted from the light emitting section 41 may be reflected by the marker 16 via the reflecting wall 17 and received. The path through the reflecting wall 17 is longer than the straight path between the sensor 10 and the marker 16 . Therefore, the timing of receiving the light that has passed through the reflecting wall 17 is delayed compared to the light that has not passed through the reflecting wall 17 . As a result, the measured distance L1x may become longer than the distance L1. Under these circumstances, it can be determined that there is disturbance due to multipath when the measured distance L1x is longer than the distance L1. Regarding multipath, the degree of influence on the marker 16 can change depending on the position of the reflecting wall 17 . In other words, in the arrangement example of FIG. 3, it is possible to find the occurrence of multipath due to the reflecting wall 17 from the variation in the measurement distance of the marker 16, but it is not always possible to find the multipath-causing object at other positions. do not have. Therefore, in practical use, it is desirable to change the position of the marker 16 and perform multiple measurements to find and deal with all multipath-causing objects inside and outside the monitored area.

Next, as shown in FIG. 3, consider the case where the high reflector 18 is near the sensor 10 within the angle of view 15 . The high reflector 18 is, for example, an object that is always placed, or a worker's foot or the like. When the high reflector 18 is positioned sufficiently closer to the sensor 10 than the marker 16 , strong reflected light from the high reflector 18 is received by the sensor 10 . Therefore, from the measurement result, if the measured distance L1x is shorter than the distance L1 and there is a position other than the marker 16 within the angle of view 15 where the light intensity exceeds the first threshold light intensity, the controller 30 determines that the short distance It is determined that there is a disturbance due to the high reflector 18 of . The reason for this determination will be explained with reference to FIG.

FIG. 6 is a schematic diagram of the sensor 10. As shown in FIG. The sensor 10 has a lens 20 as an optical system. The light 22 from the marker 16 passes through the lens 20 and is received by the light receiving section 42 . If only the light 22 is received, the measured distance L1x is equal to the distance L1. However, the light 23 reflected by the high reflector 18 may pass through the lens 20 and be received by the light receiving section 42 through internal reflection between the light receiving section 42 and the lens 20 . In this case, the light receiving timings of the internally reflected light 23 and the light 22 from the marker 16 are shifted. As a result, the distance as a measurement result becomes shorter than the original distance. Moreover, since the high reflector 18 is located near the sensor 10, the portion corresponding to the high reflector 18 is bright in the luminance image shown in FIG. Therefore, when the amount of light in the portion corresponding to the high reflector 18 exceeds the first threshold amount of light, it can be determined that there is disturbance due to the high reflector 18 at a short distance.

Next, as shown in FIG. 3, consider the case where the external light 19 exists at a position other than the marker 16 within the angle of view 15 . The control unit 30 determines that there is disturbance due to the external light 19 when the amount of light at the position corresponding to the external light 19 exceeds the second threshold amount of light on the brightness screen shown in FIG. This is because the presence of the external light 19 may cause errors in the measurement results. Here, the second threshold light amount is set based on a value assumed as the light amount of the portion corresponding to the marker 16, and the value is stored in the ROM 32 in advance. For example, the second threshold light intensity is a value larger than the assumed light intensity of the portion corresponding to the marker 16 .

Next, as another disturbance, consider dust (not shown) fluttering at the site. The control unit 30 continuously acquires the measurement result for at least the first predetermined time. Then, if the measured distance L1x obtained from the measurement result changes beyond the first threshold distance within the first predetermined time, the control unit 30 determines that there is disturbance due to dust. This is because dust may cause an error in the measurement result. For example, when light reflected by dust moving across the marker 16 is received by the sensor 10, the measured distance L1x is temporarily calculated as a short value. It will be detected that there is an object in Here, the first threshold distance is set to a value larger than the error of the measured distance L1x that can occur when there is no disturbance, and that value is stored in the ROM 32 in advance. The first predetermined time is stored in the ROM 32, and its value is not limited. It should be noted that frequent crossings by workers and machines are also detected as disturbances in the same way as dust.

Next, consider the case where there is vibration in the field as another disturbance. This vibration is assumed to be shaking caused by other machines, but it is also assumed that the location where the sensor 10 is attached is shaking. The control unit 30 continuously acquires the measurement result for at least the second predetermined time. Then, if the position of the marker 16 (two-dimensional coordinates on the screen) within the angle of view 15 obtained from the measurement result changes by exceeding the second threshold distance within the second predetermined time, the control unit 30 detects the It is judged that there is a disturbance. This is because if there is vibration, the position of the marker 16 relative to the sensor 10 changes in small increments, which may cause an error in the measurement result. Here, the second threshold distance is set to a value larger than the error of the measured distance L1x that can occur when there is no disturbance, and this value is stored in the ROM 32 in advance. The second predetermined time is stored in the ROM 32, and its value is not limited.

In the present embodiment, the detectable disturbances are assumed to be multipaths, high reflectors at a short distance, external light, dust, and vibrations, but a plurality of possible disturbances among these may be combined and used as detection targets. For example, it is possible to combine two or more of multipath, a high reflector at a short distance, dust, and vibration, and detect them in parallel. Alternatively, it is possible to combine two or more of multipath, external light, dust, and vibration and detect them in parallel.

Next, sensor installation processing and disturbance determination processing will be described according to the flowchart of FIG. FIG. 7 is a flowchart showing sensor installation processing and disturbance determination processing. This sensor installation processing is executed by the user. The disturbance determination process is realized by the CPU 31 developing a program stored in the ROM 32 in the RAM 33 and executing the program. The disturbance determination process is started by a user's instruction, and is executed by the CPU 31 in parallel with the sensor installation process.

First, in step S<b>101 , the user places the marker 16 on the floor 11 at a known distance L<b>1 from the sensor 10 . Note that if the marker 16 has already been placed, the user may set the marker 16 again. In step S102, the user installs the sensor 10 or, if installed, adjusts its position as needed. The user determines the position and orientation of the sensor 10 so that the marker 16 is within the angle of view 15 (within the field of view) of the sensor 10 . In step S103, the user instructs the CPU 31 to perform distance measurement by the sensor 10 (distance measurement instruction). Distance measurement here includes acquisition of luminance information as well as distance information.

On the other hand, in step S201, the CPU 31 waits for a distance measurement instruction from the user, and when there is a distance measurement instruction, the process proceeds to step S202. In step S202, the CPU 31 causes the sensor 10 to perform distance measurement. A measurement result is supplied from the sensor 10 to the CPU 31 . When the CPU 31 obtains the measurement result for a certain period of time, in step S203, the CPU 31 executes determination processing of the presence or absence of disturbance and its factor based on the measurement result and the known distance L1. That is, the presence or absence of disturbance is determined using various methods for determining the presence or absence of disturbance and the disturbance factor described above, and when it is determined that there is disturbance, the factor is also determined.

In step S204, the CPU 31 determines whether or not it is determined by the determination processing in step S203 that there is a disturbance. Then, when it is not determined that there is a disturbance, the CPU 31 performs OK notification in step S207. For example, the CPU 31 displays a notification such as a message indicating that there is no disturbance on the display unit 34 . On the other hand, when it is determined that there is a disturbance, the CPU 31 performs error notification in step S205. In this error notification, for example, the CPU 31 displays, on the display unit 34, a notification such as a message indicating that there is a disturbance and the cause of the disturbance. In the OK notification and the error notification, voice notification may be performed in place of or in combination with the display.

In step S104, the user receives the notified content, and if it determines that there is no disturbance and that there is no problem with the current installation position of the sensor 10, inputs an OK instruction indicating that the disturbance determination process is to be terminated. If you want to redo the installation without the

On the other hand, after steps S205 and S207, in step S206, the CPU 31 waits for an OK instruction or a redo instruction from the user. If an instruction to redo is input, the process returns from step S105 to step S101 and from step S206 to step S201. Therefore, in this case, the user can redo the placement of the marker in step S101, and furthermore can perform the process of removing the disturbance. In step S102, installation of the sensor 10 can be redone. The disturbance presence/absence determination device 50 waits for a distance measurement instruction and executes distance measurement again.

If the OK instruction is input, the processing shown in FIG. 7 ends. In this case, the CPU 31 can shift to subsequent processing such as object detection and safety control.

According to the present embodiment, the control unit 30 (acquisition unit 38) controls the sensor 10 in a state in which the marker 16 is arranged at a known distance L1 from the sensor 10 and the marker 16 is within the angle of view 15 of the sensor 10. obtain a measurement result including the measured distance L1x to the marker 16 by . Then, the control unit 30 (determining unit 39) determines whether or not there is a disturbance within the angle of view 15 that causes a measurement error based on the measurement result and the distance L1. This makes it possible to determine the presence or absence of disturbance in three-dimensional distance measurement. Moreover, if there is a disturbance factor, it can be calibrated by actually measuring the distance to the marker 16 after removing it. Therefore, it is possible to perform disturbance determination processing and calibration in parallel.

Moreover, the presence or absence of complex disturbance factors can be determined at the same time, which is efficient. In addition, if there is a disturbance, the cause of the disturbance is notified, so that the user can easily remove the cause of the disturbance.

[Second embodiment]
Next, the configuration of the disturbance presence/absence determination apparatus 50 and the procedure for installing the sensor 10 according to the second embodiment of the present invention will be described. The basic configuration of the disturbance presence/absence determination device 50 is the same as that of the first embodiment. In this embodiment, the markers used are different from those in the first embodiment. Also, part of the determination method used in the setting of the marker in step S101 of FIG. 7 and the determination processing of the presence or absence of disturbance and its factor performed in step S203 is different from that of the first embodiment.

FIG. 8 is a schematic diagram of a marker body including a pair of markers 16A, 16B. In the first embodiment, one marker 16 was placed at a known distance L1 from sensor 10 . In contrast, in the present embodiment, a pair of markers 16A and 16B are arranged at arbitrary positions.

In the marker body, the markers 16A and 16B are integrally connected so that the distance L2 between the markers 16A and 16B is determined. The interval L2 is therefore known. Note that the markers 16A and 16B do not have to be integrated, and the user may place the markers 16A and 16B so as to maintain the interval L2 at the stage of placement.

In step S<b>101 , the user places markers 16</b>A and 16</b>B on floor 11 . At that time, the distance of the marker body from the sensor 10 does not matter. In addition, when the markers 16A and 16B have already been installed, the user may redo the installation. In step S102, the user adjusts the position and orientation of the sensor 10 so that the markers 16A and 16B are within the angle of view 15 (within the field of view) of the sensor 10. FIG.

In step S203, the CPU 31 executes determination processing of the presence or absence of disturbance and its factor based on the measurement result and the known interval L2. The measurement result here includes the three-dimensional distance from the sensor 10 to each of the markers 16A and 16B. From these three-dimensional distances, the CPU 31 calculates the measurement interval L2x between the markers 16A and 16B.

First, the CPU 31 determines whether or not the calculated measurement interval L2x matches the known interval L2. At that time, a threshold value for determination may be used, and the CPU 31 determines that the measurement interval L2x matches the interval L2 when “interval L2−predetermined value<measurement interval L2x<interval L2+predetermined value” holds. good too. This predetermined value is set to a value larger than the error of the measured distance L2x that can occur when there is no disturbance, and this value is stored in the ROM 32 in advance. Then, when the measurement interval L2x does not match the interval L2, the CPU 31 determines that there is disturbance due to multipath caused by reflections other than the markers 16A and 16B, short-distance high reflectors, or dust. .

Further, when the measurement interval L2x changes beyond the third threshold distance within the third predetermined time, the CPU 31 determines that there is disturbance due to dust. Further, when at least one of the distances to the two markers 16A and 16B changes beyond the fourth threshold distance within the fourth predetermined time, the CPU 31 determines that there is disturbance due to dust. Note that the fourth predetermined time and the fourth threshold distance may be the same values as the first predetermined time and the first threshold distance in the first embodiment, respectively.

If there is a position other than the markers 16A and 16B within the angle of view 15 where the light quantity exceeds the threshold light quantity on the brightness screen corresponding to the screen shown in FIG. 18 is determined to be a disturbance. Note that this threshold light amount may be the same value as the first threshold light amount in the first embodiment.

Further, the CPU 31 determines that there is disturbance due to the external light 19 when the light amount at the position corresponding to the external light 19 exceeds the threshold light amount on the luminance screen corresponding to the screen shown in FIG. Note that this threshold light amount may be the same value as the second threshold light amount in the first embodiment.

Note that by appropriately setting the threshold light amount, the CPU 31 can detect whether there is a position other than the markers 16A and 16B where the light amount exceeds the threshold light amount. It may be determined that there is a disturbance due to

Further, when the position of at least one of the markers 16A and 16B within the angle of view 15 changes beyond the fifth threshold distance within the fifth predetermined time, the CPU 31 determines that there is disturbance due to vibration. Note that the fifth predetermined time and the fifth threshold distance may be the same values as the second predetermined time and the second threshold distance in the first embodiment, respectively.

According to the present embodiment, the control unit 30 (acquisition unit 38) operates with the two markers 16A and 16B arranged at a known interval L2 and the markers 16A and 16B within the angle of view 15 of the sensor 10. , to the markers 16A and 16B by the sensor 10, including the respective distances. Then, the control unit 30 (determining unit 39) determines whether or not there is a disturbance within the angle of view 15 that causes a measurement error by the sensor 10, based on the measurement result and the interval L2. As a result, it is possible to obtain the same effect as in the first embodiment regarding the determination of the presence or absence of disturbance in three-dimensional distance measurement.

In addition, the same effects as in the first embodiment can be obtained in terms of parallel execution of disturbance determination processing and calibration, ability to simultaneously determine the presence or absence of complex disturbance factors, and notification of disturbance factors. be able to.

Note that, in the present embodiment as well, among multiple paths, a high reflector at a short distance, external light, dust, and vibration, a plurality of possible combinations may be used as detection targets. In addition, it is not necessary to specify only one disturbance factor, and it is useful to be able to specify any one of two or more disturbance factors.

<Modification>
The above-described embodiment is merely an example of the configuration of the present invention. The present invention is not limited to the specific forms described above, and various modifications are possible within the technical scope of the present invention.

Note that it is not essential for the control unit 30 to have the notification unit 40 if the effect of notifying the presence or absence of disturbance and the cause thereof is not desired.

From the standpoint of obtaining the effect of determining the presence or absence of disturbance in three-dimensional distance measurement, the three-dimensional distance sensor to be used may be any other type of sensor as long as it outputs three-dimensional distance information. may When a TOF sensor is employed, it may be either of a direct type (direct type) or an indirect type (indirect type). In particular, when determining the presence or absence of disturbance factors such as dust or vibration, it is not essential that the three-dimensional distance sensor output light amount information. Further, depending on the disturbance factor to be determined, a sensor using other than light, such as radio waves, can also be applied.

Note that even if an OK instruction is input in step S206, the process shown in FIG. 7 may be returned to step S201 and the processes of steps S201 to S206 may be repeated without ending the process. In other words, the presence or absence of disturbance may be continuously determined. For example, if the determination of the presence or absence of disturbance is continued while the danger source 13 is in operation, even if the disturbance suddenly occurs, it can be detected and notified immediately.

As another method different from the first and second embodiments, two sensors having different angles of view may be used for disturbance determination. For example, on the condition that the marker is placed in the angle of view, after obtaining the measurement result with the sensor 10, the second sensor with a narrower angle of view than the sensor 10 is used to obtain the measurement result. Then, if the measured distances to the marker indicated by both measurement results are significantly different, it may be determined that there is some disturbance factor. For example, if the target disturbance factor is multipath, a short-distance high reflector, or external light, it is possible to realize a disturbance presence/absence determination device that has a simple configuration and is highly effective.

The disturbance presence/absence determination device 50 can be configured by, for example, a computer including a processor, memory, storage, and the like. In that case, the configuration shown in FIG. 5 is realized by loading the program stored in the storage into the memory and executing the program by the processor. Such a computer may be a general-purpose computer such as a personal computer, a server computer, a tablet terminal, a smart phone, or a built-in computer such as an on-board computer. Alternatively, all or part of the configuration shown in FIG. 5 may be configured with an ASIC, FPGA, or the like. Alternatively, all or part of the configuration shown in FIG. 5 may be realized by cloud computing or distributed computing.

<Appendix>
[1] A marker (16) is placed at a known distance (L1) from the three-dimensional distance sensor, and the marker is within the angle of view of the three-dimensional distance sensor. obtaining means (38) for obtaining a measurement result including the distance (L1x) of
determining means (39) for determining whether or not there is a disturbance that causes measurement error by the three-dimensional distance sensor, based on the measurement result obtained by the obtaining means and the known distance; A disturbance presence/absence determination device (50) characterized by:

[2] Two markers are arranged at a known interval (L2), and each distance to the two markers by the three-dimensional distance sensor in a state in which the two markers are within the angle of view of the three-dimensional distance sensor obtaining means (38) for obtaining a measurement result comprising
determining means (39) for determining whether or not there is a disturbance that causes measurement error by the three-dimensional distance sensor, based on the measurement result obtained by the obtaining means and the known distance. A disturbance presence/absence determination device (50) characterized by:

[3] A measurement result including the distance to the marker by the three-dimensional distance sensor in a state where the marker is placed at a known distance from the three-dimensional distance sensor and the marker is within the angle of view of the three-dimensional distance sensor. an acquisition step (S202) for acquiring
a determination step (S203) for determining whether or not there is a disturbance that causes a measurement error by the three-dimensional distance sensor, based on the measurement result obtained by the obtaining step and the known distance;
A disturbance presence/absence determination method comprising:

[4] Measurement including each distance to the two markers by the three-dimensional distance sensor in a state in which the two markers are arranged at a known interval and the two markers are within the angle of view of the three-dimensional distance sensor. an obtaining step (S202) of obtaining a result;
a determination step (S203) of determining whether or not there is a disturbance that causes a measurement error by the three-dimensional distance sensor, based on the measurement result obtained in the obtaining step and the known distance;
A disturbance presence/absence determination method comprising:

10: Sensors 16, 16A, 16B: Marker 38: Acquisition unit 39: Determination unit 40: Notification unit 50: Disturbance presence/absence determination device L1: Distance L1x: Measured distance

Claims (17)

A measurement result including the distance to the marker by the three-dimensional distance sensor is acquired in a state where the marker is placed at a known distance from the three-dimensional distance sensor and the marker is within the angle of view of the three-dimensional distance sensor. acquisition means;
determination means for determining whether or not there is a disturbance that causes a measurement error by the three-dimensional distance sensor, based on the measurement result acquired by the acquisition means and the known distance;
A disturbance presence/absence determination device comprising: The three-dimensional distance sensor is a sensor that obtains distance information to the measurement target based on light reflected by the measurement target,
The determining means is characterized in that, when the measurement result indicates that the distance to the marker is longer than the known distance, it is determined that there is disturbance due to multipath caused by reflection outside the object to be measured. The disturbance presence/absence determination device according to claim 1 . The three-dimensional distance sensor is a sensor that obtains distance information to the measurement target based on light reflected by the measurement target,
The measurement result includes light amount information at each position within the angle of view,
The determination means determines that the measurement result indicates that the distance to the marker is shorter than the known distance, and that there is a position other than the marker within the angle of view where the light intensity exceeds a first threshold light intensity. 3. The disturbance presence/absence determination device according to claim 1, wherein it is determined that there is a disturbance due to a high reflector at a short distance in the case of . The measurement result includes light amount information at each position within the angle of view,
2. The judging means judges that there is disturbance due to external light when there is a position other than the marker within the angle of view where the light quantity exceeds a second threshold light quantity. 2. The disturbance presence/absence determination device according to 2. 3. The determination means determines that there is disturbance due to dust when the distance to the marker indicated by the measurement result changes by exceeding a first threshold distance within a first predetermined time. The disturbance presence/absence determination device according to any one of 1 to 4. The determination means determines that there is disturbance due to vibration when the position of the marker within the angle of view indicated by the measurement result changes by exceeding a second threshold distance within a second predetermined time. A disturbance presence/absence determination device according to any one of claims 1 to 5. Acquiring measurement results including distances to the two markers by the three-dimensional distance sensor in a state in which two markers are arranged at a known interval and the two markers are within the angle of view of the three-dimensional distance sensor. a obtaining means for
determination means for determining whether or not there is a disturbance that causes a measurement error by the three-dimensional distance sensor, based on the measurement result acquired by the acquisition means and the known distance;
A disturbance presence/absence determination device comprising: The three-dimensional distance sensor is a sensor that obtains distance information to the measurement target based on light reflected by the measurement target,
The determination means calculates the distance between the two markers based on the distances to the two markers acquired by the acquisition means, and the calculated distance between the two markers matches the known distance. 8. The apparatus for determining the presence or absence of disturbance according to claim 7, wherein if not, it is determined that there is disturbance due to any one of multipath caused by reflection from objects other than the object to be measured, a high reflector at a short distance, or dust. . The determining means calculates an interval between the two markers based on the respective distances to the two markers acquired by the acquiring means, and the calculated interval between the two markers is within a third predetermined time. 8. The disturbance presence/absence determination device according to claim 7, wherein when the distance changes to exceed a third threshold distance, it is determined that there is disturbance due to dust. The determination means determines that there is disturbance due to dust when at least one of the distances to the two markers acquired by the acquisition means changes by exceeding a fourth threshold distance within a fourth predetermined time. 8. The disturbance presence/absence determination device according to claim 7, wherein the determination is made. The three-dimensional distance sensor is a sensor that obtains distance information to the measurement target based on light reflected by the measurement target,
The measurement result includes light amount information at each position within the angle of view,
If there is a position other than the two markers within the angle of view where the amount of light exceeds the threshold amount of light, the determination means determines that there is disturbance due to either a short-distance high reflector or external light. 11. The disturbance presence/absence determination device according to any one of claims 7 to 10, characterized in that determination is made. When the position of at least one of the two markers indicated by the measurement result within the angle of view changes by exceeding a fifth threshold distance within a fifth predetermined time, the determination means determines that there is disturbance due to vibration. The disturbance presence/absence determination device according to any one of claims 7 to 11, characterized in that it determines that Claims 1 to 1, characterized in that it has an informing means for informing a result of judgment by said judging means.
13. The disturbance presence/absence determination device according to any one of 12. The disturbance presence/absence determination device according to any one of claims 1 to 13, wherein the three-dimensional distance sensor is a TOF sensor. A measurement result including the distance to the marker by the three-dimensional distance sensor is acquired in a state where the marker is placed at a known distance from the three-dimensional distance sensor and the marker is within the angle of view of the three-dimensional distance sensor. an acquisition step;
and a determination step of determining whether or not there is a disturbance that causes a measurement error by the three-dimensional distance sensor, based on the measurement result obtained by the obtaining step and the known distance. Disturbance presence/absence judgment method. Acquiring measurement results including distances to the two markers by the three-dimensional distance sensor in a state in which two markers are arranged at a known interval and the two markers are within the angle of view of the three-dimensional distance sensor. a obtaining step for
and a determination step of determining whether or not there is a disturbance that causes a measurement error by the three-dimensional distance sensor based on the measurement result obtained by the obtaining step and the known distance. Disturbance presence/absence judgment method. A program for causing a computer to execute each step of the disturbance presence/absence determination method according to claim 15 or 16.

Images