Attached matter detection device

Abstract

To provide one example of an attached matter detection device which can cope with a case where it is difficult to repeatedly measure the same measurement position.SOLUTION: An attached matter detection device 10 can cope with a case where it is difficult to repeatedly measure the same measurement position by calculating a lamination size of the attached matter in an area coordinate value Uc replaced by a coordinate replacement function using at least two Y values corresponding to the area coordinate value Uc. The coordinate replacement function is a grouping function that replaces a position coordinate value Pc included in a unit area Ua among position coordinate values Pc acquired by an acquisition function with the area coordinate value Uc.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to an object detection device that detects an object attached to a surface of an object. [Background technology]

[0002] For example, in the invention described in Patent Document 1, obstacles are detected by a distance measuring sensor such as a LiDAR sensor. A 3D-LiDAR sensor that uses this LiDAR sensor is capable of three-dimensional measurements by repeating the process of shining laser light at an object and measuring the distance to the point where it is hit (hereinafter also referred to as the measurement position) based on the time difference and phase difference of the laser light as it is reflected, scattered, and returned, while gradually changing the light irradiation angle and measurement position (hereinafter this action is referred to as "scanning"). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-139304 A Summary of the Invention [Problem to be solved by the invention]

[0004] When performing 3D measurement by repeating scanning, ideally it is desirable to repeatedly measure the same measurement position. The reason for performing 3D measurement by repeating scanning is that there is a possibility that accurate measurement cannot be performed in a single measurement due to the influence of disturbances, etc.

[0005] However, for example, when an object detection device is attached to a railway vehicle and measures a part of the railway vehicle, the light-emitting unit, the light-receiving unit, and / or the target vibrates, causing the relative positional relationship between the light-emitting unit, the light-receiving unit, and the target to fluctuate. Therefore, in this case, it is practically impossible to repeatedly measure the same measurement position.

[0006] In view of the above, the present disclosure discloses an example of an object detection device that can handle cases where it is difficult to repeatedly measure the same measurement position. [Means for solving the problem]

[0007] An object detection device that includes a light-emitting unit (11) and a light-receiving unit (12) and detects objects attached to a surface by irradiating a pulsed laser light from the light-emitting unit (11) toward the object and performing three-dimensional measurement of the surface side of the object, desirably includes at least one of the following components:

[0008] That is, the components include an acquisition unit that acquires three coordinate values ​​(X, Y, Z) at multiple measurement positions (Mp) by scanning a laser beam within a measurement range (Mta) and irradiating it toward the target object, and a calculation unit (13) that operates the acquisition unit at least twice and calculates the layered dimensions of the adhesion material using the acquired coordinate values ​​(X, Y, Z).

[0009] It is desirable that the calculation unit (13) is capable of performing a coordinate substitution function of replacing the position coordinate values ​​(Pc) included in the unit area (Ua) among the position coordinate values ​​(Pc) acquired by the acquisition unit with area coordinate values ​​(Uc), and a calculation function of calculating the layering dimension of the adhesion at the area coordinate value (Uc) by utilizing at least two Y values ​​corresponding to the area coordinate value (Uc) replaced by the coordinate substitution function among the multiple Y values ​​acquired by the acquisition unit.

[0010] The position where the laser light is irradiated is defined as the measurement position (Mp), and the coordinate values ​​of the mutually orthogonal X-, Y-, and Z-directions at the measurement position (Mp) are defined as the X-, Y-, and Z-values, respectively. The Y-direction is defined as the direction from the light-emitting unit (11) toward the target object. The measurement position (Mp) is specified by the X- and Z-values, and the X- and Z-values ​​indicating the measurement position (Mp) are defined as position coordinate values ​​(Pc).

[0011] Furthermore, the calculation unit (13) can recognize the measurement target range (Mta) as a collection of multiple unit areas (Ua), and the coordinate values ​​(X, Y, Z) for each unit area (Ua) in the measurement target range (Mta) are defined as area coordinate values ​​(Uc).

[0012] As a result, the adhesion detection device uses at least two Y values ​​corresponding to the area coordinate value (Uc) replaced by the coordinate replacement function to calculate the layer dimension of the adhesion at the area coordinate value (Uc), making it possible to handle cases where it is difficult to repeatedly measure the same measurement position.

[0013] Incidentally, the symbols in the above parentheses are examples showing the corresponding relationship with the specific configurations etc. described in the embodiments described below, and the present disclosure is not limited to the specific configurations etc. shown by the symbols in the above parentheses. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1A is a diagram showing a railway vehicle, and FIG. 1B is an enlarged view of part A in FIG. 1A. [Diagram 2] 1A and 1B are diagrams showing the arrangement of a sensor unit and a blocking plate (measurement object). [Diagram 3] FIG. 1 is a conceptual diagram of a measurement position. [Figure 4] FIG. 13 is a conceptual diagram of a coordinate replacement function. [Diagram 5] A and B are diagrams in which coordinate values ​​are plotted in XYZ space. [Figure 6] A to C are conceptual diagrams of the calculation function. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The following "embodiment of the invention" shows an example of an embodiment that falls within the technical scope of the present disclosure. In other words, the invention-specific matters described in the claims are not limited to the specific configurations and structures shown in the following embodiment.

[0016] (First embodiment) <1. Overview of the adhesion detection device> In this embodiment, an example of an object detection device according to the present disclosure is applied to an object detection device that detects objects (for example, snow height) attached to a railway vehicle (hereinafter referred to as a vehicle).

[0017] 1A and 1B, the object-detecting device 10 detects the height of snow that has accumulated on a blocking plate 1 provided near the wheels of a vehicle. The blocking plate 1 is a cover that covers an electric device disposed near the wheels.

[0018] The object-detecting device 10 is configured to include a light-emitting unit 11, a light-receiving unit 12, and a control device 13. The light-emitting unit 11 irradiates a pulsed laser light toward a surface of a measurement object (a blocking plate 1 in this embodiment) while scanning the surface. The light-receiving unit 12 detects the reflected laser light.

[0019] In this embodiment, a film-like heater (not shown) that covers the light-emitting portion 11 and the light-receiving portion 12, and a hydrophilic transparent film-like cover (not shown) that covers the heater are provided.

[0020] In this embodiment, a sensor unit 14 having a light emitting unit 11 (including a function of scanning laser light) and a light receiving unit 12 is configured by a 3D-LiDAR sensor using a LiDAR sensor. A portion of the sensor unit 14 facing the blocking plate 1 is covered with a heater and a cover.

[0021] The control device 13 controls the operation of the sensor unit 14 and calculates the amount of adhesion on the surface side of the blocking plate 1, i.e., the snow accumulation height, using the information obtained via the sensor unit 14. The control device 13 is composed of a computer having a CPU, ROM, RAM, a non-volatile memory unit, etc.

[0022] Software for controlling the operation of the sensor unit 14 and software for calculating (computing) the snow height, i.e., the measured distance, using the information obtained via the sensor unit 14 are pre-stored in a ROM or non-volatile memory unit.

[0023] <2. Snow height calculation method> <2.1 Overview of calculation method> The object detection device 10 irradiates a pulsed laser light toward the blocking plate 1, and measures the distance to the measurement position Mp by gradually changing the position where the laser light is irradiated (hereinafter referred to as the measurement position Mp) (this action is referred to as "scanning") based on the time difference and phase difference of the laser light as it is reflected, scattered, and returned.

[0024] The "distance to the measurement position Mp (hereinafter referred to as the measurement distance)" refers to the distance from a predetermined position (e.g., the sensor unit 14) to the measurement position Mp. In other words, as the snow accumulation height (hereinafter referred to as the stacking dimension) on the closing plate 1 increases, the measurement distance decreases.

[0025] For this reason, the non-volatile memory unit of the control device 13 pre-stores the measured distance (hereinafter referred to as the reference distance) when the stack dimension is 0, that is, when no snow or the like is attached to the blocking plate 1, in association with the measurement position Mp.

[0026] Then, the control device 13 calculates the stacking dimension by subtracting the reference distance from the measured distance for each measurement position Mp. In this embodiment, the angle between the laser light and the closing plate 1 is not 90 degrees (see FIG. 2A).

[0027] Therefore, the control device 13 according to the present embodiment calculates the stacking dimension by correcting the measured distance using a known method such as coordinate conversion (see FIG. 2B). Note that the "correction of the measured distance (coordinate conversion)" may be performed in any step of the steps of calculating the stacking dimension.

[0028] Incidentally, the "correction of the measured distance (coordinate conversion)" is not an essential calculation for calculating the stacking dimension. In other words, when the angle between the laser light and the blocking plate 1 is 90 degrees, the correction (coordinate conversion) is not necessary.

[0029] In the following description, in order to facilitate understanding of the method of calculating the measurement distance, the angle between the laser light and the blocking plate 1 is set to 90 degrees. In other words, the following description omits the description of the correction (coordinate conversion).

[0030] <2.2 Overview of the measurement distance calculation method> <Definitions of terms, etc.> The "measurement position Mp" refers to the position irradiated with the laser light (for example, the position of the black circle in FIG. 3).

[0031] The "X value, Y value, and Z value" refer to the coordinate values ​​in the mutually orthogonal X direction, Y direction, and Z direction at the measurement position Mp. The origin of the coordinates is arbitrary (for example, the lower corner of the closing plate 1, etc.).

[0032] The "Y direction" refers to the direction from the sensor unit 14 toward the target object (see FIG. 2B). Therefore, in this embodiment, the measurement position Mp is specified by the X value and the Z value. Hereinafter, the X value and the Z value indicating the measurement position Mp will be referred to as the "position coordinate value Pc."

[0033] In other words, when the measurement position Mp is projected onto a virtual plane perpendicular to the Y direction, the position coordinate value Pc is a coordinate value indicating the position of the projected measurement position Mp on the virtual plane. Therefore, the Y value at a specific measurement position Mp is a value proportional to the layer dimension at the specific measurement position Mp.

[0034] The control device 13 can recognize the "measurement target range Mta (in this embodiment, the surface of the blocking plate 1)" as a collection of multiple "unit areas Ua." The unit area Ua is, for example, a rectangular area that is defined in advance by a unit length Ux (e.g., 10 mm) in the X direction and a unit length Uz (e.g., 10 mm) in the Z direction.

[0035] That is, as shown in FIG. 3, the control device 13 divides the surface of the closing plate 1 into a grid in the X and Z directions, and recognizes the measurement target range Mta as a collection of squares (=unit areas Ua) constituting the grid.

[0036] Therefore, each square that constitutes the grid corresponds to a unit area Ua. The coordinate values ​​X, Y, and Z for each unit area Ua are called "area coordinate values ​​Uc." In other words, the area coordinate values ​​Uc are vectors whose components are the "position coordinate value Pc of the unit area Ua" and the "Y value for the position coordinate value Pc."

[0037] <Function for measuring distance calculation by the control device> The control device 13 executes at least an "acquisition function," a "coordinate value conversion function," and a "calculation function" in order to calculate (compute) the measurement distance.

[0038] <Acquisition function> The acquisition function is a function for acquiring three coordinate values ​​X, Y, and Z at a plurality of measurement positions Mp by scanning the laser light within the measurement target range Mta and irradiating it toward the blocking plate 1. At this time, the control device 13 operates the acquisition function at least twice and executes a calculation function etc. using the acquired coordinate values ​​X, Y, and Z.

[0039] <Coordinate replacement function> The coordinate replacement function is a grouping function that replaces the position coordinate values ​​Pc included in the unit area Ua, among the position coordinate values ​​Pc acquired by the acquisition function, with area coordinate values ​​Uc (see FIG. 4).

[0040] Specifically, the coordinate substitution function replaces the position coordinate value Pc acquired by the acquisition function with the area coordinate value Uc by truncating the acquired X value by unit length Ux in the X direction and truncating the acquired Z value by unit length Uz in the Z direction.

[0041] Therefore, the components corresponding to the area coordinate value Uc and the position coordinate value Pc, that is, the X value and the Z value, are values ​​in increments of unit length (for example, 10 mm). Note that the Y value is the value acquired by the acquisition function as is.

[0042] Therefore, after the coordinate replacement function is executed, two or more Y values ​​can exist for the same position coordinate value Pc. That is, the position coordinate value Pc acquired by the acquisition function is plotted in the XYZ space as shown in Fig. 5A. Note that the gray circles in Fig. 5A indicate the plotted position coordinate values ​​Pc.

[0043] After the coordinate replacement function is executed, the position coordinate values ​​Pc included in the unit area Ua among the acquired position coordinate values ​​Pc are replaced with area coordinate values ​​Uc, as shown in Fig. 5B. Note that the gray circles in Fig. 5B indicate the replaced area coordinate values ​​Uc.

[0044] <Calculation function> The calculation function is a function that uses at least two (in this embodiment, all) Y values ​​among the multiple Y values ​​acquired by the acquisition function that correspond to the area coordinate value Uc replaced by the coordinate substitution function to calculate the layering dimension of the adhesion (in this example, the measured distance) at the area coordinate value Uc.

[0045] For example, when the acquisition function is executed four times, four Y values ​​exist for each position coordinate value Pc after the coordinate replacement function is executed, as shown in Fig. 5B. In this embodiment, the four Y values ​​are used to determine the measured distance for each area coordinate value Uc, that is, the representative value Tv representing each position coordinate value Pc.

[0046] Specifically, the calculation function is realized by executing at least a "variation judgment function," an "exclusion function," a "representative value determination function," and an "interpolation function." <Variation judgment function> The variation determination function is a function that determines, for each of a plurality of area coordinate values ​​Uc, whether or not the variation in a plurality of Y values ​​corresponding to that area coordinate value Uc is equal to or greater than a predetermined threshold value.

[0047] In addition, the control device 13 in this embodiment calculates the standard deviation value of multiple Y values ​​corresponding to the area coordinate value Uc, i.e., the multiple Y values ​​existing in the position coordinate value Pc, and if the calculated standard deviation value is equal to or greater than a predetermined threshold value (for example, 5), it is deemed to have a large variation (abnormal value).

[0048] <Exclusion function> The exclusion function is a function for excluding area coordinate values ​​Uc where the variation in multiple Y values ​​is equal to or greater than a threshold value due to the variation determination function from the calculation target of the stacking dimension (measured distance in this example). In other words, for area coordinate values ​​Uc where there is a Y value with large variation, that is, a Y value that can be considered as "abnormal", the control device 13 does not execute the calculation of the measured distance using the acquired coordinate values ​​(X value, Y value, Z value).

[0049] <Representative value determination function> The representative value determination function is a function that determines a representative value Tv representing multiple Y values ​​corresponding to each of the multiple area coordinate values ​​Uc (hereinafter referred to as valid coordinate values ​​Vc) other than the area coordinate values ​​Uc excluded by the exclusion function (hereinafter referred to as excluded coordinate values ​​Ec).

[0050] Specifically, the representative value determination function rounds the acquired multiple Y values ​​by unit length Uy in the Y direction, and determines the representative value Tv using the most frequent value among the multiple rounded Y values. For example, the control device 13 according to this embodiment classifies the acquired multiple Y values ​​into intervals of 0 mm to 10 mm, 10 mm to 20 mm, and 20 mm to 30 mm, and sets the average value of the multiple Y values ​​belonging to the interval to which the majority of the Y values ​​belong as the representative value Tv.

[0051] <Interpolation function> The representative value determination function is a function for determining a representative value Tv of the valid coordinate value Vc, whereas the interpolation function is a function for determining a representative value Tv of the excluded coordinate value Ec. Specifically, the control device 13 determines the representative value Tv of the excluded coordinate value Ec using a plurality of surrounding values ​​Sv. The surrounding values ​​Sv refer to the representative values ​​Tv of each of the surrounding coordinate values ​​Sc. The surrounding coordinate values ​​Sc refer to two or more area coordinate values ​​Uc surrounding the excluded coordinate value Ec.

[0052] That is, the control device 13 determines the average value of the surrounding values ​​Sv of the excluded coordinate value Ec as the representative value Tv of the excluded coordinate value Ec as shown in Figures 6B and 6C. That is, the control device 13 first excludes area coordinate values ​​Uc having Y values ​​with large variations from the targets for which the representative value determination function is executed (see Figures 6A and 6B).

[0053] Next, the control device 13 determines the representative value Tv of the valid coordinate values ​​Vc, and then determines the average value of the surrounding values ​​Sv of the excluded coordinate values ​​Ec as the representative value Tv of the excluded coordinate values ​​Ec. This allows the control device 13 to grasp the representative values ​​Tv for all area coordinate values ​​Uc, that is, the measured distances for all area coordinate values ​​Uc.

[0054] Therefore, the control device 13 determines the stacking dimension for each area coordinate value Uc by subtracting the reference distance from the measured distance for each area coordinate value Uc. In other words, the object-detecting device 10 can measure the front surface side of the closing plate 1 in three dimensions.

[0055] 3. Features of the object-sensing device according to the present embodiment In the adhesion detection device 10 of this embodiment, the stacking dimension of the adhesion at the area coordinate value Uc is calculated using at least two Y values ​​corresponding to the area coordinate value Uc replaced by the coordinate replacement function, making it possible to respond to cases where it is difficult to repeatedly measure the same measurement position.

[0056] Furthermore, in the object detection device 10, the variation judgment function excludes the area coordinate value Uc where the variation in the multiple Y values ​​is equal to or greater than a threshold value from the calculation target of the stacking dimension. This makes it possible to reduce the influence of disturbance obstacles that are an obstacle to the laser light (e.g., snow particles) even in a situation where they irregularly move in and out between the sensor unit 14 and the blocking plate 1 and cause abnormal values.

[0057] Furthermore, the adhesion detection device 10 can improve measurement accuracy by repeatedly measuring the same measurement position while reducing the effects of disturbance obstacles, making it possible to obtain true stacking dimensions with a small computational load.

[0058] In addition, since a commercially available 3D-LiDAR sensor can be used as the sensor unit 14, snow accretion can be quantitatively and in real time evaluated with a simple and lightweight sensor unit. In addition, the data can be shared with central command and other vehicles to ensure stable transportation, and secondary effects such as elucidating the snow accretion growth mechanism and optimizing speed regulations can be expected.

[0059] Furthermore, a film-like heater that covers the light-emitting unit 11 and the light-receiving unit 12, and a hydrophilic transparent film-like cover that covers the heater are provided. This prevents snow from adhering to the light-emitting unit 11 and the light-receiving unit 12, and prevents water from remaining on the light-emitting unit 11 and the light-receiving unit 12. If water remains on the light-emitting unit 11 and the light-receiving unit 12, it refracts the laser light, making it difficult to measure an accurate distance.

[0060] (Other embodiments) In the variation determination function according to the embodiment described above, the standard deviation value is used for the determination. However, the present disclosure is not limited to this. That is, the present disclosure may determine the variation based on, for example, only the deviation.

[0061] The coordinate replacement function according to the above embodiment rounds down in units of length. However, the present disclosure is not limited to this. That is, the present disclosure may replace coordinates by rounding up or down the unit length, for example.

[0062] In the above embodiment, the area coordinate value Uc where the variation of the multiple Y values ​​is equal to or greater than a threshold value is excluded from the calculation of the stacking dimension. However, the present disclosure is not limited to this. That is, the present disclosure may, for example, exclude only the Y values ​​with large deviations, and determine the representative value Tv using the Y values ​​that are not excluded, without interpolation.

[0063] In the above embodiment, the representative value Tv of the excluded coordinate value Ec is determined using the surrounding value Sv. However, the present disclosure is not limited to this. That is, the present disclosure may determine the representative value Tv of the excluded coordinate value Ec using, for example, a known interpolation formula.

[0064] In the representative value determination function according to the embodiment described above, the average value of a plurality of Y values ​​belonging to the section to which the most Y values ​​belong is set as the representative value Tv. However, the present disclosure is not limited to this. That is, in the present disclosure, for example, the maximum value or the median value of a plurality of Y values ​​may be set as the representative value Tv.

[0065] In the above embodiment, the object detection device according to the present disclosure is applied to a railway vehicle. However, the present disclosure is not limited thereto. That is, the present disclosure may be applied to measurement of objects other than the amount of snow sitting on the vehicle, or to applications other than railway vehicles.

[0066] In the above-described embodiment, a film-like heater that covers the light-emitting unit 11 and the light-receiving unit 12, and a hydrophilic transparent film-like cover that covers the heater are provided. However, the present disclosure is not limited to this. In other words, the present disclosure may be configured such that the heater or the cover is eliminated.

[0067] Furthermore, the present disclosure is not limited to the above-mentioned embodiments as long as it is consistent with the gist of the disclosure described in the above-mentioned embodiments. Therefore, the present disclosure may be a configuration in which at least two of the above-mentioned embodiments are combined, or a configuration in which any of the components illustrated or the components described with reference numerals in the above-mentioned embodiments are eliminated. [Explanation of symbols]

[0068] 10... Adhesion detection device 11… Light emitting part 12... Light receiving section 13...Control device 14... Sensor section

Claims

1. An object detection device includes a light-emitting unit and a light-receiving unit, and detects an object adhering to a surface by irradiating a pulsed laser beam from the light-emitting unit toward the object and performing three-dimensional measurement of a surface side of the object, the device comprising: The position where the laser light is irradiated is defined as a measurement position, The coordinate values ​​of the measurement position in an X direction, a Y direction, and a Z direction perpendicular to each other are defined as an X value, a Y value, and a Z value, respectively. The Y direction is a direction from the light emitting unit toward the target object, When the measurement position is specified by an X value and a Z value, and the X value and the Z value indicating the measurement position are set as position coordinate values, an acquisition unit that acquires the three coordinate values ​​at a plurality of measurement positions by irradiating the laser light onto an object while scanning the object within a measurement range; a calculation unit that operates the acquisition unit at least twice and calculates a layered dimension of the deposit using the acquired coordinate values, The calculation unit is capable of recognizing the measurement target range as a collection of a plurality of unit areas, and when coordinate values ​​relating to each unit area in the measurement target range are taken as area coordinate values, The calculation unit is a coordinate replacement function of replacing position coordinate values ​​included in the unit area among the position coordinate values ​​acquired by the acquisition unit with the area coordinate values; and A calculation function of calculating a layered dimension of the deposit at the area coordinate value by using at least two Y values ​​corresponding to the area coordinate value replaced by the coordinate replacement function among the multiple Y values ​​acquired by the acquisition unit. The object-detecting device is capable of achieving the above.

2. The unit area is an area that is defined by a unit length in advance in the X direction and a unit length in advance in the Z direction, The coordinate substitution function is The obtained X value is truncated to a unit length unit in the X direction, and The obtained Z value is rounded down to the unit length in the Z direction. The position coordinate value acquired by the acquisition unit is replaced with the area coordinate value. The object-detecting device according to claim 1 .

3. The calculation function is a variation determination function for determining whether or not a variation in a plurality of Y values ​​corresponding to each of the plurality of area coordinate values ​​is equal to or greater than a predetermined threshold value; An exclusion function that excludes area coordinate values ​​in which the variation in a plurality of Y values ​​is equal to or greater than the threshold value by the variation determination function from the calculation target of the stacking dimension; A representative value determination function that determines a representative value representing a plurality of Y values ​​corresponding to each of the plurality of area coordinate values ​​other than the area coordinate values ​​excluded by the exclusion function among the plurality of area coordinate values. The object-detecting device according to claim 1 , further comprising:

4. When the area coordinate value excluded by the exclusion function is defined as an excluded coordinate value, two or more area coordinate values ​​around the excluded coordinate value are defined as surrounding coordinate values, and a representative value of each of the surrounding coordinate values ​​is defined as a surrounding value, The object detection device according to claim 3 , wherein the calculation function determines a representative value of the excluded coordinate values ​​by using a plurality of the surrounding values.

5. The representative value determination function is The acquired multiple Y values ​​are rounded to a unit length unit in the Y direction; The representative value is determined by using the most frequent value among the plurality of rounded Y values. The object-detecting device according to claim 3 .

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