JP2012237592A - Laser radar device and laser radar method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional laser radar device and a method capable of reliably detecting a detection object regardless of a position of a sea surface.SOLUTION: A laser radar method detects a detection object by excluding point data, included in a continuous point data group with height distances equal to or lower than an elimination threshold value which is set with an expected maximum wave height generated on the sea as an upper limit, from the continuous point data group consisting of a plurality of point data continuously arranged in a vertical direction.

Description

  The present invention relates to a laser radar device and a laser radar method.

For example, as shown in Patent Document 1, a three-dimensional laser radar device is used to detect a marine vessel.
This three-dimensional laser radar device detects a marine vessel from the distribution of point data obtained by projecting a measurement laser beam while scanning the measurement space and receiving the return light of the measurement laser beam. .
More specifically, the three-dimensional laser radar device detects the presence or absence of an object to be detected based on whether or not the return light of the measurement laser light is received, and receives the return light after emitting the measurement laser light. The distance to the detected object is measured from the time until the detection, and the direction of the detected object is measured from the emission angle of the measurement laser beam.

In such a three-dimensional laser radar device, return light generated by reflection of the measurement laser light in a region other than the detection target and return light generated by reflection of the measurement laser light from the detection target such as a ship. Cannot be identified.
On the other hand, the measurement laser light may be reflected by a part of a wave such as a white wave generated when the wave rises or the wave breaks down.
For this reason, the three-dimensional laser radar device cannot identify the return light generated by the measurement laser beam reflected by a part of the wave, and may erroneously detect a part of the wave as a ship. is there.

  Such false detection can be prevented by masking the area below the sea level so that it does not exist. For this reason, in the three-dimensional laser radar device, a reference plane set based on the sea level is stored in advance, and a part of the wave is erroneously detected as a ship by ignoring point data below the reference plane. It is possible to prevent this.

However, except for the case where the light is reflected by a part of the wave as described above, the measurement laser light is basically totally reflected on the sea surface, so that no return light reaching the three-dimensional laser radar device is generated on the sea surface. For this reason, the three-dimensional laser radar apparatus cannot measure the sea level position. On the other hand, as is well known, sea level always fluctuates due to tides.
For this reason, Patent Document 1 proposes a method of constantly correcting the above-described reference plane by calculating a tide level using a GPS, a radio clock, a gyrocompass, or the like.

JP 2008-281380 A

However, in order to calculate the tide level, it becomes necessary to mount devices such as a GPS, a radio timepiece, and a gyrocompass in the three-dimensional laser radar device as described above, which leads to complication of the three-dimensional laser radar device. .
That is, in such a three-dimensional laser radar device, the tide level cannot be accurately calculated unless each of the GPS, the radio-controlled timepiece, and the gyrocompass is operating normally, so that the reliability of the device is lowered.

Further, the sea level position calculated using GPS, a radio clock, a gyro compass, or the like is not the sea level position with respect to the three-dimensional laser radar, but the sea level position (tide level) with respect to the land. For this reason, a three-dimensional laser radar device equipped with devices such as a radio timepiece and a gyrocompass needs to be fixed to the land.
If the three-dimensional laser radar device is mounted on a moving body such as a ship, it is difficult to accurately calculate the sea surface position, making it difficult to perform masking accurately, and other ships may not be detected. There is.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to make it possible to reliably detect a detection target regardless of the sea surface position in a three-dimensional laser radar apparatus and method.

  The present invention adopts the following configuration as means for solving the above-described problems.

  According to a first aspect of the present invention, a measurement laser beam is projected while scanning a measurement space, and a point data distribution obtained by receiving a return light of the measurement laser beam with a light receiver is used to detect a detection object at sea. A laser radar device that performs detection, the height distance of a continuous point data group consisting of a plurality of the above-mentioned point data arranged continuously in the vertical direction is set with an assumed maximum value of a wave generated on the sea as an upper limit. A configuration is adopted in which signal processing means for detecting the detection target object by excluding the point data included in the continuous point data group equal to or less than the exclusion threshold is adopted.

  According to a second aspect of the present invention, in the first aspect of the present invention, a configuration is provided in which scanning means for scanning the measurement laser beam with a vertical movement speed higher than a horizontal movement speed is provided.

  According to a third aspect, in the second aspect, the scanning unit includes a polygon scanner that scans the measurement laser beam in a vertical direction and a galvano scanner that scans the measurement laser beam in a horizontal direction. Adopt the configuration.

  According to a fourth aspect of the present invention, the measurement laser beam is projected while scanning the measurement space, and the distribution of the point data obtained by receiving the return light of the measurement laser beam with a light receiver is used to detect the detection object at sea. This is a laser radar method that performs detection, and among the continuous point data group consisting of a plurality of the above-mentioned point data arranged continuously in the vertical direction, the height distance is set with the assumed maximum value of waves generated on the sea as the upper limit. The detection object is detected by excluding the point data included in the continuous point data group equal to or less than the exclusion threshold.

In the three-dimensional laser radar device, the detection target is detected by receiving the return light generated when the measurement laser light is irradiated to the detection target. The return light is a part of the wave formed on the sea surface. This also occurs when a measurement laser beam is irradiated on a portion (a wave rising region or a white wave formed by breaking a part of the wave).
However, the wave at sea is usually lower in height than a ship or the like that is a detection target of the three-dimensional laser radar device. For this reason, as a matter of course, the height of a part of such waves is slightly smaller than that of a ship or the like.
It should be noted that the traveling direction of the wave is considered to be the front-rear direction with respect to the three-dimensional laser radar device or the left-right direction with respect to the three-dimensional laser radar device. The area where the return light that reaches the three-dimensional laser radar device when the measurement laser light is irradiated varies in size depending on the traveling direction of the wave. However, the height of this region does not exceed the magnitude of the wave and is sufficiently small compared to a ship or the like. That is, the height of a partial region of the wave that is detected by the three-dimensional laser radar device is always smaller than that of a ship or the like regardless of the traveling direction of the wave.

The present invention is based on such knowledge, and the height distance of the continuous point data group among the continuous point data group formed by grouping a plurality of point data continuously arranged in the vertical direction is a wave. A configuration is adopted in which the detection target is detected by excluding the point data included in the continuous point data group that is equal to or lower than the exclusion threshold set with the assumed maximum value as an upper limit.
According to the present invention employing such a configuration, the point data included in the continuous point data group having a height equal to or lower than the exclusion threshold set with the assumed maximum value of the wave as the upper limit (that is, the measurement laser beam is a wave of the wave). The point data obtained by receiving the return light generated by being scattered by a part is deleted, and the detection target is detected.
In other words, according to the present invention, no matter where the sea level position exists, point data obtained by reflecting the measurement laser beam to a part of the wave is excluded, so it is possible to remove a ship or the like without acquiring the sea level position. Can be detected.

  Therefore, according to the present invention, it becomes possible to reliably detect a detection object regardless of the sea surface position, and it is not necessary to mount a GPS, a radio clock, a gyrocompass, etc. It can also be mounted on a moving object.

It is a block diagram which shows schematic structure of the three-dimensional laser radar apparatus in one Embodiment of this invention. It is explanatory drawing which shows typically distribution of the point data obtained with the three-dimensional laser radar apparatus in one Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the three-dimensional laser radar apparatus in one Embodiment of this invention. It is a block diagram which shows schematic structure of the modification of the laser sensor apparatus in one Embodiment of this invention. FIG. 5 is a three-side view and a cross-sectional view showing, in an enlarged manner, a polygon mirror provided in a modification of the laser sensor device according to the embodiment of the present invention shown in FIG. 4 and its periphery. FIG. 5 is a schematic diagram showing, in an enlarged manner, a polygon mirror provided in a further modification of the modification of the laser sensor device according to the embodiment of the present invention shown in FIG. 4 and its surroundings.

  Hereinafter, an embodiment of a laser radar device and a laser radar method according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

FIG. 1 is a block diagram showing a schematic configuration of a three-dimensional laser radar device S1 (laser radar device) of the present embodiment.
The three-dimensional laser radar device S1 of the present embodiment detects a ship (detection target) by irradiating a measurement laser beam to a measurement space (an area where the detection target may exist). Yes, when a ship is present in the measurement space, a signal indicating the position of the ship is output.
As shown in FIG. 1, the three-dimensional laser radar device S1 of this embodiment includes a laser projector 1, a light receiver 2, a polygon scanner 3, a galvano scanner 4, a distance calculator 5, and a signal processing unit. 6 (signal processing means) and a controller 7.

  The laser projector 1 emits the measurement laser beam L1 toward the polygon scanner 3 and emits the measurement laser beam L1 based on the projection command input from the controller 7.

The light receiver 2 receives return laser light L2 (return light) generated by reflection (including specular reflection and diffuse reflection) of the measurement laser light L1, converts it into an electrical signal, and outputs it. 3, the return laser beam L <b> 2 guided by 3 is received.
The light receiver 2 outputs a pulse signal when receiving the return laser light L2, that is, outputs light reception timing information of the return laser light L2. The light receiver 2 is electrically connected to the distance calculator 5 and inputs the light reception timing information to the distance calculator 5.

The polygon scanner 3 guides the measurement laser beam L1 and the return laser beam L2, and continuously rotates a polygon mirror having a peripheral surface as a reflection surface about a rotation axis arranged horizontally. The laser beam L1 is scanned in the vertical direction.
The polygon scanner 3 operates based on a speed command input from the controller 7.

The galvano scanner 4 guides the measurement laser beam L1 and the return laser beam L2, and scans the measurement laser beam L1 in the horizontal direction by rotating a galvano mirror whose surface is a reflection surface in a horizontal plane. Is.
The galvano scanner 4 operates based on a speed command input from the controller 7.

As the polygon scanner 3 and the galvano scanner 4 work together, the measurement laser beam L1 is scanned in the vertical direction and the horizontal direction.
The polygon scanner 3 is suitable for scanning the measurement laser beam L1 at a higher speed than the galvano scanner 4. In this embodiment, as described above, the polygon scanner 3 scans the measurement laser beam L1 in the vertical direction, and the galvano scanner 4 scans the measurement laser beam L1 in the horizontal direction.
For this reason, in the three-dimensional laser radar device S1 of the present embodiment, the polygon scanner 3 and the galvano scanner 4 work together to increase the moving speed in the vertical direction from the moving speed in the horizontal direction, thereby measuring the laser beam L1 for measurement. Are scanned, and so-called vertical raster scanning is performed.
Thus, in the three-dimensional laser radar device S1 of the present embodiment, the scanning means of the present invention is constituted by the polygon scanner 3 and the galvano scanner 4.

The distance calculator 5 calculates the distance to the reflector that reflects the measurement laser beam L1 existing in the measurement space.
More specifically, the distance calculator 5 receives a light projection command input from the controller 7 to the laser projector 1 at the same time, and the difference between the input timing of this light projection command and the light reception timing input from the light receiver 2. The distance from the reflector to the reflector is calculated.
The distance calculator 5 inputs the calculated distance information to the signal processing unit 6 as measurement information.

As shown in FIG. 2, the signal processing unit 6 distributes point data indicating that the return laser beam L2 exists on the global coordinate system indicating the measurement space.
For example, when the measurement information is input from the distance calculator 5, the signal processing unit 6 determines the position where the return laser beam L <b> 2 that is the basis of the measurement information is generated from the measurement laser beam input from the controller 7. Point data is plotted at the position where the return laser beam L2 is generated on the global coordinate system, obtained from the irradiation position of L1. The irradiation position of the measurement laser beam L1 can be obtained from angle information input from the polygon scanner 3 and the galvano scanner 4 via the controller 7.
In FIG. 2, the position indicated by the black circle is the position where the point data is plotted. In FIG. 2, point data is plotted on a plane for easy understanding of the future explanation. However, the actual global coordinate system has a depth direction in addition to the plane shown in FIG. The point data is plotted three-dimensionally.

  The signal processing unit 6 determines a horizontal angle φ (rotation angle of the galvano scanner 4), a vertical angle θ (rotation angle of the polygon scanner 3), and a distance R (distance information) for each point data. Store it in association. That is, the point data obtained by the signal processing unit 6 in the present embodiment indicates coordinates in the polar coordinate system.

  In the signal processing unit 6, when the measurement laser beam L 1 is scanned over the entire area of the measurement space, the point data is distributed in the entire area of the global coordinate system viewed from the light receiver 2 to Distribution data including the presence or absence of point data at each location is acquired.

In the laser radar device S1 of this embodiment, the signal processing unit 6 extracts a continuous point data group composed of a plurality of continuous point data in the global coordinate system, and the height distance of the continuous point data group is on the sea. Detection of a detection target is performed by excluding point data included in a small continuous point data group that is equal to or less than an exclusion threshold set with the assumed maximum value of the generated wave as an upper limit.
The processing in the signal processing unit 6 will be described in detail later with reference to the flowchart shown in FIG.

  Returning to FIG. 1, the controller 7 controls the entire operation of the three-dimensional laser radar device S <b> 1 of the present embodiment. The laser projector 1, the polygon scanner 3, the galvano scanner 4, and the distance calculator 5 The signal processing unit 6 is electrically connected.

Next, the operation (laser radar method) of the three-dimensional laser radar device S1 of the present embodiment will be described with reference to FIG.
In the following description, the operation subject is the signal processing unit 6 that performs processing under the control of the controller 7. Further, in the following description, the signal processing unit 6 will be described starting from a state in which point data is acquired in all regions of the global coordinate system viewed from the light receiver 2. However, the following operations are not necessarily started from a state in which point data is acquired in the entire area of the global coordinate system, and may be advanced while acquiring point data in order to shorten the processing time.

First, the signal processing unit 6 extracts the point data continuously arranged in the vertical direction among the point data plotted in the global coordinate system shown in FIG. 3 as a continuous point data group (step S1).
Here, the point data being continuously arranged in the vertical direction means that the two point data are arranged in the vertical direction and have a separation distance within an adjacent distance. Note that the adjacent distance is a distance that is likely to be a single detection target, and can be arbitrarily set within a range that does not exceed the resolution of the three-dimensional laser radar device S1. Specifically, since the detection target in the present embodiment is a ship, it is conceivable to set the adjacent distance to about 20 cm.
The signal processing unit 6 stores the adjacent distance in advance, converts the point data arranged in the vertical direction from polar coordinates to orthogonal coordinates, calculates the distance between these point data, and the calculated distance is the above-described adjacent distance. When the distance is equal to or shorter than the distance, these point data are set as a single continuous point data group.

Here, when three or more point data are continuous in the vertical direction and the distance between adjacent point data is within the adjacent distance, the signal processing unit 6 converts all these point data into one continuous data. Extract as point data group. That is, the signal processing unit 6 groups all point data connected in a line in the vertical direction as one continuous point data group. As a result, a continuous point data group indicated by being surrounded by a solid line in FIG. 2 is extracted.
In the three-dimensional laser radar device S1 of the present embodiment, the signal processing unit 6 deletes point data that does not belong to the continuous point data group (that is, point data that is not continuous in the vertical direction).

  Subsequently, the signal processing unit 6 determines whether or not the height distance of the continuous point data group extracted in step S1 is equal to or less than an exclusion threshold value stored in advance (step S2).

Here, the exclusion threshold is a height distance that is set with an assumed maximum value of a wave assumed to occur on the sea included in the measurement space as an upper limit.
Note that only a part of the region where the return light L2 that reaches the light receiver 2 in the wave is generated when the measurement laser beam L1 is irradiated. For this reason, it is also possible to acquire the area | region which generate | occur | produces the return light L2 which reaches | attains the light receiver 2 by experiment or simulation, and to set the said exclusion threshold value based on this acquired value.
That is, in the present invention, the exclusion threshold value does not need to be the assumed maximum value of the wave. For example, the height distance based on the region that generates the return light L2 reaching the light receiver 2 is the minimum value, and the maximum wave The height distance can be set as the maximum value.
Note that the assumed maximum value of the wave here may be, for example, the maximum wave height assumed when the sea surface is calm, or the maximum wave height assumed when the sea surface is rough. It may be set appropriately depending on the environment in which the three-dimensional laser radar device S1 is installed and the detection target to be detected.

  As described above, the vertical size of the wave in the global coordinate system is always small regardless of the traveling direction of the wave. For this reason, the exclusion threshold does not become a large value, but becomes a small value as compared with the size of the ship in the global coordinate system.

If the signal processing unit 6 determines in step S2 that the height distance of the continuous point data group is equal to or less than the exclusion threshold value, the signal processing unit 6 deletes the point data belonging to the continuous point data group (step S3). .
On the other hand, if it is determined in step S2 that the height distance of the continuous point data group is not less than or equal to the exclusion threshold, the signal processing unit 6 stores the continuous point data group as a partial point data group indicating the detection target. To do.

  Subsequently, the signal processing unit 6 determines whether or not the processing shown in Steps S1 to S4 has been completed for all point data (Step S5), and proceeds to Steps S1 to S4 for all point data. Until the processing shown is completed, the target point data is changed and Steps S1 to S4 are repeated.

If the signal processing unit 6 determines that the processing of all the point data has been completed in step S5, the object point data group indicating the ship by grouping the adjacent partial point data groups in the global coordinate system. Is generated (step S6).
Here, the signal processing unit 6 determines whether the adjacent partial point data groups exist within the adjacent distance used in step S1. Group as a single vessel.

Finally, the signal processing unit 6 calculates the distance and direction to the detection target based on the object point data group obtained in step S6, and sets the position of the ship to the outside together with the presence or absence of the ship. Output.
Note that the position of the ship may be obtained by obtaining the center of the ship from the object point data group and using the center position, or by obtaining the center of gravity of the ship from the object point data group.

According to the three-dimensional laser radar device S1 and the three-dimensional laser radar method of the present embodiment as described above, continuous point data whose height distance in the global coordinate system is equal to or less than the exclusion threshold value set with the assumed maximum value of the wave as an upper limit. The point data included in the group is deleted, and the ship is detected.
That is, according to the three-dimensional laser radar device S1 and the three-dimensional laser radar method of the present embodiment, it is possible to prevent a wave from being erroneously detected as a ship wherever the sea level exists.
Therefore, according to the three-dimensional laser radar device S1 and the three-dimensional laser radar method of the present embodiment, since the point data obtained by reflecting the measurement laser beam to a part of the wave is excluded, the sea level position is acquired. A ship etc. can be detected without doing.
That is, according to the three-dimensional laser radar device S1 and the three-dimensional laser radar method of the present embodiment, it becomes possible to reliably detect a detection object regardless of the sea surface position, and GPS, a radio-controlled clock, a gyrocompass, etc. It is not necessary to mount, and it can be mounted not only on land but also on moving bodies such as ships.

Further, in the three-dimensional laser radar device S1 of the present embodiment, point data obtained by reflecting the measurement laser beam to a part of the wave is excluded, and therefore within the adjacent distance of the excluded point data. There is no need to calculate whether or not other point data exists.
For this reason, according to the three-dimensional laser radar device S1 of the present embodiment, it is possible to reduce the load on the signal processing unit 6 when generating the object point data group.

In the three-dimensional laser radar apparatus S1 of the present embodiment, the measurement laser beam L1 is scanned by using the polygon scanner 3 and the galvano scanner 4 so that the vertical movement speed is higher than the horizontal movement speed. A configuration (so-called raster scan) is realized.
In this way, by scanning the measurement laser beam L1 with the vertical movement speed higher than the horizontal movement speed, the acquisition timing of point data continuous in the vertical direction approaches, and the wave traveling speed increases in the front-rear direction. Even in a fast case, it is possible to prevent point data indicating the wave from being acquired in a wider range than the actual wave size.
For this reason, according to the three-dimensional laser radar device S1 of the present embodiment, it is possible to further improve the ship detection accuracy.

In addition, by adopting so-called raster scan, the acquisition timing of point data continuously arranged in the vertical direction (point data constituting the continuous point data group) is continuous in time series.
For this reason, when performing the above-described operation while performing raster scanning, it is possible to immediately extract a continuous point data group while acquiring point data, and immediately add a continuous point data group having a height equal to or less than the exclusion threshold. Constituting point data can be excluded. Therefore, point data that is not required in the shortest time can be excluded, and the burden on the signal processing unit 6 can be further reduced.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

For example, in the above embodiment, the configuration in which the detection target to be detected is a ship has been described.
However, the present invention is not limited to this, and even if the detection target to be detected is something other than a ship, it can be detected if its size is sufficiently large with respect to waves. Is possible.

Moreover, in the said embodiment, the structure which moves the measurement laser beam L1 to a perpendicular direction faster than a horizontal direction was employ | adopted.
However, when the moving speed of the measurement laser beam L1 is sufficiently higher than the traveling speed of the waves and the ship, the above configuration need not be concerned.

In the above-described embodiment, the configuration in which the scanning unit includes the polygon scanner 3 and the galvano scanner 4 has been described.
However, the present invention is not limited to this, and the scanning unit can be configured using another scanner such as a scanner using a rotating prism.
Also, scanning means that can rotate around two axes that intersect the polygon mirror without the galvanometer mirror, scanning means that can rotate around the two axes that intersect the galvanometer mirror without the polygon mirror, or It is also possible to use scanning means that uses a polygon scanner for horizontal scanning and a galvano scanner for vertical scanning.

Hereinafter, another embodiment of the laser radar device will be described.
FIG. 4 is a block diagram showing a schematic configuration of the laser sensor device S2.
FIG. 5 is a three-side view and a cross-sectional view showing the polygon mirror included in the laser sensor device S2 and the periphery thereof in an enlarged manner.
The laser sensor device S2 performs measurement by irradiating a measurement laser beam to a measurement target area (an area where the measurement target may exist), and the measurement target exists in the measurement target area. When doing so, a signal indicating the position and shape of the measurement object is output.
As shown in FIG. 4, the laser sensor device S2 includes a laser projector 11, a light receiver 12, a polygon mirror 13, a rotation motor 14, a rotation motor 15, a distance calculator 16, and a controller. 17.

The laser projector 11 emits the measurement laser light L1 toward the peripheral surface (reflection surface) of the polygon mirror 13, and as shown in FIG. 5, the light projection light source 11a serving as the light source of the measurement laser light L1. A projection cover 11b that surrounds and protects the projection light source 11a, and a projection lens 11c that guides the measuring laser beam L1 emitted from the projection light source 11a toward the polygon mirror 13.
The laser projector 11 emits the measurement laser beam L1 based on the projection command input from the controller 17.

The light receiver 12 receives the return laser light L2 generated by irradiating and reflecting the measurement laser light L1 on the object to be measured, converts it into an electrical signal, and outputs it. The peripheral surface of the polygon mirror 13 ( The return laser beam L2 reflected and guided by the reflecting surface is received.
As shown in FIG. 5, the light receiver 12 includes a light receiving element 12a that converts the return laser light L2 into an electric signal, a light receiving cover 12b that surrounds and protects the light receiving element 12a, and a return reflected from the polygon mirror 13. And a light receiving lens 12c for guiding the laser light L2 toward the light receiving element 12a.
The light receiver 12 outputs a pulse signal when receiving the return laser light L2, that is, outputs light reception timing information of the return laser light L2. The light receiver 12 is electrically connected to the distance calculator 16 and inputs the light reception timing information to the distance calculator 16.

As shown in FIG. 5, these laser projector 11 and light receiver 12 are supported by a support mechanism (not shown) and fixed in the direction of the rotation axis La of the polygon mirror 13 with respect to the side plate 8 fixed to the installation surface. It is installed side by side.
As will be described in detail later, in the laser sensor device S2, the polygon mirror 13 is rotated about a rotation axis Lb shown in FIG. When the polygon mirror 13 is rotated, the positional relationship between the laser projector 11 and the light receiver 12 and the polygon mirror 13 is greatly shifted, and the measurement laser beam L1 and the return laser beam L2 are separated from the peripheral surface of the polygon mirror 13. The laser projector 11 and the light receiver 12 are arranged as close to the rotation axis Lb as possible so as not to come off.

The polygon mirror 13 is a light guide member that is square in plan view and has a reflection surface that guides the measurement laser beam L1 and the return laser beam L2 as a peripheral surface.
The polygon mirror 13 in this embodiment is rotated about the rotation axis La by the rotation motor 14 and is divided into two in the direction of the rotation axis La by the slit 19 as shown in FIG.
More specifically, the polygon mirror 13 is divided by the slit 19 into a measurement laser beam guide 13a that guides the measurement laser beam L1 and a return laser beam guide 13b that guides the return laser beam L2. .
A shaft portion 110 connected to the rotation motor 14 is attached to the polygon mirror 13 so that the polygon mirror 13 is rotated when the shaft portion 110 is rotationally driven by the rotation motor 14. .

  As shown in FIG. 5, the laser sensor device S <b> 2 includes a housing case 111 that houses the polygon mirror 13 and a light shielding plate 112 (light shielding portion) disposed inside the housing case 111.

  In the present embodiment, the storage case 111 includes a window portion 111a and a support portion 111b as shown in FIG.

The window part 111a is a part through which the measurement laser beam L1 and the return laser beam L2 can pass, and is formed of, for example, an acrylic material. This window part 111a is arrange | positioned toward the side which laser sensor apparatus S2 performs a measurement, and is being fixed with respect to the installation surface by the support mechanism not shown.
As shown in FIG. 5, in the present embodiment, the window 111a is set in an arc shape centered on the rotation axis Lb when viewed from the direction of the rotation axis Lb.

The support part 111 b supports the polygon mirror 13 fixed to the shaft part 110 by supporting the shaft part 110, and forms a region other than the window part 111 a of the housing case 111.
The support 111b is made of a material that is opaque to the measurement laser light L1 and the return laser light L2, and is made of the same material as the light shielding plate 112, for example.
And the support part 111b has the opening which can pass the laser beam L1 for a measurement, and the return laser beam L2 in the window part 111a side and the laser projector 11 and the light receiver 12 side.

In the present embodiment, the support portion 111b is mechanically connected to the rotation motor 15, and a support mechanism (not shown) is rotatable by the rotation motor 15 about the rotation axis Lb shown in FIG. It is pivotally supported by.
Note that the tip 111c of the support 111b on the side of the window 111a is disposed to face the window 111a with a slight gap.
Here, the window 111a of the housing case 111 is fixed to the installation surface, and the support 111b is pivotally supported. For this reason, when the support part 111b is rotated, the positional relationship between the window part 111a and the support part 111b changes. However, since the window portion 111a is set in an arc shape centering on the rotation axis Lb, a slight gap is always maintained from the tip 111c on the window portion 111a side of the support portion 111b to the window portion 111a. It will be.

The light shielding plate 112 is disposed inside the housing case 111, and the measurement laser light guide space K1 (first space) extending from the laser projector 11 to the measurement laser light guide portion 13a of the polygon mirror 13 in the housing case 111. And a return laser light guide space K2 (second space) from the return laser light guide portion 13b of the polygon mirror 13 to the light receiver 12.
The light shielding plate 112 is made of a material opaque to the measurement laser light L1 and the return laser light L2, and the light enters the return laser light guide space K2 from the measurement laser light guide space K1, and This prevents light from entering the laser beam guide space K1 from the laser beam guide space K2.
In the laser sensor device S2, the light shielding plate 112 is also disposed in the slit 19 of the polygon mirror 13, whereby the space surrounded by the support 111b by the light shielding plate 112 is completely measured. The light guide space K1 and the return laser light guide space K2 are isolated.
Note that the tip 112a of the light shielding plate 112 on the side of the window 111a is disposed to face the window 111a with a slight gap. The light shielding plate 112 is rotated around the rotation axis Lb as the support portion 111b rotates. At this time, the light shielding plate 112 always has a slight distance from the tip 112a on the window 111a side to the window 111a. It is kept in a gap.

Returning to FIG. 4, the rotation motor 14 scans the measurement laser beam L <b> 1 in the direction (first direction) orthogonal to the rotation axis La and the optical axis by rotating the polygon mirror 13. Is connected to the shaft portion 110 (see FIG. 5).
In the present embodiment, the rotation axis La is disposed horizontally. For this reason, when the polygon mirror 13 is rotated, the measurement laser beam L1 is scanned in the vertical direction.
The rotation motor 14 rotates the polygon mirror 13 based on a speed command input from the controller 17. The rotation motor 14 is provided with an encoder (not shown), and angle information of the rotation motor 14 is input to the controller 17 from the encoder.

The rotation motor 15 rotates the polygon mirror 13 pivotally supported by the support portion 111b about the rotation axis Lb by rotating the support portion 111b of the housing case 111 about the rotation axis Lb. Is.
Here, the rotation axis Lb is a central axis that is orthogonal to (intersects) the rotation axis La (the central axis of rotation by the rotation motor 14). For this reason, when the polygon mirror 13 is rotated by the rotation motor 15, the measurement laser beam L1 is scanned in a direction (second direction) different from the scanning direction by the rotation about the rotation axis La of the polygon mirror 13. Is done.
In the present embodiment, the rotation axis Lb is arranged to be vertical. For this reason, the measurement laser beam L1 is scanned in the horizontal direction by rotating the polygon mirror 13.
The rotation motor 15 rotates the polygon mirror 13 based on a speed command input from the controller 17. The rotation motor 15 is provided with an encoder (not shown), and angle information of the rotation motor 15 is input to the controller 17 from the encoder.

The distance calculator 16 calculates the distance to the reflector that reflects the measurement laser light existing in the measurement region, and inputs the calculation result to the controller 17 as distance information.
More specifically, the distance calculator 16 is simultaneously input with a light projection command input from the controller 17 to the laser projector 11, and the difference between the input timing of this light projection command and the light reception timing input from the light receiver 12. The distance from the reflector to the reflector is calculated.

The controller 17 controls the entire operation of the laser sensor device S2. As shown in FIG. 4, the laser projector 11, the polygon mirror 13, the rotation motor 14, the rotation motor 15, and the distance calculation are performed. It is electrically connected to the vessel 16.
The controller 17 functions as the signal processing unit 6 and the controller 7 of the above embodiment.

According to the laser sensor device S2 as described above, the measurement laser light guide space K1 from the laser projector 11 to the measurement laser light guide portion 13a of the polygon mirror 13 is caused by the light shielding plate 112, and the light shielding plate 112. The laser beam is divided into a return laser beam guide space K2 extending from the return laser beam guide 13b of the polygon mirror 13 to the light receiver 12.
That is, in the laser sensor device S2, in the internal space of the housing case 111, light enters from the measurement laser beam guide space K1 into the return laser beam guide space K2 and returns from the return laser beam guide space K2 to the measurement laser beam guide space K1. Incident light is prevented by the light shielding plate 112.
For this reason, it is possible to prevent the stray light generated by the measurement laser light L1 unintentionally reflecting in the housing case 111 from returning from the measurement laser light guide space K1 and entering the laser light guide space K2. The stray light can be prevented from reaching the light receiver 12.
Therefore, according to the laser sensor device S2, it is possible to prevent deterioration of measurement accuracy due to stray light.
By preventing the measurement accuracy from being deteriorated due to stray light in this way, it is possible to perform measurement at a long distance where the intensity of the return laser beam L2 becomes weak. Furthermore, since stray light can be prevented from entering the light receiver 12, the output of the measurement laser light L1 can be increased, and measurement at a longer distance is possible.

Further, according to the laser sensor device S2, the measurement laser beam L1 is scanned in the vertical direction by rotating the polygon mirror 13 by the rotation motor 14, and the polygon mirror 13 is rotated by the rotation motor 15. Thus, the measurement laser beam is scanned in the horizontal direction.
Therefore, by combining the rotation by the rotation motor 14 and the rotation by the rotation motor 15, the measurement laser beam L1 can be scanned in the entire three-dimensional region.
Therefore, according to the laser sensor device S2, measurement in a three-dimensional region can be performed.

Further, according to the laser sensor device S2, the measurement laser beam L1 is scanned by rotating and rotating the polygon mirror 13.
For this reason, it is possible to scan the measurement laser beam L1 without moving the entire laser sensor device S2, and thereby it is possible to scan the measurement laser beam L1 at high speed.

  As described above, according to the laser sensor device S2, it is possible to perform measurement in a three-dimensional region at high speed, and to prevent deterioration in measurement accuracy due to stray light.

Further, in the laser sensor device S2, the polygon mirror 13 has a slit 19 that is divided into a measurement laser beam guide 13a and a return laser beam guide 13b, and a light shielding plate 112 is also disposed in the slit 19. Yes.
For this reason, the inside of the support portion 12b can be completely separated into the measurement laser light guide space K1 and the return laser light guide space K2, and stray light can be prevented from entering the light receiver 12 more.

Further, in the laser sensor device S2, the housing case 111 is formed so as to be able to pass the measurement laser beam L1 and the return laser beam L2, and the rotation center (rotation axis Lb) of the polygon mirror 13 by the rotation motor 15 is formed. And a support portion 111b that supports the polygon mirror 13 and is rotated together with the polygon mirror 13 by the rotation motor 15.
For this reason, the polygon mirror 13 can be rotated without rotating the entire storage case 111, and foreign matter can be prevented from entering the storage case 111.

Further, the laser sensor device S2 may adopt a form as shown in FIG.
FIG. 6 is an enlarged schematic view showing the polygon mirror 13 provided in the laser sensor device S2 and the periphery thereof.
As shown in this figure, the laser sensor device S2 includes a light shielding tube 13 in the return laser light guide space K2.
The light shielding tube 13 is disposed between the return laser light guide 13b and the light receiver 12, and surrounds the optical path of the return laser light L2 between the return laser light guide 13b and the light receiver 12. is there.
The light shielding cylinder 13 is formed of, for example, a material that is opaque to visible light, and prevents disturbance light (including stray light) from entering the inner region of the light shielding cylinder 13.

According to the laser sensor device S2 having such a configuration, disturbance light can be prevented from reaching the light receiver 12 by the light shielding tube 13.
Therefore, the measurement accuracy can be further improved.

The laser sensor device S2 employs a configuration in which the rotation axis La and the rotation axis Lb are orthogonal to each other.
However, if the rotation axis La and the rotation axis Lb intersect, it is possible to scan the measurement laser beam L1 in a three-dimensional region.

In the laser sensor device S2, the configuration in which the rotation axis La is set horizontally and the rotation axis Lb is set vertical has been described.
However, the rotation axis La may be set to be vertical and the rotation axis Lb may be set to be horizontal.

In the laser sensor device S2, the configuration in which the shape of the polygon mirror 13 viewed from the direction of the rotation axis La is square has been described.
However, the shape of the polygon mirror 13 viewed from the direction of the rotation axis La can be a polyhedron with a triangle or more.

  S1, S2 ... Three-dimensional laser radar device (laser radar device), 2 ... Light receiver, 3 ... Polygon scanner, 4 ... Galvano scanner, 6 ... Signal processing unit (signal processing means), L1 ... Measurement Laser light, L2 ... Return laser light (return light)

Claims (4)

A laser radar device that detects a detection object at sea from a distribution of point data obtained by projecting a measurement laser beam while scanning the measurement space and receiving a return light of the measurement laser beam with a light receiver. Because
Consecutive point data below the exclusion threshold that is set with the assumed maximum height distance of waves generated at sea as the upper limit among the continuous point data group consisting of a plurality of the point data arranged continuously in the vertical direction. A laser radar apparatus comprising: signal processing means for detecting the detection target object excluding the point data included in a group.   2. The laser radar apparatus according to claim 1, further comprising a scanning unit that scans the measurement laser beam with a moving speed in a vertical direction higher than a moving speed in a horizontal direction. The scanning means includes
A polygon scanner that scans the measuring laser beam in a vertical direction;
The laser radar apparatus according to claim 2, further comprising: a galvano scanner that scans the measurement laser beam in a horizontal direction. A laser radar method for detecting a detection object at sea from a distribution of point data obtained by projecting a measurement laser beam while scanning the measurement space and receiving a return light of the measurement laser beam with a light receiver. Because
Consecutive point data below the exclusion threshold that is set with the assumed maximum height distance of waves generated at sea as the upper limit among the continuous point data group consisting of a plurality of the point data arranged continuously in the vertical direction. A laser radar method, wherein the detection object is detected by excluding the point data included in a group.

Images