JP2010044050A - Method of recognizing posture of laser radar and laser radar - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of recognizing a posture of a laser radar for largely shortening construction time in setting a monitor region on a ground coordinate of a crossing, setting the monitor region with high accuracy irrespective of a skill of a construction worker, and setting the monitor region in the daytime, and the laser radar. <P>SOLUTION: The laser radar includes a light projection part 2 for emitting laser light LT, a scanning part 3 for scanning the laser light LT, a light reception part 4 for receiving reflected laser light LR reflected back by a target T of measurement, a control part 5 for controlling projection timing of the laser light LT and the scanning of the scanning part 3, a calculation part 6 for obtaining three-dimensional information of the target from the projection timing of the laser light LT and reception timing of the reflected laser light LR, and laser light reflectors 7 provided at four corners of the monitor region E. The calculation part 6 calculates a distance measurement origin position by the ground coordinate and an installed posture from polar coordinate system position data obtained by measuring respective positions of the laser light reflectors 7 set at four positions. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser radar attitude recognition method and a laser radar used to determine the distance measurement origin position and installation attitude of a laser radar that monitors the presence or absence of a person in a railroad crossing or an intersection, for example. .

  Conventionally, as the above-described laser radar, for example, a light projecting unit that emits laser light, a scanning unit that two-dimensionally scans the laser light emitted from the light projecting unit, and laser light that has been reflected and returned from the measurement target And a control unit that issues a laser beam projection command to the light projecting unit and controls scanning by the scanning unit. In this laser radar, the light projection timing of the laser beam given from the control unit And the polar coordinate system three-dimensional data to be measured is acquired based on the light receiving timing of the reflected laser beam given from the light receiving unit.

  In a laser radar that measures data in such a polar coordinate system, for example, when installed at a railroad crossing, in order to set a monitoring area (surface area and height area) that is a measurement area in the ground coordinate system, It is necessary to obtain the distance measurement origin position and orientation of the laser radar with respect to the system, and to perform coordinate conversion processing of polar coordinate system three-dimensional data based on these distance measurement origin position and orientation.

  Specifically, first, in the ground coordinate system in which the surface area of the monitoring area is the XY plane and the normal direction of the XY plane is the Z axis, the center of the monitoring area defined as the origin or the laser radar The laser radar distance measurement origin position for a point below the vertical is obtained from a design drawing or an actual measurement value by a measuring instrument. Next, for the pitching amount and rolling amount of the posture, the inclination when the laser radar is installed is an angle meter. The yawing amount in the posture is obtained from a design drawing or an actually measured value by a measuring instrument.

  Then, based on the distance measurement origin position and orientation of the laser radar obtained as described above, the polar coordinate system three-dimensional data, which is the measurement data of the laser radar, is transformed into the ground coordinate system, and the monitoring area in this ground coordinate system Is set from actually measured values by surveying (see, for example, Patent Documents 1 and 2).

JP 2006-194617 Patent No. 3472815

  However, in the past, when installing a laser radar based on the design drawing, it was found that there was a structure or buried object at the installation planned position at the time of construction, and the plan may be forced to change, When a laser radar is installed based on an actual measurement value obtained by surveying, measurement errors of the laser radar installation position measurement, attitude measurement, and monitoring area position measurement are accumulated. Therefore, there is a problem that the installation time becomes longer and the construction time becomes longer, and the setting accuracy changes depending on the skill level of the worker who matches the site.

When measuring the installation position and orientation of the laser radar, measure the distance from the point defined as the origin in the ground coordinate system to the distance measurement origin position of the laser radar with a tape measure or non-contact distance meter. Since it is necessary, it has a problem that it is difficult to work during the day when pedestrians and vehicles pass through, and it has been a conventional problem to solve these problems.
The present invention has been made paying attention to the above-described conventional problems. For example, when setting a monitoring area in the ground coordinate system at a railroad crossing, the construction time can be significantly reduced, and the construction worker's skill can be achieved. It is possible to set the monitoring area with high accuracy regardless of the degree, and in addition, the posture recognition method of the laser radar capable of performing the monitoring area setting operation even during the day when pedestrians and vehicles pass It aims to provide a laser radar.

  According to the first aspect of the present invention, the projected laser beam is two-dimensionally scanned, and the laser beam is projected based on the projection timing of the laser beam and the reception timing of the reflected laser beam reflected back from the measurement target. A laser radar attitude recognition method for acquiring three-dimensional information of a measurement object, wherein at least three points in a scanning range of the laser radar installed at an arbitrary part are set as laser light reflection points, and then laser is emitted from the laser radar. Based on the reflected laser light reflected by the laser light reflection point and returned by scanning while projecting light, each position of the laser light reflection point is measured by the polar coordinate system of the laser radar, Each of the polar coordinate system position data of the laser light reflection point is coordinate-converted to the orthogonal coordinate system of the laser radar, and the orthogonal coordinate system position data of the laser light reflection point obtained thereby is converted to Then, plane data of the plane including the at least three laser beam reflection points is calculated by the least square method, and then the origin position is defined by the ground coordinate system from the plane data, and the laser radar for the origin position is defined. In order to solve the above-described conventional problems, the configuration of the posture recognition method of this laser radar is characterized in that the distance measurement origin position is obtained and the rotation angle with respect to the three axes orthogonal to each other is obtained as the installation posture. As a means of.

Further, in the laser radar posture recognition method according to claim 2 of the present invention, the laser light reflectors disposed at at least three locations within the scanning range of the laser radar installed at an arbitrary site are used as laser light reflection points. Yes.
On the other hand, a laser radar according to a third aspect of the present invention is a light projection unit that emits laser light, a scanning unit that scans the laser light emitted from the light projection unit two-dimensionally, and is reflected by a measurement object and returned. A light receiving unit that receives the reflected laser beam through the scanning unit, a control unit that issues a laser beam projection command to the light projecting unit and controls scanning by the scanning unit, and a laser beam that is supplied from the control unit And a calculation unit that obtains the three-dimensional information of the measurement target based on the light projection timing and the light reception timing of the reflected laser beam given from the light receiving unit, and the calculation unit sets at least three places in the scanning range. This laser radar is characterized in that it is configured to obtain the distance measurement origin position and installation posture by the ground coordinate system from the polar coordinate system position data obtained by measuring each position of the laser light reflection point. The structure has a means for solving the conventional problems described above.

Further, the laser radar according to claim 4 of the present invention is configured to include laser light reflectors arranged at laser light reflection points set in at least three places in the scanning range.
In the laser radar attitude recognition method and laser radar according to the present invention, a semiconductor laser, a solid-state laser, a gas laser, or the like can be used as the laser light emitted from the light projecting unit, and the signal waveform has a pulsed or phase-modulated sinusoidal shape. The formed laser beam is used.

In the laser radar attitude recognition method and laser radar according to the present invention, since the installation position and attitude of the laser radar itself can be obtained from the measurement data of the laser radar, the laser radar is measured based on the distance measurement origin position and the installation attitude of the laser radar. If the polar coordinate system position data of the light reflection point is coordinate-converted, the measurement area of the laser radar in the ground coordinate system is set.
In other words, for example, when setting a measurement area (monitoring area) in the ground coordinate system at a level crossing, even if there is a change in the plan at the time of construction, it is possible to respond flexibly, and actual measurement using a surveying instrument is unnecessary Accordingly, the work time can be shortened and the monitoring area can be set with high accuracy regardless of the skill level of the construction worker, and the setting work can be performed during the day.

  In addition, by defining laser light reflection points set at at least three locations within the laser radar scanning range as, for example, a crossing monitoring area, the ground coordinate system is calculated simultaneously with calculating the installation position and orientation of the laser radar itself. In this case, the monitoring area is set.

  The laser radar attitude recognition method according to claim 1 of the present invention and the laser radar according to claim 3 have the above-described configuration. For example, when setting a monitoring area in the ground coordinate system at a level crossing, The monitoring area can be set with high accuracy regardless of the level of proficiency of the construction worker, and in addition to the monitoring area even during the day when pedestrians and vehicles pass. It is possible to perform the setting work of the present invention.

  Further, the laser radar posture recognition method according to claim 2 of the present invention and the laser radar according to claim 4 have the above-described configuration. For example, when setting a monitoring area in the ground coordinate system at a railroad crossing, A very excellent effect of facilitating the work and further shortening the construction time is brought about.

It is a block diagram which shows one Embodiment of the attitude | position recognition method of the laser radar which concerns on this invention. It is explanatory drawing of the polar coordinate system and orthogonal coordinate system which made the origin the installation position of the laser radar used in the calculating part of the laser radar in FIG. It is explanatory drawing of the orthogonal coordinate system which made the origin the center of the monitoring area | region used in the calculating part of the laser radar in FIG. FIG. 2 is an explanatory plan view showing a procedure for setting a monitoring region at a level crossing using the laser radar posture recognition method in FIG. 1.

Hereinafter, a laser radar attitude recognition method and a laser radar according to the present invention will be described with reference to the drawings.
1 to 4 show an embodiment of a laser radar posture recognition method according to the present invention. In this embodiment, the laser radar posture recognition method according to the present invention is installed at a railroad crossing for monitoring purposes. A case where it is applied to a radar will be described as an example.

  As shown in FIG. 1, the laser radar 1 includes a light projecting unit 2 that emits a pulsed laser light LT, a scanning unit 3 that scans the laser light LT emitted from the light projecting unit 2 two-dimensionally, The light receiving unit 4 that receives the reflected laser light LR reflected and returned from the measurement target T within the scanning range by the scanning unit 3 through the scanning unit 3, the intensity of the laser light LT emitted from the light projecting unit 2, and the light projecting timing. And a control target 5 for controlling scanning by the scanning unit 3, and a measurement target based on the light projection timing of the laser beam LT given from the control unit 5 and the light reception timing of the reflected laser beam LR given from the light receiving unit 4 A calculation unit 6 that acquires three-dimensional information of T and a laser beam reflector (laser beam reflection point) 7 disposed at four corners of a rectangular monitoring region E are provided.

  As shown in FIG. 2, the calculation unit 6 has a polar coordinate system (measurement coordinate system; measurement distance λ, vertical scanning angle φ, horizontal scanning angle) with the origin of distance measurement, which is the installation position of the laser radar 1, as the coordinate origin. θ), an orthogonal coordinate system (sensor coordinate system: horizontal direction x, vertical direction y, depth direction z) with the distance measurement origin of laser radar 1 as the coordinate origin, and four laser beams as shown in FIG. A ground coordinate system (crossing coordinate system; track direction X, crossing direction Y, height direction Z) using the diagonal intersection P of the monitoring area E set by the reflector 7 as the origin is used.

In this case, coordinate conversion from the measurement coordinate system to the sensor coordinate system can be performed by the following equations (1) to (3).
x = λ · sin θ Formula (1)
y = λ · cos θ · sin φ Equation (2)
z = λ · cos θ · cos φ Formula (3)
In addition, the coordinate conversion from the sensor coordinate system to the level crossing coordinate system involves coordinate position (Xs, Ys, Zs) of the distance measurement origin of the laser radar 1 in the level crossing coordinate system and a triaxial tilt angle (swing tilt angle α, scan tilt). The following equations (4) to (7) can be performed using the angle σ and the coordinate inclination angle γ) as parameters.

  However, the swing inclination angle α is the inclination angle between the sensor coordinate system z-axis and the crossing coordinate system Z-axis, and is defined as the rotation angle of the sensor coordinate system x-axis. The scan inclination angle σ is the sensor coordinate system x-axis The angle of inclination with respect to the crossing coordinate system X-axis, defined as the rotation angle of the sensor coordinate system y-axis. The coordinate inclination angle γ is the angle of inclination between the sensor coordinate system y-axis and the level crossing coordinate system Y-axis, and the sensor coordinates It is defined as the rotation angle of the system z-axis.

式（４）
ここで、

Formula (4)
here,

：座標傾き角γによる回転行列 式（５）

: Rotation matrix by coordinate inclination angle γ (5)

：スキャン傾き角σによる回転行列 式（６）

: Rotation matrix by scan tilt angle σ (6)

：スイング傾き角αによる回転行列 式（７）

: Rotation matrix by swing angle α (7)

Therefore, a posture recognition procedure when the laser radar 1 is installed at a level crossing and a monitoring region setting procedure in the level crossing coordinate system will be described.
First, as shown in FIG. 4, the laser light reflectors 7 are installed at the four corners of the area set as the monitoring area E in the railroad crossing. At this time, the size, shape, and material of the laser light reflector 7 are not particularly limited as long as the laser light LT emitted from the light projecting unit 2 and scanned can be reflected without omission. Further, if there are existing objects that can reflect the laser beam LT at the four corners of the area set as the monitoring region E, they may be adopted as the laser beam reflection points.

Next, the scanning unit 3 scans while projecting the laser light LT from the light projecting unit 2, and the measurement by the arithmetic unit 6 is performed based on the reflected laser light LR reflected by the four laser light reflectors 7. Depending on the coordinate system, the position coordinates (λ ₁ , θ ₁ , φ ₁ ), (λ ₂ , θ ₂ , φ ₂ ), (λ ₃ , θ ₃ , _{φ 3), (λ 4,} θ 4, to measure phi _4), followed by the position coordinates of the sensor coordinate system of the operation unit 6 each of these polar coordinate system position data _{(x 1, y 1, z} 1) , (X ₂ , y ₂ , z ₂ ), (x ₃ , y ₃ , z ₃ ), (x ₄ , y ₄ , z ₄ ), and the four laser light reflectors obtained thereby. 7 of the sensor coordinate system position data of the plane of the monitoring region E including the four laser light reflectors 7 shown in (Expression 8) by the least square method. Degree calculating equation (plane data).
ax + by + cz + d = 0 (Formula 8)

Next, based on the equation of the plane, calculation is made by (Equation 9) to (Equation 11) to obtain the installation position Zs, the swing inclination angle α, and the scan inclination angle σ of the laser radar 1 in the height direction.
Zs = | d | / {(a ² + b ² + c ² )} ^1/2 + Z ₀ (where Z ₀ = reflector height) (Formula 9)
α = arctan (−b / c) (Formula 10)
σ = arctan {a / (b · sin α−c · cos α)} (Formula 11)

  Then, by using the installation position Zs in the height direction among the installation positions of the laser radar 1 obtained in this way and the swing inclination angle α and the scan inclination angle σ of the posture, the monitoring region E is expressed by (Equation 12). Is converted into a temporary crossing coordinate system (X ′, Y ′, Z). The provisional crossing coordinate system refers to a crossing coordinate system in which the installation position (Xs, Ys) = (0, 0) of the laser radar 1 and the coordinate inclination angle γ = 0.

（式１２）

(Formula 12)

Subsequently, the coordinates (X′center, Y′center) of the diagonal intersection point P of the monitoring area E are defined as the origin, and the temporary laser radar 1 installation position (X ′s, Y's) is calculated.
X ′s = −X′center (Formula 13)
Y's = -Y'center (Formula 14)

Further, based on the parameters obtained so far, in the measured surface image of the monitoring region E, the crossing direction of the crossing is input by a straight line via a man-machine interface (not shown), and the end point of the input straight line From the coordinates (X′a, Y′a) and (X′b, Y′b), the coordinate inclination angle γ in the attitude of the laser radar 1 is obtained by calculation according to (Expression 15).
γ = −arctan ((X′b−X′a) / (Y′b−Y′a)) (Formula 15)

Furthermore, based on the coordinate inclination angle γ obtained in this way, from the installation position (X ′s, Y ′s) of the laser radar 1 in the temporary crossing coordinate system, (Equation 16) and (Equation 17). The distance measurement origin position (Xs, Ys) that is the installation position of the laser radar 1 in the crossing coordinate system is obtained by calculation.
Xs = X ′s · cos γ−Y ′s · sin γ (Formula 16)
Ys = X ′s · sinγ + Y ′s · cosγ (Formula 17)

  That is, from the plane data shown in (Equation 8), the coordinates (X'center, Y'center) of the diagonal intersection P of the monitoring area E are defined as the origin by the crossing coordinate system, and the laser radar 1 is installed at this origin position. The distance measurement origin position (Xs, Ys, Zs), which is the position, is obtained, and the rotation angles (swing inclination angle α, scan inclination angle σ, coordinate inclination angle γ) with respect to the three axes orthogonal to each other are obtained as the installation posture.

Thereafter, the positions of the four corners of the monitoring region E measured by the measurement coordinate system of the calculation unit 6 as described above, that is, the positions of the laser light reflector 7 are represented by (λ ₁ , θ ₁ , φ ₁ ), ( λ ₂ , θ ₂ , φ ₂ ), (λ ₃ , θ ₃ , φ ₃ ), (λ ₄ , θ ₄ , φ ₄ ), the distance measurement origin position (Xs, Ys) that is the installation position of the laser radar 1 described above , Zs) and the installation posture (swing inclination angle α, scan inclination angle σ, coordinate inclination angle γ), the monitoring area E in the crossing coordinate system is set.

As described above, in the laser radar posture recognition method according to the above-described embodiment, the installation position and posture of the laser radar 1 itself can be obtained from the measurement data of the laser radar 1, and therefore, the monitoring region E in the railroad crossing coordinate system is defined at the railroad crossing. When setting, even if there is a change in the plan at the time of construction, it will be possible to respond flexibly.
In addition, since actual measurement using a surveying instrument becomes unnecessary, the work time can be shortened by that amount, and the monitoring area E can be set with high accuracy regardless of the skill level of the construction worker. Thus, there is no need to measure the distance from the point defined as the origin in the railroad crossing coordinate system to the distance measurement origin position, which is the installation position of the laser radar 1, with a tape measure or a non-contact distance meter. Even in the passing time zone, the setting operation of the monitoring area E can be performed.

Further, as in the laser radar attitude recognition method according to this embodiment, if the laser light reflectors 7 arranged at four locations within the scanning range of the laser radar 1 are defined as the monitoring area E of the level crossing, the laser radar 1 itself At the same time when the installation position and orientation are calculated, the monitoring area E in the crossing coordinate system is set.
In the above-described embodiment, the case where the laser radar attitude recognition method according to the present invention is applied to a laser radar installed for monitoring at a crossing is described as an example, but the present invention is not limited to this. As another application example, for example, the present invention may be applied to a laser radar installed for monitoring at an intersection.

  In the above-described embodiment, the laser light reflectors 7 that are laser light reflection points are arranged at four locations in the scanning range of the laser radar 1, but the present invention is not limited to this, and the laser light reflection is not limited thereto. It is sufficient if the laser light reflectors 7 (or laser light reflection points), which are dots, are arranged (or set) at least at three locations within the scanning range of the laser radar 1.

DESCRIPTION OF SYMBOLS 1 Laser radar 2 Light projection part 3 Scanning part 4 Light receiving part 5 Control part 6 Calculation part 71,72,73,74 (7) Laser light reflector (laser light reflection point)
E Monitoring area (measurement area)
LR Reflected laser beam LT Projected laser beam

Claims (4)

Laser radar that scans the projected laser beam two-dimensionally and acquires the three-dimensional information of the measurement target based on the projection timing of the laser beam and the reception timing of the reflected laser beam reflected and returned from the measurement target The posture recognition method of
After setting at least three places in the scanning range of the laser radar installed in an arbitrary part as a laser beam reflection point,
Each position of the laser beam reflection point is measured by the polar coordinate system of the laser radar based on the reflected laser beam which is scanned while projecting the laser beam from the laser radar and reflected by the laser beam reflection point. And
Subsequently, each polar coordinate system position data of the laser beam reflection point is coordinate-converted into an orthogonal coordinate system of the laser radar, and at least two based on the orthogonal coordinate system position data of the laser beam reflection point thus obtained. Calculate plane data of the plane including the at least three laser light reflection points by multiplication,
Next, the origin position is defined from the plane data by the ground coordinate system, the distance measurement origin position of the laser radar with respect to the origin position is obtained, and the rotation angles with respect to the three axes orthogonal to each other are obtained as the installation posture. Laser radar attitude recognition method.   The laser radar attitude recognition method according to claim 1, wherein laser light reflectors disposed at at least three locations within a scanning range of the laser radar disposed at an arbitrary portion are used as laser light reflection points. A light emitting unit that emits laser light;
A scanning unit that two-dimensionally scans laser light emitted from the light projecting unit;
A light-receiving unit that receives the reflected laser light reflected and returned from the measurement object via the scanning unit;
A control unit that issues a laser beam projection command to the light projecting unit and controls scanning by the scanning unit;
A calculation unit that obtains the three-dimensional information of the measurement object based on the light projection timing of the laser beam given from the control unit and the light reception timing of the reflected laser beam given from the light receiving unit,
The calculation unit obtains a distance measurement origin position and an installation posture by a ground coordinate system from polar coordinate system position data obtained by measuring each position of laser light reflection points set in at least three places in a scanning range. Laser radar.   4. The laser radar according to claim 3, further comprising laser light reflectors arranged at laser light reflection points set at at least three points in the scanning range.

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