JP2010019621A - Laser radar and method for determining measuring condition of same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser radar and a method for determining the measuring conditions of the laser radar capable of reliably determining measuring conditions such as variations in the mounting attitude of the laser radar and reductions in the rate of transmission through space of a laser beam due to weather without causing increases in system costs and in failure rate. <P>SOLUTION: The laser radar 1 includes a light projection part 2; a scanning part 3 for scanning a laser beam LT from the light projection part 2; a light receiving part 4 for receiving a reflected laser beam LR from an object to be measured; a control part 5 for controlling projection timing and the scanning by the scanning part 3; an operation part 6 for acquiring three-dimensional measurement information on the basis of the projection timing of the laser beam LT and the reception timing of the reflected laser beam LR; and a laser beam reflector 7 for determination installed at one location in a monitorable region E. The operation part 6 determines the installation conditions of the laser radar 1 and the conditions of propagation of the laser beam through space on the basis of a threshold value of the number of measuring points and a threshold value of reflection intensity acquired from initial data of the laser beam reflector 7 for determination and the number of measuring points and reflection intensity in measurement data of the laser beam reflector 7 for determination acquired during the measurement. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser radar measurement status determination method and a laser radar used to determine a change in the measurement status of a laser radar that monitors, for example, the presence or absence of a person in a crossing or an intersection.

  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 back 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 laser beam emitted from the control unit is projected. The three-dimensional data to be measured is acquired based on the timing and the light reception timing of the reflected laser beam given from the light receiving unit.

  In such a laser radar, for example, when it is installed at a level crossing, a reflection means is provided in a monitoring area set in the level crossing, and a reflection signal from the reflection means and known data regarding the position and distance of the reflection means. Based on the above, the scanning range and the light projecting / receiving performance are checked to detect the abnormality of the device itself including the scanning unit, the light projecting unit, and the light receiving unit (see, for example, Patent Documents 1 and 2). .

Although this laser radar can detect anomalies that have occurred in the device itself, it can detect changes in measurement conditions caused by external loads, such as a shift in the mounting posture and a decrease in the spatial propagation rate of laser light due to the weather. Cannot be detected.
Therefore, with regard to the mounting posture of the laser radar, a countermeasure for detecting a change in posture by installing a measuring instrument such as an inclinometer or a gyro sensor on the laser radar has been studied. Countermeasures are being considered in which measuring instruments such as meters are installed in the monitoring area to detect changes.
JP2003-11824 JP 2005-233615 A

  However, as described above, when using a measuring instrument such as an inclinometer, a gyro sensor, or a visibility meter to detect a change in the mounting posture of the laser radar or a change in the spatial propagation rate of the laser light, To solve these problems, the system that detects the measurement status becomes complicated, which increases the cost and the failure rate of the entire system may increase. Has become a conventional problem.

  The present invention has been made by paying attention to the above-described conventional problems, and does not increase the system cost, and does not increase the failure rate of the entire system. It is an object of the present invention to provide a laser radar measurement status determination method and a laser radar capable of reliably determining a change in measurement status caused by an external load such as a decrease in light spatial propagation rate.

  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 method for determining the measurement status of a laser radar that acquires three-dimensional information of a measurement object, wherein at least one position in a measurable region of the laser radar installed at a predetermined position with a predetermined posture is a laser beam reflection point for determination 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 for determination, the position and measurement of the laser beam reflection point for determination are measured. The number of points and reflection intensity are registered as initial data, and the number of measurement points and reflection intensity are extracted from the measurement data at the position of the determination laser light reflection point obtained during measurement by the laser radar. Then, the number of measurement points and the reflection intensity are compared with the measurement point threshold value and the reflection intensity threshold value obtained from the initial data of the determination laser beam reflection point, respectively. The configuration is characterized in that the propagation status is determined, and the configuration of the laser radar measurement status determination method is used as a means for solving the above-described conventional problems.

In the laser radar measurement status determination method according to claim 2 of the present invention, a laser beam reflector disposed at least at one position in a measurable region of the laser radar installed at a predetermined position in a predetermined posture is used as a laser beam. The reflection point is used.
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 A calculation unit that obtains the three-dimensional information of the measurement object based on the light projection timing of the laser beam and the light reception timing of the reflected laser beam given from the light receiving unit, and a determination laser light reflector installed in at least one place in the measurable region The calculation unit includes a measurement point threshold value and a reflection intensity threshold value obtained from initial data at the position of the determination laser light reflector obtained at the time of initial setting, and the measurement point obtained during measurement. Comparing the number of measurement points and reflection intensity in the measurement data at the position of the regular laser light reflector, respectively, it is characterized in that it is configured to determine the installation status of the laser radar and the spatial propagation status of the laser light, The configuration of the laser radar is used as a means for solving the above-described conventional problems.

In the laser radar measurement status determination method and the 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 laser marker, and the signal waveform is pulsed or phase-modulated. A sinusoidal laser beam is used.
In the laser radar measurement status determination method and laser radar according to the present invention, at least one location in the measurable region of the laser radar installed at a predetermined position and in a predetermined posture is determined as a laser beam reflection point for determination (at least at one location). If a laser beam is projected from the laser radar, the initial data of the position of the laser beam reflection point is registered, and this laser radar performs the measurement, Based on the measurement data obtained in step (1), it is possible to reliably determine changes in the measurement status due to external loads such as deviations in the mounting posture of the laser radar and a decrease in laser light spatial propagation rate due to weather. It is not necessary to use measuring instruments such as an inclinometer, a gyro sensor, or a visibility meter just by determining the laser light reflection point for determination (installing a laser light reflector for determination). Since, and thus may contribute to the failure rate reduced overall system cost containment and systems.

  In the laser radar measurement status determination method and the laser radar according to the present invention, the above-described configuration is adopted. Therefore, an increase in system cost and an increase in the failure rate of the entire system are suppressed, and a deviation in the mounting posture of the laser radar and weather conditions are suppressed. As a result, it is possible to reliably determine a change in measurement state caused by an external load such as a decrease in the spatial propagation rate of laser light due to the laser beam.

Hereinafter, a laser radar measurement status determination method and a laser radar according to the present invention will be described with reference to the drawings.
1 to 3 show an embodiment of a laser radar measurement status determination method according to the present invention. In this embodiment, the laser radar measurement status determination method according to the present invention is installed at a railroad crossing for monitoring purposes. A case where the present invention is applied to a laser 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 determination laser light reflector (determination laser light reflection point) 7 installed in at least one location of a monitoring region E that is a measurable region are provided.

At this time, the size, shape, and material of the determination 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. Further, if there is an existing area that can reflect the laser beam LT in the area set as the monitoring area E, it may be adopted as the laser beam reflection point.
In the calculation unit 6, the measurement point threshold value and the reflection intensity threshold value obtained from the initial data at the position of the determination laser light reflector 7 acquired at the initial setting, and the measurement at the position of the determination laser light reflector 7 acquired during the measurement. The number of measurement points and the reflection intensity in the data are respectively compared to determine the installation status and the spatial propagation status of the laser beams LT and LR.

  In this embodiment, the predetermined integrated value of the number of measurement points at the position of the determination laser light reflector 7 acquired during measurement is 50 with respect to the measurement point threshold obtained from the initial data at the position of the determination laser light reflector 7. % Is maintained for a certain period of time as a criterion for the installation status of the calculation unit 6, and when the criterion is exceeded, the attitude of the laser radar 1 due to the looseness of the fixture or the inclination of the support column Is determined to have changed.

  Here, as shown in FIG. 2, the apparent angle range of the determination laser light reflector 7 varies depending on the distance L from the laser radar 1. For example, when the size of the determination laser light reflector 7 is 0.2 m wide × 0.3 m long and the installation range is 7 to 20 m, the horizontal angle when the distance L from the laser radar 1 is 7 m. When θh is 1.64 °, vertical angle θv is 2.45 °, and distance L from laser radar 1 is 20 m, horizontal angle θh is 0.57 ° and vertical angle θv is 0.86 °. .

  On the other hand, the angle change allowable value of the laser radar 1 determined to surely detect a crossing obstacle (an object having a width of 1 m, a height of 1 m, and a depth of 1 m) as a detection target is 1.9 ° in the horizontal direction and vertical. Assuming that the direction is 1.3 °, when a posture change corresponding to an allowable value occurs in the horizontal direction or the vertical direction, as shown in FIG. 3, the vertical direction measurement is performed when the distance L from the laser radar 1 is 7 m. When the predetermined integrated value of the score is 47% with respect to the threshold value of the measuring point and the distance L from the laser radar 1 is 7 m, or when the distance L from the laser radar 1 is 20 m. Both the predetermined integrated value of the horizontal measurement points and the predetermined integrated value of the vertical measurement points are 0% with respect to the measurement point threshold value. Therefore, by setting the determination criterion for the posture change to 50%, it is possible to determine the angle change at which the crossing obstacle cannot be detected.

  On the other hand, in the state where the railroad crossing alarm is activated, the reflection intensity average value in the measurement data at the position of the determination laser light reflector 7 acquired during measurement is based on the initial data at the position of the determination laser light reflector 7. The case where the state of 40% or less with respect to the required reflection intensity threshold value continues for a certain period of time is used as a criterion for the spatial propagation state of the laser beams LT and LR, and when this criterion is exceeded, rain or snow It is determined that the spatial propagation rate of the laser beams LT and LR is decreased due to fog or fog.

Here, the criteria for determining the spatial propagation rate change of the laser beams LT and LR are determined in consideration of the snow having a high reflection intensity, the passing vehicle having a color with a low reflection intensity, the size of the laser beam reflector 7 for determination, and the like. The
Therefore, a procedure for determining the measurement status when the laser radar 1 is installed at the railroad crossing will be described.
First, the determination laser light reflector 7 is installed in at least one place in the monitorable region E of the laser radar 1 installed in a predetermined position at a predetermined position.

Subsequently, based on the reflected laser beam LR that is scanned by the scanning unit 3 while projecting the laser beam LT from the light projecting unit 2 and reflected by at least one laser beam reflector 7, the laser for determination is used. The position of the light reflector 7, the number of measurement points, and the reflection intensity are registered as initial data.
Then, the operation of the laser radar 1 is started, and the number of measurement points is calculated from the measurement data at the position of the determination laser light reflector 7 obtained during the measurement performed by projecting the laser light LT from the light projecting unit 2 of the laser radar 1. And the reflection intensity is extracted.

  Next, the calculation unit 6 compares the number of measurement points and the reflection intensity with the measurement point threshold value and the reflection intensity threshold value obtained from the initial data of the laser light reflector 7 for determination, and the measurement point integrated value is measured. When it is lower than the score threshold, it is determined that there is a change in posture, and when the average reflection intensity is lower than the reflection intensity threshold, it is determined that the spatial propagation rate of the laser beams LT and LR is reduced.

When the calculation unit 6 determines that there is a change in the posture, the presence or absence of looseness in the fixture of the laser radar 1 and the inclination of the support column are investigated, and the spatial propagation rate of the laser beams LT and LR decreases. If it is determined that the laser beam is restored, the normal measurement state is restored as soon as the weather recovers and the spatial propagation rates of the laser beams LT and LR return to normal values.
Thus, in the laser radar measurement status determination method according to the above-described embodiment, the determination laser light reflector 7 is installed in at least one place in the monitorable region E of the laser radar 1 installed in a predetermined position at a predetermined position. Then, after projecting the laser beam LT from the laser radar 1 and registering the initial data of the position of the determination laser beam reflector 7, when the laser radar 1 performs the measurement, the measurement data acquired thereby Therefore, it is possible to reliably determine a change in measurement status caused by an external load such as a deviation in the mounting posture of the laser radar 1 or a decrease in the spatial propagation rate of the laser beam due to the weather. By simply installing the light reflector 7, there is no need to use measuring instruments such as inclinometers, gyroscopes, and visibility meters, thus reducing system costs and reducing the overall system failure rate. So that the can Kumishi.

In the above-described embodiment, the case where the laser radar measurement state determination method according to the present invention is applied to a laser radar installed for monitoring at a railroad crossing is described as an example. However, 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 at an intersection for monitoring.
In the above-described embodiment, the determination laser light reflector 7 that is a laser light reflection point is arranged at one place in the monitorable region E that is a measurable region of the laser radar 1. Instead, a plurality of determination laser light reflectors 7 (or determination laser light reflection points) that are laser light reflection points may be installed in the monitorable region E that is a measurable region.

It is a block diagram which shows one Embodiment of the measurement condition determination method of the laser radar which concerns on this invention. It is a figure explaining the apparent angle of the laser beam reflector for determination in the laser radar shown in FIG. It is a figure explaining the determination criteria of the attitude | position change in the calculating part based on the apparent angle of the laser beam reflector for determination shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser radar 2 Light projection part 3 Scanning part 4 Light-receiving part 5 Control part 6 Calculation part 7 Laser beam reflector for determination (laser beam reflection point for determination)
E Monitoring area (measurement area)
LR Reflected laser beam LT Projected laser beam

Claims (3)

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 A method for determining the measurement status of
Set at least one place in the measurable area of the laser radar set in a predetermined position at a predetermined position as a laser beam reflection point for determination,
Based on the reflected laser light that is scanned while projecting laser light from the laser radar and reflected by the judgment laser light reflection point, the position, the number of measurement points, and the reflection intensity of the judgment laser light reflection point Is registered as initial data,
Extracting the number of measurement points and reflection intensity from the measurement data at the position of the laser beam reflection point for determination obtained during the measurement of the laser radar
The number of measurement points and reflection intensity are compared with the measurement point threshold value and reflection intensity threshold value obtained from the initial data of the judgment laser light reflection point, respectively, and the installation status of the laser radar and the spatial propagation state of the laser light are compared. A method for determining the measurement status of a laser radar, characterized by: determining.   2. The laser radar measurement status determination method according to claim 1, wherein a laser light reflector disposed at least at one position in a measurable region of the laser radar installed at a predetermined position in a predetermined posture is used as a laser light reflection point. 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 acquires the three-dimensional information of the measurement target 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,
Provided with a laser light reflector for determination installed in at least one place in the measurable region,
In the calculation unit, a measurement point threshold value and a reflection intensity threshold value obtained from initial data at the position of the determination laser light reflector acquired at the time of initial setting, and measurement at the position of the determination laser light reflector acquired during measurement. A laser radar characterized by comparing the number of measurement points and reflection intensity in the data to determine the installation status of the laser radar and the spatial propagation status of the laser beam.

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