JP2009085920A - Vehicular laser radar device and dirt determination method for vehicular laser radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular laser radar device capable of reducing erroneous determination of contamination of a light transmission window during rain and continuing vehicle control depending on measurement of a distance between vehicles.
When a light receiving element 6 receives laser light reflected and scattered from the light transmission window 2 due to dirt adhering to the outside of the light transmission window 2, the amount of light received is equal to or greater than a threshold value. When it is determined that it is raining, dirt determination means for determining whether or not the radar device is contaminated with an allowable amount or more, rain determination means for determining whether or not it is raining, a threshold value is set. Threshold value changing means for changing to a higher value.
[Selection] Figure 1

Description

  The present invention relates to a vehicular laser radar apparatus that measures a distance from a front obstacle, and more particularly to a technique for detecting dirt adhering to a light transmission window of a laser radar apparatus.

As a conventional laser radar device, scattered light from a light transmission window of laser light emitted from a laser light emitting unit is received by a light receiving unit, and when the amount of scattered light received exceeds a certain threshold value, the light transmission window A technique is disclosed in which it is determined that more than an allowable amount of dirt has adhered to the driver, and the driver is notified of dirt on the light transmission window (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 9-211108

  However, in the above prior art, the amount of received scattered light increases due to the attachment of raindrops to the light transmission window during rain, so even if the actual contamination of the light transmission window is less than the allowable amount, the light reception amount May exceed the threshold value, and erroneous determination that the light transmission window is dirty occurs. For this reason, there existed a problem that the vehicle control depending on the measurement of the inter-vehicle distance such as inter-vehicle distance control was forced to be stopped.

  The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to reduce erroneous determination of contamination of a light transmission window during rain and to continue vehicle control that depends on measurement of the distance between vehicles. Another object of the present invention is to provide a vehicular laser radar device and a contamination determination method for the vehicular laser radar device.

  In order to achieve the above-described object, in the present invention, when the amount of received laser light reflected and scattered from the light transmission window is equal to or greater than a threshold value, it is determined that dirt exceeding an allowable amount has adhered to the radar device. In the contamination determination method for a vehicle laser radar apparatus, the contamination determination is performed by changing the threshold value to a higher value when it is raining than when it is not raining.

  Therefore, in the present invention, since the threshold value is changed to a higher value during the rain, even if the amount of scattered light received increases due to the attachment of raindrops to the light transmission window, the radar apparatus is allowed. It becomes difficult to determine that dirt exceeding the capacity has adhered, and it is possible to reduce erroneous judgment of dirt on the light transmission window during rainfall. As a result, even when it is raining, vehicle control such as inter-vehicle distance control that depends on measurement of inter-vehicle distance can be continued.

  Hereinafter, the best mode for carrying out the present invention will be described based on Examples 1 to 3.

FIG. 1 is a diagram illustrating the configuration of the vehicle laser radar device according to the first embodiment.
The laser radar device 1 includes a light transmission window 2, a light receiving window 3, a laser light emitting element 4, a drive circuit 5, a light receiving element 6, an amplification circuit 7, a reflection mirror 20, a stepping motor 21, a motor drive circuit 22, a scattering plate 30, and a CPU 12. It has.

  The laser light emitting element 4 sends out laser light in the near infrared wavelength region. The drive circuit 5 drives the laser light emitting element 4. The light receiving element 6 is an optical system that scatters the laser light to be scanned, and receives the laser reflected light that is returned from the laser light transmitted from the laser light emitting element 4 reflected by a preceding vehicle or the like. In the first embodiment, a photodiode that converts received light intensity of received laser light into a voltage is used as the light receiving element 6. The amplifier circuit 7 amplifies a minute light reception signal (voltage) from the light receiving element 6.

  The reflection mirror 20 rotates in order to scan the laser beam St0 transmitted from the laser light emitting element 4 as n beams within a predetermined angular range. The stepping motor 21 rotates the reflection mirror 20 with a predetermined angular resolution (n). The motor drive circuit 22 drives the stepping motor 21. The scattering plate 30 reflects and scatters the laser beam Stn transmitted to the end when the laser beam is scanned, and hits the entire surface of the light transmission window 2.

  The CPU 12 controls the drive circuit 5, the amplifier circuit 7 and the motor drive circuit 22 to transmit laser light from the laser light emitting element 4, and calculate the distance and relative speed from the received light signal to the preceding vehicle. The possibility of a collision with the preceding vehicle is judged from these calculation results and the own vehicle speed calculated from the vehicle speed signal input via the CAN communication line 31, and there is a possibility of distance data and collision to the outside. Alarm signal is output.

  Data output from the CPU 12 is transmitted to a display device (not shown), and the display device displays an inter-vehicle distance and a dirt state of the light transmission window 2 with an indicator, and outputs an alarm with an alarm.

  A light receiving lens is incorporated in the light receiving window 3, and light condensed by this lens is input to the light receiving element 6. Although not shown, a light transmission lens is provided in front of the laser light emitting element 4, and the laser light St0 transmitted from the laser light emitting element 4 is converged to a very thin beam. In the case of a scanning laser radar, the width of one laser beam is about 0.1 to 1 deg, but this value can be arbitrarily set in design.

FIG. 2 is a diagram illustrating the operation of the laser radar device 1 according to the first embodiment.
The CPU 12 operates the drive circuit 5 of the laser light emitting element 4 and the stepping motor drive circuit (hereinafter referred to as “motor drive circuit”) 22 at a predetermined timing to send the laser light from the laser light emitting element 4. The transmitted laser beam St0 is reflected by the reflection mirror 20 and is transmitted from the light transmission window 2 to the front outside. At this time, since the stepping motor 21 is configured to rotate in synchronization with the light emission of the laser light emitting element 4 by the action of the motor drive circuit 22, the laser beam St0 from the laser light emitting element 4 is sequentially supplied to St1, St2, St3, ..., n beams such as Stn-1 and Stn are sent at a predetermined angle toward the front of the vehicle. The radar repeats the above operation at a predetermined cycle.

  Here, the beam Stn scanned last among these laser beams is set so as to be incident on the internal scattering plate 30 without going directly to the outside from the light transmission window 2. The laser beam incident on the scattering plate 30 is reflected and scattered and spreads over the entire light transmission window 2 to be emitted. Normally, when there is no dirt attached to the light transmission window 2, the scattered laser beam passes through the light transmission window 2 and is transmitted forward.

  However, after a certain amount of time has passed, dirt 2d due to mud, sand, or the like adheres to the front surface of the laser radar device 1 and hinders transmission of the laser beam. The laser beam reflected and scattered by the scattering plate 30 strikes the dirt 2 d and is reflected and enters the light receiving element 6. The light input to the light receiving element 6 is amplified by the amplifier circuit 7 and input to the CPU 12. The greater the degree of contamination, the lower the transmittance of the laser beam and the greater the ratio of reflection / scattering. The detection signal level of the light receiving element 6 amplified in step 7 is compared to determine the presence or absence of contamination.

  Based on the wiper switch signal output from the wiper switch 32, this threshold value is changed to a higher value when it is determined that it is raining than when it is determined that it is not raining. . The wiper switch 32 is a switch for operating a wiper (not shown), and is turned ON / OFF by a driver. When the wiper switch signal is OFF, the wiper is inactive, and when the wiper switch signal is ON, the wiper is activated.

  The beam from the first beam St0 to the n-1th beam is a beam used for measuring the distance from the normal preceding vehicle, but the nth beam Stn is a dedicated beam for detecting dirt in the light transmission window 2, Internally to the CPU 12, as shown in FIG. 3, following the distance measurement data step 1 to step n-1, the nth data is treated as dirt detection data.

  FIG. 4 shows an example of a data format handled internally by the CPU 12. Each step from step 1 to step n is composed of 12-bit data D1 to Dn. The least significant bit b0 is a flag that is set when the laser light emitting element 4 is transmitting light, and is set to [1] when light transmission is on and [0] when light transmission is off. Ten bits from bit 1 to bit 10 are distance measurement data, and indicate the distance measured from the time until the laser beam is reflected by the front object and returned. The most significant bit b11 is a flag indicating whether or not there is a reflective target ahead, and [1] is set when the target is detected. Further, b11 shares the dirt detection flag of the light transmission window 2, and when the received signal level exceeds a predetermined threshold as described above, [1] is set as being dirty.

  In this example, [1] is set in the most significant bit b11 of the data D4, D5, Dn-4, and Dn-3, indicating that a target exists ahead in these angular directions. Although the distance to the target is not shown, it is stored in b1 to b10. Furthermore, [1] is also set in the most significant bit b11 of the nth data Dn. However, since Dn is dedicated data for detecting the dirt of the light transmission window 2, this is not because the forward target is detected. In other words, it shows that dirt is attached to the front surface of the light transmission window 2. When dirt on the light transmission window 2 is detected in this way, the CPU 12 sends data indicating “radar dirt” to the display device, etc., and informs the driver by means such as lighting an indicator, and measures the distance between the vehicles. When the vehicle control such as the inter-vehicle distance control depending on the vehicle is executed, the vehicle control is released. As a result, the driver can recognize the deterioration of the radar performance and prompt the cleaning, and the deterioration of the controllability of the vehicle control due to the deterioration of the radar performance can be prevented.

[Dirt judgment control processing]
FIG. 5 is a flowchart showing a stain determination control process executed by the CPU 12 according to the first embodiment. Each step will be described below.

  In step S1, the detection signal level (voltage value) of the light receiving element 6 amplified by the amplifier circuit 7 is read as the reflection level from the sensor front window (light transmission window 2), and the process proceeds to step S2.

  In step S2, whether or not it is raining is determined based on whether or not the wiper switch signal is ON (rainfall determining means). If YES, the process proceeds to step S3. If NO, the process proceeds to step S5.

  In step S3, it is determined whether or not an elapsed time after the wiper switch signal changes from ON to OFF is within a predetermined time (for example, 30 seconds). If YES, the process proceeds to step S4. If NO, the process proceeds to step S5.

  In step S4, a value obtained by adding a predetermined value to the normal dirt detection threshold is selected as the dirt detection threshold, and the process proceeds to step S6 (threshold changing means).

  In step S5, a normal dirt detection threshold value is selected, and the process proceeds to step S6.

  In step S6, the detection signal level of the light receiving element 6 read in step S1 is compared with the contamination detection threshold value selected in step S4 or step S5 to determine the contamination, and the process proceeds to return (dirt determination means). ).

  When the detection signal level is equal to or higher than the dirt detection threshold, the CPU 12 determines that dirt exceeding the allowable amount is attached to the radar device, and controls the vehicle such as an alarm to the driver and an inter-vehicle distance control depending on the radar. To stop.

Next, the operation will be described.
[Dirt judgment action]
When the weather is fine, in the flowchart of FIG. 5, the flow proceeds from step S 1 → step S 2 → step S 3 → step S 5, and the normal dirt detection threshold value is compared with the detection signal level of the light receiving element 6 to determine the dirt. I do.

  For this reason, it is possible to detect the contamination of the light transmission window 2 with an inexpensive configuration while eliminating the need for the contamination detection dedicated transmission / reception element and peripheral circuits such as driving and amplification. In addition, since the dirt of the light transmission window 2 can be detected during a series of distance measurement processing, the logic for controlling the detection circuit dedicated to the dirt detection is not necessary, and the dirt detection response without disturbing the normal distance measurement. Can increase the sex.

  When it rains, the flow proceeds from step S1 to step S2 to step S4 to step S6, and contamination determination is performed by comparing the threshold value higher than the normal contamination detection threshold value with the detection signal level of the light receiving element 6. .

  For this reason, even when the amount of scattered light received increases due to the attachment of raindrops to the light transmission window 2, it is difficult to determine that more than an allowable amount of dirt has adhered to the radar device. It is possible to reduce erroneous determination of dirt on the window 2. As a result, even when it is raining, vehicle control such as inter-vehicle distance control that depends on measurement of inter-vehicle distance can be continued.

  If the rain stops while driving, or if you enter underpass or tunnel during the rain, step S1 → step S2 → step S3 → step S1 → step S2 → step S3 → The flow proceeds from step S4 to step S6, and the dirt determination is performed based on a threshold value higher than the normal dirt detection threshold value until 30 seconds elapse after the wiper switch is turned on.

  That is, when there is a possibility that raindrops are attached to the light transmission window 2 even when the weather changes from rainy weather, or when there is a high possibility of returning to the rainy state immediately, the stain detection threshold set higher than normal is set. By maintaining the value, it is possible to more reliably reduce erroneous contamination determination of the light transmission window 2.

Next, the effect will be described.
In the vehicular laser radar apparatus 1 according to the first embodiment, the following effects can be obtained.

  (1) When the light receiving element 6 receives laser light reflected and scattered from the light transmission window 2 due to dirt adhering to the outside of the light transmission window 2, the CPU 12 receives the amount of light that is equal to or greater than a threshold value. , Dirt determination means (step S6) for determining that dirt exceeding the allowable amount has adhered to the radar device, rainfall determination means (step S2) for determining whether or not it is raining, A threshold value changing means (step S4) for changing the threshold value to a higher value. As a result, it is possible to reduce erroneous determination of contamination of the light transmission window 2 during rain, and as a result, vehicle control such as inter-vehicle distance control that depends on measurement of inter-vehicle distance can be continued even during rain. it can.

  (2) The rain judging means (step S2) judges that it is raining when the vehicle wiper is in operation, so whether it is raining accurately and inexpensively without adding a sensor for detecting rain. It can be determined whether or not.

  (3) The threshold value changing means (step S4) is changed until a predetermined time (for example, 30 seconds) elapses when switching from the judgment that it is raining to the judgment that it is not raining. In order to maintain the threshold value, erroneous determination of contamination of the light transmission window 2 can be more reliably reduced.

  (4) The scattering plate 30 that scatters the laser beam to be scanned is placed at the extreme end in the left-right direction inside the laser radar device 1 at a position where the scattered laser beam irradiates and transmits the light transmission window 2 from the inside. When the light receiving element 6 receives the laser light reflected and scattered from the light transmission window 2 due to dirt attached to the outside of the light transmission window 2, when the light reception amount is equal to or greater than the threshold value, the radar device In the vehicular laser radar apparatus 1 for determining whether or not dirt is more than allowable, the dirt is determined by changing the threshold value to a higher value when it is raining than when it is not raining. Make a decision. As a result, it is possible to reduce erroneous determination of contamination of the light transmission window 2 during rain, and as a result, vehicle control such as inter-vehicle distance control that depends on measurement of inter-vehicle distance can be continued even during rain. it can.

Example 2 is an example in which it is determined whether or not it is raining based on the driving voltage of the wiper.
FIG. 6 is a diagram illustrating a configuration of the vehicle laser radar device 1 according to the second embodiment. The second embodiment is different from the first embodiment in that a wiper drive voltage is input to the CPU 12 instead of the wiper switch signal. The wiper drive voltage is a voltage between terminals of a wiper motor 33 that drives a wiper (not shown), is measured by the voltage sensor 34, and is input to the CPU 12 via the CAN communication line 31.
Other configurations are the same as those in the first embodiment, and thus description thereof is omitted.

[Dirt judgment control processing]
FIG. 7 is a flowchart showing the flow of the dirt determination control process executed by the CPU 12 according to the second embodiment. Each step will be described below. In addition, the same step number is attached | subjected to the step which performs the same process as Example 1 shown in FIG. 5, and description is abbreviate | omitted.

  In step S12, whether or not it is raining is determined by whether or not the voltage of the wiper switch is at a high level (for example, 9 V or more). If YES, the process proceeds to step S4. If NO, the process proceeds to step S13.

  In step S13, it is determined whether or not the elapsed time after the wiper switch voltage changes from the high level to the low level is within a predetermined time (for example, 30 seconds). If YES, the process proceeds to step S4. If NO, the process proceeds to step S5.

Next, the operation will be described.
[Dirt judgment action]
When the weather is fine, the flow proceeds from step S1 to step S12 to step S13 to step S5 in the flowchart of FIG. 7, and the normal contamination detection threshold is compared with the detection signal level of the light receiving element 6 to determine the contamination. I do.

  For this reason, it is possible to detect the contamination of the light transmission window 2 with an inexpensive configuration while eliminating the need for the contamination detection dedicated transmission / reception element and peripheral circuits such as driving and amplification. In addition, since the dirt of the light transmission window 2 can be detected during a series of distance measurement processing, the logic for controlling the detection circuit dedicated to the dirt detection is not necessary, and the dirt detection response without disturbing the normal distance measurement. Can increase the sex.

  When it rains, the flow proceeds from step S1 to step S12 to step S4 to step S6, and contamination determination is performed by comparing the threshold value higher than the normal contamination detection threshold value with the detection signal level of the light receiving element 6. .

  For this reason, even when the amount of scattered light received increases due to the attachment of raindrops to the light transmission window 2, it is difficult to determine that more than an allowable amount of dirt has adhered to the radar device. It is possible to reduce erroneous determination of dirt on the window 2. As a result, even when it is raining, vehicle control such as inter-vehicle distance control that depends on measurement of inter-vehicle distance can be continued.

  If it stops raining while driving, or if you enter underpass or tunnel during raining, step S1 → step S12 → step S6 → from step S1 → step S12 → step S13 → The flow proceeds from step S4 to step S6. Based on a threshold higher than the normal contamination detection threshold until 30 seconds elapse after the wiper voltage changes from the high level to the low level. Check the dirt.

  That is, when there is a possibility that raindrops are attached to the light transmission window 2 even when the weather changes from rainy weather, or when there is a high possibility of returning to the rainy state immediately, the stain detection threshold set higher than normal is set. By maintaining the value, it is possible to more reliably reduce erroneous contamination determination of the light transmission window 2.

  Therefore, the vehicular laser radar device 1 according to the second embodiment can obtain the same effects as the effects (1), (2), and (4) of the first embodiment.

Example 3 is an example of determining whether or not it is raining based on the output voltage of the raindrop sensor.
FIG. 8 is a diagram illustrating a configuration of the vehicle laser radar device 1 according to the third embodiment. In the third embodiment, the output voltage of the raindrop sensor 35 is input to the CPU 12 instead of the wiper switch signal. And different. The raindrop sensor output voltage is measured by the voltage sensor 36 and input to the CPU 12 via the CAN communication line 31.
Other configurations are the same as those in the first embodiment, and thus description thereof is omitted.

[Dirt judgment control processing]
FIG. 9 is a flowchart showing the flow of the dirt determination control process executed by the CPU 12 of the third embodiment. Each step will be described below. In addition, the same step number is attached | subjected to the step which performs the same process as Example 1 shown in FIG. 5, and description is abbreviate | omitted.

  In step S22, whether or not it is raining is determined by whether or not the output voltage of the raindrop sensor 35 exceeds a predetermined threshold value. If YES, the process proceeds to step S4. If NO, the process proceeds to step S23.

  In step S23, it is determined whether the elapsed time after the output voltage of the raindrop sensor changes from a state exceeding the threshold to a state below the threshold is within a predetermined time (for example, 30 seconds). To do. If YES, the process proceeds to step S4. If NO, the process proceeds to step S5.

Next, the operation will be described.
[Dirt judgment action]
When the weather is fine, in the flowchart of FIG. 9, the flow proceeds from step S 1 → step S 22 → step S 23 → step S 5, and the normal dirt detection threshold and the detection signal level of the light receiving element 6 are compared to determine the dirt. I do.

  For this reason, it is possible to detect the contamination of the light transmission window 2 with an inexpensive configuration while eliminating the need for the contamination detection dedicated transmission / reception element and peripheral circuits such as driving and amplification. In addition, since the dirt of the light transmission window 2 can be detected during a series of distance measurement processing, the logic for controlling the detection circuit dedicated to the dirt detection is not necessary, and the dirt detection response without disturbing the normal distance measurement. Can increase the sex.

  When it rains, the flow proceeds from step S1 to step S22 to step S4 to step S6, and contamination determination is performed by comparing the threshold value higher than the normal contamination detection threshold value with the detection signal level of the light receiving element 6. .

  For this reason, even when the amount of scattered light received increases due to the attachment of raindrops to the light transmission window 2, it is difficult to determine that more than an allowable amount of dirt has adhered to the radar device. It is possible to reduce erroneous determination of dirt on the window 2. As a result, even when it is raining, vehicle control such as inter-vehicle distance control that depends on measurement of inter-vehicle distance can be continued.

  If it stops raining while driving, or if you enter underpass or tunnel while it is raining, from step S1 → step S22 → step S4 → step S6, proceed to step S1 → step S22 → step S23 → The flow proceeds from step S4 to step S6, and during the period from when the raindrop sensor output voltage changes from a state exceeding the predetermined value to a state below the predetermined value until 30 seconds elapses, the normal contamination detection threshold is reached. The stain determination is performed based on a threshold value higher than the value.

  That is, when there is a possibility that raindrops are attached to the light transmission window 2 even when the weather changes from rainy weather, or when there is a high possibility of returning to the rainy state immediately, the stain detection threshold set higher than normal is set. By maintaining the value, it is possible to more reliably reduce erroneous contamination determination of the light transmission window 2.

Next, the effect will be described.
In addition to the effects (1), (3), and (4) of the first embodiment, the vehicle laser radar device 1 of the third embodiment has the following effects.

  (5) The rain determination means (step S22) determines that the raindrop sensor 35 is raining when the detection level of the raindrop sensor 35 exceeds a predetermined value. It is possible to determine whether or not it is raining at low cost and accurately using a raindrop sensor 35 that is generally mounted on the vehicle as a sensor.

(Other examples)
Although the best mode for carrying out the present invention has been described with reference to the respective embodiments based on the drawings, the specific configuration of the present invention is not limited to those shown in the respective embodiments. Any design changes that do not change the gist of the present invention are included in the present invention.

For example, in the embodiment, the wiper switch signal, the wiper drive signal, or the raindrop sensor output voltage signal is input to the CPU 12 via the CAN communication line, but the wiper switch signal, the wiper drive signal, or the raindrop sensor output voltage signal is linearly input. It is good also as a structure input to CPU12.
In the embodiment, the configuration using the scattering plate is shown as the optical system for scattering the laser beam to be scanned, but an optical fiber may be used.

1 is a diagram illustrating a configuration of a vehicle laser radar device 1 according to a first embodiment. FIG. 3 is a diagram illustrating an operation of the laser radar device 1 according to the first embodiment. FIG. 6 is a diagram showing that a dirt display-dedicated data step n is included after a series of distance measurement data steps 1 to n−1 in one distance measurement cycle of the first embodiment. It is a figure which shows an example of the data format handled internally by CPU12. 3 is a flowchart illustrating a flow of a dirt determination control process executed by a CPU 12 according to the first embodiment. It is a figure which shows the structure of the laser radar apparatus 1 for vehicles of Example 2. FIG. 6 is a flowchart illustrating a flow of a dirt determination control process executed by a CPU 12 according to the second embodiment. FIG. 5 is a diagram illustrating a configuration of a vehicle laser radar device 1 according to a third embodiment. 12 is a flowchart illustrating a flow of a dirt determination control process executed by a CPU 12 according to a third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser radar apparatus 2 Light transmission window 3 Light reception window 4 Laser light emitting element 5 Driving circuit 6 Light receiving element 7 Amplifying circuit 20 Reflecting mirror 21 Stepping motor 22 Stepping motor driving circuit 30 Scattering plate 31 CAN communication line 32 Wiper switch 33 Wiper motor 34 Voltage Sensor 35 Raindrop sensor 36 Voltage sensor

Claims (5)

In a laser radar apparatus for a vehicle that irradiates laser light while scanning a predetermined angle range on the left and right in front of the camera at every predetermined angle step, and measures the distance from the irradiation until the reflected light is received to measure the distance from the front object. ,
An optical system that scatters the laser beam to be scanned is provided at the extreme end in either of the left and right directions inside the apparatus at a position where the scattered laser beam irradiates and transmits the light transmission window from the inside.
When the light receiving element receives laser light reflected and scattered from the light transmission window to the inside due to dirt adhered to the outside of the light transmission window, when the light reception amount is equal to or greater than a threshold value, the radar device exceeds the allowable amount. A dirt determination means for determining that dirt is attached;
Rain judging means for judging whether or not it is raining,
A threshold value changing means for changing the threshold value to a higher value when it is determined that it is raining;
A vehicular laser radar device. In the vehicle radar laser device according to claim 1,
The vehicle laser radar device according to claim 1, wherein the rain determining means determines that it is raining when the vehicle wiper is in operation. The vehicle laser radar device according to claim 1,
The vehicle laser radar device according to claim 1, wherein the rain determining means determines that it is raining when the detection level of the raindrop sensor exceeds a predetermined value. In the laser radar device according to any one of claims 1 to 3,
The threshold value changing means changes the threshold value until a predetermined time elapses when the judgment result of the rain judgment means is switched from judgment that it is raining to judgment that it is not raining. A vehicle laser radar device characterized by maintaining the above. An optical system that scatters the laser beam to be scanned is provided at the extreme end in the left-right direction inside the laser radar device at a position where the scattered laser beam irradiates and transmits the light transmission window from the inside. When the light receiving element receives laser light reflected and scattered from the light transmission window to the inside due to the attached dirt, if the received light quantity is greater than or equal to the threshold value, it is determined that more than an allowable amount of dirt has adhered to the radar device. In the method for determining contamination of a vehicle laser radar device,
A dirt determination method for a vehicular laser radar apparatus, characterized in that when it is raining, the dirt is determined by changing the threshold value to a higher value than when it is not raining.

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