JP7583254B2 - Laser radar device - Google Patents

Description

The present invention relates to a laser radar device.

A scanning laser radar device has an irradiation unit that sequentially irradiates laser light at a predetermined angle, and a light receiving unit that receives the reflected light of the laser light, and is configured to determine whether an object (target object) such as a person or a car is located within the detection area based on the amount of light received by the light receiving unit (see, for example, Patent Document 1).

JP 2010-151788 A

The above-mentioned laser radar device is installed in a variety of environments, and there is a possibility that tiny objects (non-target objects) such as snow and dust that are not intended as detection targets may pass through the detection area. When the laser light directly hits these tiny objects (especially tiny objects passing near the laser radar device), the amount of reflected laser light increases. When such an event occurs, it is determined (falsely detected) that the above-mentioned target object is located within the detection area, which is an obstacle to improving the reliability of the laser radar device. Thus, there is still room for improvement in the configuration of the laser radar device in order to reduce the effects of the environment in which the laser radar device is installed and improve its reliability.

The present invention was made in consideration of the above problems, and its main objective is to provide a laser radar device that can reduce the effects of the environment in which the laser radar device is installed and improve reliability.

The following describes the means to solve the above problems.

First means: an irradiation unit (irradiation unit 21) that sequentially irradiates laser light at irradiation angles set for each predetermined angle;
A light receiving unit (light receiving unit 31) that receives reflected light, which is the laser light reflected by an object (object T);
A determination unit (a function of executing the processes of steps S101 to S104 and S201 to S204 in the control unit 12) that determines whether an object that reflected the laser light is located in a detection area (monitoring area DE) based on the light receiving state (received light amount, etc.) of the reflected light by the light receiving unit;
The control unit 12 is provided with a change unit (a switching function between irradiation patterns A and B) for changing the size of the irradiation cross section of the laser light irradiated from the irradiation unit to the detection area.

Laser light with a small irradiation cross-sectional size (beam diameter size) is advantageous in terms of increasing the sensitivity of detecting objects compared to laser light with a large irradiation cross-sectional size. However, for small-sized laser light, the amount of reflection of the laser light (the ratio of the amount of reflection to the amount of light of the irradiated laser light) is large not only when it is irradiated on large objects (target objects) such as people and cars, but also when it is irradiated on tiny objects (non-target objects) such as snow and dust, especially when it is irradiated on tiny objects passing near the laser radar device. For these reasons, when irradiating small-sized laser light, there is a higher possibility of detecting (falsely detecting) tiny objects that would not normally be included in the detection target, compared to when irradiating large-sized laser light.

On the other hand, larger laser light has lower sensitivity in detecting objects compared to smaller laser light. However, when a laser light is irradiated onto a large object (target object) such as a person or a car, the amount of reflection of the laser light (the ratio of the amount of reflection to the amount of light of the irradiated laser light) is sufficient, just like with small laser light, but the amount of reflection of the laser light (the ratio of the amount of reflection to the amount of light of the irradiated laser light) is reduced because part of the laser light irradiated onto a tiny object (non-target object) passes by the side of the tiny object. In other words, when a large laser light is irradiated, it is easier to suppress the above-mentioned false detection compared to when a small laser light is irradiated.

Therefore, as shown in the first means, if the size (cross-sectional area) of the laser light irradiated from the irradiation unit to the detection area can be changed, that is, to a small size that is expected to improve sensitivity or a large size that is expected to suppress false detection, it is possible to suppress false detection due to non-target objects while suppressing overlooking of target objects. This reduces the influence of the installation environment and appropriately improves the reliability of the laser radar device. In addition, even if a configuration is used in which multiple laser lights of different sizes are used in combination at all times, it is possible to suppress false detection as in the first means, but the power consumption of the laser radar device will increase significantly. In this regard, if the size of the irradiated laser light can be changed as shown in the first means, power consumption can be reduced compared to the above-mentioned type in which the laser lights are used in combination at all times.

The upper limit of the size of the laser light is preferably set so that the cross-sectional area of the irradiation section within the detection area is smaller than the area of the portion of the target object (e.g., a person or a car) that is expected to be irradiated with the laser light.

Incidentally, in this feature, the description "a change unit that changes the size of the laser light irradiated from the irradiation unit to the detection area" can also be changed to "a switching unit that switches the size of the laser light irradiated from the irradiation unit to the detection area between a relatively small first size and a relatively large second size."

Second means: A means for changing at least one of the luminance of the laser light and the judgment condition by the judgment unit when the size of the laser light is changed by the change unit.

If at least one of the brightness and the judgment conditions of the laser light is changed in accordance with the change in the size of the laser light, the above-mentioned erroneous detection can be suitably reduced. For example, if the brightness of the laser light is reduced when the size of the laser light is increased and the brightness of the laser light is increased when the size of the laser light is decreased, the amount of reflection when a large-sized laser light directly hits a minute object such as snow or dust will be smaller than the amount of reflection when a small-sized laser light directly hits the minute object. This suppresses erroneous detection while keeping the above-mentioned judgment conditions unchanged or with little change. Also, if the judgment conditions are made stricter when the size of the laser light is increased and the judgment conditions are relaxed when the size of the laser light is decreased, the judgment when a large-sized laser light directly hits a minute object such as snow or dust will be stricter than the judgment when a small-sized laser light directly hits the minute object. This suppresses erroneous detection while keeping the brightness of the laser light unchanged or with little change.

When changing the brightness of the laser light in conjunction with a size change, it is advisable to specify the brightness of the laser light for each size so that the amount of laser light (amount of irradiation) is the same or approximately the same for each size before and after the change.

Incidentally, the configuration shown in this characteristic can also be configured as follows: "When the size of the laser light is increased, the change unit performs at least one of a change to lower the luminance of the laser light and a change to make the judgment conditions by the judgment unit stricter, and when the size of the laser light is decreased, the change unit performs at least one of a change to increase the luminance of the laser light and a change to make the judgment conditions by the judgment unit more strict."

Third means: The change unit is configured to change the size of the laser light at least in the scanning direction (e.g., the horizontal direction) of the laser light.

By configuring the size of the laser light to change in the scanning direction, it becomes easier to increase the irradiation area, i.e. the amount of reflection from the target object, when a large-sized laser light is irradiated onto an object (target object) such as a person or car within the area. This is preferable in terms of preventing the target object from being overlooked.

Fourth means: The change unit is capable of changing the size of the laser light for each scanning cycle of the laser light.

As shown in the fourth method, by making it possible to change the size of the laser light for each scanning cycle and ensuring an opportunity to change the size, the effect of suppressing false detections due to size changes can be more effectively achieved.

When the size of the laser light is changed for each scanning cycle, the change can be made when the direction of irradiation of the laser light is facing away from the detection area, thereby mitigating the constraints on the responsiveness of the size change.

Fifth means: The size of the laser light includes a first size (irradiation pattern A) and a second size (irradiation pattern B) larger than the first size,
the determination unit is configured to determine that the object is located in the detection area when the light receiving state of the light receiving unit is in a specific state (amount of received light>threshold value) continuously at the same irradiation angle in a predetermined number of scanning cycles (e.g., five times),
The changer is configured to change the size of the laser light to the second size at least once among the predetermined number of consecutive scanning cycles.

According to the configuration shown in the fifth means, a laser beam is irradiated onto an object (target object) such as a person or a car located in the detection area, and a specific situation occurs continuously at the same irradiation angle. When the number of consecutive occurrences reaches a predetermined number, it is determined that the object is located in the detection area. In contrast, when a laser beam is irradiated onto a minute object (non-target object) such as snow passing through the detection area, and a specific situation occurs continuously at the same irradiation angle for the minute object, the size of the laser beam becomes the second size before the number of consecutive occurrences reaches the predetermined number, and the succession is interrupted. In other words, even if a specific situation occurs continuously for a minute object, the number of consecutive occurrences can be made less than the predetermined number. By intentionally excluding a minute object from detection in this way, erroneous detection caused by the minute object can be suitably suppressed.

Sixth means: The number of times that the size of the laser light becomes the second size during the predetermined number of scanning cycles is less than the number of times that the size of the laser light becomes the first size.

As described above, the sensitivity of object detection is second size < first size. Therefore, by making the number of times that the first size laser light is irradiated greater than the number of times that the second size laser light is irradiated, it is possible to suitably suppress a decrease in the sensitivity of object detection. For example, it is preferable to configure the device so that irradiation of the second size laser light is appropriately inserted while irradiation of the first size laser light is repeated.

Seventh means: the determination unit is configured to determine that the object is located in the detection area when the light receiving state of the light receiving unit is in a specific state (amount of received light > threshold) continuously at the same irradiation angle in a predetermined number of scanning cycles (e.g., five times),
The change section is configured to increase the size of the laser light, with one of the change conditions being that the light receiving section is in a specific light receiving state.

The configuration in which the size of the laser light is increased when the light receiving situation is a specific situation, i.e., when the laser light is being irradiated onto some object, is one of the change conditions, is preferable in terms of suppressing the occurrence of false detections and reduced sensitivity in object detection by focusing on the number of times that small-sized laser light is irradiated, i.e., minimizing the number of times that large-sized laser light is irradiated. For example, if a specific situation occurs consecutively, the size of the laser light may be increased each time a specific situation occurs.

Eighth means: The size of the laser light includes a first size (irradiation pattern A) and a second size (irradiation pattern B) larger than the first size,
the determination unit is configured to determine that the object is located in the detection area when the light receiving state of the light receiving unit is in a specific state (amount of received light>threshold value) continuously at the same irradiation angle in a predetermined number of scanning cycles (e.g., five times),
The change unit is configured to change the size of the laser light to the second size when the light receiving situation of the light receiving unit continuously reaches a specific situation (amount of received light > threshold value) at the same irradiation angle in a specific number of scanning cycles (two or more, for example four) that are less than the predetermined number of times.

In a configuration in which the size of the laser light is changed to the second size when a specific number of times occurs when a specific light receiving situation occurs consecutively, if the specific number is less than a predetermined number, the false detection described in the first means can be suitably suppressed. In addition, a configuration in which the size is changed to the second size when a specific situation occurs consecutively is preferable in terms of suppressing the number of times that small-sized laser light is emitted unnecessarily. In other words, it is advantageous in suppressing the occurrence of false detection and a decrease in the sensitivity of object detection.

Ninth means: If the light receiving condition of the light receiving unit does not become the specific condition at the same irradiation angle during a scanning cycle in which the size of the laser light is changed to the second size by the change unit, the size of the laser light in the next scanning cycle is changed to the first size.

As shown in the eighth means, if the size of the laser light is changed to the second size before the specific number of times is reached to avoid reaching the specific number of times, the size is quickly returned to the first size after the avoidance, thereby minimizing the decrease in sensitivity of object detection.

The detection area is divided into a plurality of individual areas (areas DEL, DEM, DER) in the scanning direction of the laser light,
The change unit is capable of changing the size of the laser light for each of the individual areas.

As shown in this method, by dividing the detection area into multiple individual areas and making it possible to change the size of the laser light for each individual area, it is possible to maximize the opportunities for small-sized laser light to be emitted.

11. The irradiation unit includes a plurality of (e.g., three) light emitters (laser diodes 22a, 22b, and 22c),
The change unit is configured to change the size of the laser light by changing the number of light-emitting elements that are to be light-emitting objects among the plurality of light-emitting elements.

By changing the number of light emitters that are the targets of light emission among multiple light emitters, the size of the laser light can be changed, which can favorably improve the responsiveness of the size change.

The configuration shown in the third means can be suitably realized by arranging multiple light emitters in the scanning direction of the laser light.

Twelfth Means: The size of the laser light includes a first size and a second size larger than the first size,
The change unit is configured so that when the size of the laser light is set to the first size, a specific light-emitting element (laser diode 22a) among the multiple light-emitting elements is the light-emitting target, and when the size of the laser light is set to the second size, the change unit is configured so that the specific light-emitting element among the light-emitting elements and other light-emitting elements (laser diodes 22b, 22c) adjacent to the specific light-emitting element are the light-emitting targets.

If the size of the laser light is changed by turning on/off other light emitters adjacent to a specific light emitter, it is possible to prevent the direction of the laser light from changing due to the size change. This is a preferable configuration for achieving high accuracy in object detection with a simple configuration. For example, it is preferable to configure the optical axis of the laser light to coincide with that of the first size and the second size.

The irradiation unit has a light emitter (laser diode 22X) and a lens unit (variable focus lens 60X) through which light from the light emitter passes,
The change section is configured to change the size of the laser light by changing the focus of the lens by switching a voltage applied to the lens section.

As shown in Means 13, if the laser light passes through a variable focus lens, it is easy to realize a configuration that allows the size of the laser light to be changed arbitrarily.

A fourteenth means includes a case body (case 13) that houses the irradiation unit and the light receiving unit,
The irradiation unit has a light emitter (laser diode 22X) that outputs laser light, and a reflector (second mirror 43) that is rotatably disposed in the scanning direction of the laser light and reflects the laser light from the light emitter, and the laser light reflected by the reflector is irradiated onto the detection area through a transmission portion (window panel 15) of the case body.
The lens portion is disposed such that the optical axis of the lens portion faces the vertical direction and is located between the light emitter and the reflector.

By arranging the lens section so that its optical axis faces vertically, it is possible to prevent distortion of the shape of the lens section or changes in the orientation of the lens section due to the weight of the lens section or the like. This is preferable in terms of preventing deviation of the optical path and ensuring stable detection function. Furthermore, in a configuration in which a rotating reflector is used to change the direction of irradiation of the laser light, the size of the laser light can be easily changed by configuring the output laser light to pass through the lens section before it reaches the reflector, i.e., before the direction of the laser light changes.

1 is a schematic diagram showing a mechanical configuration of a laser radar device according to a first embodiment; 5 is a flowchart showing an area monitoring process executed by a control unit. 1 is a schematic diagram showing the relationship between the spread of laser light and the distance from a laser radar device to a snow particle. 6 is a timing chart showing a flow of false alarms caused by the influence of snow in a conventional laser radar device. FIG. 2A is a schematic diagram showing an irradiation pattern A; FIG. 2B is a schematic diagram showing an irradiation pattern B; 5 is a schematic diagram showing the relationship between irradiation pattern A and irradiation pattern B. Schematic diagram showing a switching manner of irradiation patterns. 11 is a timing chart showing a procedure for avoiding false alarms. 4 is a timing chart showing a flow of vehicle detection. FIG. 11 is a schematic diagram showing a mechanical configuration of a laser radar device according to a second embodiment. FIG. 1 is a schematic diagram showing a variable focus lens. 13A to 13C are schematic diagrams comparing irradiation patterns in the third embodiment. 13 is a flowchart showing an area monitoring process according to the fourth embodiment. FIG. 13 is a schematic diagram showing a monitoring area in a fifth embodiment.

First Embodiment
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment will now be described with reference to the drawings. This embodiment is embodied as a laser radar device that detects an object within a monitoring area.

As shown in FIG. 1, the laser radar device 10 includes an optical mechanism 11 consisting of a light emitter 21, a light receiver 31, and an optical path forming unit 41, a control unit 12 for the optical mechanism 11, and a housing 13 that contains the optical mechanism 11 and the control unit 12.

The light emitting unit 21 includes a PLD array 22 that intermittently outputs pulsed laser light (hereinafter referred to as laser light) in response to the control of the control unit 12, and a collimating lens 23 arranged on the optical path of the laser light output from the PLD array 22, and the laser light is converted into parallel light when passing through the collimating lens 23. Specifically, the PLD array 22 and the collimating lens 23 are both attached to the back wall of the housing 13 so that their optical axes are horizontal, and the laser light converted into parallel light is emitted from the window panel 15 (laser light transmission part) of the housing 13 through the optical path forming part 41 arranged in the center of the housing 13. The laser light may be, for example, infrared light, visible light, ultraviolet light, etc.

The optical path forming unit 41 has a first mirror 42 fixed to the housing 13, a second mirror 43 facing the first mirror 42, and a rotation mechanism 45 that rotates the second mirror 43. The first mirror 42 is formed with a reflecting surface 42a that is inclined obliquely (facing diagonally downward) with respect to the optical axis of the light emitting unit 21, and the laser light output from the light emitting unit 21 is guided by the reflecting surface 42a to the reflecting surface 43a of the second mirror 43.

The reflecting surface 43a of the second mirror 43 is inclined (facing diagonally upward) with respect to the direction in which the mirrors 42, 43 are arranged side by side (the up-down direction), and the laser light reflected by the first mirror 42 is reflected again by the second mirror 43 so as to head toward the window panel 15.

The rotation mechanism 45 has a holder 46 to which the second mirror 43 is attached, a base 47 that is fixed to the housing 13 and rotatably supports the holder 46, and a motor 48 that is a drive unit for rotating the holder 46. The direction of the central axis CL1 that is the center of rotation of the holder 46 (second mirror 43) coincides with the direction of the laser light incident on the second mirror 43 from the first mirror 42, and the incident position P1 of the laser light is specified to be a position on the central axis CL1 on the reflecting surface 43a.

The motor 48 is connected to the control unit 12, and when the motor 48 operates, the holder 46 (second mirror 43) rotates (orbits) around the central axis CL1. This realizes a configuration in which the laser light is sequentially irradiated at irradiation angles set at predetermined angles (e.g., 0.25°). In this embodiment, the scanning direction of the laser light by the laser radar device 10 is horizontal.

When a laser beam is irradiated from the laser radar device 10 to a monitoring area in a situation where an object T is located in the monitoring area, a portion of the laser beam reflected by the object T (hereinafter referred to as reflected beam) reaches the laser radar device 10. In FIG. 1, the laser beam reaching the object T from the laser radar device 10 is labeled L1, and the portion of the reflected beam reflected by the object T that reaches the light receiving unit 31 is labeled L2.

The light receiving unit 31 is disposed above the light path forming unit 41 (the ceiling of the housing 13), and the reflected light is guided to the light receiving unit 31 by the second mirror 43. Specifically, the light receiving unit 31 includes a photodiode 32 attached to the ceiling, a condenser lens 33 (light collecting unit) disposed between the photodiode 32 and the second mirror 43, specifically above the first mirror 42, and a filter 34 disposed between the condenser lens 33 and the photodiode 32, and the reflected light from the second mirror 43 is guided to the photodiode 32 through the condenser lens 33 → filter 34. The filter 34 is a wavelength selection filter that transmits only light of a specific wavelength corresponding to the reflected light and blocks other light, and transmits the reflected light on the optical path from the light path forming unit 41 to the photodiode 32 and removes light other than the reflected light.

In this embodiment, the light-emitting unit 21 and the optical path forming unit 41 (first mirror 42, second mirror 43, and rotation mechanism 45) form an "irradiation unit."

Next, a supplementary explanation will be given of the electrical configuration of the laser radar device 10. The PLD array 22 of the light emitting unit 21 and the photodiode 32 of the light receiving unit 31 are each connected to the control unit 12 of the laser radar device 10, and the motor 48 of the rotation mechanism 45 is also connected via a drive circuit (not shown). The control unit 12 is provided with a calculation unit and a memory unit, and the memory unit stores a control program for the laser radar device and various acquired measurement results (estimated results), while the calculation unit determines the presence or absence of an object based on the measurement results stored in the memory unit. In addition, an alarm unit consisting of a speaker, lamp, etc. is connected to the control unit 12, and when an object is detected in the monitoring area, for example, the alarm unit issues an alarm to that effect.

The processing executed by the calculation unit of the control unit 12 can be broadly divided into main processing, in which laser light is output from the light-emitting unit 21 at each irradiation angle (ANG1 to ANG600) set for each predetermined angle (0.25°), the light-receiving status of the light-receiving unit 31 is confirmed for each irradiation angle, and information relating to the light-receiving status is stored, and area monitoring processing, which determines whether or not an object is located within the monitoring area based on the information stored in the main processing. The main processing is processing executed during scanning, and the area monitoring processing is processing executed repeatedly for each scanning cycle. Here, a supplementary explanation of the area monitoring processing is provided with reference to the flowchart in Figure 2.

In the area monitoring process, first, it is determined whether the amount of light received by the light receiving unit 31 exceeds a preset threshold value D (step S101). Specifically, in the main process, the amount of light received is stored for each irradiation angle, and the amount of light received stored in the previous main process is read out to determine whether the amount of light received exceeds the threshold value D.

If the amount of received light exceeds the threshold D, the distance to the provisional target that is presumed to have reflected the laser light is calculated based on the time from when the laser light is emitted to when the reflected light is received, and it is determined whether the calculated distance is within a reference range L (step S102). This reference range L is determined for each irradiation angle according to the monitoring area. If the calculated distance is within the reference range L, proceed to step S103.

The memory unit of the control unit 12 is provided with a counter for object judgment (hereinafter referred to as the judgment counter) for each irradiation angle. In step S103, an update process is performed to update the value of the judgment counter corresponding to the current irradiation angle. Specifically, the value of the judgment counter is incremented by "1". Then, in step S104, it is determined whether the value of the judgment counter has reached a reference value M ("5" in this embodiment). If a negative determination is made in step S104, the monitoring process is terminated. On the other hand, if a positive determination is made in step S104, an alarm start process is executed to start an abnormality alarm (e.g., an alert) in the alarm unit.

If a negative judgment is made in either step S101 or step S102, the process proceeds to step S106, where the value of the judgment counter is reset (cleared to 0).

In this way, the laser radar device 10 shown in this embodiment does not immediately determine that an object (an object previously assumed to be a detection target) is present in the monitoring area even if a single distance measurement occurs, but determines that an object is located (entering) the monitoring area DE when five consecutive distance measurements occur. In other words, the provisional target is detected as an object previously assumed to be a detection target (corresponding to a "target object"). This improves the accuracy of the detection result. Note that in this embodiment, the function of the control unit 12 that executes the processes of steps S101 to S104 and S106 corresponds to the "determination unit."

When the laser radar device 10 shown in this embodiment is installed at a railroad crossing or platform for the purpose of monitoring people or vehicles entering the tracks, the "target objects" are people and vehicles. The monitoring area can be set outdoors.

The environment of an outdoor monitoring area changes significantly due to weather conditions, etc., and in some cases, snow may fall in the monitoring area. For example, as shown in FIG. 3, when a laser beam hits a snowflake (e.g., peony snowflake) S falling (passing) through the monitoring area DE directly, the amount of reflected laser beam increases, and the amount of light received by the light receiving unit 31 may exceed the threshold value D. In particular, the size (cross-sectional area) of the laser beam is generally kept small from the viewpoint of improving sensitivity, etc. By reducing the difference between the size of the laser beam and the size of the snowflake, the proportion of the laser beam that passes by the side of the snowflake S when it hits directly decreases, making the above-mentioned phenomenon more likely to occur. Note that the laser beam is configured to slightly expand in a direction intersecting the irradiation direction (axis) as it moves away from the light source, and snowflakes passing a position close to the laser radar device 10 are more likely to cause the above-mentioned phenomenon to occur than snowflakes passing a position far from the laser radar device 10.

The timing chart in Figure 4 illustrates the flow of events that occur when a false detection occurs in a conventional laser radar device due to a snow particle S that is not the detection target (corresponding to a "non-target object").

In the example shown in FIG. 4, a snowflake S passes vertically through the monitoring area DE. The time required for the snowflake S to pass through (required time) is about the time required for eight scan cycles to be performed, and the value of the judgment counter is incremented by "1" for each scan cycle. The value of the judgment counter reaches the reference value M when the fifth scan cycle is performed after the snowflake S reaches the upper limit of the monitoring area DE. As a result, the snowflake passing through the monitoring area DE is erroneously detected as a target object, and an alarm or the like is output. There is concern that the frequent occurrence of such an event (false detection determination → alarm) will be a factor that greatly reduces the reliability of the laser radar device 10. One of the features of this embodiment is that it has been devised to take such circumstances into consideration. The devise will be described below with reference to FIG. 5 to FIG. 7.

As shown in the group of Figures 5(1), the light-emitting unit 21 shown in this embodiment has the PLD array 22 in which multiple (three) laser diodes 22a to 22c are arranged in the scanning direction. Each laser diode 22a to 22c can be individually controlled to be turned on (lighted) or off (exited) by the control unit 12. The laser diodes 22a to 22c have common specifications such as brightness and laser light size, but there are slight differences in the lighting conditions. In the following explanation, the central laser diode 22a in the scanning direction is referred to as the first laser diode 22a, and the laser diodes 22b and 22c on either side of the first laser diode 22a are referred to as the second laser diode 22b and the third laser diode 22c.

In this embodiment, the size of the laser light (cross-sectional area: area of the cross section perpendicular to the optical axis) irradiated from the laser radar device 10 to the monitoring area DE can be switched between irradiation pattern A and irradiation pattern B.

Irradiation pattern A is an irradiation pattern in which the size of the laser light is relatively small, and light emission control is performed so that the first laser diode 22a is ON, the second laser diode 22b is OFF, and the third laser diode 22c is OFF. In detail, the size of the laser light in irradiation pattern A is 5 cm in both length and width at a point 5 m from the laser radar device 10 (within the monitoring area DE).

Irradiation pattern B is an irradiation pattern in which the size of the laser light is relatively large, and light emission control is performed so that the first laser diode 22a is ON, the second laser diode 22b is ON, and the third laser diode 22c is ON. The optical path of the laser light from the first laser diode 22a is in contact with the optical paths of the laser light from the second laser diode 22b and the third laser diode 22c, and the size of the laser light output from the laser radar device 10 is larger than irradiation pattern A by the amount of the second laser diode 22b and the third laser diode 22c.

In other words, while the size of the laser light in the direction intersecting (orthogonal to) the scanning direction is the same for irradiation pattern A and irradiation pattern B, the size of the laser light in the scanning direction is different (see group (2) in Figure 5).

As shown in FIG. 6, irradiation pattern A and irradiation pattern B also differ in the luminance of the laser light. Specifically, the luminance is relatively high in irradiation pattern A and relatively low in irradiation pattern B. More specifically, the luminance in irradiation pattern B is suppressed so that the amount of laser light is the same in both irradiation patterns A and B.

Here, a small-sized laser light (laser light of irradiation pattern A) is advantageous in terms of increasing the sensitivity of object detection compared to a large-sized laser light. However, for small-sized laser light, the amount of reflection of the laser light (the ratio of the amount of reflection to the amount of light of the irradiated laser light) is large not only when it is irradiated on large objects (target objects) such as people and cars, but also when it is irradiated on tiny objects (non-target objects) such as snow, especially when it is irradiated on tiny objects passing near the laser radar device 10. For these reasons, when a small-sized laser light is irradiated, there is a higher possibility of detecting tiny objects that would not normally be detected compared to when a large-sized laser light is irradiated. The probability of such an event occurring increases with the amount of snowfall.

Large-sized laser light (laser light of irradiation pattern B) has a lower sensitivity in detecting objects than small-sized laser light. However, when a laser light is irradiated onto a large object (target object) such as a person or a car, the amount of reflection of the laser light (the ratio of the amount of reflection to the amount of light of the irradiated laser light) is sufficient, as with small-sized laser light, whereas when a small object (non-target object) such as snow is irradiated, some of the laser light passes by the side of the small object, resulting in a smaller amount of reflection of the laser light (the ratio of the amount of reflection to the amount of light of the irradiated laser light). In other words, irradiating a large-sized laser light is more advantageous in suppressing the above-mentioned false detections than irradiating a small-sized laser light.

In this embodiment, in order to use these two sizes of laser light with different characteristics in combination, the irradiation pattern A and the irradiation pattern B are switched in a predetermined order according to the number of times the scanning cycle is executed (number of revolutions). Specifically, as shown in FIG. 7, it is specified that the irradiation pattern A is selected when the scanning cycle (number of revolutions) is n, the irradiation pattern A is selected when the scanning cycle (number of revolutions) is n+1, the irradiation pattern A is selected when the scanning cycle (number of revolutions) is n+2, the irradiation pattern A is selected when the scanning cycle (number of revolutions) is n+3, and the irradiation pattern B is selected when the scanning cycle (number of revolutions) is n+4. Then, the above-mentioned switching pattern is repeated from the scanning cycle (number of revolutions) = n+5 onwards. In other words, the irradiation pattern B is selected at least once out of five consecutive scanning cycles (the same number as the above reference value). In other words, the scanning cycle corresponding to the irradiation pattern B is always generated once before the value of the judgment counter reaches the reference value M.

Now, referring to the timing chart in Figure 8, we will explain the flow when switching the irradiation pattern to avoid false detection of tiny objects such as snow. In the example shown in Figure 8, a snowflake S passes vertically through the monitoring area DE, and the time required for the passage (required time) is about the time required for the scanning cycle to be executed eight times.

In the scanning cycle executed when snowflake S enters the monitoring area DE (hereinafter, this scanning cycle will be described as the first scanning cycle), the laser light irradiation pattern is irradiation pattern A. Although the laser light hits the snowflake S, most of the snowflake S is outside the monitoring area DE (outside the irradiation range), and the amount of received light is below the threshold value D. Therefore, the value of the judgment counter is maintained at "0".

In the second scanning cycle, the laser light irradiation pattern is also irradiation pattern A. At this timing, the entire snowflake S is within the monitoring area DE, and the laser light hits the snowflake S directly, causing the amount of light received to exceed the threshold D. As a result, the value of the judgment counter is incremented from "0" to "1." In the third scanning cycle, the laser light irradiation pattern is also irradiation pattern A, and the laser light hits the snowflake S directly again, causing the amount of light received to exceed the threshold D. As a result, the value of the judgment counter is incremented from "1" to "2."

In the third scanning cycle, irradiation pattern A appears four times in a row, and in the fourth scanning cycle, the laser light irradiation pattern switches to irradiation pattern B. Although the laser light irradiated in the fourth scanning cycle also hits the snowflake S directly, the amount of light received is below threshold value D. As a result, the value of the judgment counter is reset from "2" to "0."

In the fifth scanning cycle, the laser light irradiation pattern switches to irradiation pattern A, and the laser light again hits the snowflake S directly, causing the amount of received light to exceed threshold value D. As a result, the value of the judgment counter is incremented from "0" to "1." In the subsequent sixth and seventh scanning cycles, the laser light irradiation pattern remains irradiation pattern A, and in both cases the amount of received light exceeds threshold value D. As a result, the value of the judgment counter is incremented in the order of "1" → "2" → "3."

In the eighth scanning cycle, the laser light irradiation pattern is irradiation pattern A, but approximately one-third of the snowflakes S are outside the monitoring area DE. Therefore, although the laser light hits the snowflakes S, the amount of received light is reduced and falls below the threshold value D. As a result, the value of the judgment counter is reset from "3" to "0."

When the ninth scanning cycle is executed, the irradiation pattern of the laser light becomes irradiation pattern B. The laser light expands in the same direction as the scanning direction (horizontal direction), and does not expand in a direction intersecting the scanning direction (vertical direction). As a result, the laser light does not hit snow grains S that have passed through the monitoring area DE, and the amount of received light remains below threshold value D. In other words, the value of the judgment counter remains at "0".

In this way, when a snowflake S passes through the monitoring area DE, the value of the judgment counter is continuously incremented over multiple scanning cycles, but before the value of the judgment counter reaches the reference value M, the irradiation pattern B intervenes, prompting the judgment counter to be reset. With this configuration, it is possible to suppress the above-mentioned erroneous detection of snowflakes S.

Here, the height of the monitoring area DE is set according to the height of the target object (specifically, a person's torso or a car's body). In other words, the laser radar device 10 is installed on the assumption that if a person enters the monitoring area DE, the laser light will hit the person's torso, and if a car enters the monitoring area DE, the laser light will hit the car's body. The size (cross-sectional area) of the laser light is set to be smaller than the area of the part of the target object that is assumed to be irradiated with the laser light, regardless of whether irradiation pattern A or irradiation pattern B is used. This prevents the target object that should be detected from being overlooked due to the intervention of irradiation pattern B. Below, the flow of detection when a target object, a car V, enters the monitoring area DE will be described with reference to the timing chart in Figure 9.

In the example shown in FIG. 9, a vehicle V enters the monitoring area DE. In the scanning cycle executed at the time when the vehicle V enters the monitoring area DE (hereinafter, this scanning cycle will be described as the first scanning cycle), the irradiation pattern of the laser light is irradiation pattern A. The amount of light received exceeds threshold value D as the laser light hits the vehicle V directly. As a result, the value of the judgment counter is incremented from "0" to "1."

In the second scanning cycle that follows, the laser light irradiation pattern is also irradiation pattern A, and the laser light again hits vehicle V directly, causing the amount of light received to exceed threshold value D. As a result, the value of the judgment counter is incremented from "1" to "2."

In the second scanning cycle, irradiation pattern A is repeated four times in a row, and in the third scanning cycle, the laser light irradiation pattern becomes irradiation pattern B. The laser light irradiated in the third scanning cycle also hits vehicle V directly, and although the amount of light received is slightly lower than in the case of irradiation pattern A, it still exceeds threshold value D. As a result, the value of the judgment counter is incremented from "2" to "3."

In the fourth scanning cycle, the laser light irradiation pattern becomes irradiation pattern A again, and the laser light again hits the vehicle V directly, causing the amount of received light to exceed threshold value D. As a result, the value of the judgment counter is incremented from "3" to "4."

In the fifth scanning cycle, the irradiation pattern of the laser light is still irradiation pattern A, and the amount of received light again exceeds threshold value D as the laser light hits vehicle V directly. As a result, the value of the judgment counter is incremented from "4" to "5." The value of the judgment counter reaches reference value M when the fifth scanning cycle is executed after vehicle V enters monitoring area DE. As a result, the intrusion of a target object into monitoring area DE is detected, and an alarm or the like is output.

The first embodiment described above provides the following excellent effects:

When a laser beam is irradiated onto an object (target object) such as a person or a car that has entered the monitoring area DE, the amount of light received at the same irradiation angle continuously exceeds the threshold D, and the number of consecutive occurrences reaches a reference value M, it is determined that the object is located in the monitoring area DE. In contrast, when a laser beam is irradiated onto a tiny object (non-target object) such as snow passing through the monitoring area DE, and the amount of light received at the same irradiation angle for the tiny object continuously exceeds the threshold D, the irradiation pattern of the laser beam becomes irradiation pattern B before the number of consecutive occurrences reaches the reference value M. This causes the continuity to be broken. In other words, for tiny objects, the number of consecutive occurrences of the amount of light received exceeding the threshold D can be set to be less than the reference value M. By intentionally excluding tiny objects from detection in this way, false detections caused by the tiny objects can be suitably suppressed.

As described above, the sensitivity of object detection is irradiation pattern B < irradiation pattern A. Therefore, by making the number of times that the laser light is emitted with irradiation pattern A greater than the number of times that the laser light is emitted with irradiation pattern B, it is possible to effectively suppress a decrease in the sensitivity of object detection.

By changing the number of laser diodes to be turned on among the multiple laser diodes 22a to 22c, the size of the laser light can be changed, and the responsiveness of the size change can be suitably improved.

In particular, if the size of the laser light is changed by turning on/off the other laser diodes 22b and 22c adjacent to the first central laser diode 22a, it is possible to prevent the direction of the laser light from changing due to the size change. This is a preferable configuration for achieving high accuracy in object detection with a simple configuration.

As shown in this embodiment, if the size of the laser light is changed in the scanning direction, the irradiation area when a large-sized laser light is irradiated onto an object (target object) such as a person or car within the area, i.e., the amount of reflection from the target object, can be suitably increased. This is preferable in terms of preventing the target object from being overlooked.

For example, even if multiple laser beams of different sizes are used in combination at all times, it is possible to suppress false detections in the same way as the laser radar device 10 shown in this embodiment. However, such a laser radar device consumes a large amount of power. In this regard, if the size of the irradiated laser beam is changed as shown in this embodiment, power consumption can be reduced compared to the above-mentioned type of laser radar device that is used in combination at all times.

Second Embodiment
In the first embodiment, the size of the laser light irradiated from the laser radar device 10 to the monitoring area DE is switched by changing the number of laser diodes that are turned on. In this embodiment, the configuration related to switching the size of the laser light is different from that of the first embodiment. Hereinafter, the configuration related to size switching in this embodiment will be described with reference to Figures 10 and 11, focusing on the differences from the first embodiment.

As shown in FIG. 10, in the laser radar device 10X shown in this embodiment, the positional relationship between the light emitting unit and the light receiving unit is reversed from that of the laser radar device 10 shown in the first embodiment. That is, the light emitting unit 21X is disposed above the light path forming unit 41X, and the light receiving unit 31 is disposed behind the light path forming unit 41X.

The laser diode 22X constituting the light-emitting unit 21X is arranged so that its optical axis coincides with the central axis of rotation (central axis CL1) of the second mirror 43, and the laser light output from the laser diode 22X reaches the second mirror 43 through a through hole 42bX formed in the center of the first mirror 42X.

A variable focus lens 60X (more specifically, a liquid lens) is disposed between the laser diode 22X and the collimating lens 23. The central axis (optical axis) of the variable focus lens 60X also coincides with the central axis CL1, similar to the laser diode 22X and the collimating lens 23, and the laser light output from the laser diode 22X passes through the variable focus lens 60X before being converted into parallel light by the collimating lens 23. It is also possible for the variable focus lens 60X to be an electro-optical element lens.

The variable focus lens 60X is connected to the control unit 12, and the lens curvature (position of the focal point) changes in response to an electrical signal (applied voltage) from the control unit 12. The change in lens curvature changes the size of the laser light passing through the variable focus lens 60X. Specifically, when the voltage applied to the variable focus lens 60X is at a LOW level, the lens curvature becomes curvature A, resulting in irradiation pattern A in which the size of the laser light is relatively small. In contrast, when the voltage applied to the variable focus lens 60X is at a HI level, the lens curvature becomes curvature B, resulting in irradiation pattern B in which the size of the laser light is relatively large (see FIG. 11).

In this embodiment, the lens curvature (position of the focal point) is changed while the second mirror 43 faces away from the monitoring area DE during the scanning cycle, thereby preventing the need to ensure time for the curvature change from being a factor that impedes a rapid transition to the next scanning cycle.

Third Embodiment
In the first embodiment, the size of the laser light irradiated from the laser radar device 10 to the monitoring area DE is enlarged/reduced only in the scanning direction. In the present embodiment, in addition to the size in the scanning direction, the size is also enlarged/reduced in the direction intersecting (perpendicular to) the scanning direction. Specifically, as shown in FIG. 12(a)→FIG. 12(b), the size is enlarged in all directions intersecting the optical axis (center axis) of the laser light by changing from the irradiation pattern A to the irradiation pattern B. Even when the size of the laser light is increased overall in this way, it is preferable to make the optical axis of the laser light consistent before and after the change.

For example, the PLD array can be configured with a total of nine laser diodes (3 x 3), and in irradiation pattern A the central laser diode can be turned ON and the other laser diodes OFF, while in irradiation pattern B all of the laser diodes can be turned ON.

Fourth Embodiment
In the first embodiment, the irradiation pattern of the laser light is switched in a predetermined order. In this embodiment, the irradiation pattern of the laser light is switched depending on the reception state of the reflected light, specifically, the processing content of the area monitoring processing is different from that of the first embodiment. The area monitoring processing in this embodiment will be described below with reference to Fig. 13. Note that the structure of the laser radar device 10 is similar to that of the first embodiment, and therefore the description will be omitted.

In the area monitoring process, first, it is determined whether the amount of light received by the light receiving unit 31 exceeds a preset threshold D (step S201). If the amount of light received exceeds the threshold D, the distance to the provisional target that is estimated to have reflected the laser light is calculated, and it is determined whether the calculated distance is within the reference range L (step S202). If the calculated distance is within the reference range L, the value of the judgment counter corresponding to the current irradiation angle is incremented by "1" (step S203). Then, it is determined whether the value of the judgment counter has reached a reference value M ("5" in this embodiment) (step S204). If the reference value M has been reached, the above-mentioned notification unit executes a notification start process to start an abnormality notification (e.g., an alert) (step S205). If a negative determination is made in either step S201 or step S202, the value of the judgment counter is reset (cleared to 0) (step S208). In other words, even if one distance measurement occurs, it is not immediately determined that an object (an object previously assumed to be a detection target) is present in the monitoring area, but if five distance measurements occur in succession, it is determined that an object is located (entering) the monitoring area DE. In other words, the provisional target is detected as an object previously assumed to be a detection target (corresponding to a "target object"). The processes in steps S201 to S205 and S208 are the same as those in steps S101 to S105 and S106.

If a negative judgment is made in step S204, the process proceeds to step S206. In step S206, it is judged whether the value of the judgment counter is equal to the second reference value N. The second reference value N is a value smaller than the first reference value M ("3" in this embodiment). If a negative judgment is made in step S206, the area monitoring process is terminated. If a positive judgment is made in step S206, the irradiation pattern B flag is set in the memory unit in step S207, and the area monitoring process is terminated.

The irradiation pattern B flag is a flag referenced in the main processing described above, and when the irradiation pattern B flag is set, the irradiation pattern of the laser light becomes irradiation pattern B. On the other hand, when the irradiation pattern B flag is not set, the irradiation pattern of the laser light becomes irradiation pattern A. The irradiation pattern B flag set in step S207 is erased when the value of the determination counter is reset in step S208.

When a minute object is intentionally excluded from detection by changing the laser light irradiation pattern to irradiation pattern B before the first reference value M is reached, the decrease in sensitivity of object detection can be minimized by quickly returning the irradiation pattern to irradiation pattern A after the exclusion.

Fifth embodiment
In the fourth embodiment, the irradiation pattern is fixed to either the irradiation pattern A or the irradiation pattern B from the start of each scanning cycle to the end of the cycle, that is, the irradiation pattern is the same at any irradiation angle during one scanning cycle. This embodiment differs from the fourth embodiment in that the irradiation pattern A and the irradiation pattern B can be switched depending on the irradiation angle during the scanning cycle. Hereinafter, the configuration related to the determination of the irradiation pattern will be described with reference to the schematic diagram of FIG. 14, focusing on the differences from the fourth embodiment.

In this embodiment, the monitoring area DE is divided into multiple individual areas in the scanning direction, and the laser light irradiation pattern is determined for each individual area. Specifically, there are three individual areas: right area DER (irradiation angle ANG1-ANG200), middle area DEM (irradiation angle ANG201-ANG400), and left area DEL (irradiation angle ANG401-ANG600), and the configuration differs from the fourth embodiment in that the irradiation pattern can be switched for each of the areas DER, DEM, and DEL during the scanning cycle.

For the irradiation pattern in the individual area DER in the next scanning cycle, the values of the judgment counters for the irradiation angles corresponding to the individual area DER are referenced. In other words, if the value of any judgment counter corresponding to the individual area DER reaches the reference value N, the irradiation pattern in the individual area DER in the next scanning cycle will be irradiation pattern B, and if the value of any judgment counter corresponding to the individual area DER does not reach the reference value N, the irradiation pattern in the individual area DER in the next scanning cycle will be irradiation pattern A.

For the irradiation pattern in the individual area DEM in the next scanning cycle, the values of the judgment counters for the irradiation angles corresponding to the individual area DEM are referenced. In other words, if the value of any judgment counter corresponding to the individual area DEM reaches the reference value N, the irradiation pattern in the individual area DEM in the next scanning cycle will be irradiation pattern B, and if the value of any judgment counter corresponding to the individual area DEM does not reach the reference value N, the irradiation pattern in the individual area DEM in the next scanning cycle will be irradiation pattern A.

For the irradiation pattern in the individual area DEL in the next scanning cycle, the values of the judgment counters for the irradiation angles corresponding to the individual area DEL are referenced. In other words, if the value of any judgment counter corresponding to the individual area DEL reaches the reference value N, the irradiation pattern in the individual area DEL in the next scanning cycle will be irradiation pattern B, and if the value of any judgment counter corresponding to the individual area DEL does not reach the reference value N, the irradiation pattern in the individual area DEL in the next scanning cycle will be irradiation pattern A.

In this way, by dividing the monitoring area DE into multiple individual areas and making it possible to switch the irradiation pattern for each individual area, it is possible to maximize the opportunities for irradiation with irradiation pattern A. This is preferable in terms of preventing a decrease in object detection sensitivity due to the suppression of false detections.

<Other embodiments>
In each of the above embodiments, the frequency of the irradiation pattern A is different from the frequency of the irradiation pattern B, but the present invention is not limited to this. It is also possible to make the frequency of the irradiation pattern A the same as the frequency of the irradiation pattern B. For example, the irradiation pattern may be switched so that the irradiation pattern A and the irradiation pattern B alternate.

- In each of the above embodiments, the optical path (irradiation area) of the laser light output in irradiation pattern A is included in the optical path (irradiation area) of the laser light output in irradiation pattern B, but this is not limited to the above. A configuration in which a part of the optical path of the laser light output in irradiation pattern A overlaps with a part of the optical path of the laser light output in irradiation pattern B may be used, or a configuration in which the optical path of the laser light output in irradiation pattern A does not overlap with the optical path of the laser light output in irradiation pattern B may be used.

- In each of the above embodiments, the laser light is switched between two irradiation patterns A and B of different sizes, but the number of irradiation patterns of different sizes may be changed arbitrarily as long as it is two or more. For example, it may be three or four. When such multi-stage switching is assumed, it is preferable to configure the irradiation pattern to be switched so that the size of the laser light is increased in stages as the value of the judgment counter approaches the reference value M, for example.

- In each of the above embodiments, the cross section of the laser light (cross section perpendicular to the optical axis) is rectangular, but the cross section of the laser light may be changed as desired. For example, it may be circular (including elliptical).

- In each of the above embodiments, the luminance of the laser light is reduced when irradiation pattern B is reached, but this is not limited to the above. Instead, it is also possible to configure the threshold D to be increased when irradiation pattern B is reached. For example, if the amount of light (total amount) of the laser light is tripled by changing from irradiation pattern A to irradiation pattern B, the threshold should also be tripled.

- In the first embodiment and the like, when the laser diodes 22a to 22c are turned on, the outer edge of the laser light from the first laser diode 22a comes into contact with the outer edge of the laser light from the second laser diode 22b and the outer edge of the laser light from the third laser diode 22c, but this is not limited to the above. For example, when the laser diodes 22a to 22c are turned on, a blank can be generated between the laser light from the first laser diode 22a, the laser light from the second laser diode 22b, and the laser light from the third laser diode 22c. It is also possible to configure the laser light from the first laser diode 22a, the laser light from the second laser diode 22b, and the laser light from the third laser diode 22c to partially overlap (a configuration in which overlap occurs). However, since the brightness is high in the overlapping portion of the laser light, it is assumed that the amount of reflection will be large when this overlapping portion hits a small object such as snow directly. In consideration of such circumstances, it is preferable to configure the laser light from each laser diode to avoid mutual overlap.

- In the first embodiment and the like, the PLD array 22 is configured with three laser diodes 22a to 22c, but it is sufficient if the number of laser diodes that are turned on in each irradiation pattern can be made different, and the number of laser diodes may be changed as desired. For example, the number of laser diodes may be four or five.

The PLD array 22 shown in the first embodiment and the like is configured with multiple laser diodes arranged in the scanning direction (horizontal direction), but in addition to or instead of this, it is also possible to configure the array with multiple laser diodes arranged in a direction perpendicular to the scanning direction (vertical direction).

- In the second embodiment described above, the variable focus lens 60X is arranged so that the optical axis of the variable focus lens 60X is vertical, but it is also possible to arrange the variable focus lens 60X so that the optical axis of the variable focus lens 60X is horizontal. In addition, the arrangement of the variable focus lens 60X is not limited to between the collimator lens 23 and the second mirror 43. For example, the variable focus lens 60X can be arranged between the laser diode 22X and the collimator lens 23.

The relationship between the applied voltage and the size of the laser light shown in the second embodiment may be reversed. That is, when the voltage applied to the variable focus lens 60X is at a LOW level, the size of the laser light is relatively large, resulting in irradiation pattern B, and when the voltage applied to the variable focus lens 60X is at a HI level, the size of the laser light is relatively small, resulting in irradiation pattern A.

- In each of the above embodiments, the case where the monitoring area DE is set outdoors has been exemplified, but with the laser radar device 10 shown in each of the above embodiments, the following effects can be expected when the monitoring area DE is set indoors (e.g., a factory, etc.). That is, in a factory, minute objects such as dust and debris may fall from the ceiling, etc. into the monitoring area DE that monitors the intrusion of workers, etc. This can reduce false detections when such minute objects pass through the monitoring area DE, contributing to improved reliability of the monitoring function.

10...laser radar device, 11...optical mechanism, 12...control unit, 13...housing, 15...window panel, 21, 21X...light emitter, 22...PLD array, 22X...laser diode, 22a-22c...laser diodes, 31...light receiver, 32...photodiode, 43...second mirror, 60X...variable focus lens, CL1...rotation center axis, DE...surveillance area, DEL, DEM, DER...individual area, S...snowflake, T...object, V...vehicle.

Claims (11)

an irradiation unit that repeats a scanning cycle of sequentially irradiating the laser light to irradiation angles set for each predetermined angle;
a light receiving unit that receives reflected light, which is the laser light reflected by an object;
a determination unit that determines that an object reflecting the laser light is located in a detection area when a state in which the amount of the reflected light received exceeds a predetermined threshold and a distance calculated based on a time from the irradiation of the laser light to the reception of the reflected light is included in a predetermined reference range occurs consecutively at the same irradiation angle and the number of consecutive occurrences reaches a predetermined number ;
a change unit capable of changing a size of an irradiation cross section of the laser light irradiated from the irradiation unit to the detection area for each scanning cycle ,
The size of the laser light includes a first size and a second size larger than the first size,
The laser radar device is configured such that the change unit changes the size of the laser light to the second size at least once out of the predetermined number of consecutive scanning cycles . The laser radar device according to claim 1, further comprising a means for changing at least one of the luminance of the laser light and the judgment condition by the judgment unit when the size of the laser light is changed by the change unit. The laser radar device according to claim 1 or 2, wherein the change unit is configured to change the size of the laser light at least in the scanning direction of the laser light. 4. The laser radar device according to claim 1, wherein the number of times that the size of the laser light becomes the second size in the predetermined number of scanning cycles is less than the number of times that the size of the laser light becomes the first size. an irradiation unit that repeats a scanning cycle of sequentially irradiating the laser light to irradiation angles set for each predetermined angle;
a light receiving unit that receives reflected light, which is the laser light reflected by an object;
a determination unit that determines that an object reflecting the laser light is located in a detection area when a state in which the amount of the reflected light received exceeds a predetermined threshold and a distance calculated based on a time from the irradiation of the laser light to the reception of the reflected light is included in a predetermined reference range occurs consecutively at the same irradiation angle and the number of consecutive occurrences reaches a predetermined number;
a change unit capable of changing the size of an irradiation cross section of the laser light irradiated from the irradiation unit to the detection area for each scanning cycle;
Equipped with
The size of the laser light includes a first size and a second size larger than the first size ,
The laser radar device is configured such that the change unit changes the size of the laser light to the second size when the state occurs consecutively at the same irradiation angle and the number of consecutive occurrences reaches a specific number that is less than the predetermined number. 6. The laser radar device according to claim 5, wherein if the state does not occur at the same irradiation angle in a scanning cycle in which the size of the laser light is changed to the second size by the change unit, the size of the laser light in a next scanning cycle is changed to the first size. The detection area is divided into a plurality of individual areas in a scanning direction of the laser light,
7. The laser radar device according to claim 1 , wherein the change unit is capable of changing a size of the laser light for each of the individual areas. The irradiation unit has a plurality of light emitters,
8. The laser radar device according to claim 1 , wherein the change unit is configured to change the size of the laser light by changing the number of light-emitting elements that are to be light-emitting objects among the plurality of light-emitting elements. The laser radar device of claim 8, wherein the change unit is configured to target a specific light-emitting element among the multiple light-emitting elements as the light emission target when the size of the laser light is set to the first size, and to target the specific light-emitting element among the light-emitting elements and other light-emitting elements adjacent to the specific light-emitting element as the light emission target when the size of the laser light is set to the second size. The irradiation unit has a light emitting body and a lens unit through which light from the light emitting body passes,
8. The laser radar device according to claim 1 , wherein the change unit is configured to change the size of the laser light by switching a voltage applied to the lens unit to change the focus of the lens. a case body that houses the irradiation unit and the light receiving unit,
the irradiation unit has a light-emitting body that outputs laser light, and a reflection unit that is rotatably disposed in a scanning direction of the laser light and reflects the laser light from the light-emitting body, and the laser light reflected by the reflection unit is irradiated onto the detection area through a transmission unit of the case body;
The laser radar device according to claim 10 , wherein the lens portion is disposed such that an optical axis of the lens portion is oriented in a vertical direction and is located between the light emitter and the reflector.

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