JP2010097354A - Surroundings monitoring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surroundings monitoring apparatus capable of measuring a position of another vehicle with high accuracy by an easy method. <P>SOLUTION: The surroundings monitoring apparatus includes a detection means and a measurement means. The detection means sets a prescribed area on a road surface in one's own vehicle travel direction as a detection area, and detects a light projection pattern formed in the detection area by associating positional relationship between a projection position formed with the light projection pattern and the position of the other vehicle to size of the light projection pattern, by the other vehicle. The measurement means measures the positional relationship between the projection position and the other vehicle based on the size of the light projection pattern detected by the detection means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle periphery monitoring device, and more specifically to a periphery monitoring device that measures the position of another vehicle by detecting a light projection pattern formed on the road surface by the other vehicle.

Conventionally, there is a periphery monitoring device that determines the possibility of collision between the host vehicle and the other vehicle by detecting a light projection pattern formed on the road surface by the other vehicle irradiating the light beam. For example, in the apparatus described in Patent Document 1, the own vehicle and other vehicles irradiate a light beam to form a predetermined light projection pattern on a road surface, and the light projection pattern formed by the own vehicle and the other vehicle is captured by a camera. By detecting this, the possibility of collision between the host vehicle and another vehicle is determined. Specifically, the vehicle (the host vehicle and the other vehicle) calculates a travel path estimated to travel the vehicle based on the vehicle speed, the motion state amount, the steering angle, and the steering force of the vehicle. Next, a region through which the vehicle body passes when the vehicle travels on the traveling track is calculated, and a light beam is irradiated on a boundary line between the region and a region through which the vehicle body does not pass. Thereby, the vehicle forms two linear light projection patterns on the road surface. When the light beam formed on the road surface by the own vehicle interferes with the light projection pattern formed on the road surface by another vehicle (the linear light beams intersect), the own vehicle and the other vehicle collide. It is determined that there is a possibility, and processing such as alerting the driver is performed.
JP 2003-231450 A

  However, in the above apparatus, in order to determine whether or not the light projection patterns of the host vehicle and the other vehicle intersect, it is necessary to perform complicated processing such as processing for analyzing an image captured by the camera. When such a complicated process is performed, the process may take a long time and collision determination may be delayed, or hardware having a high processing capability for performing the complicated process may be required, resulting in high costs. In order to accurately determine the possibility of collision between the host vehicle and the other vehicle, it is preferable to measure the positional relationship between the host vehicle and the other vehicle with high accuracy.

  Therefore, an object of the present invention is to provide a periphery monitoring device that can accurately measure the position of another vehicle by a simple method.

  The present invention employs the following configuration in order to solve the above problems. That is, the first invention is a periphery monitoring device that measures the position of another vehicle by detecting a light projection pattern formed on the road surface when the other vehicle emits light. The perimeter monitoring device includes detection means and measurement means. The detection means uses a predetermined area on the road surface in the traveling direction of the host vehicle as a detection area, and the positional relationship between the projection position where the other vehicle forms the light projection pattern and the position of the other vehicle in the detection area. The measuring means for detecting the light projection pattern formed in correspondence with the size of the object measures the positional relationship between the projection position and the other vehicle based on the size of the light projection pattern detected by the detection means.

  According to this invention, when the own vehicle detects the light projection pattern formed on the road surface by the other vehicle, the positional relationship between the other vehicle and the projection position of the light projection pattern formed by the other vehicle can be obtained. . That is, the other vehicle forms the light projection pattern on the road surface with the positional relationship corresponding to the size of the light projection pattern. The host vehicle obtains the size of the light projection pattern formed by the other vehicle. Thereby, the own vehicle can obtain | require the positional relationship of the said projection position and another vehicle.

  In the present invention, the other vehicle associates the distance from the other vehicle to the projection position with the size of the light projection pattern as the positional relationship between the projection position and the other vehicle, and the distance from the other vehicle to the projection position and the light projection pattern. You may irradiate a light beam so that ratio with the magnitude | size of may become constant. In this case, the measuring unit measures the size of the light projection pattern and calculates the distance from the other vehicle to the projection position based on the measurement result.

  According to this configuration, the distance from the other vehicle to the projection position of the light projection pattern can be accurately obtained. That is, the other vehicle irradiates the light beam so that the ratio of the distance from the other vehicle to the projection position and the size of the light projection pattern is constant. As a result, even when the other vehicle tilts in the vertical direction due to the pitch motion and the projection position of the light projection pattern changes, the size of the light projection pattern also changes according to the change in the distance from the other vehicle to the projection position. The host vehicle can accurately determine the distance from the other vehicle to the projection position by determining the size of the light projection pattern.

  In the present invention, the other vehicle associates the arrival time until the other vehicle reaches the projection position as the positional relationship between the projection position and the other vehicle according to the size of the light projection pattern. You may irradiate a light beam so that ratio with a magnitude | size may become fixed. In this case, the measurement unit may measure the size of the light projection pattern and calculate the arrival time based on the measurement result.

  According to this configuration, it is possible to accurately obtain the time until the other vehicle reaches the projection position of the light projection pattern. That is, the other vehicle irradiates the light beam so that the ratio of the time until the other vehicle reaches the projection position and the size of the light projection pattern is constant. As a result, even when the other vehicle tilts in the vertical direction due to pitch movement and the projection position of the light projection pattern changes, the size of the light projection pattern also changes according to the change in time until the other vehicle reaches the projection position. Therefore, the host vehicle can accurately determine the time until the other vehicle reaches the projection position by determining the size of the light projection pattern.

  In the present invention, the light projection pattern may be a plurality of light spots formed on the road surface by irradiating a plurality of light pulses at predetermined time intervals.

  According to this configuration, when the other vehicle forms a light spot on the road surface, the own vehicle can obtain the positional relationship between the other vehicle and the projection position of the light spot.

  In the present invention, the measurement unit may calculate the size of the light projection pattern based on the detection time intervals of the plurality of light spots detected by the detection unit.

  According to this configuration, the host vehicle can calculate the size of the light projection pattern based on the time intervals between the plurality of light spots detected by the detection unit. Thereby, the own vehicle can obtain | require the positional relationship of the said projection position and another vehicle.

  In the present invention, the other vehicle forms a light spot of the first pattern row and the second pattern row arranged in a line on the road surface by irradiating a plurality of light pulses at predetermined time intervals as the light spot. May be. In this case, the measurement unit is based on the difference between the detection time intervals of the plurality of light spots included in the first pattern row detected by the detection unit and the detection time intervals of the plurality of light spots included in the second pattern. Then, the size of the light projection pattern is calculated. Further, the second pattern row is formed at a position different from the first pattern row in a direction different from the first pattern row at a position different from the first pattern row at a position different from the first pattern row.

  According to this configuration, the vehicle can determine the size of the light projection pattern by determining the difference between the detection time interval of the first pattern sequence and the detection time interval of the second pattern sequence.

  In the present invention, the first pattern row is formed on a circumference of a part of a predetermined ellipse, and the second pattern row is formed at a position different from the first pattern row on the circumference of the ellipse. Also good.

  According to this configuration, the host vehicle can determine the size of the light projection pattern regardless of the angle of the traveling direction of the other vehicle with respect to the traveling direction of the host vehicle. Thereby, the own vehicle can obtain | require the positional relationship of another vehicle and a projection position.

  In the present invention, the measuring means may measure the angle between the host vehicle and the other vehicle based on the detection time interval of the light spot included in the first pattern row and the second pattern row detected by the detecting portion. Good.

  According to this configuration, the angle between the host vehicle and the other vehicle can be obtained by measuring the time interval of the light spots in the first pattern row and measuring the time interval of the light spots in the second pattern row. it can.

  The present invention may further include a collision determination unit that determines a collision between the host vehicle and another vehicle based on measurement information obtained by the measurement unit.

  According to this configuration, a collision between the host vehicle and the other vehicle can be predicted based on the position of the other vehicle measured by the measuring unit.

  The second aspect of the present invention is a periphery monitoring device that measures the position of another vehicle by detecting a light projection pattern formed on the road surface by the other vehicle irradiating light. The perimeter monitoring device includes detection means and measurement means. The detection means uses a predetermined area on the road surface in the traveling direction of the host vehicle as a detection area, and detects a light projection pattern formed in a predetermined area on the road surface by the other vehicle in the detection area. The measuring means measures the angle of the traveling direction of the other vehicle with respect to the traveling direction of the own vehicle, based on the light projection pattern seen from the own vehicle detected by the detecting means.

  According to this invention, when the own vehicle detects the light projection pattern formed on the road surface by the other vehicle, the angle between the own vehicle and the other vehicle can be measured.

  In the present invention, the other vehicle may form a plurality of light spots in a predetermined arrangement on the road surface by irradiating a plurality of light pulses at predetermined time intervals as the light projection pattern. In this case, the measurement unit may measure the angle based on the arrangement of the plurality of light spots detected by the detection unit as viewed from the host vehicle.

  According to this configuration, the host vehicle can determine the angle of the traveling direction of the other vehicle with respect to the traveling direction of the host vehicle by detecting the pattern of the light spot formed by the other vehicle.

  In the present invention, the measuring means may calculate the angle based on detection time intervals of a plurality of light spots detected by the detecting means.

  According to this configuration, the host vehicle can calculate the angle of the traveling direction of the other vehicle with respect to the traveling direction of the host vehicle based on the time intervals between the plurality of light spots detected by the detecting unit.

  In the present invention, the other vehicle forms a light spot of the first pattern row and the second pattern row aligned on the road surface by irradiating a plurality of light pulses at predetermined time intervals as the light projection pattern. May be. In this case, the measuring unit is based on the detection time intervals of the plurality of light spots included in the first pattern sequence detected by the detection unit and the detection time intervals of the plurality of light spots included in the second pattern sequence. The angle is calculated. Further, the second pattern row is formed at a position different from the first pattern row in a direction different from the first pattern row at a position different from the first pattern row at a position different from the first pattern row.

  According to this configuration, the own vehicle measures the detection time interval of the first pattern sequence and the detection time interval of the second pattern sequence, thereby determining the angle of the traveling direction of the other vehicle with respect to the traveling direction of the own vehicle. Can be sought.

  In the present invention, the first pattern row is formed substantially perpendicular to the traveling direction of the other vehicle, and the second pattern row has a first pattern row whose direction is a trajectory connecting a plurality of light spots in the irradiation order. It may be formed in the opposite direction.

  According to this configuration, the own vehicle detects a light spot formed substantially at right angles to the traveling direction of the other vehicle, and based on the detection time interval of each light spot, the positional relationship between the other vehicle and the projection position and The angle between the other vehicle and the host vehicle can be obtained.

  The present invention may further include a collision determination unit that determines a collision between the host vehicle and another vehicle based on measurement information obtained by the measurement unit.

  According to this configuration, a collision between the host vehicle and the other vehicle can be predicted based on the position of the other vehicle measured by the measuring unit.

  In the present invention, the collision determination unit may determine that no collision occurs when the size of the light projection pattern detected by the detection unit is greater than or equal to a predetermined size.

  According to this configuration, when the size of the light projection pattern detected by the detection unit is greater than or equal to the predetermined size, the host vehicle can determine that the distance between the other vehicle and the projection position is greater than or equal to the predetermined distance. it can. Therefore, it can be determined that the host vehicle does not collide.

  The present invention may further include a collision determination unit that determines a collision between the host vehicle and another vehicle based on measurement information obtained by the measurement unit. The collision determination unit may determine that the collision does not occur when the difference between the detection time intervals of the plurality of light spots detected by the detection unit and the predetermined time interval is not within a predetermined range.

  According to this configuration, when the distance between the other vehicle and the projection position is a predetermined distance or more, the deviation in the detection time interval becomes large. In this case, the possibility of collision between the host vehicle and the other vehicle is low. Further, when the host vehicle and the other vehicle are running facing each other or running in parallel, the deviation in the detection time interval is reduced. In this case, there is a high possibility that the own vehicle and the other vehicle pass each other. Therefore, when the shift of the detection time interval is not within the predetermined range, the host vehicle can determine that the host vehicle and the other vehicle do not collide.

  In the present invention, the other vehicle may form a plurality of sets of light projection patterns at positions where the distances from the other vehicle are different from each other, with the light projection pattern formed at the projection position as one set.

  According to this configuration, when the own vehicle detects one set of the plurality of sets of light projection patterns formed by the other vehicle, the own vehicle has a positional relationship between the other vehicle and the projection position of the light projection pattern of the set. Can be requested.

  A third invention is a periphery monitoring device that measures the position of another vehicle by irradiating the other vehicle with light. The perimeter monitoring device includes detection means and measurement means. The detection means uses a predetermined area on the road surface in the traveling direction of the host vehicle as a detection area, and a plurality of light blank projections in which the light formed on the road surface by other vehicles shielding a part of the light is not irradiated to the detection area Detect patterns. The measurement unit measures the positional relationship between the projection position and the other vehicle based on the size of the light blank projection pattern detected by the detection unit. The other vehicle forms the light blank projection pattern by making the positional relationship between the projection position and the position of the other vehicle correspond to the size of the light blank projection pattern.

  According to this structure, the own vehicle can obtain | require the positional relationship of another vehicle and the projection position of a light blank projection pattern with the light blank projection pattern formed on a road surface.

  In the present invention, the light blank projection pattern may be a plurality of light blank spots formed on the road surface by shielding a part of the light.

  According to this configuration, when the other vehicle forms the light blank spot on the road surface as the light blank projection pattern, the host vehicle can determine the positional relationship between the other vehicle and the projection position of the light blank projection pattern. .

  When the other vehicle detects the light projection pattern formed on the road surface by making the positional relationship between the other vehicle and the projection position of the light projection pattern correspond to the size of the light projection pattern, The positional relationship between the vehicle and the projection position can be obtained.

(First embodiment)
Hereinafter, the periphery monitoring device according to the first embodiment will be described with reference to FIGS. 1 to 13. FIG. 1 is a block diagram illustrating a configuration of the periphery monitoring device according to the first embodiment. The periphery monitoring device 1 measures the position of the other vehicle by detecting a light projection pattern formed on the road surface when the other vehicle emits light. As shown in FIG. 1, the periphery monitoring device 1 includes a detection unit 2, a measurement unit 3, an irradiation unit 4, and a collision determination unit 5. Hereinafter, each part will be described.

(Description of each part of the periphery monitoring device 1)
The detection means 2 detects a light projection pattern formed in the detection area when another vehicle having the irradiation means 4 emits light with a predetermined area on the road surface in the traveling direction of the host vehicle as a detection area. In this embodiment, the other vehicle irradiates a plurality of light pulses to form a plurality of light spots on the road surface. The detection unit 2 includes a lens 11, a filter 12, and a light receiving element 13. The lens 11 collects light incident from a detection area in front of the vehicle. The filter 12 transmits light having a predetermined wavelength out of the collected light. Here, the light of a predetermined wavelength is light emitted from the irradiation means 4 by another vehicle, for example, infrared light. The light receiving element 13 receives the light transmitted through the filter 12. The light receiving element 13 does not have spatial resolution and converts received light into an electrical signal. The converted electrical signal is output to the measuring means 3. As described above, the light spot formed in the detection region is detected through the lens 11, the filter 12, and the light receiving element 13. The light receiving element 13 may have a spatial resolution. Moreover, the detection means 2 may be adjusted so that the distance from the own vehicle to the detection area changes according to the vehicle speed of the own vehicle and the surrounding environment (uphill, downhill, etc.).

  The measuring unit 3 measures the positional relationship between the projection position where the light spot is formed and the other vehicle based on the size of the light projection pattern formed by the plurality of light spots detected by the detecting unit 2. Here, the light projection pattern is a shape of a region on the road surface formed by connecting a plurality of light spots formed on the road surface by another vehicle having the irradiation means 4. Hereinafter, an area on the road surface surrounded by the light projection pattern may be referred to as a projection area. For example, when four light spots are formed on the road surface and a quadrangle is formed by connecting them, the region surrounded by the quadrangle is the projection region. The measuring means 3 determines the projection position of the light spot (center position of the light projection pattern) and the position of the other vehicle from the size of the light projection pattern (the distance between two predetermined light spots among the plurality of light spots). Measure the relationship. Specifically, the measuring unit 3 measures the distance from the projection position to another vehicle. As will be described later, when the irradiation unit 4 irradiates a light beam corresponding to the above positional relationship for a predetermined time instead of a light pulse, a linear light projection pattern is formed on the road surface. It is formed. In this case, the positional relationship between the projection position of the light projection pattern and another vehicle may be measured from the size of the linear light projection pattern. Here, the size of the linear light projection pattern is the length of a line segment connecting two predetermined points in the region surrounded by the light projection pattern (for example, the length of a diagonal line if the light projection pattern is a square). It is. When a plurality of light spots are formed on a straight line on the road surface, the positional relationship may be measured from the length of line segments connecting these light spots.

  The irradiation means 4 forms a plurality of light spots on the road surface by irradiating a plurality of light pulses at a predetermined time interval to a predetermined position in the traveling direction of the vehicle. As shown in FIG. 1, the irradiation unit 4 includes a beam generator 16, a beam shaping lens 17, a polarization shaper 18, and a scan actuator 19. The beam generator 16 is composed of, for example, a semiconductor laser device, and generates light having a predetermined wavelength. In the present embodiment, the beam generator 16 generates light having a wavelength in the infrared region. The beam generator 16 generates a light pulse. The beam shaping lens 17 shapes the light beam generated by the beam generator 16. The polarization shaper 18 polarizes the light beam by reflecting a part of the component perpendicular to the incident surface of the light beam output from the beam shaping lens 17. The scan actuator 19 emits the light beam polarized by the polarization shaper 18 in a desired direction. In the present embodiment, two patterns of light spots are formed by controlling the scan actuator 19 and the beam generator 16. The light generated by the beam generator 16 is not limited to light having an infrared wavelength, and may be light having any wavelength. Further, the irradiation means 4 is not limited to the above configuration, and may be any configuration as long as it forms a light spot with a predetermined pattern. The pattern of the light spot formed by the irradiating means 4 and the forming method thereof will be described later.

  The collision determination unit 5 determines a collision between the host vehicle and another vehicle based on the measurement information from the measurement unit 3. The collision determination unit 5 acquires the distance from the other vehicle to the projection position of the light spot formed by the other vehicle as the measurement information from the measurement unit 3. Then, the collision determination unit 5 determines whether or not the other vehicle and the host vehicle collide based on the host vehicle information such as the speed of the host vehicle and the distance to the detection area and the measurement information measured by the measuring unit 3. to decide. The possibility of collision is determined by comparing the distance from the host vehicle to the detection area and the distance from the other vehicle to the projection position. When the collision determination unit 5 determines that the possibility of collision is high, the collision determination unit 5 issues a warning to the driver.

  The above is the description of each part. Next, the light spot formed on the road surface by the irradiation unit 4 will be described in detail with reference to FIGS.

(Light spot formed by irradiation means)
FIG. 2 is a diagram illustrating a state in which the irradiation unit 4 irradiates the light pulse with the distance from the own vehicle to the projection position of the light spot corresponding to the size of the light projection pattern. The irradiation unit 4 forms a plurality of light spots on the road surface. As shown in FIG. 2, the irradiation means 4 forms a plurality of light spots (a1 to b2) on the road surface by irradiating a plurality of light pulses. The irradiating means 4 irradiates the light pulse with the positional relationship between the projection position of the light spot and the host vehicle 21 corresponding to the size of the light projection pattern. Specifically, the irradiation means 4 is formed by connecting a distance S (m) from the projection position of the light spot to the host vehicle 21 between two points in the light projection pattern (for example, connecting four light spots 4. A light spot is formed on the road surface so as to correspond to the length of the diagonal diagonal line d (m). For example, in FIG. 2A, the distance from the own vehicle 21 to the projection position of the light spot is S1 (m), and the size of the light projection pattern, that is, the distance between the light spots a2 and b2 is d1 (m ). On the other hand, in FIG. 2B, the distance from the host vehicle 21 to the projection position of the light spot is S2 (m), and the distance between the light spots a2 ′ and b2 ′ is d2 (m). Here, S1 / d1 and S2 / d2 are equal. That is, the irradiating means 4 has a plurality of light pulses (in FIG. 2) at predetermined time intervals so that the ratio of the distance S from the host vehicle 21 to the projection position and the diagonal length d of the light projection pattern is constant. 4) to a predetermined position in the traveling direction to form a light spot. Then, the irradiation means 4 forms a set of light spots at a predetermined distance from the host vehicle 21 as a set of a plurality of light spots (four in the above), and another set at a different position. A light spot is formed. The ratio between the distance from the host vehicle 21 to each projection position and the size of each light projection pattern is constant. Note that the ratio between the size of the light projection pattern and the distance to the projection position is not necessarily constant, and the light pulse is irradiated with the size of the light projection pattern and the projection position associated in advance with a predetermined relationship. May be.

  Next, the light spot formed on the road surface when the host vehicle 21 is tilted in the vertical direction will be described. FIG. 3 is a diagram showing a projected position of a light spot formed on the road surface when the host vehicle travels on an uneven road surface and makes a pitch motion in the vertical direction with respect to the traveling direction. FIG. 3A is a view of the direction in which the light pulse is irradiated when the host vehicle 21 does not perform the pitch motion, as viewed from the side. In addition, a plurality of light spots formed when the road surface is viewed from above are shown. As shown in FIG. 3A, when the host vehicle 21 does not perform a pitch motion, the light spot has a distance S (m) from the host vehicle 21 to the projection position of the light spot, and the light projection pattern in that case Is d (m). When the host vehicle 21 performs a pitch motion, the emission angle of the light pulse varies. Therefore, the light pulse originally irradiated to the position of the distance S from the own vehicle 21 is irradiated to a different position, and a light spot is formed. FIG. 3B is a side view of the direction in which the light pulse is irradiated when the front portion of the vehicle tilts upward due to pitch movement of the host vehicle 21. In addition, a plurality of light spots formed when the road surface is viewed from above are shown. As shown in FIG. 3B, the light pulse emitted from the host vehicle 21 is irradiated to a position away from the host vehicle 21 by S ′ (m). In this case, the size of the light projection pattern formed on the road surface is d ′ (m), which is larger than that in the case of FIG.

  Here, the emission angle of each light pulse emitted from the own vehicle 21 with respect to the own vehicle 21 (the emission angle of the own vehicle 21 with respect to the vertical direction and the horizontal direction) is constant regardless of the inclination of the own vehicle 21. Accordingly, the size d ′ of the light projection pattern increases in proportion to the distance S ′ from the host vehicle 21 to the projection position. That is, when the light spot is formed so that the ratio of the distance from the own vehicle 21 to the projection position and the size of the light projection pattern is constant in advance, the projection position is changed by the pitch movement of the own vehicle 21, Even when the size of the light projection pattern changes, the distance from the vehicle 21 to the projection position can be obtained from the size of the light projection pattern. For example, the light projection pattern size is 1 (m) at a distance of 10 (m) from the own vehicle 21 to the projection position, and the light projection is at a position of 20 (m) from the own vehicle 21 to the projection position. The irradiation unit 4 forms two sets of light spots so that the size of the pattern is 2 (m). In this case, when the front part of the host vehicle 21 is tilted upward by the pitch motion, and the light pulse that should be emitted 10 (m) ahead is formed on the road surface, it is formed on the road surface. The size of the projected light pattern is supposed to be 1 (m) but is expanded to 2 (m). Therefore, even when the host vehicle 21 is tilted due to the pitch motion, the projection position of the light spot and the size of the light projection pattern vary at the same rate due to the tilt.

  As described above, the irradiation unit 4 sets a plurality of light spots (four in the above description) as one set so that the ratio between the distance from the host vehicle to the projection position and the size of the light projection pattern is fixed in advance. A plurality of sets of light spots are formed. By mounting such an irradiating means 4 on the host vehicle and other vehicles, the host vehicle can accurately determine the position of the other vehicle by detecting a light spot formed on the road surface by the other vehicle.

  In another embodiment, the irradiating unit 4 changes the distance from the own vehicle to the projection position, and changes the arrival time until the own vehicle reaches the projection position according to the size of the light projection pattern. May be formed. The host vehicle detects the light spot formed by the other vehicle in the detection area. The distance from the own vehicle to the detection area is determined in advance. Further, the host vehicle can know the speed of the host vehicle from a vehicle speed sensor or the like. Therefore, the host vehicle can obtain the arrival time to the detection area based on the vehicle speed and the distance to the detection area. The irradiation unit 4 forms a plurality of sets of light spots at different positions on the road surface so that the ratio between the arrival time and the size of the light projection pattern is constant. For example, the irradiation unit 4 forms a light spot having a light projection pattern size of 1 (m) at a position where the host vehicle traveling at a constant speed reaches after 10 (sec), and the host vehicle is 20 (sec). ) A light spot whose light projection pattern size is 2 (m) is formed at a position that will be reached later. In this case, when the other vehicle detects the light spot of the own vehicle and the size of the light projection pattern is calculated as 1 (m), the other vehicle takes 10 hours until the own vehicle reaches the projection position. (Sec) can be calculated. Even when the host vehicle tilts in the vertical direction due to pitch movement, the arrival time can be accurately obtained from the size of the light projection pattern. That is, when the front portion of the vehicle is tilted upward by the pitch motion, the light spot is formed farther from the vehicle than the original projection position. For example, when the light spot originally formed 10 (m) ahead is formed 20 (m) ahead, the size of the light projection pattern increases in proportion to the distance, and thus the light projection formed on the road surface. The pattern is enlarged to twice the size of the light projection pattern (light projection pattern that should be formed 10 (m) ahead) when no pitch motion is performed. Further, the arrival time until reaching 20 (m) ahead is twice the time until reaching 10 (m) ahead if the speed is constant. Therefore, even when the host vehicle tilts up and down due to pitch movement, other vehicles can accurately measure the time until the host vehicle reaches the projection position of the light spot by measuring the size of the light projection pattern. Can be calculated. A collision determination can be made based on the arrival time thus obtained. The time required for the host vehicle to reach the detection area is calculated from the speed of the host vehicle and the distance to the detection area, and the time required for the other vehicle acquired by the measuring means 3 to reach the projection position is calculated. The possibility of collision is determined by comparing with the arrival time of. That is, when the time for the host vehicle and the other vehicle to reach the detection area coincides, there is a high possibility that the host vehicle and the other vehicle will collide. When the collision determination unit 5 determines that the possibility of collision is high, the collision determination unit 5 issues a warning to the driver.

  Next, the light spot pattern formed on the road surface by the plurality of light pulses emitted by the irradiation means 4 will be described. FIG. 4 is a diagram illustrating a state in which the host vehicle forms a plurality of sets of light spots at predetermined positions in the traveling direction. As shown in FIG. 4, the host vehicle 21 forms a plurality of light spots (a1 to an and b1 to bn) at predetermined positions on the course. The irradiation unit 4 irradiates a plurality of light pulses at a predetermined time interval. Therefore, a plurality of light spots are formed on the road surface in order. In the present embodiment, a light spot having a pattern formed from the left side to the right side when viewed from the host vehicle in the order of the light spot a1 to an by the method described later (hereinafter referred to as a right-scanning light spot) and the light spot b1. In the order of bn, a light spot having a pattern formed from the right side to the left side when viewed from the host vehicle (hereinafter referred to as a left-scanning light spot) is formed. As shown in FIG. 4, the right scan and left scan light spots are arranged on different straight lines, and the direction of the trajectory connecting the right scan light spots in the irradiation order is the trajectory connecting the left scan light spots in the irradiation order. A light spot is formed so as to be opposite to the direction. Each straight line is parallel to each other and is perpendicular to the traveling direction of the vehicle. The other vehicle having the own vehicle and the irradiation means 4 travels while forming the light spot having the above pattern on the road surface. And the own vehicle detects the light spot of the said pattern which the other vehicle formed on the road surface using the detection means 2. FIG.

  FIG. 5 is a diagram showing how the host vehicle obtains the distance from the other vehicle to the projection position of the light spot by detecting the light spot formed by the other vehicle in the detection region R. The own vehicle 21 can measure the distance by measuring the size of the light projection pattern of the light spot formed by the other vehicle 22. Even when the other vehicle 22 travels on an uneven road surface and makes a pitch movement in the vertical direction with respect to the traveling direction, the own vehicle 21 can measure the size of the light projection pattern to The distance from 22 to the projection position of the light spot can be accurately measured.

  Next, a method for forming the right and left scan light spots formed by the irradiation unit 4 will be described. The irradiation unit 4 controls the scan actuator 19 and the beam generator 16 to form the light spot having the above pattern on the road surface. The scan actuator 19 is configured by a galvanometer mirror, for example. By controlling the galvanometer mirror, the emission direction of the light pulse can be controlled, and the light spot having the above pattern can be formed at a predetermined position on the road surface. A polygon mirror may be used as the scan actuator 19. Hereinafter, a method for forming light spots for right scanning and left scanning using a polygon mirror will be described.

  With reference to FIG. 6A to FIG. 7, the light spots of the right scan and left scan patterns formed by the irradiation unit 4 will be described. 6A and 6B are diagrams showing a detailed configuration of the scan actuator 19. 6A is a view of the scan actuator 19 as viewed from the side, and FIG. 6B is an end view taken along the line AA of the scan actuator 19 taken along a plane parallel to the lower surface. 6A and 6B (and FIG. 7), the left side of the figure corresponds to the front of the vehicle. As shown in FIGS. 6A and 6B, the scan actuator 19 includes a polygon mirror 61 and a reflecting mirror 62. The polygon mirror 61 has a frustum shape composed of an upper surface, a lower surface, and six side surfaces 61a to 61f. From the side surface 61a to the side surface 61f, planes and polygonal surfaces (called approximate curved surfaces) formed by a large number of planes are alternately arranged. That is, as shown in FIG. 6B, the side surfaces 61a, 61c, and 61e are configured by planes, and the side surfaces 61b, 61d, and 61f are configured by approximate curved surfaces. Here, the side surfaces 61a, 61c, and 61e configured by planes are referred to as A regions, and the side surfaces 61b, 61d, and 61f configured by approximate curved surfaces are referred to as B regions. Further, the polygon mirror 61 rotates clockwise around the rotation shaft 61g. The curvature of the approximate curved surface of the region B is a circumscribed circle of a hexagon (a hexagon having three sides of the side surfaces 61a, 61c and 61e in FIG. 6B and three sides of the broken line) formed by the side surface with the rotation axis 61g as the center. Is set larger than the curvature of. The polygon mirror 61 is not limited to the above configuration, and may have any shape as long as it has an A region and a B region on the side surface. For example, the polygon mirror 61 may have an octagonal upper surface and lower surface and eight side surfaces. Good. In addition, the A region and the B region are not necessarily arranged alternately.

  The light pulse generated from the beam generator 16 is reflected by the reflecting mirror 62 and enters one side surface of the polygon mirror 61, for example, the side surface 61a. The light pulse incident on the side surface 61a is reflected on the side surface 61a and emitted forward of the vehicle. Here, the angle γ of each side surface 61a to 61f with respect to the vehicle vertical direction is set to be different for each side surface 61a to 61f. Therefore, the light pulse reflected from each side surface is irradiated to different positions in front of the vehicle. For example, when the angle of the side surface 61c is set larger than the angle of the side surface 61a, the light pulse reflected by the side surface 61c is irradiated farther than the light pulse reflected by the side surface 61a. In this way, by adjusting the angle γ of each side surface 61 with respect to the vertical direction, a light spot is formed at a predetermined distance in front of the vehicle. Next, the light spot pattern formed by the irradiation unit 4 when the polygon mirror 61 is rotated will be described.

  FIG. 7 is a diagram illustrating a light spot pattern formed when the polygon mirror 61 is rotated. (Aa) to (Ac) in FIG. 7 show that incident light (dashed line) is a polygon when a plurality of light pulses are generated from the beam generator 16 according to the rotation angle of the polygon mirror 61 (three pulses in the figure). This shows the direction in which the reflected light (solid arrow) is emitted when reflected by one surface of the A region of the mirror 61. As shown in (Aa) to (Ac) of FIG. 7, the reflection direction of the light pulse reflected in the A region changes in the same direction as the rotation direction of the polygon mirror 61. A light spot is formed on the road surface by a plurality of light pulses reflected by one surface of these A regions. These light spots are formed on a substantially straight line from the left to the right as viewed from the vehicle. This is the right scanning light spot.

  On the other hand, the light pulse reflected in the B region is emitted in the direction as indicated by (Ba) to (Bc) in FIG. 7B to 7B, when a plurality of light pulses are generated from the beam generator 16 in accordance with the rotation angle of the polygon mirror 61 (here, three pulses), the incident light (broken line) is converted to the polygon mirror. This shows the direction in which the reflected light (solid arrow) is emitted when it is reflected by one surface of the 61-B region. As shown in FIG. 7 (Ba), the region B is a substantially curved surface whose curvature is larger than that of the hexagonal circumscribed circle, and therefore incident light is reflected in the opposite direction to (Aa). Similarly in (Bc), the incident light is reflected in the opposite direction to (Ac). That is, the reflection direction of the light pulse reflected in the region B changes in the direction opposite to the rotation direction of the polygon mirror 61. A light spot is formed on the road surface by a plurality of light pulses reflected by one surface of these B regions. These light spots are formed on a substantially straight line from the right to the left as viewed from the vehicle. This is the light spot of the left scan.

  As described above, by configuring the scan actuator 19, the light spot having the right scan pattern and the left scan pattern shown in FIG. 4 is formed. Then, with these two patterns of light spots as one set, a plurality of sets of light spots are formed in association with the projection positions and the size of the light projection pattern.

(Calculation method of light projection pattern size)
Next, a method in which the measurement unit 3 calculates the size of the light projection pattern from the light spot detected by the detection unit 2 will be described with reference to FIGS. In this method, the size of the light projection pattern is calculated by obtaining the detection time interval of each light spot caused by the optical path difference of light.

  FIG. 8 is a diagram illustrating a state in which a plurality of right-scanning light pulses emitted by the other vehicle 22 are reflected by the detection area of the host vehicle 21 and detected by the host vehicle 21. As shown in FIG. 8, the other vehicle 22 emits three light pulses at predetermined time intervals as light pulses for right scanning. Here, the time interval of the three light pulses to be irradiated is β (sec). The first light pulse emitted from the other vehicle 22 forms a light spot a1 on the road surface and is reflected by the road surface. The reflected light pulse is detected by the host vehicle 21. The first light pulse travels a distance Sa1 (m) from the other vehicle 22 to the position of the light spot a1 and a distance La1 (m) from the light spot a1 to the host vehicle 21. Therefore, the first light pulse is detected by the host vehicle 21 after the distance Sa1 + La1 travels the distance Sa1 + La1 from the time when it is emitted from the other vehicle 22. A second light pulse is emitted β (sec) after the first light pulse is emitted. The second light pulse is emitted from the other vehicle 22, travels a distance Sa2 (m), and then forms a light spot a2. The second light pulse is detected by the host vehicle 21 after traveling the distance La2 (m). Accordingly, the second light pulse is detected by the host vehicle 21 with a delay of the distance that light travels the distance Sa2 + La2 from the time when it is emitted from the other vehicle 22. Further, the third light pulse is also emitted β (sec) after the second light pulse. Similarly, since the third light pulse travels the distance Sa3 (m) and the distance La3 (m) until it forms the light spot a3 and is detected by the own vehicle 21, the time from the time when it is emitted from the other vehicle 22 is reached. It is detected by the host vehicle 21 with a delay of the distance Sa3 + La3 by the time the light travels. Thus, the three light pulses emitted from the other vehicle 22 are detected by the host vehicle 21 with a slight delay from the emission time. Therefore, the time intervals of the three light spots detected by the host vehicle 21 are different from the time interval β.

FIG. 9 is a diagram schematically showing a delay in time from when the three light pulses of the right scan are emitted until they are detected by the host vehicle 21. In FIG. 9, the vertical axis indicates the light intensity, and the horizontal axis indicates time. FIG. 9A shows the time when three light pulses are emitted from the other vehicle 22. FIG. 9B shows the time when the three light pulses emitted from the other vehicle 22 are reflected on the road surface. FIG. 9C shows the time at which three light pulses emitted from the other vehicle 22 are detected by the host vehicle 21. First, the other vehicle 22 emits a light pulse that forms a light spot a1 (FIG. 9A). The light spot a1 is formed on the road surface with a delay by the time that the light travels the distance Sa1 (FIG. 9B). And the own vehicle 21 detects a light pulse further delayed by the time when the light travels the distance La1 (FIG. 9C). Accordingly, when the time when the light pulse forming the light spot a1 is emitted is 0, the host vehicle 21 detects the light spot a1 at time (Sa1 + La1) / c. Here, c is the speed of light. Similarly, the light spot a2 is detected at time β + (Sa2 + La2) / c. Similarly, the light spot a3 is detected at time 2β + (Sa3 + La3) / c. Accordingly, the detection time interval Δta1 between the light spot a1 and the light spot a2 is Δta1 = β− (La1−La2) / c + (Sa2−Sa1) / c. Similarly, the detection time interval Δta2 between the light spot a2 and the light spot a3 is Δta2 = β− (La2−La3) / c + (Sa3−Sa2) / c. Here, when the distance from the other vehicle 22 to the projection position of the light spot is sufficiently larger than the distance between the light spots (the distance between a1 and a2), the difference between the distance Sa1 and the distance Sa2 can be ignored. . Therefore, the detection time interval Δta1 is obtained by the following equation (1).
Δta1 = β− (La1−La2) / c Formula (1)
Similarly, the detection time interval Δta2 is obtained by the following equation (2).
Δta2 = β− (La2−La3) / c Formula (2)

FIG. 10 is a diagram illustrating a state in which a plurality of left-scanning light pulses irradiated by the other vehicle 22 are reflected by the detection region of the host vehicle 21 and detected by the host vehicle 21. FIG. 11 is a diagram schematically illustrating a delay in time from when the three light pulses of the left scan are emitted until they are detected by the host vehicle 21. In FIG. 11, as in FIG. 9, the vertical axis indicates the light intensity, and the horizontal axis indicates the time. Also in FIG. 10, each light pulse is detected by the host vehicle 21 with a delay from the time when each light pulse is emitted, as in the above-described right scanning light spot. Similar to the method described above, the detection time interval Δtb1 between the light spot b1 and the light spot b2 is obtained by the following equation (3).
Δtb1 = β + (Lb2−Lb1) / c Equation (3)
Further, the detection time interval Δtb2 between the light spot b2 and the light spot b3 is obtained by the following equation (4).
Δtb2 = β + (Lb3−Lb2) / c Formula (4)

FIG. 12 shows the detection time intervals obtained from the above equations (1) to (4). FIG. 12 is a diagram illustrating the relationship between the light spot detection time interval and the detection time in the first embodiment. In FIG. 12, the vertical axis represents the light spot detection time interval Δt, and the horizontal axis represents time. For example, the detection time interval Δta1 between the light spot a1 and the light spot a2 is plotted as shown in FIG. 12, with the detection time of the light spot a2 as the time on the horizontal axis and Δta1 as the value on the vertical axis. As shown in FIG. 12, the detection time interval Δta of the right scanning light spot is plotted on a substantially straight line at a position slightly shifted from the irradiation time interval β of the light pulse. The detection time interval Δtb of the light spot of the left scan is also plotted on a substantially straight line at a position slightly shifted from the irradiation time interval β of the light pulse. Further, the detection time interval Δta of the right scanning light spot is smaller than the detection time interval Δtb of the left scanning light spot. This time interval difference increases as the distance between the right and left light spots increases. That is, when the difference between Δta1 and Δtb1 is Δtab1, and the difference between Δta2 and Δtab2 is Δtab2, Δtab1 and Δtab2 are expressed by the following equations (5) and (6) from equations (1) to (4). Desired.
Δtab1 = (La1−Lb1) / c Equation (5)
Δtab2 = (Lb3-La3) / c Equation (6)
Here, La2 and Lb2 are assumed to be equal. The distance between the straight line connecting the right scanning light spot and the straight line connecting the left scanning light spot is compared with the distance from the other vehicle 22 to the projection position and the distance from the own vehicle 21 to the projection position. Is considered small enough. Then, the difference between the distance d2 between the right-scanning light spots and the distance d2 ′ between the left-scanning light spots can be ignored. In this case, La1 and Lb3 are approximately equal, and Lb1 and La3 are approximately equal. That is, Δtab1 and Δtab2 are substantially equal. Accordingly, the time interval difference Δtab1 indicates the difference between La1 and La3, that is, the time during which light travels the distance 2 · d2 between the light spots La1 and La3, as is apparent from the equation (5). Therefore, the distance between the light spots (the size of the light projection pattern) can be calculated by plotting the detection time interval of each light spot as shown in FIG. 12 and obtaining the time interval difference between the right scan and the left scan. it can. Since the host vehicle 21 is traveling at a certain speed, the host vehicle 21 travels at the distance that the host vehicle 21 travels during the time when the light travels between the light spots and the time from when the right scan to the left scan light spot is formed. It is necessary to correct the distance traveled by the vehicle 21 and calculate the distance between the light spots.

  In addition, since the magnitude | size of a light projection pattern is predetermined, the said time interval difference has an upper limit. When the own vehicle 21 detects a set of light spots with the longest distance from the other vehicle 22 to the projection position, the time interval difference is maximized. When the front of the vehicle is tilted upward due to the pitch movement of the other vehicle 22, the other vehicle 22 may form a light spot at a position farther than the farthest set of light spots. When the vehicle 21 detects this light spot, the size of the light projection pattern is larger than the upper limit value. Therefore, when the size of the light projection pattern of the detected light spot is larger than the upper limit value, the other vehicle 22 exists at a position very far from the projection position, and the own vehicle 21 and the other vehicle 22 may collide. Therefore, the host vehicle 21 may determine that it does not collide.

  Further, the distance between the light spots may be calculated based on the detection time interval of the light spot of the right scan or the left scan represented by the expressions (1) to (4). For example, Δta1 expressed by Equation (1) changes according to the distance d2 between the light spots La1 and La2, and thus the size of the light projection pattern can be calculated by obtaining Δta1.

  The light spot detection time interval Δt can be obtained, for example, as follows. FIG. 13 is a diagram showing a method of obtaining the light spot detection time. In this method, the light pulse incident on the detection means 2 is split into two and received by each photodiode. The two photodiodes are masked alternately with a predetermined period. For example, the mask cycle is set to 10 (nsec). FIG. 13A is a diagram showing emitted light pulses. The vertical axis represents light intensity, and the horizontal axis represents time. As shown in FIG. 13A, the emitted light pulse actually has a spread over a certain period of time. FIG. 13B is a diagram showing the mask timing of each photodiode. Masking is performed when ON and light is received when OFF. FIG. 13C is a diagram showing light received by each photodiode. The light pulse incident on the detection means 2 is received by two photodiodes. Since the two photodiodes are masked alternately, as shown in FIG. 13C, each photodiode receives only light corresponding to the unmasked time of the light pulse. Therefore, the light reception timing t can be obtained by obtaining the triangular area ratio of the photodiode 1 and the photodiode 2 shown in FIG. In FIG. 13, since the areas of the two triangles are equal, it can be seen that the light pulse was received in a half period of the mask. In this manner, the light reception timing of each light spot can be obtained, and the light spot detection time interval Δt can be obtained from the difference in the light reception timing of each light spot. In another method, the detection time interval of each light spot may be obtained by accurately measuring the detection time of each light spot.

  As described above, the size of the light projection pattern can be obtained from the time interval difference between the light spots, and the distance from the projection position of the light spot to the other vehicle 22 can be obtained from the size of the light projection pattern. Whether or not the own vehicle 21 and the other vehicle 22 collide can be determined based on the obtained distance (or arrival time).

  In the present embodiment, it is assumed that the angle of the traveling direction of the other vehicle 22 with respect to the traveling direction of the own vehicle 21 is a right angle as shown in FIG. 8, but there is an angle between the own vehicle 21 and the other vehicle 22. When traveling with θ, since the distance from the own vehicle 21 to each light spot is different, the time interval difference varies with the angle θ. Therefore, it is necessary to obtain the angle θ between the host vehicle 21 and the other vehicle 22 and correct the change caused by the angle θ. The angle θ between the host vehicle 21 and the other vehicle 22 is obtained, for example, by a shift in the detection time interval of each light spot. A method for obtaining the angle θ will be described later.

  The light projection pattern formed on the road surface by the other vehicle 22 is not a spot-like light spot, but a light beam locus is drawn by continuously irradiating the light beam, and the linear pattern formed on the road surface. This pattern may be used. Further, the projection area may be formed by irradiating light on the entire projection area instead of the spot-like light spot.

  Further, it may be a light blank projection pattern formed by shielding a part of light instead of the light spot. The other vehicle 22 irradiates light partially shielded (such as a headlight), and forms an area where light is irradiated and an area where no light is irradiated (light blank area) on the road surface. This formed light blank region is a light blank projection pattern. Further, the light blank projection pattern may be a light blank spot formed by a dotted blank region.

  In this embodiment, the size of the light projection pattern is calculated from the light spot detection time interval. However, the size of the light projection pattern may be calculated by another method. For example, the distance between light spots formed on the road surface may be calculated using a distance image technique.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. Since the periphery monitoring device according to the second embodiment has the same configuration as the periphery monitoring device 1 according to the first embodiment, description thereof is omitted.

  In the second embodiment, the light projection pattern formed by the irradiation unit 4 is different from that of the first embodiment. FIG. 14 is a diagram showing a light spot pattern formed by the irradiation means in the second embodiment. As shown in FIG. 14, the irradiation unit 4 irradiates the light pulse so that each light spot is formed on the circumference of a circle having a predetermined radius. The irradiating means 4 forms a plurality of sets of light spots at different positions on the road surface with the light spots forming a circle as a set of light spots. As in the first embodiment, each set is set so that the ratio between the projection position of the light spot (the center of the circle formed by the light spot) and the size of the light projection pattern (the radius r of the circle) is constant. Light spots are formed. As described above, since the light spot is formed on the circumference, even when the host vehicle 21 and the other vehicle 22 are traveling at a certain angle θ (the host vehicle 21 is at the position P2), the light spot is related to the angle θ. Therefore, the size of the light projection pattern can be obtained. Details will be described below. The light spot having such a pattern can be formed by using a galvanometer mirror as the scan actuator 19.

  FIG. 15 is a diagram showing how the other vehicle 22 forms a right-scanning light spot and a left-scanning light spot on the circumference, and the own vehicle 21 detects the light spot. The other vehicle 22 forms a right scanning light spot (a1 to an) counterclockwise on the circumference of the circle C from the left side to the right side of the other vehicle 22, and the left scanning light spot (b1 to bn). Is formed counterclockwise on the circumference of the circle C from the right side to the left side of the other vehicle 22. For the sake of explanation, it is assumed that the host vehicle 21 is at the position P1 (the host vehicle 21 and the other vehicle 22 are at right angles). The first light spot a1 of the right scan is formed at the intersection of the circle C and a straight line that passes through the center O of the circle C and is perpendicular to the traveling direction of the other vehicle 22. The nth light spot an in the right scan is formed at the intersection on the opposite side to a1. The first light spot b1 in the left scan is formed at the position of the light spot an, and the nth light spot bn in the left scan is formed at the position of the light spot a1.

  The distance from the light spots a1 and bn to the other vehicle 22 is S, and the distance from the light spots a1 and bn to the host vehicle 21 is L. The first light pulse of the right scan emitted from the other vehicle 22 travels the distance S and the distance L, and then is received by the host vehicle 21. Therefore, the first light pulse is received by the host vehicle 21 after (S + L) / c (sec) from the other vehicle 22.

The second light pulse of the right scan forms a light spot a2 on the circumference of the circle C. Let τ be the angle formed by the line segment connecting the light spot a1 and the center O and the line segment connecting the light spot a2 and the center O. The distance from the other vehicle 22 to the light spot a2 is S ′, and the distance from the light spot a2 to the host vehicle 21 is L ′. The second light pulse of the right scan emitted from the other vehicle 22 travels the distance S ′ and the distance L ′, and then is received by the host vehicle 21. Accordingly, the second light pulse is emitted after β (sec) from the emission of the first light pulse, and after being emitted from the other vehicle 22 (S ′ + L ′) / c (sec), the host vehicle 21. Is received. Here, the distance S ′ and the distance L ′ are obtained by the following equations (7) and (8).
S ′ = S−r · sinτ Equation (7)
L ′ = L− (r−r · cos τ) Equation (8)
Thus, the second light pulse is received by the host vehicle 21 after being delayed from the other vehicle 22 by the time indicated by the following equation (9).
(S + L−r · (sin τ−cos τ + 1)) / c (sec) Equation (9)
Therefore, the detection time interval Δta1 between the light spots a1 and a2 can be obtained by the following equation (10).
Δta1 = β−r · (sin τ−cos τ + 1)) / c Equation (10)
Similarly, the light spot a <b> 3 is received by the host vehicle 21 after being delayed from the other vehicle 22 by a time indicated by the following formula (11).
(S + L−r · (sin τ ₂ −cos τ ₂ +1)) / c (sec) Equation (11)
However, τ ₂ is an angle formed by a line segment connecting the light spot a1 and the center O and a line segment connecting the light spot a3 and the center O. Therefore, the detection time interval Δta2 between the light spots a3 and a2 can be obtained by the following equation (12).
Δta2 = β−r · ((sin τ ₂ −cos τ ₂ ) − (sin τ−cos τ)) / c Equation (12)
Similarly, the detection times of the light spots a4 to an and b1 to bn are obtained, and the detection time interval Δt of each light spot is calculated. As apparent from the equations (10) and (12), the detection time interval Δt is a periodic function having the radius r of the circle C as an amplitude. Therefore, when the detection time interval Δt calculated in this way is plotted in the figure, a curve as shown in FIG. 16 is drawn. FIG. 16 is a diagram illustrating the relationship between the light spot detection time interval and the detection time in the second embodiment. In FIG. 16, the horizontal axis indicates the time, and the vertical axis indicates the detection time interval. The amplitude of the curve obtained in this way depends on the radius r of the circle C. Therefore, the radius r of the circle C can be obtained by obtaining the magnitude of the amplitude.

  Next, a case where the host vehicle 21 is at the position P2 in FIG. 15 will be described. When the host vehicle 21 is at the position P2, the host vehicle 21 and the other vehicle 22 are traveling at an angle θ different from a right angle. When the own vehicle 21 at the position P2 detects the light spot formed by the other vehicle 22, the detection time interval Δt of each light spot changes from the difference in the optical path length of the light as described above. When the host vehicle 21 at the position P2 sees the light spot, the light spot is formed on the circle C. Therefore, the light spot appears to be formed in the same arrangement as that at the position P1. That is, if the irradiation order of each light spot is ignored, the light spot formed on the circumference looks the same from any angle. Therefore, as described above, when the detection time interval Δt of each light spot is obtained and plotted on a graph, a curve as shown in FIG. 16 is obtained. And the radius r of the circle C can be calculated | required by calculating | requiring the magnitude | size of the amplitude of the obtained curve. Note that when the host vehicle 21 and the other vehicle 22 have an angle θ different from a right angle, the curve shown in FIG. 16 is shifted to the right or left. That is, since the light spots are formed in the order of a1 to an and b1 to bn, as shown in FIG. 15, the start point is different between the case where the host vehicle 21 is at the position P1 and the case where the own vehicle 21 is at the position P2. Here, the starting point refers to a position where the light spot a1 viewed from the host vehicle 21 is formed.

  As described above, the radius r of the circle C, that is, the size of the light projection pattern can be obtained by obtaining the detection time interval Δt of each light spot and obtaining the magnitude of the amplitude of the detection time interval Δt. . Thus, regardless of the angle θ between the host vehicle 21 and the other vehicle 22, the host vehicle 21 obtains the distance from the other vehicle 22 to the projection position (or the arrival time until the other vehicle 22 reaches the projection position). be able to. Even when the other vehicle 22 is tilted in the vertical direction, the host vehicle 21 can determine the distance from the other vehicle 22 to the projection position.

  In this embodiment, the light spot is formed on the circumference, but may be formed on an ellipse. Even when the light spot is formed on an ellipse, the detection time interval Δt of each light spot becomes a periodic function, and the magnitude of the light projection pattern can be obtained by obtaining the magnitude of the amplitude of the function. Further, in FIG. 15, a semicircle of a circle C is drawn for each of the light spots a1 to an for the right scan and the light spots b1 to bn for the left scan, but a part of the circle is drawn as shown in FIG. May be.

  Further, as in the first embodiment, the light pattern formed on the road surface by the other vehicle 22 may be a pattern in which a circle is drawn in a linear shape instead of a dotted light spot. In addition, a circular projection region may be formed by irradiating light on the entire projection region, not a point-like light spot. Moreover, you may form the said pattern by an optical blank area | region similarly to 1st Embodiment.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. Since the periphery monitoring device according to the third embodiment has the same configuration as the periphery monitoring device 1 according to the first embodiment, the description thereof is omitted.

  In the third embodiment, the light projection pattern formed by the irradiation unit 4 is different from that of the first embodiment. FIG. 17 is a diagram showing a light spot pattern formed by the irradiation means in the third embodiment. As shown in FIG. 17, the right-scanning light spot and the left-scanning light spot are formed obliquely with respect to the traveling direction of the host vehicle 21. Accordingly, the angle θ between the host vehicle 21 and the other vehicle 22 can be obtained based on the shape of the region (light projection pattern) formed by connecting the light spots as viewed from the host vehicle 21. That is, as shown in FIG. 17, the other vehicle 22 travels while forming a plurality of light spots on the road surface with a plurality of light spots as one set. The shape of the light projection pattern formed by each set of light spots is the same regardless of the distance from the other vehicle 22, and its size increases in proportion to the distance from the other vehicle 22. Therefore, since the shape of the light projection pattern seen from the own vehicle 21 differs depending on the angle θ between the own vehicle 21 and the other vehicle 22, the shape of the light projection pattern seen from the own vehicle 21 (the inclination of the light projection pattern) is obtained. Thus, the angle θ can be obtained. Such a light spot pattern can be formed by a galvanometer mirror. It can also be formed by combining a galvanometer mirror and a polygon mirror.

  In this embodiment, the light spot is formed in the arrangement as shown in FIG. 17, but the light spot may be formed in the arrangement as in the first embodiment (see FIG. 4). Good. That is, as in the first embodiment, the right scan and left scan light spots are arranged in a straight line, and the direction of the trajectory connecting the right scan light spots in the irradiation order is the trajectory connecting the left scan light spots in the irradiation order. A light spot may be formed so as to be opposite to the direction of.

  In the present embodiment, each light spot is detected, and the angle θ between the host vehicle 21 and the other vehicle 22 is obtained based on the detected time interval of each light spot. Hereinafter, a method for obtaining the angle between the host vehicle 21 and the other vehicle 22 will be described in detail.

  FIG. 18 is a diagram illustrating a state in which the own vehicle 21 detects a light spot formed by the other vehicle 22 when the own vehicle 21 and the other vehicle 22 are traveling at a certain angle θ. As shown in FIG. 18, when the other vehicle 22 irradiates four light pulses at a time interval β, four light spots are formed on the road surface in the order of a1, a2, b1, and b2. The distance from the light spot a1 to the other vehicle 22 is Sa1 (m), and the distance from the light spot a1 to the host vehicle 21 is La1 (m). Similarly, the distance from the light spot a2 to the other vehicle 22 is Sa2 (m), and the distance to the host vehicle 21 is La2 (m). Further, the distance from the light spot b1 to the other vehicle 22 is Sb1 (m), the distance from the own vehicle 21 is Lb1 (m), the distance from the light spot b2 to the other vehicle 22 is Sb2 (m), and the own vehicle 21 Is the distance Lb2 (m). In such a case, each light pulse is delayed by a time corresponding to each optical path length from when each light pulse is emitted from the other vehicle 22 until it is detected by the own vehicle 21.

FIG. 19 is a diagram schematically illustrating a time delay from when each light pulse is emitted from the other vehicle 22 to when it is detected by the host vehicle 21. In FIG. 19, the horizontal axis indicates time, and the vertical axis indicates light intensity. As shown in FIG. 19, the time at which each light spot is detected is delayed by the time it travels through each optical path length after each light pulse is emitted. Accordingly, the detection time interval Δt of each light spot is different from the time interval β at which the light pulse is irradiated. When the detection time interval between the light spots a1 and a2 is Δt1, the detection time interval between the light spots a2 and b1 is Δt2, and the detection time interval between the light spots b1 and b2 is Δt3, the following equations (13) to ( 15).
Δt1 = β + (La2−La1 + Sa2−Sa1) / c = β + A Formula (13)
Δt2 = β + (Lb1−La2 + Sb1−Sa2) / c = β + B Formula (14)
Δt3 = β + (Lb2−Lb1 + Sb2−Sb1) / c = β + C Formula (15)
However, A = (La2−La1 + Sa2−Sa1) / c, B = (Lb1−La2 + Sb1−Sa2) / c, and C = (Lb2−Lb1 + Sb2−Sb1) / c. From the equations (13), (14), (14), and (15), the following equations (16) and (17) are obtained.
A + B = (Lb1-La1 + Sb1-Sa1) / c Formula (16)
B + C = (Lb2-La2 + Sb2-Sa2) / c Formula (17)

In the above equation (16), when A + B = 0, the following equation (18) is obtained.
La1-Lb1 = Sb1-Sa1 Formula (18)
Here, the distance Sa1 and the distance Sb1 are always constant regardless of the position of the host vehicle 21. That is, when A + B = 0, the difference between the distance La1 from the host vehicle 21 to the light spot a1 and the distance Lb1 from the host vehicle 21 to the light spot b1 is always constant. Therefore, when A + B = 0 is satisfied, the host vehicle 21 exists at a position where the difference between the distance La1 from the host vehicle 21 to the light spot a1 and the distance Lb1 from the host vehicle 21 to the light spot b1 is constant. Become.

ここで、Ｓｂ１−Ｓａ１＝ｄ１（ｍ）とした。上記式（１９）をｘについて解くと、以下の式（２０）が得られる。

式（２０）から明らかなように、Ａ＋Ｂ＝０を満たす点、すなわち、Ｌａ１とＬｂ１との差が一定である点（ｘ，ｙ）は、曲線を描く。ここで、上記式（２０）において、４ｄ１²ｙ²／（ｄ²−ｄ１²）がｄ１²に比べて十分に大きい範囲では、ｄ１²は無視できるため、式（２０）は以下の式（２０’）に近似できる。

式（２０’）より、ｙが大きい範囲では、Ａ＋Ｂ＝０を満たす点の集合は直線になる。ｄ１及びｄは、光投影パターンの大きさを示しており、ｙは、２つの光スポットを結んだ線分から自車両２１までの距離を示している。自車両２１は、自車両２１の検出領域で他車両２２の光スポットを検出する。通常、自車両２１から検出領域まではある程度離れており、自車両２１から検出領域までの距離は、光投影パターンの大きさ（所定の光スポット間の距離ｄ）に比べて十分に大きい。従って、他車両２２の光スポットを検出した自車両２１は、式（２０’）を満たす直線上に位置することになる。図２０では、式（２０’）により求められたＡ＋Ｂ＝０を満たす直線が矢印で示されている。図２０に示されるように、ｙが正の場合と負の場合とでｘ軸に対称な２本の直線が示されている。また、このようにして求められたＡ＋Ｂ＝０を満たす直線が、図１８において示されている。 Next, the position of the host vehicle 21 that satisfies A + B = 0 is obtained. FIG. 20 is a diagram showing a point (x, y) that satisfies A + B = 0. Here, it is assumed that the distance between the light spot a1 and the light spot b1 is d (m). The light spot a1 is located at the origin, and the light spot b1 is located at the coordinates (d, 0). The point (x, y) at which La1-Lb1 is constant satisfies the following formula (19).

Here, Sb1−Sa1 = d1 (m). When the above equation (19) is solved for x, the following equation (20) is obtained.

As is clear from the equation (20), a point satisfying A + B = 0, that is, a point (x, y) where the difference between La1 and Lb1 is constant draws a curve. Here, in the above formula (20), the sufficiently large range compared to ^{4d1 2 y 2 / (d 2} -d1 2) is d1 ^2, since the d1 ² negligible, the equation (20) the following formula ( 20 ′).

From the equation (20 ′), in a range where y is large, a set of points satisfying A + B = 0 is a straight line. d1 and d indicate the size of the light projection pattern, and y indicates the distance from the line segment connecting the two light spots to the host vehicle 21. The own vehicle 21 detects the light spot of the other vehicle 22 in the detection area of the own vehicle 21. Usually, the own vehicle 21 is far away from the detection area to some extent, and the distance from the own vehicle 21 to the detection area is sufficiently larger than the size of the light projection pattern (distance d between predetermined light spots). Accordingly, the host vehicle 21 that has detected the light spot of the other vehicle 22 is positioned on a straight line that satisfies the equation (20 ′). In FIG. 20, a straight line satisfying A + B = 0 obtained by the equation (20 ′) is indicated by an arrow. As shown in FIG. 20, two straight lines symmetric with respect to the x-axis are shown when y is positive and negative. Further, a straight line satisfying A + B = 0 obtained in this way is shown in FIG.

The angle between the straight line and the straight line connecting the light spot a1 and the light spot b1 can be obtained from the slope of the straight line obtained by the above equation (20 ′). D1 is the difference between the distance Sb1 from the other vehicle 22 to the light spot b1 and the distance Sa1 from the other vehicle 22 to the light spot a1 (from equation (19)). In FIG. 18, since the distance from the other vehicle 22 to the projection position is sufficiently longer than the distance between the light spot a1 and the light spot b1 in the left-right direction of the other vehicle 22, d1 is the light spot a1 and the light spot b1. The distance d1 ′ in the traveling direction of the other vehicle 22 is substantially equal. D is the distance between the light spot a1 and the light spot b1. Here, the other vehicle 22 has a plurality of sets so that the ratio between the size of the light projection pattern and the distance from the other vehicle 22 to the projection position of the light spot (or the arrival time to reach the projection position) is constant. The light spot is formed. Therefore, the ratio between d1 and d is always constant. Further, even when the other vehicle 22 is tilted in the vertical direction by the pitch motion and the projection position of the light spot is changed, the ratio between d1 and d does not change. That is, in the equation (20 ′), d1 ² / (d ² −d1 ² ), which is a coefficient of y, is always constant regardless of the value of d1 or d. Therefore, the slope of the straight line obtained by the equation (20 ′) is constant regardless of the size of the light projection pattern. On the other hand, since the other vehicle 22 forms a plurality of light spots in the same arrangement irrespective of the projection position (only the size is different), a straight line connecting the light spot a1 and the light spot b1 with respect to the traveling direction of the other vehicle 22 The angle of is constant.

  Therefore, the angle θ between the host vehicle 21 and the other vehicle 22 when A + B = 0 is satisfied is constant regardless of the projection position of the light spot, and the host vehicle 21 knows this angle in advance. That is, the host vehicle 21 can determine the angle θ between the host vehicle 21 and the other vehicle 22 when A + B = 0. Further, when A + B <0, Sa1 + La1> Sb1 + Lb1 is established, and therefore the own vehicle 21 exists on the left side (the other vehicle 22 side) of the straight line satisfying A + B = 0 in FIG. Further, when A + B> 0, the host vehicle 21 exists on the right side of the straight line satisfying A + B = 0 (the opposite side of the other vehicle 22).

  Further, it is possible to determine whether the other vehicle 22 is approaching from the right side of the own vehicle 21 or approaching from the left side based on the value of C shown in Expression (15). That is, when C> 0, Lb2> Lb1 + Sb1-Sb2. The difference between Sb1 and Sb2 is sufficiently smaller than the difference between Lb1 and Lb2. Accordingly, in this case, since the distance from the own vehicle 21 to the light spot b2 is larger than the distance from the own vehicle 21 to the light spot b1, the other vehicle 22 exists on the left side of the own vehicle 21 (the own vehicle 21 is It can be seen that they are present on the left side of a straight line equidistant from the light spots b1 and b2. Conversely, when C <0, it can be seen that the other vehicle 22 exists on the right side of the host vehicle 21. Further, when C = 0, the host vehicle 21 exists at substantially the same position from the light spot b1 and the light spot b2, that is, on the vertical bisector connecting the light spot b1 and the light spot b2. Accordingly, in this case, the host vehicle 21 is traveling facing the other vehicle 22 or traveling in parallel with the other vehicle 22. Then, from the value of C, it can be seen which of the two straight lines satisfying A + B = 0 shown in FIG. That is, in the case of A + B = 0, when the value of C is close to 0, the host vehicle 21 exists on a straight line indicated by an arrow that is parallel to the traveling direction of the other vehicle 22. Therefore, the angle θ between the host vehicle 21 and the other vehicle 22 can be obtained.

  As described above, based on the time lag between the detection time interval Δt of each light spot and the time interval β at which the light pulse is irradiated, whether the host vehicle 21 exists on a straight line satisfying A + B = 0 or the straight line Can be seen on the right or left side of In the above description, the case where the other vehicle 22 forms four light spots has been described. However, when the other vehicle 22 forms more light spots, the detection time interval Δt and the light pulse of each light spot can be obtained by the same method. The angle θ between the host vehicle 21 and the other vehicle 22 can be accurately obtained by obtaining the time lag with respect to the time interval β for irradiating the vehicle.

FIG. 21 shows the case where the other vehicle 22 forms the right-scanning light spots a1 to an and the left-scanning light spots b1 to bn, and sets the angle θ between the host vehicle 21 and the other vehicle 22 in the same manner as in FIG. It is the figure which showed the method of calculating | requiring. The own vehicle 21 calculates a deviation (A, B, C,...) Between detection time intervals of the respective light spots. Light spots ai and bj satisfying the following formula are obtained from the calculated shift in the detection time interval.
Lai−Lbj + Sai−Sbj = 0 Formula (21)
However, i = 1 to n and j = 1 to n. Sai (m) indicates the distance from the other vehicle 22 to the right-scanning light spot ai, and Lai (m) indicates the distance from the light spot ai to the host vehicle 21. Sbj (m) represents the distance from the other vehicle 22 to the light spot bj of the left scan, and Lbj (m) represents the distance from the light spot bj to the host vehicle 21. The host vehicle 21 determines the angle between the straight line connecting the light spot ai and the light spot bj and the straight line obtained by the above-described method (two straight lines according to the equation (20 ′)), and the light spot ai and the light spot. The arrangement of bj is known in advance. Whether the own vehicle 21 exists on the right side or the left side of the straight line connecting the light spots ai and bj, depending on the deviation of the detection time interval of the light spot included in each scan (the value of C in the above). I understand. Therefore, the angle θ between the host vehicle 21 and the other vehicle 22 can be obtained by obtaining the above ai and bj. Note that when there are no light spots ai and bj that satisfy Expression (21), that is, when the host vehicle 21 is not on the straight line of the arrow shown in FIG. 21, the left side of Expression (21) is closest to 0. And bj, the range of the angle θ between the host vehicle 21 and the other vehicle 22 can be determined.

  Next, a processing flow of the periphery monitoring device according to the present embodiment will be described with reference to FIG. FIG. 22 is a flowchart illustrating a process flow of the periphery monitoring device according to the third embodiment. The process shown in FIG. 22 is executed after the own vehicle 21 detects the light spot of the other vehicle 22 and the deviation (A, B, C,...) Of the detection time interval of each light spot is obtained. . In addition, in order to simplify description, in FIG. 22, it is assumed that the other vehicle 22 forms four light spots as shown in FIG.

  First, in step S101, it is determined whether or not the maximum value among the deviations A, B, and C of the detection time intervals of each light spot is smaller than a predetermined value x1. Here, the predetermined value x1 is a maximum value of a deviation of a predetermined detection time interval. As described above, the shift in the detection time interval varies depending on the size of the light projection pattern. When the deviation of the detection time interval is very large (when the determination result is No), it indicates that the size of the light projection pattern is very large and the distance between the other vehicle 22 and the projection position is very large. Therefore, since it is considered that the possibility that the own vehicle 21 and the other vehicle 22 collide with each other is low, the process proceeds to step S103 and the subsequent process ends. If the determination result is Yes, the process of step S102 is executed.

  In step S102, it is determined whether or not the maximum values of the detection time interval deviations A and C of the predetermined light spot are larger than a predetermined value x2. In this determination, it is determined whether or not the angle θ between the host vehicle 21 and the other vehicle 22 is in a very large range (the angle is close to 180 degrees) or very small (the angle is close to 0 degrees). . Here, the predetermined value x2 is a minimum value of a deviation of a predetermined detection time interval. When the deviation A of the detection time interval is very small (when the determination result is No), the host vehicle 21 exists at a position where the distances from the light spots a1 and a2 are substantially the same. That is, the host vehicle 21 is traveling in a state close to parallel with the other vehicle 22 (the angle is very small) or is traveling opposite the other vehicle 22 (the angle is very large). The same applies when the deviation C of the detection time interval is very small. Therefore, in this case, since it is considered that the own vehicle 21 and the other vehicle 22 are likely to pass each other, the process proceeds to step S104, and the subsequent process is terminated. If the determination result is Yes, the process of step S105 is executed. In the determination in step S102, the detection time interval deviation B is not a determination target for the following reason. That is, B indicates a shift in the detection time interval between the light spot a2 and the light spot b1. When this B is smaller than the predetermined value x2, the angle θ between the host vehicle 21 and the other vehicle 22 is close to a right angle and is not in the above range (the range where the angle is very large or small). When the angle θ is in the above range, B increases. Accordingly, when determining whether or not the angle range is as described above, the detection time interval deviation B between the light spots moving back and forth in the traveling direction when viewed from the other vehicle 22 is excluded. That is, in step S102, the detection time interval deviation of each light spot (a1 to an) of the right scan and the detection time interval deviation of each light spot (b1 to bn) of the left scan are determined as the objects of determination. For example, a shift in the detection time interval between the light spot an and the light spot b1 is not determined.

  In step S103, since the distance from the other vehicle 22 to the light projection pattern is long, it is determined that there is a low possibility that the host vehicle 21 and the other vehicle 22 will collide, and the process ends.

  In step S104, it is determined that the possibility of collision between the host vehicle 21 and the other vehicle 22 is low, and the process ends.

  In step S105, it is determined whether or not the detection time interval deviation C is greater than zero. Here, C indicates a shift in the detection time interval between the light spots b1 and b2. When C is larger than 0 (when the determination result is Yes), the other vehicle 22 is approaching from the left side of the host vehicle 21. When C is smaller than 0 (when the determination result is No), the other vehicle 22 is approaching from the right side of the host vehicle 21. If the determination result is Yes, the process of step S106 is performed. If the determination result is No, the process of step S108 is performed. In this determination, for example, a difference in detection time interval between the light spots a1 and a2 may be compared.

  In step S106, the angle θ between the host vehicle 21 and the other vehicle 22 is calculated based on the detection time interval deviations A, B, and C. The calculation method of the angle θ is as described above. When there are three or more light spots for the right scan and the left scan, the value of the angle θ or the range of the angle θ is calculated based on the difference in detection time interval between the light spots. In step S108, the same processing as in step S106 is performed, but the value of the angle θ is determined by the value of C (one of the two straight lines satisfying A + B = 0 shown in FIG. 18 is determined).

  In step S107, the size of the light projection pattern is obtained based on the detection time interval shift and the angle θ between the host vehicle 21 and the other vehicle 22, and the distance from the other vehicle 22 to the projection position of the light spot is obtained. . The method for obtaining the size of the light projection pattern from the difference in detection time interval is the method described in the first embodiment. Since the size of the light projection pattern obtained from the shift in the detection time interval varies depending on the angle between the host vehicle 21 and the other vehicle 22, it is corrected by the angle θ obtained in step S106. Then, the distance from the other vehicle 22 to the projection position is calculated based on the corrected size of the light projection pattern.

  In step S108, as in step S106, the angle θ between the host vehicle 21 and the other vehicle 22 is calculated based on the deviations A, B, and C of the detection time interval.

  In step S109, as in step S107, the distance from the other vehicle 22 to the projection position of the light spot is determined based on the shift in the detection time interval and the angle θ between the host vehicle 21 and the other vehicle 22.

  As described above, the distance from the obtained other vehicle 22 to the projection position of the light spot and the angle θ between the host vehicle 21 and the other vehicle 22 can be obtained. The periphery monitoring device can determine the possibility of collision between the host vehicle 21 and the other vehicle 22 based on the obtained distance and angle.

  In the present embodiment, the distance from the other vehicle 22 to the projection position of the light spot is made to correspond to the size of the light projection pattern, but the arrival time until the other vehicle 22 reaches the projection position can be made to correspond. Good. Then, the possibility of collision between the host vehicle 21 and the other vehicle 22 may be determined by obtaining the arrival time of the other vehicle 22.

  Further, the other vehicle 22 does not correspond the distance to the projection position of the light spot to the size of the light projection pattern, and forms a light projection pattern of a certain size on the road surface at a predetermined distance from the other vehicle 22. May be. In this case, the host vehicle 21 measures the angle θ based on the shape of the light projection pattern viewed from the host vehicle 21. Then, it may be determined that there is no collision when the angle θ is in the above range (the range where the angle is very large or small). Further, when the light projection pattern is formed at a position farther than the predetermined position from the other vehicle 22 by the pitch movement of the other vehicle 22, the size of the light projection pattern is projected at the position of the predetermined distance. Larger than the case. Therefore, when the size of the detected light projection pattern is larger than the predetermined size (determination in step S101 in FIG. 22), the host vehicle 21 determines that no collision occurs because the other vehicle 22 exists at a far position. May be. On the other hand, when the angle θ is in the above range and the size of the light projection pattern is smaller than the predetermined size, the distance between the host vehicle 21 and the other vehicle 22 is close, and there is a possibility of encounter collision. The host vehicle 21 may be determined to collide.

  Further, in the present embodiment, the angle θ is obtained from the deviation of the detection time interval of the light spot. However, in other embodiments, the angle θ can be obtained from the shape of the light projection pattern seen from the host vehicle 21. good. For example, the light receiving element 13 is replaced with a light receiving element having spatial resolution. Based on the position of each light spot in the light receiving element and the timing at which each light spot is received, the positional relationship of each light spot is determined. Then, it can be seen from which direction the vehicle 21 has detected the light spot from the obtained positional relationship.

  Moreover, the linear pattern may be sufficient as the pattern of the light which the other vehicle 22 forms on a road surface like 1st Embodiment. Further, the projection area may be formed by irradiating light on the entire projection area instead of the spot-like light spot. The pattern may be formed by an optical blank area.

  As described above, in the present invention, the position of another vehicle can be accurately measured by a simple method, and can be used as, for example, a periphery monitoring device mounted on a vehicle.

The block diagram which shows the structure of the periphery monitoring apparatus which concerns on 1st Embodiment. The figure which showed a mode that the irradiation means irradiated the light pulse by making the distance from the own vehicle to the projection position of the light spot correspond to the size of the light projection pattern The figure which showed the projection position of the light spot formed on a road surface when the own vehicle carries out pitch movement to the up-and-down direction with respect to the advancing direction by running on an uneven road surface. The figure which showed a mode that the own vehicle formed several sets of light spots in the predetermined position of the advancing direction The figure which showed a mode that the own vehicle calculated | required the distance from the other vehicle to the projection position of a light spot by detecting the light spot which the other vehicle formed in the detection area | region R. View of scan actuator 19 viewed from the side AA line end view of the scan actuator 19 cut along a plane parallel to the lower surface The figure explaining the pattern of the light spot formed when a polygon mirror is rotated The figure which showed a mode that several light pulses of the right scan which the other vehicle irradiated reflected on the detection area | region of the own vehicle, and were detected by the own vehicle The figure which showed typically the delay of time after three light pulses of right scan were emitted, and being detected by the own vehicle The figure which showed a mode that a plurality of light pulses of the left scan which other vehicles irradiated reflected in the detection field of the own vehicle, and are detected by the own vehicle The figure which showed typically the delay in time after three light pulses of a left scan were emitted and detected by the own vehicle. The figure which showed the relationship between the detection time interval and detection time of the light spot in 1st Embodiment Diagram showing how to find the light spot detection time The figure which showed the pattern of the light spot which the irradiation means in 2nd Embodiment forms A diagram showing how the other vehicle forms a right-scanning light spot and a left-scanning light spot on the circumference, and the vehicle detects the light spot. The figure which showed the relationship between the detection time interval and detection time of the light spot in 2nd Embodiment The figure which showed the pattern of the light spot which the irradiation means in 3rd Embodiment forms The figure which showed a mode that the own vehicle detected the light spot which the other vehicle formed when the own vehicle and the other vehicle are drive | working with a certain angle (theta). The figure which showed typically the delay in time after each light pulse is emitted from other vehicles until it detects with the own vehicle. A diagram showing a point (x, y) satisfying A + B = 0 The figure which showed the method of calculating | requiring angle (theta) of the own vehicle and other vehicles by the method similar to FIG. 18 when another vehicle forms the light spots a1-an of right scan, and the light spots b1-bn of left scan. The flowchart which shows the flow of a process of the periphery monitoring apparatus which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Perimeter monitoring apparatus 2 Detection means 3 Measurement means 4 Irradiation means 5 Collision judgment means 11 Lens 12 Filter 13 Light receiving element 16 Beam generator 17 Beam shaping lens 18 Polarization shaper 19 Scan actuator 21 Own vehicle 22 Other vehicles 61 Polygon mirror 62 Reflection mirror

Claims (20)

A surrounding monitoring device that measures the position of another vehicle by detecting a light projection pattern formed on the road surface by irradiating light from the other vehicle,
A predetermined region on the road surface in the traveling direction of the host vehicle is set as a detection region, and the positional relationship between the projection position where the light projection pattern is formed by the other vehicle and the position of the other vehicle is set in the detection region. Detecting means for detecting the light projection pattern formed corresponding to the size;
A periphery monitoring device comprising: a measuring unit that measures a positional relationship between the projection position and the other vehicle based on the size of the light projection pattern detected by the detecting unit. The other vehicle associates a distance from the other vehicle to the projection position as a positional relationship between the projection position and the other vehicle according to a size of the light projection pattern, and a distance from the other vehicle to the projection position. Irradiating a light beam so that a ratio with the size of the light projection pattern is constant,
2. The periphery monitoring according to claim 1, wherein the measurement unit measures the size of the light projection pattern and calculates a distance from the other vehicle to the projection position based on the measurement result. apparatus. The other vehicle associates an arrival time until the other vehicle reaches the projection position as a positional relationship between the projection position and the other vehicle according to a size of the light projection pattern, and the arrival time and the light projection. Irradiate the light beam so that the ratio to the pattern size is constant,
The periphery monitoring device according to claim 1, wherein the measurement unit measures the size of the light projection pattern and calculates the arrival time based on the measurement result.   4. The light projection pattern according to claim 1, wherein the light projection pattern is a plurality of light spots formed on a road surface by irradiating a plurality of light pulses at predetermined time intervals. 5. Perimeter monitoring device.   The periphery monitoring device according to claim 4, wherein the measurement unit calculates the size of the light projection pattern based on detection time intervals of the plurality of light spots detected by the detection unit. The other vehicle forms a light spot of a first pattern row and a second pattern row arranged on the road surface by irradiating a plurality of light pulses at predetermined time intervals as the light spot,
The measurement unit is configured to detect a difference between a detection time interval of the plurality of light spots included in the first pattern row detected by the detection unit and a detection time interval of the plurality of light spots included in the second pattern row. Based on the size of the light projection pattern,
The second pattern row is formed at a position different from the first pattern row in a direction different from the first pattern row at a position different from the first pattern row at a position different from the first pattern row. The perimeter monitoring device according to claim 4, wherein:   The first pattern row is formed on a circumference of a part of a predetermined ellipse, and the second pattern row is formed at a position different from the first pattern row on the circumference of the ellipse. The perimeter monitoring device according to claim 6, wherein:   The measurement unit measures an angle between the host vehicle and the other vehicle based on a detection time interval of a light spot included in the first pattern row and the second pattern row detected by the detection unit. The perimeter monitoring device according to claim 6, wherein:   The periphery according to any one of claims 1 to 8, further comprising collision determination means for determining a collision between the host vehicle and the other vehicle based on measurement information by the measurement means. Monitoring device. A surrounding monitoring device that measures the position of another vehicle by detecting a light projection pattern formed on the road surface by irradiating light from the other vehicle,
Detection means for detecting a light projection pattern formed in a predetermined region on the road surface by another vehicle in the detection region, with a predetermined region on the road surface in the traveling direction of the host vehicle as a detection region;
A periphery monitoring device comprising: a measuring unit that measures an angle of the traveling direction of another vehicle with respect to the traveling direction of the own vehicle based on the light projection pattern viewed from the own vehicle detected by the detecting unit. The other vehicle forms a plurality of light spots in a predetermined arrangement on the road surface by irradiating a plurality of light pulses at predetermined time intervals as the light projection pattern,
The periphery monitoring device according to claim 10, wherein the measurement unit measures the angle based on an arrangement of the plurality of light spots detected by the detection unit as viewed from the host vehicle.   The periphery monitoring device according to claim 11, wherein the measurement unit calculates the angle based on detection time intervals of the plurality of light spots detected by the detection unit. The other vehicle forms a light spot of a first pattern row and a second pattern row arranged on a road surface by irradiating a plurality of light pulses at predetermined time intervals as the light projection pattern,
The measurement means is based on detection time intervals of a plurality of light spots included in the first pattern row detected by the detection means and detection time intervals of a plurality of light spots included in the second pattern row. Calculating the angle,
The second pattern row is formed at a position different from the first pattern row in a direction different from the first pattern row at a position different from the first pattern row at a position different from the first pattern row. The perimeter monitoring device according to claim 10, wherein   The first pattern row is formed substantially perpendicular to the traveling direction of the other vehicle, and the second pattern row has a direction of a trajectory connecting a plurality of light spots in the irradiation order as the first pattern row. 14. The perimeter monitoring device according to claim 6 or 13, wherein the perimeter is formed in a reverse direction.   The periphery according to any one of claims 10 to 14, further comprising a collision determination unit configured to determine a collision between the host vehicle and the other vehicle based on measurement information obtained by the measurement unit. Monitoring device.   The periphery monitoring device according to claim 9, wherein the collision determination unit determines that no collision occurs when the size of the light projection pattern detected by the detection unit is equal to or larger than a predetermined size. Based on measurement information by the measurement means, further comprising a collision determination means for determining a collision between the host vehicle and the other vehicle;
The collision determination unit determines that no collision occurs when a deviation between a detection time interval of the plurality of light spots detected by the detection unit and the predetermined time interval is not within a predetermined range. Item 12. The periphery monitoring device according to Item 5 or 11.   The said other vehicle makes the said light projection pattern formed in the said projection position 1 set, and forms several sets of light projection patterns in the position where the distance from this other vehicle mutually differs. Or the periphery monitoring apparatus of 10. A surrounding monitoring device that measures the position of another vehicle by irradiating the other vehicle with light,
A plurality of light blank projection patterns in which a predetermined area on the road surface in the traveling direction of the host vehicle is set as a detection area and the detection light is not irradiated with the light formed on the road surface by the other vehicle shielding a part of the light. Detecting means for detecting
Measuring means for measuring the positional relationship between the projection position and the other vehicle based on the size of the light blank projection pattern detected by the detection means;
The said other vehicle forms the said optical blank projection pattern by making the positional relationship of the said projection position and the position of the said other vehicle respond | correspond to the magnitude | size of the said optical blank projection pattern, The periphery monitoring apparatus characterized by the above-mentioned.   The peripheral monitoring device according to claim 19, wherein the light blank projection pattern is a plurality of light blank spots formed on a road surface by shielding a part of light.

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