JP6477340B2 - Road boundary detection device, self-position estimation device, and road boundary detection method - Google Patents

Description

  The present invention relates to a road boundary detection device, a self-position estimation device, and a road boundary detection method.

  A roadside object detection device that detects road surface height information from a camera image and detects a road surface level difference caused by a roadside object such as a curb from this height information is known (see Patent Document 1).

JP 2014-002608 A

  The roadside object detection device described above recognizes a step when the amount of change in the height of the road surface is equal to or greater than a threshold value. Therefore, when a slope is provided instead of a curb at a place where the vehicle can enter the site from the roadway, a step difference beyond the slope is erroneously detected, and the road boundary cannot be detected correctly. Sometimes.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a road boundary detection device, a self-position estimation device, and a road boundary detection method that improve the detection accuracy of the road boundary.

  A road boundary detection apparatus according to an aspect of the present invention includes a distance measuring unit that detects the height of a road surface around a vehicle. The road boundary detection device detects a step based on the height of the road surface, and if no step is detected in a predetermined range in the vehicle width direction of the road surface, the road boundary detection device detects the slope based on the gradient of the road surface in the vehicle width direction. The boundary with the roadway is detected, and the boundary or step between the slope and the roadway is estimated as the road boundary.

  According to one embodiment of the present invention, a boundary between a slope and a roadway can be detected as a road boundary at a place where a slope is provided instead of a step. Therefore, the road boundary detection accuracy is improved.

FIG. 1 is a block diagram showing an overall configuration of a road boundary detection device 1 according to the first embodiment. FIG. 2 is a perspective view showing an example of a linear step determination position (Pa) set on the road surface around the vehicle (Vc). FIG. 3 is an overhead view corresponding to FIG. FIG. 4 is a graph showing the height distribution of the road surface (Froad) at the step determination position (Pa), and shows a case where there is a step (LD). FIG. 5 is a graph showing the height distribution of the road surface (Froad) at the step determination position (Pa), and shows a case where there is a slope instead of the step (LD). FIG. 6 is a top view illustrating an example of a road boundary detection region (Hg). FIG. 7 is a top view showing another example of the road boundary detection region (Hg ′). FIG. 8 is a flowchart showing an example of a road boundary detection method using the road boundary detection device 1 of FIG. FIG. 9 is a flowchart illustrating an example of a detailed procedure of step S13 in FIG. FIG. 10 is a flowchart showing another example of the detailed procedure of step S13 of FIG. FIG. 11 is a perspective view showing an example of the step determination position (Pa) when a stereo camera is installed on the side of the vehicle (Vc). FIG. 12 is a bird's-eye view showing an example of a 360-degree LRF in which the LRF (12) is set at the center of the roof of the vehicle (Vc) and the entire area around the vehicle is an irradiation range. FIG. 13 is a flowchart showing an example of a road boundary detection method when a laser range finder (LRF) is used as the distance measuring sensor 12. FIG. 14 is a block diagram showing the overall configuration of the self-position estimation apparatus 2 according to the second embodiment.

(First embodiment)
Next, embodiments of the present invention will be described in detail with reference to the drawings.

  With reference to FIG. 1, the whole structure of the road boundary detection apparatus 1 concerning 1st Embodiment is demonstrated. The road boundary detection device 1 detects the height of a road surface (hereinafter referred to as “road surface”) around the vehicle, and detects a step on the road surface based on a change in the height of the road surface. If no step is detected in a predetermined range in the vehicle width direction on the road surface, the road boundary detection device 1 determines that there is a possibility that a slope is provided instead of the step. Then, the boundary between the slope and the roadway is detected based on the gradient of the road surface in the vehicle width direction. As described above, the road boundary detection device 1 attempts to detect a step in a predetermined range, and when it is not detected, detects the road boundary with high accuracy by detecting the boundary between the slope and the roadway.

  Specifically, the road boundary detection device 1 includes a distance measurement sensor 12 that detects the height of a road surface around the vehicle, and a microcomputer that executes a series of information processing for detecting a road boundary from measurement data obtained by the distance measurement sensor 12. 13.

  An example of the distance measuring sensor 12 can record information on the depth direction (distance from the sensor 12) of the object around the vehicle by simultaneously photographing the object around the vehicle from a plurality of different directions. It is a stereo camera. By performing predetermined image processing on the stereo image obtained by the stereo camera, it is possible to acquire three-dimensional information about the object image shown in the stereo image of the object around the vehicle. Objects around the vehicle include roads and curbs. Details will be described later.

  The microcomputer 13 includes, for example, a general-purpose microcontroller including a CPU, a memory, and an input / output unit, and configures a plurality of information processing circuits included in the road boundary detection device 1 by executing a computer program installed in advance. To do. The microcomputer 13 repeatedly executes a series of information processing cycles for detecting a road boundary from measurement data obtained by the distance measuring sensor 12 at predetermined time intervals. The microcomputer 13 may also be used as an electronic control unit (ECU) used for other control related to the vehicle.

  The plurality of information processing circuits configured by the microcomputer 13 include an arithmetic circuit 14, a step determination position circuit 15, a step detection circuit 18, a slope boundary detection circuit 19, and a road boundary estimation circuit 20.

  The arithmetic circuit 14 constitutes a distance measuring unit 11 together with the distance measuring sensor 12 and acquires a series of stereo images for acquiring three-dimensional information on the image of the object shown in the stereo image of the object around the vehicle from the stereo image obtained by the stereo camera. Perform the process.

  For example, the arithmetic circuit 14 performs lens distortion correction processing that corrects lens distortion on a stereo image, and performs parallelization correction processing (parallel equivalence processing) that corrects the vertical position between the stereo images. Then, a stereo matching process for estimating the correspondence of each pixel between stereo images is performed. Thereby, not only the two-dimensional coordinates of the object on the imaging surface of the stereo camera but also the distance from the imaging surface of the stereo camera to the object can be calculated. Therefore, the distance and direction to the object around the vehicle can be detected.

  The arithmetic circuit 14 can acquire three-dimensional information of an object around the vehicle on the coordinates of the distance measurement data by further performing a coordinate conversion process. The three-dimensional information of the object around the vehicle includes three-dimensional information of the road surface around the vehicle. Therefore, the arithmetic circuit 14 can acquire the height of the road surface around the vehicle.

  In the lens distortion correction process, for example, a flat plate representing a black and white checkered pattern is photographed by each camera, and the lens distortion parameter and the camera lens center parameter are set so that the checkered grid points are formed in a rectangular grid. presume. However, this processing may be a general method for correcting lens distortion, and is not particularly limited in the present embodiment.

  Parallelization correction processing is performed by taking a flat plate representing a black and white checkered pattern with both cameras of the stereo camera, for example, so that the positions of the checkered lattice points are the same vertical position on each camera image. The spatial position parameter and the angle parameter are estimated. However, this process may be a general technique for performing the parallelization correction process, and is not particularly limited in the present embodiment.

  In the stereo matching process, for example, each pixel of the left camera image is associated with which pixel of the right camera image with reference to the left camera image. For example, the absolute value of the luminance value of each pixel of the left camera image and the luminance value of each pixel of the right camera image is calculated as an evaluation value, and the pixel of the right camera image having the smallest evaluation value is associated with the pixel. calculate. The evaluation value calculation method includes, for example, a method using a sum of absolute difference values (SAD: Sum of Absolute Differences) or a sum of squared difference values (SSD: Sum of Squared Differences), and a range of evaluation value calculation for each pixel. There is a method including peripheral pixels of each pixel instead of one point. The calculation method of the evaluation value may be another general method and is not particularly limited in the present embodiment.

  The step determination position circuit 15 sets a linear step determination position in the vehicle width direction on the road surface around the vehicle on the coordinates of the distance measurement data detected by the distance measurement sensor 12. For example, as shown in FIG. 2 and FIG. 3, a step determination position (Pa) extending from the distance measuring sensor 12 by a predetermined distance in the first predetermined direction (Da) and extending in a direction orthogonal to the first predetermined direction (Da). ) Is set on the road surface on the coordinates of the distance measurement data. 2 and 3 show an example in which the distance measuring sensor 12 is installed at the front of the vehicle (Vc) and the traveling direction of the vehicle (Vc) is the first predetermined direction (Da). Therefore, the step determination position (Pa) extending in the vehicle width direction is set in front of the vehicle (Vc) on the coordinates of the distance measurement data. The step determination position (Pa) is set within the imaging range of the stereo camera. The first predetermined direction (Da) is not limited to the traveling direction of the vehicle (Vc).

  In the example shown in FIGS. 2 and 3, a step (LD) in which the height of the road surface changes discontinuously is formed on the shoulder of the road in the vehicle width direction of the roadway on which the vehicle (Vc) can travel. ing. A step portion (for example, a sidewalk or a road shoulder) that is one step higher than the roadway is provided outside the roadway with the step (LD) as a boundary. As described above, in the example shown in FIGS. 2 and 3, the road is composed of a roadway and a stepped portion (sidewalk or shoulder), and a step (LD) is formed at the boundary between the roadway and the stepped portion (sidewalk or shoulder). ing. The linear step determination position (Pa) extends in a direction crossing the roadway, the step (LD), and the step portion (sidewalk).

  The positional relationship of the step determination position (Pa) with respect to the distance measuring sensor 12 is merely an example. Another example will be described later with reference to FIGS. 11 and 12.

  The step determination position circuit 15 calculates the height data distribution (distance measurement data) of the measurement points on the road surface at the step determination position (Pa) from the road surface height acquired by the arithmetic circuit 14. The vertical axis in FIG. 4 indicates the height of the road surface (Froad), and the horizontal axis indicates the step determination position (Pa) extending in the vehicle width direction.

  As shown in FIG. 4, a step (LD) is formed at the boundary between the roadway (Rr) and the step portion (Rd). The road surface (Froad) of the roadway (Rr) is provided with a slope (cant) whose height decreases from the center toward the road shoulder at both ends. This is a general road design and structure that improves the drainage of the roadway and does not collect water on the roadway. In the level difference (LD), the road surface (Froad) increases rapidly, and the road surface (Froad) of the level difference portion (Rd) forms a flat surface that is one step higher than the roadway (Rr). For example, a sidewalk is provided.

  The level difference detection circuit 18 detects a level difference (LD) on the road surface based on the height change of the road surface (Froad) at the level difference determination position (Pa). The step detection circuit 18 can determine a change in the height of the road surface (Froad) using the road surface height distribution (ranging data) at the step determination position (Pa) shown in FIG.

  An example of a method for detecting a level difference (LD) will be described. A travelable area is set on the step determination position (Pa), and the slope of the road surface (Froad) is approximated by a curve in the travelable area. The travelable region is a region where the vehicle (Vc) can travel and indicates a boundary of the roadway, for example, a region not including a step. Then, a road boundary detection area (Hg) adjacent to the travelable area is set at the step determination position (Pa). The approximate curve is compared with the height of the road surface (Froad) in the road boundary detection region (Hg). It is determined that there is a step at a location where the difference between the approximate curve and the road surface (Froad) is 0.1 m or more, which is a general curb height. The road boundary detection area (Hg) will be described later with reference to FIGS.

  A specific method for detecting the level difference (LD) is not limited to the above method. Any known method, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2014-002608 may be used.

  The step detection circuit 18 tries to detect a step in a predetermined range on the step determination position (Pa) in the vehicle width direction of the road surface (Froad). If no step is detected in the predetermined range, the detection of the step may be abandoned.

With reference to FIG.6 and FIG.7, the predetermined range on the level | step difference determination position (Pa) of the vehicle width direction of a road surface (Froad) is demonstrated. FIG. 6 is a top view showing a road boundary detection region (Hg) as an example of the predetermined range. The step detection circuit 18 first estimates a travelable region (G ₁ ) in the traveling direction of the vehicle (Vc) at the step determination position (Pa). The travelable region (G ₁ ) is a region in which the vehicle (Vc) can travel and indicates a boundary of the roadway, for example, a region that does not include a step. As shown in FIG. 6, the level difference detection circuit 18 uses a region in which a predetermined travel margin region is added to the width (Wvc) of the vehicle (Vc) as a travelable region (G ₁ ) in the traveling direction of the vehicle (Vc). ). For example, the travel margin area is set to 0.1 m to 0.5 m so as not to include an actual road boundary. Cvc represents a central axis in the vehicle width direction of the vehicle (Vc).

The road boundary detection region (Hg) is a region from the end of the travelable region (G ₁ ) to a predetermined distance in the vehicle width direction. For example, the predetermined distance may be set in an area including the road edge (B _ON ) within the effective detection distance (10 m) of the distance measuring sensor 12.

FIG. 7 is a top view showing a road boundary detection region (Hg ′) as another example of the predetermined range. The road boundary detection area (Hg ′) can also be set based on the step positions (P _B1 , P _B2 ,...) Detected in the past processing cycle. For example, the current road boundary detection region (Hg ′) may be a region extended from the previous step position (P _B1 ) by a certain margin distance (P _LA ) in the vehicle width direction. Of course, the starting point of the road boundary detection area (Hg ′) is the end of the travelable area (G ₁ ). The definition of the travelable area (G ₁ ) is the same as in FIG.

  When no step is detected in a predetermined range on the step determination position (Pa) in the vehicle width direction on the road surface (Froad), the slope boundary detection circuit 19 determines the slope based on the gradient in the vehicle width direction on the road surface (Froad). Detect the boundary between the road and the roadway. A slope is formed at a place where the vehicle can enter the site from the roadway, as shown in FIG. 5, instead of the step (LD) in FIG. At the boundary between the slope and the roadway (Rr), a discontinuous road surface (Froad) gradient change is formed. For example, as shown in FIG. 5, the sign of the slope of the roadway (Rr) and the sign of the slope of the slope are different.

For example, the slope boundary detection circuit 19 scans the gradient in the vehicle width direction of the road surface (Froad) from both ends (D _BA , D _FR ) of the road boundary detection region (Hg), and from the position where the gradients intersect, The position of the boundary with the roadway can be detected. Specifically, first, the road boundary detection area (Hg) is divided into a plurality of sections (K _{d1 to} K _d7 ), and the gradient in the vehicle width direction of the road surface is detected for each section (K _{d1 to} K _d7 ). The gradient of each section (K _{d1 to} K _d7 ) is scanned from both ends (D _BA , D _FR ) of the road boundary detection region (Hg). The slope boundary detection circuit 19 can detect a section (K _d3 ) in which the gradient in the vehicle width direction of the road surface (Froad) changes more than the reference value as a boundary between the slope and the roadway. An example of the reference value is 10 degrees. Alternatively, as shown in FIG. 5, the slope boundary detection circuit 19 may detect a point where the sign of the gradient in the vehicle width direction of the road surface (Froad) is reversed as the boundary between the slope and the roadway.

  The road boundary estimation circuit 20 estimates the boundary or step (LD) between the slope and the roadway (Rr) as the road boundary. The road boundary estimation circuit 20 estimates the step (LD) as a road boundary if a step is detected in a predetermined range on the step determination position (Pa) in the vehicle width direction of the road surface (Froad). When the step is not detected and the boundary between the slope and the roadway is detected, the road boundary estimation circuit 20 estimates the boundary between the slope and the roadway as the road boundary.

  With reference to FIG. 8, an example of a road boundary detection method using the road boundary detection device 1 of FIG. 1 will be described.

  First, in step S01, a stereo image is acquired using a stereo camera which is an example of the distance measuring sensor 12. In step S03, the arithmetic circuit 14 performs lens distortion correction processing for correcting lens distortion on the stereo image, and performs parallelization correction processing for correcting the vertical position between the stereo images. Proceeding to step S05, the arithmetic circuit 14 performs a stereo matching process for estimating the correspondence of each pixel between stereo images. Thereby, the distance and direction to the object around the vehicle can be detected. Furthermore, the arithmetic circuit 14 can acquire the three-dimensional information of the road surface around the vehicle on the coordinates of the distance measurement data by performing the coordinate conversion process.

  Proceeding to step S07, the step determining position circuit 15 is arranged in a vehicle width direction on the road surface around the vehicle on the coordinates of the distance measurement data detected by the distance measurement sensor 12, as shown in FIGS. The step determination position (Pa) is set. Then, the step determination position circuit 15 calculates the road surface height distribution (ranging data) at the step determination position (Pa) from the three-dimensional road surface information acquired by the arithmetic circuit 14, as shown in FIG. .

  Proceeding to step S09, as shown in FIG. 6 or FIG. 7, the level difference detection circuit 18 in the road boundary detection region (Hg, Hg ′) on the level difference determination position (Pa) in the vehicle width direction of the road surface (Froad). Attempts to detect the step (LD). If a step (LD) is detected (YES in step S11), the process proceeds to step S15 without performing step S13. If a step (LD) is not detected (NO in step S11), the process proceeds to step S13. .

  In step S13, the slope boundary detection circuit 19 detects the boundary between the slope and the roadway based on the gradient of the road surface (Froad) in the vehicle width direction. In step S15, the road boundary estimation circuit 20 estimates the boundary or step (LD) between the slope and the roadway U (Rr) as the road boundary. If a step (LD) is detected (YES in step S11), the step (LD) is estimated as a road boundary. On the other hand, when the boundary between the slope and the roadway is detected in step S13, the boundary between the slope and the roadway is estimated as the road boundary.

  With reference to FIG. 9, an example of the detailed procedure of step S13 of FIG. 8 performed by the slope boundary detection circuit 19 will be described.

First, the road boundary detection region (Hg) in the vehicle width direction of the road surface (Froad) is divided into a plurality of sections (K _{d1 to} K _d7 ) (S301). In step S303, the gradient of the road surface is calculated for each section (K _{d1 to} K _d7 ). In step S305, the gradient of each section (K _{d1 to} K _d7 ) is scanned from both ends (D _BA , D _FR ) of the road boundary detection region (Hg) in the vehicle width direction of the road surface (Froad). In step S307, it is determined whether or not there is a portion where the sign of the gradient in the vehicle width direction of the road surface (Froad) is reversed. If there is a part to be reversed (YES in S307), the part is detected as a boundary between the slope and the roadway (S309). If there is no portion to be reversed (NO in S307), the detection of the boundary between the slope and the roadway is abandoned (S311). As described above, the slope boundary detection circuit 19 can detect the position of the boundary between the slope and the roadway from the sign change of the gradient.

  With reference to FIG. 10, another example of the detailed procedure of step S13 in FIG. 8 will be described. Compared to FIG. 9, S301, S303, S309, and S311 are the same, but S308 is performed instead of S307, and S305 of FIG. 9 is not performed.

In step S308, the slope boundary detection circuit 19 scans the gradient of each section (K _{d1 to} K _d7 ) from one end (D _BA , D _FR ) of the road boundary detection region (Hg). Then, it is determined whether or not there is a section in which the gradient in the vehicle width direction of the road surface (Froad) changes more than a reference value (for example, 10 degrees). If there is a section that changes more than the reference value, the process proceeds to step S309, and if there is no section that changes more than the reference value, the process proceeds to step S311.

  The road boundary detection apparatus 1 continuously detects a road boundary by repeatedly performing a series of processing cycles shown in FIG. 8 at a predetermined period. The detected position of the road boundary is a relative position based on the vehicle (Vc). The detected road boundary information is associated with vehicle behavior information from the previous detection time to the current detection time and stored in the memory. Therefore, the road boundary detection apparatus 1 can obtain the trajectory of the road boundary that is repeatedly detected by calculating the moving distance and moving direction of the vehicle from the behavior information of the vehicle. The vehicle behavior information can be obtained from a known method. For example, visual odometry information by a stereo camera, a combination of vehicle speed information and vehicle yaw rate information, or self-position information by GPS (satellite positioning system) can be used.

  In the flowchart of FIG. 8, the slope boundary detection circuit 19 proceeds to step 13 when the step (LD) on the road surface is not detected in a certain section where the vehicle travels, and the boundary between the slope and the roadway is detected. It may be detected. In practice, there may be a processing cycle in which a step (LD) is not detected due to noise even when a vehicle is traveling on a road where a continuous step (LD) is formed without interruption. Alternatively, since only a part of the continuous level difference (LD) is broken, a processing cycle in which the level difference (LD) is not detected may be included.

  As described above, if Step S13 is easily executed due to noise or partial collapse of the level difference, a processing delay occurs, and the operation of the road boundary detection device 1 becomes unstable. Therefore, the level difference detection circuit 18 determines that no level difference has been detected only when the level difference (LD) on the road surface is not continuously detected in a certain section in which the vehicle travels (NO in step S11). Even if there is a processing cycle in which a step is not detected, it is not determined that a step has not been detected unless the cycle is repeated until the vehicle travels through a certain section (YES in step S11). Thereby, the efficient operation | movement of the road boundary detection apparatus 1 is implement | achieved. In addition, the case where the step is not detected in three consecutive cycles is exemplified as the certain section in which the vehicle travels.

  As described above, according to the first embodiment, the following operational effects can be obtained.

  When no step (LD) is detected in the road boundary detection region (Hg) in the vehicle width direction of the road surface (Froad), the boundary between the slope and the roadway is detected based on the gradient in the vehicle width direction of the road surface (Froad). Then, the boundary between the slope and the road is estimated as the road boundary. As a result, in the place where the slope is provided instead of the step (LD), the boundary between the slope and the roadway can be detected as the road boundary instead of the step beyond the slope. Therefore, the road boundary can be detected with high accuracy.

The slope boundary detection circuit 19 scans the gradients in the vehicle width direction of the road surface (Froad) from both ends (D _BA , D _FR ) of the road boundary detection region (Hg), and from the position where the gradients intersect, Detect the boundary position of. As a result, since the gradient in the vehicle width direction of the road surface (Froad) greatly changes at the position where the gradient in the vehicle width direction of the road surface (Froad) intersects, the position of the boundary between the slope and the roadway is accurately determined from this intersection position. It can be detected well.

  The level difference detection circuit 18 repeatedly detects the position of the level difference (LD) on the road surface. The slope boundary detection circuit 19 sets a road boundary detection region (Hg) based on the position of the step (LD) on the road surface detected last time. Thereby, since the area | region where a road boundary is detected can be narrowed down beforehand, the time required for the detection of a road boundary can be shortened and calculation load can be reduced.

  The slope boundary detection circuit 19 detects the boundary between the slope and the roadway when a step (LD) on the road surface is not detected in a certain section where the vehicle travels (S13). For example, even if a step is not detected only in a short section that does not reach a certain section due to noise or partial collapse of the step, the slope boundary detection process (S13) is not started. Frequent occurrence of the slope boundary detection process flow is suppressed, and the stability of the system is improved.

  In the road boundary detection area (Hg), the slope boundary detection circuit 19 detects a point where the gradient in the vehicle width direction of the road surface changes more than the reference value as a boundary between the slope and the roadway. Thereby, since the reference value can be set in consideration of the inclination angle of the general slope and the inclination angle of the roadway, the boundary between the slope and the roadway can be detected with high accuracy.

  The slope boundary detection circuit 19 detects, as a boundary between the slope and the roadway, a portion where the sign of the gradient in the vehicle width direction of the road surface is reversed in the road boundary detection region (Hg). Since the slope of the general slope and the slope of the roadway are opposite, the boundary between the slope and the roadway can be detected with high accuracy.

(First modification)
As shown in FIG. 11, the stereo camera as the distance measuring sensor 12 is installed not on the front part of the vehicle (Vc) but on the side part of the vehicle (Vc), and the imaging range of the stereo camera is set on the vehicle (Vc) side. It doesn't matter as you go. Also in this case, the traveling direction of the vehicle (Vc) is the first predetermined direction (Da). Thereby, the level | step difference determination position circuit 15 can set the linear level | step difference determination position (Pa) which cross | intersects a level | step difference (LD) on the road surface of the circumference | surroundings (side) of a vehicle. Specifically, a step determination position (Pa) extending from the distance measuring sensor 12 by a predetermined distance in the first predetermined direction (Da) and extending in a direction orthogonal to the first predetermined direction (Da) can be set. .

(Second modification)
Another example of the distance measuring sensor 12 is a laser range finder (LRF). The LRF irradiates a laser toward an object around the vehicle, and observes the laser reflected and returned to the object. The LRF measures the azimuth in which the object is located based on the laser irradiation direction, and measures the distance to the object based on the time from the laser irradiation to the observation of the reflected laser. LRF is also called a laser scanner. The LRF irradiation range can be arbitrarily set. FIG. 12 shows an example of a 360 degree LRF in which the LRF (12) is set at the center of the roof of the vehicle (Vc) and the entire periphery is in the irradiation range. The step determination position circuit 15 sets a step determination position (Pa) that is separated from the distance measuring sensor 12 by a predetermined distance in the first predetermined direction (Da) and extends in a direction orthogonal to the first predetermined direction (Da). Accordingly, the traveling direction of the vehicle (Vc) is set to the first predetermined direction (Da) in the same manner as the example of FIG. 2 in which the distance measuring sensor 12 is installed at the front portion of the vehicle (Vc). The extending step determination position (Pa) is set in front of the vehicle (Vc).

  In addition, it becomes possible to investigate the vehicle traveling direction over a wide range during traveling by mounting the LRF with a depression angle. It is also possible to use a multi-layer LRF capable of simultaneously irradiating a plurality of lasers.

  The step detection method when a laser range finder (LRF) is used as the distance measuring sensor 12 is different in that steps S21 and S23 shown in FIG. 13 are performed instead of S01 to S05 in FIG. Other steps S07 to S13 are the same as those in FIG.

  In step S21, the LRF (12) measures the distance to the object together with the direction of the object irradiated with the laser. The measurement data is transmitted to the arithmetic circuit 14. Proceeding to step S23, the arithmetic circuit 14 converts the measurement data in the polar coordinate system with the LRF (12) as the origin into an orthogonal coordinate system with the vehicle (Vc) as the origin. Thereby, the arithmetic circuit 14 can acquire the three-dimensional information of the road surface around the vehicle. Thereafter, the process proceeds to step S07.

(Second Embodiment)
With reference to FIG. 14, the whole structure of the self-position estimation apparatus 2 concerning 2nd Embodiment is demonstrated. The self-position estimation device 2 collates the road boundary detected by the road boundary detection device 1 of the first embodiment with information indicating the road boundary included in the map information, so that the vehicle position (Vc) is displayed on the map. Estimate the position.

  Specifically, the self-position estimation device 2 includes a distance measurement sensor 12, a microcomputer 13 that executes a series of information processing for estimating the self-position from measurement data obtained by the distance measurement sensor 12, and a map that includes information indicating a road boundary. And a map database 23 for storing information. In addition to the information processing circuit (14, 15, 18, 19, 20) shown in FIG. 1, the microcomputer 13 executes a computer program that is installed in advance, in addition to a map information acquisition circuit 21 and a self-position estimation circuit. 22 is further configured.

  The map information acquisition circuit 21 acquires map information around the vehicle from the map database 23. The self-position estimation circuit 22 estimates the position of the vehicle (Vc) on the map by comparing information indicating the road boundary included in the map information with the road boundary estimated by the road boundary estimation circuit 20.

  The road boundary estimation circuit 20 detects that a step (LD) is detected outside the predetermined range on the step determination position (Pa) in the vehicle width direction on the road surface, and if the boundary between the slope and the road is not detected, the road boundary estimation circuit 20 The step detected in step 1 is not included in the estimation of the road boundary.

  Specifically, the level difference detection circuit 18 cannot detect the level difference (LD) in the road boundary detection area (Hg, Hg ′) shown in FIG. 6 or FIG. 7, and the road boundary detection area (Hg, Hg ′). A step (LD) was detected outside. The slope boundary detection circuit 19 did not detect the boundary between the slope and the roadway. In this case, the road boundary estimation circuit 20 does not estimate the step (LD) outside the road boundary detection area (Hg, Hg ′) as a road boundary. As a result, it is possible to prevent the step difference beyond the slope from being erroneously estimated as the road boundary, and the detection accuracy of the road boundary is improved.

  Although the embodiments of the present invention have been described as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

DESCRIPTION OF SYMBOLS 1 Road boundary detection apparatus 2 Self-position estimation apparatus 11 Distance measuring part 12 Distance sensor 13 Microcomputer 14 Calculation circuit 15 Level | step difference determination position circuit 18 Level | step difference detection circuit 19 Slope boundary detection circuit 20 Road boundary estimation circuit 21 Map information acquisition circuit 22 Self Position estimation circuit 23 Map database G ₁ Travelable area Froad Road surface Hg Road boundary detection area (predetermined range)
Pa Step judgment position LD Step Vc Vehicle

Claims (8)

A distance measuring unit for detecting the height of the road surface around the vehicle;
A step detecting circuit for detecting a step on the road surface based on a change in the height of the road surface;
A slope boundary detection circuit for detecting a boundary between a slope and a roadway based on a gradient in the vehicle width direction of the road surface when the step is not detected in a predetermined range in the vehicle width direction of the road surface;
A road boundary estimation circuit for estimating a boundary between the slope and the roadway or the step as a road boundary;
A road boundary detection apparatus comprising:   The slope boundary detection circuit scans a gradient in the vehicle width direction of the road surface from both ends of the predetermined range, and detects the position of the boundary between the slope and the roadway from the position where the gradient intersects. The road boundary detection device according to claim 1. The step detection circuit repeatedly detects the position of the step on the road surface,
The road boundary detection device according to claim 1, wherein the slope boundary detection circuit sets the predetermined range based on a position of a step on the road surface detected last time.   4. The slope boundary detection circuit according to claim 1, wherein the slope boundary detection circuit detects a boundary between the slope and a roadway when a step on the road surface is not detected in a certain section in which the vehicle travels. The road boundary detection device according to any one of the above.   The slope boundary detection circuit detects, as the boundary between the slope and the roadway, a portion where a gradient in the vehicle width direction of the road surface changes more than a reference value in the predetermined range. 5. The road boundary detection device according to any one of 4 above.   5. The slope detection circuit according to claim 1, wherein the slope boundary detection circuit detects, as the boundary between the slope and the roadway, a portion where a sign of a gradient in the vehicle width direction of the road surface is reversed in the predetermined range. The road boundary detection device according to claim 1. The road boundary detection device according to any one of claims 1 to 6,
A map information acquisition circuit for acquiring map information around the vehicle;
A self-position estimation circuit that estimates the position of the vehicle on the map by comparing information indicating the road boundary included in the map information with the road boundary estimated by the road boundary estimation circuit; Prepared,
The road boundary estimation circuit detects the step detected outside the predetermined range when the step is detected outside the predetermined range in the vehicle width direction of the road surface and the boundary between the slope and the roadway is not detected. Is not included in the estimation of the road boundary. Detect the road surface height around the vehicle,
Based on the change in the height of the road surface, a step on the road surface is detected,
When the step is not detected in a predetermined range in the vehicle width direction of the road surface, based on the gradient of the road surface in the vehicle width direction, the boundary between the slope and the roadway is detected,
A road boundary detection method, wherein a boundary between the slope and a roadway or the step is estimated as a road boundary.

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