JP6932167B2 - Road characterization device - Google Patents

Description

The present invention relates to a device for determining the characteristics of a road based on three-dimensional measurement data of a surface shape measured while traveling on a road or the like.

If the shape of the road can be specified by measurement and road shape data such as the road edge, the center of the road, and the center of the lane can be obtained, it can be used for automatic driving of automobiles, driving assistance control, and the like.

For example, Patent Document 1 discloses a method capable of accurately measuring the slope of a road. According to this method, it is possible to measure the inclination of the road depending on the location and continuously obtain the change of the inclination.

Further, Patent Document 2 discloses a system in which the speed and steering angle of an automobile are acquired by a sensor and the curvature of a road is estimated based on these data. Thereby, the curvature of the road can be estimated and used for avoiding a collision or the like.

Further, Patent Document 3 discloses a device that acquires movement on a road as three-dimensional locus data and connects a straight line and an arc at a curved portion of the road by a relaxation curve (clothoid curve).

Japanese Patent Application Laid-Open No. 11-100809 JP 2012-131496 JP-A-2014-160064

However, in the techniques of Patent Document 1 and Patent Document 2, although the slope of the road and the curvature of the road can be specified, the end of the road, which is the boundary with the sidewalk, can be specified, and the center of the road, the center of the lane, etc. can be specified. Could not be identified.

Further, in Patent Document 3, a road feature can be obtained more accurately by connecting a straight portion and a curved portion of a road with a clothoid curve. However, in Patent Document 3, the straight line portion and the arc portion are first determined, and then the clothoid curve is determined. However, it is difficult to clearly determine the start point / end point of the straight line portion and the start point / end point of the arc portion, and therefore there is a possibility of determining a clothoid curve having a large error.

Further, in each of the above patent documents, how to treat the road center line and the lane center line at the branch portion of the road is not examined, and even the problem is not recognized.

An object of the present invention is to solve at least one of the above problems and provide an accurate road characterization device.

Some independently applicable features of the present invention are shown below.

(1) (3) The road feature determining device according to the present invention is a road feature determining device that determines road features based on three-dimensional measurement data of surface points measured while traveling on a road. Cross-section setting means for setting cross sections perpendicular to the traveling direction at predetermined intervals, traveling point determining means for determining the intersection of the traveling line connecting the traveling loci and the cross-section as a traveling point, and the cross section. In, a straight line connecting a surface point at a position moved horizontally from the apex of the structure at the end by a predetermined distance shorter than the minimum sidewalk width and the apex is set, and the surface point having the longest perpendicular line to the straight line is set. The structure lower end point extraction means to be extracted as the structure lower end point and the average point of the surface points in the range of the predetermined distance from the structure lower end point are determined, and a straight line connecting the average point and the running point is drawn. A road end point extracting means for setting and extracting the surface point having the longest perpendicular to the straight line as a road end point, and a road end determining means for connecting the road end points in each cross section to determine the road end. And have.

Therefore, it is possible to accurately identify the end of the road by distinguishing between the sidewalk and the roadway.

(2) (4) The road feature determining device according to the present invention includes a road center point extracting means that extracts the midpoint between the left and right road end points in the cross section as a road center point, and a road center point in each cross section. It is equipped with a road center determination means for determining the road center line by connecting the roads.

Therefore, the road center line can be accurately determined.

(5) (7) (15) (17) The road feature determining device according to the present invention extracts a division line extraction that extracts points of surface points having a predetermined brightness or more that are continuous for a predetermined distance or more as a division line. The means and the dividing line determining means for determining the dividing line by complementing the missing portion of the dividing line are provided.

Therefore, it is possible to accurately obtain a dividing line that divides lanes.

(6) (8) (16) (18) The road feature determining device according to the present invention determines the lane center line at the center of the dividing line and the road end or at the center of the adjacent dividing line. It has the means.

Therefore, the lane center line can be accurately obtained.

(9) (19) In the road feature determining device according to the present invention, the dividing line determining means divides the division line based on the distance between the left and right road ends and the minimum lane width in the section where the dividing line cannot be extracted. It is characterized by generating lines.

Therefore, the lane can be estimated even on a road without a white line or a yellow line.

(10) (11) (20) (21) The road characterization device according to the present invention creates straight lines and arcs based on the road centerline or lane centerline in the vicinity of the curve extracted based on the three-dimensional measurement data. A clothoid curve is set from the straight line / arc extraction means to be extracted and the center of the arc with respect to the straight line, and the center of the arc is set as the center of the radius of curvature at the end point of the clothoid, and the tangent angle to the perpendicular is changed. Is generated, and the clothoid curve determining means for determining the clothoid curve whose clothoid end point matches the arc, and the end point of the straight line and the end point of the arc are determined based on the determined clothoid curve, and the straight line, the clothoid curve, and the arc are determined. It is equipped with a connection means for connecting.

Therefore, a straight line and an arc of the center line can be connected by an appropriate clothoid curve.

(12) (22) In the road feature determining device according to the present invention, the clothoid curve determining means depends on whether or not the position of the clothoid end point perpendicular to the straight line matches the position of the end point of the arc with respect to the straight line. It is characterized by determining the clothoid curve.

Therefore, an appropriate clothoid curve can be determined.

(13) (14) (23) (24) The road feature determining device according to the present invention has a road end line extracted based on three-dimensional measurement data on the right side of a traveling line connecting the traveling trajectories. The classification means for classifying into the right road end line and the left road end line on the left side, and the position where the right road end line and the left road end line meet are set as the branch start position, and the straight line is extended from the branch start position. , A branch range determination means whose branch end position is the position where the straight line touches the road end line, and both road center lines or lane center lines are extended from the branch start position to the branch end position to generate the branch end position. In, a central line generating means for generating a road center line or a lane center line so as to connect both road center lines is provided.

Therefore, the center line can be connected even at the branch portion.

In the embodiment, step S1 corresponds to the “cross-section setting means”.

In the embodiment, steps S15 and S17 correspond to the "running point determining means".

In the embodiment, steps S34 to S37 correspond to the “structure lower end point extraction means”.

In the embodiment, steps S43 to S47 correspond to the “road end point extraction means”.

In the embodiment, step S7 corresponds to the “road end determination means”.

The "program" is a concept including not only a program that can be directly executed by the CPU, but also a source format program, a compressed program, an encrypted program, and the like.

It is a functional block diagram of the road feature determination apparatus according to 1st Embodiment of this invention. This is the hardware configuration of the road characterization device. It is a flowchart of a road end / center determination process. It is a flowchart of the cross section setting process. This is an example of three-dimensional measurement data. This is an example of point cloud data projected on the cross section. It is a flowchart of a road end point extraction process. It is a flowchart of a road end point extraction process. It is a figure for demonstrating the road end point extraction process. It is a functional block diagram of the road feature determination device by 2nd Embodiment. It is a flowchart of the division line / lane center line determination process. It is a figure for demonstrating the division line extraction process. It is a figure for demonstrating the division line determination process by another example. It is a functional block diagram of the road feature determination device according to 3rd Embodiment. It is a flowchart of a center line connection process. It is a flowchart of a center line connection process. It is a flowchart of a center line connection process. It is a figure for demonstrating the connection of a straight line in a plane. .. It is a figure for demonstrating the connection of a straight line in a vertical cross section. .. It is a figure for demonstrating the connection of a straight line and an arc. It is a figure for demonstrating the connection of a straight line and an arc. It is a figure for demonstrating the connection of an arc and an arc. It is a functional block diagram of the road feature determination device according to 4th Embodiment. It is a flowchart of a branch process. It is a flowchart of a branch part identification / center line completion process. It is a flowchart of a branch part identification / center line completion process. It is a figure for demonstrating the connection of the center line in a branch part. It is a figure for demonstrating the connection of the center line in a branch part. It is a figure for demonstrating the connection of the center line in a branch part. It is a figure for demonstrating the connection of the center line at an intersection.

1. 1. First Embodiment
1.1 Overall Configuration Figure 1 shows a functional block diagram of the road feature determination device according to an embodiment of the present invention.

The road feature determination device in this embodiment determines the road edge and the road center by receiving three-dimensional measurement data from surface points measured while traveling on the road.

The cross-section setting means 2 sets cross-sections perpendicular to the traveling direction at predetermined intervals in the three-dimensional measurement data. The traveling point determining means 4 determines the intersection of the traveling line connecting the traveling locus and the cross section as the traveling point.

The structure lower end point extracting means 6 finds a surface point in a cross section at a position moved horizontally by a predetermined distance shorter than the minimum sidewalk width from the apex of the structure at the end. A straight line connecting the found surface point and the apex is set. Further, the surface point having the longest perpendicular to the straight line is extracted as the lower end point of the structure.

The road end point extracting means 8 determines an average point of surface points within a predetermined distance from the lower end point of the structure, and sets a straight line connecting the average point and the traveling point. Further, the surface point having the longest perpendicular to the straight line is extracted as the road end point. In this way, road end points are extracted in each cross section.

The road end determination means 10 connects the road end points in each cross section to generate a road end line, and determines the road end. Thereby, the shape of the road end can be continuously obtained.

Further, the road center point extracting means 12 extracts the midpoint between the left and right road end points in each cross section as the road center point. The road center determining means 14 determines the road center line by connecting the road center points in each cross section.

1.2 Hardware configuration Figure 2 shows the hardware configuration of the road characterization device. A memory 32, a display 34, a hard disk 36, a CD-ROM drive 38, and a keyboard / mouse 40 are connected to the CPU 30.

The operating system 42 and the road feature determination program 44 are recorded on the hard disk 36. The road characterization program 44 exerts its function in cooperation with the operating system 42.

These programs are those recorded on the DVD-ROM 46 installed on the hard disk 36 via the CD-ROM drive 38. It may be downloaded and installed from a server device (not shown) via the Internet.

1.3 Road edge / center determination process
1.3.1 Overall Flowchart Figure 3 shows the overall flowchart of the road end / center determination process of the road feature determination program 44.

The CPU 30 reads the three-dimensional measurement data from a DVD-ROM or the like and records it on the hard disk 36. The three-dimensional measurement data is obtained by loading a radar ranging device on an automobile, an unmanned aerial vehicle (UAV), or the like and measuring while traveling, and is data showing the surface shape near the road. Further, the three-dimensional measurement data includes data of a traveling point indicating the position of the automobile by changing with time. As the three-dimensional point cloud data, for example, MMS point cloud data can be used.

The CPU 30 reads the three-dimensional measurement data from the hard disk 36 and sets the cross section at predetermined intervals (step S1). Subsequently, the CPU 30 extracts the left end point of the road in each set cross section (step S3). Further, in each of the set cross sections, the right end point of the road is extracted (step S4). Next, the CPU 30 extracts the center of the left end point and the right end point as the center point in each cross section (step S5).

When the CPU 30 extracts the left end point, the right end point, and the center point for all the cross sections, the CPU 30 connects them to determine the left end line, the right end line, and the center line (step S6).

Details will be described below for each process.

1.3.2 Cross-section setting FIG. 4 shows a detailed flowchart of the cross-section setting process (step S1). FIG. 5 shows an example in which three-dimensional measurement data is schematically shown. The surface shape of the road is represented by a large number of measurement points. In this embodiment, the measurement data of each point includes the three-dimensional coordinates of X, Y, and Z, the reflection intensity, and the measurement time. Further, the three-dimensional coordinates of X, Y, and Z of the traveling position (traveling point) of the vehicle and the measurement time are also included. The Z coordinate in the height direction is obtained as above sea level.

The CPU 30 connects the traveling points with a line in the order of measurement time to generate a traveling line (steps S11 to S14). Next, the CPU 30 draws a perpendicular line from each measurement point to the traveling line to generate an intersection (step S17). The CPU 30 groups each measurement point into one group for each predetermined distance (for example, every 10 cm) based on the distance from the starting point of the traveling line to the intersection (step S19). The grouped measurement points provide measurement points in a cross section (a plane perpendicular to the running line). Further, the point where the traveling line touches the cross section is obtained as the traveling point.

FIG. 6 shows an example of measurement points in the cross section. In this example, there is a road part and a sidewalk part, and there is a structure at the end. However, in the measurement data, only the shape shown in FIG. 6 can be directly known. Therefore, the CPU 30 obtains which part is the road part and which part is the sidewalk part by the road end point extraction process described later.

In this embodiment, the measurement points are grouped every 10 cm. However, the cross section may be set at predetermined intervals along the traveling line, and the measurement points whose vertical distance to the cross section is within 5 cm may be vertically moved to move to the cross section.

1.3.3 Extraction of road end points FIGS. 7 and 8 show detailed flowcharts of road end point extraction processes (steps S3 and S4). The CPU 30 extracts the apex A at the left end of each cross section (see FIG. 9A). Further, a point B located at a position moved inward from this apex by a predetermined distance (for example, 0.5 m) in the X direction is extracted. The CPU 30 sets a straight line connecting the apex A and the point B (step S31).

The CPU 30 generates a perpendicular line with respect to the straight line for each measurement point within the range of the apex A and the point B, and calculates the distance thereof (step S34). Then, the measurement point having the largest vertical distance is found and set as the feature point C at the lower part of the structure (steps S35, S36, S37).

As described above, the feature point C on the left side is found. The CPU 30 similarly finds the feature point C on the right side.

Next, as shown in FIGS. 9B and 9C, the CPU 30 extracts measurement points within a predetermined distance (for example, 0.5 m) in the X direction and within a predetermined distance (for example, 0.1 m) in the Z direction from the feature point C. Then, the average value of the X, Y, and Z coordinates is calculated, and the temporary point D is obtained (step S39).

The CPU 30 connects the temporary point D and the running point with a straight line (step S40). Next, the CPU 30 calculates the vertical distance from the straight line for each measurement point between the temporary point D and the running point E (step S43) (step S44). The measurement point having the largest vertical distance is found and set as the road end point F (steps S45, S46, S47). Although FIG. 9 describes the determination of the road end point F on the left side, the road end point F on the right side is also determined in the same manner.

1.3.4 Determining the road center point Then, as shown in FIG. 9D, the CPU 30 averages the coordinates of the left side road end point and the right side road end point in each cross section, and the road center point G (the X coordinates of both points). (Having an average value) is calculated (step S5 in FIG. 3).

By each of the above processes, the left side road end point, the right side road end point, and the road center point can be obtained in each cross section.

1.3.5 Determining the road end line / road center line The CPU 30 connects the left side road end point and the right side road end point in each cross section with a line to obtain the left side road end line and the right side road end line. Further, the road center points are connected by a line to obtain the road center line (step S7).

1.4 Other
(1) In the above embodiment, the road center line is obtained in addition to the left and right road end lines. However, only one of the road end line and the road center line may be obtained.

(2) In the above embodiment, the case where there are sidewalks at both ends of the road has been described. In the case of a road without a sidewalk, the feature point C may be extracted as it is as a road end point. Further, when the Z coordinate of the temporary point D is smaller than the Z coordinate of the running point E, or when the difference between the Z coordinates of the temporary point D and the running point E is less than a predetermined value (for example, 1 cm), You can judge that there is no sidewalk.

(3) In the above embodiment, the road end line and the road center line are determined. In addition to or instead of this, the cross slope of the road may be determined. It can be determined by calculating the slope of a straight line connecting the left and right road end lines in the cross section.

(4) In the above embodiment, the road feature determination device is configured as a stand-alone PC. However, it may be configured as a server device. In this case, the three-dimensional measurement data may be transmitted from a terminal device connected via the Internet or the like to a server device which is a road feature determining device. Further, the determined road end line and road center line are transmitted from the server device to the terminal device.

(5) In FIGS. 9A and 9B, a point for drawing a straight line is provided inside 0.5 m. However, if the length is smaller than the width of the sidewalk, it may be larger or smaller.

(6) The above modified examples can be carried out in combination with each other. In addition, the present embodiment and modifications can be applied to other embodiments as long as the essence is not contrary to the essence.

2. Second embodiment
2.1 Overall Configuration Figure 10 shows a functional block diagram of the road feature determining device according to the second embodiment of the present invention.

The road feature determining device in this embodiment receives three-dimensional measurement data from surface points measured while traveling on the road, and determines a lane dividing line and a lane center line.

The dividing line extracting means 20 extracts a portion where the reflection intensity (luminance) is equal to or higher than a predetermined value and continues for a predetermined length as a lane dividing line based on the three-dimensional measurement data. The dividing line determining means 22 complements the missing portion of the lane dividing line based on the intermittent lane dividing line, and determines the dividing line.

The road end line determining means 26 determines the end line of the road based on the three-dimensional measurement data. As the road end line determining means 26, the method according to the first embodiment can be used. When the lane dividing line due to the brightness difference is not extracted, the dividing line determining means 22 determines the lane dividing line based on the road width obtained based on the road end line.

The lane center line determining means 24 determines the lane center line based on the lane dividing line and the road end line.

The lane center line determined in this way can be used for automatic driving control of an automobile or the like.

2.2 Hardware configuration The hardware configuration of the road feature determination device according to this embodiment is the same as in FIG.

2.3 Dividing line / lane center determination processing The flowchart in the lane dividing line / lane center line determining processing of the road feature determination program 44 is shown.

The CPU 30 extracts a portion larger than a predetermined brightness for each point of the three-dimensional measurement data. If a white line or a yellow line is drawn on the road to divide the lane, the reflection at this part becomes large and the brightness becomes higher than the surroundings. Therefore, the lane dividing line can be extracted by extracting the portion having high brightness over a predetermined length or longer.

For example, as shown in FIG. 12B, a white line or a yellow line can be extracted. In FIG. 12B, the intermittent lane division region R is extracted. The cross section is as shown in FIG. 12A. If the high-luminance portion does not continue for a predetermined length or longer as in the region RE, it is not extracted.

As shown in FIG. 12B, when the lane division region R of the white line or the yellow line is detected (step S81), the CPU 30 sets the center of the region R in the road width direction as the lane division point. The CPU 30 connects the lane dividing points in each cross section to determine the lane dividing line DL (step S82).

If the white line or yellow line is intermittent, in the part where there is no white line or yellow line, it is assumed that there is a white line or yellow line at the distance d from the road end to the white line / yellow line in the vicinity. (See FIG. 12C).

In some cases, the white and yellow lines are not drawn and these cannot be extracted. In this case, the CPU 30 determines the lane dividing line DL as follows based on the road width D (step S83). First, based on the three-dimensional measurement data, the left and right road end points in each cross section are determined based on the process of FIG. Further, the road width D is calculated based on the left and right road end points (see FIG. 13A). If the road end point and the road width D are given, they may be used.

The CPU 30 calculates D / d based on the road width D and the predetermined minimum lane width d, rounds down a small number or less, and calculates the number of lanes C. For example, if the road width D is 8.5 m and the set minimum lane width d is 2.75 m, the D / d is 3.09 (see FIG. 13B). This is rounded down and 3 is obtained as the number of lanes C. The minimum lane width d may be changed depending on the type of road (general road or expressway).

Next, the CPU 30 calculates the lane width by dividing the road width D by the number of lanes, thereby determining the lane division point (see FIG. 13C). The lane division line is determined by connecting the lane division points of each cross section.

As described above, if there is a white line or a yellow line, the lane dividing line is determined based on the white line or the yellow line, and if not, the lane dividing line is determined based on the road width D. When the lane dividing line is determined, the CPU 30 determines the lane center line at the center of each lane as shown in FIG. 13D (step S84).

2.4 Others (1) In the above embodiment, the lane dividing line is complemented for the portion without the white line / yellow line based on the distance d from the road end in the portion with the nearby white line / yellow line. .. However, the lane dividing line in the part with the white line and the yellow line may be connected to complement the lane.

(2) The above modified examples can be carried out in combination with each other. In addition, the present embodiment and modifications can be applied to other embodiments as long as the essence is not contrary to the essence.

3. 3. Third Embodiment
3.1 Overall Configuration Figure 14 shows a functional block diagram of the road feature determining device according to the third embodiment of the present invention.

The road feature determining device in this embodiment receives three-dimensional measurement data from surface points measured while traveling on the road, and determines a straight line, an arc, and a clothoid curve of the lane center line.

The straight line / arc extracting means 30 receives the three-dimensional measurement data and extracts the straight line and the arc of the lane center line. The clothoid curve determining means 32 sets a perpendicular line from the center of the arc to the straight line, sets the center of the arc as the center of the distance rate radius at the end point of the clothoid, and changes the tangent angle to the perpendicular to obtain the clothoid curve. A clothoid curve that is generated and whose clothoid end point matches the arc is determined. The connecting means 34 determines the end point of the straight line and the end point of the arc based on the determined clothoid curve, and connects the straight line, the clothoid curve, and the arc.

As described above, the degree of bending including the clothoid curve in the curved portion can be accurately determined.

3.2 Hardware configuration The hardware configuration of the road feature determination device according to this embodiment is the same as in FIG.

3.3 Curve section determination process FIGS. 15 to 17 show a flowchart in the center line connection process including the curve section determination process of the road feature determination program 44. The CPU 30 determines the road center point or the lane center point based on the three-dimensional measurement data (step S91). This can be achieved, for example, by the processes shown in the first embodiment and the second embodiment.

Next, the CPU 30 extracts a straight line portion by Hough transform (step S92). The center point extracted as this straight line is removed from the judgment target (step S93). Subsequently, the CPU 30 extracts the arc portion by the RANSAC method (step S94). Further, in order to remove noise, each line is grouped and the group having a small number of points is deleted (step S95).

Subsequently, the CPU 30 performs the following processing for each line. First, the CPU 30 determines whether or not the line to be processed is a straight line (step S97). If it is a straight line, its gradient (angle in the vertical section) is calculated (step S98). If it is an arc, the coordinates of the center point of the circle and the radius are calculated (step S99).

When the gradient of the straight line and the center coordinates / radius of the circle are calculated for all the lines as described above, the CPU 30 executes the following processing for each line. First, the CPU 30 determines whether the line to be processed is a straight line (step S103). If the target line is a straight line, it is determined whether the next adjacent line is a straight line (step S104). If the next line is a straight line, it means that the straight line and the straight line are continuous, so complement processing between the straight lines is performed (step S106).

Complementary processing between straight lines is shown in FIGS. 18A, B, and C. First, the CPU 30 extends both straight lines to obtain the intersection (FIG. 18A). Furthermore, a perpendicular line is drawn from the end point of one of the straight lines. Also, from the intersection of both straight lines, draw a straight line that divides the angle formed by both straight lines into two equal parts. Find the point where this perpendicular and the bisector intersect (Fig. 18B). An arc is drawn with this intersection as the center point (FIG. 18C). An arc is provided up to the point where the other straight line intersects this arc. If the other straight line and the arc do not intersect, the other straight line is extended so that the other straight line and the arc intersect. In this way, the joint between straight lines is complemented in the XY plane.

Further, also in the YZ plane (longitudinal cross section), the joint portion between the straight lines is complemented. The CPU 30 extends both straight lines in the vertical cross section and finds the intersection thereof (FIG. 19A). Further, a parabola that passes through a point d away from the intersection and tangent to both straight lines is generated (FIG. 19B).

If the target line is a straight line (YES in step S103) and the next line is a curve (NO in step S104), complementation is performed to join the straight line and the curve by the clothoid curve (step S107). ..

As shown in FIG. 20A, the straight line portion and the arc do not contact each other. This is because in the curve of the road, the straight line and the arc are not connected, but the clothoid curve is provided between them. Therefore, the CPU 30 estimates the clothoid curve in step S107.

First, as shown in FIG. 20B, the CPU 30 determines the most appropriate clothoid curve while changing the parameters of the clothoid curve. Further, as shown in FIG. 20C, the straight line and the arc are connected by the determined clothoid curve.

21A, B, and C show details of the process for showing an appropriate clothoid curve. First, the CPU 30 draws a perpendicular line from the center M of the arc with respect to the straight line (FIG. 21A). Next, as shown in FIG. 21B, a clothoid curve is generated with a point on a straight line as a clothoid start point and a position at an angle τ with a perpendicular line as a clothoid end point. At this time, the clothoid curve is generated while changing the angle τ from 0 to 90 at 0.01 intervals.

The CPU 30 finds a clothoid curve in which the distance Y from the clothoid start point of the clothoid end point of the clothoid curve generated by changing the angle τ and the distance d from the straight line to the arc match. Further, as shown in FIG. 21C, based on the found clothoid curve, the clothoid start point S is set as the end point of the straight line, and the straight line and the arc are joined by the clothoid curve.

Further, when the target line is a curve (step S103 is NO) and the next line is a curve (step S104 is NO), complementation is performed to join the curve to the curve (step S108). Details of the process are shown in FIG.

The CPU 30 sets a straight line connecting the arc and the center point of the arc. Further, this straight line is extended to the side of the arc having the smaller radius, and a point is set at the position D from the arc. D is determined by the following formula.

D = original straight line distance x small circle radius / (large circle radius-small circle radius)
The CPU 30 draws a straight line tangent to the two arcs from the set point. This straight line connects the arc to the arc.

3.4 Others
(1) In the above embodiment, the joining of the lane center lines has been described. However, the same can be applied to the road center line and the road end line.

(2) The above modified examples can be carried out in combination with each other. In addition, the present embodiment and modifications can be applied to other embodiments as long as the essence is not contrary to the essence.

4. Fourth Embodiment
4.1 Overall configuration FIG. 23 shows a functional block diagram of the road feature determining device according to the fourth embodiment of the present invention.

The road characterization device in this embodiment processes the center line at the branch portion. The classification means 40 classifies the road end line into a right road end line on the right side of the traveling line and a left road end line on the left side of the traveling line. The branch range determining means 42 sets the position where the right side road end line and the left side road end line meet as the branch start position. Further, a straight line is extended from the branch start position, and the position where the straight line touches the road end line is set as the branch chief position.

The center line generating means 44 extends both road center lines or lane center lines from the branch start position to the branch end position. In addition, a road center line or lane center line is generated so as to connect both road center lines at the branch end position.

4.2 Hardware configuration The hardware configuration of the road feature determination device according to this embodiment is the same as in FIG.

4.3 Branch processing Fig. 24 shows a flowchart of branch processing of the road feature determination program. The CPU 30 first identifies the branch portion (step S110). Further, a branch section is specified for each of the specified branch portions (step S112). Subsequently, the center line is connected in the branch section (step S113). In this way, the center line can be complemented at the branch portion.

25 and 26 show the details of steps S112 and S113. The CPU 30 determines whether each road end line is on the right side or the left side of the traveling line (step S120). As shown in FIG. 27A, record whether it is on the right side or the left side. Next, each road end line is grouped by those connected to each other (step S121).

The CPU 30 performs the following processing for each cluster generated above. First, it is determined whether or not there are both the right side road end line and the left side road end line in the cluster (step S123). As shown in FIG. 27B, since the cluster 2 has both, it can be determined that the cluster 2 is a branch. Further, the intersection Z (see FIG. 27C) on the right side and the left side is set as the branch start point (step S124). The branch can be extracted as described above to determine the starting point.

The CPU 30 determines whether or not the number of lanes changes at the branch portion for each branch (step S130). For example, as shown in FIG. 28A, if the number of lanes does not change at the branch portion, the center line is drawn well and no special processing is performed. However, as shown in FIGS. 28B and 28C, if the number of lanes changes at the branch portion, the CPU 30 complements the center line as shown below.

First, a straight road boundary line is extended from the branch start point Z as shown in FIGS. 29A and 29B (step S131). Further, the CPU 30 obtains an intersection Q between the extended straight line and another road boundary line, and sets it as the branch end point (step S132).

The CPU 30 extends both center lines at the branch portion from the branch start point Z to the branch end point Q (step S134). At the branch end point Q, the end points of both center lines are connected by a straight line K (see FIG. 29A). In addition, as shown in FIG. 29B, when both center lines are connected only by extending the center line, it is left as it is.

Further, as shown in FIG. 30, although the road center line and the lane center line are interrupted at the intersection, the connection can be made by the same method as described above.

4. The present embodiment can be applied to other embodiments as long as it does not contradict the essence of the present.

Claims (6)

It is a road feature determination device that determines road features based on three-dimensional measurement data of surface points measured while traveling on the road.
A straight line / arc extraction means for extracting straight lines and arcs based on the road center line or lane center line in the vicinity of the curve extracted based on the three-dimensional measurement data.
From the center of the arc, a perpendicular line is set with respect to the straight line, the center of the arc is set as the center of the radius of curvature at the clothoid end point, the tangential angle with respect to the perpendicular line is changed, and the junction point between the arc and the clothoid curve is changed. A clothoid curve determining means for generating a clothoid curve and determining a clothoid curve whose end point coincides with the arc.
Based on the determined clothoid curve, the end point of the straight line and the end point of the arc are determined, and the connecting means for connecting the straight line, the clothoid curve, and the arc is used.
Road characterization device equipped with. In the apparatus of claim 1,
The clothoid curve determining means is an apparatus for determining a clothoid curve depending on whether or not the position of the end point of the clothoid perpendicular to the straight line matches the position of the end point of the arc that is perpendicular to the straight line. In the apparatus of claim 1 or 2,
A classification means for classifying the road end line extracted based on the three-dimensional measurement data into a right road end line on the right side of the traveling line connecting the traveling trajectories and a left road end line on the left side. ,
A branch range determination means in which the position where the right side road end line and the left side road end line meet is set as the branch start position, a straight line is extended from the branch start position, and the position where the straight line touches the road end line is set as the branch end position. ,
Generated by extending both road center lines or lane center lines from the branch start position to the branch end position, and at the branch end position, generate the road center line or lane center line so as to connect both road center lines. Line generation means and
A device further equipped with. It is a road feature determination program for realizing a road feature determination device that determines road features based on three-dimensional measurement data of surface points measured while traveling on the road, and the computer is described as three-dimensional. A straight line / arc extraction means that extracts straight lines and arcs based on the road center line or lane center line in the vicinity of the curve extracted based on the measurement data.
From the center of the arc, a perpendicular line is set with respect to the straight line, the center of the arc is set as the center of the radius of curvature at the clothoid end point, the tangential angle with respect to the perpendicular line is changed, and the junction point between the arc and the clothoid curve is changed. A clothoid curve determining means for generating a clothoid curve and determining a clothoid curve whose end point coincides with the arc.
A road feature determination program for determining the end points of the straight line and the arc based on the determined clothoid curve and functioning as a connecting means for connecting the straight line, the clothoid curve, and the arc. In the program of claim 4,
The clothoid curve determining means is a program characterized in that the clothoid curve is determined depending on whether or not the position of the end point of the clothoid perpendicular to the straight line matches the position of the end point of the arc that is perpendicular to the straight line. In the program of claim 4 or 5, the computer is further added.
A classification means for classifying the road end line extracted based on the three-dimensional measurement data into a right road end line on the right side of the traveling line connecting the traveling trajectories and a left road end line on the left side. ,
A branch range determination means in which the position where the right side road end line and the left side road end line meet is set as the branch start position, a straight line is extended from the branch start position, and the position where the straight line touches the road end line is set as the branch end position. ,
Generated by extending both road center lines or lane center lines from the branch start position to the branch end position, and at the branch end position, generate the road center line or lane center line so as to connect both road center lines. A program to function as a line generation means.

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