JP2017146530A - Map data generation device, map data generation method, and map data generation program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a map data generation device capable of generating map data that optimally expresses a road shape and has a small amount of data.SOLUTION: A map data generation device 3 includes: a shape determination unit 35 for classifying a road whose road shape is expressed by first shape data that expresses the road shape by a plurality of points into a straight line section and a curved line section; a point sequence thinning-out unit 36 for changing expression of the road shape of the straight line section into expression by first expression; a curved line unit 37 for changing the road shape of the curved line section into expression by the second expression different from the first expression; and an output unit 332 for outputting data of the road shape by expression changed by the point sequence thinning-out unit and the curved line unit as second shape data.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a map data generation device, a map data generation method, and a map data generation program.

  Conventionally, a map data format that expresses the geometric shape of a road by a parametric curve is known (for example, Patent Document 1).

Japanese Patent No. 5591444

  The prior art has a problem that the amount of data cannot be sufficiently reduced for a road having a straight shape.

According to the first aspect of the present invention, the map data generation device classifies the road in which the road shape is expressed by the first shape data that expresses the road shape by a plurality of points into straight sections and curved sections. Part, a point sequence thinning unit that changes the expression of the road shape of the straight section to the expression by the first expression, and the expression of the road shape of the curved section to the expression by the second expression different from the first expression A curving unit, and an output unit that outputs road shape data based on the expression changed by the point sequence thinning unit and the curving unit as second shape data.
According to the second aspect of the present invention, the map data generation method is a shape determination for classifying a road in which the road shape is expressed by the first shape data expressing the road shape by a plurality of points into a straight section and a curved section. A step, a point sequence thinning step for changing the expression of the road shape of the straight section to the expression by the first expression, and a change of the expression of the road shape of the curved section to the expression by the second expression different from the first expression A curving step, and an output step of outputting road shape data based on the expression changed by the point sequence thinning step and the curving step as second shape data.
According to the third aspect of the present invention, the map data generation program classifies the road in which the road shape is expressed by the first shape data that expresses the road shape by a plurality of points into a straight section and a curved section. A step, a point sequence thinning step for changing the expression of the road shape of the straight section to a first expression, and a change of the expression of the road shape of the curved section to a second expression different from the first expression. And a step of outputting the road shape data by the point sequence thinning step and the expression changed by the curving step as the second shape data.

  According to the present invention, map data with a small amount of data can be generated.

Schematic diagram of the vehicle control system according to the first embodiment Block diagram showing the hardware configuration of the map data generation device Block diagram showing the functional configuration of the map data generation device The figure which illustrates the 1st shape data Explanatory drawing of the shape determination process by a shape determination part Explanatory drawing of the point sequence thinning process by the point sequence thinning unit Explanatory drawing of curving process by curving unit Illustration of lane expression change processing by lane expression change unit The figure which illustrates the 2nd shape data Flow chart of map data generation processing The figure which illustrates the 1st shape data

(First embodiment)
FIG. 1 is a schematic diagram of a vehicle control system 1 according to a first embodiment of the present invention. The vehicle control system 1 includes a map data generation device 3 and a vehicle 5. The map data generation device 3 creates vehicle control map data 4 by executing map data generation processing described later on the input base map data 2. The base map data 2 is map data including information on at least a road. In the base map data 2, the shape of a plurality of lanes (lanes) constituting a road is expressed by a plurality of points specified by, for example, latitude and longitude. The vehicle control map data 4 is map data that is created based on the base map data 2 and includes at least information about roads. Although details will be described later, the vehicle control map data 4 represents a road shape equivalent to the base map data 2 with a smaller data amount than the base map data 2.

  A vehicle control device 6 is mounted on the vehicle 5. The vehicle control device 6 controls the vehicle 5 based on the vehicle control map data 4 generated by the map data generation device 3. For example, the vehicle control device 6 performs autonomous operation control of the vehicle 5 based on the outputs of various sensors (not shown) mounted on the vehicle 5 and the map data 4 for vehicle control. The vehicle control device 6 performs autonomous operation control of the vehicle 5 by acquiring road information necessary for vehicle control (for example, acceleration, deceleration, steering, etc.) from the vehicle control map data 4.

  The vehicle control map data 4 is stored in advance in a storage medium (not shown) included in the vehicle control device 6, for example. Or the map data 4 for vehicle control is transmitted to the vehicle control apparatus 6 via communication channels, such as a mobile telephone network, for example from the server not shown.

  FIG. 2 is a block diagram illustrating a hardware configuration of the map data generation device 3. The map data generation device 3 includes a storage unit 31, a calculation unit 32, and a data input / output unit 33.

  The storage unit 31 is a storage device such as a hard disk drive. The storage unit 31 includes a first storage area 311 that stores base map data 2 that is input data, and a second storage area 312 that stores vehicle control map data 4 that is output data.

  The data input / output unit 33 includes a data input unit 331 and a data output unit 332. The data input unit 331 reads the base map data 2 from the first storage area 311 and inputs it to the calculation unit 32. The data output unit 332 writes the vehicle control map data 4 output from the calculation unit 32 in the second storage area 312.

  The calculation unit 32 performs map data generation processing described later on the base map data 2 input by the data input unit 331 and outputs the vehicle control map data 4 to the data output unit 332.

  The base map data 2 includes first shape data 21, lane number data 22, lane width data 23, and road attribute data 24. The first shape data 21 is data indicating a road shape by a plurality of points specified by, for example, latitude and longitude. The first shape data 21 includes the shape of each lane for roads including a plurality of lanes (lanes). The lane number data 22 is data indicating the number of lanes (lane number) of the road. The lane width data 23 is data indicating the width of one road lane (lane).

  The road attribute data 24 is data indicating road attributes such as branch and merge start and end points, lane increase / decrease start and end points, toll gate, tunnel, and lane type. Note that data corresponding to the lane number data 22 and the lane width data 23 may be included in the road attribute data 24.

  The vehicle control map data 4 includes second shape data 41, lane number data 42, lane width data 43, and road attribute data 44. The second shape data 41 is data indicating a road shape. Although details will be described later, the second shape data 41 has an expression format different from that of the first shape data 21 so that the data size is smaller than that of the first shape data 21. Since the lane number data 42, the lane width data 43, and the road attribute data 44 are the same as the data having the same name included in the base map data 2, description thereof will be omitted.

  FIG. 3 is a block diagram illustrating a functional configuration of the map data generation device 3. The map data generation device 3 includes a shape determining unit 35, a point sequence thinning unit 36, a curving unit 37, and a lane expression changing unit 38.

  The shape determination unit 35 classifies roads included in the first shape data 21 input to the data input unit 331 into straight sections and curved sections. In other words, the shape determination unit 35 determines a point where the road shape changes from a straight line to a curve and a point where the road shape changes from a curve to a straight line, and divides the road at each point.

  Although the details will be described later, the shape determination unit 35, even if it is a continuous straight section and a curved section, if a plurality of sections having different road attributes are included in the section, the plurality of sections Are classified as individual straight sections and curved sections. In other words, each straight section and curved section classified by the shape determination unit 35 has a common road attribute. In the present embodiment, road sections having different road attributes are classified as different straight sections and curved sections, respectively.

  The point sequence thinning unit 36 performs a point sequence thinning process to be described later on the road shape of the straight section classified by the shape determining unit 35. By the point sequence thinning process, the road shape of the straight section is expressed by a smaller number of points, and the data amount is reduced.

  The curving unit 37 performs a curving process to be described later on the road shape of the curved section classified by the shape determining unit 35. By the curving process, the road shape of the curve section is expressed by a smaller number of points (control points), and the data amount is reduced.

  The lane expression changing unit 38 executes a lane expression changing process, which will be described later, on the road shape data output by the point sequence thinning process or the curving process. By the lane expression changing process, road shape data of a plurality of lanes existing in one straight section or one curved section is changed to a reference lane expression described later if possible. By using the reference lane expression, the amount of road shape data is further reduced. The road shape data changed to the reference lane representation is output to the data output unit 332.

  Hereinafter, map data generation processing executed by the map data generation device 3 will be described with reference to FIGS. The map data generation process includes a shape determination process by the shape determination unit 35, a point sequence thinning process by the point sequence thinning unit 36, a curving process by the curving unit 37, and a lane expression change process by the lane expression change unit 38. Including.

  FIG. 4A is a diagram illustrating a data structure of the first shape data 21, and FIG. 4B is a diagram illustrating a road shape represented by the first shape data 21. As shown in FIG. 4A, the first shape data 21 is data including a plurality of points 104 expressed by longitude 101 and latitude 102. As shown in FIG. 4B, each point 104 is located on the center line 107 of each lane 106 included in the road 105. That is, the first shape data 21 is data representing the road shape by representing the center line 107 of each lane 106 by a plurality of points 104.

  FIG. 5 is an explanatory diagram of the shape determination process performed by the shape determination unit 35. The shape determination unit 35 classifies roads included in the base map data 2 for each section having common road attributes. The road 108 in the expressway illustrated in FIG. 5 has five sections, a first section 111, a second section 112, a third section 113, a fourth section 114, and a fifth section 115, from the bottom to the top of the page. It is divided into. The first section 111 is a straight section of the main road. The second section 112 is a branch start section to the deceleration lane. The third section 113 is a straight section including a deceleration lane. The fourth section 114 is a ramp way section heading to the exit. The fifth section 115 is a straight section of the main road. The second section 112 is different from the first section 111 and the third section 113 in that the second section 112 includes an oblique deceleration lane, and thus is different from the first section 111 and the third section 113. It is classified as a section.

  The shape determination unit 35 classifies each section divided based on the road attribute as either a straight section or a curved section. One whole section divided based on road attributes may be classified into one straight section or curved section, or one section is further divided into a plurality of sections, each of which is divided into a straight section and a curved section. May be classified.

  For example, the shape determination unit 35 divides one section into a plurality of parts, and obtains a curvature and a curvature radius for each part. If the radius of curvature is equal to or greater than a predetermined length (for example, 1000 m), the portion is determined to be a linear shape. If it is less than a predetermined length (for example, 1000 m), it is determined that the portion has a curved shape. If all the shapes in the section are straight lines, the section is classified as one straight section as a whole. If all the shapes in the section are curves, the section is classified into one curve section as a whole. When the straight line shape and the curved line shape are switched between successive portions in the section, the shape determination unit 35 divides the section there, and classifies one as a straight section and the other as a curved section.

  FIG. 6 is an explanatory diagram of the point sequence thinning process by the point sequence thinning unit 36. The point sequence thinning unit 36 reduces the capacity of the road shape data for each road section determined as a straight section by the shape determination unit 35. The point sequence thinning unit 36 reduces the data capacity of the linear shape by using, for example, a well-known Douglas-Peuker algorithm. For example, the point sequence thinning unit 36 connects the start point and the end point with a straight line in the shape data of one section, and searches for a point farthest from the straight line. The point sequence thinning unit 36 measures the distance from the point farthest away to the straight line, and when the distance exceeds a predetermined distance, the point is set as a point to be left after thinning. Next, the point sequence thinning unit 36 searches for a straight line connecting the start point and the above point and a point farthest from the straight line connecting the end point and the above point, and repeats the same processing. If the distance from the straight line at the farthest point is equal to or less than the predetermined distance, the point sequence thinning unit 36 ends the point sequence thinning process. Thereby, the point sequence thinning unit 36 can create road shape data after thinning so that the difference from the original road shape in the base map data 2 is within a predetermined distance. The point sequence thinning unit 36 inputs the road shape data after the thinning to the lane expression changing unit 38.

  For example, FIG. 6A schematically illustrates a road section 116 before the point sequence thinning process is applied and a plurality of points 117a, 117b, 117c, and 117d that constitute the road section 116. . The point 117 a is the start point of the road section 116, and the point 117 b is the end point of the road section 116. FIG. 6B schematically illustrates the road section 116 after the point sequence thinning process is applied and a plurality of points 117a, 117b, and 117c constituting the road section 116. By thinning out the points 117d that have little influence on the expression of the road shape, the road section 116 is expressed by a smaller number of points than in FIG.

  FIG. 7 is an explanatory diagram of the curving process by the curving unit 37. The curving unit 37 reduces the capacity of the road shape data for each road section determined as a curved section by the shape determining unit 35. The curving unit 37 reduces the capacity of the road shape data by, for example, converting the road shape data into a Bezier curve. The curving unit 37 sets other points except the start point and the end point in the shape data of one section as control point candidates for the Bezier curve. The curving unit 37 temporarily performs a Bezier curve of the road shape data using each control point candidate as a control point, and calculates an error from the original road shape data. The curving unit 37 adopts, as a final control point, a control point candidate having the smallest error maximum value among all the control point candidates, and converts the road shape data into a Bezier curve. The curving unit 37 divides the road shape data at the midpoint of the road section when all of the calculated maximum error values are equal to or greater than a predetermined value (for example, 1 meter), and creates two road sections. The above curving process is re-executed for each road section. Thereby, the curving unit 37 can create the curved road shape data so that the difference from the original road shape in the base map data 2 is within a predetermined value. The curving unit 37 inputs the road shape data after curving to the lane expression changing unit 38. The road shape data may be a parametric curve other than a Bezier curve.

  For example, FIG. 7A schematically shows a road section 118 before the curving process is applied, and a plurality of points 119a, 119b, and 119c constituting the road section 118. The point 119 a is the start point of the road section 118, and the point 119 b is the end point of the road section 118. FIG. 6B schematically shows the road section 118 after the curving process is applied, and the Bezier curve start point 119a, end point 119b, and control point 120 that express the road section 118. By expressing the road shape with a parametric curve having two control points 120, the road section 118 is expressed with a smaller amount of data than in FIG.

  FIG. 8 is an explanatory diagram of the lane expression changing process by the lane expression changing unit 38. The lane expression changing unit 38 specifies a road section where the lanes are not increasing or decreasing in the section with respect to the road shape data input from the point sequence thinning unit 36 and the curving unit 37. The lane expression changing unit 38 changes the road shape data of each identified road section to a reference lane expression described below. For example, in the road section 121 shown in FIG. The lane expression changing unit 38 sets the leftmost lane 122 in the road section 121 as the reference lane of the road section 121. The lane expression changing unit 38 discards the road shape data expressing the lane 123 other than the reference lane, and adds the number of lanes and the lane width instead. As a result, as shown in FIG. 8B, the road section 121 is expressed with a smaller amount of data. That is, the reference lane expression is a road shape expression method using each data of the road shape of the reference lane, the number of lanes, and the lane width. Note that the lane expression changing unit 38 does not execute the above processing for road sections in which the number of lanes has increased or decreased within the section, and maintains road shape data for all lanes. The lane expression changing unit 38 outputs the road shape data after the above processing as the second shape data 41.

  FIG. 9 is a diagram illustrating a data structure of the second shape data 41. The second shape data 41 includes a plurality of road section data 130 representing one road section. Each road section data 130 includes expression type data 131, a curve / straight line flag 132, and shape data 133. The expression type data 131 is data indicating whether the road section is expressed by a reference lane expression or a normal expression that is not a reference lane expression. The curve / straight line flag is data indicating whether the road section is classified as a curved section or a straight section by the shape determination unit 35.

  The shape data 133 is data indicating a specific shape of the road section. The shape data 133 corresponding to the curve section of the reference lane expression includes the start point, the end point, and the control point of the parametric curve expressing the road shape for one lane. The shape data 133 corresponding to the straight section of the reference lane expression includes a plurality of points (including a start point and an end point) expressing the road shape for one lane. The shape data 133 corresponding to the curve section of the normal expression includes the start point, the end point, and the control point of the parametric curve expressing the road shape of each lane. The shape data 133 corresponding to the straight section of the normal expression includes a plurality of points (including a start point and an end point) that express the road shape of each lane.

  The data structure of the second shape data 41 illustrated in FIG. 9 is an example, and the second shape data 41 having a different data structure can be used. For example, the number of lanes and the lane width data may be omitted from the second shape data 41 for the road section expressed in the reference lane expression. In this case, the vehicle control device 6 using the vehicle control map data 4 acquires the lane number and lane width data not from the second shape data 41 but from the lane number data 42 and the lane width data 43.

  FIG. 10 is a flowchart of map data generation processing. In step S10, the shape determination unit 35 selects one unselected road section. In step S20, the shape determination unit 35 classifies the road section selected in step S10 into one of a straight section and a curved section. When it classify | categorizes into a linear area, the shape determination part 35 advances a process to step S30. In step S30, the point sequence thinning unit 36 executes a point sequence thinning process on the road sections classified as straight sections, and the process proceeds to step S50. If the road section is classified as a curved section in step S20, the shape determination unit 35 advances the process to step S40. In step S40, the curving unit 37 performs a curving process on the road section classified as the curve section, and advances the process to step S50.

  In step S50, the reference lane changing unit 38 determines whether the section selected in step S10 has a certain lane, in other words, for example, a road section where the lane is branched. If the lane is not converted in the road section, the reference lane changing unit 38 advances the process to step S60. In step S60, the reference lane changing unit 38 changes the road shape data subjected to the point sequence thinning process or the curving process to the reference lane expression.

  In step S70, the map data generation device 3 determines whether or not an unselected road section remains. If an unselected road section remains, the process proceeds to step S10. On the other hand, when all road sections have been selected, the map data generation process shown in FIG. 10 ends.

According to the embodiment described above, the following operational effects can be obtained.
(1) The shape determination unit 35 classifies roads whose road shapes are expressed by the first shape data 21 that expresses road shapes by a plurality of points 104 into straight sections and curved sections. The point sequence thinning unit 36 changes the road shape of the straight section to the expression by the first expression. The curving unit 37 changes the road shape of the curved section to an expression based on the second expression different from the first expression. The data output unit 332 outputs, as the second shape data 41, road shape data based on the expression changed by the point sequence thinning unit 36 and the curving unit 37. Since it did in this way, map data with little data amount which expressed the road shape optimally can be produced | generated.

(2) The lane expression changing unit 38 converts the road shape of the road including the plurality of lanes expressed in the first expression or the second expression into the road shape of at least one lane of the plurality of lanes and the lane of the plurality of lanes. Change to an expression that includes information about number and road width. Since it did in this way, the data amount of map data can be reduced more.

(3) When the one straight section and one curved section include a plurality of sections having different road attributes, the shape determination unit 35 treats each of the plurality of sections as a plurality of straight sections and a plurality of curved sections. Classify into: Since it did in this way, the data amount of map data can be reduced more.

(4) The first expression is an expression having a smaller data amount than the case where the road shape of the straight section is expressed by a plurality of points, and the second expression is more than the case where the road shape of the curved section is expressed by a plurality of points. Is an expression with a small amount of data. Since it did in this way, the data amount of map data can be reduced more.

(5) The first expression is an expression method for expressing the road shape of the straight section by a smaller number of points than the plurality of points included in the first shape data 21. The second expression is an expression method that expresses the road shape of a curved section by a parametric curve. The point sequence thinning unit 36 changes the expression of the road shape of the straight section to the first representation by the point sequence thinning process. The curving unit 37 changes the expression of the road shape of the curved section to the second expression by the curving process. Since it did in this way, each of a straight section and a curve section can be expressed with the optimal expression system.

(6) The point sequence thinning unit 36 is configured so that the difference between the road shape of the straight section in the first shape data 21 and the road shape of the straight section expressed by the first expression is within a predetermined amount. Pulling process. The curving unit 37 performs the curving process so that the difference between the road shape of the curved section in the first shape data 21 and the road shape of the curved section expressed by the second expression is within a predetermined amount. Since it did in this way, map data with desired accuracy and a small amount of data can be generated.

  The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.

(Modification 1)
Shape data different from the first shape data 21 illustrated in FIG. 4A may be handled. For example, each point 104a may include the altitude 103 as in the first shape data 21a illustrated in FIG. In this case, the point sequence thinning unit 36 and the curving unit 37 handle the road section in consideration of the altitude. For example, the point sequence thinning unit 36 connects the elevation of the start point and the elevation of the end point with a straight line in the shape data of one section, measures the elevation difference between the point farthest from the straight line and this straight line, When the difference exceeds a predetermined amount, the point is a point to be left after thinning. That is, the point sequence thinning unit 36 considers not only the planar distance but also the vertical distance so that the difference from the original road shape in the base map data 2 is within a predetermined value. It is determined whether the points are thinned out or left in later road shape data. The same applies to the curving unit 37.

  Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Vehicle control system, 2 ... Base map data, 3 ... Map data generation apparatus, 4 ... Map data for vehicle control, 5 ... Vehicle, 6 ... Vehicle control apparatus, 21 ... 1st shape data, 35 ... Shape determination part, 36: point sequence thinning unit, 37: curving unit, 38 ... lane expression changing unit, 41 ... second shape data

Claims (9)

A shape determination unit that classifies a road in which the road shape is expressed by first shape data that expresses the road shape by a plurality of points into a straight section and a curved section;
A point sequence thinning unit that changes the expression of the road shape of the straight section to the expression of the first expression;
A curving unit that changes the expression of the road shape of the curved section to an expression based on a second expression different from the first expression;
An output unit for outputting road shape data as the second shape data by the expression changed by the point sequence thinning unit and the curving unit;
A map data generation device comprising: The map data generation device according to claim 1,
Information on the road shape of a road including a plurality of lanes expressed by the first expression or the second expression, the road shape of at least one lane of the plurality of lanes, the number of lanes and the road width of the plurality of lanes A lane expression changing unit for changing to an expression including
The said output part is the map data generation apparatus which outputs the road shape data by the expression changed by the said lane expression change part as said 2nd shape data. The map data generation device according to claim 2,
In the case where one straight section or one curved section includes a plurality of sections having road attributes different from each other, the shape determining unit determines that each of the plurality of sections is a plurality of the straight sections or the plurality of the plurality of sections. Map data generation device that classifies into curve sections. In the map data generation device according to claim 3,
The first expression is an expression having a smaller data amount than the case where the road shape of the straight section is expressed by the plurality of points.
The map data generation device, wherein the second expression is an expression having a smaller amount of data than when the road shape of the curved section is expressed by the plurality of points. The map data generation device according to claim 4,
The first representation expresses the road shape of the straight section by a smaller number of points than the plurality of points,
The second representation expresses the road shape of the curved section by a parametric curve,
The point sequence thinning unit changes the road shape representation of the straight section to the first representation by a point sequence thinning process,
The curving unit is a map data generation device that changes a road shape expression of the curved section to the second expression by a curving process. In the map data generation device according to claim 5,
The point sequence thinning unit includes the point sequence so that a difference between a road shape of the straight section in the first shape data and a road shape of the straight section expressed by the first expression is within a predetermined amount. Thinning process,
The curving unit performs the curving process so that a difference between a road shape of the curved section in the first shape data and a road shape of the curved section expressed by the second expression is within a predetermined amount. Map data generator to perform. In the map data generation device according to claim 6,
The first shape data includes information on the altitude of the plurality of points,
The point sequence thinning unit is configured such that a difference between a road shape in the vertical direction of the straight section in the first shape data and a road shape in the vertical direction of the straight section expressed by the first expression is within a predetermined amount. The point sequence thinning process is performed so that
The curving unit is configured such that a difference between a road shape in the vertical direction of the curved section in the first shape data and a road shape in the vertical direction of the curved section expressed by the second expression is within a predetermined amount. A map data generation device that performs the curving process. A shape determination step of classifying a road in which a road shape is expressed by first shape data expressing a road shape by a plurality of points into a straight section and a curved section;
A point sequence thinning step for changing the expression of the road shape of the straight section to the expression of the first expression;
A curving step for changing the expression of the road shape of the curved section to an expression by a second expression different from the first expression;
An output step of outputting road shape data as the second shape data by the expression changed by the point sequence thinning step and the curving step;
A map data generation method comprising: A shape determination step for classifying the road in which the road shape is expressed by the first shape data expressing the road shape by a plurality of points into a straight section and a curved section;
A point sequence thinning step for changing the expression of the road shape of the straight section to the expression of the first expression;
A curving step for changing the expression of the road shape of the curved section to an expression by a second expression different from the first expression;
An output step of outputting road shape data as the second shape data by the expression changed by the point sequence thinning step and the curving step;
Map data generation program that causes a computer to execute.

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