Map data generating device, terminal device and map data generating method

Abstract

A map data generating device (1) for generating map data representing a three-dimensional shape by compressing three-dimensional shape information data using an approximate line, the map data generating device comprising: a three-dimensional point sequence information storage part (21) which stores data of a shape point sequence indicating the three-dimensional shape, wherein a sequence of a plurality of points arranged on an outline of the three-dimensional shape is used as the shape point sequence; a data conversion part (22) which acquires the shape point sequence from the three-dimensional point sequence information storage part (21); an approach division point extraction part (23) that generates an arc (31) passing through three object points and determines, based on the arc, whether an approach division point that should not be approximated in the three-dimensional shape is included in the three object points; an approximation processing part (24), wherein the approximation processing part (24) generates an approximate line that approximates the three-dimensional shape in the map data based on the acquired shape point sequence if the approximate division point extraction part (23) determines that the approximate division point is not included in the three object points, and wherein the approximation processing part (24) divides the shape point sequence acquired by the data conversion part (22) by the approximate division point and generates the approximate line that approximates the three-dimensional shape in the map data based on the divided shape point sequence if the approximate division point extraction part (23) determines that the approximate division point is included in the three object points; and an approach line parameter storage part (25) which stores parameters of the approach line; where the three object points are three points whose order in the shape point sequence is continuous, wherein the approach subdivision point extraction part (23) finds an index that indicates a difference (Da, Db) between - a line segment (La, Lb) connecting the center point and another point of the three object points in the shape point sequence, and - a part of the arc (31a, 31b) connecting the center point and the further point, and determining that an approach subdivision point is included in the three object points when the index is greater than a predetermined threshold.

Description

TECHNICAL FIELD

[0001] The present invention relates to a map data generating device capable of generating map data, and a method thereof, and a terminal device related to the map data. BACKGROUND

[0002] In recent years, map data capable of representing three-dimensional shapes of a road surface, a building, and equipment around a road, etc., through a three-dimensional point group have been proposed. The three-dimensional point group can be acquired from a real object using a combination of monitoring functions such as a GNSS (Global Navigation Satellite System) device, a laser radar, a camera, and the like. Since the acquired data volume of three-dimensional point group information is very large as it is, only necessary information is extracted.For example, in a map used in vehicle equipment, since three-dimensional positions and three-dimensional shapes of a center position of a road, a center position of each lane, a compartment lane, a character, and the like are useful, these pieces of information are extracted as three-dimensional shape information.

[0003] However, since the amount of three-dimensional shape information data tends to be large, not only a technique for adequately extracting the three-dimensional shape information but also a technique for compressing the three-dimensional shape information has been required. As such a technique, a technique for compressing the amount of three-dimensional shape information data by representing a three-dimensional shape using an approximate line has been proposed.

[0004] For example, in Patent Document 1, as data of a three-dimensional traveling locus detected by a position sensor during road travel, data of a plane traveling locus is generated using a horizontal orientation. Based on the plane traveling locus data, a control point, an arc related to the control point, and a relaxation curve associated with the arc are sequentially generated to be stored in a storage medium or the like. This makes it possible to represent a smooth center line corresponding to a center line of a three-dimensional road based on the generated arc, the relaxation curve, and the like. State of the art documentPatent document

[0005] Patent Document 1: Japanese Patent Laid-Open No. 2010-266306 SUMMARYProblem to be solved by the invention

[0006] However, in the conventional technique, in the process of deriving the approximate line, only an error between a point in a point sequence indicating the three-dimensional shape and the approximate line is evaluated, and an error at a point other than the relevant one is not considered. Therefore, according to the conventional technique, there has been a problem that an angular shape that would not be smooth in the three-dimensional shape would be represented by a smooth approximate line, so that a difference between the three-dimensional shape represented by the map data and a real three-dimensional shape becomes relatively large.For example, since shapes of a road edge and a fence base often include an angular shape compared with a shape of a road center line according to the conventional technique, there has been a problem that the shapes of the road edge and the fence base represented by the map data deviate relatively greatly from the real shapes.

[0007] From BRADLEY, C.: Numerically Controlled Machining From Three Dimensional Machine Vision Data. PhD Dissertation, University of Victoria, Department of Mechanical Engineering, 1992, 168 pages, it is known to divide a tool path defined by a series of surface data points into a sequence of arcs and lines. To do this, a circular arc is placed over the first, middle, and last data points in the series. The error between the intermediate data points and the arc is then determined. If the determined error for a given intermediate point exceeds a permissible maximum value, the given intermediate point becomes a new end point, and a new arc is placed over the starting point, a new center point, and the new end point.

[0008] An optimization approach for biarc curve-fitting of B-spline curves is described in ONG, CJ [et al.]: A optimization approach for biarc curve-fitting of B-spline curves. Computer-Aided Design, Vol. 28, 1996, pp. 951-959.

[0009] The present invention has been made in light of the above problem, and it is an object of the present invention to provide a technique capable of reducing a difference between a three-dimensional shape represented by map data using approximation and a three-dimensional shape of a real object. Means of solving the problem

[0010] This object of the present invention is achieved according to the invention as set forth in claims 1 and 12. Embodiments of the present invention emerge from the subclaims. Effects of the invention

[0011] According to the present invention, it is determined whether the approximate division point that should not be approximated in the three-dimensional shape is included in the three object points. This makes it possible to reduce the difference between the three-dimensional shape represented by the map data using the approximation and the real three-dimensional shape.

[0012] The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing a configuration of a map data generating device according to a first embodiment. Fig. 2 is a block diagram showing a configuration of a map data generating device according to a second embodiment. Fig. 3 is a flowchart showing the operation of the map data generating device according to the second embodiment. Fig. 4 is a diagram for describing the operation of an approach division point extraction part according to the second embodiment. Fig. 5 is a diagram for describing the operation of the approach division point extraction part according to the second embodiment. Fig. 6 is a flowchart showing the operation of the approach division point extraction part according to the second embodiment. Fig. 7 is a flowchart showing the operation of an approach division point extraction part according to a third embodiment. Fig. 8 is a flowchart showing the operation of an approach division point extraction part according to a fourth embodiment. Fig. 9 is a diagram for describing the operation of the approach division point extraction part according to the fourth embodiment. Fig. 10 is a flowchart showing the operation of an approach division point extraction part according to a fifth embodiment. Fig. 11 is a flowchart showing the operation of an approach division point extraction part according to a sixth embodiment. Fig. 12 is a diagram showing the operation of an approach division point extraction part according to a seventh embodiment. Fig. 13 is a diagram showing the operation of an approach division point extraction part according to the seventh embodiment. Fig. 14 is a diagram showing the operation of an approach division point extraction part according to the seventh embodiment. Fig. 15 is a block diagram showing a configuration of a car navigation device according to an eighth embodiment. Fig. 16 is a block diagram showing a configuration of a car navigation device according to a modification of the eighth embodiment. Fig. 17 is a block diagram showing a hardware configuration of a map data generating device according to another modification. Fig. 18 is a block diagram showing a hardware configuration of a map data generating device according to another modification. DESCRIPTION OF EMBODIMENTS<Erste Ausführungsform>

[0013] A map data generating device according to a first embodiment of the present invention is a device capable of generating map data, and the map data includes map data representing a three-dimensional shape using approximation.

[0014] Fig. 1 is a block diagram showing a configuration of a map data generating device 1 according to the first embodiment of the present invention. The map data generating device 1 in Fig. 1 includes a detection part 11 and a control part 12.

[0015] The acquisition part 11 acquires a shape point sequence, which is a point sequence indicating a three-dimensional shape. For example, a sequence of a plurality of points arranged on an outline of the three-dimensional shape or the like is used as the shape point sequence. The acquisition part 11 may acquire the shape point sequence from a device external to or internal to the map data generation device 1, or the acquisition part 11 may generate the shape point sequence based on other information.

[0016] The control part 12 decides three object points from the shape point sequence detected by the detection part 11. The three object points are any of three points whose order in the shape point sequence is continuous and three points whose order in the shape point sequence is N every time, where N is a natural number.

[0017] The control section 12 generates an arc that passes through the three object points based on the three object points. Since a circle contains an arc, even in a configuration where a circle is generated instead of an arc, an arc is consequently generated.

[0018] Based on the generated arc, the control section 12 determines whether an approach subdivision point that should not be approximated in the three-dimensional shape is included among the three object points. The approach subdivision point may also be called an approach subdivision position.

[0019] According to the map data generation device 1 according to the first embodiment, as described above, it is determined whether the approximate division point that should not be approximated in the three-dimensional shape is included in the three object points. This makes it possible to suppress the representation of an angular shape of the three-dimensional shape by a smooth approximate line, so that it is possible to reduce a difference between the three-dimensional shape represented by the map data using the approximation and the real three-dimensional shape. <Zweite Ausführungsform>

[0020] Fig. 2 is a block diagram showing a configuration of the map data generating device 1 according to a second embodiment of the present invention. Hereinafter, among the components described in the present second embodiment, the same reference numerals are assigned to components that are the same as or similar to those of the first embodiment, and different components will be mainly described.

[0021] The map data generating device 1 in Fig. 2 includes a three-dimensional point sequence information storage part 21, a data conversion part 22, an approximate division point extraction part 23, an approximate processing part 24, and an approximate line parameter storage part 25. The data conversion part 22 corresponds to the detection part 11 in Fig. 1 described in the first embodiment. The approximate division point extraction part 23 and the approximate processing part 24 correspond to the control part 12 in the first embodiment. Fig. 1. Each of the components of the Fig. 2 is described in detail below. <Dreidimensionaler Punktsequenz-Informationsspeicherteil 21>

[0022] The three-dimensional point sequence information storage part 21 stores data of a shape point sequence indicating a three-dimensional shape, a route, a structure, and the like, as three-dimensional point sequence information. In the following description, a route and a structure or the like as an object of data compression processing may be described as an "object shape." While the following description assumes that the object shape is a roadside, it is not limited to this. For example, the object shape may be a lane centerline shape, a structure such as a fence, a center of a road, a virtual line, a compartment lane, a line indicating a position of a three-dimensional structure, or the like. <Datenumwandlungsteil 22>

[0023] The data conversion part 22 acquires the three-dimensional point sequence information of the object shape from the three-dimensional point sequence information storage part 21. Based on the acquired three-dimensional point sequence information, the data conversion part 22 converts three-dimensional space coordinates into two-dimensional plane coordinates obtained by removing a one-dimensional coordinate component from the three-dimensional ROM coordinates. The data conversion part 22 retains the two-dimensional plane coordinates and stores information corresponding to the removed one-dimensional coordinate component in a storage part or the like (not shown). For example, as described in Japanese Patent Application No.According to the technique described in Patent Application Publication No. 2016-076357, when the data conversion part 22 is configured to convert the three-dimensional information into the two-dimensional information obtained by removing a height component from the three-dimensional information, the data conversion part 22 retains the two-dimensional information and also retains gradient data corresponding to the height component in the storage part (not shown) or the like. The data conversion part 22 outputs the two-dimensional shape point sequence obtained by the above-described conversion to the approximate division point extraction part 23.

[0024] However, depending on an implementation form, the data conversion part 22 may output the three-dimensional point sequence information acquired from the three-dimensional point sequence information storage part 21 to the approximate division point extraction part 23 as described above, without performing the above-described conversion. In the above-described configuration, the three-dimensional shape point sequence is output from the data conversion part 22 to the approximate division point extraction part 23. If the above-described conversion and its inverse conversion are appropriately performed, two dimensions and three dimensions can be handled substantially identically, so the two dimensions and three dimensions are substantially the same in the following description. <Annäherungs-Unterteilungspunkt-Extraktionsteil 23>

[0025] The approach division point extraction part 23 generates the arc and determines the approach division point for the three object points in the shape point sequence acquired by the acquisition part 11. Specific operations of the approach division point extraction part 23 will be described in detail later using a flowchart. <Annäherungsverarbeitungsteil 24>

[0026] If the approximate division point extraction part 23 determines that the approximate division point is not included in the three object points, the approximate processing part 24 generates an approximate line that approximates the three-dimensional shape based on all the shape point sequences acquired by the data conversion part 22.

[0027] On the other hand, if the approximate division point extraction part 23 determines that the approximate division point is included in the three object points, the approximate processing part 24 divides the shape point sequence acquired by the data conversion part 22 by the approximate division point and generates an appropriate line approximating the three-dimensional shape in the map data based on the divided shape point sequence.

[0028] For example, if the approximate division point extraction part 23 determines that there is an approximate division point between a start point and an end point of the shape point sequence, the approximate processing part 24 generates a first approximate line based on the start point, the approximate division point, and points therebetween, and generates a second approximate line based on the end point, the approximate division point, and points therebetween.

[0029] Further, for example, if the approximate division point extraction part 23 determines that there are two or more approximate division points between the start point and the end point of the shape point sequence, the approximate processing part 24 generates the first approximate line and the second approximate line similarly to the case described above, and generates a third approximate line based on two adjacent approximate division points and points therebetween.

[0030] For example, a general approximation such as the least squares method is used to generate an approximate line. As an approximate expression representing the approximate line, a function expression used for general approximation, such as a polynomial including a monic polynomial, is used. Each approximate line may be a line obtained by connecting a plurality of partial lines represented by a plurality of approximate expressions that are different from each other. <Annäherungslinienparameter-Speicherteil 25>

[0031] The approach line parameter storage part 25 stores parameters of the approach line generated by the approach processing part 24. The parameters of the approach line include, for example, coordinate information of an edge point of the approach line, parameters of the approximate expression representing the approach line, and the like. <betrieb>

[0032] Fig. 3 is a flowchart showing the operation of the map data generating device 1 according to the present second embodiment.

[0033] In step S1, the data conversion part 22 examines the three-dimensional point sequence information stored in the three-dimensional point sequence information storage part 21 and determines whether all the object shapes to be approximated have been approximated. If it is determined that they have not all been approximated, the processing proceeds to step S2, and if it is determined that all of them have been approximated, the processing ends in Fig. 3.

[0034] In step S2, the data conversion part 22 acquires an unapproximated object shape from the three-dimensional point sequence information storage part 21 and appropriately performs the above-described dimensional conversion for the object shape. At the end of step S2, the data conversion part 22 acquires a shape point sequence.

[0035] In step S3, the approximate division point extraction part 23 determines whether there is an approximate division point in the shape point sequence acquired in step S2.

[0036] In step S4, the approximation processing part 24 generates an approximation line of the object shape based on a determination result in S3. That is, the approximation processing part 24 derives the approximation line.

[0037] In step S5, the approximate line parameter storage section 25 stores the parameters of the approximate line generated in step S4. After that, processing returns to step S1. By executing steps S1 to S5 once, an approximation of an object shape to be approximated is performed, and steps S1 to S5 are repeated, approximating all object shapes to be approximated. <Betrieb von Annäherungs-Unterteilungspunkt-Extraktionsteil 23>

[0038] Fig. 4 and Fig. 5 are diagrams for describing the operation of the approach division point extraction part 23 according to the present second embodiment, that is, the operation in step S3 in Fig. 3. The following describes a case where the three object points are three points whose order in the shape point sequence is continuous.

[0039] In Fig. 4 are the three object points in the shape point sequence of the object shape a point P i (x i , y i ), P i+1 (x i+1 ; y i+1 ) and a point P i+2 (x i+2 , y i+2 ) shown. In this case, as shown in Fig. 4, the approach division point extraction part 23 generates an arc 31 passing the three object points.

[0040] Next, the approach division point extraction part 23 finds an index that represents a difference between a line segment La passing the center P i+1 and the other point P i which indicates three object points, and a partial arc 31a of the arc 31 corresponding to the line segment La. In the present second embodiment, the partial arc 31a corresponding to the line segment La is a region on an La side of regions obtained by dividing the arc 31 by the center point P i+1 be determined. Further, in the present second embodiment, the approximate division point extraction part 23 finds a distance Da between a predetermined point on the line segment La and the partial arc 31a as the above-described index.

[0041] Similarly, the approach division point extraction part 23 finds a distance Db between a predetermined point on a line segment Lb and a partial arc 31b as an index representing a difference between the line segment Lb including the center point P i+1 and the other point P i+2 connecting three object points, and indicating a partial arc 31b of the arc 31 corresponding to the line segment Lb.

[0042] The approach division point extraction part 23 determines that the approach division point is included in the three object points when the larger of the distances Da, Db is greater than a predetermined threshold. When it is determined that the approach division point is included in the three object points, the approach division point extraction part 23 according to the present second embodiment determines that the approach division point is the center point P. i+1 of the three object points.

[0043] The approach division point extraction part 23 performs the arc generation and the determination of the approach division point as described above while changing the three object points. In this case, as shown in Fig. 5, the approach division point extraction part 23 first decides three points 32a including the start point in the shape point sequence as the three object points, and performs the above-described arc generation and approximate division point determination for the three points 32a. Next, the approach division point extraction part 23 decides three points 32b obtained by sequentially shifting from the three points 32a to the end point side in the shape point sequence as the three object points, and performs the above-described arc generation and approximate division determination for the three points 32b. By repeating the above-described change of the three object points, the approach division point extraction part 23 performs the arc generation and approximate division point determination for all points in the shape point sequence.However, the three points initially used as three object points and the order thereof are not limited to the above.

[0044] Fig. 6 is a flowchart showing the operation of the approach division point extraction part 23 according to the present second embodiment.

[0045] In step S11, the approach division point extraction part 23 initializes the points P i , P i+1 , P i+2 , which are the three object points, with i = 0. However, in the case of 1 origin, which starts counting a number of suffix i from 1, instead of 0 origin, which starts counting the number of suffix i from 0, the three object points are initialized with i = 1. In the following description, the 0 origin is substituted, and the case where the initialization is performed with i = 0 is described.

[0046] In step S12, the approach division point extraction part 23 derives a circle corresponding to the points P i , P i+1 , P i+2 passing arc. Here, the approximate subdivision point extraction part sequentially substitutes 23 coordinates of the three points into the following expression (1), which is a general expression of a circle, acquires a 3-element simultaneous equation (j = i, i + 1, i + 2) with respect to 1, m, n, and solves the 3-element simultaneous equations, thereby deriving the circle. [Expression 1] xj2+I×xj+yj2+m×yj+n=0

[0047] In step S13, the approach division point extraction part 23 finds the distance DA between the predetermined point on the line segment La which includes the center point P i+1 and the other point P i connecting three object points and the partial arc 31a. Next, a case where the predetermined point is a center point of the line segment La will be described as an example. In this case, the distance Da is a length of a curvature of the partial arc 31a.

[0048] As a preliminary step to find Da, which is the length of the curvature of the partial arc 31a with respect to the coordinates P i , P i+1 is, the approach subdivision point extraction part 23 sets the coordinates P i , P i+1 of the points into the following expression (2) to find a half length Ba of the line segment La and substitute 1, m, n found in step S12 into the following expression (3) to find a radius r of the circle. [Expression 2] Ba=(xi−xi+1)2+(yi−yi+1)22 [Expression 3] r=I2+m24−n

[0049] Then, the approach division point extraction part 23 substitutes the found length Ba and the found radius r of the circle into the following expression (4) to find the distance Da, which is the length of the curvature of the partial arc 31a. [Expression 4] Da=r−r2−Ba2

[0050] Similar to the distance Da, the approach division point extraction part 23 finds the distance Db, which is the length of the curvature of the partial arc 31b.

[0051] In step S14, the approach division point extraction part 23 determines whether the larger of the distances Dr, Db found in step S13 is greater than the predetermined threshold. If the approach division point extraction part 23 determines that the distance is greater than the threshold, the processing proceeds to step S15, and if the approach division point extraction part 23 determines that the distance is equal to or less than the threshold, the processing proceeds to step S16. The approach division point extraction part 23 may determine whether a sum of the distances Dr and Db (= Da + Db) is greater than a threshold, instead of determining whether the larger of the distances Da, Db is greater than the threshold.

[0052] In step S15, the approach division point extraction part 23 stores the center point P i+1 as the approximate division point, for example, in a storage device such as a cache memory (not shown). Thereafter, processing proceeds to step S16.

[0053] In step S16, the approximate division point extraction part 23 determines whether the three object points include the end point of the shape point sequence or not, that is, whether or not i = M-2. Note that M is the total number of points in the shape point sequence. If i = M-2, it is determined that the generation of the arcs and the determination of the approximate division points have been performed for all points of the shape point sequence, and the processing in Fig. 6 ends. If i < M-2 instead of i = M-2, it is determined that the generation of arcs and the determination of approximate division points have not yet been performed for all points of the shape point sequence, and the processing proceeds to step S17.

[0054] In step S17, the approximate division point extraction part 23 increments i, and the processing returns to step S12.

[0055] The above described case is where three points whose order in the shape point sequence is continuous are used as the three object points. On the other hand, in the case of using three points whose order in the shape point sequence is each N as the three object points, a point P can be used in the above description. i+N+1 (x i+N+1 , y i+N+1 ) and a point P i+2N+2 (x i+2N+2 , y i+2N+2 ) instead of point P i+1 (x i+1 , y i+1 ) and the point P i+2 (x i+2 , y i+2 ) be used. <Geist der zweiten Ausführungsform>

[0056] According to the above-described map data generating device 1 according to the present second embodiment, in the second embodiment, it is determined whether or not the approach division point which should not be approximated in the three-dimensional shape is included in the three object points, so that it is possible to obtain similar effects to those of the first embodiment.

[0057] Furthermore, in the present second embodiment, if the distance between the line segment and the partial arc is greater than the threshold, it is determined that the approximate division point is included in the three object points. As a result, it is possible to extract the appropriate approximate division point from the shape point sequence.

[0058] In the present second embodiment, the shape point sequence acquired by the data conversion part 22 is divided by the approximate division point, and an approximate line approximating the three-dimensional shape in the map data is generated based on the divided shape point sequence. According to the configuration described above, it is unnecessary to perform recursive approximation processing in the approximation processing part 24, so the processing load can be reduced.

[0059] Furthermore, in the present second embodiment, by repeating the modification of the three object points, the generation of arcs and the determination of the approximate division points are performed for all points of the shape point sequence. This makes it possible to suppress errors in the extraction of the approximate division points. <Dritte Ausführungsform>

[0060] A block configuration of the map data generating device 1 according to a third embodiment of the present invention is the same as the block configuration described in the second embodiment in Fig. 2. Hereinafter, of components described in the present third embodiment, the same reference numerals are given to components which are the same as or similar to those of the second embodiment, and different components are mainly described.

[0061] In the second embodiment described above, the approximate division point extraction part 23 generates the arcs and determines the approximate division points for all points of the shape point sequence. In contrast, in the present third embodiment, the approximate division point extraction part 23 uses three points designated from outside the map data generation device 1 as the three object points in the shape point sequence. As the outside of the map data generation device 1, a user, a communication device that transmits a user's operation result, or the like are assumed.

[0062] Fig. Fig. 7 is a flowchart showing the operation of the approach division point extraction part 23 according to the present third embodiment. The operation in Fig. 7 is similar to the operation which from the changing step S11 to step S11a and deleting steps S16 and S17, the operation of Fig. 6. Here, in step S11, the three points designated from the outside are decided as the three object points. <Geist der dritten Ausführungsform>

[0063] According to the map data generation device 1 according to the present third embodiment, when there is an area that is desired to be evaluated in advance in three-dimensional form, it is possible to make a determination only for that area. Therefore, it is possible to shorten the time for extracting the approach division point. <Vierte Ausführungsform>

[0064] A block configuration of the map data generating device 1 according to a fourth embodiment of the present invention is the same as the block configuration in the map data generating device 1 described in the second embodiment. Fig. 2. Hereinafter, among components described in the present fourth embodiment, the same reference numerals are given to components which are the same as or similar to those of the second embodiment, and different components are mainly described.

[0065] In the second embodiment described above, as shown in Fig. 4, the distance Da between the predetermined point on the line segment La and the partial arc 31a is used as the index indicating the difference between the line segment La and the partial arc 31a. In contrast, in the present fourth embodiment, a range of a region surrounded by the line segment La and the partial arc 31a is used as the index indicating the difference between the line segment La and the partial arc 31a.

[0066] Fig. Fig. 8 is a flowchart showing the operation of the approach division point extraction part 23 according to the present fourth embodiment. The operation in Fig. 8 is similar to the operation resulting from changing steps S13 and S14 to steps S13b and S14b in the operation of Fig. 6. Therefore, steps S13b and S14b are mainly described below.

[0067] In step S13b, similar to step S13 in Fig. 6, the approach subdivision point extraction part 23 finds the half length Ba of the line segment La, the radius r of the circle and the distance Da which is the length of the curvature of the partial arc 31 in Fig. 9. By substituting these into the following expression (5), the approach division point extraction part 23 finds an area Sa of the region surrounded by the line segment La and the partial arc 31a, that is, a region on a lower line side of a hatched region in Fig. 9. [Expression 5] Sa=r2sin−1Bar−Ba×(r−Da)

[0068] Similar to the area Sa, the approach division point extraction part 23 finds an area Sb of a region formed by the line segment Lb and the partial arc 31b in Fig. 9, that is, a region on an upper right side of a hatched region in Fig. 9.

[0069] In step S14b, the approximate division point extraction part 23 determines whether a sum (= Sa + Sb) of the areas Sa, Sb found in step S13b is greater than a predetermined threshold. If it is determined that the sum of the areas is greater than the threshold, the processing proceeds to step S15, and if it is determined that the sum of the areas is equal to or less than the threshold, the processing proceeds to step S16. Note that, instead of determining whether the sum (= Sa + Sb) of the areas Sa, Sb is greater than the threshold, the approximate division point extraction part 23 may determine whether the area of ​​the larger one of the areas Sa, Sb is greater than the threshold. <Geist vierter Ausführungsform>

[0070] According to the above-described map data generating device 1 according to the present fourth embodiment, when the area of ​​the region surrounded by the line segment and the partial arc is larger than the threshold value, it is determined that the approximate division point is included in the three object points. As a result, it is possible to extract the appropriate approximate division point from the shape point sequence. <Fünfte Ausführungsform>

[0071] A block configuration of the map data generating device 1 according to a fifth embodiment of the present invention is the same as the block configuration of Fig. 2 described in the second embodiment. Hereinafter, among the components described in the present fifth embodiment, the same reference numerals are assigned to components that are the same as or similar to those of the second embodiment, and different components will be mainly described.

[0072] In the second embodiment described above, when the index indicating the difference between the line segment and the partial arc is greater than the predetermined threshold, the approximate division point extraction part 23 determines that the approximate division point is included in the three object points. In contrast, in the present fifth embodiment, the approximate division point extraction part 23 generates a first arc using the first three points in the shape point sequence as the three object points. The approximate division point extraction part 23 generates a second arc using second three points obtained by shifting sequentially from the first three points in the shape point sequence as these three object points.When a difference between a curvature of the first arc and a curvature of the second arc is larger than a predetermined threshold, the approach division point extraction part 23 determines that the approach division point is included in a point overlapping between the first three points and the second three points.

[0073] Fig. Fig. 10 is a flowchart showing the operation of the approach division point extraction part 23 according to the fifth embodiment. The operation in Fig. 10 is similar to the operation consisting of steps S12 to S15 to steps S12c to S15c in the operation in Fig. 6 results. Therefore, steps S12c to S15c are mainly described below.

[0074] In step S12c, the approach division point extraction part 23 derives a first circle corresponding to the first arc including the first points P i , P i+1 , P i+2 as in step S12 of Fig. 6. Further, the approach subdivision point extraction part 23 derives a second circle corresponding to the second points P i+1 , P i+2 , P i+3 , as in step S12 of Fig. 6 passing second arch.

[0075] In step S13c, similar to S13 in Fig. 6, the approximate division point extraction part 23 finds the radius r of the first circle and a radius ra of the second circle. The approximate division point extraction part 23 finds a curvature R (= 1 / r) of the first circle from the radius of the first circle and finds a curvature Ra (= 1 / ra) of the second circle from the radius ra of the second circle.

[0076] In step S14c, the approximate division point extraction part 23 determines whether a difference (= |R - Ral) between the curvature R of the first circle and the curvature Ra of the second circle is greater than a predetermined threshold. If it is determined that the difference is greater than the threshold, the process proceeds to step S15c, and if it is determined that the difference is equal to or less than the threshold, the process proceeds to step S16.

[0077] In step S15c, the approach dividing point extraction part 23 stores as the approach dividing point that lies between the first points P i , P i+1 , P i+2 , and the second point P i , P i+2 , P i+3 , overlapping P i+2 in a storage device such as a cache memory (not shown) or the like. Subsequently, the processing proceeds to step S16. <Geist fünfter Ausführungsform>

[0078] According to the above-described map data generating device 1 of the present fifth embodiment, when the difference between the curvature of the first arc and the curvature of the second arc is greater than the predetermined threshold, it is determined that the approximate division point is included in the point overlapping between the first three points and the second three points. As a result, it is possible to extract the appropriate approximate division point from the shape point sequence.

[0079] In the above description, the three second points are the points P i , P i+1 , P i+2 , P i+3 , which are determined by moving the first three points in a direction in which the subscript becomes larger. However, the present invention is not limited to this, and the second three points may be the three points P i-1 , P i , P i+1 which are determined by moving the first three points in a direction in which the subscript becomes smaller. The approach subdivision point extraction part 23 can determine the radius rb of the three points P i-1 , P i , P i+1 passing second circle and find a curvature rb (= 1 / rb) of the second circle to determine whether a difference (= |R - Rb|) between the curvature R of the first circle and the curvature Rb of the second circle is greater than a predetermined threshold.

[0080] Alternatively, the approach division point extraction part 23 may extract the curvature Ra of the three points P i , P i+1 , P i+2 passing second circle and the curvature Rb of the three points P i-1 , P i , P i+1 passing other second circle. The approach division point extraction part 23 may determine whether a larger of the difference (= |R - Ra|) between the curvature R of the first circle and the curvature Ra of the one second circle and the difference (= |R - Rb|) between the curvature R of the first circle and the curvature Rb of the other second circle is greater than a predetermined threshold. <Sechste Ausführungsform>

[0081] A block configuration of the map data generating device 1 according to a sixth embodiment of the present invention is the same as the block configuration of Fig. 2 described in the second embodiment. Hereinafter, among the components described in the present sixth embodiment, the same reference numerals are assigned to components that are the same as or similar to those of the second embodiment, and different components will be mainly described.

[0082] In the sixth embodiment, the approach division point extraction part 23 determines that the approach division point is included in the three object points when a curvature of an arc passing the three object points is larger than a predetermined threshold.

[0083] Fig. Fig. 11 is a flowchart showing the operation of the approach division point extraction part 23 according to the present sixth embodiment. The operation in Fig. 1 is similar to the operation consisting of change steps S13 and S14 to steps S13d and S14d in the operation of Fig. 6. Therefore, steps S13d and S14d are mainly described below.

[0084] In step S13d, similar to step S13 in Fig. 6, the approach subdivision point extraction part 23 finds the radius r of the circle and finds the curvature R (= 1 / r) of the circle from the found radius r of the circle.

[0085] In step S14d, the approximate division point extraction part 23 determines whether the curvature R of the circle is greater than the predetermined threshold. If it is determined that the curvature R is greater than the threshold, the processing proceeds to step S15, and if it is determined that the difference is equal to or less than the threshold, the processing proceeds to step S16. <Geist der sechsten Ausführungsform>

[0086] According to the above-described map data generating device 1 according to the present sixth embodiment, when the curvature of the arc passing through the three object points is greater than the predetermined resistance value, it is determined that the approaching division point is included in the three object points. As a result, it is possible to extract the appropriate approaching division point from the shape point sequence. <Siebte Ausführungsform>

[0087] A block configuration of the map data generating device 1 according to a sixth embodiment of the present invention is the same as the block configuration of the map data generating device 1 described in the second embodiment. Fig. 2. Hereinafter, among the components described in the present sixth embodiment, the same reference numerals are given to components that are the same as or similar to those of the second embodiment, and different components therefrom are mainly described.

[0088] In the second embodiment described above, while the three object points are sequentially changed from the start point to the end point of the shape point sequence acquired by the data conversion part 22, the approach division point extraction part 23 performs the generation of the arc and the determination of the approach division point, and the determination result of the approach division point is used as it is.

[0089] In contrast, in the present seventh embodiment, the approximate division point extraction part 23 performs first processing including arc generation and approximate division point determination while sequentially changing the three object points from the start point, which is one edge point of the shape point sequence acquired by the data conversion part 22, to the end point, which is the other edge point. Furthermore, the approximate division point extraction part 23 performs second processing including arc generation and approximate division point determination while sequentially changing the three object points from the end point to the start point of the shape point sequence acquired by the data conversion part 22.Then, when it is determined that the first point is not an approach division point in at least one of the first processing and the second processing, the approach division point extraction part 23 determines that the first point is not the approach division point as a result of the first processing and the second processing.

[0090] For example, as in Fig. As shown in Figure 12, assume that while the three object points are sequentially changed from a start point P1 to an end point P5 of the shape point sequence, the approach division point extraction part 23 has performed the first processing including arc generation and determination of the approach division point, and has determined that a point P4 is the approach division point. In this case, the map data generation device 1 according to the second embodiment generates an approach line AL1 based on the points P1 to P4 and generates a straight line (not shown) connecting the points P4 and P5.

[0091] In contrast, the approach division point extraction part 23 according to the present seventh embodiment performs not only the first processing but also the second processing including the generation of the arc and the determination of the approach division point while sequentially changing the three object points from the end point P5 to the start point P1 of the shape point sequence, as shown in Fig. 13. Even if the approach division point extraction part 23 determines that the point P4 is the approach division point in the first processing, it is determined that the point P4 is not the approach division point in the second processing, the approach division point extraction part 23 determines that the point P4 is not the approach division point as a result of the first processing and the second processing. In this case, the map data generation device 1 according to the seventh embodiment generates an approach line AL2 based on the points P1 to P5. As a result, the map data generation device 1 according to the present seventh embodiment can reduce the number of approach lines compared with the second embodiment, so that the compressibility of the data can be improved.

[0092] As a configuration in which the determination result differs between the first processing and the second processing, for example, a configuration or the like can be considered where, in the configuration of finding the distance Da between the predetermined point on the line segment La which has the center P i+1 and the other point P i the three object points in Fig. 4, and the partial arc 31a, a position of the predetermined point differs between the first processing and the second processing. In addition, it is predicted that the determination results of the first processing and the second processing may differ depending on the design of the determination as to whether the approach division point is included in the three object points based on the arc. <Geist der siebten Ausführungsform>

[0093] According to the above-described map data generating device 1 according to the present seventh embodiment, when it is determined that the first point is not the approximate division point in at least one of the first processing and the second processing, it is determined that the first point is not the approximate division point as a result of the first processing and the second processing. As a result, since the number of approximate lines can be reduced, the compressibility of data can be improved.

[0094] In addition, it is possible to improve the compressibility of data to some extent in a case where an approximate line obtained by combining two curves is used, compared with a case of using an approximate line obtained by combining a curve and a straight line. Therefore, when it is determined in the first processing that the first point is the approximate division point, and when it is determined in the second processing that the first point is not the approximate processing point, the approximate division point extraction part 23 can determine that a second point obtained by shifting 1 from the first point to the start point side is the approximate division point.

[0095] For example, in Fig. 12, if it is determined in the first processing that the point P4 is the approach division point, and it is determined in the second processing that the point P4 is not the approach division point, the point P3 obtained by shifting the point P4 by one point to the starting point P1 is determined as the approach division point. In this case, as in Fig. As shown in Figure 14, the map data generating device 1 generates an approximate line AL1' based on the points P1 to P3 and generates an approximate line AL2' based on the points P3 to P5. According to the above-described configuration, a probability of using an approximate line obtained by combining two curves is higher than that of using an approximate line obtained by combining a curve and a straight line, so that the compressibility of data can be improved.

[0096] In the seventh embodiment described above, it is determined whether three-point approach is possible on the end point P5 side, but this is not limited to it, and the number of points to be approached on the end point P5 side may be three or more. Furthermore, in the seventh embodiment described above, the first processing and the second processing may be interchanged. That is, the first processing may be the processing that includes creating the arc and determining the approach division point while changing the three object points from the end point P5 to the start point P1 of the shape point sequence, and the second processing may be the processing that includes creating an arc and determining the approach division point while sequentially changing the three object points from the start point P1 to the end point P5 of the shape point sequence. <Achte Ausführungsform>

[0097] As each of the map data generating devices 1 according to the first to seventh embodiments, for example, a device used by a map data vendor or the like is assumed. In this case, the map data generated by the map data generating device 1 is stored in the storage device included in a terminal device, and the terminal device can represent the three-dimensional shape using the map data.

[0098] For example, a vehicle terminal, a portable terminal, or the like is used as the terminal device. For example, a PND (Portable Navigation Device), a car navigation device, or the like is used as the vehicle terminal device. For example, a communication terminal such as a mobile phone, a smartphone, a tablet, or the like is used as the portable terminal device.

[0099] Fig. 15 is a block diagram showing a configuration of a car navigation device 71, which is a terminal device. The car navigation device 71 in Fig. 15 includes an output part 72, a map generation part 73, a storage part 74 and a control part 75 which controls them collectively, and is connected to the display device 76.

[0100] The storage part 74 stores the map data including the approach line parameters generated by the map data generation device 1. The control part 75 reads the map data from the storage part 74 as needed to output it to the map generation part 73, and the map generation part 73 generates a map in which the three-dimensional shape can be represented based on the map data including the approach line parameters. The control part 75 outputs the map generated by the map generation part 73 to the display device 76 via the output part 72, and the display device 76 displays the map. In the car navigation device 71 configured as described above, it is possible to display this three-dimensional shape in which a difference from a real three-dimensional shape is suppressed. <Modifikation achter Ausführungsform>

[0101] In the eighth embodiment, the map data generation device 1 is assumed to be a device used by a map data distributor or the like, but is not limited thereto. For example, the map data generation device 1 may be included in a terminal device such as a car navigation device 71.

[0102] Specifically, a car navigation device 71 as shown in Fig. 16, is conceivable. The car navigation device 71 in Fig. 16 includes a communication part 77 in addition to the components in Fig. 15.

[0103] The communication part 77 communicates with an exterior of the car navigation device 71, thereby acquiring the shape point sequence indicating the three-dimensional shape. The control part 75 generates the arc passing through the three object points based on the three object points in the shape point sequence acquired by the communication part 77, and determines whether the approach division point is included in the three object points based on the arc. The control part 75 generates the approach line that approximates the three-dimensional shape based on the determination result and stores the parameters of the approach line in the storage part 74. Even with the car navigation device 71 configured in this way, it was possible to display the three-dimensional shape in which the difference from the real three-dimensional shape is suppressed.It should be noted that this is not limited to the car navigation device 71, but the same applies to a terminal device other than the car navigation device.

[0104] Furthermore, the map data generation device 1 described above can also be applied to a map data generation system constructed as a system by appropriately combining a navigation device, a communication terminal including a portable terminal such as a mobile phone, a smartphone, a tablet, or the like, functions of applications to be installed in the above, and a server. In this case, the respective functions and components of each of the map data generation devices described above can be arranged to be distributed to each of the devices constructing the system, or can be arranged to be concentrated in any one of the devices. <Andere Modifikationen>

[0105] The detection part 11 and the control part 12 in the above-described map data generating device 1 are hereinafter referred to as a "detection part 11 and the like". The detection part 11 and the like are realized by a processing circuit 81 as shown in Fig. 17. That is, the processing circuit 81 includes the detection part 11 that detects the shape point sequence indicating the three-dimensional shape, and the control part 12 that generates the arc passing through the three object points based on the three object points in the shape point sequence detected by the detection part 11, and determines whether the approaching division point that should not be approximated in the three-dimensional shape is included in the three object points based on the arc. Dedicated hardware may be applied to the processing circuit 81, or a processor that executes a program stored in the memory may be applied. The processor corresponds to, for example, a central processing unit, a processing device, an arithmetic operation device, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), or the like.

[0106] In the case where the processing circuit 81 is dedicated hardware, the processing circuit 81 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The respective functions of the parts, such as the sensing part 11 and the like, may be realized by circuits in which the processing circuits are distributed, or may be realized by a processing circuit in which the respective functions of the parts are collected. When the processing circuit 81 is a processor, the functions of the sensing part 11 and the like are realized in combination with software and the like. The software and the like, for example, correspond to software, firmware, or software and firmware.Software and the like are described as a program and stored in memory. As in . Fig. As shown in Fig. 18, a processor 82 applied to the processing circuit 81 realizes the functions of the respective parts by reading and executing the program stored in the memory 83. That is, the map data generating device 1 uses the memory 83 to store the program, which thus executes a step of detecting the shape point sequence indicating the three-dimensional shape and a step of generating the arc passing the three object points and determining whether the approach division point that should not be approximated in the three-dimensional shape is included in the three object points based on the arc when the program is executed by the processing circuit 81. In other words, it can also be said that this program causes a computer to execute a procedure and method of the detecting part 11 and the like.Here, the memory 83 corresponds to any storage medium including a non-volatile or a volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory) or the like, a hydraulic pressure (hard disk drive), a magnetic disk, a flexible disk, an optical disk, a compact disc, a mini disk, a DVD (Digital Versatile Disc) and a drive device therefor, and the like.

[0107] In the above, the configuration in which the respective functions of the detection part 11 and the like are realized by hardware, software, and the like has been described. However, the present invention is not limited to this, and the configuration may be such that part of the detection part 11 and the like is realized by dedicated hardware and another part is realized by software and the like. For example, with regard to the detection part 11, its function may be realized by a processing circuit as dedicated hardware, such as a receiver, and with regard to the other, the processing circuit 81 as the processor 82 may read and execute the program stored in the memory 83 to realize its functions. As described above, the processing circuit 81 may realize the above-described functions by hardware, software, or the like, or a combination thereof.

[0108] It should be noted that, within the scope of the invention, the present invention can freely combine the embodiments and the modifications, and can modify and omit the embodiments and the modifications accordingly.

[0109] Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. It should be understood that countless modifications (not illustrated) may be conceived without departing from the scope of the present invention. EXPLANATION OF REFERENCE SYMBOLS 1 map data generation device 11 Recording part 12 Control unit 31 sheets 31a, 31b Partial arc 71 Car navigation device La, Lb line segment< / betrieb>

Claims

[1] A map data generating device (1) for generating map data representing a three-dimensional shape by compressing three-dimensional shape information data using an approximate line, the map data generating device comprising: a three-dimensional point sequence information storage part (21) which stores data of a shape point sequence indicating the three-dimensional shape, wherein a sequence of a plurality of points arranged on an outline of the three-dimensional shape is used as the shape point sequence; a data conversion part (22) which acquires the shape point sequence from the three-dimensional point sequence information storage part (21); an approach division point extraction part (23) that generates an arc (31) passing through three object points and determines, based on the arc, whether an approach division point that should not be approximated in the three-dimensional shape is included in the three object points; an approximation processing part (24), wherein the approximation processing part (24) generates an approximate line that approximates the three-dimensional shape in the map data based on the acquired shape point sequence if the approximate division point extraction part (23) determines that the approximate division point is not included in the three object points, and wherein the approximation processing part (24) divides the shape point sequence acquired by the data conversion part (22) by the approximate division point and generates the approximate line that approximates the three-dimensional shape in the map data based on the divided shape point sequence if the approximate division point extraction part (23) determines that the approximate division point is included in the three object points; and an approach line parameter storage part (25) which stores parameters of the approach line; where the three object points are three points whose order in the shape point sequence is continuous, wherein the approach subdivision point extraction part (23) finds an index that indicates a difference (Da, Db) between - a line segment (La, Lb) connecting the center point and another point of the three object points in the shape point sequence, and - a part of the arc (31a, 31b) connecting the center point and the further point, and determining that an approach subdivision point is included in the three object points when the index is greater than a predetermined threshold. [2] The map data generating device according to claim 1, wherein, by repeating the change of the three object points, the approach division point extraction part (23) performs the generation of the arc (31) and the determination of the approach division point for all points of the shape point sequence. [3] The map data generating device (1) according to claim 1, wherein the approach division point extraction part (23) uses three points designated from outside the map data generating device in the shape point sequence as the three object points. [4] The map data generating device (1) according to claim 1, wherein the approach division point extraction part (23) uses a distance between a predetermined point on the line segment (La, Lb) and the partial arc (31a, 31b) as the index. [5] The map data generating device (1) according to claim 1, wherein the approach division point extraction part (23) uses an area of ​​a region surrounded by the line segment (La, Lb) and the partial arcs (31a, 31b) as the index. [6] The map data generating device (1) according to claim 1, wherein the approximate division point extraction part (23) generates a first arc (31) using first three points in the shape point sequence as the three object points and further generates a second arc (31) using, as the three object points, second three points obtained by shifting one by one from the first three points in the shape point sequence, and determines that the approximate division point is included in a point overlapping between the first three points and the second three points when a difference between a curvature of the first arc and a curvature of the second arc is greater than a predetermined threshold. [7] The map data generating device (1) according to claim 1, wherein the approach division point extraction part (23) determines that the approach division point is included in the three object points when a curvature of the arc (31) is larger than a predetermined threshold. [8] The map data generating device (1) according to claim 1, wherein the approach division point extraction part (23) performs first processing including generation of the arc (AL1) and determination of the approach division point while sequentially switching the three object points from one edge point (P1) to the other edge point (P5) of the shape point sequence acquired by the data conversion part (22), and the second processing includes generation of the arc (AL2) and determination of the approach division point while sequentially switching the three object points from the other edge point (P5) to the one edge point (P1) of the shape point sequence acquired by the data conversion part (22), and determines that a first point (P4) is not the approach division point as a result of the first processing and the second processing when it is determinedthat the first point (P4) is not the approach division point in at least one of the first processing and the second processing., [9] The map data generating device (1) according to claim 8, wherein, when it is determined that the first point (P4) is the approach dividing point in the first processing and it is determined that the first point (P4) is not the approach dividing point in the second processing, the approach dividing point extraction part (23) determines that a second point (P3) obtained by shifting by one point from the first point (P4) to an edge point side is the approach dividing point. [10] Terminal equipment (71) capable of representing the three-dimensional shape using the map data generated by the map data generating equipment (1) according to claim 1. [11] A map data generating method for generating map data representing a three-dimensional shape by compressing three-dimensional shape information data using an approximate line, the method comprising: Storing data of a shape point sequence indicating the three-dimensional shape, wherein a sequence of a plurality of points arranged on an outline of the three-dimensional shape is used as the shape point sequence; Capturing the shape point sequence; Creating an arc (31) passing through three object points, and determining, based on the arc, whether an approach division point that should not be approximated in the three-dimensional shape is included in the three object points; Creating an approximate line that approximates the three-dimensional shape in the map data based on the acquired shape point sequence if it is determined that the approximate division point is not included in the three object points; Dividing the acquired shape point sequence by the approach division point and generating the approach line that approximates the three-dimensional shape in the map data based on the divided shape point sequence if it is determined that the approach division point is included in the three object points; and Saving approach line parameters; where the three object points are three points whose order in the shape point sequence is continuous; and Finding an index that indicates a difference (Da, Db) between - a line segment (La, Lb) connecting the center and another point of the three object points in the shape point sequence and - a part of the arc (31a, 31b) connecting the center point and the further point, and Determining that the approach division point is included in the three object points when the index is greater than a predetermined threshold.

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