Method of automatically generating road network information and system for embodying the same

• US 5,848,375 A
• Filed: 04/19/1996
• Issued: 12/08/1998
• Est. Priority Date: 04/19/1995
• Status: Expired due to Fees

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Ito, Koichi, Yasuda, Tsuneo, Nunobiki, Tadashi, Wakabayashi, Kaoru
• Primary Examiner(s): Louis-Jacques, Jacques H.
• Application Number:
  US08/634,743
• Time in Patent Office: 963 Days
• Field of Search: 701/200, 701/202, 701/210, 701/211, 701/212, 701/208, 701/207, 701/209, 340/990, 340/995, 340/988, 340/911, 73/178 R
• US Class Current: 701/212
• CPC Class Codes: G01C 21/3815 Road data
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G09B 29/003 Maps

Abstract

Center lines, i.e., precise road network information may be extracted relative to road margin information in a large-scale map based on teaching road network information (first configuration). Then, center lines, i.e., detailed road network information may be extracted relative to narrow road margin segments whose respective road plane sides have not defined yet, on the basis of road margin segments whose respective road plane sides have already been defined (second configuration). Then, finished road network information may be extracted by correcting road network information derived from the second configuration (third configuration).

Claims

1. A method of automatically generating road network information, comprising the steps of:

a) extracting center lines relative to large-scale road margin information with employing small-scale road network information as teaching information;

b) extracting center lines relative to road margin information from which center lines have not extracted yet, based on road margin information from which center lines have already been extracted; and

c) interpolating center lines obtained in steps a) and b),

wherein said step a) comprises the steps of;

a1) converting said small-scale road network information and said large-scale road margin information on a same coordinate system;

a3) extracting sequentially center lines from concerned road segments in said large-scale road margin information relative to all road segments by selecting road segments from said small-scale road network information one by one; and

a4) passing information attached to said road network information as information attached to said center lines.

2. A method of automatically generating road network information according to claim 1, further comprising a step of a2) storing administrative number and attribute information of respective segments constituting said small scale road network information and said large-scale road margin information after said step a1).

3. A method of automatically generating road network information according to claim 1, wherein an administrative number and derived attribute information are stored every time when segment being as process object is processed in said step a3) and said step a4).

4. A method of automatically generating road network information according to claim 1, wherein said step a3) comprises the steps of:

a31) extracting, relative to said selected road segment, all road margin segments which are within a predetermined distance from said selected road segment and has more than predetermined parallelism to said selected road segment, from road margin segments in said road margin information,

a32) extracting intersecting points between horizontal or vertical scanning lines and all road margin segments extracted in said step a31) and setting respective middle points between a plurality of extracted intersecting points as road central point candidates,

a33) generating center line candidates by connecting road central point candidates being set in said step a32), and

a34) selecting a candidate which has most similar length, distance, and road width to those of said selected road segment from said center line candidates generated in said step a33), and determining the selected candidate as a center line relative to said selected road segment.

5. A method of automatically generating road network information according to claim 4, wherein, in said step a32), administrative numbers and attribute information of two referred road margin segments, road widths relating to these road margin segments, and administrative numbers of road segments in concerned road network information are affixed to respective road central point candidates.

6. A method of automatically generating road network information according to claim 4, wherein, in said step a33),

respective central point candidates are numbered in the order of array of said scanning lines and road central candidates on the same scanning lines are sequentially numbered, and

center line candidates are generated by connecting said road central point candidates, under conditions that said road margin segments on both sides which are used to extract said road central point candidates are identical, distances between said road central point candidates are within a predetermined distance, variation in road widths in excess of a predetermined value is not caused between adjacent road central point candidates, and a bending angle of each center line is less than a predetermined value.

7. A method of automatically generating road network information according to claim 4, wherein, in said step a34), such a candidate is selected from center line candidates as a center line that a length is close to that of said road segment, a distance away from said road segment is short, and a road width is close to that of said road segment.

8. A method of automatically generating road network information, comprising the steps of:

a) extracting center lines relative to large-scale road margin information with employing small-scale road network information as teaching information;

b) extracting center lines relative to road margin information from which center lines have not extracted yet, based on road margin information from which center lines have already been extracted; and

c) interpolating center lines obtained in steps a) and b),

wherein said step b) comprises the steps of;

b1) recognizing road plane side relative to road margin information from which a center line is extracted, based on information of said center line,

b2) recognizing road plane side relative to road margin information whose road plane is not defined, based on road margin information whose road plane side is defined in said step b1),

b3) recognizing paired road margin segments constituting road plane from road margin information of which road plane sides are newly defined in said step b2), and

b4) extracting a center line based on paired road margin segment defined in said step b3).

9. A method of automatically generating road network information according to claim 8, wherein, in said step b1) road margin information and center line information are received respectively from a road margin information storing means in which all said road margin information are stored and a center line information storing means in which center line information arc stored, and road margin information in which center lines are extracted are generated by correlating said road margin information with said center line information.

10. A method of automatically generating road network information according to claim 8, wherein said step b2) comprises the steps of:

b21) extracting road margin information whose road plane has not defined, and

b22) recognizing road plane side relative to extracted road margin information whose road plane has not defined.

11. A method of automatically generating road network information according to claim 10, wherein, in said step b21), road margin information whose road plane has not defined and which is adjacent to said road margin information whose road plane has been defined is extracted.

12. A method of automatically generating road network information according to claim 10, wherein, in said step b21), road margin information whose road plane has not def ined and which exists continuously near said road margin information whose road plane has been defined is extracted.

13. A method of automatically generating road network information according to claim 10, wherein, in said step b22), when road plane side is to be recognized relative to road margin information whose road plane has not defined, a connecting direction of road margin information whose road plane has not been def iced is so defined that road plane side thereof is on the same side as that of road margin information whose road plane has been defined.

14. A method of automatically generating road network information according to claim 8, wherein, in said step b4), entire center line information is generated by adding newly generated center line information to already generated center line information.

15. A method of automatically generating road network information according to claim 8, wherein, in said step b4), said center line is extracted by connecting middle points of extreme points on both ends in overlap portion of paired road margin segments recognized in said step b3).

16. A method of automatically generating road network information , comprising the steps of:

a) extracting center lines relative to large-scale road margin information with employing small-scale road network information as teaching information;

b) extracting center lines relative to road margin information from which center lines have not extracted yet, based on road margin information from which center lines have already been extracted; and

c) interpolating center lines obtained in steps a) and b),

wherein said step c) comprises the steps of;

c1) determining an extreme point of said center line extracted by up to said step b) as a dead end,

c2) connecting extreme points of two center lines by segment

c3) extracting intersecting points of center lines intersected,

c4) connecting a center line intersecting with prolonged line of another center line to a prolonged center line,

c5) connecting center lines at an intersecting point of prolonged lines of two center lines, and

c6) extracting extreme point nodes from all center line information.

17. A system for automatically generating road network information , comprising:

precise center line information generating means for extracting center lines relative to large-scale road margin information with employing small-scale road network information as teaching information;

detailed center line information generating means for extracting center lines relative to road margin information whose center lines have not been extracted, based on road margin information whose center lines have been extracted; and

finished center line information generating means for interpolating said center lines extracted by said detailed center line information generating means,

wherein said precise center line information generating means comprises,

coordinate transforming means for transforming said small-scale road network information and said large-scale road margin information to have the same coordinate system,

concerned center line extracting means for carrying out such processes relative to all road segments that road segments are selected from said small-scale road network information one by one and then center lines are extracted relative to said large-scale road margin information corresponding to said road segments, and

supplementary information succeeding means for succeeding to information affixed to said road network information as information affixed to said center lines.

18. A system for automatically generating road network information according to claim 17, further comprising storing means for storing administrative number and attribute information relative to respective segments constituting said small-scale road network information and said large-scale road margin information.

19. A system for automatically generating road network information according to claim 17, wherein administrative number and attribute information are stored every time when segments being subjected to process are processed in said concerned center line extracting means and said supplementary information succeeding means.

20. A system for automatically generating road network information according to claim 17, wherein said concerned center line extracting means comprises,

segment calculating means for calculating, relative to said selected road segment, all road margin segments which are within a predetermined distance from said selected road segments and have more than predetermined parallelism to said selected road segments, from road margin segments in said road margin information,

central point candidate extracting means for extracting intersecting points between horizontal or vertical scanning lines and said all road margin segments calculated by said segment calculating means, and setting respective middle points between a plurality of extracted intersecting points as road central point candidates,

center line candidate generating means for generating center line candidates by connecting said road central point candidates set by said central point candidate extracting means, and

center line determining means for selecting a candidate whose length, distance, and road width are most similar to those of said selected road segments from center line candidates generated by said center line candidate generating means, and determining the selected candidate as a center line with respect to said selected road segment.

21. A system for automatically generating road network information according to claim 20, wherein, in said central point candidate extracting means, administrative numbers and attribute information of two referred road margin segments, road widths relating to said two referred road margin segments, and administrative numbers of road segments in concerned road network information are affixed to respective road central point candidates.

22. A system for automatically generating road network information according to claim 20, wherein, in said center line candidate generating means,

respective central point candidates are numbered in the order of array of said scanning lines and road central candidates on the same scanning lines are sequentially numbered, and

center line candidates are generated by connecting said road central point candidates, under conditions that said road margin segments on both sides which are used to extract said road central point candidates are identical, distances between said road central point candidates are within a predetermined distance, variation in road widths in excess of a predetermined value is not caused between adjacent road central point candidates, and a bending angle of each center line is less than a predetermined value.

23. A system for automatically generating road network information according to claim 20, wherein said center line determining means selects such a candidate from center line candidates as a center line that a length is close to that of said road segment, a distance away from said road segment is short, and a road width is close to that of said road segment.

24. A system for automatically generating road network information , comprising:

precise center line information generating means for extracting center lines relative to large-scale road margin information with employing small-scale road network information as teaching information;

detailed center line information generating means for extracting center lines relative to road margin information whose center lines have not been extracted, based on road margin information whose center lines have been extracted; and

finished center line information generating means for interpolating said center lines extracted by said detailed center line information generating means,

wherein said detailed center line information generating means comprises,

road plane recognition processing means for recognizing road plane side relative to road margin information from which a center line is extracted, based on information of said center line,

unrecognized road margin information road plane recognizing means for recognizing road plane side relative to road margin information whose road plane is not defined, based on road margin information whose road plane side is defined in said road plane recognition processing means,

paired road margin segment recognition processing means for recognizing paired road margin segments constituting road plane from road margin information of which road plane sides are newly defined in said unrecognized road margin information road plane recognizing means, and

center line extracting means for extracting a center line based on paired road margin segment defined in said paired road margin segment recognition processing means.

30. A system for automatically generating road network information according to claim 24, wherein said center line extracting means generates entire center line information by adding newly generated center line information to already generated center line information.

31. A system for automatically generating road network information according to claim 24, wherein said center line extracting means extracts said center line by connecting middle points of extreme points on both ends in overlap portion of paired road margin segments recognized in said paired road margin segment recognition processing means.

26. A system for automatically generating road network information according to claim 26, wherein said unrecognized road margin information road plane recognizing means comprises,

unrecognized road margin information extracting means for extracting road margin information whose road plane has not defined, and

road plane recognizing means for recognizing road plane side relative to extracted road margin information whose road plane has not defined.

25. A system for automatically generating road network information according to claim 26, wherein said road plane recognition processing means receives respectively road margin information and center line information from a road margin information storing means in which all road margin information are stored and a center line information storing means in which center line information are stored, and generates road margin information in which center lines are extracted by correlating said road margin information with said center line information.

27. A system for automatically generating road network information according to claim 26, wherein said unrecognized road margin information extracting means extracts road margin information whose road plane has not defined and which is adjacent to said road margin information whose road plane has been defined.

28. A system for automatically generating road network information according to claim 26, wherein said unrecognized road margin information extracting means extracts road margin information whose road plane has not defined and which exists continuously near said road margin information whose road plane has been defined.

29. A system for automatically generating road network information according to claim 26, wherein said road plane recognizing means defines a connecting direction of road margin information whose road plane has not been defined such that road plane side thereof is on the same side as that of road margin information whose road plane has been defined, when road plane side is to be recognized relative to road margin information whose road plane has not defined.

32. A system for automatically generating road network information , comprising:

precise center line information generating means for extracting center lines relative to large-scale road margin information with employing small-scale road network information as teaching information;

detailed center line information generating means for extracting center lines relative to road margin information whose center lines have not been extracted, based on road margin information whose center lines have been extracted; and

finished center line information generating means for interpolating said center lines extracted by said detailed center line information generating means,

wherein said finished center line information generating means comprises,

means for determining an extreme point of said center line extracted by said detailed center line information generating means as a dead end,

means for connecting extreme points of two center lines by segments,

means for extracting intersecting points of center lines intersected,

means for connecting a center line intersecting with prolonged line of another center line to a prolonged center line,

means for connecting center lines at an intersecting point of prolonged lines of two center lines, and

means for extracting extreme point nodes from all center line information.

33. A method of automatically generating road network information, comprising the steps of:

a1) converting small-scale road network information and large-scale road margin information on a same coordinate system;

a3) extracting sequentially center lines from concerned road segments in said large-scale road margin information relative to all road segments by selecting road segments from said small-scale road network information one by one; and

a4) passing information attached to said road network information as information attached to said center lines.

34. A method of automatically generating road network information according to claim 33, further comprising a step of a2) storing administrative number and attribute information of respective segments constituting said small scale road network information and said large-scale road margin information after said step a1.

35. A method of automatically generating road network information according to claim 33, wherein an administrative number and derived attribute information are stored every time when segment being as process object is processed in said step a3) and said step a4).

36. A method of automatically generating road network information according to claim 33, wherein said step a3) comprises the steps of:

a31) extracting, relative to said selected road segment, all road margin segments which are within a predetermined distance from said selected road segment and has more than predetermined parallelism to said selected road segment, from road margin segments in said road margin information,

a32) extracting intersecting points between horizontal or vertical scanning lines and said all road margin segments extracted in said step a31), and setting respective middle points between a plurality of extracted intersecting points as road central point candidates,

a33) generating center line candidates by connecting road central point candidates being set in said step a32), and

a34) selecting a candidate which has most similar length, distance, and road width to those of said selected road segment from said center line candidates generated in said step a33), and determining the selected candidate as a center line relative to said selected road segment.

37. A system for automatically generating road network information, comprising:

coordinate transforming means for transforming a small-scale road network information and a large-scale road margin information to have the same coordinate system,

concerned center line extracting means for carrying out such processes relative to all road segments that road segments are selected from said small-scale road network information one by one and then center lines are extracted relative to said large-scale road margin information corresponding to said road segments, and

supplementary information succeeding means for succeeding to information affixed to said road network information as information affixed to said center lines.

38. A method of automatically generating road network information, comprising the steps of:

b1) recognizing road plane side relative to road margin information from which a center line is extracted, based on information of said center line,

b2) recognizing road plane side relative to road margin information whose road plane is not defined, based on road margin information whose road plane side is defined in said step b1),

b3) recognizing paired road margin segments constituting road plane from road margin information of which road plane sides are newly defined in said step b2), and

b4) extracting a center line based on paired road margin segment defined in said step b3).

39. A method of automatically generating road network information according to claim 38, wherein, in said step b1) road margin information and center line information are received respectively from a road margin information storing means in which all said road margin information are stored and a center line information storing means in which center line information are stored, and road margin information in which center lines are extracted are generated by correlating said road margin information with said center line information, and then road plane sides are recognized relative to road margin information having corresponding center line information.

40. A method of automatically generating road network information according to claim 38, wherein, in said step b1) said road margin information is displayed on displaying means, and an operator designates road plane side to said road margin information displayed on said displaying means via instructing means.

41. A method of automatically generating road network information according to claim 38, wherein said step b2) comprises the steps of:

b21) extracting road margin information whose road plane has not defined, and

b22) recognizing road plane side relative to extracted road margin information whose road plane has not defined.

42. A method of automatically generating road network information according to claim 38, wherein, in said step b4) entire center line information is generated by adding newly generated center line information to already generated center line information.

43. A method of automatically generating road network information according to claims 38, wherein, in said step b4), said center line is extracted by connecting middle points of extreme points on both ends in overlap portion of paired road margin segments recognized in said step b3).

44. A system for automatically generating road network information, comprising:

road plane recognition processing means for recognizing road plane side relative to road margin information from which a center line is extracted, based on information of said center line,

unrecognized road margin information road plane recognizing means for recognizing road plane side relative to road margin information whose road plane is not defined, based on road margin information whose road plane side is defined in said road plane recognition processing means,

paired road margin segment recognition processing means for recognizing paired road margin segments constituting road plane from road margin information of which road plane sides are newly defined in said unrecognized road margin information road plane recognizing means, and

center line extracting means for extracting a center line based on paired road margin segment defined in said paired road margin segment recognition processing means.