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"Technique for Generating from Point Data Geometric Data That Continuously Describe a Course of a Geographic Object" in Patent Application Approval Process

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This patent application has not been assigned to a company or institution.

The following quote was obtained by the news editors from the background information supplied by the inventors: "Modern navigation systems and other systems such as an Advanced Driver Assistance System (ADAS) rely on map data. Map data typically comprise point data indicative of geographic coordinates of certain geographic objects such as roads, railway lines, street addresses, rivers and special points of interest (such as hotels, restaurants and gas stations). For roads and other extended geographic objects discontinuous point data are not always a suitable base for the implementation of required processing or display functions. It has thus been proposed to represent the course of an extended geometric object by a continuous sequence of linear geometric elements such as circular arcs, line segments and clothoids.

"DE 101 14 412 C1 teaches a technique for converting road points into a sequence of clothoids that describe a continuous course of a road. DE 10 2005 024 558 A1 describes an approach for deciding for a set of two adjacent road points whether to select a line, a circular arc or a clothoid as the geometric element for locally describing the course of the road between these two road points. The information about the individual geometric elements thus determined is used for calculating a maximum vehicle speed per geometric element."

In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventors' summary information for this patent application: "There is a need for a mathematically robust and fast technique for generating from a set of point data geometric data that continuously describe a course of a geographic object.

"According to a first aspect, a method of generating from a point set geometric data that continuously describe a course of a geographic object is provided, wherein the method comprises determining, from sub-sets of two or more points, a sequence of two or more primary base elements, determining, for adjacent primary base elements, an interconnecting secondary base element that continuously connects to and at a connection point has the same gradient as each of the interconnected primary base elements, determining, for adjacent primary and secondary base elements, an interconnecting transition curve that continuously connects to and at a connection point has the same gradient and the same curvature as each of the interconnected primary and secondary base elements, and determining geometric data that continuously describe a course of the geographic object from the primary base elements, the secondary base element and the transition curve.

"The geographic object may be an extended geographic object described by two or more points. As an example, the geographic object may be a road, a railway line, a river, and so on. The points describing the geographic object may be provided in the form of geographic coordinates (e.g., as map data).

"The step of determining the interconnecting transition curve may comprise manipulating at least one of the adjacent primary and secondary base elements so as to realize a positional offset between the adjacent primary and secondary base elements at their connection point. The positional offset thus realized may be bridged by the interconnecting transition curve. The positional offset may be bridged in such a manner that the interconnecting transition curve continuously connects to and at a connection point has the same gradient and the same curvature as each of the interconnected primary and secondary base elements.

"The manipulating step may be performed in various ways. As an example, at least one of the adjacent primary and secondary base elements may be manipulated by the impression of a shift. The shift may be realized by a translatory movement. Additionally, or as an alternative, at least one of the adjacent primary and secondary base elements may be rotated so as to realize the positional offset. As a further alternative, or in addition, a radius of at least one of the adjacent primary and secondary base elements may be varied.

"The positional offset may be defined by at least one of a selected length of the transition curve, a length of the associated primary base element and a length of the associated secondary base element. As an example, a certain length of the transition curve may be selected in a first step and the positional offset may then be chosen such that the transition curve interconnecting the adjacent primary and secondary base elements can assume the selected length. The length of the transition curve may be selected statically or dynamically.

"In one implementation the length of the transition curve is dynamically selected dependent on a length of at least one of the interconnected primary and secondary base elements. In other implementations the length of the transition curve may be defined by a selected positional offset. Both implementations may be combined, for example by defining a maximum positional offset and selecting the length of the transition curve with the constraint that the maximum positional offset should not be exceeded.

"The transition curve may be selected from a transition curve set comprising a clothoid, a sine wave and a parabola, including any approximations thereof. Moreover, the primary and secondary base elements may be selected from a base element set comprising a line, a line segment, a circle and a circular arc, including any approximations thereof. As will be appreciated, a line segment may, for example, be approximated by a circular arc having a very large radius. In a similar manner, a circular arc may be approximated by a clothoid segment having an almost constant curvature, and so on.

"The primary base elements may be determined in various ways. As an example, determining the primary base elements may comprise interpolating the individual sub-sets of points. It should be noted that the size of an individual sub-set of points for determining an individual base element may statically be configured or may dynamically be determined. The interpolation process may comprise a least-square or any other metric-based process. The kind of primary base elements to be used may statically be configured (e.g., such that always circles or circular arcs are used) or may dynamically be selected. In a similar manner, also the kind of the secondary base elements interconnecting adjacent primary base elements may either statically be configured or dynamically be selected.

"The step of determining a primary base element may further comprise defining a corridor around an individual sub-set of points. The corridor may have a predefined width (of, e.g., 0.25 m to 3 m). Moreover, the corridor may, for example, be utilized in connection with dynamically determining a number of points from which an individual primary base element will be determined.

"The secondary base element interconnecting adjacent primary base elements may also be determined in numerous ways. As an example, determining the interconnecting secondary base element may comprise determining a point of intersection between the adjacent primary base elements. If such a point of intersection can be determined, the interconnecting secondary base element may be calculated based on the point of intersection thus determined.

"Also provided is a computer program product comprising program code portions for performing the steps of any method or method aspect presented herein when the computer program product is executed on a computing device (i.e., on a processor or a processor set). The computer program product may be stored on a computer readable recording medium, such as a hard disk, CD-ROM, DVD or semiconductor memory. Moreover, the computer program product may be provided for download via a network such as the Internet.

"Still further, a database with geometric data that continuously describe a course of a geographic object is provided, wherein the geometric data in the database have been generated in accordance with the method presented herein. The database may belong to an ADAS and may thus be installed on a vehicle. Alternatively, the database may be installed in or may be accessible by a navigation device. The navigation device may be portable or of the built-in type.

"Also provided is an apparatus for generating from a point set geometric data that continuously describe a course of a geographic object. The apparatus comprises a processor configured to determine, from sub-sets of two or more points, a sequence of primary base elements, to determine, for adjacent primary base elements, an interconnecting secondary base element that continuously connects to and at a connecting point has the same gradient as each of the interconnected primary base elements, to determine, for adjacent primary and secondary base elements, an interconnecting transition curve that continuously connects to and at a connection point has the same gradient and the same curvature as each of the interconnected primary and secondary base elements, and to determine geometric data that continuously describe a course of the geographic object from the primary base elements, the secondary base element and the transition curve.

"The apparatus may further comprise or have access to a database with point data for the purpose of determining the sequence of primary base elements by the processor. The point data may take the form of geographic coordinates (e.g., as acquired using mobile mapping and/or satellite-based systems such as the Global Positioning System, GPS, or the Galileo system).

BRIEF DESCRIPTION OF THE DRAWINGS

"Further aspects, details and advantages of the present disclosure will become apparent from the following description of exemplary embodiments in conjunction with the exemplary drawings, wherein:

"FIG. 1 illustrates an embodiment of an apparatus for generating geometric data that continuously describe a course of a road;

"FIG. 2 schematically illustrates an embodiment of a vehicle-based ADAS operating on the geometric data generated by the apparatus in FIG. 1;

"FIG. 3 shows a flow diagram illustrating a method embodiment of operating the apparatus of FIG. 1;

"FIG. 4 is a schematic diagram illustrating a sequence of interconnected road points;

"FIG. 5 is a schematic diagram illustrating the provision of a corridor for a set of interconnected road points;

"FIG. 6 is a schematic diagram illustrating a sequence of primary base elements for individual sub-sets of road points;

"FIG. 7 is a schematic diagram illustrating the processing of a primary base element;

"FIGS. 8A, 8B are schematic diagrams illustrating examples of the determination of a secondary base element from two adjacent primary base elements;

"FIG. 9 is a schematic diagram illustrating a sequence of primary and secondary base elements;

"FIG. 10 is a schematic diagram illustrating a curvature diagram for the sequence of primary or secondary base elements of FIG. 9;

"FIG. 11 is a schematic diagram illustrating the determination of an interconnecting transition curve for adjacent primary and secondary base elements;

"FIG. 12 is a schematic diagram illustrating a sequence of primary base elements, secondary base elements and transition curves; and

"FIG. 13 is a schematic diagram illustrating a curvature diagram for the sequence of primary base elements, secondary base elements and transition curves of FIG. 12."

URL and more information on this patent application, see: Grothe, Carsten; Stecher, Sandra; Labella, Thomas. Technique for Generating from Point Data Geometric Data That Continuously Describe a Course of a Geographic Object. Filed

Keywords for this news article include: Patents.

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