Analytical Curve to Clothoid Conversion via Break-Point Segmentation
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Solution Overview
Problem
Current methods face challenges in converting analytical curve road geometry to clothoid road geometry efficiently and accurately for use in map displays and advanced driver assistance systems (ADAS).
Innovation Solution
A method is provided to determine break-point locations along an analytical curve based on its curvature profile, splitting the curve into sections and converting them into clothoids by using coordinates, tangent headings, or curvatures at start and end break-points, and approximating the curvature profile with polylines to define straight or multi-modal sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyline link geometry is used to represent road network, then the data structure is simple and easy to process, but it cannot provide accurate road geometry for clothoid-based ADAS capabilities and map displays
Solution Approach 1:
The patent transforms the road geometry representation from polyline format to clothoid format by changing the mathematical parameters used to describe the curve. This involves converting discrete line segments into continuous clothoid curves defined by mathematical functions, thereby improving geometric accuracy while maintaining computational tractability through parameter transformation.
Solution Approach 2:
The patent introduces an intermediate conversion process that acts as a mediator between the simple polyline representation and the required clothoid representation. This conversion methodology includes determining break-point locations, calculating clothoid parameters, and generating the transformed geometry, thus bridging the gap between simplicity and accuracy.
2Manufacturing precision
If complex conversion methods are used to transform analytical curve to clothoid geometry, then the accuracy of conversion is improved, but the computational complexity and processing time increase
Solution Approach 1:
The patent divides the analytical curve into multiple sections by determining break-point locations along the curve. Each section is then independently converted to a clothoid segment. This segmentation approach reduces the overall complexity by breaking down a complex global conversion problem into simpler local conversion problems that can be solved more efficiently.
Solution Approach 2:
The patent applies partial action by converting only the necessary portions of the analytical curve to clothoid geometry based on curvature profiles and break-point locations. Rather than converting the entire curve uniformly, the method selectively transforms sections where conversion is most beneficial, thereby reducing unnecessary computational effort while maintaining accuracy where needed.
3Ease of operation
If the entire analytical curve is converted to clothoid geometry at once, then the conversion is straightforward, but the computational load and processing time increase significantly
Solution Approach 1:
The patent segments the analytical curve into multiple smaller sections based on break-point locations determined from curvature profiles. Each segment is converted to clothoid geometry independently and in sequence, which reduces the computational burden on any single processing step and allows for more efficient utilization of computational resources over time.
Solution Approach 2:
The patent performs preliminary actions by first determining the curvature profile and identifying break-point locations before proceeding with the actual clothoid conversion. This preparatory step organizes the conversion process into manageable sections in advance, making the subsequent conversion operations more efficient and reducing overall processing time.
Data Source
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AI summary
A method, apparatus and computer program product are provided in order to convert a representation of a road geometry in the form of an analytical curve to a clothoid road geometry. In the context of a method, a plurality of break-point locations are determined along an analytical curve that represents a portion of the road network. The method determines the plurality of break-points locations by determining the plurality of break-point locations depending upon a curvature profile of the analytical curve so as to define one more sections of the analytical curve based upon the break-point locations. The method also converts one of more sections of the analytical curve to respective clothoids.