Road Gradient Determination Using Spline Curve Fitting

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for determining road gradients using two-dimensional road lines and three-dimensional laser point cloud data suffer from reduced precision due to instability in horizontal coordinates, leading to inaccurate elevation information and road gradient calculations.

Innovation Solution

A method that forms a three-dimensional road line by selecting nodes from the two-dimensional road line and laser point cloud data, drawing a spline curve to indicate elevation, converting it into a gradient spline curve, and using location information to determine a road gradient, thereby avoiding horizontal errors and ensuring consistency and continuity of road gradient data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If two-dimensional road line and three-dimensional laser point cloud data are used to determine road gradient, then road gradient can be calculated, but precision is reduced due to horizontal coordinate instability

Engineering Contradiction:
Improveroad gradient precisionVSAvoidhorizontal coordinate stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent transitions from two-dimensional road line data to three-dimensional road line data by incorporating elevation information from laser point cloud data. This dimensional enhancement allows the system to calculate road gradient directly from vertical coordinates without relying on horizontal coordinate stability, thereby resolving the precision issue caused by horizontal coordinate instability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the coordinate parameters used for gradient calculation from horizontal coordinates to vertical coordinates. By using the vertical distance between adjacent nodes on the three-dimensional road line divided by the horizontal distance, the system eliminates the influence of horizontal coordinate instability on gradient precision while maintaining the necessary spatial relationships.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If three-dimensional road line with spline curve is used, then geometric continuity is ensured, but calculation complexity increases

Engineering Contradiction:
Improvegeometric continuityVSAvoidcalculation complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent applies spline curve fitting to the three-dimensional road line data in advance to establish a smooth, geometrically continuous representation of the road profile. This preliminary processing ensures that subsequent gradient calculations are based on continuous geometric data, while the complexity is managed by performing the fitting operation once during data preparation rather than repeatedly during gradient computation.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3757613B1Method and device for determining road gradient, storage medium, and computer device
Publication Date: 2023.07.19 TENCENT TECHNOLOGY (SHENZHEN) CO LTD
  • EP3757613B1 patent drawingFigure 1
  • EP3757613B1 patent drawingFigure 2
  • EP3757613B1 patent drawingFigure 3~5

AI summary

A method and device for determining a road gradient, a storage medium, and a computer device. The method comprises: acquiring a three-dimensional road line constituted by a two-dimensional road line and laser cloud point data of a road (S202); selecting multiple nodes on the three-dimensional road line as control points for a spline curve (S204); drawing on the basis of the control points a first spline curve used for expressing road elevation (S206); converting the first spline curve into a second spline curve used for expressing road gradient (S208); acquiring location information (S210); and determining a first road gradient on the basis of the location information and of the second spline curve (S212). This increases the precision of the road gradient.