Map Height Rendering Using Relative Elevation Data
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Solution Overview
Problem
Existing map data processing technologies do not adequately ensure the confidentiality of real height data while providing accurate map display images, particularly in autonomous driving applications.
Innovation Solution
A method and apparatus for processing map data that determines relative height data using first reference points within a region, generating a map display image based on these data to keep real height data confidential, employing techniques such as polynomial equations and B-spline surfaces to calculate and display relative height information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If real height data is used directly for map display, then display accuracy is improved, but data security deteriorates
Solution Approach 1:
The patent extracts only the necessary relative height information from the real height data while removing the absolute height values. By calculating height differences between reference points and display points rather than using absolute heights, the system achieves display accuracy without exposing sensitive real height data, thus resolving the contradiction between display precision and data security.
Solution Approach 2:
The patent creates a virtual height data copy that mimics the structure and relative characteristics of real height data without containing the actual sensitive information. This virtual copy is generated through polynomial fitting and relative height calculations, providing sufficient display accuracy while maintaining data confidentiality, thereby resolving the contradiction between accurate display and security.
2Reliability
If virtual height data is generated to protect confidentiality, then data security is improved, but display smoothness deteriorates
Solution Approach 1:
The patent performs preliminary polynomial fitting using reference points before generating virtual height data for display points. This pre-calculation of fitting coefficients ensures that the generated virtual height data maintains smooth transitions and continuous surfaces, preventing display artifacts while preserving data security.
Solution Approach 2:
The patent transforms the height data representation from absolute height values to relative height differences, and uses polynomial order parameters to control the smoothness of the fitted surface. By adjusting polynomial parameters and using higher-order fits, the system maintains display smoothness while using virtual height data for security.
3Reliability
If polynomial fitting is used to generate virtual height data, then data security is improved, but computational complexity increases
Solution Approach 1:
The patent divides the map display area into multiple regions with reference points strategically distributed throughout. By segmenting the calculation domain and using local polynomial fitting rather than global fitting, the computational complexity is reduced while maintaining data security through virtual height generation.
Solution Approach 2:
The patent calculates polynomial fitting coefficients only at reference points rather than at every display point, then uses these coefficients to generate virtual height data for all display points through evaluation. This partial calculation approach significantly reduces computational complexity while maintaining data security and display quality.
Data Source
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AI summary
Aspects of the present invention are directed to a method for processing map data, including: determining a first region for which a map display image is to be drawn; determining multiple first reference points within the first region according to a second region corresponding to the first region; determining relative height data of the first region according to positions and real height data of all the first reference points; and determining a map display image of a position to be displayed according to the relative height data, in which the position to be displayed is within the first region.