Head-Up Display Road-Slope Correction for Accurate AR Projection
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Solution Overview
Problem
Monocular cameras struggle to accurately calculate distances on non-flat road surfaces with slopes, leading to errors in augmented reality (AR) displays, as they include the height of the road surface in the calculation, making it difficult to perform AR displays along sloped road surfaces.
Innovation Solution
A head-up display (HUD) system that uses a road surface detection sensor to acquire information on the road surface, calculates a virtual image plane position, and adjusts the display position to account for the road surface slope, allowing for accurate AR display on sloped surfaces by using a virtual image optical system and a main controller to project the image light and control the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a monocular camera is used to estimate distance based on vanishing point height, then the calculation is simple, but the accuracy deteriorates on sloped road surfaces due to inclusion of road surface height in the calculation
Solution Approach 1:
The invention segments the road surface into multiple measurement points (first, second, and third measurement points) at different positions. By measuring the road surface shape at these discrete points and constructing a plane equation, the system separates the road surface height component from the distance calculation, thereby resolving the accuracy issue on sloped surfaces while maintaining computational feasibility.
2Ease of operation
If AR display is performed without considering road surface slope, then the display process is simple, but the virtual images appear to penetrate the road surface and misalignment occurs
Solution Approach 1:
The invention performs preliminary measurement of the road surface shape using multiple measurement points before generating the AR display. By constructing a plane equation from these measurements and calculating the intersection between the virtual image plane and road surface plane, the system prepares the correct display position in advance, ensuring accurate AR display that respects the actual road surface geometry.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate AR display on road surfaces with slopes by correcting for the road surface height, preventing virtual images from appearing to penetrate the surface and improving the alignment of AR elements with the real-world environment.
Implementation Method 1
a road surface detection sensor mounted on a vehicle with the head-up display and being positioned forward of a traveling direction of the vehicle
Implementation Method 2
a virtual image optical system configured to enlarge and project the image light
Implementation Method 3
irradiating an image light including a display object toward a projection target member so as to display the display object as a virtual image
Data Source
AI summary
A main controller of an HUD is configured to: acquire road surface information of a front road surface based on a plurality of measurement points on the front road surface, which is detected by a road surface detection sensor mounted on a vehicle with the HUD and is positioned forward of a traveling direction of the vehicle; calculate, by using the road surface information, a virtual image plane position on a virtual image plane where a virtual image of a display object is displayed, which is a display position of the virtual image for displaying the virtual image along the front road surface; and calculate a display position of a display surface within an image display device, which corresponds to the virtual image plane position, so as to output, to the image display device, a control signal for displaying the display object on the display position of the display surface.