Head-Up Display Projection for Sloped Road AR Alignment
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Solution Overview
Problem
Existing head-up displays (HUDs) struggle to accurately perform augmented reality (AR) display on road surfaces with slopes, as they rely on monocular cameras that introduce errors due to non-flat road surfaces, leading to inaccurate calculations and penetration of virtual images through the road surface.
Innovation Solution
The HUD system incorporates a LiDAR sensor to detect road surface information, calculates a virtual image plane position based on this data, and adjusts the display position to account for road surface slopes, using a virtual image optical system to project the image correctly along the road surface.
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 system structure remains simple, but measurement precision deteriorates on sloped road surfaces
Solution Approach 1:
The patent introduces road surface angle detection as an intermediary measurement that mediates between the monocular camera's 2D image data and the 3D spatial reconstruction. By detecting the road surface angle separately and using it to correct the vanishing point-based distance calculation, the system achieves accurate 3D positioning on sloped surfaces without requiring complex multi-camera systems. The road surface angle acts as a corrective intermediary that compensates for the inherent limitations of monocular vision.
2Device complexity
If virtual image display position is not adjusted for road surface slope, then the display system remains simple, but the virtual image penetrates through the road surface causing display inaccuracy
Solution Approach 1:
The patent applies preliminary action by pre-calculating the road surface angle and using it to adjust the virtual image display position before the actual AR display is rendered. The system proactively compensates for slope effects by modifying the projection parameters based on detected road geometry, ensuring that virtual images are correctly positioned along the road surface rather than penetrating through it. This preliminary adjustment prevents display errors rather than correcting them afterward.
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
This approach allows for accurate AR display on road surfaces with slopes, ensuring that virtual images are displayed correctly without penetrating the road surface, enhancing the HUD's functionality and accuracy.
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
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.