Camera Calibration via Dynamic Height Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing camera calibration methods for driver assistance systems in vehicles assume a constant mounting height, which is not applicable to trucks due to varying configurations and dynamic changes in mounting height caused by air suspension and loading, leading to reduced performance or malfunction of these systems.
Innovation Solution
A method that determines the actual mounting height of an image acquisition device by projecting a defined section of the roadway into the image plane, identifying objects at specific positions, calculating the route length, and adjusting the initial mounting height value based on the comparison of defined and calculated route lengths, using inverse perspective mapping and autocorrelation to ensure robustness and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a constant mounting height is assumed for calibration, then the calibration process is simplified and can be performed with fixed parameters, but the calibration becomes inaccurate for vehicles with varying mounting heights such as trucks
Solution Approach 1:
The patent changes the calibration approach from using fixed parameters to dynamically determining mounting height through image processing. The system processes captured images to calculate the actual mounting height by analyzing the position of the vehicle in the image and applying geometric relationships, thereby adapting the calibration parameters to match the actual vehicle configuration.
2Measurement precision
If additional sensors are used to measure the mounting height directly, then the mounting height can be determined accurately, but the system complexity and cost increase significantly
Solution Approach 1:
The patent replaces mechanical sensing devices with an image processing-based computational approach. Instead of using physical sensors to measure mounting height, the system uses a camera to capture images and processes these images through geometric calculations to determine the mounting height, thereby eliminating the need for additional mechanical measurement devices.
Solution Approach 2:
The patent introduces image processing as an intermediary between the camera and the calibration result. The image processing system acts as a mediator that extracts geometric information from captured images and transforms it into mounting height measurements, enabling indirect measurement without direct physical contact or additional sensors.
3Device complexity
If the mounting height is estimated based on vanishing point position, then the calibration can be performed without additional sensors, but the method cannot provide information about the actual mounting height
Solution Approach 1:
The patent extends the calibration approach by incorporating the vertical dimension (mounting height) into the image processing analysis. By analyzing the geometric relationships in the captured images and applying perspective projection principles, the system retrieves three-dimensional mounting height information from two-dimensional image data, thereby recovering lost dimensional information.
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 method allows for precise and stable calibration of camera systems across a wide range of mounting heights, enabling reliable operation in both passenger vehicles and trucks by isolating the effect of camera orientation and accounting for dynamic changes in mounting height.
Implementation Method 1
The measurement section is projected into the image plane of the image acquisition device by means of a perspective projection
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In a method for calibrating an image acquisition device mounted at a specific height on a motor vehicle, a preliminary value for the mounting height is assumed, and a measuring section with a defined length is defined in the road plane. Using perspective projection and the preliminary mounting height value, the measuring section is projected onto the image plane to determine measurement positions in the image that correspond to the beginning and end of the measuring section. An image processing system identifies an object in successively acquired images that is located at two measurement positions at different times. The calculated length of the measuring section is then determined from the time difference between these different times and the speed of the motor vehicle.By comparing the defined path length with the calculated path length, an actual mounting height value is determined from the preliminary value. The image acquisition device is then calibrated using this actual mounting height value.