Vehicle Camera Autocalibration via Cornering Maneuvers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current camera calibration methods for Advanced Driver Assistance Systems (ADAS) are costly, error-prone, and require precise target patterns, which are difficult to manufacture and maintain, especially with wide-angle and telephoto lenses, and are susceptible to environmental influences, necessitating frequent recalibration.
Innovation Solution
A method for autocalibration of a vehicle camera during travel using cornering maneuvers, where the camera detects stationary objects to reconstruct intrinsic and extrinsic parameters, eliminating the need for precise targets and allowing continuous improvement of calibration parameters, utilizing a bundle adjustment method with radial distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precise target patterns are used for camera calibration at the end of the production line, then calibration quality is improved, but manufacturing costs and complexity increase significantly
Solution Approach 1:
The camera system performs self-calibration during vehicle operation by automatically detecting stationary objects in the environment and using their apparent motion during cornering maneuvers to recalibrate intrinsic parameters, eliminating the need for manual recalibration and precise target patterns
Solution Approach 2:
The calibration process extracts useful information from ordinary environmental objects (stationary objects like buildings, trees, signs) rather than requiring specialized calibration targets, transforming everyday scene elements into calibration references
2Measurement precision
If calibration is performed at the end of the camera production line with precise targets, then initial calibration accuracy is improved, but the system becomes susceptible to environmental influences requiring frequent recalibration
Solution Approach 1:
The system continuously monitors the camera's performance during vehicle operation and automatically triggers recalibration when cornering maneuvers are detected, using feedback from the vehicle's motion and stationary object analysis to maintain calibration accuracy throughout the camera's lifetime
Solution Approach 2:
The calibration system transitions from a static initial calibration to a dynamic continuous recalibration process, adapting to environmental changes and system drift by performing updates whenever suitable cornering maneuvers occur during normal vehicle operation
3Adaptability or versatility
If wide-angle and telephoto lenses are used to expand detection range, then surveillance capability is improved, but calibration requirements become more stringent and costly
Solution Approach 1:
The system uses inexpensive, easily available stationary objects in the environment (buildings, trees, signs, road markings) as calibration references instead of expensive precision-manufactured target patterns, making calibration accessible for various lens types without stringent manufacturing requirements
4Length of stationary object
If the working range is extended to 6-100 m, then detection capability is improved, but the calibration area requirements become impractically large
Solution Approach 1:
The system utilizes the temporal dimension by performing calibration during dynamic cornering maneuvers, transforming a spatial problem (requiring large calibration areas) into a temporal solution where calibration occurs over time during natural vehicle operation, leveraging motion parallax from curved paths
Data Source
AI summary
A method for autocalibration of a (monocular) vehicle camera has the following steps:a) acquiring from the vehicle camera (1), a series of images of a region of the surroundings in front of the vehicle,b) detecting a cornering maneuver (25) of the vehicle suitable for autocalibration, when the curve radius (21) described by the vehicle is less than or equal to a maximum radius and the traversed curve angle (22) is greater than or equal to a minimum angle, andc) performing autocalibration, when at least one cornering maneuver (25) has been identified as suitable for autocalibration, wherein the autocalibration takes account of movement of stationary objects in the surroundings of the vehicle in the image sequence or sequences of one or more cornering maneuvers (25) suitable for autocalibration. An autocalibration apparatus is also provided.