Rearview Assembly Calibration Using Stationary Landmark Detection
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Solution Overview
Problem
Existing driver monitoring systems in vehicles face challenges in accurately determining the location and orientation of the driver after adjustments to the rearview assembly, necessitating expensive direct measurement methods.
Innovation Solution
A system comprising a rearview assembly with a barrel having moveable joints, an imager, processor, and a memory with CAD file information, which allows for calibration by identifying stationary landmarks and recalibrating based on their relative positions in captured images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If expensive direct measurement sensors are used to measure adjustments to the rearview assembly, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses image capture of stationary landmarks as a copy/representation of the physical space, replacing expensive direct measurement sensors. The imager captures images of known landmarks, and their positions in the images are used to calculate rearview assembly adjustments through coordinate transformations, achieving accurate measurement without physical sensors at the adjustment points.
Solution Approach 2:
The patent replaces mechanical measurement systems (physical sensors) with an optical/image-based system. Instead of using mechanical sensors to directly measure adjustment movements, the system uses an imager to capture images of stationary landmarks and processes these images computationally to determine adjustment positions and orientations.
2Device complexity
If image-based calibration methods are used to track rearview assembly adjustments, then device complexity is reduced, but measurement precision may be compromised
Solution Approach 1:
The system establishes a feedback loop where the imager continuously captures images of stationary landmarks, the controller processes these images to detect landmark position changes, calculates adjustment movements, and uses this information to recalibrate the driver monitoring system. This closed-loop feedback ensures measurement precision is maintained through iterative correction.
Solution Approach 2:
The patent performs preliminary calibration by capturing images of stationary landmarks when the rearview assembly is in a known initial position. The positions of landmarks in these preliminary images are stored and used as reference points for subsequent adjustment measurements, enabling accurate tracking of any deviations from the calibrated state.
3Reliability
If recalibration is performed frequently to maintain accuracy after adjustments, then monitoring accuracy is improved, but loss of time increases
Solution Approach 1:
The system implements periodic recalibration by continuously or periodically capturing images of stationary landmarks and automatically processing these images to detect adjustments. This periodic action ensures the driver monitoring system remains calibrated without requiring manual intervention, balancing accuracy maintenance with time efficiency through automated routine operations.
Data Source
AI summary
A system for calibrating a driver monitoring system in a vehicle comprises a rearview assembly comprising a housing, a mount secured to a vehicle surface, and a barrel extending between the housing and the mount; an imager disposed in the rearview assembly; a processor in communication with the imager; a memory comprising a file containing information on stationary landmarks proximate the imager; and a controller operable to: receive images of the vehicle's interior and calibrate the imager by identifying a substantially stationary landmark in a first image used during an initial calibration; wherein the controller is configured to re-calibrate the driver monitoring operations based, at least in part, on a detection of the substantially stationary landmark being in a different location in a second image relative to the first image. One of the ends of the barrel is connected with a moveable joint.