Rearview Mirror Camera Orientation Tracking for Driver Gaze Accuracy
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Solution Overview
Problem
Existing vehicular driver monitoring systems face inaccuracies in determining driver gaze direction due to the movable nature of the interior rearview mirror, which complicates the positioning and orientation of the camera, leading to erroneous determinations of driver distraction.
Innovation Solution
A vehicular driver monitoring system utilizing a magnetic sensing device, such as a 3D hall effect sensor, to determine the orientation of the mirror head relative to the mounting structure, coupled with image processing to accurately track the camera's position and viewing angle, ensuring precise gaze direction analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the interior rearview mirror is made movable to allow driver adjustment of rearward view, then the ease of operation is improved, but the measurement precision of driver gaze direction deteriorates due to changing camera position and orientation
Solution Approach 1:
The system incorporates sensors that continuously detect the mirror head's position and orientation relative to the mounting structure. This feedback information is fed to the processor, which uses it to dynamically adjust the camera's field of view parameters and image processing algorithms, thereby compensating for mirror movement and maintaining accurate gaze direction measurement throughout the adjustment range.
Solution Approach 2:
The patent introduces an intermediary computational layer that acts as a mediator between the movable mirror/camera system and the gaze analysis function. The processor serves as this intermediary, transforming raw camera images into accurate gaze measurements by applying geometric corrections based on the mirror's detected position, thus isolating the measurement accuracy from the mechanical movement.
2Device complexity
If the camera is integrated into the movable mirror head, then the device complexity is reduced, but the measurement precision of driver monitoring deteriorates due to position variability
Solution Approach 1:
Position sensors mounted on the mounting structure detect the mirror head's location and orientation in real-time. This feedback is continuously provided to the processor, which uses it to calculate correction factors for the camera's viewing geometry, ensuring that gaze direction measurements remain accurate despite the camera's movement with the mirror head.
Solution Approach 2:
The system transitions from a static camera mounting approach to a dynamic adaptation approach. The processor dynamically adjusts the image processing parameters and geometric models based on the real-time position of the camera, allowing the integrated movable system to maintain measurement precision equivalent to a fixed camera system.
3Productivity
If image processing is performed based on fixed camera position assumptions, then the processing speed is improved, but the measurement precision deteriorates due to mirror movement
Solution Approach 1:
The system performs preliminary detection of the mirror head's position and orientation using sensors before the actual gaze measurement process. This preliminary information is pre-processed to establish the correct geometric model and field of view parameters, allowing the subsequent image processing to proceed efficiently with accurate reference data, thus maintaining both speed and precision.
Solution Approach 2:
The sensor system provides continuous feedback about mirror position to the processor, enabling real-time adaptation of image processing parameters. This feedback loop allows the system to maintain high processing speeds by using efficient algorithms while ensuring accuracy through dynamic parameter adjustment based on current mirror position data.
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
The system provides accurate determination of driver gaze direction and attention levels, enabling tailored interventions in advanced driver assistance systems by understanding the driver's focus within the vehicle cabin, thereby improving safety and functionality.
Implementation Method 1
A magnetic sensing device, such as a 3D hall effect sensor, to determine the orientation of the mirror head relative to the mounting structure
Data Source
AI summary
A vehicular driver monitoring system includes an interior rearview mirror assembly including a mirror head and a mirror reflective element and a driver monitoring camera that move together and in tandem with the mirror head. A sensing device is disposed at a pivot joint that attaches the mirror head at a mounting structure. The vehicular driver monitoring system, based on sensor data output by the magnetic sensing device, determines orientation of the mirror head relative to the mounting structure. With the mounting structure attached at the interior portion of the cabin of the vehicle, image data captured by the driver monitoring camera is processed at the ECU for monitoring of the driver of the vehicle, and image processing at the ECU of image data captured by the driver monitoring camera is based at least in part on the determined orientation of the mirror head relative to the mounting structure.