Driver Head Pose Assessment Using Relative Motion Sensor
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Solution Overview
Problem
Current driver distraction monitoring systems are costly and unreliable due to the need for sophisticated video imaging and processing to detect facial features like eyes, which can be obstructed by sunglasses or vary in distance, making it difficult to assess driver head pose effectively.
Innovation Solution
A method and apparatus using a relative motion sensor positioned rearward of the driver's head, such as on the headrest, to detect changes in head position and determine if the driver is paying attention to the forward field-of-view, with a signal processing method to infer and maintain a forward-looking head pose based on characteristic driver behaviors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If video imaging and processing is used to detect facial features, then driver head pose can be assessed, but system cost becomes too high for production vehicles
Solution Approach 1:
The patent extracts only the essential information needed for head pose assessment (relative head movement and orientation changes) rather than attempting to detect all facial features. By using a simple optical sensor to detect head movement relative to the headrest, the system achieves sufficient accuracy for distraction monitoring without the high cost of video imaging systems.
Solution Approach 2:
The patent replaces expensive video cameras and complex processing systems with a simple, low-cost optical sensor that detects relative head movement. This inexpensive sensor provides the necessary data for head pose assessment without requiring sophisticated optics or high-resolution imaging capabilities.
2Measurement precision
If video imaging is used to detect facial features, then head pose can be determined, but detection is hampered by obstructions like sunglasses
Solution Approach 1:
The patent extracts head pose information from head movement relative to the headrest rather than from facial features. This approach completely avoids the problem of facial obstructions since the sensor detects the position and movement of the head as a whole, not specific facial features that could be blocked by sunglasses or other obstructions.
3Measurement precision
If video imaging is used to detect facial features, then head pose can be assessed, but distance variation between imager and driver's face makes detection difficult
Solution Approach 1:
The patent combines the optical sensor with the headrest structure, creating an integrated system that moves with the headrest. This integration ensures that the sensor maintains a consistent reference frame relative to the driver's head position, automatically accommodating different driver distances and positions without requiring complex distance measurement or adjustment mechanisms.
4Measurement precision
If video imaging is used to detect facial features, then head pose can be determined, but controlled illumination of the driver's face is difficult
Solution Approach 1:
The patent extracts head pose information from relative head movement detection rather than from illuminated facial features. This eliminates the need for controlled illumination entirely, as the optical sensor detects head position changes relative to the headrest without requiring light to illuminate the driver's face.
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 provides a cost-effective and reliable assessment of driver head pose, enabling the detection of forward or non-forward attention without the need for high-resolution eye gaze detection, effectively reducing driver distraction monitoring costs while maintaining accuracy.
Implementation Method 1
a relative motion sensor positioned rearward of the driver's head, such as in or on the headrest of the driver's seat. The relative motion sensor detects changes in the position of the driver's head
Data Source
AI summary
The head pose of a motor vehicle driver with respect to a vehicle frame of reference is assessed with a relative motion sensor positioned rearward of the driver's head, such as in or on the headrest of the driver's seat. The relative motion sensor detects changes in the position of the driver's head, and the detected changes are used to determine the driver's head pose, and specifically, whether the head pose is forward-looking (i.e., with the driver paying attention to the forward field-of-view) or non-forward-looking. The determined head pose is assumed to be initially forward-looking, and is thereafter biased toward forward-looking whenever driver behavior characteristic of a forward-looking head pose is recognized.