Infrared Light Source Control for Occlusion-Safe Driver Monitoring
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Solution Overview
Problem
Infrared radiation used in driver monitoring systems can pose safety hazards due to prolonged exposure, especially when a portion of the human anatomy occludes the light source, making existing safety measures impractical.
Innovation Solution
A control system that modulates infrared light sources based on image brightness analysis to detect occlusion, adjusting power levels or switching off sources when occlusion is detected, using a sequenced illumination method and image processing to ensure safe exposure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If infrared light sources are used continuously for driver monitoring, then monitoring performance is improved, but tissue heating and burn risk increase
Solution Approach 1:
The system implements periodic illumination by alternating between different infrared light sources in a sequenced manner rather than continuous operation. Each LED is activated for a specific duration followed by a pause, allowing tissue to cool down between exposures while maintaining continuous monitoring capability through multiple sources.
Solution Approach 2:
The control system dynamically adjusts the duty cycle and illumination parameters based on detected conditions. When occlusion is detected, the system modifies the illumination pattern by reducing duty cycle or switching to alternative LEDs, making the exposure regime adaptive rather than static to prevent overheating.
2Measurement precision
If infrared light sources are positioned close to the driver's face for effective monitoring, then image quality is improved, but occlusion risk and tissue heating increase
Solution Approach 1:
The system divides the illumination function across multiple separate infrared LEDs positioned at different locations rather than relying on a single light source. This segmentation allows the system to maintain close positioning for image quality while having alternative sources available if one is occluded, and enables periodic activation patterns to reduce thermal load.
3Object-affected harmful factors
If occlusion detection is implemented to prevent tissue damage, then safety is improved, but system complexity increases
Solution Approach 1:
The system uses the existing imaging camera to detect occlusion by analyzing the captured images for signs of occlusion, rather than requiring separate dedicated sensors. The same hardware components perform dual functions: imaging for driver monitoring and occlusion detection for safety, eliminating the need for additional complexity.
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
Ensures continuous monitoring while minimizing infrared radiation exposure risks by dynamically controlling light source intensity and preventing tissue damage, enhancing safety and performance in driver monitoring systems.
Implementation Method 1
one or more infrared light sources for illuminating a driver's face
Implementation Method 2
infrared light emitting diodes (LEDs)
Implementation Method 3
The reflected light is imaged by an infrared camera sensor
Implementation Method 4
When a person's tissue absorbs infrared light, the consequence is usually that a person feels warmth in the area exposed. Since infrared radiation works to get molecules moving, a moderate dose of infrared radiation will simply heat up any living tissue
Data Source
AI summary
A disclosed monitoring system includes infrared light sources that illuminate a subject in a sequenced manner and a camera that captures images of the subject during periods in which the subject is illuminated by one of the light sources. The system includes a processor that analyzes captured images to determine a brightness measure of the images, and a controller controls output power of the infrared light sources in response to the brightness measure. In response to the processor detecting a brightness measure below a predetermined brightness threshold, the controller is configured to switch off or reduce an output illumination intensity of one of the infrared light sources. A disclosed method further determines whether an emission source is occluded by modulating an intensity of an electromagnetic emission source, detecting whether the modulation pattern is present in captured images, and determining that the emission source is occluded based on the detected modulation.