In-Car Face Illumination Synchronized for Flicker-Free Video Calls
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Solution Overview
Problem
The existing illumination systems in vehicles fail to provide high-quality video recording of occupants' faces during video calls due to poor lighting directionality and flickering effects caused by artificial light sources, which are not synchronized with camera frame rates.
Innovation Solution
A system comprising a camera and controlled light sources, including LEDs or OLEDs, that synchronize their pulse frequency with the camera's frame rate, along with a control unit connected to light and camera, and additional light sources positioned to provide balanced illumination, using a face sensor to adjust light levels based on skin color and ambient conditions, and a glare shield to minimize scattered light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If semiconductor light sources (LEDs/OLEDs) are used to illuminate the occupant's face, then energy consumption is reduced and lifespan is extended, but flickering effects occur in video recordings due to unsynchronized operation with camera frame rates
Solution Approach 1:
The control unit operates the semiconductor light source periodically with a pulse frequency that matches the camera's frame rate. The light source is pulsed on and off in synchronization with each frame capture, ensuring continuous illumination for recording while maintaining energy efficiency characteristics of semiconductor lights.
Solution Approach 2:
The control unit receives the horizontal frequency signal from the camera and uses this feedback to adjust the pulse frequency of the light source accordingly. This closed-loop control ensures the light source operates in perfect synchronization with the camera frame rate, eliminating flickering in video recordings.
2Illumination intensity
If the light source is positioned to provide direct illumination to the occupant's face, then illumination intensity is improved, but glare and scattered light increase
Solution Approach 1:
The system employs multiple light sources positioned at different locations (above, below, and beside the occupant's face) rather than a single direct source. Each light source provides localized illumination from its specific position, creating balanced overall illumination that reduces glare while maintaining sufficient brightness on the face.
Solution Approach 2:
Instead of positioning the light source directly in front of the face (one-dimensional approach), the system distributes light sources across multiple spatial dimensions - above, below, left, and right of the face. This multi-dimensional illumination approach eliminates direct glare paths while providing comprehensive face coverage.
3Illumination intensity
If multiple light sources are used to provide balanced illumination, then illumination quality is improved, but device complexity increases
Solution Approach 1:
The control unit serves multiple functions simultaneously: it receives the camera's horizontal frequency signal, processes synchronization information, controls the pulse operation of multiple light sources, and adapts to different ambient light conditions via the light sensor. This multi-functionality reduces the need for separate control circuits for each component.
Solution Approach 2:
The system combines multiple light sources and control functions into a unified illumination system managed by a single control unit. The control unit integrates camera synchronization, light source control, and ambient light adaptation into one coordinated system, managing complexity through consolidation rather than separate independent controls.
4Reliability
If the light source operates at high pulse frequency to match camera frame rate, then flicker-free recording is achieved, but energy consumption increases
Solution Approach 1:
The light source operates in periodic pulse mode rather than continuous operation. By pulsing the light source only during camera frame capture intervals and maintaining synchronization with the frame rate, the system achieves flicker-free recording while minimizing energy consumption through duty cycle reduction.
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 solution ensures flicker-free, high-quality video recordings by synchronizing light sources with camera frame rates and providing balanced illumination, enhancing video conferencing quality and reducing glare, while allowing for adjustable lighting based on video call content and ambient conditions.
Implementation Method 1
at least one light source (3), having a main light emission direction (A)
Implementation Method 2
semiconductor-light sources as LEDs or OLEDs
Implementation Method 3
The system comprises at least one light sensor (7), which light sensor is connected to the control unit (6), and the light sensor is arranged to detect the light of the surrounding area
Data Source
AI summary
A system is provided for illuminating the face of an occupant for a video call in a car. At least one light source has a main light emission direction (A) which is directed toward the face of the occupant. The system also includes a camera provided to record the face of the occupant. The system controls the light source in such a way to obtain a flickering free recording of the face of the occupant.