Vehicle Lamp Unit Timing Control for Camera Exposure
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Solution Overview
Problem
Visible light cameras struggle to capture images effectively at night due to varying brightness levels within the vehicle headlamp's irradiation area, leading to overexposure or underexposure issues.
Innovation Solution
A vehicle monitoring system that includes a lamp unit with a first light source for a diffusion area and a second light source for a higher luminance area, combined to form a light distribution pattern, and a controller that controls the emission timing of the second light source and image capturing timing of the camera to ensure only the first light source is active during image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the visible light camera captures images using the vehicle headlamp's light distribution area, then the camera can capture the periphery of the vehicle at night, but overexposure or underexposure occurs due to varying brightness levels in different areas of the light distribution pattern
Solution Approach 1:
The light distribution pattern is segmented into multiple areas with different luminance characteristics (strongly irradiated area and weakly irradiated area). The controller selectively controls the second light source based on the camera's field angle to ensure uniform illumination across the entire capture area, preventing both overexposure in bright areas and underexposure in dark areas.
Solution Approach 2:
The system dynamically adjusts the emission timing of the second light source based on real-time detection of the camera's field angle and the corresponding light distribution pattern. This dynamic control ensures that the illumination conditions are continuously optimized for uniform exposure across the entire image capturing area.
2Area of stationary object
If the second light source is activated to increase luminance in certain areas, then the light distribution pattern provides better illumination coverage, but the high-luminance areas cause overexposure in the captured images
Solution Approach 1:
The controller implements periodic action by selectively activating the second light source only during specific time periods when the visible light camera is not capturing images in the high-luminance area. This temporal separation allows the system to maintain broad light distribution coverage while preventing overexposure in captured images.
Solution Approach 2:
The controller performs preliminary action by detecting the camera's field angle and determining the appropriate emission timing of the second light source before image capture occurs. This advance control ensures that high-luminance areas are illuminated when needed for coverage but deactivated before the camera captures images, preventing overexposure.
3Manufacturing precision
If image capturing conditions are adjusted to suit the strongly irradiated area, then overexposure is prevented in bright areas, but underexposure occurs in weakly irradiated areas
Solution Approach 1:
The system applies local quality by providing different illumination intensities to different areas of the light distribution pattern. The second light source is selectively activated to enhance luminance in specific local areas (weakly irradiated areas) while maintaining appropriate exposure levels in other areas, achieving both local brightness uniformity and overall image exposure accuracy.
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 allows for optimal image capturing conditions across the entire field angle of the visible light camera, preventing overexposure or underexposure and facilitating image processing by suppressing recognition of high-luminance cut-off lines in the image data.
Implementation Method 1
a first light source configured to emit light that forms a first light distribution area on a virtual vertical screen
Implementation Method 2
a second light source configured to emit light that forms a second light distribution area having a luminance higher than that of the first light distribution area
Data Source
AI summary
A vehicle monitoring system includes a lamp unit that includes a first light source configured to emit light that forms a first light distribution area on a virtual vertical screen disposed at a predetermined distance from a vehicle, and a second light source configured to emit light that forms a second light distribution area having a luminance higher than that of the first light distribution area on the virtual vertical screen, and forms a predetermined light distribution pattern on the virtual vertical screen by the first light distribution area and the second light distribution area; a visible light camera that captures a periphery of the vehicle; and a controller configured to control at least one of an emission timing of the second light source or an image capturing timing of the visible light camera.