Camera Exposure Control for Traffic Light and Road Sign Detection
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Solution Overview
Problem
Existing imaging control apparatuses struggle to minimize color identification failures and flicker on images captured by cameras due to varying luminance levels of traffic lights and road signs, leading to saturation issues.
Innovation Solution
An imaging control apparatus and program that detect the luminance of objects in the image and adjust the exposure time of the camera based on the type of object detected, using different exposure times for traffic lights and electronic road signs to prevent saturation and ensure stable color identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the exposure time is increased to capture low-luminance objects (road signs), then the risk of flicker appearance is reduced, but the quantity of light from high-luminance objects (traffic lights) exceeds the saturated light quantity, causing color identification failure
Solution Approach 1:
The patent applies dynamics by making the exposure time adjustable and variable based on detected object characteristics. The exposure time is not fixed but dynamically changed according to whether high-luminance objects (traffic lights) or low-luminance objects (road signs) are detected, allowing the system to adapt to different lighting conditions and object types.
Solution Approach 2:
The patent applies local quality by treating different detected objects with different exposure time settings. High-luminance objects (traffic lights) trigger a shorter exposure time, while low-luminance objects (road signs) trigger a longer exposure time. This localized adjustment based on object-specific characteristics resolves the contradiction between preventing flicker and avoiding saturation.
2Measurement precision
If the exposure time is decreased to prevent saturation from high-luminance objects (traffic lights), then color identification is improved, but the quantity of light from low-luminance objects (road signs) becomes insufficient, causing flicker appearance
Solution Approach 1:
The system dynamically adjusts exposure time based on real-time detection results. When low-luminance objects are detected, the exposure time is increased to ensure sufficient light capture and prevent flicker. When high-luminance objects are detected, the exposure time is decreased to prevent saturation. This dynamic adjustment resolves the contradiction between color identification accuracy and flicker prevention.
Solution Approach 2:
The patent changes the exposure time parameter based on the detected object's luminance characteristics. By detecting whether high-luminance or low-luminance objects are present and adjusting the exposure time parameter accordingly, the system resolves the contradiction between preventing saturation and preventing flicker.
3Device complexity
If a single exposure time setting is used for all objects, then the device complexity is reduced, but it cannot simultaneously prevent both color identification failure and flicker appearance
Solution Approach 1:
The patent segments the imaging conditions by detecting and categorizing different object types (high-luminance traffic lights vs. low-luminance road signs). This segmentation allows the system to apply different exposure time settings for different object categories, improving image quality stability without requiring a completely complex multi-parameter control system.
Solution Approach 2:
The system uses feedback from the detection unit to automatically adjust the exposure time setting. The detection unit identifies object characteristics and provides feedback to the control unit, which then adjusts the exposure time accordingly. This feedback mechanism maintains image quality stability without requiring manual intervention or overly complex pre-programming.
Data Source
AI summary
An imaging control apparatus is configured to detect a first object and a second object appearing on an image captured by a camera. The first object is higher in luminance than the second object. When the second object is not detected on the image, the imaging control apparatus works to adjusts an exposure time of the camera to a first exposure time which is used when the first object is detected. Alternatively. When the second object is detected, the imaging control apparatus adjusts the exposure time of the camera to a second exposure time which is longer than the first exposure time. This eliminates a failure in identifying colors on the image and also minimizes a risk of appearance of flicker on the image.