Vehicle Camera Exposure Control via Forward Brightness Prediction
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Solution Overview
Problem
Existing exposure control systems for vehicle-mounted cameras struggle to accurately adjust exposure in response to rapid changes in brightness, leading to reduced recognition accuracy due to delayed adjustment after significant brightness variations.
Innovation Solution
An exposure control apparatus that measures and predicts brightness changes in a photometric area farther from the vehicle than the recognition area, allowing for timely exposure adjustments based on detected brightness variations, thereby improving the camera's ability to follow changes in brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If exposure control is performed based on real-time brightness detection of the recognition area, then the system responds to current lighting conditions, but it cannot anticipate sudden brightness changes before they occur
Solution Approach 1:
The system performs preliminary brightness measurements in a photometric area located ahead of the recognition area in the image. By measuring brightness in advance in this forward region, the system predicts upcoming brightness changes before they affect the recognition area, enabling proactive exposure control that reduces time loss while maintaining measurement precision through dedicated photometric sampling.
2Productivity
If the system waits to detect saturation signals before adjusting exposure, then it avoids unnecessary adjustments, but exposure control is delayed until after brightness changes occur
Solution Approach 1:
The system establishes a feedback mechanism by continuously monitoring brightness in the photometric area and comparing it across sequential images. This feedback loop detects brightness variation trends and triggers exposure control adjustments proactively, improving reliability by maintaining recognition accuracy during brightness transitions while preserving efficiency through condition-based activation rather than continuous adjustment.
3Ease of operation
If exposure control adjusts based on current recognition area brightness, then it maintains proper exposure for current conditions, but it cannot follow rapid brightness variations that occur between measurement cycles
Solution Approach 1:
The system adds a spatial dimension to brightness measurement by introducing a photometric area positioned ahead of the recognition area in the image field. This dimensional shift allows the system to capture brightness information from a forward region, enabling prediction of upcoming brightness changes and improving speed of response while maintaining operational simplicity through the same exposure control mechanism.
Data Source
AI summary
The exposure control apparatus is for performing exposure control for a camera mounted on a vehicle in accordance with brightness of a recognition area set in an image ahead of the vehicle taken by the camera. The exposure control apparatus includes a measuring means for measuring brightness of a photometric area showing a landscape more distant from the vehicle than a landscape shown by the recognition area in each of images successively taken by the camera, a detection means for detecting brightness variation with time of the photometric area based on measurement results by the measuring means for images taken by the camera at different times, and a control means configured to predict a timing at which the brightness of the recognition area changes based on the brightness variation with time of the photometric area, and perform exposure control of the camera at the predicted timing.