Image Sensor Auto-Exposure Control With Same-Frame Adjustment
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Solution Overview
Problem
Autonomous vehicles experience frame delays in adjusting exposure settings of image sensors, leading to over-exposed or under-exposed frames that occupy storage space without improving vehicle operation.
Innovation Solution
Determine and implement exposure parameters during the same frame period by analyzing previous or pre-exposure frames, reducing latency and adjusting exposure settings dynamically based on frame characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If exposure settings are adjusted based on previous frame analysis, then image quality is improved, but frame delay increases causing over-exposed or under-exposed frames
Solution Approach 1:
The system performs preliminary exposure parameter adjustment within the same frame period by analyzing frame characteristics and calculating target exposure parameters before the frame is fully captured. This preliminary action eliminates the need for multi-frame delays, as the exposure settings are predetermined and applied immediately to the current frame, preventing both over-exposure and under-exposure while maintaining real-time image quality.
2Measurement precision
If multi-frame delay is used to adjust exposure settings, then exposure accuracy is improved, but storage space is wasted on unusable frames
Solution Approach 1:
The system performs self-service by completing the entire exposure adjustment process within a single frame period. The image sensor captures frame characteristics, the processor calculates target exposure parameters, and the adjusted exposure is applied all within the same frame cycle. This self-contained process eliminates the generation of over-exposed or under-exposed intermediate frames, ensuring that every captured frame is usable and worth storing, thereby optimizing storage space utilization.
3Loss of time
If exposure parameter adjustment is performed during frame period, then frame delay is reduced, but processing speed requirement increases
Solution Approach 1:
The processing workload is segmented into distinct phases that occur sequentially within the frame period: frame characteristic analysis, target exposure parameter calculation, and exposure adjustment application. This segmentation allows the system to distribute processing tasks efficiently, ensuring that each phase completes within its allocated time window. The segmented approach enables real-time processing speed requirements to be met while maintaining reduced frame delay, as each segment is optimized for its specific function and executes without unnecessary overhead.
Data Source
AI summary
Example embodiments relate to reducing auto-exposure latency. An example embodiment includes a method of reducing auto-exposure latency. The method includes determining, by a processor, a first setting of an exposure parameter for a first frame to be captured by an image sensor. The first setting of the exposure parameter is determined based at least in part on characteristics of a previous frame captured by the image sensor. The first setting of the exposure parameter is determined during a first frame period associated with capturing the first frame. The method also includes initiating, by the processor, a first frame exposure operation based on the first setting of the exposure parameter. During the first frame exposure operation, the image sensor captures the first frame during the first frame period.