Adaptive Camera Flash Exposure Control for Depth Variation
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Solution Overview
Problem
Existing camera technologies struggle to ensure optimal flash and exposure settings for images, particularly in scenes with large depth variations and varying ambient illumination, leading to issues like over- or under-exposure, reflections, and highlights, and do not adaptively adjust settings based on actual flash illumination effects.
Innovation Solution
A coherence model is used to relate intensity gradients in flash and ambient images, allowing for gradient projection to reduce undesirable reflections and highlights, and a brightness ratio process compensates for depth-related illumination differences, enabling adaptive camera setting estimation and high dynamic range image enhancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If flash unit is used to illuminate scene, then nearby objects are over-exposed, but distant objects are under-exposed
Solution Approach 1:
The patent applies local quality by processing different regions of the image separately - nearby objects are treated differently from distant objects. The system identifies regions based on depth information and applies different exposure correction factors to each region, allowing nearby objects to have their over-exposure corrected while distant objects receive appropriate illumination enhancement without creating uniformity issues.
Solution Approach 2:
The patent changes the exposure parameter dynamically based on the distance of objects from the flash unit. By using depth information, the system adjusts exposure settings locally for different depth planes, transforming the fixed exposure parameter into a variable parameter that adapts to the specific lighting conditions of each region.
2Manufacturing precision
If flash unit is used to illuminate scene, then details are enhanced for shallow-depth scenes, but reflections and highlights are produced
Solution Approach 1:
The patent extracts and removes harmful reflections and highlights from the image while preserving useful details. Using depth information and region identification, the system separates the image into regions containing reflections/highlights versus regions with useful detail, then applies selective processing to remove the harmful elements while maintaining the quality of the remaining areas.
Solution Approach 2:
The patent converts the harmful reflections and highlights into useful information by analyzing their position and characteristics. The depth information from reflections is used to infer scene structure, and the highlight patterns provide clues about surface properties, transforming these artifacts into beneficial data for image enhancement.
3Manufacturing precision
If camera settings are set adaptively based on actual flash illumination effects, then optimal images are acquired, but system complexity increases
Solution Approach 1:
The patent implements self-service by having the camera system automatically analyze its own flash illumination effects and adjust settings accordingly. The system captures test images, analyzes the actual illumination patterns, and uses this information to automatically determine optimal exposure settings for subsequent shots, eliminating the need for manual intervention or complex external control systems.
Solution Approach 2:
The patent employs feedback mechanisms where the system continuously monitors the actual flash illumination effects through captured images, compares these against desired outcomes, and adjusts settings accordingly. This closed-loop approach allows the camera to learn from actual performance and automatically optimize future shots without requiring complex pre-programmed settings.
Data Source
AI summary
A camera is configured to adaptively determine camera settings. The camera includes a plurality of sensors elements configured to acquire a current image of a scene according to a current set of camera settings. A number of sensor elements having a set of desirable properties is measured. Then, a next set of camera settings that maximize an overall number of sensor elements having the set of desirable properties is determined to acquire a next better image.