Camera Exposure Adjustment via Virtual Image Feature Analysis
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Solution Overview
Problem
Conventional camera exposure adjustment methods fail to accurately set exposure values in varied lighting environments, particularly in backlight photography, leading to improperly exposed images, especially when photographing moving objects or in unknown environments.
Innovation Solution
An apparatus and method that generate virtual images through gamma correction, extract feature values such as edge or gradient information, and adjust camera exposure based on a reference brightness estimated from these features, iteratively converging the exposure to optimal levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If camera exposure is determined based on average light intensity of all pixels, then the exposure calculation is simple, but the exposure value becomes inaccurate in varied lighting environments such as backlight photography
Solution Approach 1:
The patent applies local quality by analyzing specific regions of the image rather than treating all pixels uniformly. It identifies a first region (typically the foreground or subject area) and a second region (background) separately, calculating exposure based on the first region's characteristics while considering the second region's lighting conditions. This regional differentiation allows accurate exposure determination in backlight scenarios where overall average intensity fails.
2Measurement precision
If multiple images are used for HDR function, then exposure determination accuracy improves, but image alignment problems occur when photographing moving objects
Solution Approach 1:
The patent employs preliminary action by pre-defining region boundaries and characteristics before image capture. It establishes the first and second regions based on scene analysis, then uses these pre-established regions to guide exposure calculation from a single image. This approach eliminates the need for multiple image captures and subsequent alignment operations, achieving accurate exposure determination without the complexity of HDR processing.
3Measurement precision
If a specific region is preset as region of interest, then camera exposure can be adjusted for best view, but the method is impractical when the camera is not fixed or in unknown environments
Solution Approach 1:
The patent implements dynamics by making region identification adaptive rather than static. It dynamically determines the first and second regions based on real-time scene analysis, lighting conditions, and image content characteristics. This dynamic region segmentation allows the system to automatically adapt to various shooting scenarios including backlight photography, moving objects, and unknown environments, eliminating the need for manual region presetting while maintaining exposure accuracy.
Data Source
AI summary
As an apparatus for adjusting camera exposure, the apparatus includes: a virtual image generator generating a plurality of virtual images by changing brightness of an image photographed by a camera; a feature image generator generating a plurality of feature images respectively indicating features of the plurality of virtual images; and an exposure controller corresponding a feature value of the plurality of feature images to brightness, estimating reference brightness that corresponds to the maximum feature value, increasing camera exposure when the reference brightness is brighter than the photographed image, and decreasing the camera exposure when the reference brightness is darker than the photographed image.