Image Pickup Apparatus Expanding Dynamic Range via Multi-Exposure Synthesis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Digital cameras face challenges in capturing images with a wider brightness range, leading to underexposed shadows and overexposed highlights due to the limitations of their dynamic range, which existing HDR technologies partially address but not comprehensively.
Innovation Solution
An image pickup apparatus and method that synthesizes multiple images taken with different exposure amounts to create a single image with an expanded dynamic range, utilizing techniques such as repeated exposures, simultaneous multi-exposure settings, and beam splitting to capture a wider brightness range during both live-view and still-image recording operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single exposure setting is used to photograph a scene with wide brightness range, then the exposure amount can be optimized for either dark or bright sections, but the other section will be underexposed or overexposed respectively
Solution Approach 1:
The image data is segmented into multiple exposure versions (underexposed, normally exposed, overexposed) captured in separate photographing sessions. Each exposure version is processed independently to extract pixel values suitable for specific brightness regions, then synthesized together to create a final image that covers the entire brightness range with accurate exposure in each region.
Solution Approach 2:
The solution adds the dimension of multiple exposure settings by conducting photographing sessions with different exposure conditions. Instead of trying to optimize a single exposure setting, the system creates a multi-dimensional exposure space where pixel values from different exposure dimensions are selectively combined based on local brightness requirements.
2Adaptability or versatility
If multiple photographing sessions with different exposure conditions are conducted, then the brightness range coverage is improved, but the photographing time and processing complexity increase
Solution Approach 1:
The system performs preliminary photographing sessions to capture a set of underexposed, normally exposed, and overexposed images before main photographing. During main photographing, only the necessary exposure versions are captured based on the actual scene brightness range, reducing redundant photographing time while maintaining comprehensive brightness coverage.
Solution Approach 2:
The system captures more exposure versions than strictly necessary (underexposed, normally exposed, and overexposed), then selectively uses only the relevant portions during synthesis. This partial use of excessive data ensures complete brightness range coverage while allowing flexibility in handling different scene conditions.
3Adaptability or versatility
If multiple images with different exposure amounts are synthesized, then the dynamic range is expanded and gradation is improved, but the image processing complexity increases
Solution Approach 1:
The synthesis process applies local quality by selecting pixel values from different exposure versions based on local brightness characteristics. For each pixel position, the system determines which exposure version provides the most appropriate pixel value for that specific region, creating a synthesized image with optimized local quality across the entire brightness range.
Solution Approach 2:
The system changes exposure parameters (exposure amount) across multiple photographing sessions to capture images with different brightness characteristics. During synthesis, pixel values from these parameter-varied images are selectively combined, leveraging the parameter changes to achieve expanded dynamic range and improved gradation in the final image.
Data Source
AI summary
A digital camera has an image pickup unit which can obtain a set of plural input images with different exposure amounts by photographing the same subject; an image synthesizing unit which creates a synthesized image from the set of plural input images; a live-view image output unit which outputs a live-view image on the basis of the synthesized image obtained by synthesizing a set of n pieces of (n is an integer not less than 2) input images with different exposure amounts obtained from the photographing unit during a view display operation; and a recorded image creating unit which creates an image for recording on the basis of the synthesized image obtained by synthesizing a set of m pieces of (m is an integer not less than 2) input images with different exposure amounts obtained from the image pickup unit during main photographing in the image synthesizing unit.