Image Capturing Apparatus Adaptive Dynamic Range Control
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Solution Overview
Problem
Conventional image capturing devices face challenges in managing dynamic range, leading to loss of tone detail in high contrast scenes, requiring users to manually set tone priority modes and often resulting in suboptimal image capture results due to the need for scene discrimination.
Innovation Solution
An image capturing apparatus and method that dynamically adjust sensitivity and tone characteristics based on face detection and scene analysis, using a combination of face detection circuits, histogram creation, and sensitivity adjustment to expand or contract the dynamic range according to the presence of blown-out highlights and scene conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If tone priority mode is used to suppress blown-out highlights, then high luminance portions are improved, but user operation complexity increases and scene discrimination is required
Solution Approach 1:
The camera system automatically performs scene analysis and determines optimal dynamic range settings without requiring user intervention. The system self-adjusts sensitivity and tone characteristics based on detected scene conditions, eliminating the need for users to manually select tone priority modes or discriminate scenes.
Solution Approach 2:
The system uses histogram analysis and scene detection results to provide feedback for automatic adjustment of dynamic range parameters. By analyzing the captured image's luminance distribution and comparing it with predefined scene patterns, the system dynamically optimizes sensitivity and tone characteristics to prevent blown-out highlights while maintaining ease of operation.
2Illumination intensity
If manual scene discrimination is required to set tone priority mode, then high luminance control is improved, but ease of operation deteriorates
Solution Approach 1:
The camera system automatically performs scene analysis and determines optimal dynamic range settings without requiring user intervention. The system self-adjusts sensitivity and tone characteristics based on detected scene conditions, eliminating the need for users to manually select tone priority modes or discriminate scenes.
3Illumination intensity
If dynamic range is expanded using special image sensor with different sensitivity light receiving elements, then dynamic range is improved, but manufacturing cost increases
Solution Approach 1:
The system achieves dynamic range expansion by changing operational parameters (sensitivity settings and tone characteristics) rather than using specialized hardware. By adjusting the sensitivity of existing light receiving elements and applying appropriate tone curves during image processing, the system expands dynamic range without requiring expensive dual-sensitivity sensors.
Solution Approach 2:
The invention replaces the mechanical/optical approach of using physical dual-sensitivity light receiving elements with an electronic/software-based approach. The system uses image processing techniques including histogram analysis, sensitivity adjustment, and tone characteristic modification to achieve dynamic range expansion that would otherwise require specialized hardware.
4Device complexity
If fixed sensitivity setting is used, then device complexity is reduced, but adaptability to different scenes deteriorates
Solution Approach 1:
The system transitions from fixed sensitivity settings to dynamic, scene-adaptive sensitivity control. By continuously analyzing the captured image's histogram and comparing it with scene patterns, the system automatically adjusts sensitivity and tone characteristics to match the specific scene conditions, enabling adaptability while maintaining simple device architecture.
Data Source
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AI summary
An image capturing apparatus determines a scene of a captured image, and, depending on the scene determination result, performs image capture with an expanded dynamic range, or performs a dynamic range contraction process based on the captured image. In the case of executing the dynamic range expansion process, the image capturing apparatus performs image capture at a decreased ISO speed, and performs tone correction for compensating the decrease in ISO speed with respect to the captured image. The image capturing apparatus is thereby capable of performing image capture with a dynamic range that takes into consideration the subject and the scene.