Imaging Apparatus Exposure and Tone Correction for Highlight Control
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Solution Overview
Problem
Existing imaging technologies struggle to maintain the brightness of high brightness regions while correcting tone in dark portions of an image, leading to deviations from the user's intended brightness settings in highlight-weighted photometry.
Innovation Solution
An imaging apparatus with exposure control and tone correction units adjusts the exposure to align the representative brightness of high brightness regions with user-set targets and adjusts tone correction based on the brightness of dark portions to ensure the high brightness regions remain at the intended level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If tone correction is performed on dark portions to improve visibility, then the brightness of dark regions is enhanced, but the brightness of high brightness regions deviates from the target brightness set by the user
Solution Approach 1:
The patent applies different correction strengths to different regions of the image. The tone correction unit performs strong correction on dark portions while applying weakened correction to high brightness regions. This regional differentiation allows dark areas to be enhanced without causing the highlight regions to exceed the user's target brightness setting.
Solution Approach 2:
The patent dynamically adjusts the correction amount parameter based on regional brightness characteristics. By calculating the difference between actual and target brightness in high brightness regions, the system determines an appropriate weakening amount to apply to the tone correction, thereby maintaining parameter accuracy across different image regions.
2Measurement precision
If exposure control is performed to match target brightness in high brightness regions, then the representative brightness approaches the target value, but tone correction of dark portions causes the high brightness region brightness to increase beyond the target
Solution Approach 1:
The patent applies a counteracting measure by weakening the tone correction effect specifically in high brightness regions. This preliminary anti-action compensates for the potential over-correction that would occur if standard tone correction were applied uniformly, ensuring that the final brightness remains close to the user's target value.
Solution Approach 2:
The system calculates the brightness difference between the actual representative brightness and the target brightness in high brightness regions, then uses this feedback information to determine the appropriate weakening amount for tone correction. This closed-loop control ensures that tone correction does not cause excessive brightness increase in highlight areas.
Data Source
AI summary
An imaging apparatus includes at least one memory and at least one processor which function as: an exposure control unit configured to perform exposure control so that a representative brightness of a high brightness region of an image becomes a target brightness set by a user; and a tone correction unit configured to perform tone correction on a captured image, which was captured after performing the exposure control, based on a brightness of a dark portion that is a region having a brightness lower than the high brightness region, wherein the tone correction unit adjusts a correction amount of the tone correction so that the representative brightness of the high brightness region, which is corrected to be higher than the target brightness by the tone correction, becomes close to the target brightness.