Flicker-Aware HDR Image Combining with Single-Exposure Gain Switching
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Solution Overview
Problem
Existing HDR rendering techniques fail to effectively combine images under flickering light sources, leading to unnatural rendering due to inconsistencies in luminance levels, and adjusting the combining ratio to reduce flicker influence can reduce the dynamic range of the combined image.
Innovation Solution
An apparatus captures multiple images with different gains using one exposure if flicker is detected, and multiple exposures if not detected, to combine them into a high dynamic range image, reducing flicker influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple images are captured under different exposure conditions for HDR rendering, then the dynamic range of the combined image is extended, but inconsistencies in luminance levels occur due to flickering light sources
Solution Approach 1:
The system performs preliminary detection of flicker characteristics (frequency and amplitude) before capturing HDR images. Based on this detection, it pre-determines the optimal capture timing synchronized with the flicker cycle, ensuring that images are captured at consistent phases of the flicker waveform to maintain luminance consistency while still achieving extended dynamic range.
Solution Approach 2:
The system utilizes periodic action by synchronizing image capture timing with the periodic flicker cycle of the light source. By capturing images at specific phases of the flicker waveform (e.g., at peak luminance or at consistent intervals), the system maintains luminance consistency across multiple exposures while still achieving HDR效果.
2Reliability
If the combining ratio is adjusted to reduce flicker influence, then luminance consistency improves, but the dynamic range of the combined image is reduced
Solution Approach 1:
The system performs preliminary detection of flicker characteristics before HDR combining, and based on this detection, pre-determines both the capture timing and the optimal combining ratio. This allows the system to use a higher weight for images captured at favorable flicker phases while compensating with appropriate gain adjustments, thereby maintaining both luminance consistency and dynamic range.
Solution Approach 2:
The system dynamically changes multiple parameters including capture timing, gain values, and combining ratios based on detected flicker characteristics. By coordinating these parameter changes, the system can reduce flicker influence through optimized combining ratios while compensating for any dynamic range loss through gain adjustments and selective weighting of images captured at optimal phases.
3Illumination intensity
If multiple exposures are performed to capture images for HDR, then dynamic range is extended, but capture time increases
Solution Approach 1:
The system utilizes periodic action by synchronizing image capture with the periodic flicker cycle of the light source. This allows the system to capture multiple images with different effective exposures during a single continuous exposure interval, achieving HDR效果 without the time penalty of sequential multi-exposure capture.
Solution Approach 2:
The system merges multiple capture strategies into a single exposure operation. By combining synchronized multi-image capture during one exposure event with gain adjustments and optimized combining algorithms, the system achieves HDR dynamic range extension while reducing capture time to essentially one exposure duration rather than multiple sequential exposures.
Data Source
AI summary
An apparatus includes an image sensor configured to capture a plurality of images, at least one memory configured to store instructions, and at least one processor in communication with the at least one memory and configured to execute the instructions to determine whether a flicker has occurred, and combine the plurality of images into a combined image. If the flicker occurs, the image sensor captures the plurality of images through application of different gains by performing one exposure. If the flicker does not occur, the image sensor captures the plurality of images by performing a plurality of exposures.