Two-Stage Burst Image Frame Merging for Dynamic Range
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Solution Overview
Problem
Conventional camera systems face challenges in processing multiple raw frames captured under varying lighting conditions, particularly in preserving color appearance and dynamic range, due to non-linearity with integration time and ISO, especially when noise is present.
Innovation Solution
A two-stage merging method for burst image frames, where frames are captured at an underexposed setting, aligned, and merged using key frames, allowing for scalable signal levels and noise reduction, effectively extending the dynamic range while preserving highlight details.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple raw frames are captured and merged to extend dynamic range, then image quality and noise reduction are improved, but processing complexity and computational load increase
Solution Approach 1:
The patent divides the burst frames into multiple groups and processes each group separately through staged merging operations. Instead of processing all frames simultaneously, the system segments them into manageable batches, reducing the computational complexity of each individual processing step while achieving the same overall dynamic range extension and noise reduction效果
Solution Approach 2:
The patent performs preliminary processing on individual frames within each group before merging them. Key frames are selected and prepared in advance, and alignment operations are performed preliminarily to facilitate the subsequent merging process. This preliminary action reduces the complexity of the final merging operation by pre-organizing the data structure
2Reliability
If frames are captured at underexposed settings to preserve highlight details, then dynamic range is extended, but image brightness and signal level decrease
Solution Approach 1:
The patent merges multiple underexposed frames to combine their signal levels. By aligning and merging frames captured at the same underexposed setting, the system accumulates signal strength while preserving the highlight details captured in each individual frame. The merging process effectively increases the signal level without requiring overexposed captures, thus extending dynamic range while maintaining image brightness through computational combination
3Measurement precision
If multiple frames are aligned and merged to reduce noise, then signal-to-noise ratio is improved, but processing time and computational resources increase
Solution Approach 1:
The patent segments the burst sequence into multiple groups that can be processed in parallel or sequential batches. Each group undergoes alignment and merging independently, which reduces the processing time compared to handling all frames in a single sequential operation. The segmentation allows for more efficient utilization of computational resources while maintaining the noise reduction benefits of frame merging
Solution Approach 2:
The patent processes frames in multiple passes rather than attempting to process all frames simultaneously in a single operation. By performing partial processing on subsets of frames and progressively building up the final result, the system reduces the peak computational load and processing time while still achieving the noise reduction benefits of comprehensive frame merging
Data Source
AI summary
A method of multiple-exposure multiple-frame image capture, comprising, capturing a first group of frames at an underexposed setting, selecting a first key frame from the first group of frames, aligning the first group of frames to the first key frame, merging the first group of frames into one first frame, capturing a second group of frames at the underexposed setting, selecting a second key frame from the second group of frames, aligning the second group of frames to the second key frame, merging the second group of frames into one second frame, selecting a main group of frames based on the first key frame and the second key frame, aligning the first key frame and the second key frame based on the main group of frames and merging the first key frame and the second key frame based on the main group of frames.