Multi-Exposure Motion Image Correction via Luminance Mapping
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Solution Overview
Problem
Existing methods for correcting multi-exposure motion images, such as those used in HDR photography, fail to effectively address camera shake and moving objects, leading to ghosting, blurring, and loss of detail information due to complex processing and inaccurate motion area detection.
Innovation Solution
A method involving a luminance mapping function to correct extended frames by calculating a global motion vector and correcting local error pixels, allowing for effective motion correction between multi-frame exposure images, including camera and object motion, without the need for pre-calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motion correction method using bi-directional prediction and gradient-based optical flow is applied, then motion correction capability is improved, but device complexity and processing time increase significantly
Solution Approach 1:
The patent segments the correction process into distinct stages: luminance mapping first, then motion vector calculation, and finally local motion correction. This segmentation allows each stage to be optimized independently, reducing overall complexity while maintaining correction effectiveness.
Solution Approach 2:
The patent performs luminance mapping as a preliminary action before motion correction. By equalizing luminance levels between frames first, the subsequent motion estimation becomes more accurate and simpler, as it no longer needs to compensate for luminance differences.
2Stability of the object's composition
If luminance mapping is applied to all areas before motion detection, then luminance consistency is improved, but motion area detection accuracy deteriorates
Solution Approach 1:
The patent applies different processing strategies to different areas: luminance mapping is applied globally, but motion detection and correction are applied locally only where needed. This allows luminance consistency to be maintained while preserving accurate motion area detection by using original frame data for motion analysis.
3Productivity
If direct pixel replacement is used for motion areas, then processing speed is improved, but detail information is lost
Solution Approach 1:
The patent introduces motion vectors as an intermediary representation between the original frames and the corrected image. Instead of direct pixel replacement, motion vectors encode the displacement information, allowing for more accurate interpolation and preservation of detail information during the correction process.
4Measurement precision
If camera response curve calibration is performed, then luminance mapping accuracy is improved, but device complexity and calibration requirements increase
Solution Approach 1:
The patent replaces the complex, permanent camera response curve calibration with a simpler, frame-specific luminance mapping approach. Instead of requiring precise sensor characterization, the method uses statistical luminance analysis of the actual frames being processed, achieving sufficient accuracy without expensive calibration procedures.
Data Source
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AI summary
A method and an apparatus for correcting a multi-exposure motion image are disclosed, where the method includes: determining a luminance mapping function, where the luminance mapping function is a luminance mapping relationship between a reference frame and multiple extended frames; mapping a luminance of an extended frame by using the luminance mapping relationship to obtain a virtual frame; calculating a global motion vector between the virtual frame and the reference frame; correcting a pixel of the extended frame according to the global motion vector to obtain a first extended frame after correction; detecting a pixel of the first extended frame according to the reference frame to obtain a local error pixel of the first extended frame; and correcting a luminance of the local error pixel of the first extended frame to obtain a second extended frame after correction. Embodiments of the present invention solve a technical problem in the prior art that a multi-exposure frame motion image cannot be effectively corrected.