Light Field Camera Eclipse Compensation via Signal Shifting
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Solution Overview
Problem
Conventional light field cameras face challenges in obtaining accurate ray space information due to positioning inaccuracies of optical elements, leading to difficulties in generating high-quality output images, especially during lens eclipses, as existing techniques do not adequately address angle accuracy and output image generation in such situations.
Innovation Solution
An image capture apparatus comprising an imaging optical system, image sensor, pupil division unit, incident angle determination unit, image shift unit, and image generation unit, which limits light beams to specific pupil areas, determines incident angles, shifts electric signals based on these angles, and synthesizes signals to exclude areas affected by eclipses, ensuring high-quality image generation even during lens eclipses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a light field camera is used to acquire ray space information, then the ability to change focus position after shooting is improved, but positioning accuracy of optical elements becomes difficult to maintain due to eclipse effects
Solution Approach 1:
The patent replaces mechanical positioning measurement with optical signal processing. Instead of relying on precise mechanical positioning of the microlens array, the system uses the pupil division unit to optically separate light beams from different pupil areas, and the image shift unit to computationally correct for eclipse effects, thereby maintaining measurement precision without requiring high mechanical positioning accuracy
Solution Approach 2:
The patent introduces a microlens array as an intermediary optical element that divides the pupil area into multiple regions. This intermediary structure enables the system to capture ray space information from different angles simultaneously, allowing focus adjustment after shooting while the image shift unit compensates for eclipse effects on the microlens array positioning
2Device complexity
If conventional signal processing is used in light field cameras, then device complexity is reduced, but angle accuracy of the photographing lens deteriorates during eclipse
Solution Approach 1:
The patent segments the pupil area into multiple distinct regions using the microlens array, with each microlens corresponding to a specific pupil area. This segmentation allows the system to track and compensate for angle changes in each region independently, maintaining angle accuracy during eclipse while using relatively simple per-region signal processing
Solution Approach 2:
The patent implements dynamic angle determination that adapts to eclipse conditions. The incident angle determination unit calculates angles based on the actual light beam paths observed in each pupil area, allowing the system to dynamically adjust for eclipse effects rather than relying on fixed geometric assumptions, thereby maintaining angle accuracy without excessive processing complexity
3Manufacturing precision
If accurate ray information is required for reconstruction, then image quality is improved, but the system becomes sensitive to positioning errors of optical elements
Solution Approach 1:
The patent implements a feedback mechanism where the image shift unit uses the determined incident angles to correct the positions of light beams during image reconstruction. By feeding back the actual measured angles to the reconstruction process, the system compensates for positioning errors in the microlens array, maintaining image quality while reducing sensitivity to manufacturing and positioning tolerances
Solution Approach 2:
The patent changes the parameter used for reconstruction from fixed geometric relationships to dynamically determined incident angles. Instead of relying on predetermined microlens positions, the system measures and uses actual light beam angles for each pupil area, thereby maintaining high image quality while becoming less sensitive to positioning errors in the optical elements
Data Source
AI summary
An image capture apparatus comprises an imaging optical system, an image sensor, a pupil division unit which limits a light beam entering each pixel on the image sensor to a specific pupil area of the imaging optical system, an incident angle determination unit which determines an incident angle to each pixel on the image sensor, an image shift unit which shifts an electric signal obtained from the image sensor, based on the incident angle determined by the incident angle determination unit and a position of a plane on which image generation is performed, and an image generation unit which synthesizes electric signals obtained from the image shift unit.