Overlapping Exposure Image Combinations for Ghosting-Reduced HDR
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Solution Overview
Problem
HDR mode in digital cameras often suffers from ghosting due to objects moving between different exposure shots, leading to blurry or distorted images, and traditional techniques to reduce this by shortening exposure time are inadequate.
Innovation Solution
A method involving overlapping exposure times of long and short-exposure images, using an interleaved readout technique to minimize temporal separation and reduce ghosting, combined with artificial creation of exposure images from multiple images captured during overlapping periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If long-exposure images are used to capture more light and improve dynamic range, then the dynamic range increases, but ghosting artifacts occur due to object motion during the extended exposure period
Solution Approach 1:
The patent segments the exposure process into multiple discrete images captured at different time points (first image, second image, third image). Instead of a single long exposure, the exposure is divided into multiple shorter exposures that are then combined through image processing to achieve the desired dynamic range while minimizing motion artifacts.
Solution Approach 2:
The patent merges multiple images (first image, second image, third image) with overlapping exposure periods into a composite long-exposure image. By combining these temporally separated images with minimal temporal gap, the system achieves extended dynamic range while reducing ghosting compared to traditional single long-exposure methods.
2Illumination intensity
If exposure time is extended to improve dynamic range, then more light is captured, but temporal separation between exposures increases causing motion-related artifacts
Solution Approach 1:
The patent uses the second image, captured during the overlapping exposure period, as a preliminary reference for HDR processing. This preliminary capture allows the system to perform high dynamic range processing that compensates for motion artifacts before final image generation, reducing the impact of temporal separation.
Solution Approach 2:
The patent ensures continuity by designing overlapping exposure periods where the second image is captured while both first and third images are being exposed. This continuous capturing approach minimizes temporal gaps and ensures seamless integration of multiple exposures, maintaining useful action throughout the imaging process.
3Illumination intensity
If traditional HDR techniques are used with separate long and short exposure shots, then dynamic range is improved, but ghosting occurs due to objects moving between different exposure shots
Solution Approach 1:
The patent introduces dynamic adjustment of exposure timing and overlapping periods. The exposure scheme is dynamically designed so that the second image is captured during the overlapping period of first and third images, allowing flexible adaptation to scene conditions and motion characteristics, thereby improving reliability while maintaining dynamic range.
Solution Approach 2:
The patent changes the temporal parameters of exposure by introducing overlapping periods and using multiple images with different exposure times. By adjusting exposure duration, timing, and overlap, the system optimizes both dynamic range and image quality, reducing ghosting artifacts while maintaining high dynamic range performance.
Data Source
AI summary
Multiple images that include a first image, a second image, and a third image are received. The multiple images are such that the second image is temporally between the first image and the third image. The first image, the second image, and the third image are combined to obtain a long-exposure image. High dynamic range processing is applied to the second image and the long-exposure image to obtain an output image with a larger dynamic range than a dynamic range of the second image. The high dynamic range processing uses the second image as a short-exposure image. An image based on the output image is transmitted, stored, or displayed.