Low-light Video Frame Enhancement via Multi-Exposure Fusion
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Solution Overview
Problem
Low-light scenes in video capture result in very dark frames, leading to poor visual quality due to insufficient exposure time, which existing image processing techniques have not adequately addressed.
Innovation Solution
A method that combines image data from multiple frames with different exposure durations to enhance brightness and color quality, using a processor and video acquisition system with separate image acquisition subsystems to capture sharp, under-exposed and well-exposed images, and applying brightness and color information from well-exposed images to under-exposed images to generate enhanced versions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If exposure time is increased to improve brightness in low-light scenes, then image brightness is improved, but image sharpness deteriorates due to motion blur
Solution Approach 1:
The patent segments the image acquisition process into two distinct passes: a first pass with longer exposure time to capture brightness information, and a second pass with shorter exposure time to capture sharpness information. This segmentation allows each pass to optimize for its specific purpose without compromise
Solution Approach 2:
The patent merges the brightness information from the first image with the sharpness information from the second image to produce an enhanced output image. This combining of complementary information from multiple sources resolves the contradiction between brightness and sharpness
2Manufacturing precision
If multiple image acquisition passes are used to capture both bright and sharp images, then image quality is improved, but acquisition time increases
Solution Approach 1:
The patent maintains continuity of useful action by overlapping the two acquisition passes in time. The first pass continues acquiring brightness information while the second pass simultaneously acquires sharpness information, maximizing the utilization of acquisition time rather than sequential processing
Solution Approach 2:
The patent employs periodic action by alternating between different exposure duration cycles. The system periodically switches between long-exposure and short-exposure modes in a structured pattern that optimizes both brightness and sharpness capture within the overall acquisition timeframe
Data Source
AI summary
A method of combining image data from multiple frames to enhance one or more parameters of video image quality includes acquiring a first image at a first exposure duration, as well as acquiring a second image at a second exposure duration shorter than the first exposure duration and at a time just before, just after or overlapping in time with acquiring the first image, such that the first and second images include approximately a same first scene. In this way, the second image is relatively sharp and under-exposed, while the first image is relatively well-exposed and less sharp than the second image. Brightness and/or color information are extracted from the first image and applied to the second image to generate an enhanced version of the second image.